Electrostatic chuck

Abstract

To provide an electrostatic chuck capable of suppressing an influence of a position deviation of a cooling flow path.SOLUTION: An electrostatic chuck comprises: a ceramic dielectric substrate; and a base plate supporting the ceramic dielectric substrate and including an upper surface on the ceramic dielectric substrate side and a lower surface on the side opposite to the upper surface. The base plate contains a communication path which is provided between the upper surface and the lower surface, and in which a coolant can be passed. The communication path contains a first flow path part that includes a pair of side surfaces along a first direction along a flow of the coolant. One side surface of the pair of side surfaces includes: a plurality of convex parts in a convex shape to a second direction directed that is a second direction vertical to a first direction in the case of the view of a lamination direction of the base plate and the ceramic dielectric substrate in one side surface of the pair of side surfaces to one side surface from the other side surface of the pair of side surfaces; and a plurality of concave parts which forms a convex shape to a direction opposite to a second direction. In the electrostatic chuck, the plurality of convex parts and the plurality of concave parts are alternately arranged.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] Aspects of the present invention generally relate to electrostatic chucks. [Background technology]

[0002] Electrostatic chucks are known on which processing objects such as semiconductor wafers and glass substrates are placed. Electrostatic chucks are used as a means for attracting and holding processing objects in plasma processing chambers of semiconductor manufacturing equipment that performs processes such as etching, CVD (Chemical Vapor Deposition), sputtering, ion implantation, and ashing. Electrostatic chucks apply electrostatic attraction power to built-in electrodes, for example, to attract substrates such as silicon wafers by electrostatic force.

[0003] The electrostatic chuck includes a ceramic dielectric substrate having a mounting surface on which a workpiece is placed, and a base plate supporting the ceramic dielectric substrate, the base plate sometimes being provided with a coolant flow path for cooling the workpiece. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-115933 [Patent Document 2] Japanese Patent Application Publication No. 2020-161597 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-208565 Summary of the Invention [Problem to be solved by the invention]

[0005] In the manufacturing process of an electrostatic chuck, the position of the coolant flow channel may deviate from the design. For example, manufacturing variations occur in the position of the coolant flow channel relative to at least a portion of a substrate on which an object to be processed is placed. If the position of the coolant flow channel deviates, a problem may occur in which the temperature distribution on the mounting surface deviates from the design.

[0006] The present invention has been made based on the recognition of the above problem, and has an object to provide an electrostatic chuck that can suppress the influence of misalignment of the coolant flow path. [Means for solving the problem]

[0007] A first invention is an electrostatic chuck comprising: a ceramic dielectric substrate having a mounting surface on which an object to be processed is placed; and a base plate supporting the ceramic dielectric substrate and having an upper surface facing the ceramic dielectric substrate and a lower surface opposite the upper surface, wherein the base plate includes a communicating passage provided between the upper surface and the lower surface and allowing a coolant to pass through, the communicating passage including a first flow path portion having a pair of side surfaces along a first direction along the flow of the coolant, one of the pair of side surfaces having a plurality of convex portions convex in a second direction extending from the other of the pair of side surfaces to the one of the pair of side surfaces, which is a second direction perpendicular to the first direction when viewed along a stacking direction of the base plate and the ceramic dielectric substrate, and a plurality of concave portions convex in a direction opposite to the second direction, wherein the plurality of convex portions and the plurality of concave portions are arranged alternately.

[0008] According to this electrostatic chuck, a plurality of protrusions and a plurality of recesses are alternately arranged on at least one side surface of the communication passage, so that even if the position of the communication passage is deviated from the design, deviation of the temperature distribution on the mounting surface of the ceramic dielectric substrate from the design can be minimized.

[0009] A second invention is an electrostatic chuck according to the first invention, characterized in that the other of the pair of side surfaces has, when viewed along the stacking direction, a plurality of convex portions convex in the second direction and a plurality of concave portions convex in a direction opposite to the second direction, and the plurality of convex portions on the other side surface and the plurality of concave portions on the other side surface are arranged alternately.

[0010] In this electrostatic chuck, a plurality of protrusions and a plurality of recesses are alternately arranged on both side surfaces of the communication passage, which makes it possible to further suppress deviation of the temperature distribution on the mounting surface from the design due to misalignment of the communication passage.

[0011] A third invention is an electrostatic chuck according to the first or second invention, wherein the first direction is a circumferential direction of the base plate, the plurality of convex portions on the one side surface include a first convex portion, the plurality of concave portions on the one side surface include a first concave portion adjacent to the first convex portion, and when a virtual circle tangent to the first convex portion and centered on the center of the base plate is defined as a first virtual circle, and a virtual circle tangent to the first concave portion and centered on the center of the base plate is defined as a second virtual circle, a first distance between the first virtual circle and the second virtual circle is longer than the shortest distance between the one side surface and the other side surface.

[0012] According to this electrostatic chuck, since the first distance is long, even if the positional deviation of the communication passage becomes somewhat large during the manufacture of the electrostatic chuck, deviation of the temperature distribution on the mounting surface from the design can be suppressed.

[0013] A fourth invention is the electrostatic chuck according to the third invention, characterized in that the first distance is 5 millimeters or more.

[0014] According to this electrostatic chuck, since the first distance is long, even if the positional deviation of the communication passage becomes somewhat large during the manufacture of the electrostatic chuck, deviation of the temperature distribution on the mounting surface from the design can be suppressed.

[0015] a first imaginary circle that is in contact with the first convex portion and has its center at the center of the base plate as a first imaginary circle; a second imaginary circle that is in contact with the first concave portion and has its center at the center of the base plate as a second imaginary circle; a third imaginary circle that is equidistant from the first imaginary circle; a first radial line that is a line connecting the first convex portion and the center of the base plate; and a second radial line that is a line connecting the first concave portion and the center of the base plate; a second distance along the circumferential direction between an intersection of the first radial line and the third imaginary circle and an intersection of the second radial line and the third imaginary circle is 30 millimeters or more and 140 millimeters or less.

[0016] According to this electrostatic chuck, the second distance is shorter than the predetermined value, and therefore it is possible to further suppress deviation of the temperature distribution on the mounting surface from the design due to misalignment of the communication passage.

[0017] A sixth invention is an electrostatic chuck according to any one of the first to fifth inventions, characterized in that the first direction is a circumferential direction of the base plate, and the one side surface is located closer to the outer periphery of the base plate than the other side surface.

[0018] When the first flow path portion of the communication passage extends along the circumferential direction of the base plate, if the position of the first flow path portion deviates from the design, the misalignment may have a greater effect on the temperature distribution on the outer side of the first flow path portion than on the inner side of the first flow path portion. In contrast, this electrostatic chuck has multiple protrusions and multiple recesses on the outer peripheral side. This makes it possible to further suppress deviation of the temperature distribution on the mounting surface from the design on the outer peripheral side of the first flow path portion.

[0019] A seventh invention is the electrostatic chuck according to the third or fourth invention, wherein the communicating passage includes a second flow path portion having a pair of side surfaces aligned in a radial direction of the base plate, and one of the pair of side surfaces of the second flow path portion has, when viewed along the stacking direction, a plurality of convex portions convex in the second direction and a plurality of concave portions convex in a direction opposite to the second direction, the plurality of convex portions of the second flow path portion and the plurality of concave portions of the second flow path portion are arranged alternately, the second flow path portion is located closer to an inner circumference of the base plate than the first flow path portion, the plurality of convex portions of the second flow path portion include second convex portions, and the plurality of concave portions of the second flow path portion include second concave portions, and wherein a fourth imaginary circle is a virtual circle that is in contact with the second convex portions and has its center at the center of the base plate, and a fifth imaginary circle is a virtual circle that is in contact with the second concave portions and has its center at the center of the base plate, and the distance between the fourth imaginary circle and the fifth imaginary circle is a third distance, and the first distance is longer than the third distance.

[0020] When the positions of the first flow path portion and the second flow path portion of the communication passage extending along the circumferential direction are deviated from the design, the misalignment may have a greater effect on the temperature distribution in the first flow path portion located on the outer periphery side than the second flow path portion located on the inner periphery side of the base plate.In contrast, with this electrostatic chuck, the first distance in the first flow path portion located on the outer periphery side is longer than the third distance in the second flow path portion located on the inner periphery side, so that the deviation of the temperature distribution on the mounting surface from the design can be further suppressed in the first flow path portion located on the outer periphery side.

[0021] An eighth invention is related to the fifth invention, wherein the communication passage includes a second flow path section having a pair of side surfaces aligned in a radial direction of the base plate, one of the pair of side surfaces of the second flow path section has, when viewed along the stacking direction, a plurality of convex portions convex in the second direction and a plurality of concave portions convex in a direction opposite to the second direction, the plurality of convex portions of the second flow path section and the plurality of concave portions of the second flow path section are arranged alternately, the second flow path section is located closer to an inner periphery of the base plate than the first flow path section, the plurality of convex portions of the second flow path section include second convex portions, the plurality of concave portions of the second flow path section include second concave portions, and the base plate is in contact with the second convex portions. a fourth virtual circle is a virtual circle centered on the center of the base plate, a fifth virtual circle is a virtual circle tangent to the first recess and centered on the center of the base plate, a sixth virtual circle is a virtual circle whose distance from the fourth virtual circle is equal to that from the fifth virtual circle, a third radial line is a straight line connecting the second recess and the center of the base plate, and a fourth radial line is a straight line connecting the second recess and the center of the base plate, where a fourth distance is a distance along the circumferential direction between an intersection of the third radial line and the sixth virtual circle and an intersection of the fourth radial line and the sixth virtual circle, the second distance is shorter than the fourth distance.

[0022] According to this electrostatic chuck, the second distance (e.g., the meandering period) in the first flow path section on the outer periphery is shorter than the fourth distance (e.g., the meandering period) in the second flow path section on the inner periphery, so that deviation of the temperature distribution on the mounting surface from the design can be further suppressed in the first flow path section on the outer periphery.

[0023] A ninth invention is an electrostatic chuck according to the first or second invention, characterized in that the first direction is a linear direction, the multiple convex portions on the one side surface include a first convex portion, the multiple concave portions on the one side surface include a first concave portion adjacent to the first convex portion, and when a straight line tangent to the first convex portion and extending in the first direction is defined as a first straight line, and a straight line tangent to the first concave portion and extending in the first direction is defined as a second straight line, a fifth distance between the first straight line and the second straight line is longer than the shortest distance between the one side surface and the other side surface.

[0024] With this electrostatic chuck, the fifth distance (e.g., the amount of meandering of the side surface of the communicating passage) is long, so that even if the positional deviation of the communicating passage becomes somewhat large during manufacturing of the electrostatic chuck, deviation of the temperature distribution on the mounting surface from the design can be suppressed.

[0025] A tenth aspect of the present invention is the electrostatic chuck according to the ninth aspect of the present invention, characterized in that the fifth distance is 5 millimeters or more.

[0026] With this electrostatic chuck, the fifth distance (e.g., the amount of meandering of the side surface of the communicating passage) is long, so that even if the positional deviation of the communicating passage becomes somewhat large during manufacturing of the electrostatic chuck, deviation of the temperature distribution on the mounting surface from the design can be suppressed.

[0027] An eleventh invention is an electrostatic chuck according to the first or second invention, wherein the first direction is a linear direction, the plurality of convex portions on the one side surface include a first convex portion, and the plurality of concave portions on the one side surface include a first concave portion adjacent to the first convex portion; a first line is a line tangent to the first convex portion and extending in the first direction, a second line is a line tangent to the first concave portion and extending in the first direction, a third line is a line that is equal to the distance from the first line and the distance from the second line, a first vertical line is a line that passes through the first convex portion and is perpendicular to the first line, and a second vertical line is a line that passes through the first concave portion and is perpendicular to the second line, a sixth distance between an intersection of the first vertical line and the third line and an intersection of the second vertical line and the third line is 30 millimeters or more and 140 millimeters or less.

[0028] According to this electrostatic chuck, the sixth distance (for example, the meandering period of the side surface of the communication path) is short, so that deviation of the temperature distribution on the mounting surface from the design due to misalignment of the communication path can be further suppressed.

[0029] A twelfth invention is an electrostatic chuck according to any one of the first to eleventh inventions, further comprising a heater section provided inside the ceramic dielectric substrate or between the ceramic dielectric substrate and the base plate, the heater section including a heater line having a pair of sides extending along an extension direction of the heater line, and at least a portion of one of the pair of sides overlapping with the first flow path section in the stacking direction.

[0030] If the position of the communication passage that cools the mounting surface deviates from the design relative to the heater that heats the mounting surface, the temperature distribution on the mounting surface is likely to deviate significantly from the design. In contrast, with this electrostatic chuck, at least a portion of one side of the heater overlaps with the first flow path portion of the communication passage, so that even if the position of the communication passage relative to the heater deviates from the design, the deviation of the temperature distribution on the mounting surface from the design can be further suppressed.

[0031] A thirteenth aspect of the present invention is the electrostatic chuck according to the twelfth aspect of the present invention, wherein the extending direction is the same as the first direction.

[0032] According to this electrostatic chuck, the plurality of recesses and protrusions of the first flow path portion are arranged alternately along the extension direction of the heater line, which makes it possible to further suppress deviation of the temperature distribution on the mounting surface from the design even when the position of the communication path relative to the heater portion is deviated from the design. [Effects of the Invention]

[0033] According to an aspect of the present invention, an electrostatic chuck is provided that can suppress the influence of misalignment of a coolant flow path. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a perspective view schematically illustrating an electrostatic chuck according to an embodiment. [Figure 2] 2(a) and 2(b) are cross-sectional views schematically illustrating a part of an electrostatic chuck according to an embodiment. [Figure 3] 3(a) and 3(b) are cross-sectional views schematically illustrating a part of an electrostatic chuck according to a modified example of the embodiment. [Figure 4] FIG. 1 is a cross-sectional view schematically illustrating a portion of an electrostatic chuck according to an embodiment. [Figure 5] FIG. 1 is a cross-sectional view schematically illustrating a portion of an electrostatic chuck according to an embodiment. [Figure 6] FIG. 1 is a cross-sectional view schematically illustrating a portion of an electrostatic chuck according to an embodiment. [Figure 7] 7(a) to 7(f) are schematic cross-sectional views illustrating an example of a method for manufacturing an electrostatic chuck according to the embodiment. [Figure 8] 8(a) to 8(d) are schematic diagrams showing a simulation of the temperature distribution of the electrostatic chuck. [Figure 9] 9(a) to 9(f) are schematic diagrams showing simulations of the temperature distribution of the electrostatic chuck. [Figure 10]FIG. 1 is a perspective view schematically illustrating a portion of an electrostatic chuck according to an embodiment. [Figure 11] 11(a) and 11(b) are perspective plan views that schematically show a part of the electrostatic chuck according to the embodiment. [Figure 12] FIG. 10 is a cross-sectional view schematically illustrating a portion of another electrostatic chuck according to an embodiment. [Figure 13] FIG. 1 is a cross-sectional view schematically illustrating a portion of an electrostatic chuck according to an embodiment. [Figure 14] FIG. 1 is a cross-sectional view schematically illustrating a portion of an electrostatic chuck according to an embodiment. [Figure 15] FIG. 2 is a perspective plan view schematically illustrating a portion of the electrostatic chuck according to the embodiment. [Figure 16] 16(a) and 16(b) are perspective plan views that schematically show a part of the electrostatic chuck according to the embodiment. [Figure 17] FIG. 10 is a cross-sectional view schematically illustrating a portion of another electrostatic chuck according to an embodiment. [Figure 18] FIG. 10 is a cross-sectional view schematically illustrating a portion of another electrostatic chuck according to an embodiment. [Figure 19] FIG. 10 is a cross-sectional view schematically illustrating a portion of another electrostatic chuck according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, like components are designated by like reference numerals and detailed descriptions thereof will be omitted where appropriate. FIG. 1 is a perspective view schematically illustrating an electrostatic chuck according to an embodiment. 2(a) and 2(b) are cross-sectional views schematically illustrating a part of an electrostatic chuck according to an embodiment. For convenience of explanation, FIG. 1 shows a cross-sectional view of a part of the electrostatic chuck. FIG. 2(a) is a cross-sectional view taken along line A1-A1 shown in FIG. Fig. 2(b) is an enlarged view of an area B2 shown in Fig. 2(a). Note that the processing object W is omitted in Fig. 2(b).

[0036] As shown in FIGS. 1, 2(a), and 2(b), the electrostatic chuck 10 according to the embodiment includes a ceramic dielectric substrate 100, a heater portion 200, and a base plate 300.

[0037] The ceramic dielectric substrate 100 is a flat base material made of, for example, a polycrystalline ceramic sintered body, and has a first main surface 101 (mounting surface) on which a processing object W such as a semiconductor wafer is placed, and a second main surface 102 opposite to the first main surface 101.

[0038] In this specification, the direction perpendicular to the first main surface 101 is defined as the Z direction. In other words, the Z direction is the direction connecting the first main surface 101 and the second main surface 102. In other words, the Z direction is the direction from the base plate 300 toward the ceramic dielectric substrate 100. One of the directions perpendicular to the Z direction is defined as the X direction, and the direction perpendicular to the Z direction and the X direction is defined as the Y direction. In this specification, "in-plane" refers to, for example, the XY plane. In this specification, "planar view" refers to a state viewed along the Z direction.

[0039] Examples of the crystalline material contained in the ceramic dielectric substrate 100 include Al2O3, AlN, SiC, Y2O3, and YAG. By using such materials, the infrared transmittance, thermal conductivity, insulation resistance, and plasma durability of the ceramic dielectric substrate 100 can be improved.

[0040] An electrode layer 111 is provided inside the ceramic dielectric substrate 100. The electrode layer 111 is interposed between the first main surface 101 and the second main surface 102. In other words, the electrode layer 111 is formed so as to be inserted into the ceramic dielectric substrate 100. The electrode layer 111 is sintered integrally with the ceramic dielectric substrate 100.

[0041] The electrode layer 111 is not limited to being interposed between the first main surface 101 and the second main surface 102, but may be provided on the second main surface 102.

[0042] The electrostatic chuck 10 applies an attracting and holding voltage to the electrode layer 111 to generate an electric charge on the first main surface 101 side of the electrode layer 111, and attracts and holds the workpiece W by electrostatic force.

[0043] The electrode layer 111 is provided along the first main surface 101 and the second main surface 102. The electrode layer 111 is an adsorption electrode for adsorbing and holding the processing target W. The electrode layer 111 may be a monopolar or bipolar type. The electrode layer 111 may also be a tripolar or other multipolar type. The number of electrode layers 111 and the arrangement of the electrode layers 111 are selected appropriately.

[0044] The base plate 300 is provided on the second main surface 102 side of the ceramic dielectric substrate 100 and supports the ceramic dielectric substrate 100. As shown in FIG. 2(a), the base plate 300 has an upper surface 302 facing the ceramic dielectric substrate 100 and a lower surface 303 opposite to the upper surface 302. The base plate 300 includes a communication path 301 provided between the upper surface 302 and the lower surface 303. In other words, the communication path 301 is provided inside the base plate 300. Examples of materials for the base plate 300 include aluminum, aluminum alloys, titanium, and titanium alloys.

[0045] The base plate 300 serves to adjust the temperature of the ceramic dielectric substrate 100. For example, when cooling the ceramic dielectric substrate 100, a cooling medium flows into the communicating passages 301, passes through the communicating passages 301, and then flows out from the communicating passages 301. This allows the cooling medium to absorb heat from the base plate 300 and cool the ceramic dielectric substrate 100 mounted thereon. In other words, the communicating passages 301 function as refrigerant flow paths through which the refrigerant can pass.

[0046] As shown in FIG. 2(a), in this example, the base plate 300 includes an upper member 300a and a lower member 300b. The upper member 300a is provided on the lower member 300b. An upper surface 300bf of the lower member 300b is flat. A groove 300g (recess) that forms the communication path 301 is provided on the lower surface 300af of the upper member 300a. The lower surface 300af of the upper member 300a and the upper surface 300bf of the lower member 300b are joined together to form the communication path 301. That is, a portion of the upper surface 300bf of the lower member 300b becomes the lower surface 301b (bottom surface) of the communication path 301. The inner surface of the groove 300g of the upper member 300a becomes the upper surface 301u and side surface 301s of the communication path 301. The side surface 301s is a plane that intersects with the XY plane.

[0047] Furthermore, convex portions 113 are provided on the first main surface 101 side of the ceramic dielectric substrate 100 as needed. Grooves 115 are provided between adjacent convex portions 113. The grooves 115 communicate with each other. A space is formed between the grooves 115 and the back surface of the processing object W mounted on the electrostatic chuck 10.

[0048] An introduction path 321 that penetrates the base plate 300 and the ceramic dielectric substrate 100 is connected to the groove 115. When a transfer gas such as helium (He) is introduced from the introduction path 321 while the processing object W is held by suction, the transfer gas flows into the space provided between the processing object W and the groove 115, and the processing object W can be directly heated or cooled by the transfer gas.

[0049] The heater section 200 heats the ceramic dielectric substrate 100. The heater section 200 heats the ceramic dielectric substrate 100, thereby heating the object to be processed W through the ceramic dielectric substrate 100. In this example, the heater section 200 is provided between the first main surface 101 and the second main surface 102. That is, the heater section 200 is provided inside the ceramic dielectric substrate 100. The heater section 200 is formed so as to be inserted into the ceramic dielectric substrate 100. In other words, the heater section 200 is built into the ceramic dielectric substrate 100.

[0050] 3(a) and 3(b) are cross-sectional views schematically illustrating a part of an electrostatic chuck according to a modified example of the embodiment. Fig. 3(b) is an enlarged view of region B1 shown in Fig. 3(a). Note that the processing object W is omitted in Fig. 3(b). 3(a) and 3(b), the heater section 200 may be separate from the ceramic dielectric substrate 100. The heater section 200 is provided between the ceramic dielectric substrate 100 and the base plate 300.

[0051] An adhesive layer 403 is provided between the base plate 300 and the heater section 200. An adhesive layer 403 is provided between the heater section 200 and the ceramic dielectric substrate 100. Examples of materials for the adhesive layer 403 include heat-resistant resins such as silicone that have relatively high thermal conductivity.

[0052] FIG. 4 is a cross-sectional view schematically illustrating a portion of the electrostatic chuck according to the embodiment. 4 corresponds to the cross section taken along line A2-A2 in FIG. 2 and shows the planar shape of the base plate 300 and the communicating passage 301 as viewed from above. The planar shape of the base plate 300 is, for example, circular. Note that the term "circular" includes not only a perfect circle but also an approximately circular shape.

[0053] One end 301c of the communicating path 301 is located near the center 300c of the planar shape of the base plate 300. The other end 301d of the communicating path 301 is located on the outer periphery of the planar shape of the base plate 300. When viewed along the stacking direction, the communicating path 301 has a spiral shape connecting the one end 301c and the other end 301d. For example, the refrigerant R flows into the communicating path 301 from the one end 301c, flows through the spiral-shaped communicating path 301, and flows out of the communicating path 301 from the other end 301d. Conversely, the refrigerant R may flow into the communicating path 301 from the other end 301d, flow through the communicating path 301, and flow out of the communicating path 301 from the one end 301c.

[0054] In the embodiment, at least a portion of the communication path 301 is serpentine. For example, the communication path 301 includes a first flow path portion 311 that extends in a serpentine manner along a first direction D1. The first direction D1 is a direction perpendicular to the stacking direction (i.e., the Z direction) of the base plate 300 and the ceramic dielectric substrate 100. In this example, the first direction D1 is a circumferential direction of the planar shape of the base plate 300 (a circumferential direction centered on the center 300c). The first direction D1 is, for example, a direction along the flow of the refrigerant. For example, the direction in which the refrigerant flows inside the communication path 301 (the path along which the refrigerant flows) is along the first direction D1.

[0055] In this example, the first flow path portion 311 is provided in a region outside the central region CR of the base plate 300. The central region CR is, for example, a range within a predetermined radius centered at the center 300c in a plan view. The predetermined radius is, for example, half the radius of the base plate 300. The first flow path portion 311 is the outermost portion of the spiral-shaped communicating passage 301. However, the first flow path portion 311 may also be provided in the central region CR.

[0056] First flow path section 311 is provided to surround center 300c. For example, first flow path section 311 goes around center 300c, surrounding the entire circumference of center 300c. First flow path section 311 may be arc-shaped (part of a spiral or annular shape), or may surround center 300c over one or more revolutions (for example, two to four or more revolutions).

[0057] The outer periphery (end (outer edge) in the XY plane) of the communicating path 301 may overlap in the Z direction with the outer periphery of the object to be treated W placed on the ceramic dielectric substrate 100. In plan view, the outer periphery of the communicating path 301 may be inside or outside the outer periphery of the object to be treated W placed on the ceramic dielectric substrate 100.

[0058] The first flow path section 311 has a pair of side surfaces (inner wall surfaces) that intersect with the XY plane. The pair of side surfaces extend, for example, along a first direction D1. For example, each of the pair of side surfaces extends in a meandering manner along the first direction D1. Specifically, the first flow path section 311 has a first side surface 31 and a second side surface 32. The first side surface 31 and the second side surface 32 are part of a side surface 301s of the communication path 301.

[0059] Note that the term "a flow path portion (first flow path portion 311, second flow path portion 312 described later, etc.)" or "a side surface (first side surface 31, second side surface 32, third side surface 33, fourth side surface 34 described later, etc.) extending along the first direction D1" includes a case where the flow path portion or side surface extends in a meandering manner along the first direction D1. When the first direction D1 is the circumferential direction of the base plate 300, a shape in which the flow path portion or side surface extends around the center 300c of the base plate 300 and gradually moves away from (or approaches) the center 300c is also included in the term "a flow path portion or side surface extending along the first direction D1." For example, when the flow path portion is part of a spiral shape centered on the center 300c of the base plate 300, the flow path portion or side surface extends along the circumferential direction of the base plate 300.

[0060] Hereinafter, a case will be described in which the first side surface 31 is an outer side surface of the base plate 300, and the second side surface 32 is an inner side surface of the base plate 300. In other words, the second side surface 32 is located between the first side surface 31 and the center 300c of the base plate 300. However, the first side surface 31 may be an inner side surface of the base plate 300, and the second side surface 32 may be an outer side surface of the base plate.

[0061] The first side surface 31 and the second side surface 32 face each other and extend in the XY plane. The coolant flows between the first side surface 31 and the second side surface 32. For example, the first side surface 31 faces the second side surface 32 in the radial direction of the planar shape of the base plate 300.

[0062] At least one of the pair of side surfaces of the communicating path 301 is serpentine. That is, one of the pair of side surfaces (first side surface 31 and second side surface 32) of the communicating path 301 has multiple protrusions and multiple recesses when viewed along the Z direction. For example, the first side surface 31 has multiple protrusions 31p and multiple recesses 31q. Each of the multiple protrusions 31p is convex in the second direction D2. Each of the multiple recesses 31q is convex in a direction D3 opposite to the second direction D2. The second direction D2 is a direction in the XY plane perpendicular to the first direction D1. The second direction D2 is a direction from the other of the pair of side surfaces of the communicating path 301 (the second side surface 32) to one of the pair of side surfaces (the first side surface 31). In this example, the second direction is a radial direction of the planar shape of the base plate 300, that is, a direction from the center 300c of the base plate 300 toward the outer periphery of the base plate 300. That is, for example, in a plan view, the convex portion 31p is convex outward from the base plate 300 (for example, convex in a direction from the center toward the outer edge of the base plate 300). For example, in a plan view, the concave portion 31q is convex inward from the base plate 300 (for example, convex in a direction from the outer edge toward the center of the base plate 300).

[0063] The plurality of protrusions 31p and the plurality of recesses 31q are alternately arranged along the path along which the refrigerant flows in the communicating passage 301. The plurality of protrusions 31p and the plurality of recesses 31q are alternately arranged along the first direction D1. For example, the plurality of protrusions 31p are arranged along the first direction D1, and the plurality of recesses 31q are arranged along the first direction D1. One recess 31q connects two of the plurality of protrusions 31p that are closest to each other in the first direction D1. Furthermore, one protrusion 31p connects two of the plurality of recesses 31q that are closest to each other in the first direction D1.

[0064] In this example, both of the pair of side surfaces of the communicating path 301 are serpentine. That is, the other of the pair of side surfaces (first side surface 31 and second side surface 32) of the communicating path 301 has multiple protrusions and multiple recesses when viewed along the Z direction. That is, the second side surface 32 has multiple protrusions 32p and multiple recesses 32q. Each of the multiple protrusions 32p is convex in the second direction D2. Each of the multiple recesses 32q is convex in a direction D3 opposite to the second direction D2. That is, for example, in a plan view, the protrusions 32p are convex outward from the base plate 300 (for example, convex in a direction from the center toward the outer edge of the base plate 300). For example, in a plan view, the recesses 32q are convex inward from the base plate 300 (for example, convex in a direction from the outer edge toward the center of the base plate 300).

[0065] The plurality of protrusions 32p and the plurality of recesses 32q are alternately provided along the path along which the refrigerant flows within the communication passage 301. The plurality of protrusions 32p and the plurality of recesses 32q are alternately arranged along the first direction D1.

[0066] In a plan view, the protrusions 31p, the recesses 31q, the protrusions 32p, and the recesses 32q are each curved (e.g., arcs). However, the protrusions 31p, the recesses 31q, the protrusions 32p, and the recesses 32q may each include at least a linear portion. A portion extending along the first direction D1 may be provided between the protrusions 31p and the recesses 31q. A portion extending along the first direction D1 may be provided between the protrusions 32p and the recesses 32q.

[0067] For example, the multiple protrusions 31p include a protrusion 31pb and a protrusion 31pc. The protrusion 31pc is located more inward of the base plate 300 than the protrusion 31pb. For example, the protrusion 31pc is aligned with the protrusion 31pb in the second direction D2. However, the protrusion 31pc does not have to be aligned with the protrusion 31pb in the second direction D2. For example, the multiple recesses 31q include a recess 31qb and a recess 31qc. The recess 31qc is located more inward of the recess 31qb in the base plate 300. For example, the recess 31qc is aligned with the recess 31qb in the second direction D2. However, the recess 31qc does not have to be aligned with the recess 31qb in the second direction D2.

[0068] FIG. 5 is a cross-sectional view schematically illustrating a portion of the electrostatic chuck according to the embodiment. FIG. 5 shows an enlarged portion of FIG. 4. Each protrusion 31p has an apex 31pt (e.g., a peak). The apex 31pt is the portion of one protrusion 31p that protrudes most in the second direction D2 when viewed from a position away from the protrusion 31p in the direction D3 (e.g., the center 300c of the base plate 300). For example, the apex 31pt is the portion of the protrusion 31p that is located outermost on the base plate 300. For example, at the apex 31pt, the distance between the first side surface 31 and the center 300c is maximum. For example, at the apex 31pt, the distance between the first side surface 31 and the outer periphery 300e of the base plate 300 is minimum.

[0069] Each recess 31q has an apex 31qt (e.g., a peak). The apex 31qt is the portion of one recess 31q that is recessed most in the direction D3 when viewed from a position away from the recess 31q in the direction D3 (e.g., the center 300c of the base plate 300). For example, at the apex 31qt, the distance between the first side surface 31 and the center 300c is minimal. For example, the apex 31qt is the portion of the recess 31q that is located most inward of the base plate 300. For example, at the apex 31qt, the distance between the first side surface 31 and the outer periphery 300e of the base plate 300 is maximized.

[0070] Each protrusion 32p has an apex 32pt (e.g., a peak). The apex 32pt is the portion of one protrusion 32p that protrudes most in the second direction D2 when viewed from a position away from the protrusion 32p in the direction D3 (e.g., the center 300c of the base plate 300). For example, the apex 32pt is the portion of the protrusion 32p that is located outermost on the base plate 300. For example, at the apex 32pt, the distance between the second side surface 32 and the center 300c is maximum. For example, at the apex 32pt, the distance between the second side surface 32 and the outer periphery 300e of the base plate 300 is minimum.

[0071] Each recess 32q has an apex 32qt (e.g., a peak). The apex 32qt is the portion of one recess 32q that is recessed most in the direction D3 when viewed from a position away from the recess 32q in the direction D3 (e.g., the center 300c of the base plate 300). For example, the apex 32qt is the portion of the recess 32q that is located most inward of the base plate 300. For example, at the apex 32qt, the distance between the second side surface 32 and the center 300c is minimal. For example, at the apex 32qt, the distance between the second side surface 32 and the outer periphery 300e of the base plate 300 is maximal. Each of the apexes described above may be edges or faces instead of vertices.

[0072] As shown in FIG. 5, the first flow path portion 311 includes a first portion 311a formed by a top portion 31pt and a second portion 311b formed by a top portion 31qt. In plan view, the first portions 311a are the range between the apex 31pt and the position of the second side surface 32 that is closest to the apex 31pt. In other words, in plan view, each of the first portions 311a is the region between each of the apexes 31pt and the position of the second side surface 32 that is closest to each of the apexes 31pt. In a plan view, the second portions 311b are the range between the tops 31qt and the positions of the second side surfaces 32 that are closest to the tops 31qt. That is, in a plan view, each of the second portions 311b is the region between each of the tops 31qt and the position of the second side surfaces 32 that is closest to each of the tops 31qt. The first portions 311a and the second portions 311b are arranged alternately along the path of the refrigerant.

[0073] For example, in the range between the first portions 311a of the first flow path section 311 that are closest to each other along the refrigerant path, the direction D31p (see Figure 4) connecting the apexes 31pt located at both ends of the range is along the first direction D1 at a point within the range. For example, in the range between the second portions 311b of the first flow path section 311 that are closest to each other along the refrigerant path, the direction D31q (see Figure 4) connecting the apexes 31qt located at both ends of the range is along the first direction D1 at a point within the range.

[0074] Furthermore, for example, the direction DR1 in which the refrigerant flows within the first flow path portion 311 (hereinafter sometimes referred to as the "first refrigerant direction DR1") is along the first direction D1. In this example, the communicating passage 301 is curved and the first side surface 31 and the second side surface 32 are serpentine, so the first refrigerant direction DR1 may change along the path of the refrigerant. In this case, for example, the first refrigerant direction DR1 at any location in the first flow path portion 311 is along the first direction D1 at that location (in this example, the circumferential direction at that location).

[0075] For example, as shown in Figure 5, in the range of the first flow path section 311 between the first part 311a and the second part 311b that are adjacent to each other along the refrigerant path, the first refrigerant direction DR1 can be a direction connecting the center of the first part 311a located at one end of the range and the center of the second part 311b located at the other end of the range.

[0076] Note that "along" two directions does not only mean that the two directions are parallel, but also means that the angle between the two directions (the smaller angle between the two directions) is within a range of 50° or less or 25° or less. For example, as shown in Fig. 5, at any point in the first flow path section 311, the angle θ between the first direction D1 (circumferential direction) and the first refrigerant direction DR1 is 50° or less or 25° or less.

[0077] 5 may be used as the first refrigerant direction DR1 at any point α in the communication passage 301. In a plan view, the direction Dα is perpendicular to the line segment L that connects the first side surface 31 and the second side surface 32 at the shortest distance. The line segment L passes through the point α. Alternatively, in the range between adjacent first portions 311a of the first flow path section 311 along the refrigerant path, the direction D31p (see Figure 4) connecting the apexes 31pt located at both ends of the range may be used as the first refrigerant direction DR1. Alternatively, in the range between adjacent second portions 311b of the first flow path section 311 along the refrigerant path, the direction D31q (see Figure 4) connecting the apexes 31qt located at both ends of that range may be used as the first refrigerant direction DR1.

[0078] In this example, the width of the first flow path portion 311 is constant. For example, the convex portion 31p (top portion 31pt) is aligned with the convex portion 32p (top portion 32pt) in the second direction D2. For example, the recessed portion 31q (top portion 31qt) is aligned with the recessed portion 32q (top portion 32qt) in the second direction D2. However, in the embodiment, the width of the first flow path portion 311 may not be constant and may vary along the refrigerant path. The convex portion 31p (top portion 31pt) may not be aligned with the convex portion 32p (top portion 32pt) in the second direction D2, but may be aligned with the recessed portion 32q (top portion 32qt) in the second direction D2. The recessed portion 31q (top portion 31qt) may not be aligned with the recessed portion 32q (top portion 32qt) in the second direction D2, but may be aligned with the convex portion 32p (top portion 32pt) in the second direction D2.

[0079] FIG. 6 is a cross-sectional view schematically illustrating a portion of the electrostatic chuck according to the embodiment. 6 shows an enlarged view of a portion of FIG. 4. The plurality of protrusions 31p includes a first protrusion 31pa, which is one of the protrusions 31p. The plurality of recesses 31q includes a first recess 31qa, which is one of the recesses 31q. The first recess 31qa is adjacent to and continuous with the first protrusion 31pa. In other words, the first recess 31qa is aligned with the first protrusion 31pa in the first direction D1 and is the recess among the plurality of recesses 31q that is closest to the first protrusion 31pa.

[0080] 6 is longer than the distance La. The distance La is the shortest distance between one side surface (first side surface 31) and the other side surface (second side surface 32) of the first flow path section 311. In other words, the distance La is the width of the narrowest portion of the first flow path section 311 in a plan view. As described above, in this example, the width of the first flow path section 311 is constant.

[0081] The distance L1 corresponds to the distance between the apex 31pt of the first protrusion 31pa and the apex 31qt of the first recess 31qa along the second direction D2 (the second direction D2 at the apex 31pt or the apex 31qt). For example, the distance L1 corresponds to twice the amplitude of the meandering of the first side surface 31.

[0082] More specifically, the distance L1 is the distance (shortest distance) between the first imaginary circle IC1 and the second imaginary circle IC2 shown in FIG. 6. The first imaginary circle IC1 is an imaginary circle that is tangent to the first convex portion 31pa (the apex 31pt of the first convex portion 31pa) and has its center at the center 300c of the base plate 300. The second imaginary circle IC2 is an imaginary circle that is tangent to the first recess 31qa (the apex 31qt of the first recess 31qa) and has its center at the center 300c of the base plate 300. The distance L1 is, for example, 5 millimeters (mm) or more and 30 mm or less, preferably 10 mm or more and 15 mm or less. For example, the amplitude (half of the distance L1) may be equal to or less than the distance La. It is preferable that the distance L1 be two to three times the distance La. For example, when the distance La is 3 mm, the distance L1 is 6 to 9 mm, and when the distance La is 7 mm, the distance L1 is 14 to 21 mm.

[0083] 6 is, for example, 30 mm or more and 140 mm or less, preferably 50 mm or more and 80 mm or less. The distance L2 corresponds to the distance along the first direction D1 between the apex 31pt of the first protrusion 31pa and the apex 31qt of the first recess 31qa. For example, the distance L2 corresponds to half the length of the meandering period of the first side surface 31. The distance L2 is preferably 10 to 20 times the distance La. For example, when the distance La is 3 mm, the distance L2 is preferably 30 to 60 mm, and when the distance La is 7 mm, the distance L2 is preferably 70 to 140 mm.

[0084] More specifically, the distance L2 is the distance along the first direction D1 (circumferential direction) between points p1 and p2 shown in FIG. Point p1 is the intersection of the third imaginary circle IC3 and the first radial line R1. Point p2 is the intersection of the third imaginary circle IC3 and the second radial line R2. The third imaginary circle IC3 is an imaginary circle centered at the center 300c of the base plate 300 and located between the first imaginary circle IC1 and the second imaginary circle IC2. The distance (shortest distance) between the first imaginary circle IC1 and the third imaginary circle IC3 is equal to the distance (shortest distance) between the second imaginary circle IC2 and the third imaginary circle IC3. The first radial line R1 is a straight line passing through the center 300c of the base plate 300 and the first protrusion 31pa (the apex 31pt of the first protrusion 31pa). The second radial line R2 is a straight line passing through the center 300c of the base plate 300 and the first recess 31qa (the apex 31qt of the first recess 31qa).

[0085] The shapes of the recesses and protrusions provided on the second side surface 32 can be similarly described as those of the recesses and protrusions provided on the first side surface 31.

[0086] 7(a) to 7(f) are schematic cross-sectional views illustrating an example of a method for manufacturing an electrostatic chuck according to the embodiment. In the manufacturing process of an electrostatic chuck, the position of the communicating passage 301 (coolant flow passage) provided in the base plate 300 may deviate from the design. Figures 7(a) to 7(c) show a case where the position of the communicating passage 301 does not deviate from the design. Figures 7(d) to 7(f) show an example where the position of the communicating passage 301 deviates from the design.

[0087] As shown in FIG. 7(a), the upper member 300a is bonded onto the lower member 300b. As a result, the base plate 300 is formed as shown in FIG. 7(b). Furthermore, the ceramic dielectric substrate 100 is bonded onto the base plate 300. As a result, the electrostatic chuck 10 is manufactured as shown in FIG. 7(c). In this example, the heater unit 200 is built into the ceramic dielectric substrate 100, and the electrode 111 is omitted.

[0088] 7(d), when joining the upper member 300a and the lower member 300b, the relative positions of the upper member 300a and the lower member 300b may deviate from the design, which may result in the relative positions of the communication passages 301 with respect to the mounting surface of the ceramic dielectric substrate 100 (and the object to be processed mounted thereon) and the heater section 200 deviating from the design.

[0089] 7(e), in the manufacturing process of the ceramic dielectric substrate 100 and the heater portion 200, the relative positions of the ceramic dielectric substrate 100 and the heater portion 200 may deviate from the design, which may result in the relative position of the communicating path 301 with respect to the heater portion 200 deviating from the design.

[0090] 7(f), when the ceramic dielectric substrate 100 is joined to the base plate 300, the relative positions of the ceramic dielectric substrate 100 and the base plate 300 may deviate from the design, which may result in the relative positions of the communicating passages 301 with respect to the mounting surface of the ceramic dielectric substrate 100 (and the object to be processed mounted thereon) and the heater section 200 deviating from the design.

[0091] As described above, the electrostatic chuck 10 has a base plate 300 provided with a communication passage 301 for cooling a wafer or other object to be chucked. This coolant prevents the wafer from being overheated by heat input from plasma during processing, for example. In the electrostatic chuck 10 including the heater unit 200, the temperature of the surface on which the object to be processed is placed is controlled by heating by the heater unit 200 and cooling by the coolant. The ceramic dielectric substrate also has cooling gas inlet holes and grooves, and the temperature of the object to be chucked is controlled by helium gas or the like. The positional relationship between the cooling gas inlet holes and grooves and the communication passages is appropriately designed so that the temperature distribution on the surface on which the object to be processed is as uniform as possible.

[0092] For example, the electrostatic chuck 10 is formed by bonding a base plate and a ceramic substrate with a bonding layer. Alternatively, the base plate may be formed by bonding a plurality of members. In the manufacturing process of the electrostatic chuck 10, the position of the communicating passage 301 relative to the ceramic dielectric substrate 100 may deviate from the design. If the position of the communicating passage 301 is deviated, there is a risk of a problem in that the temperature distribution on the surface of the ceramic dielectric substrate 100 on which the workpiece is placed deviates from the design.

[0093] In contrast, in the electrostatic chuck according to the embodiment, a plurality of convex portions and a plurality of concave portions are alternately arranged on at least one side surface of the first flow path portion 311 of the communication path 301. Therefore, even if the position of the communication path is deviated from the design, it is possible to minimize deviation from the design of the temperature distribution on the mounting surface of the ceramic dielectric substrate.

[0094] 8(a) to 8(d) and 9(a) to 9(f) are schematic diagrams showing simulations of the temperature distribution of the electrostatic chuck. 8(a) to 8(d) show a model of the electrostatic chuck used in the simulation. FIGS. 8(a) and 8(b) are perspective views of the electrostatic chuck according to the reference example, as viewed from above. In FIGS. 8(a) and 8(b), region Ra corresponds to the mounting surface of the ceramic dielectric substrate, and region Rb corresponds to the communication path (coolant flow path) located below region Ra. In the electrostatic chuck according to the reference example, region Rb (communication path) does not have any irregularities. FIG. 8(b) shows a state in which the position of region Rb relative to region Ra is shifted by a distance d in the direction of the arrow from the state in FIG. 8(a).

[0095] 8(c) and 8(d) are perspective views of the electrostatic chuck according to the embodiment, as viewed from above. In FIGS. 8(c) and 8(d), region Ra corresponds to the mounting surface of the ceramic dielectric substrate, and region Rc corresponds to the communication passage (coolant flow passage) located below region Ra. In the electrostatic chuck according to the embodiment, region Rc (communication passage) is provided with irregularities. That is, region Rc has multiple portions Rc1 and multiple portions Rc2. For example, portion Rc1 corresponds to protrusion 31p, and portion Rc2 corresponds to recess 31q. FIG. 8(d) shows a state in which the position of region Rc relative to region Ra is shifted by a distance d in the direction of the arrow from the state in FIG. 8(c). The amount of shift (distance d) is the same in FIGS. 8(b) and 8(d).

[0096] 9(a) to 9(c) correspond to the temperature distribution on the mounting surface of a ceramic dielectric substrate in an electrostatic chuck according to a reference example. FIG. 9(a) corresponds to the temperature distribution when the entire model shown in FIG. 8(a) is heated while cooling region Rb with a predetermined heat amount. FIG. 9(b) corresponds to the temperature distribution when the entire model shown in FIG. 8(b) is heated while cooling region Rb with a predetermined heat amount. FIG. 9(c) shows the value obtained by subtracting the temperature in FIG. 9(a) from the temperature in FIG. 9(b). In other words, FIG. 9(c) shows the effect on the temperature distribution due to the positional deviation of region Rb.

[0097] Similarly, Figures 9(d) to 9(f) correspond to the temperature distribution on the mounting surface of the ceramic dielectric substrate in the electrostatic chuck according to the embodiment. Figure 9(d) corresponds to the temperature distribution when the entire model shown in Figure 8(c) is heated while cooling the region Rc with a predetermined heat amount. Figure 9(e) corresponds to the temperature distribution when the entire model shown in Figure 8(d) is heated while cooling the region Rc with a predetermined heat amount. Figure 9(f) shows the value obtained by subtracting the temperature in Figure 9(e) from the temperature in Figure 9(d). In other words, Figure 9(f) shows the effect on the temperature distribution due to the positional deviation of the region Rc.

[0098] Near the position of the arrow shown in FIG. 9(c), the temperature changes by 18°C ​​due to misalignment of region Rb. In contrast, near the position of the arrow shown in FIG. 9(f), the temperature changes by 3°C due to misalignment of region Rc. The temperature change in FIG. 9(f) is more gradual than the temperature change in FIG. 9(c). By providing irregularities in the communicating path, it is possible to reduce temperature changes on the mounting surface due to misalignment of the communicating path. That is, for example, by adding irregularities to the side surface of a communicating path extending in the first direction D1, the robustness of the temperature distribution against misalignment of the communicating path is improved.

[0099] In this example, as already described, a plurality of protrusions and a plurality of recesses are also provided on the other of the pair of side surfaces (first side surface 31 and second side surface 32), and the plurality of protrusions and the plurality of recesses are arranged alternately. In other words, a plurality of protrusions and a plurality of recesses are arranged alternately on both side surfaces of communicating path 301. This makes it possible to further suppress deviation of the temperature distribution on the mounting surface from the design due to misalignment of communicating path 301.

[0100] However, in the embodiment, it is sufficient that at least one of the pair of side surfaces (the first side surface 31 and the second side surface 32) has recesses and protrusions. The first side surface 31 may have protrusions and recesses, and the second side surface 32 may extend in the first direction D1 without having protrusions or recesses. For example, one of the pair of side surfaces (the first side surface 31) having multiple recesses and multiple protrusions is located closer to the outer periphery of the base plate 300 than the other side surface (the second side surface 32). When the first flow path portion 311 of the communication path 301 extends along the circumferential direction of the base plate 300, if the position of the first flow path portion 311 deviates from the design, the misalignment may have a greater effect on the temperature distribution outside the first flow path portion 311 than inside the first flow path portion 311. In response to this, multiple protrusions and multiple recesses are provided on the outer periphery side surface (the first side surface 31). This makes it possible to further suppress deviations from the design of the temperature distribution on the mounting surface on the outer periphery of the first flow path portion 311. However, the second side surface 32 may have a protrusion and a recess, and the first side surface 31 may extend in the first direction D1 without having a protrusion or a recess.

[0101] In this example, the first direction D1 is the circumferential direction of the base plate 300. As a result, for example, the first flow path portion 311 extends along the outer shape of the base plate 300 or the processing object W. As a result, for example, on the outer periphery side, it is easy to suppress the influence of misalignment on the temperature distribution.

[0102] 6, the distance L1 is longer than the distance La. The distance L1 is, for example, 5 mm or more. In this manner, by making the first distance L1 (for example, the amount of meandering of the side surface of the communicating path) long, it is possible to suppress deviation of the temperature distribution on the mounting surface from the design, even if the positional deviation of the communicating path becomes somewhat large during the manufacture of the electrostatic chuck.

[0103] 6, the second distance L2 is 30 mm or more and 140 mm or less. Because the second distance L2 (e.g., half the meandering period of the side surface of the communicating path) is shorter than a predetermined value, deviation from the design temperature distribution on the mounting surface due to misalignment of the communicating path can be further suppressed.

[0104] In the description of the embodiment, the terms "amplitude" and "period" are used for convenience. However, in the embodiment, the first distance L1 and the second distance L2 do not necessarily have to be constant over the entire circumference. In other words, the recesses and protrusions do not necessarily have to be repeated at regular intervals.

[0105] FIG. 10 is a perspective view schematically illustrating a part of the electrostatic chuck according to the embodiment. FIG. 10 shows a part of the heater section 200 and a part of the communication path 301. The heater section 200 includes a heater element 230 located above the communication path 301. The heater element 230 includes a strip-shaped conductive portion extending along the XY plane. For example, the heater element 230 is electrically connected to an external power source (not shown). An external current is supplied to the heater element 230, flowing from one end to the other end of the heater element 230. This causes the heater element 230 (heater line) to generate heat. By controlling the current flowing through the heater element 230, the amount of heat generated by the heater element 230 can be controlled, and the temperature of the mounting surface of the ceramic dielectric substrate 100 can be controlled.

[0106] A plurality of heater elements 230 may be provided. The plurality of heater elements 230 may be arranged in an XY plane. The plurality of heater elements 230 may be stacked in the Z direction with an insulating film interposed therebetween. By providing a plurality of heater elements 230, it becomes easier to control the temperature of the mounting surface and the processing object. For example, it is possible to improve the uniformity of the temperature distribution within the surface of the processing object placed on the mounting surface.

[0107] Examples of materials for the heater element 230 include metals containing at least one of stainless steel, titanium, chromium, nickel, copper, aluminum, Inconel (registered trademark), nickel, molybdenum, tungsten, palladium, platinum, silver, tantalum, molybdenum carbide, and tungsten carbide. The thickness (length in the Z direction) of the heater element 230 is, for example, approximately 0.01 mm or more and 0.20 mm or less.

[0108] 10, the heater element 230 includes a first heater element 230a and a second heater element 230b. The first heater element 230a includes first to fifth heater lines 231 to 235. The first to fifth heater lines 231 to 235 may be electrically connected to each other or may be insulated from each other. The second heater element 230b includes sixth to ninth heater lines 236 to 239. The sixth to ninth heater lines 236 to 239 may be electrically connected to each other or may be insulated from each other.

[0109] For example, the first to ninth heater lines 231 to 239 each have an arc shape extending along the first direction D1 (circumferential direction). In a plan view, the first to ninth heater lines 231 to 239 are arranged in this order from the outer periphery. That is, the first heater line 231 is the part located on the outermost periphery of the multiple heater elements 230. Note that the shape of the heater elements 230 does not necessarily have to extend along the circumferential direction or be arc-shaped.

[0110] 11(a) and 11(b) are perspective plan views that schematically show a part of the electrostatic chuck according to the embodiment. Figures 11(a) and 11(b) respectively correspond to the heater element 230 and the communicating path 301 shown in Figure 10 viewed from above. Figure 11(a) shows a case where the relative position of the communicating path 301 with respect to the heater section 200 does not deviate from the design. Figure 11(b) shows a case where the relative position of the communicating path 301 with respect to the heater section 200 deviates from the design.

[0111] In a plan view, the first heater line 231 has a first side q1 and a second side q2 that extend in the extension direction of the first heater line 231 (in this example, the circumferential direction). The first side q1 is aligned with the second side q2 in the radial direction (second direction D2). The first side q1 is positioned further outward on the base plate 300 than the second side q2. Similarly, each of the second to ninth heater lines 232 to 239 has a pair of sides (the first side q1 and the second side q2).

[0112] 11(a) and 11(b), at least one of a pair of sides of the first heater line 231 overlaps with the first flow path portion 311 in the Z direction. If the position of the communicating path 301 that cools the mounting surface deviates from the design relative to the heater portion 200 that heats the mounting surface, the temperature distribution on the mounting surface is likely to deviate from the design. In contrast, according to the embodiment, since at least a part of one side of the heater line overlaps with the first flow path portion 311 of the communicating path 301, it is possible to further suppress the deviation of the temperature distribution on the mounting surface from the design even if the position of the communicating path 301 relative to the heater portion 200 deviates from the design.

[0113] For example, the first side q1 of the first heater line 231 overlaps with the first side surface 31 in the Z direction. The second side q2 of the first heater line 231 overlaps with the second side surface 32 in the Z direction. For example, the extension direction of the first heater line 231 is the same as the first direction D1. In this case, the multiple recesses 31q and multiple protrusions 31p of the first flow path section 311 are arranged alternately along the extension direction of the first heater line. This makes it possible to further suppress deviation of the temperature distribution on the mounting surface from the design when the position of the communicating path 301 relative to the heater section 200 deviates from the design.

[0114] 11(a) and 11(b), the first flow path section 311 overlaps with the first heater line 231 and the second heater line 232 in the Z direction. The first flow path section 311 may overlap with only one heater line in the Z direction, or may overlap with three or more heater lines.

[0115] FIG. 12 is a cross-sectional view schematically illustrating a portion of another electrostatic chuck according to the embodiment. 12, like FIG. 4, illustrates a cross section of a portion of the electrostatic chuck 11 according to the embodiment, showing the planar shape of the base plate 300 and the communication passage 301 as viewed from above. The electrostatic chuck 11 includes a second flow passage portion 312 that extends, for example, in a serpentine manner along the first direction D1. Other than this, the same explanation as for the electrostatic chuck 10 can be applied to the electrostatic chuck 11.

[0116] The second flow path portion 312 is located closer to the inner periphery of the base plate 300 than the first flow path portion 311. For example, the second flow path portion 312 is located between the first flow path portion 311 and the center 300c of the base plate 300. The second flow path portion 312 may be provided in the central region CR of the base plate 300. The second flow path portion 312 is a part of a single spiral-shaped communicating path 301 and is connected to the first flow path portion 311. The second flow path portion 312 is provided to surround the center 300c. For example, the second flow path portion 312 goes around the center 300c, surrounding the entire circumference of the center 300c. However, the second flow path portion 312 may be arc-shaped (part of a spiral or annular shape) or may surround the center 300c more than once.

[0117] The second flow path section 312 has a pair of side surfaces (inner wall surfaces) that intersect with the XY plane. The pair of side surfaces extend, for example, along the first direction D1. Specifically, the second flow path section 312 has a third side surface 33 and a fourth side surface 34.

[0118] Below, a case will be described in which the third side surface 33 is an outer side surface of the base plate 300, and the fourth side surface 34 is an inner side surface of the base plate 300. In other words, the fourth side surface 34 is located between the third side surface 33 and the center 300c of the base plate 300. However, in the following description, the third side surface 33 may be an inner side surface of the base plate 300, and the fourth side surface 34 may be an outer side surface of the base plate.

[0119] The third side surface 33 and the fourth side surface 34 face each other and extend in the XY plane. The coolant flows between the third side surface 33 and the fourth side surface 34. For example, the third side surface 33 faces the fourth side surface 34 in the radial direction of the planar shape of the base plate 300.

[0120] When viewed along the Z direction, one of the pair of side surfaces (the third side surface 33 and the fourth side surface 34) of the second flow path section 312 has a plurality of protrusions and a plurality of recesses. For example, the third side surface 33 has a plurality of protrusions 33p and a plurality of recesses 33q. Each of the plurality of protrusions 33p is convex in the second direction D2. Each of the plurality of recesses 33q is convex in a direction D3 opposite to the second direction D2. That is, for example, in a plan view, the protrusions 33p are convex outward from the base plate 300 (for example, convex in a direction from the center toward the outer edge of the base plate 300). For example, in a plan view, the recesses 33q are convex inward from the base plate 300 (for example, convex in a direction from the outer edge toward the center of the base plate 300).

[0121] The plurality of protrusions 33p and the plurality of recesses 33q are alternately provided along the path along which the refrigerant flows within the communication passage 301. The plurality of protrusions 33p and the plurality of recesses 33q are alternately arranged along the first direction D1.

[0122] In this example, both of the pair of side surfaces of the second flow path section 312 are serpentine. That is, the other of the pair of side surfaces (the third side surface 33 and the fourth side surface 34) of the second flow path section 312 has a plurality of convex portions and a plurality of concave portions when viewed along the Z direction. That is, the fourth side surface 34 has a plurality of convex portions 34p and a plurality of concave portions 34q. Each of the plurality of convex portions 34p is convex in the second direction D2. Each of the plurality of concave portions 34q is convex in a direction D3 opposite to the second direction D2. That is, for example, in a plan view, the convex portions 34p are convex outward from the base plate 300 (for example, convex in a direction from the center toward the outer edge of the base plate 300). For example, in a plan view, the concave portions 34q are convex inward from the base plate 300 (for example, convex in a direction from the outer edge toward the center of the base plate 300).

[0123] The plurality of protrusions 34p and the plurality of recesses 34q are alternately provided along the path along which the refrigerant flows within the communication passage 301. The plurality of protrusions 34p and the plurality of recesses 34q are alternately arranged along the first direction D1.

[0124] In a plan view, the protrusions 33p, the recesses 33q, the protrusions 34p, and the recesses 34q are each curved (e.g., arcs). However, the protrusions 33p, the recesses 33q, the protrusions 34p, and the recesses 34q may each include at least a linear portion. A portion extending along the first direction D1 may be provided between the protrusions 33p and the recesses 33q. A portion extending along the first direction D1 may be provided between the protrusions 34p and the recesses 34q.

[0125] FIG. 13 is a cross-sectional view schematically illustrating a portion of the electrostatic chuck according to the embodiment. Fig. 13 shows an enlarged portion of Fig. 12. Each protrusion 33p has an apex 33pt (e.g., a peak). The apex 33pt is the portion of one protrusion 33p that protrudes most in the second direction D2 when viewed from a position away from the protrusion 33p in direction D3 (e.g., the center 300c of the base plate 300). For example, the apex 33pt is the portion of the protrusion 33p that is located outermost on the base plate 300 (the portion farthest from the center 300c in a plan view).

[0126] Each recess 33q has an apex 33qt (e.g., a peak). The apex 33qt is the portion of one recess 33q that is recessed most in the direction D3 when viewed from a position farthest from the recess 33q in the direction D3 (e.g., the center 300c of the base plate 300). For example, the apex 33qt is the portion of the recess 33q that is located most inward of the base plate 300 (the portion closest to the center 300c in a plan view).

[0127] Each protrusion 34p has an apex 34pt (e.g., a peak). The apex 34pt is the portion of one protrusion 34p that protrudes most in the second direction D2 when viewed from a position away from the protrusion 34p in the direction D3 (e.g., the center 300c of the base plate 300). For example, the apex 34pt is the portion of the protrusion 34p that is located at the outermost side of the base plate 300.

[0128] Each recess 34q has an apex 34qt (e.g., a corner). The apex 34qt is the portion of one recess 34q that is recessed most in the direction D3 when viewed from a position away from the recess 34q in the direction D3 (e.g., the center 300c of the base plate 300). For example, the apex 34qt is the portion of the recess 34q that is located most inward of the base plate 300. Each of the apexes described above may be sides instead of vertices.

[0129] As shown in FIG. 13, the second flow path portion 312 includes a third portion 312a formed by the apex 33pt and a fourth portion 312b formed by the apex 33qt. In plan view, the third portion 312a is the range between the apex 33pt and the position of the fourth side surface 34 that is closest to the apex 33pt. In other words, each of the third portions 312a is, in plan view, the region between each of the vertices 33pt and the position of the fourth side surface 34 that is closest to each of the vertices 33pt. In a plan view, the fourth portions 312b are the range between the apex 33qt and the position of the fourth side surface 34 that is closest to the apex 33qt. In other words, in a plan view, each of the fourth portions 312b is the region between each of the vertices 33qt and the position of the fourth side surface 34 that is closest to each of the vertices 33qt. The third portions 312a and the fourth portions 312b are arranged alternately along the path of the refrigerant.

[0130] For example, in the range between the third portions 312a of the second flow path section 312 that are closest to each other along the refrigerant path, the direction D33p (see Figure 12) connecting the apexes 33pt located at both ends of the range is along the first direction D1 at a point within the range. For example, in the range between the fourth portions 312b of the second flow path section 312 that are closest to each other along the refrigerant path, the direction D33q (see Figure 12) connecting the apexes 33qt located at both ends of the range is along the first direction D1 at a point within the range.

[0131] Furthermore, for example, the direction DR2 in which the refrigerant flows within the second flow path portion 312 (hereinafter sometimes referred to as the "second refrigerant direction DR2") is along the first direction D1. In this example, the communicating passage 301 is curved and the third side surface 33 and the fourth side surface 34 are serpentine, so the second refrigerant direction DR2 changes along the path of the refrigerant. In this case, for example, the second refrigerant direction DR2 at any location in the second flow path portion 312 is along the first direction D1 at that location (in this example, the circumferential direction at that location).

[0132] For example, as shown in FIG. 13, in the second flow path section 312, between the third portion 312a and the fourth portion 312b that are adjacent to each other along the refrigerant path, the second refrigerant direction DR2 can be a direction connecting the center of the third portion 312a and the center of the fourth portion 312b.

[0133] 13 may be used as the second refrigerant direction DR2 at an arbitrary point β in the communicating passage 301. In a plan view, the direction Dβ is perpendicular to a line segment Lβ that connects the third side surface 33 and the fourth side surface 34 at the shortest distance. The line segment Lβ passes through the arbitrary point β. Alternatively, in the range between adjacent third portions 312a of the second flow path section 312 along the refrigerant path, the direction D33p (see Figure 12) connecting the apexes 33pt located at both ends of that range may be used as the second refrigerant direction DR2. Alternatively, in the range between adjacent fourth portions 312b of the second flow path section 312 along the refrigerant path, the direction D33q (see Figure 12) connecting the apexes 33qt located at both ends of that range may be used as the second refrigerant direction DR2.

[0134] The width of the second flow path portion 312 may be constant. For example, the convex portion 33p (top portion 33pt) is aligned with the convex portion 34p (top portion 34pt) in the second direction D2. For example, the recessed portion 33q (top portion 33qt) is aligned with the recessed portion 34q (top portion 34qt) in the second direction D2. However, in the embodiment, the width of the second flow path portion 312 may not be constant and may vary along the refrigerant path. The convex portion 33p (top portion 33pt) may not be aligned with the convex portion 34p (top portion 34pt) in the second direction D2, but may be aligned with the recessed portion 34q (top portion 34qt) in the second direction D2. The recessed portion 33q (top portion 33qt) may not be aligned with the recessed portion 34q (top portion 34qt) in the second direction D2, but may be aligned with the convex portion 34p (top portion 34pt) in the second direction D2.

[0135] FIG. 14 is a cross-sectional view schematically illustrating a portion of the electrostatic chuck according to the embodiment. Figure 14 shows an enlarged portion of Figure 12. The multiple protrusions 33p include a second protrusion 33pa, which is one of the protrusions 33p. The multiple recesses 33q include a second recess 33qa, which is one of the recesses 33q. The second recess 33qa is adjacent to and continuous with the second protrusion 33pa. In other words, the second recess 33qa is aligned with the second protrusion 33pa in the first direction D1 and is the recess among the multiple recesses 33q that is closest to the second protrusion 33pa.

[0136] 14 is longer than distance Lb. Distance Lb is the shortest distance between one side surface (third side surface 33) and the other side surface (fourth side surface 34) of second flow path section 312. In other words, distance Lb is the width of the narrowest portion of second flow path section 312 in a plan view.

[0137] The distance L3 corresponds to the distance along the second direction D2 (the second direction D2 at the apex 33pt or the apex 33qt) between the apex 33pt of the second protrusion 33pa and the apex 33qt of the second recess 33qa. For example, the distance L3 corresponds to twice the amplitude of the meandering of the third side surface 33.

[0138] 14. The fourth imaginary circle IC4 is a virtual circle that is tangent to the second convex portion 33pa (the apex 33pt of the second convex portion 33pa) and has its center at the center 300c of the base plate 300. The fifth imaginary circle IC5 is a virtual circle that is tangent to the second recess 33qa (the apex 33qt of the second recess 33qa) and has its center at the center 300c of the base plate 300. The distance L3 is, for example, not less than 5 millimeters (mm) and not more than 30 mm.

[0139] For example, distance L3 (third distance) of second flow path portion 312 is shorter than distance L1 (first distance) of first flow path portion 311. When the positions of first flow path portion 311 and second flow path portion 312 of communicating passage 301 extending along the circumferential direction deviate from the design, the positional deviation may have a greater effect on the temperature distribution in first flow path portion 311 located on the outer periphery side than second flow path portion 312 located on the inner periphery side of base plate 300. In contrast, because the first distance in first flow path portion 311 on the outer periphery side is longer than the third distance in second flow path portion 311 on the inner periphery side, deviation of the temperature distribution on the mounting surface from the design can be further suppressed in the first flow path portion on the outer periphery side.

[0140] 14 is, for example, 30 mm or more and 140 mm or less. The distance L2 corresponds to the distance along the first direction D1 between the apex 33pt of the second protrusion 33pa and the apex 33qt of the second recess 33qa. For example, the distance L4 corresponds to half the length of the meandering period of the third side surface 33.

[0141] More specifically, the distance L4 is the distance along the first direction D1 (circumferential direction) between points p3 and p4 shown in FIG. Point p3 is the intersection of the sixth imaginary circle IC6 and the third radial line R3. Point p4 is the intersection of the sixth imaginary circle IC6 and the fourth radial line R4. The sixth imaginary circle IC6 is a virtual circle centered at the center 300c of the base plate 300 and located between the fourth imaginary circle IC4 and the fifth imaginary circle IC5. The distance (shortest distance) between the fourth imaginary circle IC4 and the sixth imaginary circle IC6 is equal to the distance (shortest distance) between the fifth imaginary circle IC5 and the sixth imaginary circle IC6. The third radial line R3 is a straight line passing through the center 300c of the base plate 300 and the second convex portion 33pa (the apex 33pt of the second convex portion 33pa). The fourth radial line R4 is a straight line passing through the center 300c of the base plate 300 and the second recessed portion 33qa (the apex 33qt of the second recessed portion 33qa).

[0142] For example, distance L4 (fourth distance) of second flow path section 312 is longer than distance L2 (second distance) of first flow path section 311. Since the second distance (e.g., meandering period) in first flow path section 311 on the outer periphery side is shorter than the fourth distance (e.g., meandering period) in second flow path section 312 on the inner periphery side, deviation of the temperature distribution on the mounting surface from the design can be further suppressed in the first flow path section on the outer periphery side.

[0143] The shapes of the recesses and protrusions provided on the fourth side surface 34 can be explained in the same manner as the shapes of the recesses and protrusions provided on the third side surface 33.

[0144] 15, 16(a) and 16(b) are perspective plan views that schematically show a part of the electrostatic chuck according to the embodiment. 15 shows the heater element 230 and the communication path 301 of the electrostatic chuck 11. In this example, the heater element 230 includes first to seventh heater lines 231 to 237. The planar shape of each heater line is, for example, annular.

[0145] Figures 16(a) and 16(b) are views corresponding to a portion of the heater element 230 and the communicating path 301 shown in Figure 15. Figure 16(a) shows a case where the relative position of the communicating path 301 with respect to the heater section 200 does not deviate from the design. Figure 16(b) shows a case where the relative position of the communicating path 301 with respect to the heater section 200 deviates from the design.

[0146] 16(a) and 16(b), at least one of a pair of sides of the first heater line 231 overlaps with the first flow path portion 311 in the Z direction. Also, as shown in Fig. 15, for example, at least one of a pair of sides of the third heater line 233 overlaps with the second flow path portion 312 in the Z direction. This makes it possible to further suppress deviation of the temperature distribution on the mounting surface from the design when the position of the communicating path 301 relative to the heater portion 200 deviates from the design.

[0147] For example, the second flow path section 312 overlaps in the Z direction with the second heater line 232 and the third heater line 233. The second flow path section 312 may overlap with only one heater line, or may overlap with multiple heater lines.

[0148] FIG. 17 is a cross-sectional view schematically illustrating a portion of another electrostatic chuck according to the embodiment. 17 shows the planar shape of the base plate 300 and the communication passages 301 of the electrostatic chuck 12 according to the embodiment, as viewed from above. Unlike the electrostatic chuck 10, the planar shape of the communication passages 301 of the electrostatic chuck 12 is not spiral-shaped, but rather has a zigzag or serpentine shape, for example. In this example, the first direction D1 is a direction on a straight line Ly parallel to the Y direction, and is the Y direction or a direction opposite to the Y direction. The second direction D2 is a direction perpendicular to the first direction D1.

[0149] In the electrostatic chuck 12, the communication passage 301 also includes a first flow path portion 311. The first flow path portion 311 includes a first side surface 31 and a second side surface 32. The first flow path portion 311, the first side surface 31, and the second side surface 32 each extend, for example, in a serpentine manner along the first direction D1. The first side surface 31 includes a plurality of protrusions 31p and a plurality of recesses 31q. The second side surface 32 includes a plurality of protrusions 32p and a plurality of recesses 32q. The direction connecting the tops of the protrusions 31p that are closest to each other among the plurality of protrusions 31p is along the first direction D1, for example, parallel to the first direction D1. The direction connecting the tops of the recesses 31q that are closest to each other among the plurality of recesses 31q is along the first direction D1, for example, parallel to the first direction D1.

[0150] For example, a plurality of first flow path portions 311 may be provided and aligned in the second direction D2. The communicating passage 301 may have a flow path portion 313 adjacent to the first flow path portion 311 in the second direction D2. In the flow path portion 313, the refrigerant flows in the direction opposite to the first direction D1. Except for this, the shape of the flow path portion 313 may be the same as that of the first flow path portion 311. That is, the flow path portion 313 extends, for example, in a meandering manner along the first direction D1. Each of the pair of side surfaces of the flow path portion 313 extends, for example, in a meandering manner along the first direction D1. Each of the pair of side surfaces of the flow path portion 313 includes a plurality of convex portions convex in the second direction D2 and a plurality of concave portions convex in the direction D3. The communicating passage 313 and the first flow path portion 311 are connected by a bent portion of the communicating passage 301.

[0151] The communicating passage 301 also includes a second flow path portion 312. The second flow path portion 312 includes a third side surface 33 and a fourth side surface 34. The second flow path portion 312, the third side surface 33, and the fourth side surface 34 each extend, for example, in a serpentine manner, along the first direction D1. The third side surface 33 includes a plurality of protrusions 33p and a plurality of recesses 33q. The fourth side surface 34 includes a plurality of protrusions 34p and a plurality of recesses 34q. The direction connecting the tops of the protrusions 33p that are closest to each other among the plurality of protrusions 33p is along the first direction D1, for example, parallel to the first direction D1. The direction connecting the tops of the recesses 33q that are closest to each other among the plurality of recesses 33q is along the first direction D1, for example, parallel to the first direction D1.

[0152] For example, a plurality of second flow path portions 312 may be provided and aligned in the second direction D2. The communicating passage 301 may have a flow path portion 314 adjacent to the second flow path portion 312 in the second direction D2. In the flow path portion 314, the refrigerant flows in the direction opposite to the first direction D1. Except for this, the shape of the flow path portion 314 may be the same as that of the second flow path portion 312. That is, the flow path portion 314 extends, for example, in a meandering manner along the first direction D1. Each of the pair of side surfaces of the flow path portion 314 extends, for example, in a meandering manner along the first direction D1. Each of the pair of side surfaces of the flow path portion 314 includes a plurality of convex portions convex in the second direction D2 and a plurality of concave portions convex in the direction D3. The flow path portion 314 and the second flow path portion 312 are connected by a bent portion of the communicating passage 301.

[0153] FIG. 18 is a cross-sectional view schematically illustrating a portion of another electrostatic chuck according to the embodiment. FIG. 18 shows an enlarged view of a part of the first flow path section 311 shown in FIG. The plurality of protrusions 31p includes a first protrusion 31pa, which is one of the protrusions 31p. The plurality of recesses 31q includes a first recess 31qa, which is one of the recesses 31q. 18 is longer than, for example, the distance La. The distance La is the shortest distance between one side surface (first side surface 31) and the other side surface (second side surface 32) of the first flow path section 311.

[0154] Distance L5 is the distance (shortest distance) between the first straight line IL1 and the second straight line IL2 shown in Fig. 18. The first straight line IL1 is a straight line that is tangent to the first convex portion 31pa (the apex 31pt of the first convex portion 31pa) and extends in the first direction D1. The second straight line IL2 is a straight line that is tangent to the first recess 31qa (the apex 31qt of the first recess 31qa) and extends in the first direction D1. Distance L5 is, for example, not less than 5 millimeters (mm) and not more than 30 mm.

[0155] The distance L6 (sixth distance) shown in FIG. 18 is, for example, 30 mm or more and 140 mm or less. The distance L6 is the distance along the first direction D1 between points p5 and p6 shown in FIG. 18. Point p5 is the intersection of the third line IL3 and the first vertical line V1. Point p6 is the intersection of the third line IL3 and the second vertical line V2. The third line IL3 is a line located between the first line IL1 and the second line IL2. The distance (shortest distance) between the first line IL1 and the third line IL3 is equal to the distance (shortest distance) between the second line IL2 and the third line IL3. The first vertical line V1 is a line that passes through the first convex portion 31pa (the apex 31pt of the first convex portion 31pa) and is perpendicular to the first line IL1. The second vertical line V2 is a line that passes through the first recess 31qa (the top 31qt of the first recess 31qa) and is perpendicular to the second line IL2.

[0156] Since the fifth distance (e.g., the amount of meandering of the side surface of the communicating path) is relatively long, deviation of the temperature distribution on the mounting surface from the design can be suppressed even if the positional deviation of the communicating path becomes somewhat large during manufacturing of the electrostatic chuck. Since the sixth distance (e.g., the period of meandering of the side surface of the communicating path) is short, deviation of the temperature distribution on the mounting surface from the design due to the positional deviation of the communicating path can be further suppressed.

[0157] In the example of FIG. 18, the convex portion 31p (top portion 31pt) is aligned with the convex portion 32p (top portion 32pt) in the second direction D2. Furthermore, the concave portion 31q (top portion 31qt) is aligned with the concave portion 32q (top portion 32qt) in the second direction D2. This allows the width of the first flow path portion 311 to be constant. However, the convex portion 31p (top portion 31pt) does not have to be aligned with the convex portion 32p (top portion 32pt) in the second direction D2. The concave portion 31q (top portion 31qt) does not have to be aligned with the concave portion 32q (top portion 32qt) in the second direction D2.

[0158] FIG. 19 is a cross-sectional view schematically illustrating a portion of another electrostatic chuck according to the embodiment. FIG. 19 shows an enlarged view of a part of the first flow path section 311 shown in FIG. The plurality of protruding portions 33p includes a second protruding portion 33pa, which is one of the protruding portions 33p. The plurality of recessed portions 33q includes a second recessed portion 33qa, which is one of the recessed portions 33q. 19 is longer than the distance Lb, which is the shortest distance between one side surface (third side surface 33) and the other side surface (fourth side surface 34) of the second flow path section 332.

[0159] Distance L7 is the distance (shortest distance) between the fourth line IL4 and the fifth line IL5 shown in Fig. 19. The fourth line IL4 is a line that is tangent to the second convex portion 33pa (the apex 33pt of the second convex portion 33pa) and extends in the first direction D1. The fifth line IL5 is a line that is tangent to the second recess 33qa (the apex 33qt of the second recess 33qa) and extends in the first direction D1. Distance L7 is, for example, not less than 5 millimeters (mm) and not more than 30 mm.

[0160] The distance L8 shown in FIG. 19 is, for example, 30 mm or more and 140 mm or less. The distance L8 is the distance along the first direction D1 between points p7 and p8 shown in FIG. 19. Point p7 is the intersection of the sixth line IL6 and the third vertical line V3. Point p8 is the intersection of the sixth line IL6 and the fourth vertical line V4. The sixth line IL6 is a line located between the fourth line IL4 and the fifth line IL5. The distance (shortest distance) between the fourth line IL4 and the sixth line IL6 is equal to the distance (shortest distance) between the fifth line IL5 and the sixth line IL6. The third vertical line V3 is a line that passes through the second convex portion 33pa (the apex 33pt of the second convex portion 33pa) and is perpendicular to the fourth line IL4. The fourth vertical line V4 is a line that passes through the second recess 33qa (the top 33qt of the second recess 33qa) and is perpendicular to the fifth line IL5.

[0161] In the example of FIG. 19, the convex portion 33p (top portion 33pt) is not aligned with the convex portion 34p (top portion 34pt) in the second direction D2. The concave portion 33q (top portion 33qt) is not aligned with the concave portion 34q (top portion 34qt) in the second direction D2. That is, the width of the second flow path portion 312 changes along the first direction. This, for example, disrupts the flow of the refrigerant in the second flow path portion 312, thereby improving the cooling effect. However, the convex portion 33p (top portion 33pt) may be aligned with the convex portion 34p (top portion 34pt) in the second direction D2. Furthermore, the concave portion 33q (top portion 33qt) may be aligned with the concave portion 34q (top portion 34qt) in the second direction D2.

[0162] As described above, according to the embodiment, an electrostatic chuck is provided that can suppress the influence of misalignment of the coolant flow path, thereby improving the uniformity of the temperature distribution within the surface of the processing object.

[0163] The above describes the embodiments of the present invention. However, the present invention is not limited to these descriptions. Design modifications made by a person skilled in the art to the above-described embodiments are also included within the scope of the present invention as long as they include the features of the present invention. For example, the shape, dimensions, materials, arrangement, installation form, etc. of each element of the electrostatic chuck are not limited to those exemplified and can be modified as appropriate.

[0164] Furthermore, the elements of each of the above-described embodiments can be combined to the extent technically possible, and such combinations are also included within the scope of the present invention as long as they include the features of the present invention. [Explanation of symbols]

[0165] 10-12 electrostatic chuck, 31 first side surface, 31p convex portion, 31pa first convex portion, 31pb, 31pc convex portion, 31pt top portion, 31q concave portion, 31qa first concave portion, 31qb, 31qc concave portion, 31qt top portion, 32 second side surface, 32p convex portion, 32pt top portion, 32q concave portion, 32qt top portion, 33 third side surface, 33p convex portion, 33pa second convex portion, 33pt top portion, 33q concave portion, 33qa second concave portion, 33qt top portion, 34 fourth side surface, 34p convex portion, 34pt top portion, 34q concave portion, 34qt top portion, α, β points, θ angle, 100 Ceramic dielectric substrate, 101 first main surface, 102 second main surface, 111 electrode layer, 113 convex portion, 115 groove, 200 heater portion, 230 heater element, 230a first heater element, 230b second heater element, 231 to 239 first to ninth heater lines, 300 base plate, 300a upper member, 300af lower surface, 300b lower member, 300bf upper surface, 300c center, 300e outer periphery, 300g groove, 301 communicating path, 301c one end, 301d other end, 301g lower surface, 301s side surface, 301u upper surface, 302 upper surface, 303 lower surface, 311 First flow path portion, 311a first portion, 311b second portion, 312 second flow path portion, 312a third portion, 312b fourth portion, 321 introduction path, 332 flow path portion, 403 adhesive layer, B1 region, CR central region, Dα, Dβ directions, D1-D3 first to third directions, D31p, D31q, D33p, D33q directions, DR1 first refrigerant direction, DR2 second refrigerant direction, IC1-IC6 first to sixth imaginary circles, IL1-IL6 first to sixth straight lines, L, Lβ line segment, L1-L8, La, Lb distance, Ly straight line, R1-R4 first to fourth radial lines, Ra, Rb, Rc region, Rc1, Rc2 portion, V1-V4 first to fourth vertical lines, W Processing object, d distance, p1~p8 points, q1, q2 first and second sides,

Claims

1. a ceramic dielectric substrate having a mounting surface on which an object to be processed is placed; a base plate supporting the ceramic dielectric substrate and having an upper surface facing the ceramic dielectric substrate and a lower surface opposite to the upper surface; Equipped with the base plate includes a communication passage provided between the upper surface and the lower surface and through which a refrigerant can pass, the communication passage includes a first flow path portion having a pair of side surfaces along a first direction along the flow of the refrigerant, When viewed along the lamination direction of the base plate and the ceramic dielectric substrate, one of the pair of side surfaces has a plurality of protrusions that are protruded in a second direction perpendicular to the first direction and extending from the other side surface of the pair of side surfaces to the one side surface; a plurality of recesses that are convex in a direction opposite to the second direction; and the plurality of convex portions and the plurality of concave portions are arranged alternately, a heater unit provided inside the ceramic dielectric substrate or between the ceramic dielectric substrate and the base plate, the heater unit heating the ceramic dielectric substrate; the heater section includes a heater line, the heater line has a pair of sides extending in the same direction as the first direction, An electrostatic chuck, wherein at least a portion of one of the pair of sides overlaps with the first flow path portion in the stacking direction.

2. When viewed along the stacking direction, the other side surface of the pair of side surfaces is a plurality of protrusions protruding in the second direction; a plurality of recesses that are convex in a direction opposite to the second direction; and 2. The electrostatic chuck according to claim 1, wherein the plurality of convex portions on the other side surface and the plurality of concave portions on the other side surface are arranged alternately.

3. the first direction is a circumferential direction of the base plate, the plurality of protrusions on the one side surface include a first protrusion, the plurality of recesses on the one side surface include a first recess adjacent to the first protrusion, 3. The electrostatic chuck according to claim 1, wherein when a virtual circle that is in contact with the first convex portion and has its center at the center of the base plate is defined as a first virtual circle, and a virtual circle that is in contact with the first concave portion and has its center at the center of the base plate is defined as a second virtual circle, a first distance between the first virtual circle and the second virtual circle is longer than the shortest distance between the one side surface and the other side surface.

4. 4. The electrostatic chuck of claim 3, wherein the first distance is greater than or equal to 5 millimeters.

5. the first direction is a circumferential direction of the base plate, the plurality of protrusions on the one side surface include a first protrusion, the plurality of recesses on the one side surface include a first recess adjacent to the first protrusion, 5. The electrostatic chuck according to claim 1, wherein a first imaginary circle is a virtual circle that is tangent to the first convex portion and has its center at the center of the base plate, a second imaginary circle is a virtual circle that is tangent to the first concave portion and has its center at the center of the base plate, a third imaginary circle is a virtual circle that is equal to the distance from the first imaginary circle and the distance from the second imaginary circle, a first radial line is a straight line that connects the first convex portion and the center of the base plate, and a second radial line is a straight line that connects the first concave portion and the center of the base plate, a second radial line is a second radial line, and a second distance along the circumferential direction between an intersection of the first radial line and the third imaginary circle and an intersection of the second radial line and the third imaginary circle is 30 millimeters or more and 140 millimeters or less.

6. the first direction is a circumferential direction of the base plate, 6. The electrostatic chuck according to claim 1, wherein the one side surface is located closer to the outer periphery of the base plate than the other side surface.

7. the communication passage includes a second flow path portion having a pair of side surfaces aligned in a radial direction of the base plate, one of the pair of side surfaces of the second flow path portion has, when viewed along the stacking direction, a plurality of convex portions convex in the second direction and a plurality of concave portions convex in a direction opposite to the second direction, the plurality of convex portions of the second flow path portion and the plurality of concave portions of the second flow path portion are arranged alternately, the second flow path portion is located closer to the inner periphery of the base plate than the first flow path portion, the plurality of protrusions of the second flow path section include a second protrusion, the plurality of recesses of the second flow path portion include a second recess; 5. The electrostatic chuck according to claim 3, wherein a virtual circle that is in contact with the second convex portion and has its center at the center of the base plate is defined as a fourth virtual circle, and a virtual circle that is in contact with the second concave portion and has its center at the center of the base plate is defined as a fifth virtual circle. When the distance between the fourth virtual circle and the fifth virtual circle is defined as a third distance, the first distance is longer than the third distance.

8. the communication passage includes a second flow path portion having a pair of side surfaces aligned in a radial direction of the base plate, one of the pair of side surfaces of the second flow path portion has, when viewed along the stacking direction, a plurality of convex portions convex in the second direction and a plurality of concave portions convex in a direction opposite to the second direction, the plurality of convex portions of the second flow path portion and the plurality of concave portions of the second flow path portion are arranged alternately, the second flow path portion is located closer to the inner periphery of the base plate than the first flow path portion, the plurality of protrusions of the second flow path section include a second protrusion, the plurality of recesses of the second flow path portion include a second recess; 6. The electrostatic chuck of claim 5, wherein a virtual circle that is tangent to the second convex portion and has its center at the center of the base plate is defined as a fourth virtual circle, a virtual circle that is tangent to the first concave portion and has its center at the center of the base plate is defined as a fifth virtual circle, a virtual circle that is equal to a distance from the fourth virtual circle is defined as a sixth virtual circle, a straight line that connects the second convex portion and the center of the base plate is defined as a third radial line, and a straight line that connects the second concave portion and the center of the base plate is defined as a fourth radial line. In this case, a distance along the circumferential direction between an intersection of the third radial line and the sixth virtual circle and an intersection of the fourth radial line and the sixth virtual circle is defined as a fourth distance, wherein the second distance is shorter than the fourth distance.

9. the first direction is a linear direction, the plurality of protrusions on the one side surface include a first protrusion, the plurality of recesses on the one side surface include a first recess adjacent to the first protrusion, 3. The electrostatic chuck according to claim 1, wherein when a straight line tangent to the first convex portion and extending in the first direction is defined as a first straight line, and a straight line tangent to the first concave portion and extending in the first direction is defined as a second straight line, a fifth distance between the first straight line and the second straight line is longer than the shortest distance between the one side surface and the other side surface.

10. 10. The electrostatic chuck of claim 9, wherein the fifth distance is greater than or equal to 5 millimeters.

11. the first direction is a linear direction, the plurality of protrusions on the one side surface include a first protrusion, the plurality of recesses on the one side surface include a first recess adjacent to the first protrusion, 3. The electrostatic chuck according to claim 1, wherein a first line is a line tangent to the first convex portion and extending in the first direction, a second line is a line tangent to the first concave portion and extending in the first direction, a third line is a line that is equal to the distance from the first line and the distance from the second line, a first vertical line is a line that passes through the first convex portion and is perpendicular to the first line, and a second vertical line is a line that passes through the first concave portion and is perpendicular to the second line, a sixth distance between an intersection of the first vertical line and the third line and an intersection of the second vertical line and the third line is 30 millimeters or more and 140 millimeters or less.

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