FIELD

[001] The present disclosure relates to an apparatus and method for the treatment of flexible substrates. In particular, the present disclosure relates to an apparatus and method for the treatment of flexible substrates using an electron beam.

BACKGROUND

[002] Electron sources are known from a plurality of fields. For example, electron beams are used for material modification, charging of surfaces, imaging of samples, and the like.

[003] Modern manufacturing processes for processing large area substrates or webs, such as, for manufacturing of large area foils, thin-film solar cells, and the like have a tendency towards increasing the overall processing speeds in order to decrease the cost of ownership. Further, in order to maximize the throughput of a manufacturing apparatus, the energy density provided by a source onto a substrate, foil, sheet or web that may be needed for certain processes may also be increased.

[004] Generally, different types of charged particle sources, e.g. electron sources, can be provided. The cathode of the e-gun is heated in order to increase the electron current. The electron work of emission depends on temperature. For an e-gun, a cathode made of a material with low electron affinity is beneficial. The electron emission is caused by high temperature of the cathode and the electric field strength. E-guns often have a (grounded) housing but the housing is not important for operation of the e-gun. E-guns typically do not need a working gas for operation. The gas pressure inside the e-gun is of minor relevance.

[005] For e-charge electron sources, the electrons are generated by ignition and maintaining a plasma inside the housing of the electron source. Electrons are extracted and accelerated towards an elongated slit by an electric field. Ions from the plasma may erode the cathode surface by sputtering and, thus, it is beneficial to have a cathode material with low sputter rate in order to get a long lifetime. The electron affinity of the cathode material is of less relevance.

[006] Typically, during manufacturing processes that employ electron sources, increasing the energy density provided by the source may increase the cost of ownership due to the increased energy consumption of the electron source. Further, substrates of different sizes may need a plurality of different sized electron sources, which may be arranged in separate manufacturing chambers, i.e. each manufacturing chamber may be adapted for a particularly dimensioned substrate.

[007] Accordingly, there is an ongoing need for improved apparatuses and methods for the treatment of flexible substrates using an electron source with an increased efficiency and reduced total cost of ownership.

SUMMARY

[008] In view of the above, according to an aspect, a charged particle device for treatment of a substrate is provided. The charged particle device includes a first device module having: a housing providing a first electrode, the housing having a back wall and a front wall; a slit opening in the housing for enabling a beam of charged particles passing from the inside of the housing to the outside of the housing, the slit opening defining a length direction of the charged particle device; and a second electrode being arranged within the housing and having a first side facing the first slit opening. The second electrode includes: one or more beam shaping extensions that protrude from the first side of the second electrode in a direction towards the front wall of the housing for guiding the charged particle beam through the slit opening.

[009] Further, a charged particle system is provided for the treatment of a substrate. The system includes: a charged particle device including a first device module as described above, wherein the first device module further includes at least one connection element selected from the group consisting of: a connection element for electrical power, a connection element for a gas, and a connection element for a cooling fluid; and a second device module, wherein the second device module includes: a further housing acting as a further portion of the first electrode, the further housing having a further back wall and a further front wall; a further slit opening in the further housing for enabling the beam of charged particles passing from the inside of the further housing to the outside of the further housing; and a further portion of the second electrode being arranged within the further housing and having a further first side facing the further slit opening. The at least one connection element of the first device module is connected to a corresponding connection element of the second device module and wherein the further portion of the second electrode includes a further portion of the one or more beam shaping extensions that protrude from the further first side of the further portion of the second electrode in a direction towards the further front wall of the further housing.

[0010] Furthermore, a method is provided for increasing the extraction efficiency of a charged particle device. The method includes: providing a charged particle device having: a housing providing a first electrode, the housing having a back wall and a front wall; a second electrode being arranged within the housing; a slit opening in the housing, and one or more beam shaping extensions that protrude from the second electrode in a direction towards the front wall of the housing; igniting a plasma for producing charged particles from the second electrode of the charged particle device; and guiding a beam of charged particles via the one or more beam shaping extensions through the slit opening of the charged particle device.

[0011] Further aspects, advantages and features of the present disclosure are apparent from the dependent claims, the description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Some of the above mentioned embodiments will be described in more detail in the following description of embodiments with reference to the following drawings in which:

[0013] Fig. 1 shows a schematic view of a charged particle device according to embodiments described herein;

[0014] Fig. 2 shows a schematic view of a charged particle device according to further embodiments described herein;

[0015] Fig. 3 shows a yet further schematic view of the charged particle device shown in Fig. laccording to embodiments described herein;

[0016] Fig. 4 shows a schematic view of a system for the treatment of a substrate according to embodiments described herein;

[0017] Fig. 5 shows a perspective view of a charged particle system according to embodiments described herein;

[0018] Fig. 6 shows a perspective view of a charged particle device according to embodiments described herein;

[0019] Fig. 7 shows a further perspective view of a charged particle device according to embodiments described herein;

[0020] Fig. 8 shows schematically a method for increasing the extraction efficiency of a charged particle device according to embodiments described herein.

DETAILED DESCRIPTION

[0021] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. Within the following description of the drawings, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet further embodiments. It is intended that the present disclosure includes such modifications and variations.

[0022] Embodiments described herein relate to charged particle devices, in particular linear electron devices and methods for increasing the extraction efficiency of a charged particle device, which can be used for a plurality of applications. According to embodiments herein, the yield of charged particles from a linear charged particle device may be increased in order to improve modern manufacturing methods of substrates including films, sheets, foils, webs and the like.

[0023] The charged particle devices and methods described herein are not limited to the use of flexible substrates but may be equally well be utilized for the treatment of rigid substrates. The term "substrate" as used herein shall refer to both inflexible substrates, e.g., a wafer or a glass plate, and flexible substrates, such as, webs and foils. The terms "charged particle beam", "beam of charged particles" and "beam" are used interchangeably herein.

[0024] According to embodiments herein, a charged particle device is provided for the treatment of substrates, in particular, for the treatment of moveable substrates. The charged particle device may include a source for forming a beam of charged particles for the treatment of the substrate moving along a transport direction. For example, the charged particle device may form a linear beam of charged particles such as electrons. According to embodiments herein, the charged particle device may be used in polymerization reactions that may, for example, form polymer films on flexible substrates. According to embodiments described herein, the charged particle source can be an e-charge electron source.

[0025] Further, according to embodiments herein, the charged particle device may be adapted to increase the extraction efficiency of charged particles from the charged particles source that are projected as beam of charged particles towards the substrate. Increasing the extraction efficiency may include minimizing secondary emission and increasing the energy transmission efficiency from the charged particle device to the substrate to be treated.

[0026] Furthermore, according to embodiments herein, a charged particle system for treatment of a substrate may be adapted to include a charged particle device, which can be operated including one, two or more charged particle device modules that can be connected to one another. Such a modular system may facilitate the treatment of substrates with different dimensions. For instance, one charged particle device module may be utilized for treating narrow substrates and two, three or more charged particle device modules connected to one another may be employed for treating wider substrates. According to embodiments herein, a single charged particle system may be adapted for treating both narrow and wide substrates.

[0027] According to embodiments described herein, a method for increasing the extraction efficiency of a charged particle device is provided. The method may increase the density of charged particles transmitted from a charged particle device to a substrate to be treated. For instance, an increased density of charged particles in the charged particle beam from the charged particle device may allow for an increased distance between the charged particle device and the substrate to be treated. According to embodiments herein, the method includes guiding a beam of charged particles from a charged particle device via a beam shaping extension, in particular, guiding the beam of charged particles via the electric field lines formed between the beam shaping extension and the anode of the charged particle device, towards the substrate to be treated.

[0028] Fig. 1 shows a section of a charged particle device 100 for treatment of a substrate in a cross-section along a direction, which is perpendicular to a longitudinal axis of the charged particle device. The longitudinal axis of the charged particle device may be defined as the direction into and out of the page.

[0029] According to embodiments herein, the charged particle device 100 may include a housing 110. The housing 110 may provide a first electrode. According to embodiments herein, the first electrode may be the anode, which may optionally be grounded. The housing 110 may have a back wall 112 and a front wall 114. The front wall 114 and the back wall 112 of the housing 110 may be connected to each other via a first side wall 111 and a second side wall 113. According to embodiments herein, the first side wall 111 and the second side wall 113 may be arranged parallel to each other.

[0030] In embodiments described herein, the front wall 114 of the housing 110 includes an extraction aperture, which may hereinafter be referred to as slit opening 116. The slit opening 116 may be adapted for enabling a beam of charged particles passing from the inside of the housing to the outside of the housing. According to embodiments herein, the slit opening 116 may divide the front wall 114 of the housing 110 into a first front wall portion 115 and a second front wall portion 117. The first front wall portion 115 and the second front wall portion 117 may be symmetric with respect to the line of symmetry 101 defined as a plane dividing the charged particle device 100 into equal halves. For instance, the line of symmetry 101 may be perpendicular to the back wall 112 of the housing 110 of the charged particle device 100. The slit opening 116 may define a length direction of the charged particle device 100. In the exemplary embodiment shown in Fig. 1, the length direction of the charged particle device 100 may be described as being into or out of the page.

[0031] According to embodiments herein, the front wall 114 of the housing 110 including the first front wall portion 115 and/or the second front wall portion 117 may be configured to be arranged towards a second electrode 120. For instance, the first front wall portion 115 and/or the second front wall portion 117 may be inclined towards the second electrode 120, particularly with an inclination having a first end of the front wall portion adjacent to the slit opening closer to the cathode as compared to an opposing end of the respective front wall portion. Generally, according to embodiments herein, during operation of the charged particle device 100, plasma may be formed within the housing 110, in the space 102 between the second electrode 120 and the front wall 114 of the housing 110. Further, according to embodiments herein, end walls (not shown in the figures) may cover either end of the housing of the charged particle device 100. Furthermore, according to embodiments described herein, the charged particle device 100 may include at least one connection element selected from the group consisting of: a connection element for electrical power, a connection element for a gas, and a connection element for a cooling fluid.

[0032] In embodiments described herein, the second electrode 120 may be arranged within the housing 110. The second electrode may be the cathode and may include materials with low sputter rate but high secondary electron co-efficient such as, for example, graphite and carbon fibre composites (CFC). In embodiments herein, the second electrode may extend in a direction parallel to the length direction of the charged particle device 100.

[0033] According to embodiments herein, the second electrode 120 has at least a first side 122 facing the slit opening 116 of the housing 110 (i.e. the first side of the second electrode may also be referred to as a front side of the second electrode). In some embodiments described herein, the first side 122 may be curved. The curvature of the first side 122 may increase the extraction efficiency of the charged particle device 100. For example, the first side 122 may be curved away from the slit opening 116 and be referred to as a concave first side, which may increase the surface area of the second electrode 120 and which may help to focus the beam of charged particles emitted from the second electrode towards the slit opening 116. The second electrode 120 may also have a second side 124 facing the back wall 112 of the housing 110 (i.e. the second side of the second electrode may also be referred to as a rear side of the second electrode).

[0034] According to embodiments herein, the second electrode 120 has one or more beam shaping extensions 125, 129. The one or more beam shaping extensions 125, 129 protrude from the second electrode 120 in a direction towards the front wall 114 of the housing 110. Accordingly, the second electrode including the beam shaping protrusions may have a U- shape or C- shape form. Generally, the one or more beam shaping extensions may extend in a direction parallel to the longitudinal direction of the second electrode 120. Not limited to any one particular embodiment described herein, the second electrode may include a single beam shaping extension, two beam shaping extensions or a plurality of beam shaping extensions.

[0035] According to embodiments herein, the one or more beam shaping extensions 125, 129 may be configured to guide a charged particle beam emanating from the second electrode 120 through the slit opening 116 in order to further increase the extraction efficiency of the charged particle device 100. In particular, the one or more beam shaping extensions may be adapted such that during operation, electric field lines formed between the one or more beam shaping extensions 125, 129 and the housing 110 of the charged particle device 100 guide electrons, which are generated by the interaction of ions from the plasma with the second electrode 120, towards the slit opening 116. An exemplary trajectory of the beam of charged particles including the Coulomb repulsion of electrons by space charge is illustrated in Fig. 1 (see reference number 105).

[0036] In embodiments described herein, the second electrode 120 of the charged particle device 100 may include a first beam shaping extension 125 and a second beam shaping extension 129. The first beam shaping extension 125 and the second beam shaping extension 129 may be arranged on opposite ends of the second electrode 120. According to embodiments herein, the first beam shaping extension and/or the second beam shaping extension may be integrally formed with the second electrode. In yet further embodiments described herein, the first beam shaping extension and/or the second beam shaping extension may be manufactured separately and connected to the second electrode during assembly of the second electrode.

[0037] According to embodiments herein, the one or more beam shaping extensions 125, 129 may have at least a first side 128, 132, which may be arranged to be adjacent to the first side 122 of the second electrode 120. In embodiments described herein, the first side 128, 132 of the one or more beam shaping extensions 125, 129 may be curved. According to embodiments described herein, the one or more beam shaping extensions 125, 129 may each have a second side 126, 130. The second sides 126, 130 of the one or more beam shaping extensions 125, 129 may be configured to face the side wall 111 and the second side wall 113 of the housing 110 respectively. In embodiments described herein, the second sides 126, 130 of the one or more beam shaping extensions 125, 129 may be arranged to be parallel with respect to at least one of the first side wall 111 and second side wall 113 of the housing 110.

[0038] Further, according to embodiments herein, the one or more beam shaping extensions 125, 129 may have a front side 127, 131 that faces the front wall 114 of the housing 110. For instance, the front side 127 of the first beam shaping extension 125 may face in a direction towards the first front wall portion 115 of the housing 110. The front side 131 of the second beam shaping extension 129 may face in a direction towards the second front wall portion 117 of the housing 110. In embodiments described herein, the edge that may be formed between the one or more front sides 127, 131 and the one or more second sides 126, 130 may support the ignition of plasma during operation of the charged particle device 100. Further, the orientation of the one or more front sides 127, 131 may be parallel to the second side 124 of the second electrode 120.

[0039] Generally, the one or more beam shaping extensions 125, 129 of the second electrode 120 may be arranged to be spaced away from the first side wall 111 and the second side wall 113 of the housing 110 respectively. A dark space may be formed in the space between the one or more second sides 126, 130 of the one or more beam shaping extensions 125, 129 and the first side wall 111 and/or second side wall 113 of the housing 110, respectively. In embodiments herein, the second electrode 120 may also be spaced away from the back wall 112 of the housing 110 such that a dark space is formed in the space between the second side 124 of the second electrode 120 and the back wall 112 of the housing 110.

[0040] According to embodiments herein, the dark space may prevent plasma generation, which may increase the energy efficiency of the charged particle device 100 due to reducing the formation of plasma in unwanted spaces within the housing 110 of the charged particle device 100. A further advantageous effect of the dark space, which contributes to the overall improved energy efficiency of the charged particle device 100, may be to prevent energy loss due to excessive heating of the housing 110.

[0041] According to embodiments herein, the charged particle device 100 may include a cooling system for cooling the housing 110, which may further improve the energy efficiency of the charged particle device 100. For instance, a cooling system 150 that includes at least one passageway to accommodate a cooling fluid may be arranged to cool the back wall 112 of the housing 110. According to embodiments herein, the cooling system may be formed integrally with the housing 110. According to further embodiments herein, the cooling system may, for instance, be formed at least partially within the back wall 112 of the housing 110.

[0042] Not limited to any particular embodiment described herein, the cooling system may further be configured to cool at least one of the first side wall 111, second side wall 113 and front wall 114 of the housing 110 (including the first front wall portion 115 and/or the second front wall portion 117). For the purpose of cooling at least one of the first side wall 111, the second side wall 113, the first front wall portion 115 and the second front wall portion 117 of the housing 110, one or more passageways for accommodating a cooling fluid may be provided in each of the first side wall 111, the second side wall 113, the first front wall portion 115 and the second front wall portion 117 of the first housing 110 portion respectively.

[0043] Fig. 2 shows a section of a charged particle device 200 for treatment of a substrate in a cross-section along a direction which is perpendicular to a longitudinal axis of the charged particle device. The longitudinal axis of the charged particle device may be defined as the direction into and out of the page.

[0044] According to embodiments herein, the charged particle device 200 has a similar set up to the charged particle device 100 shown in Fig. 1. For example, the charged particle device 200 includes a housing 210, which may provide a first electrode. According to embodiments herein, the first electrode may be the anode, which may optionally be grounded. The housing 210 may have a back wall 212 and a front wall 214. The front wall 214 and the back wall 212 of the housing 210 may be connected to each other via a first side wall 211 and a second side wall 213. According to embodiments herein, the first side wall 211 and the second side wall 213 may be parallel to each other.

[0045] In embodiments described herein, the front wall 214 of the housing 210 may include an extraction aperture, which may hereinafter be referred to as opening portion or slit opening 216. The slit opening 216 may be adapted for enabling a beam of charged particles passing from the inside of the housing to the outside of the housing. According to embodiments herein, the slit opening 216 may divide the front wall 214 of the housing 210 into a first front wall portion 215 and a second front wall portion 217. The first front wall portion 215 and the second front wall portion 217 may be symmetric with respect to the line of symmetry 201 defined as a plane dividing the charged particle device 200 into equal halves. For instance, the line of symmetry 201 may be perpendicular to the back wall 212 of the housing 210 of the charged particle device 200. The slit opening 216 may define a length direction of the charged particle device 200. In the exemplary embodiment shown in Fig. 2, the length direction of the charged particle device 200 may be described as being into or out of the page.

[0046] According to embodiments herein, the front wall 214 of the housing 210 including the first front wall portion 215 and/or the second front wall portion 217 may be configured to be arranged towards a second electrode 220. For instance, the first front wall portion 215 and/or the second front wall portion 217 may be inclined towards the second electrode 220. Generally, according to embodiments herein, during operation of the charged particle device 200, plasma may be formed in the space 202 within the housing 210.

[0047] In embodiments described herein, the second electrode 220 may be arranged within the housing 210. The second electrode may be the cathode and may include materials with low sputter rate but high secondary electron co-efficient. According to different embodiments, the anode can, for example, be manufactured from a material like copper, aluminium, steel, mixtures thereof, and the like. According to different embodiments, which can be combined with other embodiments described herein, the cathode can include a material selected from the group consisting of: steel, stainless steel, copper, aluminium, graphite, CFC (carbon-fibre-reinforced carbon), composites thereof, or mixtures thereof. In embodiments herein, the second electrode may extend in a direction parallel to the length direction of the charged particle device 200.

[0048] Similar to the embodiment shown in Fig. 1, the charged particle device 200 may include a cooling system for cooling the housing 210. For instance, a cooling system 250 that includes at least one passageway to accommodate a cooling fluid may be arranged to cool the back wall 212 of the housing 210. According to embodiments herein, the cooling system may be formed integrally with the housing 210. According to further embodiments herein, the cooling system may, for instance, be formed at least partially within the back wall 212 of the housing 210.

[0049] The second electrode 220 has at least a first side 222 facing the slit opening 216 of the housing 210. In embodiments described herein, the first side 222 may be curved. The curvature of the first side 222 may increase the extraction efficiency of the charged particle device 200. For example, the first side 222 may be curved away from the slit opening 216 and be referred to as a concave first side. The second electrode 220 may also have a second side 224 facing the back wall 212 of the housing 210.

[0050] According to embodiments herein, the second electrode 220 has one or more beam shaping extensions 225, 229. The one or more beam shaping extensions 225, 229 protrude from the second electrode 220 in a direction towards the front wall 214 of the housing 210. Generally, the one or more beam shaping extensions may extend in a direction parallel to the longitudinal direction of the second electrode 220.

[0051] Similarly to the one or more beam shaping extensions described with respect to Fig. 1, the one or more beam shaping extensions of the embodiment shown in Fig. 2 may be configured to guide a charged particle beam emanating from the second electrode 220 through the slit opening 216 in order to increase the extraction efficiency of the charged particle device 200. In particular, the one or more beam shaping extensions may be adapted such that during operation, electric field lines formed between the one or more beam shaping extensions 225, 229 and the housing 210 of the charged particle device 200, guide electrons that are generated by the interaction of ions from the plasma with the second electrode 220, towards the slit opening 216. An exemplary trajectory of the beam of charged particles including the Coulomb repulsion of electrons by space charge is illustrated in Fig. 2 (see reference number 205).

[0052] In embodiments described herein, the second electrode 220 of the charged particle device 200 may include a first beam shaping extension 225 and a second beam shaping extension 229. The first beam shaping extension 225 and the second beam shaping extension 229 may be arranged on opposite ends of the second electrode 220. According to embodiments herein, at least one of the first beam shaping extension 225 and the second beam shaping extension 229 may be integrally formed with the second electrode 220. In yet further embodiments described herein, at least one of the first beam shaping extension 225 and the second beam shaping extension 229 may be manufactured separately and connected to the second electrode 220 during assembly of the second electrode 220.

[0053] According to embodiments herein, the one or more beam shaping extensions 225, 229 may have at least a first side 228, 232, which may be arranged to be adjacent to the first side 222 of the second electrode 220. In embodiments described herein, the first side 228, 232 of the one or more beam shaping extensions 225, 229 may be curved. According to embodiments described herein, the one or more beam shaping extensions 225, 229 may each have a second side 226, 230. The second sides 226, 230 of the one or more beam shaping extensions 225, 229 may be configured to face a first side wall 211 and a second side wall 213 of the housing 210 respectively. In embodiments described herein, the second sides 226, 230 of the one or more beam shaping extensions 225, 229 may be arranged to be parallel with respect to at least one of the first side wall 211 and second side wall 213 of the housing 210 or within an angle of + 20°.

[0054] In embodiments described herein, the first side 228 of the first beam shaping extension 225 may be inclined, for instance, with respect to at least one of the first side wall 211 and second side wall 213 of the housing 210. For example, the acute angle (α') formed between a straight line extending parallel to the first side 228 of the first beam shaping extension 225 and a straight line extending parallel to the first side wall 211 of the housing 210 may be from 5° to 85°, for instance, 35°, 45° or 55°. Alternatively, the inclination of the first side 228 of the first beam shaping extension 225 may be defined with respect to a longitudinal axis of the beam of charged particles 207. For instance, the acute angle (a") formed between a straight line extending parallel to the first side 228 of the first beam shaping extension 225 and the longitudinal axis of the beam of charged particles 207 may be from 5° to 85°, for instance, 35°, 45° or 55°. According to embodiments herein, similarly the first side 232 of the second beam shaping extension 229 may be inclined, for instance, with respect to at least one of the first side wall 211 and second side wall 213 of the housing 210. For example, the acute angle (α"') formed between a straight line extending parallel to the first side 232 of the second beam shaping extension 229 and a straight line extending parallel to the second side wall 213 of the housing 210 may be from 5° to 85°, for instance, 35°, 45° or 55°. Alternatively, the inclination of the first side 232 of the first second beam shaping extension 229 may be defined with respect to a longitudinal axis of the beam of charged particles 207. For instance, the acute angle (a"") formed between a straight line extending parallel to the first side 232 of the second beam shaping extension 229 and the longitudinal axis of the beam of charged particles 207 may be from 5° to 85°, for instance, 35°, 45° or 55°.

[0055] Further, in embodiments herein the first side 228 and the second side 226 of the first beam shaping extension 225 may be adjacent to each other. The first side 228 and the second side 226 may form an edge at the point where they meet. Similarly, the first side 232 and the second side 230 of the second beam shaping extension 229 may be adjacent to each other. The first side 232 and the second side 230 may also form an edge at the point where they meet. The small radius of curvature of the edge formed between the first side 228 and the second side 226 of the first beam shaping extension 225, and the edge formed between the first side 232 and the second side 230 of the second beam shaping extension 229 may support the ignition of plasma during operation of the charged particle device 200.

[0056] Generally, the one or more beam shaping extensions 225, 229 of the second electrode 220 may be arranged to be spaced away from the first side wall 211 and the second side wall 213 of the housing 210. A dark space may be formed in the space between the one or more second sides 226, 230 of the one or more beam shaping extensions 225, 229 and the first side wall 211 and/or second side wall 213 of the housing 210, respectively. In embodiments herein, the second electrode 220 may also be spaced away from the back wall 212 of the housing 210 such that a dark space is formed in the space between the second side 224 and the back wall 212 of the housing 210.

[0057] To even better describe the charged particle device according to embodiments described herein, Fig. 3 shows the same section of the charged particle device 100 as illustrated in Fig. 1. In general, Fig. 3 refers to the embodiment shown in Fig. 1. However, the dimensions of the features and their relationship with each other also apply to other embodiments described herein, in particular, for instance, with respect to the embodiment shown in Fig. 2. Further, the geometry of the charged particle devices shown in the figures, particularly the cross-sectional views shown e.g. in Fig. 1 and Fig. 2 depict examples of the charged particle device according to embodiments herein. The specific geometry shown in the figures is not intended to limit the scope of the present disclosure in any way. Further adaptations of the charged particle device with different geometries are within the scope of the present disclosure.

[0058] In general, the charged particle device 100 may have a width 304 greater than 30 mm, for instance, anywhere from 30 to 80 mm, such as, for example, 50 mm. The charged particle device 100 may have a height 301 greater than 70 mm, for instance, anywhere from 70 mm to 130 mm, such as, for example, 100 mm. Further, the second electrode 120 may have a height 302 greater than 30 mm, for instance, anywhere from 30 mm to 50 mm, such as, for example, 40 mm. Furthermore, the height 303 or size of the slit opening 116 may be greater than 2 mm, for instance, anywhere from 2 mm to 10 mm, such as, for example, 6 mm.

[0059] Fig. 3 further shows a parallel projection 309' of the charged particle device 100 on a projection plane 310. The projection plane may function as a coordinate system in one-dimensional space. The width of the back wall 112 of the housing 110 may, for example, be defined as the length 311 along the projection plane 310. According to embodiments herein, the length 311 may be greater than 3 mm, for instance, anywhere from 3 mm to 30 mm, such as, for instance, 10 mm. Generally, according to embodiments herein, a dark space separates the back wall 112 of the housing 110 from the second electrode 120. The dark space may have a width defined by the length 312 along the projection plane. The length 312 may be greater than 2 mm, for instance, anywhere from 2 mm to 10 mm, such as, for example, 5 mm. The second electrode 120 may have a width defined by the length 313 along the projection plane. The length 313 may be greater than 5 mm, for instance, anywhere from 5 mm to 30 mm, such as, for example, 10 mm. The one or more beam shaping extensions 125, 129 may protrude from the second electrode 120 in a direction towards the front wall, in particular, towards the first front wall portion 115 and/or second front wall portion 117 of the housing 110 by a length 314. The length 314 may be greater than 2 mm, for instance, anywhere from 2 mm to 20 mm, such as, for instance, 5 mm. Not limited to any particular embodiment herein, each of the beam shaping extensions may protrude from the second electrode in a direction towards the front wall of the housing by a different length 314.

[0060] Further according to embodiments herein, the shortest distance between the first beam shaping extension 125 and/or the second beam shaping extension 129 with respect to the front wall portion of the housing 110 may be defined by length 315. According to embodiments herein, length 315 may be greater than 10 mm, for instance, anywhere from 10 mm to 60 mm, such as, for instance, 30 mm. In the embodiments described herein, the length 316 along the projection plane 309 between the furthest and closest point of the front wall of the housing 110 with respect to the one or more beam shaping extensions 125, 129 may be greater than 0 mm, for instance, anywhere from 0 mm to 30 mm, such as, for instance, 15 mm.

[0061] Fig. 4 shows a schematic view of a system for the treatment of a substrate according to embodiments described herein. The system 400 includes a charged particle device 100 having a cathode, and an anode provided by the housing 110 having a slit opening 116 provided in the front face of the charged particle device 100. In particular, according to embodiments herein, the system 400 for treating a substrate may include any of the previously described charged particle devices 100, 200 (e.g. see Fig. 1, Fig. 2 and Fig. 3) and is not limited to any specific charged particle device or charged particle system described herein.

[0062] A high voltage can be provided to the cathode by the electrical connection 410, which may pass through an isolating cathode support member 422. According to yet further embodiments, the isolating cathode support member 422 may also be provided in a gas sealing manner such that the pressure difference from the interior of the housing 110 and the exterior of the housing 110 can be maintained. The housing may be grounded to provide the anode on a ground potential. The voltage between the cathode and the anode may result in the generation of plasma in the space 102 within the housing 110. Charged particles such as electrons generated in the plasma may be accelerated towards the anode. Electrons being accelerated towards the front portion of the cathode may exit the charged particle device 100 through the opening 116 as a beam of electrons.

[0063] According to embodiments herein, in addition to one or more isolating cathode support members, the cathode may be connected to the back wall of the housing of the charged particle device by one or more electrically insulating cathode support elements, for example, two, three, four or more electrically insulating cathode support elements. According to embodiments, herein the one or more electrically insulating cathode support elements may support the cathode and ensure an equal spacing, in a direction parallel to the length direction of the charged particle device, between the cathode and the back wall of the housing. This ensures that a predetermined dark space is provided between the cathode and the back wall of the housing. In embodiments herein, the one or more electrically insulating cathode support elements may, for instance, be guided via holes through the back wall of the housing. The one or more electrically insulating cathode support elements may be arranged movable (e.g. spring-loaded) in order to allow for a thermal expansion of the cathode, in particular, in order to allow for a linear thermal expansion of the cathode in a direction parallel to the length direction of the charged particle device.

[0064] According to some embodiments, the power supply for providing a voltage to the cathode (second electrode 120) may be adapted for controllably providing a voltage in a range of for example from -5 kV to -30 kV, typically in a range from -5 kV to -14 kV. The cathode may be mounted within the housing 110 and may be spaced away from the housing 110. Typically, the cathode may be spaced away from the housing 110 at a distance that is sufficiently large to reduce or prevent arcing and can for example be in a range of 2 to 12 mm, typically 3 to 8 mm, for example, 4 to 5 mm. According to embodiments described herein, the separation spaces between the cathode and the housing may be chosen to be sufficiently large to prevent arcing and sufficiently small to reduce or prevent gas discharge between the cathode and the housing in regions where a gas discharge is not intended, for instance, in regions other than the region in front of the cathode, between the cathode and the slit opening 116 of the charged particle device 100. [0065] As briefly described with respect to Fig. 1, according to embodiments herein, the shape of the cathode may include a concave front portion facing the slit opening 116. The concave portion may facilitate to better direct the initial velocity of the charged particles generated in the vicinity of the cathode towards the front of the housing and, in particular, towards the slit opening 116 of the charged particle device 100.

[0066] A gas like noble gases, e.g., argon, N ₂ , 0 ₂ , mixtures thereof or the like may be provided via a gas conduit 430 from a gas tank 470 through one or more valves 472 into the housing 110 for generating plasma. Generally, the pressure within the housing may be anywhere from 10 ^" mbar to 100 mbar. Further, according to some embodiments described herein, one or more of the elements of a gas conduit, a valve, a gas tank, and the like can be used in a gas supply for supplying a gas like noble gases, e.g., argon, N ₂ , 0 ₂ , mixtures thereof or the like into the housing of the charged particle device. According to further embodiments, which can be yielded by combinations with other embodiments, at least two gas supplies or even at least seven gas supplies can be provided. The two or more gas supplies may typically share components like the gas tank, gas conduits from the tank to a gas distributor, and/ or valves.

[0067] The one or more valves 472 may be controlled by controller 490 as indicated by arrow 474. According to some embodiments described herein, which can be combined with other embodiments described herein, the one or more valves 472 can be controlled with a reaction time in a range of 1 to 10 msec. For example, in the case of arcing occurring between the cathode and the anode an advantageously fast reaction can be realized.

[0068] Generally, the current and the electron beam intensity can be controlled by the amount of gas provided in the plasma region. The current provided to the linear electron source may be proportional to the current provided by the emission of electrons. For example, if the current should be reduced, the one or more valves 472 may be controlled such that the amount of gas in the plasma region is decreased.

[0069] The high voltage for a cathode may be provided by the power supply 480. According to some embodiments, the controller 490 measures the current provided from the constant voltage source to the cathode. This is indicated by arrow 495 in Fig. 4. Further, as indicated by arrow 482 the voltage supply may include a detection device such as a sensor. According to embodiments herein, the detection device may, for instance, be an arcing control. If arcing occurs between the cathode and the anode the current might show a rapid increase which can be detected by the arcing rejection means of the power supply 480. According to some embodiments, which can be combined with other embodiments described herein, the voltage supply may be adapted for switching off and on in a millisecond range, for example 1 msec to 10 msec. Generally, the reaction time might dependent on the velocity a substrate being moved along the electron source. Thus, for very fast moving substrates, the reaction time might even be faster or can be lower if the substrate is not moved or only slowly moved. If arcing occurs, the power supply 480 can be immediately switched off and further switched on again immediately after the arcing disappears. On the one hand, this allows for stable operation of the linear electron source. On the other hand, the operation can be quasi-continuous. This is in particular relevant if the linear electron source is used for applications for which a target is a fast moving web, foil and the like.

[0070] According to embodiments herein, a main control unit 492, which may have a display device 491 and an input device 493 like a keyboard, a mouse, a touch screen, or the like, may provide predetermined values for the current and the voltage. The predetermined current, i.e. the electron beam intensity may be provided to the controller 490 as indicated by arrow 494. The controller 490 may, for instance, measure the present current and adjusts the gas flow in the event the present current is not equal to the predetermined current. The main control unit 492 may further give a predetermined value for a voltage to the variable power supply 480 as indicated by arrow 484 in Fig. 4. Similarly, the controller 490 may provide a computed value for the voltage to the variable power supply 480 as indicated by arrow 496. The voltage provided between the cathode and the anode can be used to influence the energy of the emitted electrons. During normal operation of the system 400, the power supply 480 may set the cathode (second electrode 120) on a constant potential in a range of -3 to - 30 kV, typically -5 to -10 kV, for example -10 kV. Since the anode may be grounded, a constant voltage between the cathode and the anode may be applied. [0071] According to embodiments herein, the system 400 shown in Fig. 4 may further include a cooling system having, for instance, a temperature sensor, a heat exchanger and a pump for circulating the cooling fluid (not shown in the figures). A cooling fluid may be provided via a cooling fluid conduit 467 from a cooling fluid tank 460 through one or more valves 462 to the housing 110. Generally, the one or more valves 462 may be controlled by controller 490 as indicated by arrow 464.

[0072] According to embodiments herein, the main control unit 492 may provide predetermined temperature values for the cooling system. The predetermined temperature may be provided to the controller 490 as indicated by arrow 494. The controller 490 may, for instance, measure the present temperature and adjusts the cooling fluid flow rate in the event the present temperature is not equal to the predetermined temperature.

[0073] Fig. 5 shows a perspective view of a charged particle system according to embodiments herein. The charged particle system 500 may be modular, which facilitates handling, assembly and servicing of the charged particle device. For instance, the charged particle system 500 may include a first device module 170 and a second device module 180. In embodiments described herein, the first device module 170 may, for instance, include any one or more features as described with respect to the embodiments shown in any of Fig. 1 and Fig. 2. Similarly, the second device module 180 may also include any one or more features as described with respect to any of the embodiments shown in Fig. land Fig. 2.

[0074] For example, according to embodiments herein, the first device module 170 may include a first housing portion that may provide a first portion of a first electrode. According to embodiments herein, the first electrode may be the anode, which may optionally be grounded. The first housing portion may have a back wall portion and a front wall portion 114. The front wall portion 114 and the back wall 112 portion of the first housing portion may be connected to each other via a first side wall portion and a second side wall 113 portion . According to embodiments herein, the first side wall 111 portion and the second side wall portion may be parallel to each other. [0075] In embodiments described herein, the front wall portion 114 of the first housing portion may include a first slit opening portion. The first slit opening portion may be adapted for enabling a beam of charged particles passing from the inside of the housing to the outside of the housing. According to embodiments herein, the first slit opening 116 portion may divide the front wall portion 114 of the first housing portion into a first front wall portion 115 and a second front wall portion 117.

[0076] According to embodiments described herein, the first device module 170 further includes a first portion of a second electrode arranged within the first housing portion . Due to the perspective view of the first device module 170 shown in Fig. 5, the first portion of the second electrode is not shown. According to embodiments herein, the front wall portion 114 of the first housing portion including the first front wall portion 115 and/or the second front wall portion 117 may be configured to be arranged towards the first portion of the second electrode. For instance, the first front wall portion 115 and/or the second front wall portion 117 may be inclined towards the first portion of the second electrode.

[0077] According to embodiments herein, the first device module 170 of the embodiment shown in Fig. 5 includes any one or more of the features described with respect to the embodiment of the charged particle device 100 shown in Fig. 1. In particular, the first device module 170 may include a first portion of one or more beam shaping extensions and optionally a cooling system as described with respect to the embodiment of the charged particle device 100 shown in Fig. 1.

[0078] According to embodiments herein, the first device module 170 of the embodiment shown in Fig. 5 may further include at least one connection element selected from the group consisting of: a connection element for electrical power 172, a connection element for a gas 174, and a connection element for a cooling fluid 173. The at least one connection element may provide the electrical power, gas and cooling fluid during operation of the charged particle system.

[0079] In embodiments described herein, the charged particle system 500 may further include a second device module 180. The second device module 180 may include a further housing 510 that may provide a further portion the first electrode. According to embodiments herein, the further portion of the first electrode may be the anode, which may optionally be grounded. The further housing 510 may have a further back wall 512 and a further front wall 514. The further front wall 514 and the further back wall 512 of the further housing 510 may be connected to each other via a further first side wall 511 and a further second side wall 513. According to embodiments herein, the further first side wall 511 and the further second side wall 513 may be parallel to each other.

[0080] In embodiments described herein, the further front wall 514 of the further housing 510 may include a further slit opening 516. The further slit opening 516 may be adapted for enabling a beam of charged particles passing from the inside of the further housing to the outside of the further housing. According to embodiments herein, the further slit opening 516 may divide the further front wall 514 of the further housing 510 into a further first front wall portion 515 and a further second front wall portion 517.

[0081] According to embodiments described herein, the second device module 180 may further include a further portion 520 of the second electrode 120 arranged within the further housing 510. According to embodiments herein, the front wall 514 of the further housing 510 including the further first front wall portion 515 and/or the further second front wall portion 517 may be configured to be arranged towards the further portion 520 of the second electrode 120. For instance, the further first front wall portion 515 and/or the further second front wall portion 517 may be inclined towards the further portion 520 of the second electrode 120.

[0082] According to embodiments herein, the second device module 180 of the embodiment shown in Fig. 5 includes any one or more of the features described with respect to the embodiment of the charged particle device 100 shown in Fig. 1. In particular, the second device module 180 may include a further one or more beam shaping extensions 525, 529 and optionally a cooling system (not shown in Fig. 5) as described with respect to the embodiment of the charged particle device 100 shown in Fig. 1. [0083] According to embodiments herein, the second device module 180 of the embodiment shown in Fig. 5 may further include at least one connection element selected from the group consisting of: a connection element for electrical power 182, a connection element for a gas 184, and a connection element for a cooling fluid 183. The at least one connection element may provide the electrical power, gas and cooling fluid during operation of the charged particle system.

[0084] In embodiments described herein, the first device module 170 and the second device module 180 may be configured to be connected releasable to each other. For instance, the first device module and the second device module may be moveably connected to one another via a connection plate 540, that is fixed to the first device module and the second device module by connection means, such as, for example screws.

[0085] According to embodiments described herein, the at least one connection element 172, 173, 174 of the first device module 170 may be connected to a corresponding connection element 182, 183, 184 of the second device module 180. For example, the connection element for the cooling fluid of the first device module may include a connector adapted to create a sealing connection with the corresponding connection element for the cooling fluid of the second device module.

[0086] Further, according to embodiments herein, the connection element for electrical power of the first device module may include a spring-loaded connecting bushing adapted to create an electrical connection with the corresponding connection element for electrical power of the second device module. The spring-loaded connecting bushing may include a tube and a spring. The tube may, for instance, contain graphite and the spring may, for instance, contain temperature-resistant steel. In general, according to embodiments herein, the spring-loaded connecting bushing may be arranged to connect the second electrode and further portion of the second electrode.

[0087] According to embodiments herein, the first device module and the second device module may have a different length in the length direction 550. Generally, according to embodiments herein end plates 171 may be mounted to each end of the charged particle system. Once connected to each other, the first device module and the second device module may form a charged particle system including a continuous slit opening for forming a continuous beam of charged particles, e.g. a continuous and uniform beam of charged particles. The charged particle system may also have at least one of: a continuous housing, a continuous second electrode and continuous one or more beam shaping extensions.

[0088] According to embodiments herein, the modular charged particle system may include more than two device modules, such as for example three, four, five or six device modules arranged in a length direction. Due to the easy and releasable connection between the individual device modules, the charged particle system may easily be adapted for treating substrates of different widths without having to replace the whole system. Not limited to any particular embodiment herein, the embodiments shown with respect to Fig. 1 and Fig. 2 may equally well form a modular charged particle system as described with respect to Fig. 5 above. In particular, each device module may have the components as described with respect to the embodiments shown in Fig. 1 and Fig. 2, respectively.

[0089] Fig. 6 and Fig. 7 show a charged particle device 600 according to embodiments herein. The charged particle device 600 may include a housing 610. The housing 610 may include a back wall 612 and a front wall that includes a first front wall portion 615 and a second front wall portion 617. The front wall and the back wall 112 of the housing 610 may be connected to each other via a first side wall 611 and a second side wall 613. According to embodiments herein, the first side wall 611 and the second side wall 613 may be parallel to each other.

[0090] A slit opening may be arranged between the first front wall portion 615 and the second front wall portion 617. Further, the charged particle device 600 may include a second electrode 620 arranged within the housing 610.

[0091] According to embodiments herein, the charged particle device may include an articulation element. For instance, the first side wall 611 may be attached moveable to the back wall 112 and/or the second side wall 613 may be attached moveable to the back wall 112. The articulation element 660 may for instance be a hinge-joint. The articulation element may allow the first side wall 611 and/or the second side wall 613 to rotate around an angle from 30° to 180° from an operative position of the first side wall 611 and/or the second side wall 613 respectively. According to embodiments herein, the articulation element may allow a rotation of at least 45° or at least 90° in order to, for instance, provide an easy access to the inside of the charged particle device for least partly exchanging the first portion of the second electrode 620. Not limited to any particular embodiment herein, the articulation element as described with respect to Fig. 6 and Fig. 7 may be arranged in any of the embodiments shown with respect to Fig. 1, Fig. 2 and Fig. 5.

[0092] Fig. 8 shows schematically a method for for increasing the extraction efficiency of a charged particle device according to embodiments herein. Generally, the method may be conducted with any of the charged particle devices and/or charged particle systems described herein.

[0093] For example, according to an embodiment, the method may include providing a charged particle device having: a housing providing a first electrode, the housing having a back wall and a front wall; a second electrode being arranged within the housing; a slit opening in the housing, and one or more beam shaping extensions that protrude from the second electrode in a direction towards the front wall portion of the housing. The method may further include igniting a plasma for producing charged particles from the second electrode of the charged particle device and guiding a beam of charged particles via the one or more beam shaping extensions through the slit opening of the charged particle device.

[0094] According to embodiments herein, guiding the charged particle beam may include focusing the charged particle beam via the one or more beam shaping extensions towards the slit opening. Optionally, guiding the charged particle beam may include focusing the charged particle beam via the one or more beam shaping extensions by an electric field towards the slit opening.

[0095] In yet further embodiments herein, the method for increasing the extraction efficiency of a charged particle device may include focusing a beam of charged particles towards the slit opening by the interaction of the charged particle beam with the electric field lines formed between the one or more beam shaping extensions and the front wall of the housing. Further, the method for increasing the extraction efficiency of a charged particle device may improve the life-time of the second electrode (e.g. the cathode) by reducing secondary emission.

[0096] Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. Any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.

[0097] This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the described subject-matter, including making and using any devices or systems and performing any incorporated methods. While various specific embodiments have been disclosed in the foregoing, those skilled in the art will recognize that the spirit and scope of the claims allows for equally effective modifications. Especially, mutually nonexclusive features of the embodiments described above may be combined with each other. The patentable scope is defined by the claims, and may include such modifications and other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.