WO2018141367A1

WO2018141367A1 - Method of processing a substrate and substrate carrier for holding a substrate

Info

Publication number: WO2018141367A1
Application number: PCT/EP2017/052051
Authority: WO
Inventors: Matthias HEYMANNS
Original assignee: Applied Materials, Inc.
Priority date: 2017-01-31
Filing date: 2017-01-31
Publication date: 2018-08-09
Also published as: KR101952718B1; KR20180101162A; TW201842556A; CN110199384B; CN110199384A; JP6533835B2; TWI684210B; JP2019508872A

Abstract

A method of processing a substrate (10) is described. The method includes attracting a substrate (10) to a support surface (102) of a substrate carrier (100) with a chucking device (120), arranging a mask (20) in front of the substrate (10), partially releasing the substrate (10) from the support surface (102), and depositing a material (105) on the substrate (10). According to a further aspect, a substrate carrier (100) for holding a substrate during deposition is described. The substrate carrier includes a chucking device (120) configured for attracting a substrate (10) toward a support surface (102) of the substrate carrier (100), wherein the chucking device (120) is configured to partially release the substrate (10) from the support surface (102).

Description

METHOD OF PROCESSING A SUBSTRATE

AND SUBSTRATE CARRIER FOR HOLDING A SUBSTRATE

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to the methods of processing a substrate. More specifically, the present disclosure relates to the deposition of a material on a substrate in a vacuum chamber, while the substrate is held on a support surface of a substrate carrier. Further embodiments relate to a substrate carrier for holding a substrate, and particularly to a substrate carrier with a chucking assembly configured for holding a substrate during the deposition of a material on the substrate in a vacuum chamber.

BACKGROUND

[0002] Opto-electronic devices that make use of organic materials are becoming increasingly popular for a number of reasons. Many of the materials used to make such devices are relatively inexpensive, so organic opto-electronic devices have the potential for cost advantages over inorganic devices. The inherent properties of organic materials, such as the flexibility of organic materials, may be advantageous for applications such as for deposition on flexible or inflexible substrates. Examples of organic opto-electronic devices include organic light emitting devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors.

[0003] For OLEDs, the organic materials may have performance advantages over conventional materials. For example, the wavelength at which an organic emissive layer emits light may be readily tuned with appropriate dopants. OLEDs make use of thin organic films that emit light when a voltage is applied across the device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, illumination, and backlighting. [0004] The substrate as well as a mask which defines a pattern to be provided on the substrate are often held on a respective support using mechanical forces. Conventional mechanical contacts used to hold the substrate and the mask during processing may result in substrate damage due to the applied mechanical force. The mechanical force may be applied to hold the mask in place during processing. The conventional mechanical carriers may hold the substrate at the edges, thus resulting in a highly concentrated physical contact at the edges of the substrate so as to ensure a sufficient clamping force. This mechanical contact concentrated at the edges of the substrate may create contact contamination or physical damage, degrading the substrate. [0005] Newer processing systems have incorporated alternative mechanisms for chucking the substrate to the substrate carrier that avoid the above described drawback. For example, the substrate is held in position by an electrostatic chuck using an electrostatic force. A contact force between components of the system and the substrate can be reduced.

[0006] However, a further mechanism is typically needed for holding the mask in front of the substrate during deposition, which may increase the handling complexity and may lead to positioning problems of the mask and/or of the substrate. For example, an accurate 3-dimensional positioning of the mask in front of the substrate, at a close distance to the substrate, without damaging the substrate, may be extremely challenging.

[0007] Accordingly, there is a need for a method and an apparatus for securely and exactly positioning a mask and a substrate in a processing system, while reducing the handling complexity.

SUMMARY

[0008] In light of the above, methods of processing a substrate, a substrate carrier for holding a substrate as well as a deposition apparatus for depositing a material on a substrate are provided.

[0009] According to one aspect of the present disclosure, a method of processing a substrate is provided. The method includes attracting a substrate to a support surface of a substrate carrier with a chucking device; arranging a mask in front of the substrate; partially releasing the substrate from the support surface; and depositing a material on the substrate.

[0010] According to a further aspect of the present disclosure, a substrate carrier for holding a substrate during deposition is provided. The substrate carrier includes a chucking device configured for attracting a substrate toward a support surface of the substrate carrier, and a second chucking device configured for attracting a mask toward the support surface of the substrate carrier, wherein the chucking device is configured to partially release the substrate from the support surface toward the mask during deposition.

[0011] According to a further aspect of the present disclosure, a deposition apparatus for depositing a material on a substrate is provided. The deposition apparatus includes a substrate carrier for holding a substrate during deposition according to any of the embodiments described herein, and a deposition source configured for depositing a material on the substrate held by the substrate carrier.

[0012] Further aspects, advantages and features of the present disclosure are apparent from the description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] 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 present 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. Typical embodiments are depicted in the drawings and are detailed in the description which follows.

[0014] FIG. 1 schematically shows stages (a) to (d) of a method of processing a substrate according to embodiments described herein; [0015] FIG. 2 is a schematic sectional view of a substrate carrier according to embodiments described herein;

[0016] FIG. 3 is a schematic front view of a substrate carrier according to embodiments described herein; [0017] FIG. 4 is a schematic sectional view of a substrate carrier according to embodiments described herein;

[0018] FIG. 5 is a schematic view of a deposition apparatus according to embodiments described herein; and [0019] FIG. 6 is a flow diagram illustrating a method of processing a substrate according to embodiments described herein.

DETAILED DESCRIPTION OF EMBODIMENTS

[0020] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. 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 any other embodiment to yield yet a further embodiment. It is intended that the present disclosure includes such modifications and variations.

[0021] Within the following description of the drawings, same reference numbers refer to the same or to similar components. Generally, only the differences with respect to the individual embodiments are described. Unless specified otherwise, the description of a part or aspect in one embodiment applies to a corresponding part or aspect in another embodiment as well.

[0022] FIG. 1 schematically illustrates stages (a) to (d) during the processing of a substrate 10 according to embodiments described herein.

[0023] In stage (a), a substrate 10 is attracted to a support surface 102 of a substrate carrier 100 with a chucking device 120, e.g. an electrostatic chuck. In FIG. 1, the substrate 10 is schematically depicted as a rectangle that is held on the support surface 102 of the substrate carrier 100. [0024] In stage (b), a mask 20 is arranged in front of the substrate 10. The mask may have an opening pattern in accordance with a material pattern that is to be deposited on a front surface of the substrate, while the back surface of the substrate 10 may be in direct contact with the support surface 102 of the substrate carrier. In some embodiments, the mask 20 may be fixed to a maskframe 25 in order to stabilize the mask.

[0025] In stage (c), the substrate 10 is partially released from the support surface. For example, the chucking device 120 may be configured to release a portion of the substrate from the support surface 102. Partially releasing the substrate from the support surface may have the effect that a gap 28 between the substrate 10 and the mask 20 may be at least partially reduced or removed.

[0026] In the embodiment shown in FIG. 1, an edge region 12 of the substrate is released from the support surface 102, e.g. by partially reducing a chucking force of the chucking device 120 or by partially deactivating the chucking device 120. The edge region 12 of the substrate 10 may detach from the support surface, e.g. due to gravity, and may bend toward the mask 20. In some embodiments, a full contact between the substrate and the mask can be established. For example, 90% or more of a front surface of the substrate, particularly the whole front surface of the substrate, may be contacted by the mask. [0027] In stage (d), a material 105 is deposited on the substrate. The substrate carrier 100 may be configured to support the substrate 10 during the deposition of the material on the substrate. Due to the decreased gap 28 between the mask and the substrate, a shadowing effect of the mask 20 may be reduced, and the quality of the deposited material pattern on the substrate may be improved. [0028] In some embodiments, which may be combined with other embodiments described herein, the substrate carrier 100 can be used to carry the substrate 10 through a vacuum chamber of a deposition apparatus that is described in more detail below. Details of the substrate carrier such as a transport device for moving the substrate carrier through the vacuum chamber are not shown in the figures. For example, the substrate carrier with the substrate held thereon may be moved into a vacuum chamber, where a material 105 is deposited on the substrate, whereupon the substrate carrier may be moved out of the vacuum chamber.

[0029] In some embodiments, which may be combined with other embodiments described herein, the substrate 10 may be held in an essentially vertical orientation at the support surface 102 at least temporarily during processing. For example, the substrate may be held in a substantially vertical orientation during transport through a vacuum chamber and/or during the deposition of the material on the substrate.

[0030] "Essentially vertical" as used herein may be understood as an orientation of the substrate, wherein the main surface of the substrate and the vertical direction (gravitational vector) enclose an angle between 0° and +/-20⁰, particularly between 0° and +/-10⁰ or less. The orientation of the substrate may not be (exactly) vertical during deposition, but slightly inclined with respect to the vertical axis, e.g. by an inclination angle of between 0° and -5°. A negative angle refers to an orientation in which the substrate faces slightly downward. This deviation from the vertical direction may be beneficial because a substrate orientation with some deviation from the vertical orientation might result in a more stable substrate deposition process, or a downward facing substrate orientation might be suitable for reducing particles on the substrate during deposition. However, an (exactly) vertical orientation (between -1° and +1° with respect to the vertical direction) is also possible. [0031] Accordingly, also the support surface 102 of the substrate carrier 100 may be essentially vertically oriented (+/- 20°) at least temporarily during the processing of the substrate. Holding a large area substrate in an essentially vertical orientation is challenging, because the substrate may bend due to the weight of the substrate, the substrate may slide down from the support surface in the case of an insufficient grip force of the chucking device 120, and/or the substrate may move with respect to the mask 20 which may be arranged in front of the substrate.

[0032] In some embodiments, the substrate may be held in an essentially horizontal orientation at least temporarily during processing, for example in a downward facing position. For example, the substrate may be held facing downward on an essentially horizontal support surface. A downward facing position of the substrate may be beneficial, in order to keep the particle uptake on the substrate surface at a minimum.

[0033] In some embodiments, the substrate carrier 100 may be movable, e.g. pivotable, between a vertical orientation and a non-vertical orientation, e.g. a horizontal orientation, and/or vice versa. For example, the substrate may be put on and attracted to the support surface 102 in a non-vertical orientation, the substrate carrier 100 with the attracted substrate may subsequently be moved, e.g. rotated, into the essentially vertical orientation, e.g. with a swing module, and the substrate may be transported and/or further processed in the essentially vertical orientation.

[0034] After processing, the substrate may be moved from an essentially vertical orientation to a non-vertical orientation, e.g. an essentially horizontal orientation, for example in a swing module. Thereafter the substrate may be released and removed from the support surface in the non-vertical orientation.

[0035] The substrate 10 may be held by the substrate carrier 100 during transport and/or during processing. For example, the substrate may be held by the substrate carrier during deposition, during transport of the substrate through a vacuum processing system, and/or during loading into and un-loading from one or more vacuum chambers.

[0036] One or more thin layers may be deposited on the substrate while the substrate is held at the substrate carrier. For example, a stack of layers, e.g. including at least one organic material, may be deposited on the substrate, e.g. by evaporation. [0037] According to embodiments of the present disclosure, an in-line or batch-type processing system with one or more transport devices can be used for transporting one or more substrate carriers together with a respective substrate along a transport path. In some implementations, the transport devices may be provided as a magnetic levitation system for holding the substrate carriers in a suspended state. Optionally, the in-line processing system can use a magnetic drive system configured for moving or conveying the substrate carriers along the transport path in a transport direction. The magnetic drive system can be included in the magnetic levitation system or can be provided as a separate entity.

[0038] In some implementations, a mechanical transport system may be provided. The transport system may include rollers for transporting the substrate carriers in the transport direction, wherein a drive for rotating the rollers may be provided. Mechanical transport systems may be easy to implement, robust, durable and maintenance friendly.

[0039] In some embodiments, the substrate 10 may be held at the support surface 102 of the substrate carrier 100 during the deposition of a coating material on the substrate. For example, chemical vapor deposition (CVD) systems, physical vapor deposition (PVD) systems, e.g. sputter systems, and/or evaporation systems were developed to coat substrates, e.g. thin glass substrates, e.g. for display applications, in a vacuum chamber. In typical vacuum processing systems, each substrate may be held by a substrate carrier, and the substrate carriers may be transported through the vacuum processing chamber by respective transport devices. The substrate carriers may be moved by the transport devices such that at least a part of the main surfaces of the substrates are exposed toward deposition sources, e.g. sputter devices or evaporator devices. The main surfaces of the substrates may be coated with thin material patterns while the substrates may be positioned in front of deposition sources which may move past the substrates at a predetermined speed. Alternatively, the substrates may be transported past the deposition sources at a predetermined speed.

[0040] The substrate 10 may be an inflexible substrate, e.g., a wafer, slices of transparent crystal such as sapphire or the like, a glass substrate, or a ceramic plate. However, the present disclosure is not limited thereto and the term substrate may also embrace flexible substrates such as a web or a foil, e.g. a metal foil or a plastic foil.

[0041] The substrate may be a large area substrate in some embodiments. A large area substrate may have a surface area of 0.5 m² or more. Specifically, a large area substrate may be used for display manufacturing and be a glass or plastic substrate. For example, substrates as described herein shall embrace substrates which are typically used for an LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), and the like. For instance, a large area substrate can have a main surface with an area of 1 m² or larger. In some embodiments, a large area substrate can be GEN 4.5, which corresponds to about 0.67 m² substrates (0.73 x 0.92m), GEN 5, which corresponds to about 1.4 m² substrates (1.1 m x 1.3 m), or larger. A large area substrate can further be GEN 7.5, which corresponds to about 4.29 m² substrates (1.95 m x 2.2 m), GEN 8.5, which corresponds to about 5.7m² substrates (2.2 m x 2.5 m), or even GEN 10, which corresponds to about 8.7 m² 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. In some implementations, an array of smaller sized substrates with surface areas down to a few cm², e.g. 2 cm x 4 cm and/or various individual shapes may be positioned on a single substrate carrier. [0042] In some implementations, a thickness of the substrate in a direction perpendicular to the main surface of the substrate may be 1 mm or less, e.g. from 0.1 mm to 1 mm, particularly from 0.3 mm to 0.8 mm, e.g. 0.7 mm. Even thinner substrates are possible. The handling of thin substrates with a thickness of 0.5 mm or less may be challenging. [0043] It may be beneficial with view to a good coating result to hold the substrate at the support surface 102 of the substrate carrier 100 such that movements of the substrate and/or of the mask during the deposition are avoided. An accurate positioning of the substrate on the support surface and with respect to the mask, and an accurate positioning of the mask with respect to the substrate becomes increasingly challenging, as the substrate sizes are increasing and the coating structures are decreasing.

[0044] In some embodiments, which may be combined with other embodiments described herein, the substrate is attracted to the support surface 102 with an electrostatic chuck which may be arranged in a carrier body 101 of the substrate carrier 100. In other words, the chucking device 120 that is configured to attract the substrate toward the support surface 102 may be an electrostatic chuck that is configured to attract the substrate 10 by electrostatic forces. By using an electrostatic chuck to attract the substrate to the support surface, a reliable and accurate positioning of the substrate on the substrate carrier is possible. The electrostatic chuck may be integrated in a carrier body 101 of the substrate carrier. [0045] The electrostatic chuck may also be referred to as an "e-chuck" herein. The substrate may be made of material that can be pulled toward the support surface by electrostatic forces such that the substrate can be brought into direct contact with the support surface. Holding of the substrate can be enabled also during high-temperature processes, coating processes and plasma processes also in a vacuum environment. [0046] In some embodiments, which may be combined with other embodiments disclosed herein, the carrier body 101 includes a dielectric body, wherein one or more electrodes of the electrostatic chuck are embedded in the dielectric body. The dielectric body can be fabricated from a dielectric material, e.g. a high thermal conductivity dielectric material such as pyrolytic boron nitride, aluminum nitride, silicon nitride, alumina or an equivalent material, e.g. a thermally resistant polymer based material such as a polyimide based material or other organic materials. The electrodes of the electrostatic chuck may be connected to a power supply, e.g. a voltage source, respectively, which may apply a predetermined voltage to the electrodes to generate a predetermined electrostatic grip force. [0047] However, the chucking device 120 is not limited to an electrostatic chuck, and may be a magnetic chuck and/or a mechanical chuck in other embodiments.

[0048] As is schematically depicted in stage (a) of FIG. 1, the chucking device 120 may be configured to hold the substrate slightly inclined downward at the support surface 102, e.g. at an angle with respect to the vertical axis between -1° and -5°. [0049] As is schematically depicted in stage (b) of FIG. 1, the mask 20 may be fixed to a maskframe 25 which may be configured to hold and stabilize the mask. For example, the mask 20 may be permanently attached to, e.g. welded to, the maskframe 25 at an edge of the mask 20. In some embodiments, the maskframe 25 partially or completely surrounds the mask. For example, the maskframe 25 may be formed as a frame which surrounds the mask and holds the mask at a circumferential edge of the mask.

[0050] As is schematically depicted in stage (d) of FIG. 1, the mask may be arranged at a close distance from the substrate in front of the substrate, i.e. between the substrate 10 and the deposition source 150. Due to gravity, the maskframe 25 may bend downward. The bending of the maskframe may lead to a gap 28 between the substrate and the mask, i.e. a gap 28 may result from a deformed maskframe as compared to the relatively stiff substrate carrier.

[0051] It may be difficult to compensate for the bending of the maskframe in the direction of gravity. The gap 28 between the mask and the substrate may result in a shadow in the deposited material pattern. More specifically, the edges of the material pattern that is deposited on the substrate may be negatively affected, e.g. blurred, and no sharp edges of the material pattern can be obtained.

[0052] According to embodiments described herein, the quality of the deposited material pattern can be improved by partially releasing the mask 20 from the substrate carrier with the chucking device 120. The chucking device 120 may be configured to reduce or to stop the chucking force in a part of the support surface, e.g. in an outer portion of the support surface where an edge region 12 of the substrate may be arranged.

[0053] As is schematically depicted in stage (c) of FIG. 1, the edge region 12 of the substrate 10 may be released from the support surface 102 with the chucking device 120 such that the edge region 12 can bend towards the mask 20, e.g. due to gravity. At the same time, a center region 11 of the substrate may be attracted to the support surface via the chucking device 120. However, the present disclose is not limited thereto, and an arbitrary region of the substrate can be released from the support surface during deposition, in order to decrease a distance between the substrate and the mask in said arbitrary region. [0054] It may be beneficial to attract the whole substrate to the support surface during the transport of the substrate, during the mask arrangement in front of the substrate, and/or during the mask removal from the substrate. Accordingly, when the mask is arranged in front of the substrate (in stage (b) of FIG. 1), both the edge region 12 of the substrate and the center region 11 of the substrate may be attracted to the support surface with the chucking device 120. A contact between the mask and the substrate during a relative movement of the mask and/or of the substrate can be reduced or avoided. In some embodiments, the edge region 12 of the substrate may again be attracted to the support surface 102 after the deposition of the material on the substrate, before the mask and the substrate are separated. [0055] In some embodiments, which may be combined with other embodiments described herein, the edge region 12 of the substrate which is released from the support surface 102 may have an edge width W of 5 mm or more and 50 mm or less, particularly an edge width from 10 mm to 20 mm. In some embodiments, an upper and/or a lower edge of the substrate in the direction of gravity is released from the substrate carrier (see stage (c) of FIG. 1). Alternatively or additionally, a left edge and a right edge of the substrate is released from the substrate carrier. In some embodiments, a circumferential edge region of the substrate, i.e. the upper edge, the lower edge, the left edge, and the right edge of the substrate are released from the support surface, e.g. respectively having an edge width from 10 mm to 20 mm. In some embodiments, only the upper edge and/or the lower edge of the substrate are released from the substrate carrier, e.g. having a respective edge width from 10 mm to 20 mm. [0056] During deposition of the material 105 on the substrate, only a first region of the substrate, e.g. the center region 11, may be attracted to the support surface 102, whereas a second region of the substrate, e.g. the edge region 12, may not be attracted. The first region may cover 75% or more, particularly 90% or more of the substrate surface. The edge region may cover 25% or less, particularly 10% or less of the substrate surface.

[0057] In some embodiments, which may be combined with other embodiments described herein, the chucking device 120 includes a main chucking zone 122 and at least one second chucking zone, particularly at least one edge chucking zone 124, which are operable independently of each other. The main chucking zone 122 may be configured and arranged for attracting and/or releasing a first region of the substrate, e.g. the center region 11, and/or the at least one second chucking zone may be configured and arranged for attracting and/or releasing a second region of the substrate, e.g. the edge region 12. Partially releasing the substrate 10 may include a deactivation of the at least one second chucking zone while activation of the main chucking zone 122 is maintained. [0058] In some embodiments, attracting the substrate 10 to the support surface 102 may include attracting the center region 11 of the substrate to the support surface 102 with an electrostatic main field of an electrostatic chuck, and/or partially releasing the substrate 10 may include deactivating one or more electrostatic edge fields of the electrostatic chuck for releasing the edge region 12 of the substrate 10 from the support surface 102. In some embodiments, the one or more electrostatic edge fields may surround the electrostatic main field. The electrostatic main field and the one or more electrostatic edge fields may be operated independently of each other, e.g. activated, deactivated, increased and/or decreased independently of each other. In particular, the e-chuck includes separate electrostatic fields, wherein only the electrostatic edge fields can be deactivated during decomposition.

[0059] By partially releasing the substrate 10 from the support surface, the gap 28 between the edge 22 of the mask and the edge region 12 of the substrate can reduced.

[0060] In some embodiments, arranging the mask 20 in front of the substrate 10 includes attracting the mask 20 toward the substrate 10 with a second chucking device, particularly with a magnetic chuck, more particularly with an electromagnetic chuck or with a chucking device including permanent magnets, e.g. with a magnet plate including one or more permanent magnets or electromagnets. By providing a chucking device 120 for attracting and releasing the substrate and a second chucking device 130 for attracting and releasing the mask, the mask and the substrate can be attracted and released independently of each other, and a correct and accurate positioning of the mask and/or of the substrate relative to each other can be facilitated.

[0061] In some embodiments, which may be combined with other embodiments described herein, an angle a between the vertical direction and the substrate 10 may be between 0° and -20°, particularly between -1° and -10°, more particularly between -1° and -5° during deposition. Particle generation on the substrate during deposition can be reduced or avoided.

[0062] FIG. 2 is a schematic sectional view of a substrate carrier 200 for holding a substrate during the deposition of a material on the substrate according to embodiments described herein. The substrate carrier 200 is configured to process a substrate according to any of the embodiments described herein and includes a chucking device 120, e.g. an electrostatic chuck, configured for attracting the substrate 10 toward the support surface 102 of the substrate carrier 100. The substrate carrier 200 further includes a second chucking device 130 configured for attracting a mask 20 toward the support surface 102 of the substrate carrier 100. [0063] The second chucking device 130 may be a magnetic chuck, particularly an electromagnetic chuck including one or more electromagnets, i.e. coils. However, the present disclosure is not limited thereto, and the second chucking device 130 may alternatively be a magnetic chuck including permanent magnets, an electrostatic chuck and/or a mechanical chuck. [0064] For example, the second chucking device 130 can be a plate including one or more permanent magnets, also referred to as a "magnetplate" herein. The magnetplate can be provided as a separate unit which can be movable with respect to the carrier body of the substrate carrier. The magnetplate may be arranged behind the carrier body of the substrate carrier. For example, a distance between the magnetplate and the mask can be adjusted by moving the magnetplate away from the carrier body or toward the carrier body on a rear side of the carrier body.

[0065] The chucking device 120 is configured to partially release the substrate 10 from the support surface 102 toward the mask 20. For example, prior to and/or during the deposition, the chucking device 120 may release a part of the substrate from the support surface. The released part of the substrate can bend toward the mask 20 which may be arranged in front of the substrate, e.g. due to the force of gravity. A gap 28 between the substrate and the mask may decrease. Accordingly, during deposition, a shadowing effect of the mask may be reduced and the deposition quality may increase. [0066] In some embodiments, which may be combined with other embodiments described herein, the chucking device 120 may be an electrostatic chuck including one or more electrodes and the second chucking device 130 device may be an electromagnetic chuck including one or more electromagnets.

[0067] The second chucking device 130 may be used to attract the mask 20 and/or the maskframe 25 toward the substrate 10 which is held on the support surface 102. For example, the mask 20 can be attracted toward the support surface 102 with the second chucking device 130 such that at least a portion of the mask 20 is brought into direct contact with the substrate 10. Shadowing effects can be reduced. After deposition, the second chucking device 130 may release the mask 20 from the substrate 10 so that the mask and the substrate can be separated from each other without negatively affecting the material pattern deposited on the substrate.

[0068] In some embodiments, the mask 20 includes a magnetically attractable material, e.g. a metal, so that the mask can be attracted with magnetic forces which are generated by a magnetic chuck. For example, the mask 20 is a metal mask, particularly a fine metal mask. In some embodiments, also the maskframe 25 may include a magnetically attractable material, e.g. a metal, so that also the maskframe can be attracted toward the support surface by magnetic forces. The mask 20 may be fixed to the maskframe 25, e.g. permanently fixed to the maskframe 25 by welding. For example, the maskframe 25 may be formed as a frame which surrounds the mask and holds the mask at a circumferential edge of the mask. [0069] The complexity of the substrate carrier may be decreased and the handling can be simplified, when the chucking device 120, e.g. the electrostatic chuck, and the second chucking device 130, e.g. the magnetic chuck, are integrated in a carrier body 101 of the substrate carrier 100. For example, the chucking device 120 may be embedded in a first inner volume of the carrier body 101, and the second chucking device 130 may be embedded in a second inner volume of the carrier body 101. Alternatively or additionally, the chucking device 120 and the second chucking device 130 are firmly connected to the same carrier, e.g. by attaching both the chucking device 120 and the second chucking device 130 to the same carrier body 101, so that both chucking devices can be transported and moved as a single unit.

[0070] In other embodiments, the chucking device 120 may be arranged in the carrier body 101 of the substrate carrier, and the second chucking device 130 may be provided in a separate body which may be movable with respect to the substrate carrier. For example, a magnetic chuck may be provided in a separate body that can be positioned at a back side of the substrate carrier during deposition. The distance between the substrate carrier and the separate body may be adjustable, in order to adjust a magnetic force at the position of the mask.

[0071] The chucking device 120 may include two or more chucking zones which may be operated independently of each other. For example, a first chucking zone, e.g. a main chucking zone 122, may be activated and/or deactivated independently of at least one second chucking zone, e.g. at least one edge chucking zone 124. The main chucking zone 122 may provide a chucking force that is sufficient for attracting the substrate to the support surface, e.g. even when the at least one second chucking zone is deactivated. The at least one second chucking zone may be deactivated for releasing a part of the substrate, e.g. an edge of the substrate, from the support surface.

[0072] In some embodiments, which may be combined with other embodiments described herein, the chucking device 120 is an electrostatic chuck including a main chucking zone 122 configured for generating an electrostatic main field and one or more edge chucking zones 124 configured for generating one or more electrostatic edge fields. The main chucking zone 122 may provide an electrostatic force that is sufficient for attracting the substrate to the support surface, even when the one or more edge chucking zones 124 are deactivated. The one or more edge chucking zones 124 may be deactivated for releasing an edge part of the substrate from the support surface.

[0073] The main chucking zone 122 may be configured for attracting the center region 11 of the substrate and/or may be arranged in a center part of the carrier body 101. The one or more edge chucking zones 124 may be configured for attracting and releasing the edge region of the substrate and/or may be arranged in a peripheral part of the carrier body 101, e.g. surrounding the main chucking zone 122.

[0074] For example, the one or more edge chucking zones 124 may include a first edge chucking zone configured for attracting at least one of an upper edge and a lower edge of the substrate and/or a second edge chucking zone that is configured for attracting at least one of a left edge and a right edge of the substrate.

[0075] In some embodiments, the main chucking zone 122, the first edge chucking zone and the second edge chucking zone are separate chucking zones that are operable independently from each other. For example, the main chucking zone 122 may remain activated during the deposition of a material on the substrate, whereas one or more edge chucking zones 124 may be deactivated during deposition, in order to release at least a part of the substrate toward the mask.

[0076] FIG. 3 shows a substrate carrier 300 in a schematic front view. The substrate carrier 300 may include some or all of the features of any of the embodiments described herein so that reference can be made to the above explanations which are not repeated here.

[0077] As is depicted in more detail in the front view of FIG. 3, the one or more edge chucking zones 124, e.g. the first edge chucking zone and the second edge chucking zone, may include a plurality of electrodes that are arranged to form a frame which surrounds the main chucking zone 122. The size of the chucking device 120 may be adapted to the size of the substrate. The main chucking zone 122 may be arranged in a center part of the carrier body 101 of the substrate carrier 300 and/or may cover 50% or more, particularly 75% or more of a surface area of the chucking device 120. The one or more edge chucking zones 124 may cover 25% or less, particularly 10% or less, of the surface of the chucking device. For example, a width W of an upper chucking zone and/or of a lower chucking zone may be 5 mm or more and 50 mm or less, particularly 10 mm or more and 20 mm or less, in a vertical direction, respectively. Alternatively or additionally, a width of a left chucking zone and/or of a right chucking zone may be 5 mm or more and 50 mm or less, particularly 10 mm or more and 20 mm or less, in a left-right direction, respectively. Each chucking zone may include one or more electrodes, e.g. alternately charged wires.

[0078] FIG. 4 is a schematic sectional view of a substrate carrier 400 according to embodiments described herein. The substrate carrier 400 may be similar to the substrate carrier 200 depicted in FIG. 2 so that reference can be made to the above embodiments which are not repeated here. The chucking device 120 may be configured as an electrostatic chuck including one or more electrodes 410. The one or more electrodes 410 may be configured to generate a predetermined electrostatic grip force, which may be adjustable. The one or more electrodes 410 may be connected to a first power supply 420, e.g. a high voltage supply for applying a high voltage to the one or more electrodes 410.

[0079] The electrostatic chuck may be configured as a monopolar chuck, as a bipolar chuck or as a multi-pole chuck. A "monopolar chuck" may be understood as an electrostatic chuck including one or more electrodes connectable to a power supply, e.g. a high voltage source. The power supply is configured to provide an electric voltage of a single polarity to the one or more electrodes.

[0080] A "bipolar chuck assembly" as used herein may be understood as an electrostatic chuck including at least one first electrode and at least one second electrode connectable to the power supply, e.g. a high voltage source. The power supply is configured to provide an electric voltage of a first polarity to the first electrodes and an electric voltage of a second polarity to the second electrodes. For example, a negative voltage may be applied to the first electrodes, and a positive voltage may be applied to the second electrodes, or vice versa. Accordingly, corresponding negatively charged regions and corresponding positively charged regions may be generated at the support surface by electrostatic induction. In some embodiments, a symmetric bipolar voltage is provided.

[0081] In a multi-pole chuck assembly, a plurality of electrodes may be provided which may be independently controllable. [0082] Separate electric connection lines and/or supply terminals may be provided for powering the main chucking zone 122 and the one or more edge chucking zones 124.

[0083] The electrostatic chuck shown of FIG. 4 includes at least one first electrode and at least one second electrode, wherein a positive voltage (+) is applied to the first electrode and a negative voltage (-) is applied to the second electrode by the first power supply 420, e.g. a high voltage source. The at least one first electrode may be interleaved with the at least one second electrode, in order to increase the grip force provided by the electrostatic chuck. Alternatively or additionally, first electrodes and second electrodes may be alternately arranged. For example, the electrostatic chuck may include a plurality of wires which are positively and negatively charged in an alternate way.

[0084] In some embodiments, the main chucking zone 122 includes alternately chargeable electrodes, particularly alternately chargeable wires, and/or the at least one edge chucking zone 124 includes alternately chargeable electrodes, particularly alternately chargeable wires. The first power supply 420 may be configured to power the electrodes of the main chucking zone 122 independently of the electrodes of the at least one edge chucking zone 124.

[0085] In some embodiments, the second chucking device 130 is an electromagnetic chuck including one or more electromagnets 412 for generating a magnetic field. A second power supply 430 may be provided for powering the one or more electromagnets 412. Electric connection lines 431 may be provided for connecting the second power supply 430 with respective coil windings (not shown in FIG. 4) of the one or more electromagnets 412. The polarities of adjacent electromagnets directed toward the support surface may be opposite in some embodiments. In particular, the electromagnets may be arranged such that the polarities of respective neighboring electromagnets directed toward the support surface are opposite polarities. For example, the windings of adjacent electromagnets may be inverted, respectively, so that an alternate arrangement of windings is provided, as is depicted in FIG. 4.

[0086] The first power supply 420 and the second power supply 430 may be integrated as a single power supply with different output terminals for separately and independently powering the chucking device 120 and the second chucking device 130. [0087] The chucking device 120 and the second chucking device 130 may be operated independently and/or may be controlled by a controller unit which may be configured to control the timings for chucking the mask, the timings for chucking the substrate, the timings for releasing the mask, the timings for releasing the substrate, a chucking force of the substrate and/or a chucking force of the mask. Further, the controller unit may be configured to control the respective timings of the main chucking zone 122 and the at least one edge chucking zone 124 of the chucking device 120.

[0088] In some embodiments, which may be combined with other embodiments described herein, the one or more electromagnets 412 of the magnetic chuck may be arranged at a first distance from the support surface 102. The first distance between the one or more electromagnets 412 and the support surface 102 may be 10 cm or less, particularly 5 cm or less, more particularly 2 cm or less. The magnetic force at the position of the mask can be increased by providing a small first distance.

[0089] FIG. 5 is a schematic view of a deposition apparatus 500 for depositing a material on a substrate according to embodiments described herein. The deposition apparatus 500 includes a substrate carrier 100 for holding a substrate 10 according to any of the embodiments described herein, and a deposition source 150, e.g. an evaporation device, configured for depositing a material 105 on the substrate 10 that is supported on the substrate carrier. [0090] In some embodiments, the deposition apparatus 500 further includes a mask carrier that is configured to transport the mask 20 so that the mask can be arranged in front of the substrate 10. In particular, the mask carrier may be configured to transport a maskframe 25 and a mask 20 that is fixed to the maskframe 25.

[0091] The deposition apparatus 500 may further include a vacuum chamber 501, wherein the deposition source 150 and the substrate carrier 100 are arranged in the vacuum chamber 501. The deposition source 150 may be an evaporation device including a crucible for housing a material that is to be evaporated and at least one distribution pipe for guiding the evaporated material toward a plurality of openings in the distribution pipe, which are directed toward the substrate 10 during deposition. [0092] The deposition source 150 may be provided on a movable support so that the deposition source 150 can be moved past the substrate 10 during the deposition.

[0093] The substrate is attracted to the support surface of the substrate carrier with the chucking device 120, and the mask 20 is attracted toward the support surface with the second chucking device 130. In some embodiments, the chucking device 120 and the second chucking device 130 are integrated in a carrier body of the substrate carrier. The chucking device 120 may include a plurality of chucking zones configured to provide independently controllable electrostatic fields.

[0094] The second chucking device 130 may be a magnetic chuck including a plurality of chucking zones, wherein at least one first chucking zone 132 may be configured for attracting a center part of the mask and at least one second chucking zone 134 may be configured for attracting the maskframe 25 and/or an outer part of the mask. A gap between the edge 22 of the mask and the substrate can be reduced by setting the magnetic force of the at least one second chucking zone 134 to an appropriate value, which may be different from the value of the magnetic force of the at least one first chucking zone 132. For example the maskframe 25 may be attracted with a higher magnetic force than a center part of the mask. In particular, the at least one first chucking zone 132 and the at least one second chucking zone 134 may be independently controlled.

[0095] FIG. 6 is a flow diagram for illustrating a method of processing a substrate according to embodiments described herein. In box 610, a substrate is attracted toward a support surface of a substrate carrier with a chucking device 120, e.g. with an electrostatic chuck that is integrated in a carrier body of the substrate carrier. The complete substrate may be attracted to the substrate carrier.

[0096] For example, the substrate may be put onto the support surface in a non-vertical orientation, whereupon the chucking device may be activated, and the substrate carrier may be rotated, e.g. to an essentially vertical orientation (+/- 20°).

[0097] When the substrate is held at the support surface of the substrate carrier, the substrate carrier may be transported within a vacuum processing system, e.g. into a vacuum chamber of a deposition apparatus. For example, the substrate carrier may be moved with the substrate into the deposition apparatus, wherein a deposition source may be arranged in the deposition apparatus.

[0098] In box 620, a mask 20 is arranged in front of the substrate. The mask may be aligned with respect to the substrate so that a predetermined relative position between the substrate and the mask is established. For example, a rough alignment and a subsequent fine alignment may ensure that a position deviation between the mask and the substrate in an up-down direction and/or in a left-right direction is 10 μηι or less, particularly 3 um or less, respectively.

[0099] In box 630, the mask 20 and/or a maskframe 25 that holds the mask may be attracted toward the support surface with a second chucking device 130, e.g. with a magnetic chuck, for example an electromagnetic chuck that is integrated in the carrier body of the substrate carrier. For example, at least a portion of the mask may be pulled toward the substrate such that the mask comes into direct contact with the substrate.

[00100] In box 640, at least a part of the substrate is released from the support surface, e.g. by partially deactivating the chucking device 120. In some embodiments, an edge of the mask 20 is fixed to the maskframe 25, and a gap between the edge 22 of the mask and the substrate is reduced by partially releasing the substrate. The released part of the substrate may move toward the mask, e.g. due to the force of gravity.

[00101] In box 650, a material may be deposited on the substrate, e.g. with an evaporation device. When the mask is arranged in front of the substrate, a material pattern according to an opening pattern of the mask may be formed on the substrate.

[00102] After deposition, the released part of the substrate may be again attracted toward the support surface with the chucking device, e.g. in order to avoid a damage of the deposited material pattern.

[00103] The mask may be released from the substrate by at least partially deactivating the second chucking device. The mask and the substrate may be separated. [00104] Thereupon, the substrate may be transferred out of the deposition apparatus and/or may be de-chucked and removed from the support surface, e.g. by deactivating the second chucking device.

[00105] The material may be deposited on the substrate, while an angle a between the vertical direction and the substrate is between 0° and -20°, particularly between -1° and -5° during deposition. In particular, the substrate may be arranged in a downwardly inclined way at an angle between -1° and -5° during deposition.

[00106] While the foregoing is directed to embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A method of processing a substrate (10), comprising: attracting a substrate (10) to a support surface (102) of a substrate carrier (100) with a chucking device (120); arranging a mask (20) in front of the substrate (10); partially releasing the substrate (10) from the support surface (102); and depositing a material on the substrate (10).

2. The method of claim 1, wherein partially releasing the substrate (10) from the support surface (102) comprises releasing an edge region (12) of the substrate (10) from the support surface.

3. The method of claim 2, wherein the edge region (12) has an edge width (W) of 5 mm or more and 50 mm or less.

4. The method of any of claims 1 to 3, wherein the chucking device (120) comprises a main chucking zone (122) and at least one second chucking zone, particularly at least one edge chucking zone (124), which are operable independently from each other, wherein partially releasing the substrate (10) comprises deactivating the at least one second chucking zone while an activation of the main chucking zone (122) is maintained.

5. The method of any of claims 1 to 4, wherein the substrate (10) is attracted to the support surface (102) with an electrostatic chuck provided in a carrier body (101) of the substrate carrier (100).

6. The method of claim 5, wherein attracting the substrate (10) to the support surface (102) comprises attracting a center region (11) of the substrate to the support surface with an electrostatic main field of the electrostatic chuck, and/or wherein partially releasing the substrate (10) comprises deactivating one or more electrostatic edge fields of the electrostatic chuck for releasing an edge region (12) of the substrate (10) from the support surface (102).

7. The method of any of claims 1 to 6, wherein an edge (22) of the mask (20) is fixed to a maskframe (25), and wherein a gap (28) between the edge (22) of the mask and the substrate is reduced by partially releasing the substrate (10).

8. The method of any of claims 1 to 7, wherein arranging the mask (20) in front of the substrate (10) comprises attracting the mask (20) toward the substrate (10) with a second chucking device (130), particularly with a magnetic chuck, more particularly with an electromagnetic chuck or with a chucking device comprising permanent magnets.

9. The method of any of claims 1 to 8, wherein an angle (a) between a vertical direction and the substrate (10) is between 0° and -20°, particularly between -1° and -5° during deposition.

10. A substrate carrier (100) for holding a substrate during deposition, comprising: a chucking device (120) configured for attracting a substrate (10) toward a support surface (102) of the substrate carrier (100); and a second chucking device (130) configured for attracting a mask (20) toward the support surface ( 102) of the substrate carrier ( 100), wherein the chucking device (120) is configured to partially release the substrate (10) from the support surface (102) toward the mask (20) during deposition.

11. The substrate carrier of claim 10, wherein the chucking device (120) is an electrostatic chuck and/or the second chucking device (130) is a magnetic chuck.

12. The substrate carrier of claim 10 or 11, wherein the chucking device (120) is an electrostatic chuck comprising a main chucking zone (122) configured for generating a electrostatic main field and at least one edge chucking zone (124) configured for generating one or more electrostatic edge fields.

13. The substrate carrier of claim 12, wherein the main chucking zone (122) and the at least one edge chucking zone (124) comprise alternately chargeable electrodes, particularly alternately chargeable wires, respectively.

14. The substrate carrier of claim 12 or 13, wherein the main chucking zone (122) is configured for attracting a center region (11) of the substrate, a first edge chucking zone is configured for attracting at least one of an upper edge and a lower edge of the substrate, and/or a second edge chucking zone is configured for attracting at least one of a left edge and a right edge of the substrate.

15. A deposition apparatus (500) for depositing a material on a substrate, comprising: a substrate carrier (100) for holding a substrate (10) during deposition according to any of claims 10 to 14; and a deposition source (150) configured for depositing a material (105) on the substrate (10) held by the substrate carrier.