Technical Field

The present invention relates to a method and apparatus for deposition of material on a substrate.

Background

Deposition is a process by which material is provided on a substrate. An example of deposition is thin film deposition in which a thin layer (typically from around a nanometre or even a fraction of a nanometre up to several micrometres or even tens of micrometres) is deposited on a substrate, such as a silicon wafer or web. In some cases, it is desirable to provide a pattern of deposited material on a surface of a substrate, rather than coating the entire surface. Furthermore, it is desirable to create the pattern of material on the surface of the substrate without the addition of further processing steps, to create the pattern of material in an efficient manner.

Summary

According to a first aspect of the present invention, there is provided a deposition system comprising a deposition source to provide material to deposit on a substrate within a deposition zone, a conveyor system arranged to move the substrate relative to the deposition zone, and a mask transport system arranged to move a mask between the deposition source and the substrate from a first side of the deposition zone to a second side of the deposition zone, different from the first side of the deposition zone. The deposition system is further configured so that the conveyor system is operable to move the substrate at a first speed and the mask transport system is operable to move the mask at a second speed, different from the first speed. Arranging a mask between the deposition source and the substrate provides the ability to efficiently deposit patterns of the material on the substrate, as the mask may block some or all of the material from the deposition source from being deposited on the substrate. By controlling the speed of the mask with respect to the speed of the substrate, the characteristics of the deposition patterns can be controlled in an efficient manner. Furthermore, the deposition patterns are created in an efficient manner, without the addition of further processing steps.

The conveyor system may be arranged to move the substrate in a first direction and the mask transport system may be arranged to move the mask in a second direction. In some examples, the first direction may be substantially parallel to the second direction e.g. the substrate and the mask may move in substantially the same direction. In other examples, the first direction may substantially perpendicular to the second direction e.g. the substrate and the mask may move at right angles to each other. By controlling the direction of movement of the mask with respect to the direction of movement of the substrate, deposition patterns of the material deposited on the substrate may be created in an efficient manner.

The conveyor system may be arranged to support the substrate, or the mask transport system may be arranged to support the mask such that there is a space between the mask and the substrate, when the deposition system is in use. Such an arrangement may allow the speed of the mask to be more easily controlled, relative to the speed of the substrate, without resistance resulting from the physical contact of the substrate and the mask.

During the deposition of the material on the substrate, the mask transport system may be arranged to move the mask between the deposition source and the substrate in order to create a layer of the material on the substrate which comprises a gap. Creating a gap in the layer of the material on the substrate provides the ability to create patterns of material as desired on the substrate. In examples in which the deposition system is used during manufacture of an energy storage device, creating a gap provides the ability to create cells with smaller surface areas as part of the deposition process. This may reduce the capacity of each cell and reduce the risk of a thermal run-away in the event of a short circuit. Creating a gap during the deposition process, without the addition of further processing steps, creates a gap in an efficient manner.

The first speed may be changeable relative to the second speed. Changing the relative speeds of the substrate (moving at a first speed) and the mask (moving at a second speed) provides the ability to change the size of the gap in the layers deposited on the substrate. As such, successive layers deposited on the substrate may have different sized gaps, therefore creating stepped layers e.g. successive layer has a larger gap than the previous layer. This means that, wherein the deposition system is used to manufacture an energy storage device comprising a first electrode layer, a second electrode layer and an electrolyte layer between the first and second electrode layer, there is less likelihood of the first electrode layer coming into physical contact with the second electrode layer, causing a short circuit.

The mask transport system may comprise a cleaning system to clean the mask. During the deposition process, the amount of material deposited on the mask increases. As a result, the edges of the gaps may become less distinct, e.g. less sharp and accurate. In such a scenario, this may cause an increase in the likelihood of short circuits or other defects between the layers on the substrate. Therefore, cleaning the mask regularly, to decrease or remove the collected material may help to reduce this effect.

The mask may comprise a wire. The wire may be used in order to create a narrow gap in the layer on the substrate. Different diameters, or thicknesses, of wire may be selected based on the required length of the gap.

The deposition source may comprise a vapour deposition source. The vapour deposition source may comprise a thermal deposition source. The vapour deposition source may comprise a sputter deposition source. The deposition source may be selected based on the material to deposit on the substrate. Selecting the deposition source based on the properties of the material to be deposited may provide a more efficient deposition process.

The conveyor system may be a roll-to-roll system. The mask transport system may be a roll-to-roll system. In such a way, gaps in the layers of material deposited on the substrate may be created in an efficient manner.

The mask transport system may be arranged to move the mask from the second side of the deposition zone back to the first side of the deposition zone by moving the mask beneath the deposition source. The mask transport system may be a continual loop system whereby moving the mask around the continual loop system brings the mask back to where it started, to create an efficient way of transporting the mask.

The mask transport system may be arranged to move a plurality of masks. In such cases, the movement of the substrate and the movement of the masks may be synchronised so that the gaps of successive layer of material deposited on the substrate occur in substantially the same place, therefore creating stepped layers. There may be a plurality of masks of different sizes that are used to create gaps in the layers, where each layer has a different sized gap corresponding to the size of the mask used.

The deposition system may be arranged for use in manufacture of an energy storage device. It may be desirable to create a cell of an energy storage device with a smaller surface area to reduce the capacity of each cell and reduce the risk of a thermal run-away in the event of a short circuit. This may improve the safety of the manufacturing of the cells. It may also desirable to create smaller surface areas without performing an additional step in the manufacturing process, in order to avoid increasing the production time for the energy storage device.

In accordance with a second aspect of the present invention, there is provided a method comprising moving a substrate relative to a deposition zone, wherein the deposition zone comprises a material to be deposited on the substrate. The method further comprises, during moving the substrate, moving a mask between the substrate and a deposition source for providing the material, and from a first side of the deposition zone to a second side of the deposition zone, different from the first side of the deposition zone, wherein the substrate is moved at a first speed and the mask is moved at a second speed different from the first speed. Arranging a mask between the deposition source and the substrate provides the ability to efficiently deposit patterns of the material on the substrate, as the mask may block some or all of the material from the deposition source from being deposited on the substrate. By controlling the speed of the mask with respect to the speed of the substrate, the characteristics of the deposition patterns can be controlled in an efficient manner. Furthermore, the deposition patterns are created in an efficient manner, without the addition of further processing steps.

Moving the mask between the deposition source and the substrate, during deposition of the material on the substrate, may create a layer of the material on the substrate which comprises a gap. Creating a gap in the layer of the material on the substrate provides the ability to create patterns of material as desired on the substrate. In examples in which the deposition system is used during manufacture of an energy storage device, creating a gap provides the ability to create cells with smaller surface areas as part of the deposition process. This may reduce the capacity of each cell and reduce the risk of a thermal run-away in the event of a short circuit. Creating a gap during the deposition process, without the addition of further processing steps, creates a gap in an efficient manner.

When the layer of the material is a first layer of a first material and the gap is a first gap, the deposition source may be further arranged for providing a second material. The method may further comprise moving the mask or a further mask between the deposition source and the substrate, during deposition of the second material on the substrate, to create a second layer of the second material on the substrate which comprises a second gap. As such, successive layers may be deposited on the substrate.

The first material may be provided for deposition on the substrate during a first time period in which the first speed is substantially equal to the second speed. The second material may be provided for deposition on the substrate during a second time period in which the first speed is different from the second speed. Therefore, successive layers may be deposited on the substrate which have different sized gaps. This may create stepped layers e.g. each successive layer has a larger gap than the previous layer. This means that there, for example, is less likelihood of one layer coming into physical contact with another layer, e.g. causing a short circuit.

The second material may be provided for deposition on the substrate while the first speed is slower than the first speed in order to create the second gap in the second layer, wherein the second gap is larger than the first gap.

The first material may comprise material for an electrode layer of an energy storage device and the second material may comprise material for an electrolyte layer of the energy storage device.

In accordance with a third aspect of the present invention, there is provided an energy storage device manufactured in accordance with the method in accordance with the second aspect of the present invention.

In accordance with a fourth aspect of the present invention, there is provided a deposition system comprising a deposition source to provide material to deposit on a substrate within a deposition zone, a conveyor system arranged to move the substrate relative to the deposition zone, and a mask transport system arranged to move a mask between the deposition source and the substrate from a first side of the deposition zone to a second side of the deposition zone, different from the first side of the deposition zone. The deposition system is further configured so that the conveyor system is operable to move the substrate at a first speed and the mask transport system is operable to move the mask at a second speed, substantially equal to the first speed. Arranging a mask between the deposition source and the substrate provides the ability to efficiently deposit patterns of the material on the substrate, as the mask may block some or all of the material from the deposition source from being deposited on the substrate. Furthermore, the deposition patterns are created in an efficient manner, without the addition of further processing steps.

The mask transport system may be arranged to move the mask between the deposition source and the substrate, during deposition of the material on the substrate, in order to create a layer of the material on the substrate which comprises a gap. Creating a gap in the layer of the material on the substrate provides the ability to create patterns of material as desired on the substrate. In examples in which the deposition system is used during manufacture of an energy storage device, creating a gap provides the ability to create cells with smaller surface areas as part of the deposition process. This may reduce the capacity of each cell and reduce the risk of a thermal run-away in the event of a short circuit. Creating a gap during the deposition process, without the addition of further processing steps, creates a gap in an efficient manner.

The mask transport system may be arranged to move at least a first mask and a second mask, wherein the second mask is larger than the first mask. Using the first mask when a first material is deposited on the substrate and using the second mask is deposited on the substrate may create successive layers on the substrate with different sized gaps e.g. each successive layer may have a larger gap than the previous layer. This means that, wherein the deposition system is used to manufacture an energy storage device comprising a first electrode layer, a second electrode layer and an electrolyte layer between the first and second electrode layer, there is less likelihood of the first electrode layer coming into physical contact with the second electrode layer, causing a short circuit.

The conveyor system may be arranged to support the substrate, or the mask transport system may be arranged to support the mask such that there is a space between the mask and the substrate, when the deposition system is in use. Such an arrangement may allow the speed of the mask to be more easily controlled, relative to the speed of the substrate, without resistance resulting from the physical contact of the substrate and the mask.

The deposition system may be arranged for use in manufacture of an energy storage device. It may be desirable to create a cell of an energy storage device with a smaller surface area to reduce the capacity of each cell and reduce the risk of a thermal run-away in the event of a short circuit. This may improve the safety of the manufacturing of the cells. It may also desirable to create smaller surface areas without performing an additional step in the manufacturing process, in order to avoid increasing the production time for the energy storage device.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.

Brief Description of the Drawings

Figure la is a schematic diagram of layers on a substrate according to examples;

Figure lb is a schematic diagram of non-continuous layers on a substrate according to examples;

Figures 2a to 2c are schematic diagrams illustrating a method of creating a layer on a substrate according to examples;

Figures 3a to 3c are schematic diagrams illustrating a method of depositing a plurality of layers on a substrate according to examples;

Figure 4 is a schematic diagram of a deposition system according to examples;

Figure 5 is a schematic diagram of a deposition system according to further examples;

Figures 6a to 6d are schematic diagrams illustrating masks and resulting deposition patterns according to examples;

Figure 7 is a schematic diagram of a deposition system according to further examples;

Figure 8 is a flow diagram illustrating a method of creating a layer on a substrate according to examples. Detailed Description

Details of methods and systems according to examples will become apparent from the following description, with reference to the Figures. In this description, for the purpose of explanation, numerous specific details of certain examples are set forth. Reference in the specification to "an example" or similar language means that a particular feature, structure, or characteristic described in connection with the example is included in at least that one example, but not necessarily in other examples. It should further be noted that certain examples are described schematically with certain features omitted and/or necessarily simplified for ease of explanation and understanding of the concepts underlying the examples.

As explained above, deposition is a process by which material is provided on a substrate. Deposition techniques can be used to provide a series of layers on a substrate, sometimes referred to as a stack of layers. Deposition techniques may be used in a wide number of industrial applications, such as those which have utility for the deposition of thin films, such as in the production of optical coatings, magnetic recording media, electronic semiconductor devices, LEDs, energy generation devices such as thin-film solar cells, and energy storage devices such as thin-film batteries.

In order put the systems and methods described herein into context, Figure la is provided, which shows an example of an energy storage device that may be manufactured using the systems and methods described. However, it should be noted that the systems and methods described herein may be used to manufacture other structures and Figure la is merely an example.

Figure la shows a stack 100 of layers for an energy storage device. The stack 100 of Figure la may be used, for example, as part of a thin-film energy storage device having a solid electrolyte.

The stack 100 is on a substrate 102 in Figure la. The substrate 102 is for example glass or polymer and may be rigid or flexible. The substrate 102 is typically planar. Although the stack 100 is shown as directly contacting the substrate 102 in Figure la, there may be one or more further layers between the stack 100 and the substrate 102 in other examples. Hence, unless otherwise indicated, reference herein to an element being “on” another element is to be understood as including direct or indirect contact. In other words, an element on another element may be either touching the other element, or not in contact the other element but, instead, generally supported by an intervening element (or elements) but nevertheless located above, or overlapping, the other element.

The stack 100 of Figure la includes a first electrode layer 104, an electrolyte layer 106 and a second electrode layer 108. In the example of Figure la, the second electrode layer 108 is further from the substrate 102 than the first electrode layer 104, and the electrolyte layer 106 is between the first electrode layer 104 and the second electrode layer 108.

The first electrode layer 104 may act as a positive current collector layer. In such examples, the first electrode layer 104 may form a positive electrode layer (which may correspond with a cathode during discharge of a cell of the energy storage device including the stack 100). The first electrode layer 104 may include a material which is suitable for storing lithium ions by virtue of stable chemical reactions, such as lithium cobalt oxide, lithium iron phosphate or alkali metal polysulphide salts.

In alternative examples, there may be a separate positive current collector layer, which may be located between the first electrode layer 104 and the substrate 102. In these examples, the separate positive current collector layer may include nickel foil, but it is to be appreciated that any suitable metal could be used, such as aluminium, copper or steel, or a metalised material including metalised plastics such as aluminium on polyethylene terephthalate (PET).

The second electrode layer 108 may act as a negative current collector layer. The second electrode layer 108 in such cases may form a negative electrode layer (which may correspond with an anode during discharge of a cell of an energy storage device including the stack 100). The second electrode layer 108 may include a lithium metal, graphite, silicon or indium tin oxide (ITO). As for the first electrode layer 104, in other examples, the stack 100 may include a separate negative current collector layer, which may be on the second electrode layer 108, with the second electrode layer 108 between the negative current collector layer and the substrate 102. In examples in which the negative current collector layer is a separate layer, the negative current collector layer may include nickel foil. It is to be appreciated, though, that any suitable metal could be used for the negative current collector layer, such as aluminium, copper or steel, or a metalised material including metalised plastics such as aluminium on polyethylene terephthalate (PET).

The first and second electrode layers 104, 108 are typically electrically conductive. Electrical current may therefore flow through the first and second electrode layers 104, 108 due to the flow of ions or electrons through the first and second electrode layers 104, 108.

The electrolyte layer 106 may include any suitable material which is ionically conductive, but which is also an electrical insulator, such as lithium phosphorous oxynitride (LiPON). As explained above, the electrolyte layer 106 is for example a solid layer, and may be referred to as a fast ion conductor. A solid electrolyte layer may have structure which is intermediate between that of a liquid electrolyte, which for example lacks a regular structure and includes ions which may move freely, and that of a crystalline solid. A crystalline material for example has a regular structure, with an ordered arrangement of atoms, which may be arranged as a two dimensional or three dimensional lattice. Ions of a crystalline material are typically immobile and may therefore be unable to move freely throughout the material.

The stack 100 may for example be manufactured by depositing the first electrode layer 104 on the substrate 102. The electrolyte layer 106 is subsequently deposited on the first electrode layer 104, and the second electrode layer 108 is then deposited on the electrolyte layer 106. Each layer of the stack 100 may be deposited by for example physical vapour deposition or thermal deposition, although other deposition methods are possible.

The stack 100 and the substrate 102 together form an intermediate structure 110 for the manufacture of an energy storage device. The intermediate structure 110 may be flexible, allowing it to be wound around a roller as part of a roll-to-roll manufacturing process (sometimes referred to as a reel-to-reel manufacturing process). Continuous deposition of the layers of the stack 100 onto the substrate 102 may create a continuous roll of intermediate structure 110 around the roller. The intermediate structure 110 may therefore be a continuous cell with a large surface area.

The intermediate structure 110 may be gradually unwound from the roller and subjected to further processing. For example, the intermediate structure 110 may be cut into separate sections to form individual solid-state cells. Upon deposition of the last layer (the second electrode layer 108) and before being cut into individual solid-state cells, the intermediate structure 110 may have a large surface area. In general, the more electrode material contained within a cell, the greater the capacity of the cell i.e. the amount of electric charge that can be delivered at a given voltage. As a result, an intermediate structure 110 with a large surface area may have a large capacity.

Any defects in the deposition of layers may create a short circuit between the layers. For example, a defect in the deposition of the electrolyte layer 106 may create a short circuit between the first electrode layer 104 and the second electrode layer 108. For cells with a large surface area, such as intermediate structure 110, the capacity of the cell is large. A short circuit may therefore cause a thermal mn-away event, which may cause the material to spontaneously ignite.

It is therefore desirable to create cells with smaller surface areas as part of the deposition process, to reduce the capacity of each cell and reduce the risk of a thermal run-away in the event of a short circuit. Creating non-continuous cell areas during the deposition process may improve the safety of the manufacturing of the cells. Non- continuous cell areas are for example cell areas which are disconnected from or otherwise not in electrical contact with each other. An example of creating non- continuous cell areas from the stack 100 of Figure la is shown schematically in Figure lb. It is also desirable to create smaller surface areas without performing an additional step in the manufacturing process, in order to avoid increasing the production time.

Figure lb shows non-continuous cell areas 100a, 100b on a substrate 102, which may be referred to as first and second finite stacks 100a, 100b respectively. In Figure lb, the continuous area of stack 100 of Figure la has been modified to create a non- continuous stack including the first finite stack 100a and the second finite stack 100b. The first finite stack 100a comprises a first portion 104a of a first electrode layer 104’, a first portion 106a of an electrolyte layer 106’ and a first portion 108a of a second electrode layer 108’. The second finite stack 100b comprises a second portion 104b of a first electrode layer 104’, a second portion 106b of an electrolyte layer 106’ and a second portion 108b of a second electrode layer 108’ to create a second finite stack 100b. The first finite stack 100a is separated from the second finite stack 100b by gaps 104c, 104c, 106c within the layers of the stack 100. For example, the first electrode layer 104 of Figure 1 is split into two by the gap 104c to create the non-continuous first electrode layer 104’ of Figure lb, which includes first and second portions 104a, 104b which form part of the first and second finite stacks 100a, 100b respectively. Similarly, the electrolyte layer 106 of Figure la is split into two by the gap 106c to create the non- continuous electrolyte layer 106’ of Figure lb, which includes first and second portions 106a, 106b which form part of the first and second finite stacks 100a, 100b respectively. Finally, the second electrode layer 108 of Figure la is split into two by the gap 108c to create the non-continuous second electrode layer 108’ of Figure lb, which includes first and second portions 108a, 108b which form part of the first and second finite stacks 100a, 100b respectively.

The first and second finite stacks 100a, 100b of Figure lb have a smaller surface area than the stack 100 of Figure la. The size of the surface area of the first and second finite stacks 100a, 100b may be chosen such that in the event of a short circuit, the capacity stored in the first and second finite stacks 100a, 100b reduces the risk of, or is insufficient to cause, a thermal-runaway event. For example, in the event of a short circuit in the first finite stack 100a, only the thermal capacity stored in the first finite stack 100a will contribute to the thermal run-away event. Due to the gaps 104c, 106c, 108c between the first finite stack 100a and the second finite stack 100b, the thermal capacity stored in second finite stack 100b will not contribute to the event, and thermal run-away will be contained. As such, the likelihood of the material spontaneously igniting is reduced.

In order to further decrease the likelihood of shorts between layers, e.g. between the first portion 104a and the second portion 108a of the first finite stack 100a, the layers may be manufactured with ‘stepped’ edges. Continuing the example of the first finite stack 100a, the edges of each successive portion 104a, 106a, 108a are stepped, e.g. such that each successive layer is shorter in length than the previous layer. This means that there is less likelihood of for example the first portion 108a of the non- continuous second electrode layer 108’ coming into physical contact with the first portion 104a of the non-continuous first electrode layer 104’, causing a short circuit.

Figures 2a to 2c show a method of creating a layer 204’ on a substrate 202 during a deposition process. The layer 204’ is for example a non-continuous layer, such as the non-continuous first electrode layer 104’ of Figure lb, although this is merely an example. For example, the layer 204’ may comprise different materials than those of the non-continuous first electrode layer 104’ and/or may be used for a different purpose than the non-continuous first electrode layer 104’. Features of Figures 2a to 2c which are similar to corresponding features of Figures la and lb are labelled with the same reference numeral but incremented by 100. Corresponding descriptions are to be taken to apply, unless otherwise stated.

Figures 2a to 2c show three stages of a method of creating the layer 204’ on a substrate 202 during a deposition process. The Figures 2a to 2c can be thought of as three snapshots of a process. During the process, a deposition source 120 may be continually providing material 204d to be deposited on the substrate 202.

Figures 2a to 2c show a deposition source 120 to provide material 204d to deposit on a substrate 202. The deposition source may be a vapour deposition source such that the material in the vapour deposition source is vaporised and then condensed onto the substrate to create a layer on the substrate.

The vapour deposition source may be a thermal deposition source e.g. an evaporation deposition source. With a thermal deposition source, the material in the source is thermally heated in a vacuum to evaporate the material into a vapour. The vapour material then condenses back to a solid state onto the substrate, to create a layer or film on the substrate. In some examples, the material in the source is thermally heated by use of an electron beam incident on the material in the source. In other examples, the material in the source is thermally heated by resistive heating or radiative heating.

The vapour deposition source may be a sputter deposition source. With a sputter deposition source, a target is bombarded with energetic particles. The energetic particles may collide with the atoms on the surface of the target, ejecting the atoms from the surface of the target. These atoms may then be deposited onto a substrate to form a layer or film on the substrate. The source of the energetic particles may be a plasma, situated above the target. By applying a negative voltage to the target surface, the positive ions from the plasma are accelerated into the surface of the target. The release of secondary electrons from the surface of the target may help sustain the plasma.

The material 204d may, for example, be material suitable for use as a first electrode layer, such as lithium cobalt oxide, lithium iron phosphate or alkali metal polysulphide salts, although other materials are possible in other examples. The material 204d may be deposited on the substrate 202 within a deposition zone 140. The location of the deposition zone 140, in relation to the deposition source 120 and the substrate 202, is illustrated by the dashed lines of Figures 2a to 2c. The deposition zone 140 is characterised as the area above the deposition source 120 in which material 204d from the deposition source 120 may be deposited on the substrate 202. The movement of the material 204d in the deposition zone 140, from the deposition source 120 to the substrate 202, is indicated by the hatched arrows of Figures 2a to 2c. The hatching pattern of the arrow matches the hatching pattern of the material 204d (from the deposition source 120) and matches the hatching pattern of the layer 204’ to indicate that each element in the Figure comprises the same material.

During the process, the substrate 202 may be conveyed across the deposition zone 140 by a conveyor system, which is not shown in Figures 2a to 2c. A conveyance direction in which the substrate 202 is conveyed is indicated by the arrow 122, and in this case is to the right of Figures 2a to 2c. Similarly, the mask may be moved across the deposition zone 140 by a mask transport system, which is also not shown in Figures 2a to 2c. The three snapshots of the process, Figures 2a to 2c, show three different positions of the mask 130, as the mask 130 is moving from a first side of the deposition zone 140 in Figure 2a (on the left of the deposition zone 140 in this example), to above the deposition source in the deposition zone 140 in Figure 2b, to a second side of the deposition zone 140 in Figure 2c (on the right of the deposition zone 140 in this example). The transport direction of the mask is from the left to the right in this example.

The mask 130, which may be referred to as a shutter or shadow mask, is configured such that when the mask 130 is located between a deposition source 120 and a substrate 202, the mask 130 may block some or all of the material 204d from the deposition source 120 from being deposited on the substrate 202 i.e. the mask creates a shadow on the substrate.

The mask 130 may be manufactured from a material with a high-temperature strength, in order to avoid the mask disfiguring when in the vicinity of the high temperature of the deposition zone 140. The mask 130 may be manufactured from, although not limited to, materials such as metal, metal alloys, silicon, ceramics or heat- resistant polymers. The mask 130 may be rigid or flexible. For example, the mask may be manufactured from a metal such as nickel, although many other options are possible. Materials with a high-temperature strength and a high-temperature oxidation resistance are especially beneficial, due to the high temperature that may be encountered over the deposition source in the deposition zone 140. For example, the mask may be manufactured from metal alloy such as stainless steel, which provides good strength and good resistance to corrosion and oxidation at high temperatures, which may increase the lifetime of the mask.

In other examples, the temperature of the deposition zone 140 may be such that manufacturing the mask 130 from a material with a high-temperature strength is not necessary. For example, the temperature in the vicinity of the deposition zone 140 may be such that a mask 130 with a lower temperature strength may be utilised e.g. for deposition of material 204d such as lithium on the substrate 202. The mask 130 in such cases may be manufactured from, although not limited to, materials such as plastics or polymers. The mask 130 may be rigid or flexible.

In Figure 2a, a mask 130 is shown at a first side of the deposition zone 140, which in this example is on the left of the deposition zone 140. As the mask 130 is to one side of the deposition zone 140, the mask 130 does not affect the deposition of the material 204d on the substrate 202. As such, a layer of material 204d is deposited on the substrate 202 to form a first portion 204a of a layer 204’. Movement of the substrate 202 is indicated by the arrow 122. The substrate may be moved by a conveyor system (not shown). As the substrate moves to the right relative to the deposition zone 140, material 204d can be deposited on the substrate 202 in the deposition zone 140, and then moved away from the deposition zone 140. This forms a first portion 204a of a layer 204’ of material 204d e.g. forming a first portion of a first electrode layer, such as the non-continuous first electrode layer 104’ of Figure lb.

In Figure 2b, the mask is shown in the deposition zone 140 i.e. above the deposition source 120. The mask may be moved from the first side of the deposition zone 140 to the deposition zone 140 by a mask transport system (not shown). As the mask 130 is above the deposition source 120, the mask 130 may block some or all of the material 204d from the deposition source 120 from being deposited on the substrate 202. In other words, a shadow of the mask 130 is created on the substrate 102 by the presence of the mask 130 between the deposition source 120 and the substrate 102. The blocking of the material 204d from the deposition source 120 may cause an area 204c, e.g. a gap 204c, on the substrate that does not contain any deposited material 204d.

In Figure 2c, the mask is shown at a second side of the deposition zone 140, which is on the right of the deposition zone 140 in Figure 2c. The mask may be moved from the deposition zone 140 to the second side of the deposition zone 140 by the mask transport system (not shown). As the mask 130 is to one side of the deposition zone 140, the mask 130 does not affect the deposition of the material 204d on the substrate 202. As such a layer of material 204d is deposited on the substrate to form a second portion 204b of a layer 204’. As the substrate continues to move to the right relative to the deposition zone 140, material 204d can be deposited on the substrate 202 in the deposition zone 140, and then moved away from the deposition zone 140. This forms a second portion 204b of a layer 204’ of material 204d e.g. forming a second portion of a first electrode layer such as the second portion 104b of the non-continuous first electrode layer 104’ of Figure lb. The first portion 204a of the layer 204’ is separated from the second portion 204b of the layer 204’ by the presence of the gap 204c, thus creating a layer 204’ which may be referred to as a non-continuous layer.

In the above example, the movement of the substrate, as conveyed by the conveyor system, is equal to the movement of the mask, as transported by the mask transport system. This creates a gap 204c within the layer 204’that has the same dimensions as that of the mask 130. In other words, the distance of separation between the first portion 204a and the second portion 104b of the layer 104’ i.e. the length of the gap 204c, equals the length of the mask 130. As will be explained in the following examples, the length of the gap within the layers may be controlled by the movement of the substrate and the movement of the mask, relative to each other. In this way, a pattern of material on a substrate may be created in an efficient manner. For example, a method such as that of Figures 2a to 2c allows a layer of material including a gap between respective portions of the material to be provided on a substrate without the addition of further processing steps. This may therefore allow the material to be provided more efficiently than otherwise. In this case, the material is deposited with the desired pattern (which in this example includes the gap 204c) without material subsequently being removed from the substrate 202. This may further reduce wastage of the material. Figures 3a to 3c show a method of depositing a plurality of layers on a substrate 302 during a deposition process. The method of Figures 3a to 3c may be used to create a finite stack, such as the finite stacks 100a, 100b of Figure lb, although this is not intended to be limiting.

The Figures 3a to 3c can be thought of as three snapshots of a process. During the process, a deposition source 120 may provide different materials 304d, 306d, 308d to be deposited on the substrate 302. For example, a first material 304d may be deposited on a substrate 302 in Figure 3a to create a first layer 304’; a second material 306d may be deposited on the first layer 304’ in Figure 3b to create a second layer 306’; and a third material 308d may be deposited on the second layer 306’ in Figure 3c to create a third layer 308’ . In order to simplify the explanation and aid understanding, the substrate 302 is in the same position, relative to the deposition source 120 and the mask 130, in each snapshot of the process.

The layers 304’, 306’, 308’ are for example non-continuous layers, such as the non-continuous first electrode layer 104’, the non-continuous electrolyte layer 106’ and the non-continuous second electrode layer 108’ of Figure la, although this is merely an example. Features of Figures 3a to 3c which are similar to corresponding features of Figures la and lb are labelled with the same reference numeral but incremented by 200. Corresponding descriptions are to be taken to apply, unless otherwise stated.

In some examples, the deposition source 120 may be the same deposition source which successively provides different materials 304d, 306d, 308d for the deposition process. In Figure 3a, the deposition source 120 may be first configured to provide the first material 304d for deposition on the substrate 302. In Figure 3b, the deposition source 120 may then be reconfigured to provide a different material (the second material 306d) for deposition on the first layer 304’. Reconfiguring may comprise replacing the first material 304d with the second material 306d. In Figure 3c, the deposition source 120 may then be further reconfigured to provide another material (the third material 308d) for deposition on the second layer 306’ . Further reconfiguring may comprise replacing the second material 306d with the third material 308d.

In other examples, the deposition source 120 may be a different deposition source that provides each different material 304d, 306d, 308d. A deposition source may be selected based on the ability of the deposition source to provide a particular material for deposition on the substrate. Different materials have different chemical and physical properties, so selection of a suitable deposition source may provide the ability to deposit the material in an efficient manner. For example, in Figure 3 a, a first deposition source may provide the first material 304d for deposition. For example, the first deposition source may be configured to deposit the first material 304d to create a first electrode layer. In an example, lithium cobalt oxide may be selected as the first material 304d to deposit to create the first electrode layer. The first deposition source may therefore be a thermal deposition source. In Figure 3d, a second deposition source may provide a second material for deposition. The second deposition source may be configured to deposit the second material 306d to create an electrolyte layer, for example. In an example, lithium phosphorous oxynitride (LiPON) may be selected as the second material 306d to deposit to create an electrolyte layer. The second deposition source may therefore be a sputter deposition source or an evaporative deposition source e.g. evaporating the material with use of an electron beam. In Figure 3c, a third deposition source may provide a third material 308d for deposition. The third deposition source may be configured to deposit the third material 308d to create a second electrode layer, for example. In an example, lithium may be selected as the third material 308d to deposit to create a second electrode layer. The third deposition source may therefore be a thermal deposition source e.g. using thermal evaporation technique to evaporate the lithium. In another example, a heavier metal (e.g. heavier than lithium) may be selected as the third material 308d to deposit to create the second electrode layer. In such cases, the heavier metal may require a higher temperature to evaporate the material into a vapour. As such, the third deposition source may therefore use an electron beam or induction heating to evaporate the heavier metal. Given the different properties that the materials 304d, 306d and 3068d may have, the configuration of the first, second and third deposition sources may be quite different from each other. For example, the first and third deposition sources may be thermal deposition sources or evaporation deposition sources and the second deposition source may be a sputter deposition source, in order to optimise the rates of deposition for each material.

In Figure 3a, a deposition source 120 provides the first material 304d to be deposited on a substrate 302 to form a first layer 304’ . In some examples, the first layer 304’ may comprise a first electrode layer, which is for example a non-continuous layer. The first electrode layer may form a positive electrode layer to act as a positive current collector layer. The first material 304d deposited on the substrate 302 may be a material which is suitable for storing lithium ions by virtue of stable chemical reactions, such as lithium cobalt oxide, lithium iron phosphate or alkali metal poly sulphide salts.

As described in relation to Figures 2a to 2c, when a mask 130 is present in a deposition zone 140 between the deposition source 120 and the substrate 302, the mask 130 may block some or all of the first material 304d from being deposited on the substrate 302. Blocking the first material 304d from being deposited on the substrate 302 causes a gap 304c in the first material 304d deposited on the substrate 302, which creates a first layer 304’ which is for example a non-continuous layer.

The substrate 302 may be moved by a conveyor system (not shown) as indicated by the arrow 122. The double-head of the arrow 122 indicates that the movement of the substrate 302 occurs at a first speed. The mask 130 may be moved by a mask transport system (not shown) in a direction 132 at a second speed as indicated by the arrow 134a. The speed of the mask 130 may be faster than the speed of the substrate 302, as shown in Figure 3a. The triple-head of the arrow 134a indicates that the movement of the mask 130 occurs at a speed faster than the speed of the substrate (as indicated by arrow 122).

In the scenario where the speed of the mask 130 is faster than the speed of the substrate 302, the gap 304c created by the movement of the mask 130 between the deposition zone 140 and the substrate 302 is shorter in length than the length of the mask 130. In other words, the distance of separation between the first portion 304a and the second portion 304b of the first layer 304’ i.e. the length of the gap 304c, is shorter than the length of the mask 130. Therefore, by moving the mask 130 at a speed 134a faster than the speed 122 of the substrate 302, a gap 304c can be created that is smaller than the size of the mask 130.

In Figure 3b, a deposition source 120 provides a second material 306d to be deposited on the first layer 304’ to form a second layer 306’. In some examples, the second layer 306’ may comprise an electrolyte layer. The second material 306d deposited on the first layer 304’ in such cases may be any suitable material which is ionically conductive, but which is also an electrical insulator, such as lithium phosphorous oxynitride (LiPON). Such an electrolyte layer may be a solid layer with a structure which is intermediate between that of a liquid electrolyte and that of a crystalline solid.

When the mask 130 is present in the deposition zone 140 between the deposition source 120 and the substrate 302, the mask 130 may block some or all of the second material 306d from being deposited on the first layer 304’ . Blocking the second material 306d from being deposited on the first layer 304’ causes a gap 306c in the second material 306d deposited on the substrate 302, which creates a second layer 306’, which is for example a non-continuous layer.

The substrate 302 may be moved by a conveyor system (not shown) as indicated by the arrow 122, as described in relation to Figure 3 a. The double-head of the arrow 122 indicates that the movement of the substrate 302 occurs at a first speed i.e. the same speed as indicated in Figure 3a. The mask 130 may be moved by a mask transport system (not shown) in a direction 132 at a speed as indicated by the arrow 134b. The speed of the mask 130 may be the same or substantially equal to the speed of the substrate 302. The double-head of the arrow 134d indicates that the movement of the mask 130 occurs at a speed substantially equal to the speed of the substrate (as indicated by arrow 122). The speed of the mask may be considered to be substantially equal to the speed of the substrate when the speed of the mask is approximately equal to the speed of the substrate, such as within measurement tolerances or with a velocity deviation of within plus or minus 1, 5 or 10 percent of the speed of the substrate.

In the scenario where the speed of the mask 130 is substantially equal to the speed of the substrate 302, the gap 306c created by the movement of the mask 102 between the deposition zone 140 and the substrate 302 is substantially equal in length to the length of the mask 130. In other words, the distance of separation between the first portion 306a and the second portion 306b of the second layer 306’ i.e. the length of the gap 306c, is substantially equal to the length of the mask 130. Deposition of a second layer 306’ with a gap 306c larger than the gap 304c associated with the first layer 304’ creates a stepped-edge layer. The length of the gap may be considered to be substantially equal to the length of the mask when the length of the gap is approximately equal to the length of the mask, such as within measurement tolerances or with a length deviation of within plus or minus 1, 5 or 10 percent of the length of the mask. In Figure 3c, a deposition source 120 provides a third material 308d to be deposited on the second layer 306’ to form a third layer 308’. In some examples, the third layer may comprise a second electrode layer. A second electrode layer may form a negative electrode layer to act as a negative current collector layer. The third material 308d deposited on the second layer 306’ may be a lithium metal, graphite, silicon or indium tin oxide (ITO).

When the mask 130 is present in a deposition zone 140 between the deposition source 120 and the substrate 302, the mask 130 may block some or all of the third material 308d from being deposited on the second layer 306’. Blocking the third material 308d from being deposited on the second layer 306’ causes a gap 308c in the third material 308d deposited on the substrate 302, which creates a third layer 308’, which is for example a non-continuous layer.

The substrate 302 may be moved by a conveyor system (not shown) as indicated by the arrow 122. The double-head of the arrow 122 indicates that the movement of the substrate 302 occurs at a first speed. The mask 130 may be moved by a mask transport system (not shown) in a direction 132 at a speed as indicated by the arrow 134c. The speed of the mask 130 may be slower than the speed of the substrate 302. The single head of the arrow 134c indicates that the movement of the mask 130 occurs at a speed slower than the speed of the substrate (as indicated by arrow 122).

In the scenario where the speed of the mask 130 is slower than the speed of the substrate 302, the gap 308c created by the movement of the mask 130 between the deposition zone 140 and the substrate 302 is longer in length than the length of the mask 130. In other words, the distance of separation between the first portion 308a and the second portion 308b of the third layer 308’ i.e. the length of the gap 308c, is longer than the length of the mask 130. Therefore, by moving the mask 130 at a speed 134a slower than the speed 122 of the substrate 302, a gap 308c can be created that is larger than the size of the mask 130. Deposition of a third layer 308’ with a gap 308c larger than the gap 306c associated with the second layer 306’ and the gap 304c associated with the first layer 304’ creates another stepped-edge layer. Deposition of the third layer 308’ for example creates a stack of layers. The stack and the substrate may together form an intermediate structure for the manufacture of an energy storage device, such as the intermediate structure 110 described with reference to Figure la. Stepped-edge layers results when each successive layer (e.g. 308’) that is deposited on to the substrate 302 and previously deposited layers (e.g. 306’, 304’) includes a larger gap than the layer (e.g. 306’) deposited immediately preceding the deposited layer (e.g. 308’). As such, the edges of a given layer, either side of the gap, are farther away from each other than the edges of preceding layers. Minimizing the overlap of the edges of the layers may help to minimize the possibility of the edges of one layer (e.g. 304’) coming into physical contact with the edges of another layer (e.g. 308’), which can reduce the likelihood of defects or other undesirable effects occurring.

For example, where the first layer 304’ is a non-continuous first electrode layer and the third layer 308’ is a non-continuous second electrode layer, physical contact between the first layer 304’ and the second layer 308’ may create a short circuit between the two layers 304’, 308’. Creating stepped edges for the layers may reduce the likelihood of a short circuit between the layers. Furthermore, as explained above, creating gaps between the layers creates smaller layers so that the capacity of the smaller stack may not cause a thermal run-away in the event of a short circuit.

Figure 4 is a schematic diagram of a deposition system 400 according to an example. The deposition system 400 comprises a deposition source 120 to provide a third material 408d on a substrate 402 within a deposition zone 140. The deposition system 400 further comprises a conveyor system 150a, 150b to move the substrate 402 relative to the deposition zone 140. The deposition system 400 further comprises a mask transport system 152a-152d (collectively referred to with the reference numeral 152) arranged to move a mask 130 between the deposition source 120 and the substrate 402. The mask transport system 152 is arranged to move the mask 130 from a first side of the deposition zone 140 to a second side of the deposition zone 140. In Figure 4, first and second layers, 404’ and 406’, have already been deposited and the deposition system is in the process of depositing a third layer 408’.

The layers 404’, 406’, 408’ are for example non-continuous layers, such as the non-continuous first electrode layer 104’, the non-continuous electrolyte layer 106’ and the non-continuous second electrode layer 108’ of Figure lb, although this is merely an example. Features of Figure 4 which are similar to corresponding features of Figures la and lb are labelled with the same reference numeral but incremented by 300. As shown in Figure 4, the conveyor system 150a, 150b is arranged to move the substrate 402 across the deposition zone 140, from the left side to the right side of Figure 4. Similarly, the mask transport system 152a-152d is arranged to move the mask 130 across the deposition zone 140 and above the deposition source 120, towards the right side of Figure 4 in this example. In this example therefore, the first side of the deposition zone 140 is on the left of the deposition source 120 and the deposition zone 140, and the second side of the deposition zone 140 is on the right of the deposition source 120 and the deposition zone 140. The first side of the deposition zone 140 is the side from which the mask 130 approaches the deposition zone 140 e.g. the mask 130 moves towards the deposition zone 150 from the left side. Similarly, the second side of the deposition zone 140 is the side to which the mask moves away from the deposition zone 140 e.g. the mask 130 moves away from the deposition zone 140 to the right side.

The conveyor system 150a, 150b moves the substrate 402 relative to the deposition zone 140. The conveyor system 150a, 150b may be a roll-to-roll or reel-to- reel system, as shown in Figure 4. The conveyor system 150a, 150b may comprise one or more rollers that assist in moving the substrate relative to the deposition zone 140. The substrate 402 may be flexible, allowing it to be wound around a roller 150a, 150b. For example, the substrate 402 may be first wound around a first roller 150a, gradually unwound from the roller 150a in order for material 408d to be deposited on the substrate 402 in the deposition zone 140, and then the substrate 402 may be wound around a second roller 150b. This creates a continuous roll of substrate 402. In other examples, though, the substrate 402 may be relatively rigid or inflexible. In such cases, the substrate 402 may be moved relative to the deposition zone 140 by the conveyor system without bending the substrate or without bending the substrate a substantial amount.

The roll of substrate 402 may have none, one or more layers 404’, 406’ on the substrate 402 when it is wound around the roller 150a. In the example shown, there is a first layer 404’ and a second layer 406’ on the substrate 402 before a third layer 408’ is deposited in the deposition zone 140. As the roll of substrate 402 is gradually unwound from the roller 150a, the conveyor system 150a, 150b moves the substrate 402 from the first side of the deposition zone 140 to the second side of the deposition zone 140. The conveyor system may move the substrate 402 at a first speed, as indicated by arrow 122. The speed 122 of the substrate 402 may be controlled by the conveyor system 150a, 150b. The speed 122 may be controlled by a controller linked to the conveyor system. For example, the controller may be electronically linked to an electronic circuit which may control the speed of one or more electric motors. The electric motor may be coupled to one or more of the rollers 150a, 150b in order to wind and unwind the rollers 150a, 150b in synchronisation, thus moving the substrate at a first speed. Controlling the speed of the substrate may comprise controlling the voltage, current and or frequency applied to the electric motor.

In some examples, the conveyor system 150a, 150b may be a geared system comprising one or more gears to move the substrate 402 at a suitable speed 122. The speed 122 of the substrate 402 may be controlled by one or more electric motors that drive the geared system. Synchronisation of the speed 122 of the substrate 402 may be achieved by selecting a suitable gear ratio. For example, a first gear ratio may be selected to move the substrate 402 at a first speed and a second gear ratio may be selected to move the substrate 402 at a second speed.

As described above, the material 204d in the deposition source 120 is thermally heated in a vacuum to evaporate the material 204d into a vapour. In some examples, the conveyor system 150a, 150b may also be contained within the vacuum e.g. within a vacuum chamber.

The mask transport system 152a-152d moves the mask 130 relative to the deposition zone 140. The mask transport system 152a- 152d may be a roll-to-roll or reel- to-reel system, as shown in Figure 4. The mask transport system 152a-152d may comprise one or more rollers that assist in moving the mask 130 relative to the deposition zone 140. The mask may be flexible, allowing it to travel around one or more rollers 152a, 152b, 152c, 152d.

The mask transport system 152a-152d may move the mask 130 at a second speed, as indicated by arrow 134c. The speed 134c of the mask may be slower, substantially equal to or faster than the speed 122 of the substrate. The speed 134c of the mask 130 may be controlled by the mask transport system 152a- 152d. The speed 134c may be controlled by a controller linked to the mask transport system. For example, the controller may be electronically linked to an electronic circuit which may control the speed of one or more electric motors. The electric motor may be coupled to one or more of the rollers 152a, 152b, 152c, 152d in order to move the rollers 152a, 152b, 152c, 152d in synchronisation, thus moving the mask at the second speed. Controlling the speed of the substrate may comprise controlling the voltage, current and/or frequency applied to the electric motor. In some examples, the frequency and voltage applied to the electric motor may be controlled by a variable frequency drive system, which may be referred to as an inverter drive system.

In some examples, the speed of the substrate may be linked to the speed of the mask, for example so that the speed of the mask depends on or is otherwise related to the speed of the substrate. Linking the speed of the substrate with the speed of the mask may be performed in hardware, in software or in a mixture of both hardware and software. For example, the speeds may be linked in hardware by using the same electric motor to move the substrate and mask, the same electronic circuit to control the speed of one or more electric motors and/or a physical connection between the conveyor system and the mask transport system. Further examples may include controlling the voltage, current and/or frequency applied to one or more of the electric motors. In other examples, the speeds may be linked in software by configuring control software (of the controller) to control the speed of the substrate and the speed of the mask i.e. by controlling the voltage, current and/or frequency applied to one or more of the electric motors via the control software of the controller.

The speed of the mask may, for example, be linked to the speed of the substrate such that the speed of the mask may be configured to be a ratio or multiple of the speed of the substrate. Alternatively, the speed of the mask may, for example, be linked to the speed of the substrate such that the speed of the mask is a pre-determined speed (i.e. a pre-determined number of millimetres per second or centimetres per second) faster or slower than the speed of the substrate.

In some examples, the speed of the mask and/or the speed of the substrate may be changed relative to each other on the fly e.g. while the deposition process is in progress. This may be based on measurements of the material deposited on the substrate e.g. the width of a gap in a given layer of the stack, the thickness of the layer on the substrate, the degree of overlap between successive layers and/or gaps on the substrate etc. Continuous or intermittent measurements of the material deposited on the substrate may allow the speed of the mask and/or speed of the substrate to be optimised on the fly, in order to optimise the deposition of the layers on the substrate.

In Figure 4, as described in relation to Figure 3c, the speed 134c of the mask is slower than the speed 122 of the substrate. Hence the speed of the substrate 402 is shown with a double-headed arrow 122 in Figure 4 and the speed of the mask 130 is shown with a single-headed arrow 134c. In such a scenario, deposition of the third material 408d on the second layer 406’ creates a third layer 408’ on the substrate to create a stack of layers.

The mask transport system 152a-152d may move the mask 130 around the deposition source 120 in a continual loop. Using two or more rollers, for example the four rollers 152a, 152b, 152c, 152d shown in Figure 4, the mask transport system may move the mask 130 above the deposition source 120, between the deposition zone 140 and the substrate 402, travelling from left to right at a speed 134c. The mask transport system 152a-152d may then continue to move the mask around roller 152b and around roller 152c so that the mask 130 is below the deposition source. The mask transport system 152a-152d may then move the mask 120 below the deposition source 120, travelling from right to left at the speed 134c. Finally, the mask transport system 152a- 152d may then continue to move the mask around roller 152d and around roller 152a so that the mask 130 is once again above the deposition source 120, in the same place as it started. As such, the mask transport system 152a- 152d may move the mask 130 in a continual loop, re-using the same mask to create gaps in the layers of the material deposited on the substrate 402. This for example allows the layers to be deposited in a continuous manner, or with fewer breaks or pauses in deposition than otherwise. This can improve the efficiency of deposition of the layers.

Movement of the mask 130 may be synchronised with the movement of the substrate 402 in order to create synchronised gaps in the successive layers of the materials deposited on the substrate 402, so that the gaps 404c, 406c, 408c, in each layer 404’, 406’, 408’ occur in substantially similar regions on the substrate 402. In some examples, data relating to the position of the mask 130 in the mask transport system 152a-152d may be provided as feedback to the controller of the mask transport system 152a- 152d and/or the controller of the conveyor system 150a, 150b. In some examples, a single controller acts to control the mask transport system 152a-152d and the conveyor system 150a, 150b. From the position of the mask, one or more controllers may control the movement of the mask 130 relative to the movement of the substrate 402 when the mask 130 is in the region of the deposition zone 140 and/or elsewhere.

Regions may be considered substantially similar when the gaps occur in approximately the same place, for example such that at least 75%, 80%, 85%, 90% or 95% of a gap in a first layer overlaps with a gap in the second layer. In other words, the gaps 404c, 406c and 408c may at least partially overlap each other. In some cases, one of the gaps may be overlapped by respective gaps in a plurality of other layers. This is the case in Figure 4, in which the gap 404c in the first layer 404’ is overlapped by the gaps 406c, 408c, in the second and third layers 406’, 408’. Creating stepped edges for the layers may reduce the likelihood of a short circuit or other defects down the sides of the layers. As explained above, the speed of the mask 130 may be linked to the speed of the substrate, in order to create synchronised gaps in the successive layers deposited on the substrate, such that the successive layers have stepped edges. Furthermore, creating gaps between the layers creates smaller layers so that the capacity of the smaller stack may not cause a thermal mn-away in the event of a short circuit.

In some examples, there may be one or more masks on the mask transport system 152a- 152d. Each mask on the mask transport system may be the same or similar sizes or different sizes. For example, the mask transport system 152a- 152d may move three masks at substantially the same speed as the speed of the substrate as moved by the conveyor system. The speed of the mask may be considered to be substantially the same as the speed of the substrate when the speed of the mask is approximately equal to the speed of the substrate, as described above. A first mask, smaller than a second mask and a third mask, may be used to create a first gap 404c in the first layer 404’. The second mask, larger than the first mask but smaller than the third mask, may be used to create a second gap 406c in the second layer 406’. As the second mask is larger than the first mask, the second gap 406c is larger than the first gap 404c. Similarly, the third mask, larger than the first mask and the second mask, may be used to create a third gap 408c in the third layer 408’. As the third mask is larger than the second mask, the third gap 408c is larger than the second gap 406c. This for example allows layers with different sized gaps to be deposited in a continuous manner, or with fewer breaks or pauses in deposition than otherwise. This can improve the efficiency of deposition of the layers.

In other examples, the mask transport system 152a-152d may move one or more masks, where each mask is a different size. The masks of different sizes may be used to create gaps of different sizes in a single layer on a substrate. For example, a first mask, smaller than a second mask and a third mask, may be used to create a first gap in a layer. The second mask, larger than the first mask but smaller than the third mask, may be used to create a second gap in the layer. As the second mask is larger than the first mask, the second gap is larger than the first gap. Similarly, the third mask, larger than the first mask and the second mask, may be used to create a third gap in the layer. As the third mask is larger than the second mask, the third gap is larger than the second gap. This also for example allows a layer with different sized gaps to be deposited in a continuous manner, or with fewer breaks or pauses in deposition than otherwise. This can improve the efficiency of deposition of the layer.

In some examples, there may be a space between the mask 130 and the substrate 402 or the most recently-deposited layer on the substrate 402. In Figure 4 for example, although not drawn to scale, there is a space between the mask 130 and the substrate 402 with the first and second layers 404’, 406’ when the third layer 408’ is deposited. The space between the mask 130 and the substrate 402 may be a fraction of a millimetre to several millimetres. In some examples, the space between the mask 130 and the substrate 402 may be tens of millimetres. For layers 404’, 406’, 408’ with more distinct edges e.g. sharp and accurate, the space between the mask 130 and substrate 402 may be reduced. For example, the space between the mask 130 and the substrate 402 may be within 0.5 mm.

In other examples, there is no space between the mask 130 and the substrate 402 or the most-recently deposited layer on the substrate 402. The mask 130 and the substrate 402 may be in physical contact during the deposition process. For example, the mask 130 may be in physical contact with the second layer 406’ while the third material 408d is being deposited to create the third layer 408’. In such examples, there may be a plurality of masks of different sizes that are used to create gaps in the layers, where each layer has a different sized gap corresponding to the size of the mask used. In some examples, the direction of the mask may be substantially parallel to the direction of the substrate. For example, the mask and the substrate may move in the same direction as each other, as shown in Figure 4. A direction may be considered to be substantially parallel to the direction of the substrate where the direction is approximately parallel to the direction of the substrate, such as within measurement tolerances or with an angular deviation of within plus or minus 5, 10 or 20 degrees from parallel.

In some examples, the direction of the mask may be substantially perpendicular to the direction of the substrate. A direction may be considered to be substantially perpendicular to the direction of the substrate where the direction is approximately perpendicular to the direction of the substrate, such as within measurement tolerances or with an angular deviation of within plus or minus 5, 10 or 20 degrees from perpendicular. For example, the substrate may move in one direction and the mask may move at right angles to the direction of the substrate.

In other examples, the direction of the substrate may be a combination of a perpendicular and parallel direction to the direction of the mask. For example, the mask may move in a diagonal movement across the substrate.

In Figure 4, the mask 130 is represented as a rectangular mask which blocks deposition of material along the length of the mask (i.e. across the page, as shown) and along the width of the substrate (i.e. into the page, not shown). However, this is merely an example and other shapes or forms of mask may be used in other cases.

In some examples, the mask may be an elongate structure, such as a wire. The wire may be moved relative to the substrate in order to create a narrow gap in the layer on the substrate. For example, the length of the gap in the layer on the substrate may be substantially the same as the diameter of the wire. Different diameters, or thicknesses, of wire may be selected based on the required length of the gap.

In some examples, the wire may be stored on a wire reel. The wire may be unwound from the wire reel as the wire is moved by the mask transport system. In some examples, the wire may be unwound from the wire reel in one direction and the wire may be moved by the mask transport system in another direction e.g. the wire may be unwound perpendicular to the direction of travel of the substrate and the wire may be moved by the mask transport system parallel to the direction of travel of the substrate. In some examples, the wire may be first wound around a first wire reel, gradually unwound from the first wire reel in order for wire to act as a mask in the deposition zone 140, and then wire may be wound around a second wire reel. The second wire reel may then be removed at the end of the deposition process. Replacing the wire reel at the end of each deposition process may make the deposition process more efficient, as the wire would not have to be cleaned after each process.

Figure 5 is a schematic diagram of a deposition system 500 according to another example. Figure 5 is similar to Figure 4 except that, in Figure 5, the mask transport system comprises a barrel 160. In Figure 5, the deposition source 120 is at the centre of rotation of the barrel 160. The mask transport system may comprise one or more masks 130a, 130b, 130c which rotate around the centre of rotation of the barrel 160. The barrel 160 may comprise an outer surface with one or more holes cut into the outer surface, whereby the sections of the outer surface that remain act as one or more masks 130a, 130b, 130c. In other words, the remaining sections correspond to one or more masks 130a, 130b, 130c to inhibit the deposition of the material 508d on the substrate 502 and the holes in the barrel 160 let the material 508d though in order to be deposited. The barrel 160 may rotate at an angular velocity as indicated by the arrow 134c. The mask transport system of Figure 5 illustrates multiple masks 130a, 130b, 130c with increasing size.

As described in relation to Figure 4, the smallest mask 130a may be used when a first layer 504’ is deposited. The medium mask 130b may be used when a second layer 506’ is deposited. The largest mask 130c may be used when a third layer 508’ is deposited. In such an example, layers 504’, 506’, 508’ with stepped edges are created.

The layers 504’, 506’, 508’ are for example non-continuous layers, such as the non-continuous first electrode layer 104’, the non-continuous electrolyte layer 106’ and the non-continuous second electrode layer 108’ of Figure la, although this is merely an example. Features of Figure 5 which are similar to corresponding features of Figures la and lb are labelled with the same reference numeral but incremented by 400.

In other examples, not shown here, the mask transport system 160 may comprise one or more masks with the same or substantially similar sizes. The sizes of the masks may be considered to be substantially similar when the sizes of the masks are approximately equal, such as within measurement tolerances or with a size deviation of within plus or minus 1, 5 or 10 percent. In order to create stepped edges for the layers 504’, 506’, 508’, the angular velocity of the mask transport system (i.e. the speed of rotation) may be increased or decreased depending on which layer is being deposited. For example, for deposition of the first layer, a first angular velocity would be used. For deposition of the second layer, a second angular velocity would be used, which is faster than the first angular velocity. Finally, for deposition of the third layer, a third angular velocity would be used, which is faster than the second angular velocity.

Figure 6a to 6d are schematic diagrams illustrating masks and their resulting deposition patterns according to examples. There may be a variety of different configurations of masks or shutters that may be used to create non-continuous layers on a substrate. Two such examples are illustrated in Figures 6a and 6c, respectively. The deposition patterns resulting from their use are illustrated in Figures 6b and 6d, respectively.

Figure 6a shows a schematic diagram of masks 130a, 130b and a substrate 602, as seen from the perspective of a deposition source. The two masks 130a and 130b are over substrate 602, blocking part of the substrate 602 from the view of the deposition source, and hence blocking the deposition of the material. In this example, each mask is separate from each other mask e.g. not connected to each other. Such masks may be configured on the mask transport system, as described in relation to Figures 4 and 5.

In some examples, each mask may be arranged on the mask transport system using wires 170a, 170b. The wires 170a, 170b may be attached to each mask and arranged to move the masks on the mask transport system in the direction of transport. In some examples, the wires 170a, 170b may be configured to be thin enough such that the presence of the wires 170a, 170b in the deposition zone does not affect the deposition of the material on the substrate. In other examples, the wires 170a, 170b may be configured such that the wires 170a, 170b do affect the deposition of the material on the substrate, effectively acting as another mask when the wires 170a, 170b are in the deposition zone. In other cases, a distance between the wires 170a, 170b may be larger than a width of the deposition zone, such that the wires 170a, 170b do not overlap or otherwise pass through the deposition zone.

Figure 6b shows a schematic diagram of the resulting deposition pattern on the substrate 602 as a result of using the mask and substrate configuration given in Figure 6a. The mask 130a creates a gap 608c in the deposition of the material to create a layer 608’ which includes a first portion 608a and a second portion 608b. Such a deposition pattern may be repeated with the use of mask 130b to create another gap in the deposition of the material to create another layer.

Figure 6c shows a schematic diagram of a mask 130d and a substrate 602, again seen from the perspective of a deposition source. The mask 130d is over substrate 502, blocking part of the substrate 602 from the view of the deposition source, and hence blocking the deposition of the material. In this example, the mask 130d is a continuous arrangement of masks i.e. the individual masks 130a and 130b of Figure 6a are connected together to form a continuous arrangement of masks. The continuous arrangement of masks may be described as a mask belt. Such a continuous arrangement of masks may be configured on the mask transport systems of Figure 4 or Figure 5, creating a continual loop of masks around the deposition source, which may be moved by the mask transport system.

Figure 6d shows a schematic diagram of the resulting deposition pattern on the substrate as a result of using the mask and substrate configuration given in Figure 6c. Similar to Figure 6b, the continual mask 130d creates a gap 608c in the deposition of the material to create a layer 608’ which includes a first portion 608a and a second portion 608b. The deposition pattern is repeated due to the presence of the mask 130d to create another gap in the deposition of the material. In addition to the gaps created by the mask within the layer 608’ etc, in some examples there is a gap between the top edge of the substrate 602 and the layer 608’ and there is a gap between the bottom edge of the substrate 602 and the layer 608’, due to the connection 130e between the masks. In other examples, the substrate 602 may be smaller in width than the continual mask 130d such that the top edge of the substrate 602 and the bottom edge of the substrate 602 do not overlap the connection 130e between the masks. As a result, the connection 130e between the masks is not between the deposition source and the deposition zone and therefore does not affect the resulting deposition pattern. In such an example, the resulting deposition pattern on the substrate may look similar to the deposition pattern on Figure 6b.

Figure 7 is a schematic diagram of a deposition system according to another example. The deposition system 700 of Figure 7 is similar to the deposition system 400 of Figure 4. However, in addition to the deposition system 400 of Figure 4, there is a cleaning system 162 in the deposition system 700 of Figure 7. Features of Figure 7 which are similar to corresponding features of Figure 4 are labelled with the same reference numerals but incremented by 300; corresponding descriptions are to be taken to apply.

In some examples, the cleaning system 162 is integrated into the mask transport system 152a-152d so that the one or more masks 130 may be cleaned as they are transported around the mask transport system 152a- 152d. For example, in Figure 7, the cleaning system 162 is integrated into the mask transport system 152a-152d such that each of the masks 130 are cleaned as they are transported around the mask transport system 152a- 152d. The cleaning system 162 may be independent from the mask transport system 152a- 152d such that the cleaning system 162 may be installed and/or uninstalled from the mask transport system 152a-152d without affecting the function of the mask transport system 152a-152d to transport the masks.

In other examples, the cleaning system 162 may be on a separate system to that of the mask transport system 152a-152d. While not shown in Figure 7, the cleaning system 162 may be installed separately to the mask transport system 152a- 152d so that the masks may be transported from the mask transport system 152a-152d to the cleaning system 162 and back again, once the masks have been cleaned. In such an example, the masks may not be transported to the cleaning system 162 every time they are transported around the mask transport system 152a- 152d, but instead only transported to the cleaning system 162 on every nth transportation around the mask transport system 152a- 152d or when the masks need cleaning.

In some examples, the cleaning system 162 may clean the mask by physical abrasion. The cleaning system 162 may comprise a brush that moves across the mask to remove the material deposited on the mask by the deposition process. In other examples, the cleaning system may clean the mask by laser ablation. The cleaning system 162 may comprise a laser system. The laser system may emit a laser beam that impinges on the surface of the mask and ablates the material deposited on the mask.

Due to the mask 130 blocking the deposition of first, second and third material 704d, 706d, 708d onto the substrate 702, and thus creating first, second and third layers 704’, 706’, 708’, there may be a build-up of material on the mask itself. Figure 7 shows that an amount of the material 708d to be deposited on the substrate 702 is collected on the mask 130 too, as shown by collected material 708e on the mask 130. As the amount of collected material 708e on the mask increases, the edges of the gaps 702c, 706c, 708c may become less distinct, e.g. less sharp and accurate. In such a scenario, this may cause an increase in the likelihood of short circuits or other defects between the layers on the substrate. Therefore, cleaning the mask 130 regularly, to decrease or remove the collected material 708e may help to reduce this effect.

The mask transport system 152a- 152d may move the mask 130, with its collected material 708e, through a cleaning system 162. When the mask 130 exits the cleaning system 162, the mask is clean and no longer has collected material 708e on it. The mask transport system may then move the mask 130 so that the mask 130 is once again above the deposition source 120, in the same place as it started.

Figure 8 is a flow diagram 800 illustrating a method of creating a layer on a substrate. The method may be implemented using the systems described above.

In block 810 of the flow diagram 800, a substrate is moved relative to a deposition zone, wherein the deposition zone comprises a material to be deposited on the substrate.

In block 820 of the flow diagram 800, a mask is moved between the substrate and a deposition source for providing the material. The mask is moved from a first side of the deposition zone to a second side of the deposition zone, wherein the second side of the deposition zone is different from the first side of the deposition zone. The substrate may be moved at a first speed and the mask may be moved at a second speed.

In some examples, the second speed of the mask is different from the first speed of the substrate. In other examples, the second speed of the mask is the same or substantially similar to the first speed of the substrate.

In some examples, the substrate may be moved by a conveyor system, operable to move the substrate in a first direction. Similarly, the mask may be moved by a mask transport system, operable to move the mask in a second direction. In some examples, the first direction of the substrate may be substantially parallel to the second direction of the mask. For example, the substrate and the mask may move in the same direction as each other. In other examples, the first direction of the substrate may be substantially perpendicular to the second direction of the mask. For example, the substrate may move in one direction and the mask may move at right angles to the direction of movement of the substrate.

In some examples, the conveyor system may be a roll-to-roll system. In some examples, the mask transport system may be a roll-to-roll system. In such a way, a pattern material on a substrate may be created in an efficient manner.

In other examples, the mask transport system may be a barrel system where the deposition source is at the centre of rotation of the barrel system.

In some examples, the mask transport system is arranged to move the mask from the second side of the deposition zone back to the first side of the deposition zone by moving beneath the deposition source. The mask transport system may be a continual loop system whereby moving the mask around the continual loop system brings the mask back to where it started.

In some examples, the mask transport system is arranged to move a plurality of masks. Each mask of the plurality of masks may be substantially the same size or different sizes. In some examples, each mask of the plurality of masks are attached together in a continual loop, creating a continuous arrangement of masks. The continuous arrangement of masks may be moved by the mask transport system in a continual loop.

In some examples, the conveyor system and the mask transport system are arranged such that there is a space between the mask and the substrate, e.g. such that there is no physical contact between the mask and the substrate. In other examples, the conveyor system and the mask transport system are arranged such that there is no space between the mask and the substrate, e.g. such that there is physical contact between the mask and the substrate. Such an arrangement may occur throughout the movement of the mask and the substrate or only when the mask and the substrate are in the vicinity of the deposition zone.

In some examples, the material deposited on the substrate creates a layer of material on the substrate. The arrangement of the mask between the deposition source and the substrate creates a gap in the layer. The layer with the gap, caused by the mask, may be considered to be a non-continuous layer.

In some examples, a first material is deposited on the substrate to creates a first layer with a first gap. In further examples, a second material may be deposited on the first layer to create a second layer with a second gap. In further examples, a third material may be deposited on the second layer to create a third layer with a third gap.

In some examples, the first speed of the substrate may be substantially equal to the second speed of the mask when the first material is deposited on the substrate. Furthermore, the first speed of the substrate may be different from the second speed of the mask when the second material is deposited on the first layer on the substrate. When the second material is deposited when the second speed of the mask is slower than the first speed of the substrate, a second gap in the second layer is created which is larger than the first gap in the first layer.

In some examples, the first speed of the substrate may be configured to be different from the second speed of the mask by keeping the first speed constant and changing the second speed. Alternatively, the first speed of the substrate may be configured to be different from the second speed of the mask by keeping the second speed constant and changing the first speed.

In some examples, the mask transport system may comprise a separate cleaning system to clean the mask. The cleaning system may be on a separate system to that of the mask transport system. Alternatively, the cleaning system may be integrated into the mask transport system so that the mask may be cleaned as it is transported around the mask transport system.

In some examples, the mask may comprise a wire.

In some examples, the deposition source is a vapour deposition source. In further examples, the vapour deposition source is a thermal deposition source. In other examples, the vapour deposition source is a sputter deposition source.

In some examples, the deposition system is for manufacturing an energy storage device. The energy storage device may be a solid-state cell. In such examples, the first material deposited on the substrate is for a first electrode layer, e.g. a cathode layer. The second material deposited on the first electrode layer on the substrate is for an electrolyte layer. The third material deposited on the electrolyte layer on the substrate is for a second electrode layer, e.g. an anode layer. Creating a cell with a smaller surface area as part of the deposition process, may reduce the capacity of the cell and reduce the risk of a thermal run-away in the event of a short circuit. The above examples are to be understood as illustrative examples. Further examples are envisaged. For example, it is to be appreciated that the methods or systems herein may be used to provide a plurality of non-continuous layers on a substrate without stepped edges. In such cases, a gap through a plurality of such layers may have substantially straight sides, such as straight or otherwise planar within manufacturing or measurement tolerances. For example, the edges of the gap in each layer may be aligned with each other. The methods or systems herein may therefore be used flexibly to create layer(s) on a substrate with a variety of different configurations.

It is to be understood that any feature described in relation to any one example may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the examples, or any combination of any other of the examples. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the accompanying claims.