Electrostatic chuck, substrate processing apparatus, and manufacturing method of electrostatic chuck

Abstract

It provides a technology that can suppress damage to the supporting substrate. The electrostatic chuck has a support surface that supports a substrate. The support surface is configured such that a plurality of protrusions formed at the same height are arranged in a planar direction. The plurality of protrusions each have a polished portion, at least at the uppermost portion that contacts the substrate, that has been polished.

Description

Technology Field

[0001] The present disclosure relates to an electrostatic chuck, a substrate processing apparatus, and a method for manufacturing an electrostatic chuck. Background Technology

[0002] Patent Document 1 discloses an electrostatic chuck that supports a substrate inside a vacuum vessel (processing vessel). The chuck plate of this electrostatic chuck is composed of an elastic body made of a dielectric resin such as silicon. In addition, the upper surface of the chuck plate has a plurality of convex parts (protrusions) by performing embossing.

[0003] Alternatively, the substrate processing device may apply an electrostatic chuck having a flat support surface without having multiple protrusions. Prior art literature

[0004] International Publication No. 2020 / 115952 The problem to be solved

[0005] The present disclosure provides a technology capable of suppressing damage to a supporting substrate. means of solving the problem

[0006] According to one aspect of the present disclosure, an electrostatic chuck is provided having a support surface that supports a substrate, wherein the support surface is configured such that a plurality of protrusions formed at the same height are arranged in a planar direction, and the plurality of protrusions have a polished portion having at least a polished portion at the top. Effects of the invention

[0007] According to one embodiment, damage to the supporting substrate can be suppressed. Brief explanation of the drawing

[0008] FIG. 1 is a side cross-sectional view illustrating a plasma processing apparatus according to one embodiment. FIG. 2 (A) is a side cross-sectional view showing an enlarged portion of an electrostatic chuck. FIG. 2 (B) is a plan view showing an enlarged support surface of one configuration example. FIG. 2 (C) is a plan view showing an enlarged support surface of another configuration example. FIG. 3 is a side cross-sectional view showing an enlarged view of a plurality of protrusions of an electrostatic chuck. Figure 4 is a flowchart showing the method of manufacturing an electrostatic chuck. FIGS. 5 (A) to FIGS. 5 (D) are first to fourth explanatory diagrams illustrating a method for manufacturing an electrostatic chuck. FIGS. 6 (A) and FIGS. 6 (B) are the fifth and sixth explanatory diagrams illustrating the manufacturing method of an electrostatic chuck. FIGS. 6 (C) is an enlarged drawing illustrating each protrusion being polished by the polishing step of the manufacturing method. FIG. 7 (A) is an enlarged cross-sectional view illustrating the state of support of a substrate by an electrostatic chuck according to the present embodiment. FIG. 7 (B) is an enlarged cross-sectional view illustrating the state of support of a substrate by an electrostatic chuck according to the first comparative example. FIG. 7 (C) is an enlarged cross-sectional view illustrating the state of support of a substrate by an electrostatic chuck according to the second comparative example. Figure 8 is a graph showing the simulation results of the electric field along a predetermined direction of the electrostatic chuck. Specific details for implementing the invention

[0009] Hereinafter, embodiments for implementing the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals are used for identical components, and redundant descriptions may be omitted.

[0010] FIG. 1 is a side cross-sectional view illustrating a plasma processing apparatus according to one embodiment. As shown in FIG. 1, an electrostatic chuck (67) according to one embodiment is applied to a plasma processing apparatus (100) for a flat panel display (FPD), which is an example of a substrate processing apparatus. Examples of FPDs include a liquid crystal display (LCD), an electroluminescence (EL), and a plasma display panel (PDP). Below, to facilitate understanding of the present invention, the configuration of this plasma processing apparatus (100) will be described first.

[0011] The plasma treatment device (100) is composed of an inductively coupled plasma (ICP) device that performs various substrate treatments on a flat panel display substrate (hereinafter simply referred to as substrate (G)) that is rectangular when viewed in a flat plane. Examples of substrate materials include glass or transparent synthetic resin. Examples of various substrate treatments include etching treatment and film formation treatment using the CVD (Chemical Vapor Deposition) method.

[0012] The planar dimensions of the substrate (G) processed by the plasma processing device (100) include, for example, a range of about 1500 mm × 1800 mm of the 6th generation to about 2800 mm × 3100 mm of the 10th generation. The thickness of the substrate (G) is, for example, about 0.3 mm to several mm.

[0013] The plasma processing device (100) illustrated in FIG. 1 comprises a rectangular box-shaped processing container (10) and a substrate loading platform (60) that is accommodated within the processing container (10) and on which a substrate (G) is loaded. Additionally, the plasma processing device (100) has a control unit (90) that controls various configurations of the device.

[0014] The processing container (10) includes a dielectric plate (11), an antenna container (12) installed on the vertical upper side of the dielectric plate (11), and a processing container body (13) installed on the vertical lower side of the dielectric plate (11), and the interior is divided into two upper and lower spaces by the dielectric plate (11). The antenna container (12) forms an antenna room together with the dielectric plate (11). The processing container body (13) forms a processing room (S) together with the dielectric plate (11).

[0015] Additionally, the processing container (10) has a rectangular frame-shaped support frame (14) inserted between the antenna container (12) and the processing container body (13). The support frame (14) has a portion that protrudes inwardly from the processing container (10), and supports the dielectric plate (11) by this portion. The processing container (10) is grounded through a ground wire (13c).

[0016] The antenna container (12) and the processing container body (13) are formed of a metal such as aluminum. The dielectric plate (11) is formed of ceramics such as alumina (Al2O3) or quartz.

[0017] On the side wall (13a) of the processing container body (13), an inlet / outlet port (13b) is provided to allow a substrate (G) to be brought in or out of the processing container body (13). The inlet / outlet port (13b) is opened and closed by a gate valve (20). When the gate valve (20) is opened, a conveying device not shown brings in or takes out a substrate (G) into or out of the processing container body (13) through the inlet / outlet port (13b).

[0018] Additionally, a plurality of exhaust ports (13d) connected to a gas exhaust unit (50) are provided at the bottom of the processing container body (13). The gas exhaust unit (50) is equipped with a plurality of gas exhaust pipes (51) connected to the plurality of exhaust ports (13d), an opening / closing valve (52) for opening and closing the exhaust passage of each gas exhaust pipe (51), and an exhaust device (53) to which each gas exhaust pipe (51) is connected. The exhaust device (53) has a vacuum pump such as a turbo molecular pump and vacuums the interior of the processing container body (13) during substrate processing.

[0019] A shower head (30) is provided on the lower surface of the dielectric plate (11). The shower head (30) also serves as a support beam for supporting the dielectric plate (11). The shower head (30) is formed from a metal such as aluminum. The surface of the shower head (30) may be subjected to anodizing treatment, etc. The shower head (30) has a flow path (31) extending in a horizontal direction and a plurality of gas discharge holes (32) communicating between the gas flow path (31) and a processing chamber (S) located vertically below the shower head (30).

[0020] A treatment gas supply unit (40) that supplies gas to a gas flow path (31) is connected to the shower head (30). The treatment gas supply unit (40) includes a gas supply pipe (41), an opening / closing valve (42) and a flow rate controller (43) provided at an intermediate position of the gas supply pipe (41), and a treatment gas supply source (44) provided at the end of the gas supply pipe (41). Additionally, when supplying multiple types of gas, the gas supply pipe (41) may be branched at an intermediate position, and each branch may be equipped with an opening / closing valve, a flow rate controller, and a treatment gas supply source. When performing plasma treatment, the plasma treatment device (100) supplies gas from the treatment gas supply source (44) to the gas flow path (31) of the shower head (30) through the gas supply pipe (41), and discharges gas to the treatment chamber (S) from each gas discharge hole (32).

[0021] The processing container (10) is equipped with a high-frequency antenna (15) inside the antenna container (12). The high-frequency antenna (15) is constructed by wiring an antenna wire (15a), formed of a conductive metal such as copper or aluminum, in a circular or spiral shape.

[0022] A feed member (16) extending upward from the antenna container (12) is connected to the terminal of the antenna line (15a). A feed line (17) is connected to the upper end of the feed member (16), and the feed line (17) is connected to a high-frequency power source (19) through a matching device (18) that performs impedance matching. For example, the plasma processing device (100) forms an induced electric field within the processing container body (13) by applying high-frequency power of 13.56 MHz from the high-frequency power source (19) to the high-frequency antenna (15). Due to this induced electric field, the processing gas supplied to the processing chamber (S) from the shower head (30) is plasmafied, and ions and radicals in the plasma are supplied to the substrate (G). The high-frequency power source (19) serves as a source for generating plasma, and the high-frequency power source (73) (an example of a power source) described later, which is connected to the substrate loading platform (60), serves as a bias power source that attracts the generated ions and imparts kinetic energy. In this way, while plasma is generated using inductive coupling in the ion source, the ion energy is controlled by connecting another power source, the bias power source, to the substrate loading platform (60), thereby allowing for independent control of plasma generation and ion energy, which increases the degree of freedom in substrate processing. Additionally, it is preferable that the frequency of the high-frequency power output from the high-frequency power source (19) be appropriately set within the range of 0.1 MHz to 500 MHz.

[0023] Meanwhile, a substrate loading platform (60) installed within a processing container (10) (processing container body (13)) has a substrate (61) that forms a temperature control area. Additionally, the substrate loading platform (60) has an electrostatic chuck (67) that directly supports a substrate (G) on the upper surface of the substrate (61).

[0024] The substrate (61) is formed as a rectangle when viewed in a planar view and has planar dimensions similar to those of the substrate (G) loaded on the substrate loading platform (60). For example, the length of the short side (first direction) of the substrate (61) is in the range of 1500 mm to 3000 mm, and the length of the long side (second direction) of the substrate (61) is in the range of 1800 mm to 3400 mm. In addition, the support surface (67s) of the electrostatic chuck (67) is also formed as a rectangle when viewed in a planar view according to the substrate (G), and for example, the dimension of the short side (first direction) is set to be 1400 mm or more, and the dimension of the long side (second direction) is set to be 1790 mm or more.

[0025] The substrate (61) is a metal plate having high thermal conductivity, formed, for example, of aluminum, aluminum alloy, stainless steel, etc., and is loaded onto a rectangular member (68) made of an insulating material. The rectangular member (68) is fixed to the bottom plate of the processing container body (13).

[0026] The substrate (61) has a temperature control medium channel (62) inside. Additionally, the substrate loading platform (60) may have various temperature control means, not limited to the temperature control medium channel (62). For example, the temperature control area of ​​the substrate (61) may be in a form having only a heater, or in a form having both the temperature control medium channel (62) and a heater.

[0027] At both ends of the temperature control medium flow path (62), a transfer pipe (64a) for supplying the temperature control medium and a return pipe (64b) for discharging the temperature control medium heated through the temperature control medium flow path (62) are connected. A transfer path (82) and a return path (83) are respectively connected to the transfer pipe (64a) and the return pipe (64b), and the transfer path (82) and the return path (83) are connected to a chiller (81). The chiller (81) controls the temperature or discharge flow rate of the temperature control medium and pressurizes the temperature control medium. A temperature control source (80) unique to the substrate (61) is formed by the chiller (81), the transfer path (82), and the return path (83).

[0028] The plasma processing device (100) may be configured to monitor the temperature of the substrate (G) by providing a temperature sensor, such as a thermocouple, not shown on the electrostatic chuck (67) or the substrate (61). When detection information from the temperature sensor is transmitted to the control unit (90), the control unit (90) controls the chiller (81) based on the detection information to adjust the temperature of the substrate loading platform (60) and the substrate (G). Additionally, the substrate (61) may have multiple temperature control areas set, and in this case, it is preferable to provide different temperature control medium channels, chillers, and temperature control sources corresponding to each temperature control area.

[0029] Additionally, the substrate loading platform (60) is provided with a heat transfer gas supply unit (not shown) that supplies a heat transfer gas, such as He gas, between the electrostatic chuck (67) and the substrate (G). The heat transfer gas supply unit supplies the heat transfer gas to the lower surface of the substrate (G) through a plurality of through holes (not shown) provided within the electrostatic chuck (67) and within the substrate (61). By doing so, the temperature of the substrate loading platform (60), which is subject to temperature control, is rapidly transferred to the substrate (G) through the heat transfer gas, thereby enabling temperature control of the substrate (G).

[0030] Additionally, the substrate loading platform (60) is equipped with a plurality of lift pins (not shown). The lift pins are raised along the vertical direction by means of a lifting mechanism not shown and protrude upward from the support surface (67s) of the electrostatic chuck (67) to receive and transfer the substrate (G) between the device and the conveyor.

[0031] Additionally, a stepped portion is formed by the outer circumference of the electrostatic chuck (67) and the substrate (61) and the upper surface of the rectangular member (68), and a square frame-shaped focus ring (69) is loaded on this stepped portion. In the installed state of the focus ring (69), the upper surface of the focus ring (69) is lower than the upper surface of the electrostatic chuck (67). The focus ring (69) is formed of ceramics such as alumina or quartz. When the substrate (G) is loaded on the support surface (67s) of the electrostatic chuck (67), the inner end of the upper surface of the focus ring (69) is covered by the outer circumference of the substrate (G).

[0032] A through hole (63a) is provided in the substrate (61), and a power supply member (70) is connected to the lower surface of the temperature control area of ​​the substrate (61) by passing through the through hole (63a). A power supply line (71) is connected to the lower end of the power supply member (70). The power supply line (71) is connected to a high-frequency power supply (73), which is a bias power supply, through a matching device (72) that performs impedance matching. That is, the temperature control area constituting the substrate (61) is electrically connected to the high-frequency power supply (73). The plasma processing device (100) can attract ions generated by the high-frequency power supply (19) to the substrate (G) by applying high-frequency power of, for example, 13.56 MHz from the high-frequency power supply (73) to the substrate loading platform (60). In addition, a power supply member (70) may be connected to the lower surface of the substrate (61), and high-frequency power may be applied to the substrate (61).

[0033] The electrostatic chuck (67) of the substrate loading stand (60) includes a dielectric (671) and an electrode (672) embedded inside the dielectric (671). The electrode (672) is connected to a DC power source (75) through a power supply line (74). The control unit (90) applies a DC voltage from the DC power source (75) to the electrode (672) by turning on a switch not shown provided on the power supply line (74), thereby generating an electrostatic force (Coulomb force) in the dielectric (671). Due to this electrostatic force, the substrate (G) is electrostatically adsorbed to the support surface (67s) of the electrostatic chuck (67).

[0034] Hereinafter, the configuration of this electrostatic chuck (67) will be described in more detail. FIG. 2 (A) is a side cross-sectional view showing an enlarged portion of the electrostatic chuck (67). FIG. 2 (B) is a plan view showing an enlarged portion of the support surface (67s) of one configuration example. FIG. 2 (C) is a plan view showing an enlarged portion of the support surface (67s) of another configuration example. In addition, FIG. 2 (A), and FIG. 3, FIG. 5 to FIG. 7 described later, show the vertical dimensions with respect to the horizontal dimensions in order to facilitate understanding of the invention.

[0035] As illustrated in (A) of FIG. 2, the electrostatic chuck (67) is formed into a three-layer structure having a lower layer (673), an intermediate layer (674), and an upper layer (675) by spraying a plurality of materials onto a base material and stacking them. For the base material, a plate made of, for example, aluminum, aluminum alloy, stainless steel, etc. may be used. As the base material, the above-mentioned substrate (61) may be used, or a material different from the substrate (61) may be used.

[0036] The lower layer (673) and the upper layer (675) constitute the dielectric (671) of the electrostatic chuck (67). As materials forming the lower layer (673) and the upper layer (675), insulating materials such as alumina (Al2O3) can be used, for example. Meanwhile, the intermediate layer (674) constitutes the electrode (672) of the electrostatic chuck (67). As materials forming the intermediate layer (674), conductive materials such as tungsten (W) can be used, for example. That is, the three-layer structure is manufactured by first spraying alumina onto a base material to form the lower layer (673), then spraying tungsten onto the lower layer (673) to form the intermediate layer (674), and finally spraying alumina onto the intermediate layer (674) again to form the upper layer (675).

[0037] In addition, on the surface (reference surface (675a)) of the upper layer (675) of the electrostatic chuck (67) according to the present embodiment, a plurality of protrusions (676) are provided by performing embossing during the manufacture of the electrostatic chuck (67). In particular, in the present embodiment, the plurality of protrusions (676) are formed as micro-embossed with a maximum width of 0.3 mm or less. Each of the plurality of protrusions (676) is made of the same material (alumina, etc.) as the upper layer (675) and is integrally molded into the upper layer (675). Each protrusion (676) protrudes at the same height in the vertical upward direction from the reference surface (675a). A gap (676c) of a certain width is interposed between two adjacent protrusions (676).

[0038] Each protrusion (676), when viewed in a planar view as shown in (B) of FIG. 2, forms a row of protrusions arranged at equal intervals along a first direction parallel to the short side of the electrostatic chuck (67), and also shows a matrix shape in which a row of protrusions is arranged at equal intervals along a second direction parallel to the long side of the electrostatic chuck (67). Additionally, as shown in (C) of FIG. 2, each protrusion (676) of two adjacent rows of protrusions may be formed in an offset manner in a zigzag shape.

[0039] Each protrusion (676) is formed in a circular shape when viewed in a planar view. However, the shape of each protrusion (676) when viewed in a planar view is not limited to a circular shape, but may be formed in an elliptical shape, a polygonal shape including a square, etc. For example, a plurality of square protrusions (676) may be arranged in a matrix shape, thereby forming a grid-like gap (676c) between each protrusion (676).

[0040] FIG. 3 is a side cross-sectional view showing an enlarged view of a plurality of protrusions (676) of an electrostatic chuck (67). As shown in FIG. 3, each protrusion (676) has a base (677) connected to a reference surface (675a) of an upper layer (675) and a head portion (678) connected to the upper part of the base (677). The head portion (678) of each protrusion (676) forms a support surface (67s) that supports a substrate (G).

[0041] The base (677) is formed in a conical shape that gradually decreases in diameter toward the vertical upward direction from the reference plane (675a). Additionally, the base (677) may be formed in a columnar shape having a constant outer diameter along the vertical direction.

[0042] The head portion (678) is smoothly continuous with respect to the outer circumference of the base (677) and is formed as a hemispherical curved surface. The radius of curvature of the head portion (678) is set to be smaller than the radius of the base (677). The top portion (678a) located at the uppermost vertical position of the head portion (678) becomes the part that directly contacts the substrate (G).

[0043] In the head portion (678), at least the top portion (678a) is made of a polished portion (679) that is mirror-polished by the polishing process of the manufacturing method of the electrostatic chuck (67) described later. The polished portion (679) is not limited to the top portion (678a) but may be continuous with the curved peripheral portion (678b) of the head portion (678) surrounding the top portion (678a). For example, the surface roughness Ra of the polished portion (679) may be set in the range of 0.1 to 0.5. Meanwhile, the outer surface of the base (677) does not need to be provided with the polished portion (679), and the surface roughness Ra of this outer surface is set in the range of 0.5 to 1.0. By forming a smooth curved surface by the polishing part (679), each protrusion (676) can be supported without damaging the opposing surface (bottom) of the substrate (G).

[0044] Alternatively, the top portion (678a) of the head portion (678) may be formed flat along the horizontal direction. In this case, the top portion (678a) and the curved peripheral portion (678b) may be continuous through an R-shaped boundary formed by the polishing portion (679).

[0045] The height H of each protrusion (676) relative to the reference plane (675a) is preferably set appropriately considering the durability of each protrusion (676) or the flowability of the heat transfer gas flowing between the electrostatic chuck (67) and the substrate (G), and, for example, can be set in the range of 0.01 mm to 0.05 mm. In this embodiment, the height H of each protrusion (676) is set to 0.02 mm (= 20 μm).

[0046] Additionally, the spacing D between the plurality of protrusions (676) is preferably set to a range of 0.2 mm to 0.5 mm. In this embodiment, the spacing D between the plurality of protrusions (676) is set to 0.35 mm (= 350 μm). Also, in this specification, the spacing D between the plurality of protrusions (676) refers to the distance between the top portions (678a) of adjacent protrusions (676).

[0047] And, it is preferable that the diameter φ (maximum width) of each protrusion (676) be appropriately set according to the spacing D between the plurality of protrusions (676) described later. For example, the diameter φ of each protrusion (676) may be set at a ratio of 0.2 to 0.7 times with respect to the spacing D between the plurality of protrusions (676). By adopting this ratio, the electrostatic chuck (67) can stably support the substrate (G) by each protrusion (676) while allowing the heat transfer gas to flow smoothly through the gap (676c). In addition, in this embodiment, the diameter φ of the protrusion (676) corresponds to the diameter of the base (677) at the location in contact with the reference surface (675a). Accordingly, the diameter of the head portion (678) of the protrusion (676) is smaller than the diameter of the base (677). In addition, if each protrusion (676) is square, the maximum width of each protrusion (676) is the length of the diagonal.

[0048] However, if the diameter φ of each protrusion (676) is less than 0.1 mm, there is a concern regarding the difficulty of manufacturing the protrusion (676) and the decrease in the durability of the protrusion (676). For this reason, the lower limit of the diameter φ of each protrusion (676) should be 0.1 mm. In addition, if the diameter φ of each protrusion (676) exceeds 0.3 mm, the number of places where the protrusion (676) approaches the substrate (G) increases, and there is a possibility that non-uniformity in the electric field described later may occur. Therefore, it is more preferable to set the diameter φ of each protrusion (676) to a range of 0.1 mm to 0.3 mm. In this embodiment, the diameter φ of the protrusion (676) is set to 0.175 mm (= 175 μm).

[0049] The electrostatic chuck (67) has a 1 mm design by adopting the design of each of the above protrusions (676). 2 By increasing the number of protrusions (676) per unit, a sufficient gap (676c) (gap D) can be secured. 1 mm 2 In each unit, a plurality of protrusions (676) come into contact with the substrate (G), thereby making it possible to stably support the substrate (G).

[0050] More specifically, the electrostatic chuck (67), when viewed as a plane of the support surface (67s), is 1 mm of the support surface (67s). 2 It is preferable to set the area occupancy of the multiple protrusions (676) occupying the unit to a range of 3% to 40%. If the occupancy is less than 3%, the support of the substrate (G) becomes unstable, whereas if the occupancy exceeds 40%, there is a possibility that temperature non-uniformity may occur during the deposition of reaction by-products. In addition, the area of ​​the multiple protrusions (676) is 1 mm of the support surface (67s). 2 In terms of units, it refers to the sum of the areas of the bases (677) at locations connected to the reference plane (675a).

[0051] Since the shape of each protrusion (676) and the spacing D between each protrusion (676) are small, it is difficult to perform embossing on the electrostatic chuck (67) according to the present embodiment by a conventional manufacturing method. A conventional manufacturing method is a method in which a metal mask plate (not shown) having a plurality of through holes is placed on the upper layer (675) of the electrostatic chuck (67), and alumina, which is the material of the protrusion (676), is sprayed by thermal spraying while the mask plate is stacked. Therefore, the electrostatic chuck (67) according to the present embodiment performs embossing by a manufacturing method different from the conventional method to form each protrusion (676).

[0052] Next, a method for manufacturing an electrostatic chuck (67) having a protrusion (676) will be described with reference to FIGS. 4 to 6. FIG. 4 is a flowchart illustrating a method for manufacturing an electrostatic chuck (67). FIGS. 5 (A) to FIGS. 5 (D) are first to fourth explanatory diagrams illustrating a method for manufacturing an electrostatic chuck (67). FIGS. 6 (A) and FIGS. 6 (B) are fifth and sixth explanatory diagrams illustrating a method for manufacturing an electrostatic chuck (67). FIG. 6 (C) is an enlarged view illustrating each protrusion (676) being polished by a polishing step of the manufacturing method.

[0053] As shown in FIG. 4, in the method for manufacturing an electrostatic chuck (67), a three-layer structure forming process (S1), a flat grinding process (S2), a screen printing process (S3), and a blast processing process (S4) are carried out in this order.

[0054] The three-layer structure forming process (S1) involves laminating a three-layer structure, consisting of a lower layer (673), a middle layer (674), and an upper layer (675) of the electrostatic chuck (67), onto a base material (e.g., a substrate (61)) as described above. Additionally, in the three-layer structure forming process (S1), the thickness of the upper layer (675) is formed to be thicker than the thickness of the lower layer (673) so that the upper layer (675) can be cut later to create each protrusion (676).

[0055] The surface grinding machine processing process (S2) processes the surface of the upper layer (675) of the precursor P1 formed by the three-layer structure forming process (S1) into a flat shape. In this surface grinding machine processing process (S2), a surface grinding machine (200) as shown in (A) of FIG. 5 is used. For example, the surface grinding machine (200) has a grinding wheel (201) that moves horizontally while rotating along the surface of the precursor P1, and a support (not shown) that supports the precursor P1. The surface grinding machine (200) grinds the upper layer (675) under the operation of the grinding wheel (201) to make the surface of the upper layer (675) into a flat shape.

[0056] The screen printing process (S3) of FIG. 4 forms a mask by performing screen printing on a precursor P2 formed by a flat grinding machine process (S2). Specifically, in the screen printing process (S3), a screen printing step (S31) for applying ink (I) and a curing step (S32) for curing the applied ink (I) are performed in sequence.

[0057] In the screen printing step (S31), a screen printing device (300) as shown in (B) of FIG. 5 is used. The screen printing device (300) has a square frame-shaped frame (301), a plate (302) set inside the frame (301), and a support (not shown) that supports a precursor P2 in the vertical direction below the plate (302). In the plate (302), a plurality of holes (302h) are formed corresponding to the planar shape of each protrusion (676) of the electrostatic chuck (67) and the spacing D between each protrusion (676). That is, the diameter of each hole (302h) is set to be approximately the same as the diameter φ of each protrusion (676), and the spacing between each hole (302h) is set to be approximately the same as the spacing D between each protrusion (676).

[0058] In the screen printing step (S31), before printing, ink (I) applied to the mask (M) is filled onto the upper surface of the plate (302). It is preferable that the ink (I) be a material that can be cured by irradiation with ultraviolet (UV) light and is also resistant to removal in the blast processing process (S4) described later. For example, resin materials such as polyester, polyester acrylate, epoxy acrylate, urethane acrylate, and trimethylolpropane triacrylate can be used as the material for the ink (I).

[0059] As illustrated in (C) of FIG. 5, in screen printing, the screen printing device (300) slides the squeegee (303) along the upper surface of the plate (302) while pressing ink (I) onto the plate (302) by means of the squeegee (303). As a result, the plate (302) comes into contact with the lower precursor P2, and the ink (I) is applied to the precursor P2 in a dot shape through each hole (302h) of the plate (302).

[0060] After that, in the curing step (S32) of FIG. 4, the precursor P2 is removed from the screen printing device (300) and the ink (I) applied in a dot shape is cured. As shown in (D) of FIG. 5, in this curing step (S32), an ultraviolet irradiation device (310) is placed above the precursor P2 having the ink (I), and ultraviolet (UV) rays are irradiated from the ultraviolet irradiation device. By doing so, the ink (I) is cured, and a precursor P3 having a plurality of dot-shaped masks (M) on a flat surface is formed. Additionally, the masks (M) can be formed by inkjet printing, but screen printing is preferred for printing the ink in a dot shape in a micro size without insufficient adhesion.

[0061] And, the blast processing process (S4) of FIG. 4 forms each protrusion (676) by performing blast processing on a precursor P3 having a plurality of point-shaped masks (M). Specifically, in the blast processing process, an embossing forming step (S41) in which a blast material is sprayed to engrave the precursor P3 other than the mask (M), and a polishing step (S42) in which each protrusion (676) having the mask (M) are polished are performed in sequence.

[0062] In the embossing formation step, a blast device (400) as shown in (A) of FIG. 6 is used. The blast device (400) has a nozzle (401) that moves while spraying blast material and a support (not shown) that supports the precursor P3. The blast material used is a material capable of grinding the upper layer (675) (alumina) while suppressing the grinding of the hardened mask (M). For example, the blast material may be granular glass beads, alumina, silicon carbide (SiC), zirconia (ZrO2), etc.

[0063] The blast device (400) engraves the entire upper layer (675) surrounding the mask (M) by spraying blast material while moving the nozzle (401) and the precursor P3 relative to each other. For example, the blast device (400) can form gaps (466c) of the same depth in the upper layer (675) by making the unit operation time of spraying blast material uniform on the surface of the upper layer (675). As a result, a precursor P4 having each protrusion (676) with the mask (M) remaining on the head part (678) is formed. By forming the emboss by excavating with the blast in this way, the height of the top part (678a) is aligned more than with the conventional method of thermal spraying, and the emboss becomes difficult to detach.

[0064] In the polishing step (S42), the polishing part (679) is formed by removing the mask (M) on each protrusion (676) and performing buff polishing on each protrusion (676). For example, in the polishing step (S42), a polishing device (410) as shown in (B) of FIG. 6 is used. The polishing device (410) has a polishing body (411) that moves while rotating the buff (412) and a support (not shown) that supports the precursor P4. The buff (412) is used to be capable of removing the mask (M) and polishing each protrusion (676). Examples of this buff (412) include fabric materials such as linen or cotton, or sponge materials such as nylon. The polishing device (410) may first use a dedicated polishing body (411) for removing the mask (M), and then use another polishing body (411) for polishing so that the head portion (678) of each protrusion (676) becomes hemispherical.

[0065] As shown in Fig. 6 (C), the upper end of each protrusion (676), which had a flat shape due to the flat grinding process (S2), is polished into a hemispherical shape by the buff polishing above. That is, each protrusion (676) in this embodiment is polished to a mirror finish with the entire head part (678) (top part (678a) and curved edge part (678b)) under the rotation of the buff (412), and becomes a state having a polished part (679).

[0066] The support surface (67s) of the electrostatic chuck (67) manufactured by the above manufacturing method can support the weight of the substrate (G) by distributing it through a plurality of embossed protrusions (676) of the same height. In particular, by having a polishing part (679) on the top part (678a) of each protrusion (676) that is in direct contact with the substrate (G), each protrusion (676) can support the substrate (G) while suppressing damage to the substrate (G).

[0067] Next, the effect of supporting a substrate (G) by an electrostatic chuck (67) having a plurality of protrusions (676) will be explained with reference to FIGS. 7 and 8. FIG. 7 (A) is an enlarged cross-sectional view illustrating the state of support of a substrate (G) by an electrostatic chuck (67) according to the present embodiment. FIG. 7 (B) is an enlarged cross-sectional view illustrating the state of support of a substrate (G) by an electrostatic chuck (C1) according to the first comparative example. FIG. 7 (C) is an enlarged cross-sectional view illustrating the state of support of a substrate (G) by an electrostatic chuck (C2) according to the second comparative example.

[0068] The electrostatic chuck (C1) according to the first comparative example has a support surface (67s) formed in a roughly flat shape by thermal spraying (or grinding) without performing embossing. However, as shown in (B) of FIG. 7, even though the support surface (67s) is flat, when viewed enlarged in millimeters, it is in a state where a plurality of tooth-shaped protrusions are formed. That is, the electrostatic chuck (C1) supports the substrate (G) on the plurality of tooth-shaped convex parts constituting the support surface (67s).

[0069] When a deposition (DP) occurs in conjunction with plasma processing of the plasma processing device (100), the deposition (DP) accumulates at multiple sawtooth-shaped protrusions on the support surface (67s) of the electrostatic chuck (C1). As the deposition (DP) accumulates in this manner, a portion of the electrostatic chuck (C1) that comes into frequent contact with the substrate (G) through the deposition (DP) and a portion that does not come into contact with the substrate (G) due to the absence of the deposition (DP) are created. In other words, the portion that comes into frequent contact with the substrate (G) and the portion that does not come into contact with the substrate (G) cause uneven heat transfer when the electrostatic chuck (C1) is temperature-controlled. Furthermore, as unevenness occurs in the temperature distribution within the surface of the substrate (G), unevenness also occurs in the substrate processing, leading to unevenness in the display of the flat panel display.

[0070] Meanwhile, the electrostatic chuck (C2) according to the second comparative example has a supporting surface (67s) formed by performing embossing. However, the embossing according to the second comparative example involves forming protrusions (676) on the upper layer (675) by the aforementioned thermal spraying. Therefore, as shown in (C) of FIG. 7, when viewed enlarged in mm units, a plurality of saw-like protrusions are formed on the head portion of each protrusion (676). Accordingly, the electrostatic chuck (C2) also supports the substrate (G) on the multiple saw-like convex portions of each protrusion (676).

[0071] When deposition (DP) occurs in conjunction with plasma processing of the plasma processing device (100), the deposition (DP) accumulates in the gaps (676c) between the multiple protrusions (676) on the support surface (67s) of the electrostatic chuck (C2). Because of this, the portion of the electrostatic chuck (C2) that comes into contact with the substrate (G) through the deposition (DP) is suppressed. However, for each protrusion (676), a portion that comes into contact with the substrate (G) through the deposition (DP) occurs, and there is a slight difference in the heat transfer characteristics of each protrusion (676) between the support state when there is no deposition (DP) and the support state when there is deposition (DP).

[0072] In contrast, the support surface (67s) of the electrostatic chuck (67) according to the present embodiment has a micro-emboss (multiple protrusions (676)) formed by the manufacturing method described above. Furthermore, as shown in (A) of FIG. 7, when viewed enlarged in mm units, each protrusion (676) supports the substrate (G) at the top part (678a) (polished part (679)) which is mirror-polished.

[0073] When deposition (DP) occurs in conjunction with plasma processing of the plasma processing device (100), on the support surface (67s) of the electrostatic chuck (67), deposition (DP) accumulates in the gap (676c) between the multiple protrusions (676), and hardly accumulates on the top part (678a) of each protrusion (676). As a result, the part of the electrostatic chuck (67) that comes into contact with the substrate (G) through the deposition (DP) is suppressed, and changes in heat transfer characteristics due to the deposition of deposition (DP) on each protrusion (676) are suppressed as much as possible. Therefore, it can be said that the electrostatic chuck (67) can continuously maintain a uniform temperature distribution within the surface of the substrate (G) even when the substrate processing is repeated multiple times, and it becomes possible to reduce non-uniformity in the substrate processing.

[0074] FIG. 8 is a graph showing the simulation results of an electric field along a predetermined direction of an electrostatic chuck (67, C2). The solid line in FIG. 8 represents the electric field when a substrate (G) is supported by the electrostatic chuck (67) according to the present embodiment, while the dotted line in FIG. 8 represents the electric field when a substrate (G) is supported by the electrostatic chuck (C2) according to the second comparative example. Furthermore, the electric field of the electrostatic chuck (67, C2) is an electric field generated by applying a predetermined high-frequency voltage to a substrate (61) from a high-frequency power source (73).

[0075] In the electrostatic chuck (C2) according to the second comparative example, a plurality of protrusions (676) are arranged at positions spaced apart by approximately 5 mm. This is because each protrusion (676) of the electrostatic chuck (C2) is formed by thermal spraying as described above. Therefore, the electric field of the electrostatic chuck (C2) is formed to have a plurality of convex shapes, as shown in FIG. 8. The location of each convex shape of the electric field coincides with the position where each protrusion (676) of the electrostatic chuck (C2) supports the substrate (G). In other words, in the electrostatic chuck (C2), it can be considered that there is non-uniformity (large variation in the electric field) in the electric field applied to the substrate (G) due to each protrusion (676).

[0076] In contrast, in the electrostatic chuck (67) according to the present embodiment, the spacing between the plurality of protrusions (676) is 0.2 to 0.5 mm, and also 1 mm of the support surface (67s). 2 The area of ​​the multiple protrusions (676) occupying the unit is in the range of 3% to 40%. That is, compared to the electrostatic chuck (C2) in the second comparative example, the electrostatic chuck (67) supports the substrate (G) by very small multiple protrusions (676), so it can be said that the substrate (G) is supported by a substantially flat support surface (67s).

[0077] Therefore, the electric field of the electrostatic chuck (67) is formed to change into a roughly flat shape. In other words, the electrostatic chuck (67) can support the substrate (G) in a state where the distribution of the electric field within the plane of the substrate (G) is roughly uniform (the change in the electric field is small). By doing so, the electrostatic chuck (67) can further reduce the non-uniformity of the substrate processing on the supported substrate (G). Furthermore, non-uniformity of the substrate processing refers to a change in the amount of processing on the substrate (G), depending on the content of the substrate processing. For example, if the substrate processing is etching, it refers to a change in the uniformity of the etching rate within the plane, or if the substrate processing is film deposition, it refers to a change in the uniformity of the film thickness within the plane. In other words, the electrostatic chuck (67) according to the present embodiment can greatly increase the uniformity of the substrate processing within the plane by means of each protrusion (676) that has been micro-embossed.

[0078] The technical concept and effects of the present disclosure described in the above embodiments are described below.

[0079] A first aspect of the present disclosure is an electrostatic chuck (67) having a support surface (67s) that supports a substrate (G), wherein the support surface (67s) is configured such that a plurality of protrusions (676) formed at the same height are arranged in a planar direction, and the plurality of protrusions (676) have a polished portion (679) that is polished at least at the top portion (678a).

[0080] According to the above, the electrostatic chuck (67) has a polishing portion (679) at least on the top portion (678a), thereby enabling stable support of the substrate (G) while suppressing damage to the substrate (G). Specifically, to verify the support state of the substrate (G), an experiment was conducted in which a substrate (G) adsorbed over a predetermined period of time by the electrostatic chuck (C2) according to the second comparative example and a substrate (G) adsorbed over the same period of time by the electrostatic chuck (67) according to the present embodiment were removed, and scratches were observed using a laser microscope. As a result of the experiment, the substrate (G) supported by the electrostatic chuck (C2) had multiple deep scratches. On the other hand, the substrate (G) supported by the electrostatic chuck (67) had almost no scratches, and the scratches themselves were shallow. Therefore, it can be considered that the electrostatic chuck (67) suppresses scratches on the substrate (G) by the polishing portion (679).

[0081] Additionally, the surface roughness of the polishing portion (679) is in the range of 0.1 to 0.5. Since each protrusion (676) has such surface roughness, the electrostatic chuck (67) can more reliably suppress scratches on the substrate (G).

[0082] Additionally, a plurality of protrusions (676) include a base (677) and a head portion (678) integrally molded on the upper part of the base (677), and the head portion (678) is formed in a hemispherical shape and has a polishing portion (679) on the top portion (678a) of the hemispherical shape. By this, the electrostatic chuck (67) can support the substrate (G) by point contact at the top portion (678a) of each protrusion (676), and furthermore, damage to the substrate (G) can be suppressed by the polishing portion (679).

[0083] Additionally, the polishing portion (679) is formed over the entire surface of the head portion (678). By doing so, the electrostatic chuck (67) can easily form the polishing portion (679) on the head portion (678) of each protrusion portion (676) by applying buff polishing.

[0084] In addition, the spacing between multiple adjacent protrusions (676) is in the range of 0.2 mm to 0.5 mm, and also, when viewed from the plane of the support surface (67s), 1 mm of the support surface (67s) 2 The area occupancy of the multiple protrusions (676) occupying the unit is in the range of 3% to 40%. Accordingly, the electrostatic chuck (67) can support the weight of the substrate (G) by distributing it through the numerous small protrusions (676), thereby further reducing damage to the substrate (G).

[0085] Additionally, the electrostatic chuck (67) supports a substrate for a flat panel display as a substrate (G), and the support surface (67s) is formed in a rectangular shape when viewed from the plane of the support surface (67s), with a first direction dimension of 1490 mm or more and a second direction dimension orthogonal to the first direction of 1790 mm or more. Accordingly, the electrostatic chuck (67) can support the substrate (G) by suppressing the occurrence of scratches on the substrate for a flat panel display having weight through the support surface (67s) which is composed of a plurality of protrusions (676).

[0086] In addition, a second aspect of the present disclosure is a substrate processing device (plasma processing device (100)) for a flat panel display, comprising a processing vessel (10) for performing substrate processing on a substrate (substrate (G)) for a flat panel display, and an electrostatic chuck (67) provided inside the processing vessel (10) and having a supporting surface (67s) for supporting the substrate for a flat panel display, wherein the supporting surface (67s) is configured such that a plurality of protrusions (676) formed at the same height are arranged in a planar direction, and the plurality of protrusions (676) have a polished portion (679) in which polishing is performed at least on the uppermost portion (678a). In this case as well, the substrate processing device can suppress damage to the substrate (G).

[0087] Additionally, a third aspect of the present disclosure is a method for manufacturing an electrostatic chuck (67) having a supporting surface (67s) that supports a substrate (G), wherein the supporting surface (67s) is configured such that a plurality of protrusions (676) formed at the same height are arranged in a planar direction, and a process of (A) flattening the surface of a precursor, (B) forming a plurality of dot-shaped masks (M) on the surface of the flattened precursor, and (C) forming a gap (676c) between the plurality of masks (M) by performing a blast process, and then removing the masks (M) are performed in this order to form a plurality of protrusions (676), and in the process of (C), a blast material is sprayed onto the precursor having the plurality of masks (M) to engrave it onto the precursor, and then the masks (M) are removed by polishing the surface of the precursor to form a polished portion (679) in which polishing is performed on at least the uppermost portion (678a) of the plurality of protrusions (676). In this case as well, the manufacturing method of the electrostatic chuck (67) can suppress damage to the substrate (G).

[0088] In addition, in process (B), a plurality of dot-shaped inks (I) are applied to the surface of a precursor by screen printing, and then a plurality of masks (M) are formed by curing the plurality of inks (I) by irradiating them with ultraviolet light.

[0089] In addition, the surface roughness of the polishing part (679) is in the range of 0.1 to 0.5.

[0090] Additionally, a plurality of protrusions (676) include a base (677) and a head portion (678) integrally molded on the upper part of the base (677), and the head portion (678) is formed in a hemispherical shape and has a polishing portion (679) on the top portion (678a) of the hemispherical shape.

[0091] Additionally, the polishing portion (679) is formed over the entire surface of the head portion (678).

[0092] In addition, the spacing between multiple adjacent protrusions (676) is in the range of 0.2 mm to 0.5 mm, and also, when viewed from the plane of the support surface (67s), 1 mm of the support surface (67s) 2 The area of ​​the multiple protrusions (676) occupying the unit is in the range of 3% to 40%.

[0093] Additionally, the electrostatic chuck (67) supports a substrate for a flat panel display as a substrate (G), and the support surface (67s) is formed in a rectangular shape when viewed from the plane of the support surface (67s), the dimension in the first direction is 1490 mm or more, and the dimension in the second direction orthogonal to the first direction is 1790 mm or more.

[0094] The electrostatic chuck (67), plasma processing device (100), and method of manufacturing the electrostatic chuck (67) according to the embodiments disclosed herein are illustrative in all respects and are not restrictive. The embodiments may be modified and improved in various forms without departing from the appended claims and their common knowledge. The details described in the plurality of embodiments may also take other configurations and may be combined within a non-contradictory scope.

[0095] The electrostatic chuck (67) of the present disclosure is applicable to any type of device including an Atomic Layer Deposition (ALD) device, Capacitively Coupled Plasma (CCP), Inductively Coupled Plasma (ICP), Radial Line Slot Antenna (RLSA), Electron Cyclotron Resonance Plasma (ECR), and Helicon Wave Plasma (HWP).

Claims

Claim 1 An electrostatic chuck having a support surface that supports a substrate, wherein the support surface is configured such that a plurality of protrusions formed at the same height are arranged in a planar direction, and the plurality of protrusions each include a base and a head portion integrally molded on the upper part of the base, wherein the head portion is formed in a hemispherical shape and has a polishing portion at the top of the hemispherical shape, wherein the spacing between the plurality of protrusions adjacent to each other is in the range of 0.2 mm to 0.5 mm and the height of each protrusion is in the range of 0.01 mm to 0.05 mm. Claim 2 In paragraph 1, the above-mentioned base is an electrostatic chuck that is conical or columnar in shape. Claim 3 In claim 1, the topmost portion is an electrostatic chuck formed flat along the horizontal direction. Claim 4 In claim 1, the polishing portion is an electrostatic chuck that is continuous with the periphery of the curved surface in addition to the top portion. Claim 5 An electrostatic chuck according to claim 1, wherein the surface roughness Ra of the polishing portion is in the range of 0.1 to 0.

5. Claim 6 The electrostatic chuck according to claim 1, wherein the plurality of protrusions form a row of protrusions arranged along a direction parallel to the short side or long side of the electrostatic chuck, and each protrusion of the adjacent row of protrusions is formed in an offset manner in a zigzag shape. Claim 7 An electrostatic chuck according to claim 1, wherein the shape of each projection viewed in a planar view is formed as an elliptical shape or a polygonal shape.

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