WO2020046737A1

WO2020046737A1 - Method and device for vapor deposition of functional coating

Info

Publication number: WO2020046737A1
Application number: PCT/US2019/047865
Authority: WO
Inventors: Jae-Chang Lee
Original assignee: Corning Inc
Current assignee: Corning Inc
Priority date: 2018-08-31
Filing date: 2019-08-23
Publication date: 2020-03-05
Anticipated expiration: 2021-02-28
Also published as: KR20200025952A

Abstract

A coating device for forming a functional coating on a substrate and a substrate clamping device and method applied to the coating device. The substrate clamping device includes a gasket configured to fix a substrate to be coated and including an adsorbing surface, to which the substrate is attached, and a clamping jaw around at least portion of the adsorbing surface, the clamping jaw being a dam type and fixing the substrate to the adsorbing surface through thermal expansion; and a jaw supporter adjacent to the clamping jaw and configured to support the clamping jaw to direct the thermal expansion of the clamping jaw toward the substrate.

Description

METHOD AND DEVICE FOR VAPOR DEPOSITION OF FUNCTIONAL COATING

BACKGROUND

[0001] This application claims the benefit of priority under 35 U.S.C. § 1 19 of Korean Patent Application Serial No. 10-2018-0104025, filed on August 31 , 2018, the content of which is relied upon and incorporated herein by reference in its entirety.

1. Field

[0002] One or more embodiments relate to a functional coating method and device for a substrate, and more particularly, to a functional coating method and device for suppressing contamination of a substrate.

2. Description of the Related Art

[0003] When a functional coating is deposited on glass panels or covers, for example covers of smartphones or smartwatches, meta-mode sputtering is usually used so that the functional coating is simultaneously deposited on a plurality of panels.

[0004] In the meta-mode sputtering, coating is performed in a state where a plurality of substrates are vertically or horizontally attached to a rotary drum in a sputtering chamber. At this time, the substrates are attached to the rotary drum using a gripper, which is a mechanical holding device, or a silicon heat-resistant adhesive tape.

[0005] When the gripper is used during the coating, coating quality may be locally deteriorated due to fingers holding a panel. When the adhesive tape is used, the adhesive tape is expensive and adhesive substances remain in a substrate and thus need to be washed away.

SUMMARY

[0006] One or more embodiments include a method of efficiently clamping a substrate to be coated, and a substrate coating device and substrate clamping device using the same. [0007] One or more embodiments include a method of clamping a substrate so as to prevent the substrate from being contaminated by foreign substances, and a substrate coating device and substrate clamping device using the same.

[0008] One or more embodiments include a method of clamping a substrate so as to form a high-quality coating on the substrate, and a substrate coating device and substrate clamping device using the same.

[0009] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

[0010] According to one or more embodiments, a substrate clamping device includes a gasket configured to hold a substrate to be coated and including an adsorbing surface, to which the substrate is attached, and a clamping jaw around at least portion of the adsorbing surface, the clamping jaw being a dam type and fixing the substrate to the adsorbing surface through thermal expansion; and a jaw supporter opposite the substrate with the clamping jaw between the jaw supporter and the substrate and configured to support the clamping jaw to direct the thermal expansion of the clamping jaw toward the substrate.

[0011] The clamping jaw may be integrally formed with the adsorbing surface.

[0012] The gasket may further include at least one well-type pocket configured to accommodate the substrate, the well-type pocket including the adsorbing surface on a bottom and the clamping jaw around the adsorbing surface, the clamping jaw being defined as a wall having a predetermined height corresponding to a side surface of the substrate.

[0013] The substrate clamping device may further include a mounting plate including a gasket mount on which the gasket is mounted, wherein the gasket mount may be a well type and may include the jaw supporter.

[0014] The substrate clamping device may further include a complementary locking portion in a back surface of the gasket and a bottom surface of the gasket mount.

[0015] The complementary locking portion may include a protrusion-type complementary locking portion in the back surface of the gasket; and a well- or slit-type complementary locking portion in the bottom surface of the gasket mount, the well- or slit-type complementary locking portion being coupled to the protrusion-type complementary locking portion.

[0016] An inner surface of the clamping jaw may be configured to be separated from an edge of the substrate by a predetermined spacing at a room temperature, and when the clamping jaw is thermally expanded, a back portion of the clamping jaw may be supported by the jaw supporter and a front portion thereof may press a side surface of the substrate.

[0017] The adsorbing surface may include a break portion configured to absorb horizontal expansion of the adsorbing surface to prevent distortion of the adsorbing surface.

[0018] The clamping jaw may be discontinuously formed around the adsorbing surface.

[0019] The substrate clamping device may further include a base plate on which the mounting plate is mounted.

[0020] A recess may be formed in the adsorbing surface, the recess corresponding to a decoration layer formed on the substrate.

[0021] According to one or more embodiments, a substrate coating device includes a vacuum chamber, with a sputter target and a plasma source disposed in the vacuum chamber; a vacuum system connected to the vacuum chamber; a rotary drum installed in the vacuum chamber; and a substrate clamping device configured to mount a substrate on the rotary drum. The substrate clamping device may include a gasket configured to hold the substrate and including an adsorbing surface, to which the substrate is attached, and a clamping jaw around at least portion of the adsorbing surface, the clamping jaw being a dam type and fixing the substrate to the adsorbing surface through thermal expansion; and a jaw supporter provided opposite the substrate with the clamping jaw between the jaw supporter and the substrate and configured to support the clamping jaw to direct the thermal expansion of the clamping jaw toward the substrate.

[0022] According to one or more embodiments, a method of clamping a substrate includes preparing a gasket capable of holding the substrate, attaching the substrate to the gasket at a room temperature using a molecular force, and increasing a temperature of the gasket to mechanically clamp the substrate. [0023] The gasket may include an adsorbing surface to which the substrate is attached; and a clamping jaw configured to mechanically clamp a side surface of the substrate when the temperature is increased, the clamping jaw protruding along an edge of the adsorbing surface and being a dam type.

[0024] A side surface of the clamping jaw may be separated from an edge of the substrate by a predetermined spacing in the attaching of the substrate.

[0025] The clamping jaw may be thermally expanded to contact and press the side surface of the substrate in the increasing of the temperature of the gasket.

[0026] The method may further include fixing the gasket to a mounting plate before the increasing of the temperature of the gasket, wherein the mounting plate may include a jaw supporter configured to support the clamping jaw at a side of the clamping jaw.

[0027] The mounting plate may be configured to hold a plurality of gaskets.

[0028] The adsorbing surface may include a break portion, and the molecular force may be maintained when the adsorbing surface is thermally expanded in the increasing of the temperature of the gasket.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

[0030] FIG. 1 is a schematic diagram of a meta-mode sputtering apparatus forming a functional thin film on a glass substrate, according to some embodiments;

[0031] FIG. 2 is a diagram of a substrate clamping device on which a single substrate is mounted, according to some embodiments;

[0032] FIG. 3 is a diagram of a substrate clamping device on which a plurality of substrates are mounted, according to some embodiments;

[0033] FIG. 4 is an exploded perspective view of the substrate clamping device of FIG. 3, according to some embodiments;

[0034] FIG. 5 is a perspective view of a back surface of a base plate used in the substrate clamping device of FIG. 4; [0035] FIG. 6 is a perspective view of a top surface of a gasket applied to a substrate clamping device, according to some embodiments;

[0036] FIG. 7 is a perspective view showing a bottom surface of a gasket applied to a substrate clamping device, according to some embodiments;

[0037] FIG. 8 is a partial cross-sectional view taken at l-l of FIG 4 of the substrate clamping device, on which a gasket with a substrate mounted thereon is mounted, according to some embodiments;

[0038] FIG. 9 is an enlarged view of a portion B in FIG. 8;

[0039] FIG. 10 is a diagram of circular cover glass (or a substrate) used in a smartwatch or the like;

[0040] FIG. 1 1 is a perspective view of a top surface of a circular gasket, on which a circular cover glass may be mounted, according to some embodiments;

[0041] FIG. 12 is a perspective view of a bottom surface of the circular gasket of FIG. 1 1 , according to some embodiments; and

[0042] FIG. 13 is a partial cross-sectional view of a substrate clamping device, on which a circular gasket is mounted, according to some embodiments.

DETAILED DESCRI PTION

[0043] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Rather, these embodiments are provided so that the scope of the present disclosure will be fully conveyed to those skilled in the art. Like numbers refer to like elements throughout. In the drawings, elements and regions are schematically illustrated. Accordingly, the scope of the present disclosure is not limited by relative sizes or gaps illustrated in the drawings.

[0044] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first signal could be termed a second signal, and, similarly, a second signal could be termed a first signal without departing from the teachings of the disclosure. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well , unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," or "includes" and/or "including" when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, and/or combinations thereof, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or combinations thereof. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present application, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0045] When it is possible to modify an embodiment, the order of processes may be different from the order in which the processes have been described. For instance, two processes described as being performed sequentially may be substantially performed simultaneously or in a reverse order.

[0046] In the drawings, transformation of the shapes may be expected according to, for example, manufacturing techniques and/or tolerance. Accordingly, embodiments should not be construed as being limited to specified shapes in the drawings but as including changes in the shapes occurring during, for example, manufacturing processes. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

[0047] FIG. 1 is a schematic diagram of a meta-mode sputtering apparatus 10 forming a functional thin film on a glass substrate, according to some embodiments.

[0048] Referring to FIG. 1 , a vacuum system 15 is connected to a chamber 1 1 of the meta-mode sputtering apparatus 10. A drum 14, which rotates, is provided in the chamber 1 1. A plurality of substrate clamping devices 20 are fixed to a lateral outer circumference of the drum 14. A substrate, which will undergo a thin layer coating process, is mounted on each of the substrate clamping devices 20.

[0049] A sputter target 12 is provided on one side (e.g., at the left side of FIG. 1 ) of the drum 14, which has a rotation shaft 14a, and a plasma source 13 is provided on an opposite side (e.g., at the right side of FIG. 1 ).

[0050] The thin layer coating process is performed on the substrate in the substantially the same manners in usual meta-mode sputtering.

[0051] Various functional coatings may be applied to cover glass used in devices, such as smartphones and smartwatches, to increase user convenience. Anti -reflection (AR) coating, easy-to-clean (ETC) coating, scratch resistant coating (SRC), etc. have been applied to cover glass for smart devices.

[0052] The substrate is a target of a thin layer coating process and may be cover glass for smartphones or smartwatches. Various functional coatings may be formed on a surface of the cover glass to increase user convenience. An AR coating, an ETC coating, and an SRC are typical functional coatings.

[0053] FIGS. 2 and 3 are each diagrams of a substrate clamping device 20 on which a substrate, e.g., cover glass, to undergo a coating process is mounted. FIG. 2 shows a structure in which a single substrate 1 is mounted on the substrate clamping device 20. FIG. 3 shows a structure in which a plurality of substrates 1 are mounted on the substrate clamping device 20.

[0054] FIG. 4 is an exploded perspective view of the substrate clamping device 20 on which the plurality of substrates 1 are mounted, according to some embodiments. FIG. 5 is a perspective view of a back surface of a base plate 21 used in the substrate clamping device 20.

[0055] Referring to FIG. 4, a mounting plate 22 is fixed to the base plate 21. A plurality of gaskets 23 are mounted on the mounting plate 22. The base plate 21 is directly fixed to a deposition apparatus. Two fixing bosses 21 1 are respectively formed in upper and lower portions of a back surface of the base plate 21 , as shown in FIG. 5. The base plate 21 is fixed to the deposition apparatus using the fixing bosses 21 1 . [0056] The base plate 21 may be selectively provided to support the mounting plate 22. In one or more embodiments, the mounting plate 22 may include the function of the base plate 21 and may be directly fixed to the deposition apparatus.

[0057] A plurality of gasket mounts 221 are formed in the mounting plate 22. Each of the gasket mounts 221 may have a form of a shallow rectangular well to fit to a rectangular shape of a gasket 23. A protrusion-type complementary locking portion may be provided in a back surface of the gasket 23, and a well- or slit-type complementary locking portion may be provided in a bottom surface of each gasket mount 221 . The protrusion- type complementary locking portion is coupled to the well- or slit-type complementary locking portion.

[0058] In some embodiments, as an element of a complementary locking portion provided to stably fix the gasket 23 to the gasket mount 221 , a slit 221a may be formed in the bottom surface of the gasket mount 221. As another element of the complementary locking portion, a foot 231 corresponding to the slit 221 a may be formed in the back surface of the gasket 23. In one or more embodiments, the gasket mount 221 may have other suitable shapes, for example a form of a shallow circular well, and correspondingly, the gasket 23 may have a circular shape.

[0059] The gasket 23 holding the substrate 1 has a form of a frame enclosing all or a portion of the edge of the substrate 1 and has a structure of a pocket in which the substrate 1 is inserted and fixed. The pocket includes a clamping jaw 232 having a form of a dam and an adsorbing surface 233 surrounded by the clamping jaw 232. In detail, the clamping jaw 232, which has a form of a frame or a dam and clamps the edge of the substrate 1 , protrudes along an edge of the adsorbing surface 233, on which the substrate 1 is seated, to have a predetermined height. The adsorbing surface 233 at an inner side of the clamping jaw 232 is a van der Waals (VDW) adsorbing surface which holds the substrate 1 using a VDW force. The clamping jaw 232 having the form of a dam mechanically fixes the substrate 1 to the adsorbing surface 233 due to thermal expansion.

[0060] In other words, in some embodiments, when a substrate clamping device fixes a substrate in a chamber, the substrate clamping device primarily fixes the substrate to an adsorbing surface using a molecular force and secondarily fixes the substrate using a mechanical force produced by expansion of a clamping jaw at a high temperature in the chamber. Such a substrate fixing mechanism will be easily understood from descriptions below.

[0061] FIG. 6 is a perspective view of a top surface of the gasket 23. FIG. 7 is a perspective view showing a bottom surface of the gasket 23. A portion A in FIG. 6 shows an example of a discontinuous formation of the clamping jaw 232 in one or more embodiments.

[0062] Referring to FIGS. 6 and 7, a pocket is formed in the gasket 23. The pocket is defined by the adsorbing surface 233, which contacts an edge portion of a back surface of the substrate 1 , and the clamping jaw 232, which has the form of a wall or a dam along the edge of the adsorbing surface 233. The adsorbing surface 233 primarily holds the substrate 1 using a VDW force. The clamping jaw 232 presses the edge of the substrate 1 in a horizontal direction, which is parallel to a main surface of the substrate 1 , due to thermal expansion and thus fixes the substrate 1 to the gasket 23.

[0063] The clamping jaw 232 may become to contact and press the edge of the substrate 1 due to thermal expansion, and in some instances due to only thermal expansion. Accordingly, when the the inner side (or inner perimeter) of the clamping jaw 232 is wider than a bottom surface (or outer perimeter) of the substrate 1 facing the adsorbing surface 233, the substrate 1 may be easily inserted in and separated from the gasket 23 in a state where the gasket 23 is fixed to the mounting plate 22.

[0064] The adsorbing surface 233 of the gasket 23 may be disposed along the edge of the substrate 1. In one or more embodiments, the adsorbing surface 233 may be sized to correspond to the entire surface, or a part of the surface, of the substrate 1. The clamping jaw 232 may entirely enclose, or partially enclose, the edge of the substrate 1. In one or more embodiments, the clamping jaw 232 may be partially discontinuous. The portion A in FIG. 6 shows this discontinuity of the clamping jaw 232. A break portion 232a having a predetermined width is formed in a discontinuous portion of the clamping jaw 232. One or more break portions 232a may be selectively formed in the clamping jaw 232.

[0065] A plurality of feet 231 , which are each an element of the complementary locking portion provided to fix the gasket 23 to the mounting plate 22, are formed on the bottom surface of the gasket 23. A foot 231 at an edge of the gasket 23 enables the gasket 23 to be fixed to a frame base, and a foot 231 in an inner portion of the gasket 23 suppresses thermal distortion of the adsorbing surface 233 such that the substrate 1 is stably attached to the adsorbing surface 233. A diagonal break portion 234 of the adsorbing surface 233 absorbs horizontal distortion of opposite portions of the adsorbing surface 233, which face each other with the diagonal break portion 234 therebetween, thereby preventing plane distortion of the adsorbing surface 233.

[0066] FIG. 8 is a partial cross-sectional view taken at l-l of FIG 4. In detail, FIG. 8 shows an example of a state where the substrate 1 is mounted on the gasket 23 after the mounting plate 22 and the gasket 23 are coupled to the base plate 21. FIG. 9 is an enlarged view of a portion B in FIG. 8.

[0067] Referring to FIGS. 8 and 9, a foot 231 on the bottom surface of the gasket 23 is inserted into the slit 221 of the mounting plate 22. At this time, the foot 231 is forcedly inserted into the slit 221 (for example by interference fit), and therefore, the foot 231 is stably fixed in the slit 221 due to a compressive force.

[0068] The substrate 1 is inserted in the pocket of the gasket 23. The clamping jaw 232 of the gasket 23 is separated from the edge of the substrate 1 by a predetermined spacing "t" at a room temperature of about 15 °C to about 35 °C. A jaw supporter 222 (which may be part of the mounting plate 22) is disposed around an outer side of the clamping jaw 232. The jaw supporter 222 supports the clamping jaw 232 on a side of the clamping jaw 232 that is opposite the edge of the substrate 1. Accordingly, the substrate 1 is in close contact with the adsorbing surface 233 at the room temperature. At this time, the substrate 1 is attached to the adsorbing surface 233 by a VDW force. Accordingly, the substrate 1 may be fixed in a substrate fixture set (or the substrate clamping device 20) due to the VDW force throughout a procedure from loading of the substrate 1 to the substrate clamping device 20 (see FIG. 4) till the substrate fixture set reaches a load-lock chamber of a vacuum coating system. The substrate fixture set includes the substrate clamping device 20 and the substrate 1 mounted on the substrate clamping device 20.

[0069] When the substrate fixture set is loaded into a deposition apparatus, e.g., a meta-mode sputtering apparatus, a drum in a process chamber rotates at a high speed, and therefore, the VDW force may not be enough to fix the substrate 1 . However, when the temperature of the process chamber increases for, for example, plasma reaction in the process chamber or preheating, the substrate 1 and the substrate clamping device 20 holding the substrate 1 are heated. Accordingly, the gasket 23 is expanded, and therefore, the clamping jaw 232 is also expanded. Also, however, the expansion of the clamping jaw 232 is limited by the jaw supporter 222, causing the clamping jaw 232 to expand toward the substrate 1. As a result, the clamping jaw 232 presses the edge of the substrate 1 , thereby fixing the substrate 1.

[0070] Here, the coefficient of thermal expansion of the gasket 23 is much higher than the coefficients of thermal expansion of the mounting plate 22 and the substrate 1 . Accordingly, when the clamping jaw 232 of the gasket 23 is thermally expanded in the process chamber at an appropriate temperature (based on the material from which the gasket 23 is made), the expansion of the clamping jaw 232 is directed toward the substrate 1 by the jaw supporter 222 behind the clamping jaw 232. When the gasket 23 is thermally expanded, the clamping jaw 232 at the edge of the gasket 23 presses sides of the substrate 1. Consequently, in the elevated-temperature (relative to room temperature) environment of the chamber, the gasket 23 is thermally expanded, thereby holding the substrate 1.

[0071] The smoother the adsorbing surface 233 of the gasket 23, the higher the VDW force. Accordingly, a material of the gasket 23 desirably is selected, taking this characteristic into account. Since rubber products are usually manufactured using compression molding or injection molding, it is desirable to perform polishing and lapping on a portion of a mold, which corresponds to the adsorbing surface 233 of the gasket 23, when the mold is manufactured. The VDW force increases in proportion to the area of the adsorbing surface 233, but the gasket 23 may have an empty space through which the substrate 1 is pushed so that the substrate 1 may be easily detached from the gasket 23 of the substrate clamping device 20 after a coating process. In addition, since a material of the gasket 23, which is suitable for a high-temperature vacuum coating process, is usually expensive, design for reducing the volume of the gasket 23 may be desirable. [0072] In a substrate clamping device according to some embodiments, the spacing "t" between the clamping jaw 232 of the gasket 23 and the edge of the substrate 1 and a thickness W of the clamping jaw 232 in the room temperature are factors in effectively fixing the substrate 1. As described above, the spacing "t" between the clamping jaw 232 of the gasket 23 and the edge of the substrate 1 allows the substrate 1 to be easily inserted in the gasket 23. The greater the spacing "t", the substrate 1 may be more easily inserted in the gasket 23. However, a temperature at which a gasket wall, i.e. , the clamping jaw 232, is expanded to be in close contact with a side edge of the substrate 1 increases. In addition, since the amount of expansion of the clamping jaw 232 increases when the thickness W thereof increases, the greater the thickness W, the substrate 1 may be more securely fixed. However, since an area occupied by the gasket 23 increases when the thickness W of the clamping jaw 232 increases, the number of substrates 1 mounted on a single mounting plate 22 at a time during a coating process may be decreased. Accordingly, design conditions of the spacing "t" between the clamping jaw 232 and the substrate 1 and the thickness W of the clamping jaw 232 may be properly decided, taking account of coefficients of thermal expansion of the gasket 23, the mounting plate 22, and the substrate 1 , such that the substrate 1 may be easily inserted in the gasket 23 and the clamping jaw 232 may become in close contact with the side edge of the substrate 1 at as low temperature as possible. Also, to reduce cost of the gasket 23 while providing a suitable dimension W for a desired amount of thermal expansion, the clamping jaw 232 may be discontinuously disposed around the perimeter of the substrate 1 ; for example, the clamping jaw 232 may include many discontinuous portions 232a. When the substrate clamping device 20 is used for meta- mode sputtering, the substrate clamping device 20 may be designed such that the spacing "t" between the clamping jaw 232 and the substrate 1 is about zero at a temperature of about 50 °C to about 100 °C, which is a little higher than the room temperature.

[0073] A material suitable for a gasket may be selected, taking account one or more of the following desirable features: 1 ) a low outgassing rate suitable for a normal vacuum coating process and a high heat resistance against a high temperature of 100 °C or more; 2) a high coefficient of thermal expansion for secure fixation of a substrate; and 3) chemical resistance against a strong acid solution and a strong alkaline solution.

[0074] Meanwhile, to repeatedly use a substrate clamping device including a gasket, a coating material attached to the substrate clamping device may be removed through periodic cleaning, e.g., physical cleaning such as sandblasting or chemical cleaning using an etchant. When there is a risk that the gasket may be damaged by the physical cleaning, the chemical cleaning may be used.

[0075] Perflouroelastomer (FFKM) may be a gasket material which meets the desirable features described above. Commercialized FFKM products usually have a very low outgassing rate even at a high temperature of 200 °C or more, and a high chemical resistance and particularly have a coefficient of thermal expansion of 300 /m °C or more (wherein /M is micrometers or microns).

[0076] FIG. 10 is a diagram of circular cover glass (or a substrate) used in a smartwatch or the like. FIG. 11 is a perspective view of a top surface of a gasket corresponding to the circular cover glass. FIG. 12 is a perspective view of a bottom surface of the gasket. FIG. 13 is a partial cross-sectional view of a substrate clamping device, on which a circular gasket is mounted, according to some embodiments.

[0077] Referring to FIGS. 10 through 13, circular cover glass 2 has a shape of a circular plate. A decoration layer 2a displaying a particular pattern or information may be provided along a circumference of an inner surface (or a bottom surface) of the circular cover glass 2. A gasket 230 corresponding to the circular cover glass 2 has a circular shape to correspond to the shape of the circular cover glass 2, as shown in FIG. 1 1 . The gasket 230 includes an adsorbing surface 233 and a clamping jaw 232. A recess 235 is provided around the adsorbing surface 233 to protect the decoration layer 2a from touching the gasket 230. A plurality of feet 231 , which are each an element of the complementary locking portion, are formed on a bottom surface of the gasket 230, as described above. Break portions 234 are arranged in the adsorbing surface 233 at a predetermined angular interval. The break portions 234 absorb horizontal distortion of the adsorbing surface 233, thereby preventing plane distortion of the adsorbing surface 233. [0078] A mounting plate, on which the gasket 230 is mounted, may be designed to correspond to the circular shape of the gasket 230.

[0079] As described above, according to the embodiments, a substrate clamping device does not need to use an existing double-sided adhesive tape, e.g., Kapton tape, thereby allowing a substrate to be easily fixed and detached. In addition, uneven coating, which may occur when a gripper is used, and residues of foreign substances, which may occur when a tape is used, may be eliminated, so that a coating with high-quality optical characteristics may be formed. Furthermore, since a gasket is in gas-tightly contact with the edge of the substrate when holding the substrate, an unnecessary coating is prevented from being formed on a back side of the substrate during deposition, so that quality deterioration of the substrate due to back-coating may be prevented.

[0080] It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within an embodiment should typically be considered as available for other similar features or aspects in other embodiments.

[0081] While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A substrate clamping device comprising:

a gasket configured to hold a substrate and comprising an adsorbing surface, to which the substrate can be attached, and a clamping jaw around at least portion of the adsorbing surface, the clamping jaw being a dam type and capable of fixing the substrate to the gasket through thermal expansion; and

a jaw supporter adjacent to the clamping jaw and configured to support the clamping jaw to direct the thermal expansion of the clamping jaw toward the substrate.

2. The substrate clamping device of claim 1 , wherein the clamping jaw is integrally formed with the adsorbing surface.

3. The substrate clamping device of claim 1 or claim 2, wherein the gasket further comprises at least one well-type pocket configured to accommodate the substrate, the well-type pocket comprising the adsorbing surface on a bottom and the clamping jaw around the adsorbing surface, the clamping jaw being defined as a wall comprising a predetermined height for accommodating a side surface of the substrate.

4. The substrate clamping device of any one of claims 1 -3, further comprising a mounting plate comprising a gasket mount on which the gasket is mounted, wherein the gasket mount is a well type and comprises the jaw supporter.

5. The substrate clamping device of claim 4, further comprising a complementary locking portion in a back surface of the gasket and a bottom surface of the gasket mount.

6. The substrate clamping device of claim 5, wherein the complementary locking portion comprises:

a protrusion-type complementary locking portion in the back surface of the gasket; and a well- or slit-type complementary locking portion in the bottom surface of the gasket mount, the well- or slit-type complementary locking portion being coupled to the protrusion-type complementary locking portion.

7. The substrate clamping device of claim 4, wherein an inner surface of the clamping jaw is configured to be separated from an edge of the substrate by a predetermined spacing at a room temperature, and when the clamping jaw is thermally expanded, a back portion of the clamping jaw is supported by the jaw supporter and a front portion thereof is configured to press a side surface of the substrate.

8. The substrate clamping device of any one of claims 1 -7, wherein the adsorbing surface comprises a break portion configured to absorb horizontal expansion of the adsorbing surface to prevent distortion of the adsorbing surface.

9. The substrate clamping device of any one of claims 1 -8, wherein the clamping jaw is discontinuously formed around the adsorbing surface.

10. The substrate clamping device of claim 4, further comprising a base plate on which the mounting plate is mounted.

1 1. The substrate clamping device of any one of claims 1 -10, wherein a recess is formed in the adsorbing surface, the recess corresponding to a decoration layer formed on the substrate.

12. A substrate coating device comprising:

a vacuum chamber, a sputter target and a plasma source disposed in the vacuum chamber;

a vacuum system connected to the vacuum chamber;

a rotary drum installed in the vacuum chamber; and

a substrate clamping device configured to mount a substrate on the rotary drum, wherein the substrate clamping device comprises: a gasket configured to hold the substrate and comprising an adsorbing surface, to which the substrate is attached, and a clamping jaw around at least a portion of the adsorbing surface, the clamping jaw being a dam type and fixing the substrate to the adsorbing surface through thermal expansion; and

a jaw supporter opposite the substrate with the clamping jaw between the jaw supporter and the substrate and configured to support the clamping jaw to direct the thermal expansion of the clamping jaw toward the substrate.

13. A method of clamping a substrate, the method comprising:

preparing a gasket capable of holding the substrate;

attaching the substrate to the gasket at a room temperature using a molecular force; and

increasing a temperature of the gasket to mechanically clamp the substrate.

14. The method of claim 13, wherein the gasket comprises:

an adsorbing surface to which the substrate is attached; and

a clamping jaw configured to mechanically clamp a side surface of the substrate when the temperature is increased, the clamping jaw protruding along an edge of the adsorbing surface and being a dam type.

15. The method of claim 14, wherein a side surface of the clamping jaw is separated from an edge of the substrate by a predetermined spacing in the attaching of the substrate.

16. The method of claim 15, wherein the clamping jaw is thermally expanded to contact and press the side surface of the substrate by increasing the temperature of the gasket.

17. The method of claim 16, further comprising fixing the gasket to a mounting plate before the increasing of the temperature of the gasket, wherein the mounting plate comprises a jaw supporter configured to support the clamping jaw at a side of the clamping jaw.

18. The method of claim 17, wherein the mounting plate is configured to hold a plurality of gaskets.

19. The method of claim 14, wherein the adsorbing surface comprises a break portion, and the molecular force is maintained when the adsorbing surface is thermally expanded in the increasing of the temperature of the gasket.