TECHNICAL FIELD

[0001] The present disclosure relates to processing of substrates, particular thin flat substrates. In particular, embodiments described herein relate to a mask arrangement for carrying a mask and a substrate to be processed, a method for aligning a mask to a substrate, and an apparatus for processing a masked substrate. More particularly, embodiments of the present disclosure relate to a mask arrangement for carrying a masked thin or ultra-thin substrate, a method for aligning a mask to thin or ultra-thin substrate, and an apparatus for processing a masked thin or ultra-thin substrate.

BACKGROUND

[0002] Techniques for layer deposition on a substrate include, for example, thermal evaporation, chemical vapor deposition (CVD) and physical vapor deposition (PVD) such as sputtering deposition. A sputter deposition process can be used to deposit a material layer on the substrate, such as a layer of an insulating material. During the sputter deposition process, a target having a target material to be deposited on the substrate is bombarded with ions generated in a plasma region to dislodge atoms of the target material from a surface of the target. The dislodged atoms can form the material layer on the substrate. In a reactive sputter deposition process, the dislodged atoms can react with a gas in the plasma region, for example, nitrogen or oxygen, to form an oxide, a nitride or an oxinitride of the target material on the substrate.

[0001] Coated materials can be used in several applications and in several technical fields. For instance, coated materials may be used in the field of microelectronics, such as for generating semiconductor devices. Also, substrates for displays can be coated using a PVD process. Further applications include insulating panels, organic light emitting diode (OLED) panels, substrates with thin film transistors (TFTs), color filters, thin film batteries or the like. [0002] The tendency toward larger and also thinner substrates can result in bulging of the substrates due to stress applied to the substrate, e.g., during a deposition process. Support systems which hold a substrate during a deposition process introduce bulging on the substrate, e.g., due to forces that push the substrate edge towards the center of the substrate. Bulging can, in turn, cause problems due to the increasing likelihood of breakage. Accordingly, there is a need to reduce bulging and to support bigger and thinner substrates without damage or breakage.

SUMMARY

[0003] In view of the above, a mask arrangement for masking a substrate during deposition in a processing chamber and a method for aligning a mask to a substrate according to the independent claims are provided. Further advantages, features, aspects and details are apparent from the dependent claims, the description and drawings.

[0004] According to one aspect of the present disclosure, a mask arrangement for masking a substrate during deposition in a processing chamber is provided. The mask arrangement includes a first plate having a first surface for supporting the substrate and a second plate for holding a mask. The mask has at least one opening and is arranged between the substrate and the second plate. The first plate includes a first pin and a second pin protruding from the first surface. The first pin is arranged to delimitate a movement of the substrate in a first direction. The second pin is arranged to delimitate a movement of the substrate in a second direction different from the first direction. The mask includes a first hole for receiving the first pin and second hole for receiving the second pin. The first hole is configured for allowing a movement of the mask relative to the first plate in the second direction. The second hole is configured for allowing a movement of the mask relative to the first plate in the first direction.

[0005] According to another aspect of the present disclosure, a mask arrangement for masking a substrate during deposition in a processing chamber is provided. The mask arrangement includes a first plate having a first surface for supporting the substrate and a second plate for holding a mask. The mask has at least one opening and is arranged between the substrate and the second plate. The first plate includes a first pin and a second pin protruding from the first surface, wherein the first pin is arranged to delimitate a movement of the substrate in a first direction, and wherein the second pin is arranged to delimitate a movement of the substrate in a second direction different from the first direction. The mask includes a first hole for receiving the first pin and second hole for receiving the second pin. The first hole is configured for allowing a movement of the mask relative to the first plate in the second direction. The second hole is configured for allowing a movement of the mask relative to the first plate in the first direction. The first surface of the first plate is oriented approximately parallel to the direction of gravity. The first direction is approximately parallel to the direction of gravity. The second direction is perpendicular to the first direction. Further, a first flat spring element and a second flat spring element are provided between the second plate and the mask. The first flat spring element and the second flat spring element are arranged in a crossed manner for applying a contact pressure to a central portion of the mask. The first flat spring element and the second flat spring element are received within a recess provided at an edge of an aperture of the second plate facing the mask.

[0006] According to a further aspect of the present disclosure, an apparatus for depositing a layer on a substrate is provided. The apparatus includes a processing chamber adapted for layer deposition therein; a deposition source for depositing material forming the layer; and a mask arrangement within the processing chamber. The mask arrangement of the apparatus includes a first plate having a first surface for supporting the substrate and a second plate for holding a mask, wherein the mask has at least one opening and is arranged between the substrate and the second plate. The first plate of the mask arrangement includes a first pin and a second pin protruding from the first surface, wherein the first pin is arranged to delimitate a movement of the substrate in a first direction and wherein the second pin is arranged to delimitate a movement of the substrate in a second direction different from the first direction. The mask includes a first hole for receiving the first pin and a second hole for receiving the second pin, wherein the first hole is configured for allowing a movement of the mask relative to the first plate in the second direction, and wherein the second hole is configured for allowing a movement of the mask relative to the first plate in the first direction. [0007] According to a yet further aspect of the present disclosure, an apparatus for depositing a layer on a substrate is provided, wherein the apparatus includes a processing chamber adapted for layer deposition therein; a deposition source for depositing material forming the layer; and a mask arrangement according to any of the embodiments described herein within the processing chamber.

[0008] According to another aspect of the present disclosure, a method for aligning a mask to a substrate is provided. The method includes arranging the substrate on a first surface of a first plate such that the substrate is in contact with a first pin and a second pin protruding from the first surface. The first pin is arranged to delimitate a movement of the substrate in a first direction and the second pin is arranged to delimitate a movement of the substrate in a second direction, wherein the second direction is different from the first direction. Further the method includes mounting the mask on top of the substrate such that the first pin is received within a first hole of the mask and the second pin is received within a second hole of the mask. The first hole is configured for allowing a movement of the mask relative to the first plate in the second direction and the second hole is configured for allowing a movement of the mask relative to the first plate in the first direction. Further the method includes holding the substrate and the mask in between the first plate and a second plate. [0009] The disclosure is also directed to an apparatus for carrying out the disclosed methods including apparatus parts for performing the methods. The method may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, the disclosure is also directed to operating methods of the described apparatus. It includes a method for carrying out every function of the apparatus. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described in the following:

FIG. 1A shows a schematic front view of a mask arrangement according to embodiments described herein;

FIG. IB shows a schematic cross sectional view of the mask arrangement as shown in FIG. 1A;

FIG. 2A shows a schematic front view of a mask arrangement according to embodiments described herein, having at least one magnetic element for holding the mask;

FIG. 2B shows a schematic cross sectional view of the mask arrangement as shown in FIG. 2A;

FIG. 3A shows a schematic front view of a mask arrangement according to further embodiments described herein, having a spring element configured for applying a contact pressure to a central portion of the mask;

FIG. 3B shows a schematic cross sectional view of the mask arrangement as shown in FIG. 3A;

FIG. 4A shows a schematic front view of a mask arrangement according to other embodiments described herein, having a spring element configured for applying a contact pressure to a central portion of the mask;

FIG. 4B shows a schematic cross sectional view of the mask arrangement as shown in FIG. 4A;

FIG. 5 shows a schematic top view of an apparatus for depositing a layer on a substrate according to embodiments described herein; FIG. 6 shows a block diagram illustrating a method for aligning a mask to a substrate according to embodiments described herein; and

FIG. 7 shows a block diagram illustrating a method for aligning a mask to a substrate according to further embodiments described herein. DETAILED DESCRIPTION OF THE DRAWINGS

[0011] Reference will now be made in detail to the various embodiments of the disclosure, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. In the following, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the disclosure and is not meant as a limitation of the disclosure. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations. [0012] In the present disclosure, the term "mask arrangement" may be apprehended as an arrangement including a mask for masking a substrate. In particular, a "mask arrangement" as described herein may be understood as an arrangement which is configured for holding a mask pressed onto a substrate surface to be processed. More particularly, a "mask arrangement" as described herein may be understood as a carrier for holding a substrate and a mask in which the substrate and the mask are arranged or packed into a sandwich-like arrangement in between a first plate, e.g. a base plate, and a second plate, e.g. a front plate.

[0013] In the present disclosure, the term "substrate" shall particularly embrace inflexible substrates, e.g., glass plates and metal plates. However, the present disclosure is not limited thereto and the term "substrate" can also embrace flexible substrates such as a web or a foil. According to some embodiments, the substrate can be made of any material suitable for material deposition. For instance, the substrate can be made of a material selected from the group consisting of glass (for instance soda-lime glass or borosilicate glass), metal, polymer, ceramic, compound materials, carbon fiber materials, mica or any other material or combination of materials which can be coated by a deposition process. Further, it is to be understood that the substrate may later be cut into a number of smaller pieces, for example for use in thin film battery applications.

[0014] In the following, embodiments are described which refer inter alia to a mask arrangement that permits the holding of thin substrates such as, but not limited to, PET substrates (PET: polyethylene terephthalate), glass and yttria stabilized zirconia (YSZ). For instance, the mask arrangement according to embodiments described herein may be used for thin sheets or substrates having a thickness in a range from 0.02 mm to 0.2 mm. In particular, the mask arrangement according to embodiments described herein is configured to be used for ultra-thin substrates (UTS) having a thickness of 0.05 mm or less, e.g. 0.02 mm or 0.04 mm. The substrate carrier arrangement may be used in glass pane machines designed for glass panes having a thickness in a range from 0.3 mm to 1.1 mm. The thin substrates to be processed may include plastic or thin glass substrates. PET plastic sheets may be used for anti-reflective applications in mobile devices, such as mobile phones, tablet computers, e.g. as thin displays.

[0015] According to another typical embodiment described herein, which may be combined with other embodiments described herein, the area size of the substrates to be processed may be in a range from 100 mm x 130 mm to 300 mm x 500 mm. For example, the area size of the substrates to be processed can be 125 mm x 145 mm or 210 mm x 297 mm.

[0016] In the present disclosure, the term "mask" may be understood as a thin plate having at least one opening. Typically, the "mask" as described herein may have a thickness of 0.2 mm or less. In particular, the "mask" as described herein may be employed to cover areas of a substrate which shall not be processed, e.g. not be coated. For instance, the "mask" as described herein may be made of at least one material selected from the group consisting of: LiCO, A1 ₂ 0 ₂ , YSZ, AlTiC, glass D263T, stainless steel, Ti, Macor, and Invar e.g. with approx 30% or 80% Ni.

[0017] In the present disclosure, the term "pin" may be understood as an element configured to hold or support a substrate as described herein. A "pin" as described may have any kind of cross-section. For example, the cross-section of the pin may be rectangular, square, round, circular or may have any other suitable shape. Typically, a "pin" as described herein may have a diameter from 2 mm to 10 mm. For instance, the diameter of the pin may be 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm or 9 mm.

[0018] FIG. 1A shows a schematic front view of a mask arrangement according to embodiments described herein. The mask arrangement 100 for masking a substrate 10 during deposition in a processing chamber includes a first plate 110 having a first surface 101 for supporting the substrate 10 and a second plate 120 for holding a mask 130, as exemplarily shown in FIGS. 1A and IB. The mask 130 has at least one opening and is arranged between the substrate 10 and the second plate 120. Further, the first plate 110 includes a first pin 111 and a second pin 112 protruding from the first surface 101. The first pin 111 is arranged to delimitate a movement of the substrate in a first direction 141 and the second pin 112 is arranged to delimitate a movement of the substrate in a second direction 142 different from the first direction 141. [0019] With exemplarily reference to FIG. 1A, according to embodiments described herein the mask 130 includes a first hole 131 for receiving the first pin 111 and second hole 132 for receiving the second pin 112. The first hole 131 is configured for allowing a movement of the mask relative to the first plate 110 in the second direction 142 and the second hole 132 is configured for allowing a movement of the mask 130 relative to the first plate 110 in the first direction 141. Accordingly, beneficially, a mask arrangement can be provided in which any difference in thermal expansion between the mask and the first plate can be equalized such that the substrate and the mask remain properly aligned to each other, particularly throughout the deposition process in which the temperature may vary. With exemplarily reference to FIGS. 1A and IB, it is to be understood that the position of the mask may be fixed relative to the first plate with the same pins as the position of the substrate relative to the first plate. Accordingly, an alignment of the substrate and mask to each other can be ensured.

[0020] According to embodiments which can be combined with other embodiments described herein, the first plate 110 may be a base plate for supporting the substrate 10. The second plate 120 may be a front plate which may be arranged to face a deposition direction 115, as exemplarily shown in FIG. IB. In particular, it is to be understood that the first plate 110 and the second plate 120, e.g. the base plate and the front plate, are arranged to prevent the substrate 10, particularly the substrate 10 being a thin substrate, from collapsing. Accordingly, embodiments of the mask arrangement as described herein may be considered as a carrier for holding a substrate and a mask in which the substrate and the mask are arranged or packed into a sandwich-like arrangement in between the first plate, e.g. the base plate, and the second plate, e.g. the front plate.

[0021] With exemplarily reference to FIG. IB, according to embodiments which can be combined with other embodiment described herein, the first plate 110, e.g. the base plate, may be thicker than the second plate 120, e.g. the front plate. For example, the first plate 110 may have a thickness of 5 mm - 15 mm, e.g. 10 mm. The first plate, i.e. the base plate, may be a solid plate or may have one or more openings as exemplarily shown in FIG. IB. A base plate having one or more openings may be beneficial either for better cooling or for better heating of the substrate, e.g. from the backside of the base plate, i.e. the side of the base plate not contacting the substrate. For example, the backside of the base plate may be heated by a radiation heater.

[0022] According to embodiments which can be combined with other embodiments described herein, the second plate 120, i.e. the front plate, may have an inner aperture which is much bigger compared to a maximum substrate coating window which may be provided by the mask, as exemplarily shown in FIG. IB. It is to be understood that the second plate 120 is configured to hold or fix the substrate, particularly a thin substrate, and the mask by pressing the mask and the substrate against the first plate 110, i.e. the base plate. For example, the mask and the substrate in between the first plate and the second plate, e.g. the sandwich-like arrangement of the mask and the substrate in between the first plate and the second plate, may be fixed together via fixation elements, e.g. a set of screws and/or via clamps (e.g. spring forced clamps) (not shown). In particular, the fixation elements may be provided at the outside rims of the first plate and/or the second plate.

[0023] With exemplarily reference to FIGS. 1A and IB, it is to be understood that the first plate 110, i.e. the base plate, may be the main carrier plate for the substrate 10. Alternatively, first plate 110 may be a sub-carrier plate of an arrangement of two or more subcarriers. For example, each sub-carrier plate of an arrangement of two or more sub-carrier plates may hold one substrate. The two or more sub-carrier plates may be attached to a main carrier plate. Accordingly, it is to be understood that the mask arrangement according to embodiments described herein, can be used as a main carrier and/or as sub-carrier. For example, two or more mask arrangements as described herein may be attached to a main carrier plate. Such a sub-carrier concept may ease the substrate exchange and/or the pre assembly and/or the alignment of the substrate and the mask.

[0024] According to some implementations, the mask arrangement can be configured for supporting a substrate having a size of DIN A5, A4, or A3. According to some implementations, the embodiments described herein can be utilized for sputter deposition on large area substrates, e.g., for lithium battery manufacturing or electrochromic windows. As an example, one or more thin film batteries can be formed on a large area substrate arranged within the mask arrangement according to the embodiments described herein. According to some embodiments, a large area substrate can be GEN 4.5, which corresponds to about 0.67 m ² substrates (0.73x0.92m), GEN 5, which corresponds to about 1.4 m ² substrates (1.1 m x 1.3 m), GEN 7.5, which corresponds to about 4.29 m ² substrates (1.95 m x 2.2 m), GEN 8.5, which corresponds to about 5.7m ² substrates (2.2 m x 2.5 m), or even GEN 10, which corresponds to about 8.7 m ² substrates (2.85 m x 3.05 m). Even larger generations such as GEN 11 and GEN 12 and corresponding substrate areas can similarly be implemented.

[0025] It is to be understood that the embodiments described herein can be used in the manufacture of, for example, thin film batteries, electrochromic windows and displays, for example, liquid crystal displays (LCD), PDPs (Plasma Display Panel), organic light-emitting diode (OLED) displays, and the like.

[0026] With exemplary reference to FIGS. 1A and IB, it is to be understood that the major purpose of the mask 130 is to cover areas of the substrate 10 which shall not be coated. According to embodiments which can be combined with other embodiments described herein, the inner mask edges are configured to be sharp such that beneficially a sharp edge on the dividing line between coated and uncoated area can be achieved. In particular, the inner mask edges of the mask may have a thickness of less than 0.5 mm, particularly less than 0.3 mm, for example 0.2 mm or less, or even 0.1 mm or less. Accordingly, a sharp edge on the dividing line between a coated and an uncoated area on the substrate can be achieved. Further, it is to be understood that alternatively the complete mask may have a thickness of less than 0.5 mm, particularly less than 0.3 mm, for example 0.2 mm or less, or even 0.1 mm or less.

[0027] Further, with exemplary reference to FIGS. 1A and IB, it is to be understood that the mask 130 of the mask arrangement as described herein is configured and arranged to prevent the substrate 10, particularly the substrate 10 being a thin substrate, from collapsing and falling off the first plate, e.g. the base plate. In the case that the first plate is be employed as a main carrier plate, the mask may have one big rectangular cut out and may mask the substrate rim only, e.g. by 1 mm to 5 mm. For larger substrate sizes prone to collapsing, the mask may have inside bars, e.g. cross-like inside bars, which stabilize the thin large substrate, as exemplarily shown in FIGS. 1A, 2 A, 3 A and 4 A. [0028] According to embodiments which can be combined with other embodiment described herein, the mask may be made of metal with a similar thermal expansion compared to the substrate material used. For example, the mask may be made of Titanium or Invar.

[0029] According to embodiments which can be combined with other embodiment described herein, the first surface 101 of the first plate 110 of the mask arrangement may be oriented approximately parallel to the direction of gravity. In particular, according to some embodiments the first direction 141 in which the first pin 111 delimitates a movement of the substrate may be approximately parallel to the direction of gravity. As exemplarily shown in FIGS. 1A, 2A, 3A and 4A, according to embodiments which can be combined with other embodiment described herein, a first edge 10A of the substrate 10 may be in contact with the first pin 111. Additionally, the first edge 10A of the substrate 10 may be in contact with a third pin 113 protruding from the first surface 101. Accordingly, the relative position of the substrate 10 to the first plate 110 may be fixed with respect to the first direction 141. [0030] With exemplarily reference to FIGS. 1A, 2 A, 3 A and 4 A, according to embodiments which can be combined with other embodiment described herein a second edge 10B of the substrate 10 may be in contact with the second pin 112. Accordingly, the relative position of the substrate 10 to the first plate 110 may be fixed with respect to the second direction 142.

[0031] Accordingly, it is to be understood that the first pin 111, the second pin 112 and the third pin 113 may also be referred to as alignment pins in order to align the substrate with respect to the first plate. Further, it is to be understood that the first pin 111, the second pin 112 and the third pin 113 are also employed for aligning the mask with respect to the substrate, as the first pin 111, the second pin 112 and the third pin 113 may be received within the first hole 131, the second hole 132, and the third hole 133 as described herein. According to embodiments which can be combined with other embodiment described herein, the alignment pins (e.g. the first pin 111, the second pin 112 and the third pin 113) may be fixed in the base plate (e.g. the first plate 110). For instance, e.g. two alignment pins (e.g. the first pin 111 and the third pin 113) may be provided on a bottom of the substrate (e.g. the first edge 10A of the substrate 10) and one further alignment pin may be provided on one side of the substrate (e.g. the second edge 10B of the substrate 10), as exemplarily shown in FIGS. 1A, 2 A, 3 A and 4 A. Accordingly, the substrate 10 may be put onto the two bottom alignment pins (i.e. the first pin 111 and the third pin 113) and be pushed against the single side pin (i.e. the second pin 112). Accordingly, a defined substrate position with respect to the first plate and/or the mask may be obtained.

[0032] According to some embodiments which can be combined with other embodiments described herein, the mask 130 has three holes (e.g. a first hole 131 for receiving the first pin 111, a second hole 132 for receiving the second pin 112, and a third hole 133 for receiving the third pin 113, as exemplarily shown in FIG. 1A. For example, the first hole 131 and the a second hole 132 may be slot holes. For instance, the first hole configured as slot hole may be a horizontal slot hole and the second hole 132 configured as a slot hole may be a vertical slot hole. The third hole 133 may be configured to be adapted to the outer dimension of the third pin. For example, in the case that the third pin is configured to be circular with a specific diameter, the third hole is also configured to be circular having a corresponding diameter. Accordingly, the relative position of the substrate and the mask with respect to the first plate may be fixed while at the same time any difference in thermal expansion between the mask and the first plate and/or between the substrate and mask can be equalized such that the substrate and mask remain properly aligned to each other, particularly throughout the deposition process in which the temperature may vary.

[0033] FIGS. 2 A and 2B show schematic views of a mask arrangement 100 according to embodiments described herein having at least one magnetic element 150 for holding the mask. In particular, the first plate 110 may include at least one magnetic element 150 for holding the mask 130. For example, as exemplarily shown in FIG. 2A, a central magnetic element 151 may be arranged at a center of the first plate 110. Additionally, further magnetic elements, such as a first magnetic element 152 and/or a second magnetic element 153 and/or a third magnetic element 154 and/or a fourth magnetic element 155 may be provided. [0034] For example, the central magnetic element 151, the first magnetic element 152, the second magnetic element 153, the third magnetic element 154 and the fourth magnetic element 155 may be arranged on or within a cross bar of the first plate, as exemplarily shown in FIG. 2A. According to a typical implementation, the first magnetic element 152, the second magnetic element 153, the third magnetic element 154 and the fourth magnetic element 155 may be equally spaced apart from the central magnetic element 151, as exemplarily shown in FIG. 2A. Accordingly, it is to be understood that one or more magnetic element(s) may beneficially be arranged on or within the first plate, e.g. the base plate, such that the one or more magnetic element(s) may pull the mask 130 against the substrate 10. In other words, magnets may be fixed in the base plate behind the substrate in order to pull a magnetic mask, e.g. the mask 130 of the mask arrangement 100 as described herein, against the substrate 10. Accordingly, beneficially a mask arrangement may be provided with which a blurred coating layer on the substrate due to shadowing effects caused by a mask not firmly resting on the substrate can be reduced or even be avoided.

[0035] According to embodiments which can be combined with other embodiments described herein, the mask arrangement may include a spring element 160 configured for applying a contact pressure to a central portion of the mask 130. The spring element 160 may be provided between the second plate 120 and the mask 130, as exemplarily shown in FIGS. 3A and 3B. For example, the mask arrangement may include a first spring element 161 and a second spring element 162 which are provided between the second plate 120 and the mask 130. As exemplarily shown in FIG. 3 A, the first spring element 161 and the second spring element 162 may be arranged in a crossed manner such that a spring cross is provided for applying a contact pressure to a central portion of the mask 130. In particular, the first spring element 161 may be a first flat spring element and the second spring element 162 may be a second flat spring element which can be provided between the second plate 120 and the mask 130.

[0036] For example, the first flat spring element and/or the second flat spring element may be made of thin spring strip material, e.g. a strip of spring steel, having a thickness from 0.1 mm to 1 mm, e.g. 0.2 mm. The width of the first flat spring element and/or the second flat spring element may be from 5 mm to 10 mm. Accordingly, providing a first flat spring element and/or a second flat spring element having a thickness and/or a width as described herein may be beneficial in order to avoid or even eliminate shadowing effects caused by a mask not firmly resting on the substrate. [0037] Further, the first spring element 161, e.g. the first flat spring element, and/or the second spring element 162, e.g. the second flat spring element, may be pre-tensioned. Accordingly, beneficially the contact pressure provided by the first spring element 161 and/or the second spring element 162 to the central portion of the mask may be enhanced. [0038] With exemplarily reference to FIG. 3B, it is to be understood that by applying a pressing force to the central portion of the mask 130, the pressing force is also applied to the substrate 10 which is in contact with the mask. In particular, the contact pressure provided by the first spring element 161 and/or the second spring element 162 to the center portion of the mask may be transferred to a center portion of the substrate 10 as exemplarily shown in FIG. 3B. [0039] Accordingly, it is to be understood that embodiments of the mask arrangement as described herein, in which a spring element is provided for applying a contact pressure to a central portion of the mask, provide for firmly pressing the mask against the substrate such that a blurred coating layer on the substrate due to shadowing effects caused by a mask not firmly resting on the substrate can be avoided or even be substantially eliminated.

[0040] According to embodiments which can be combined with other embodiments described herein, the second plate 120 of the mask arrangement 100 may include an aperture 125 which is larger than the at least one opening of the mask 130. As exemplarily shown in FIGS. 3B and 4B, a first edge 121 of the aperture 125 of the second plate 120 facing a deposition direction 115 may be sloped, which may be beneficial for reducing or even avoiding shadowing effects such that the layer uniformity on the substrate is not affected. In other words, by providing the first edge of the aperture of the second plate with a slope, layer uniformity on the substrate during layer deposition can be improved.

[0041] Further, a second edge of the aperture 125 of the second plate 120 facing the mask 130 may have a recess 122 for holding a spring element, as exemplarily shown in FIGS. 3B and 4B. In particular, with exemplarily reference to FIG. 3B, the first spring element 161, e.g. the first flat spring element, and the second spring element 162, e.g. the second flat spring element, may be received within the recess 122 provided at an edge of the aperture 125 of the second plate 120. In particular, the edge of the aperture 125 of the second plate 120 at which the recess 122 may be provided faces the mask 130, as exemplarily shown in FIG. 3B. Accordingly, it is to be understood that the recess 122 may function as a pocket in which the first spring element 161 and/or the second spring element 162 may rest, such that beneficially a simple fixation of the first spring element 161 and/or the second spring element 162 can be provided.

[0042] According to embodiments which can be combined with other embodiment described herein, the mask arrangement 100 may be provided with a wire spring element 170 configured for applying a contact pressure to a central portion of the mask 130, as exemplarily shown in FIGS. 4A and 4B. In particular, the mask arrangement may include a first wire spring element 171 and a second wire spring element 172. For example, the first wire spring element 171 and the second wire spring element 172 may be arranged in a crossed manner, such that a spring cross is provided. Particularly, the first wire spring element 171 and the second wire spring element 172 may be arranged such that the intersection of the spring cross is provided at a central portion of the mask 130. For example, the wire spring element 170, e.g. the first wire spring element 171 and the second wire spring element 172, may be made of a thin wire having a diameter of 1 mm to 5 mm, in particular 2 mm to 4 mm. Accordingly, providing a first wire spring element and/or a second wire spring element having a diameter as described herein may be beneficial in order to avoid or even eliminate shadowing effects caused by a mask not firmly resting on the substrate.

[0043] According to some embodiments which can be combined with other embodiments described herein, the first wire spring element 171 and/or the second wire spring element 172 may be made of spring steel. Further, the first wire spring element 171 and/or the second wire spring element 172 may be pre-tensioned. Accordingly, beneficially the contact pressure provided by the first wire spring element 171 and/or the second wire spring element 172 to the central portion of the mask may be enhanced. It is to be understood that by applying a pressing force to the central portion of the mask 130, the pressing force is also applied to the substrate 10 which is in contact with the mask, as exemplarily shown in FIG. 4B. In particular, the contact pressure provided by the first wire spring element 171 and/or the second wire spring element 172 to the center portion of the mask may be transferred to a center portion of the substrate as exemplarily shown in FIG. 4B.

[0044] With exemplary reference to FIG. 4B, according to some embodiments which can be combined with other embodiments described herein, the end portions of the first wire spring element 171 and/or the second wire spring element 172 may rest in a pocket provided in the second plate 120, e.g. the front plate. In particular, the pocket may be a recess 122 provided at an edge of the aperture 125 of the second plate 120. Accordingly, a simple fixation of the first wire spring element 171 and/or the second wire spring element 172 may be provided. Further, as exemplarily shown in FIG. 4B, according to some embodiments the second wire spring element 172 may be arranged such that the second wire spring element 172 is substantially completely in contact with the mask. In this respect, it is to be noted that the expression "substantially completely in contact" is to be understood such that a contact of the second wire spring element 172 with the mask 130 is provided over substantially the complete length of the second wire spring element 172, particularly over at least 80% of the length of the second wire spring element 172, more particularly over at least 90% of the length of the second wire spring element 172. Accordingly, the second wire spring element 172 may be arranged in a flat manner, as exemplarily shown in FIG. 4B. The first wire spring element 171 may be provided on top of the second wire spring element 172, such that the first wire spring element 171 has a curved shape and presses the second wire spring element 172 onto the mask 130, as exemplarily shown in FIG. 4B. As a result, the mask may be pushed or pressed against the substrate in a simple and effective way.

[0045] FIG. 5 shows a schematic top view of an apparatus 200 for depositing a layer on a substrate according to embodiments described herein. According to some embodiments described herein, the apparatus 200 includes a processing chamber 210 adapted for layer deposition therein, a deposition source 220 for depositing material forming the layer; and a mask arrangement 100 within the processing chamber 210. The processing chamber 210 may be a vacuum chamber (also referred to as "deposition chamber" or "vacuum processing chamber"). The deposition source 220 may include one or more sputter deposition sources, such as a first sputter deposition source 230a and a second sputter deposition source 230b in the vacuum chamber. For example, the first sputter deposition source 230a and the second sputter deposition source 230b can be rotatable cathodes having targets of the material to be deposited on the substrate. [0046] According to embodiments of the apparatus 200 for depositing a layer on a substrate which can be combined with other embodiments described herein, the mask arrangement employed within the processing chamber 210 may be a mask arrangement according to any of the embodiments described herein. For example, the mask arrangement 100 employed in the apparatus 200 for depositing a layer on a substrate may include a first plate 110 having a first surface 101 for supporting the substrate 10 and a second plate 120 for holding a mask 130. The mask 130 of the mask arrangement 100 has at least one opening and is arranged between the substrate 10 and the second plate 120. The first plate 110 of the mask arrangement 100 may include a first pin 111 and a second pin 112 protruding from the first surface 101. In particular, the first pin 111 may be arranged to delimitate a movement of the substrate in a first direction 141 and the second pin 112 may be arranged to delimitate a movement of the substrate in a second direction 142 which is different from the first direction 141. As exemplarily described with reference to FIGS. 1A, 2 A, 3 A and 4 A, the mask 130 of the mask arrangement includes a first hole 131 for receiving the first pin 111 and a second hole 132 for receiving the second pin 112. In particular, the first hole 131 is configured for allowing a movement of the mask relative to the first plate 110 in the second direction 142 and the second hole 132 is configured for allowing a movement of the mask 130 relative to the first plate 110 in the first direction 141.

[0047] As indicated in FIG. 5, according to some embodiments which can be combined with other embodiments, further chambers can be provided adjacent to the processing chamber 210, e.g. a vacuum processing chamber. For example, the processing chamber 210 can be separated from adjacent chambers by a valve having a valve housing 204 and a valve unit 206. After the mask arrangement 100 is inserted into the processing chamber 210 (exemplarily indicated by arrow 1 in FIG. 5), the valve unit 206 can be closed. The atmosphere in the processing chamber 210 can be controlled by generating a technical vacuum, for example with vacuum pumps connected to the processing chamber, and/or by inserting process gases in a deposition region in the processing chamber. Although not explicitly shown in FIG. 5, it is to be understood that according to embodiments which can be combined with other embodiments described herein, two or more mask arrangements as described herein may be employed during deposition, e.g. in an inline deposition process. For example, two or more carriers including the mask arrangement as described herein may be employed to provide a continuous substrate transport or a continues substrate flow in front of the deposition sources, e.g. sputter deposition sources. In other words, according to some embodiments which can be combined with other embodiments described herein, the apparatus for depositing a layer on a substrate may be configured to provide a continuous carrier train, i.e. two or more carriers following each other (e.g. with or without a gap in between two subsequent carriers). [0048] According to some embodiments, process gases can include inert gases such as argon and/or reactive gases such as oxygen, nitrogen, hydrogen and ammonia (NH3), Ozone (03), activated gases or the like. Within the processing chamber 210, rollers can be provided in order to transport the mask arrangement 100 into and out of the processing chamber 210. For example, the rollers can be arranged for supporting the bottom of the substrate carrier, particularly the mask arrangement as described herein. In some embodiments, one or more heater(s) 211 for the substrate and the substrate carrier, e.g. the mask arrangement as described herein, may be provided, for instance behind the mask arrangement as exemplarily shown in FIG. 5. According to some embodiments, the one or more heater(s) 211 may be set to 600°C or above. For instance, the one or more heater(s) 211 may be one or more resistance heater(s).

[0049] According to embodiments described herein, the mask arrangement 100 may be arranged within the processing chamber 210 such that the mask 130 of the mask arrangement 100 faces the deposition source 220, e.g. the first sputter deposition source 230a and second sputter deposition source 230b. For example, the sputter deposition process can be an RF frequency (RF) sputter deposition process. As an example, the RF sputter deposition process can be used when the material to be deposited on the substrate is a dielectric material. Frequencies used for RF sputter processes can be about 13.56 MHz or higher. According to some embodiments, the (sputter) deposition process may be a middle frequency (MF) deposition process. Frequencies used for MF deposition processes can be between about 20 kHz and about 100 kHz.

[0050] As exemplarily shown in FIG. 5, according to some embodiments which can be combined with other embodiments described herein, the apparatus 200 can have an AC power supply 240 connected to the one or more sputter deposition sources. As an example, the first sputter deposition source 230a and the second sputter deposition source 230b can be connected to the AC power supply 240 such that the first sputter deposition source 230a and the second sputter deposition source 230b can be biased in an alternating manner. The one or more sputter deposition sources can be connected to the same AC power supply. In other embodiments, each sputter deposition source can have an own AC power supply. [0051] According to embodiments described herein, the sputter deposition process can be conducted as magnetron sputtering. As used herein, "magnetron sputtering" refers to sputtering performed using a magnet assembly, e.g., a unit capable of generating a magnetic field. Such a magnet assembly can consist of a permanent magnet. This permanent magnet can be arranged within a rotatable target or coupled to a planar target in a manner such that the free electrons are trapped within the generated magnetic field generated below the rotatable target surface. Such a magnet assembly can also be arranged coupled to a planar cathode. Magnetron sputtering can be realized by a double magnetron cathode, e.g. the first sputter deposition source 230a and the second sputter deposition source 230b, such as, but not limited to, a TwinMag™ cathode assembly. For example, the TwinMag™ cathode may be run by a MF power supply.

[0052] According to some embodiments, which can be combined with other embodiments described herein, the apparatus 200 can be configured to deposit lithium or a lithium alloy on the at least one substrate. In some implementations, the apparatus 200 can be configured to deposit at least one of a metal oxide, such as A1203 or Si02, and a target material. The target material can include one or more element(s) selected from the group consisting of lithium, tantalum, molybdenum, niobium, titanium, manganese, nickel, cobalt, indium, gallium, zinc, tin, silver, copper, and any combination thereof. In particular, the apparatus can be configured to deposit lithium phosphorus oxynitride (LiPON) on the at least one substrate. LiPON is an amorphous glassy material used as an electrolyte material in thin film batteries. Layers of LiPON can be deposited over a cathode material of a thin film battery by RF magnetron sputtering forming a solid electrolyte. [0053] The mask arrangement and the apparatus utilizing the mask arrangement described herein can be used for vertical substrate processing. According to some implementations, the mask arrangement of the present disclosure is configured for holding the at least one substrate in a substantially vertical orientation. The term "vertical substrate processing" is understood to distinguish over "horizontal substrate processing". For instance, vertical substrate processing relates to a substantially vertical orientation of the carrier and the substrate during substrate processing, wherein a deviation of a few degrees, e.g. up to 10° or even up to 15°, from an exact vertical orientation is still considered as vertical substrate processing. The vertical direction can be substantially parallel to the force of gravity. As an example, the apparatus for sputter deposition on at least one substrate can be configured for sputter deposition on a vertically oriented substrate. [0054] It is to be understood that according to embodiments which can be combined with other embodiments described, the mask arrangement may be static or dynamic during sputtering of the deposition material. According to some embodiments described herein, a dynamic sputter deposition process can be provided, e.g., for thin film battery manufacturing. [0055] According to some embodiments of the present disclosure, the sputter deposition sources can be rotatable sputter deposition sources or rotatable cathodes. The sputter deposition sources can be rotatable around a rotational axis. As an example, the rotational axis can be a vertical rotational axis. However, the present disclosure is not limited to rotatable sputter deposition sources or rotatable cathodes. According to some embodiments, which can be combined with other embodiments described herein, the sputter deposition sources can be planar sputter deposition sources or planar cathodes.

[0056] FIG. 6 shows a block diagram illustrating a method 300 for aligning a mask to a substrate according to embodiments described herein. According to embodiments which can be combined with other embodiments described herein, the method includes arranging 310 the substrate 10 on a first surface 101 of a first plate 110 such that the substrate is in contact with a first pin 111 and a second pin 112 protruding from the first surface 101. The first pin 111 is arranged to delimitate a movement of the substrate in a first direction 141 and the second pin 112 is arranged to delimitate a movement of the substrate in a second direction 142, wherein the second direction 142 is different from the first direction 141. Further, the method includes mounting 320 the mask 130 on top of the substrate 10 such that the first pin 111 is received within a first hole 131 of the mask and the second pin 112 is received within a second hole 132 of the mask 130. The first hole 131 is configured for allowing a movement of the mask relative to the first plate 110 in the second direction 142 and the second hole 132 is configured for allowing a movement of the mask 130 relative to the first plate 110 in the first direction 141. Additionally, the method includes holding 330 the substrate 10 and the mask 130 in between the first plate 110 and a second plate 120.

[0057] With exemplary reference to FIG. 7, according to some embodiments of the method 300 for aligning a mask to a substrate which can be combined with other embodiments described herein, holding 330 the substrate 10 and the mask 130 in between the first plate 110 and the second plate 120 may include providing 340 a clamping force on the first plate 110 and a second plate 120. In particular, holding 330 the substrate 10 and the mask 130 in between the first plate 110 and the second plate 120 may include employing 350 a spring element 160 for applying a contact pressure to a central portion of the mask 130.

[0058] In view of the above, it is to be understood that embodiments as described herein provide for effectively holding thin or ultra-thin substrates which may be masked for processing, e.g. layer deposition or coating. Further, embodiments as described herein provide for equalizing any difference in thermal expansion between a mask and a base plate supporting the substrate, such that the substrate and the mask remain properly aligned to each other throughout processing the substrate in which the processing temperature may vary.