Holding device

Abstract

A technique is provided for improving the temperature distribution on the mounting surface of a plate-like member in a holding device. [Solution] The holding device comprises a plate-shaped member having a pair of main surfaces, the plate-shaped member having a support surface formed on one of the pair of main surfaces on which an object is placed, a flow path disposed inside the plate-shaped member through which a refrigerant flows, and a hole formed along a direction intersecting each of the pair of main surfaces, the flow path having a branching and junction portion including a branching portion that branches the flow path into two branching flow paths, and a junction portion that joins the two branching flow paths branched by the branching portion into one, and there is no hole between the two branching flow paths.

Description

[Technical Field]

[0001] The present invention relates to a retaining device. [Background technology]

[0002] BACKGROUND ART Conventionally, a holding device is known that includes a plate-like member having a mounting surface on which an object is placed and a flow path through which a refrigerant flows (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 711460 [Patent Document 2] International Publication No. 2023 / 166866 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even with the prior art such as that of Patent Document 1, there is still room for improvement in the technology for improving the temperature distribution on the mounting surface of the plate-like member in the holding device.

[0005] An object of the present invention is to provide a technique for improving the temperature distribution on the mounting surface of a plate-like member in a holding device. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following aspects.

[0007] (1) According to one aspect of the present invention, there is provided a holding device comprising a plate-shaped member having a pair of main surfaces, the plate-shaped member having a mounting surface formed on one of the pair of main surfaces and on which an object is placed, a flow path disposed inside the plate-shaped member through which a refrigerant flows, and holes formed along a direction intersecting each of the pair of main surfaces, the flow path including a branching portion that branches the flow path into two branching flow paths and a merging portion that merges the two branching flow paths branched by the branching portion into one, and the hole is not between the two branching flow paths.

[0008] According to this configuration, the flow path of the plate-shaped member through which the coolant flows includes a branching section that branches the flow path into two branching flow paths and a merging section that merges the two branching flow paths into one. As a result, the coolant flowing through one flow path branches into two branching flow paths, then merges and flows back into a single flow path, which allows for a larger cooling range than, for example, when the coolant flows through only one flow path. Therefore, the degree of cooling at each part of the plate-shaped member can be adjusted, thereby improving the temperature distribution on the mounting surface of the plate-shaped member.

[0009] (2) In the holding device of the above embodiment, the flow path may have a plurality of the branching and merging portions. With this configuration, the number of branching and merging portions can be increased or decreased using information about the temperature distribution of the plate-like member obtained, for example, by simulation or experiment. Therefore, the temperature distribution on the mounting surface of the plate-like member can be further improved.

[0010] (3) In the holding device of the above embodiment, in a cross section perpendicular to the central axis of the plate-like member, including the flow paths, the distance between the two branch flow paths included in a first branch-junction among the plurality of branch-junctions may be greater than the distance between the two branch flow paths included in a second branch-junction among the plurality of branch-junctions. According to this configuration, the distance between the two branch flow paths included in each of the first branch-junction and the second branch-junction among the plurality of branch-junctions is different. This makes it possible, for example, to use information about the temperature distribution of the plate-like member to vary the distance between the two branch flow paths and adjust the degree of cooling at each portion of the plate-like member. This further improves the temperature distribution on the support surface of the plate-like member.

[0011] (4) In the holding device of the above aspect, in a cross section perpendicular to the central axis of the plate-like member and including the flow path, the two branch flow paths may be curved in directions away from each other. According to this configuration, the two branch flow paths included in the branching and merging section are curved in directions away from each other. This further increases the range over which the degree of cooling by the refrigerant is relatively high, thereby further improving the temperature distribution on the mounting surface of the plate-like member.

[0012] (5) In the holding device of the above embodiment, in a cross section perpendicular to the central axis of the plate-like member and including the flow path, one of the two branch flow paths may be formed to follow the shape of the flow path, and the other of the two branch flow paths may be formed to curve in a direction away from the one branch flow path. According to this configuration, one of the two branch flow paths included in the branch-and-junction section is formed to follow the shape of the flow path, while the other of the two branch flow paths is formed to curve in a direction away from the one branch flow path. This allows an area cooled by a relatively small amount of refrigerant flowing through one branch flow path to be added to an area cooled by a relatively large amount of refrigerant flowing through the other branch flow path. This increases the degree of freedom in adjusting the degree of cooling at each part of the plate-like member, thereby further improving the temperature distribution on the mounting surface of the plate-like member.

[0013] (6) In the holding device of the above embodiment, the width of the one branch flow path may be larger than the width of the other branch flow path. With this configuration, a smaller amount of refrigerant flows through the other branch flow path than through the one branch flow path. This allows the other branch flow path to have, for example, a relatively large curvature, allowing the refrigerant to flow even in places where it is difficult to form a branch flow path. Therefore, the area cooled by the refrigerant to a relatively large degree can be further increased, thereby further improving the temperature distribution on the mounting surface of the plate-like member.

[0014] (7) In the holding device of the above aspect, in a cross section perpendicular to the central axis of the plate-like member including the flow channels, a first branching / junction section among the plurality of branching / junction sections may be formed so that the two branching / junction sections curve in directions away from each other, and a second branching / junction section among the plurality of branching / junction sections may be formed so that one of the two branching / junction sections follows the shape of the flow channel and the other of the two branching / junction sections curves in a direction away from the one branching / junction, and the second branching / junction section may be disposed closer to the outer periphery of the plate-like member than the first branching / junction section. With this configuration, the other branching / junction section included in the second branching / junction section can be formed even in a location where it is difficult to form the two branching / junction sections included in the first branching / junction section. This allows the second branching / junction section to be disposed closer to the outer periphery of the plate-like member, where there are often restrictions on the formation of flow channels due to, for example, the shape of the plate-like member or the positions of holes formed in the base. Therefore, even locations where it is relatively difficult to form flow paths can be included in the range where the degree of cooling by the refrigerant is relatively high, which further improves the temperature distribution on the mounting surface of the plate-like member.

[0015] (8) In the holding device of the above embodiment, in a cross section perpendicular to the central axis of the plate-like member and including the flow path, the width of one of the two branch flow paths included in the branching and merging section may be larger than the width of the other of the two branch flow paths. With this configuration, a smaller amount of refrigerant flows through the other branch flow path than through one of the branch flow paths. In this way, the flow rate of the refrigerant can be adjusted by changing the width of the branch flow path, and the degree of cooling by the refrigerant on the plate-like member can be locally changed. This further improves the temperature distribution on the mounting surface of the plate-like member.

[0016] (9) In the holding device of the above embodiment, the branching and merging section may be disposed on the outer periphery of the plate-shaped member. According to this configuration, the branching and merging section is disposed on the outer periphery of the plate-shaped member, where there are often restrictions on the formation of flow paths. As a result, when an object is placed on the mounting surface, the outer periphery of the plate-shaped member, which corresponds to the outer periphery of the object that tends to become relatively hot, can be cooled by the refrigerant flowing through the branching and merging section. Therefore, the temperature distribution of the object can be controlled.

[0017] The present invention can be realized in various forms, such as a method for manufacturing a holding device, a system including a holding device, a control method for these devices and systems, a computer program for causing these devices and systems to process objects, a server device for distributing the computer program, and a non-transitory storage medium on which the computer program is stored. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a perspective view of the holding device of the first embodiment. [Figure 2] FIG. 2 is a first cross-sectional view of the holding device of the first embodiment. [Figure 3] FIG. 4 is a second cross-sectional view of the holding device of the first embodiment. [Figure 4] FIG. 4 is an enlarged view of part B in FIG. 3. [Figure 5] FIG. 10 is a diagram illustrating a method for creating a center line of a flow path. [Figure 6] FIG. 4 is an enlarged view of part C in FIG. 3. [Figure 7] FIG. 4 is an enlarged view of part D in FIG. 3. [Figure 8] FIG. 4 is an enlarged view of part E in FIG. 3. [Figure 9] FIG. 10 is a cross-sectional view of a holding device according to a second embodiment. [Figure 10] FIG. 10 is an enlarged view of part F in FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0019] First Embodiment FIG. 1 is a perspective view of a holding device 1 according to this embodiment. FIG. 2 is a first cross-sectional view of the holding device 1 according to this embodiment. The holding device 1 according to this embodiment is an electrostatic chuck that attracts and holds a substrate W by electrostatic attraction. The electrostatic chuck is used, for example, as a table on which the substrate W is placed in an etching process using plasma in a chamber equipped with the electrostatic chuck. The holding device 1 according to this embodiment includes a base 10, a ceramic substrate 20, and a joint (not shown). In the holding device 1, as shown in FIG. 1, the base 10 and the ceramic substrate 20 are stacked in this order. The holding device 1 positions the substrate W relative to the holding device 1 using a focus ring FR installed on the outer periphery of the ceramic substrate 20. For convenience, in FIGS. 1 and 2, the stacking direction of the base 10 and the ceramic substrate 20 is indicated as the z-axis direction, the direction perpendicular to the z-axis is indicated as the x-axis direction, and the direction perpendicular to the z-axis and the x-axis is indicated as the y-axis direction. For convenience of explanation, the dimensional relationships between the base 10, the ceramic base 20, the substrate W, and the focus ring FR in FIGS. 1 and 2 are different from the actual relationships.

[0020] The base 10 is a sintered body mainly composed of silicon carbide (SiC), and is a substantially cylindrical member that serves as the base of the holding device 1. Here, "main component" refers to the component with the highest content. The material forming the base 10 is not limited to a material mainly composed of silicon carbide. The base 10 may also be formed from aluminum (Al), titanium (Ti), molybdenum (Mo), tungsten (W), alloys thereof, SUS, composites of metals and ceramics such as Al-SiC, or materials mainly composed of ceramics such as aluminum nitride (AlN) or alumina (Al2O3).

[0021] The base 10 has a first base 11 and a second base 12. The first base 11 and the second base 12 are bonded together by an adhesive layer (not shown). Note that the base 10 is not limited to a two-layer structure such as the first base 11 and the second base 12, and may have a single-layer structure or a three or more layer structure.

[0022] 2, the first base 11 is located on the most negative side in the z-axis direction in the holding device 1. The first base 11 is a substantially circular plate-like member and has a pair of main surfaces 11a, 11b. On one main surface 11a of the pair of main surfaces 11a, 11b of the first base 11, an inlet (not shown) through which a refrigerant flowing through a flow path 30 (described later) flows into the flow path 30 and an outlet (not shown) through which the refrigerant flows out of the flow path 30 are formed.

[0023] The second base 12 is stacked on the first base 11 on the positive side of the first base 11 in the z-axis direction. The second base 12 is a substantially circular plate-like member having approximately the same size as the first base 11 and has a pair of main surfaces 12a and 12b. Of the pair of main surfaces 12a and 12b of the second base 12, the main surface 12b on the negative side in the z-axis direction has a groove 13 formed therein to serve as a flow path 30 through which the refrigerant flows. When the first base 11 and the second base 12 are joined together, the first base 11 serves as a cover for the groove 13, thereby forming the flow path 30. The base 10 has a plurality of holes 14 formed along the z-axis direction of the holding device 1. The detailed shape of the flow path 30 will be described later.

[0024] The ceramic substrate 20 is a plate-shaped member disposed on the positive side of the base 10 in the z-axis direction. The ceramic substrate 20 is mainly composed of ceramic. The ceramic substrate 20 of this embodiment is formed from a material mainly composed of aluminum oxide. The ceramic substrate 20 may also be formed from other ceramics such as aluminum nitride or silicon carbide. The ceramic substrate 20 has a pair of main surfaces 20a and 20b.

[0025] The ceramic base 20 has a pair of main surfaces 20a, 20b, and a mounting surface 21 on which a substrate W is mounted is formed on one main surface 20a opposite the base 10. A focus ring mounting surface 22 on which a focus ring FR is mounted is formed on the outer periphery of the one main surface 20a of the ceramic base 20. The other main surface 20b of the pair of main surfaces 20a, 20b of the ceramic base 20 is joined to the second base 12 by a joint (not shown). The ceramic base 20 has holes 23 formed therein that communicate with the plurality of holes 14 formed in the base 10. Note that the method for joining the base 10 and the ceramic base 20 includes, but is not limited to, metal joining, resin joining, and joining using an inorganic material.

[0026] The ceramic base 20 of this embodiment has an electrode 24. The electrode 24 is disposed inside the ceramic base 20. The electrode 24 is formed of a conductive material such as tungsten or molybdenum. The electrode 24 is connected to an external power supply via an electrode terminal (not shown) inserted through the holes 14 and 23. Examples of the electrode 24 include a high-frequency electrode, a chuck electrode, and a heater electrode.

[0027] The holding device 1 of this embodiment has a hole 5a penetrating the bonded body 5 made of the base 10 and the ceramic substrate 20 in the z-axis direction by the hole 14 formed in the base 10 and the hole 23 formed in the ceramic substrate 20. The hole 5a in the bonded body 5 is used as a terminal hole for inserting a power supply terminal (not shown) for supplying power to the electrode 24 of the ceramic substrate 20, a gas hole for supplying helium gas to the backside of the substrate W, a lift pin hole for inserting a lift pin (not shown) for lifting the substrate W from the ceramic substrate 20, a sensor hole for inserting a temperature sensor (not shown) for measuring the temperature of the mounting surface 21, and the like. Note that although the hole 5a in the bonded body 5 of this embodiment is described as penetrating the bonded body 5 in the z-axis direction, it does not have to penetrate the bonded body 5. Specifically, the hole 5a may be configured by combining, for example, the hole 14 penetrating the base 10 with the other main surface 20b of the ceramic substrate 20 or a hole having a bottom surface formed on the other main surface 20b. In this case, the other main surface 20b of the ceramic base 20 or a bottom surface formed on the other main surface 20b serves as the bottom surface of the hole 5a. Alternatively, the hole 14 may be a non-through hole having a bottom surface. The bonded body 5 corresponds to a "plate-like member" in the claims.

[0028] Next, the detailed shape of the flow path 30 will be described. The flow path 30 has a plurality of branching and merging sections 31, 32. Each of the plurality of branching and merging sections 31, 32 has a branching section that branches the flow path 30 into two branching flow paths, and a merging section that merges the two branching flow paths branched by the branching section into one. In the holding device 1 of this embodiment, there is no hole 14 between the two branching flow paths included in each of the plurality of branching and merging sections 31, 32.

[0029] 3 is a second cross-sectional view of the holding device 1. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2, specifically, a cross-sectional view perpendicular to the central axis C5 of the bonded body 5 at the second base 12 in which the groove 13 is formed. The flow path 30 of this embodiment is formed in a substantially spiral shape as shown in FIG. 3. The flow path 30 has a flow path inlet 30a through which the refrigerant from the outside flows into the flow path 30, and a flow path outlet 30b through which the refrigerant that has flowed through the flow path 30 flows out of the flow path 30. That is, in the holding device 1 of this embodiment, the refrigerant flows into the flow path 30 from near the central axis C5 of the bonded body 5, flows counterclockwise toward the outer periphery of the base 10, and is discharged to the outside of the base 10 from the flow path outlet 30b.

[0030] Fig. 4 is an enlarged view of part B in Fig. 3, and is an enlarged cross-sectional view including branching and merging portion 31 of the plurality of branching and merging portions 31, 32. Branching and merging portion 31 shown in Fig. 4 has branching portion 313 that branches flow path 30 into two branching flow paths 311, 312, and merging portion 314 that merges the two branching flow paths 311, 312 branched by branching portion 313 into one. In branching and merging portion 31, as shown in Fig. 4, no hole 14 is formed in island-shaped portion 315 sandwiched between the two branching flow paths 311, 312.

[0031] The branching and merging portion 31 is formed such that two branching channels 311, 312 are curved away from each other in a cross section perpendicular to the central axis C5 of the assembly 5 including the channel 30 as shown in Fig. 4. Specifically, using the center line C30 of the channel 30 shown in Fig. 4, each of the branching channels 311, 312 is formed so as not to include the center line C30 of the channel 30. The branching channel 311 is formed so as to bulge inward from the assembly 5 toward the central axis C5 of the assembly 5 as viewed from the center line C30 of the channel 30. The branching channel 312 is formed so as to bulge outward from the assembly 5 in a direction away from the central axis C5 of the assembly 5 as viewed from the center line C30 of the channel 30. As a result, the island-shaped portion 315 sandwiched between the two branch flow paths 311, 312 becomes a portion that is cooled to a relatively large extent by the refrigerant flowing through each of the branch flow paths 311, 312, and therefore the range that is cooled to a relatively large extent by the refrigerant can be increased.

[0032] FIG. 5 is a diagram illustrating a method for creating a center line of a flow channel. Here, the method for creating a center line of a flow channel in this embodiment will be described. In the method for creating a center line of a flow channel in this embodiment, first, multiple imaginary lines passing through points on the central axis are created in a cross section perpendicular to the central axis of a member in which the flow channel is formed. Specifically, as shown in FIG. 5, multiple imaginary lines L1, L2, L3, L4, L5, L6, and L7 passing through points on the central axis C5 are created in a cross section perpendicular to the central axis C5 of a bonded body 5 having a substantially circular shape. The multiple imaginary lines L1, L2, L3, L4, L5, L6, and L7 can be created at regular intervals by, for example, setting the angles of adjacent imaginary lines L1, L2, L3, L4, L5, L6, and L7 to differ by 1 degree on the central axis C5. Note that if the cross section of the member in which the flow channel is formed is polygonal, multiple imaginary lines may be created with a line passing through the center of gravity of the polygon as the central axis.

[0033] Next, in a cross section perpendicular to the central axis of the component on which the flow paths are formed, intersections between the imaginary line and the outline of the flow path are determined. Specifically, as shown in FIG. 5, for example, intersections P1a and P1b are determined as the intersections of the imaginary line L1 and the outline of the flow path 30. When the imaginary line intersects each of two branch flow paths, the intersections closest to the central axis and the intersections farthest from the central axis are determined as the intersections between the imaginary line and the outline of the flow path. Specifically, in the case of the imaginary line L3 shown in FIG. 5, the intersection of the branch flow path 311, 312, which is closer to the central axis C5, with the outline Li311 on the opposite side of the branch flow path 312 is determined as intersection P3a, and the intersection of the branch flow path 312, which is farther from the central axis C5, with the outline Lo312 on the opposite side of the branch flow path 311 is determined as intersection P3b. Such determination of intersections is performed for each of the imaginary straight lines L1, L2, L3, L4, L5, L6, and L7 that pass through the area including the branching and merging section 31, and intersections P1a and P1b on the imaginary straight line L1, intersections P2a and P2b on the imaginary straight line L2, intersections P3a and P3b on the imaginary straight line L3, intersections P4a and P4b on the imaginary straight line L4, intersections P5a and P5b on the imaginary straight line L5, intersections P6a and P6b on the imaginary straight line L6, and intersections P7a and Pb on the imaginary straight line L7 are determined.

[0034] Next, the midpoint between two intersections on one imaginary line is determined. Specifically, in the case of imaginary line L1 shown in FIG. 5, a point on imaginary line L1 that is the same distance from intersections Pa1 and Pa2 is determined as midpoint P1m. Midpoints P2m, P3m, P4m, P5m, P6m, and P7m are determined for imaginary lines L2, L3, L4, L5, L6, and L7 in a similar manner. Finally, the center line of the flow path is determined by connecting multiple midpoints. In FIG. 5, the two-dot chain line connecting midpoints P1m, P2m, P3m, P4m, P5m, P6m, and P7m is the center line C30 of flow path 30. In the explanation using FIG. 5, to avoid cluttering the drawing, virtual straight lines L1, L2, L3, L4, L5, L6, and L7 are set at certain intervals to discretely determine intermediate points P1m, P2m, P3m, P4m, P5m, P6m, and P7m. Therefore, the shape of the center line C30 between adjacent intermediate points is such that the intermediate points P1m, P2m, P3m, P4m, P5m, P6m, and P7m are smoothly connected. However, the method of connecting the intermediate points is not limited to this. Adjacent intermediate points may be connected by a straight line. Furthermore, adjacent intermediate points may be continuously determined by reducing the angle between the central axes of adjacent virtual straight lines, and adjacent intermediate points may be connected. The method of creating the center line of the flow path is not limited to this.

[0035] In the branching and merging section 31, in a cross section perpendicular to the central axis C5 of the assembly 5, the width of the branching and merging section 312 of the two branching channels 311 and 312 included in the branching and merging section 31 is larger than the width of the branching and merging section 311 of the two branching channels 311 and 312. In this manner, the widths of the two branching channels 311 and 312 in the branching and merging section 31 can be made different. This makes it possible to adjust the flow of the refrigerant and change the degree of cooling by the refrigerant. Note that the width of the branching and merging section 311 and the width of the branching and merging section 312 may be the same.

[0036] 6 is an enlarged view of portion C in FIG. 3, and is an enlarged cross-sectional view including branching and merging portion 32 of the multiple branching and merging portions 31 and 32. Branching and merging portion 32 shown in FIG. 6 has branching portion 323 that branches flow path 30 into two branching flow paths 321 and 322, and merging portion 324 that merges the two branching flow paths 321 and 322 branched by branching portion 323 into one. In branching and merging portion 32, as shown in FIG. 6, no hole 14 is formed in island-shaped portion 325 sandwiched between the two branching flow paths 321 and 322. Branching flow path 321 corresponds to "one branching flow path" in the claims, and branching flow path 322 corresponds to "the other branching flow path" in the claims.

[0037] In the branching and merging portion 32, in a cross section perpendicular to the central axis C5 of the assembly 5 including the flow channel 30 as shown in FIG. 6 , the branching and merging portion 32 has two branching flow channels 321, 322, of which the branching flow channel 321 is formed to follow the shape of the flow channel 30, and the branching flow channel 322 is formed to curve in a direction away from the branching flow channel 321. Specifically, the branching flow channel 321 is formed to be more linear than the branching flow channel 322 and has a shape with a smaller degree of curvature than the branching flow channel 322. More specifically, using the center line C30 of the flow channel 30 shown in FIG. 6 as an example, the branching flow channel 321 is formed to include the center line C30 of the flow channel 30. On the other hand, the branching flow channel 322 is formed so as not to include the center line C30 of the flow channel 30 and to bulge outward from the assembly 5 in a direction away from the central axis C5 of the assembly 5 as viewed from the center line C30 of the flow channel 30. Furthermore, branch flow path 321 has a shape that gently connects flow path 30 upstream of branch portion 323 with flow path 30 downstream of junction portion 324. Meanwhile, branch flow path 322 is formed such that the distance to center line C30 increases with increasing distance from branch portion 323 and decreases with increasing distance to junction portion 324. Island-shaped portion 325 sandwiched between branch flow path 321 and branch flow path 322 having such a shape is a portion that is cooled to a relatively large extent by the refrigerant flowing through each of branch flow paths 321 and 322, and therefore the range that is cooled to a relatively large extent by the refrigerant can be enlarged.

[0038] In the branching and merging section 32 shown in FIG. 6 , the width of the branching channel 321, which is formed to follow the shape of the channel 30, is larger than the width of the branching channel 322. As a result, most of the refrigerant flowing through the channel 30 flows through the branching channel 321, and a relatively small amount of refrigerant flows through the branching channel 322. Therefore, even if the branching channel 322 has a small curvature, the pressure loss of the refrigerant flow in the channel 30 is not large. Therefore, the branching and merging section 32, including the branching channel 322, is easily arranged on the outer periphery of the bonded body 5, where the formation of the channel 30 is often constrained by the shape of the base 10 and the position of the hole 14 formed in the base 10. Furthermore, the orientation flat of the substrate W placed on the mounting surface 21 is located outside the bonded body 5. The orientation flat of the substrate W is often not in contact with the ceramic base 20, and therefore is prone to temperature rise. However, by arranging the branching and merging section 32, including the branching channel 322, on the outer periphery of the bonded body 5, the orientation flat of the substrate W can be efficiently cooled. Because the branching and merging section 32 has these characteristics, of the multiple branching and merging sections 31, 32, most of the branching and merging sections 32 are positioned closer to the outer periphery of the holding device 1 than the branching and merging section 31 (see Figure 3).

[0039] The holding device 1 of this embodiment has a plurality of branching and merging sections 31 and a plurality of branching and merging sections 32. In a cross section perpendicular to the central axis C5 of the bonded body 5, including the flow path 30, as shown in FIG. 3 , the distance between the two branching flow paths 311, 312 included in a first branching and merging section 31 of the plurality of branching and merging sections 31 is greater than the distance between the two branching flow paths 311, 312 included in a second branching and merging section 31 of the plurality of branching and merging sections 31. The distance between the two branching flow paths 321, 322 included in a first branching and merging section 32 of the plurality of branching and merging sections 32 is greater than the distance between the two branching flow paths 321, 322 included in a second branching and merging section 32 of the plurality of branching and merging sections 32.

[0040] Fig. 7 is an enlarged view of portion D in Fig. 3, and is an enlarged cross-sectional view including two branching and merging portions 31a and 31b out of the plurality of branching and merging portions 31 included in flow path 30. Fig. 7 shows center line C30 of flow path 30 described with reference to Fig. 5. As shown in Fig. 7, the size of island-shaped portion 315 sandwiched between two branching flow paths 311 and 312 included in branching and merging portion 31a is larger than the size of island-shaped portion 315 sandwiched between two branching flow paths 311 and 312 included in branching and merging portion 31b. Specifically, if the length of the longest line segment that is perpendicular to the center line C30 of the flow path 30 and connects the outline line Lo311 of the branch flow path 311 on the branch flow path 312 side and the outline line Li312 of the branch flow path 312 on the branch flow path 311 side is defined as the distance between the two branch flow paths 311, 312, then the distance L31a between the two branch flow paths 311, 312 included in the branch junction 31a is greater than the distance L31b between the two branch flow paths 311, 312 included in the branch junction 31b.

[0041] 8 is an enlarged view of a portion E in FIG. 3, and is an enlarged cross-sectional view including two branching and merging portions 32a and 32b among the multiple branching and merging portions 32 included in the flow path 30. FIG. 8 shows the center line C30 of the flow path 30 described with reference to FIG. 8. Note that FIG. 8 also shows the center line C30a of the flow path 30 at the branching and merging portion 32a and the center line C30b of the flow path 30 at the branching and merging portion 32b. As shown in FIG. 8, the size of the island-shaped portion 325 sandwiched between the two branching flow paths 321 and 322 included in the branching and merging portion 32a is smaller than the size of the island-shaped portion 325 sandwiched between the two branching flow paths 321 and 322 included in the branching and merging portion 32b. Specifically, for the branching and merging portion 32a, the length of the longest line segment that is perpendicular to the center line C30a of the flow channel 30 and that connects the outline line Lo321 of the branching channel 321 on the branching channel 322 side with the outline line Li322 of the branching channel 322 on the branching channel 321 side is defined as the distance L32a between the two branching channels 321 and 322. For the branching and merging portion 32b, the length of the longest line segment that is perpendicular to the center line C30b of the flow channel 30 and that connects the outline line Li321 of the branching channel 321 on the branching channel 322 side with the outline line Lo322 of the branching channel 322 on the branching channel 321 side is defined as the distance L32b between the two branching channels 321 and 322 at the branching and merging portion 32b. In this case, the distance L32a between the two branch flow paths 321 and 322 included in the branch-junction portion 32a is smaller than the distance L32b between the two branch flow paths 311 and 312 included in the branch-junction portion 32b.

[0042] 7 and 8, even in branching and merging units having similar configurations, the size of the range where the degree of cooling by the refrigerant is relatively high can be changed by varying the distance between two branching channels. Similarly, the relationship between the distance between two branching channels 311, 312 included in branching and merging unit 31 and the distance between two branching channels 321, 322 included in branching and merging unit 32 also varies, and the size of the range where the degree of cooling by the refrigerant is relatively high can be changed by varying the distance between the two branching channels.

[0043] According to the holding device 1 of the present embodiment described above, the flow path 30 of the bonded body 5 through which the refrigerant flows includes a branching and merging section 31 having a branching section 313 that branches the flow path 30 into two branching flow paths 311 and 312 and a merging section 314 that merges the two branching flow paths 311 and 312 branched by the branching section 313 into one, and a branching and merging section 32 having a branching section 323 that branches the flow path 30 into two branching flow paths 321 and 322 and a merging section 324 that merges the two branching flow paths 321 and 322 branched by the branching section 323 into one. As a result, the refrigerant flowing through one flow path 30 branches into two branching flow paths 311 and 312 or two branching flow paths 321 and 322 and then merges and flows again through one flow path 30. Therefore, the area to be cooled can be made larger than when the refrigerant flows through only one flow path, for example. Therefore, the degree of cooling at each portion of the bonded body 5 can be adjusted, and the temperature distribution on the mounting surface 21 of the bonded body 5 can be improved.

[0044] Furthermore, the holding device 1 of the present embodiment can adjust the degree of cooling on the mounting surface 21 of the bonded body 5. This can improve the uniformity of heat removal from the substrate W mounted on the mounting surface 21 in a process using plasma.

[0045] Furthermore, according to the holding device 1 of this embodiment, the number of branching and merging sections 31, 32 can be increased or decreased using information on the temperature distribution of the bonded body 5 obtained by, for example, simulation or experiment. Therefore, the temperature distribution on the mounting surface 21 of the bonded body 5 can be further improved.

[0046] Furthermore, according to the holding device 1 of this embodiment, the distance between the two branch channels 311, 312 included in the branch junction 31 of the multiple branch junctions 31, 32 is greater than the distance between the two branch channels 321, 322 included in the branch junction 32 of the multiple branch junctions 31, 32. This makes it possible to adjust the degree of cooling at each part of the bonded body 5 by varying the sizes of the branch junctions 31, 32 using information on the temperature distribution of the bonded body 5. This makes it possible to further improve the temperature distribution on the mounting surface 21 of the bonded body 5.

[0047] Furthermore, according to the holding device 1 of this embodiment, the two branch flow paths 311, 312 included in the branching and merging section 31 are curved in directions away from each other. This allows the range that is cooled by the refrigerant to be relatively large to be enlarged, thereby further improving the temperature distribution on the mounting surface 21 of the bonded body 5.

[0048] Furthermore, according to the holding device 1 of this embodiment, the branch flow path 321 of the two branch flow paths 321, 322 included in the branching and merging section 32 is formed to follow the shape of the flow path 30, while the branch flow path 322 of the two branch flow paths 321, 322 is formed to curve in a direction away from the branch flow path 321. This makes it possible to add a range cooled by a relatively small amount of refrigerant flowing through the branch flow path 322 to a range cooled by the refrigerant flowing through the branch flow path 321, through which a relatively large amount of refrigerant easily flows. Therefore, the degree of freedom in adjusting the degree of cooling at each part of the bonded body 5 is improved, and the temperature distribution on the mounting surface 21 of the bonded body 5 can be further improved.

[0049] Furthermore, according to the holding device 1 of this embodiment, at the branching and merging section 32, the width of the branch flow path 321 is larger than the width of the branch flow path 322, so that a smaller amount of refrigerant flows through the branch flow path 322 than through the branch flow path 321. As a result, by forming the branch flow path 322 in a shape with a relatively large curvature, i.e., a shape with a sharp curvature and a small curvature, the refrigerant can flow even in a place where it is difficult to form a branch flow path without increasing the pressure loss of the refrigerant. Therefore, the area cooled by the refrigerant to a relatively large degree can be further enlarged, and the temperature distribution on the mounting surface 21 of the bonded body 5 can be further improved.

[0050] Furthermore, according to the holding device 1 of this embodiment, the branch flow path 322 included in the branch-junction section 32 can be formed even in a location where it is difficult to form the two branch flow paths 311, 312 included in the branch-junction section 31. As a result, the branch-junction section 32 can be disposed on the outer periphery of the bonded body 5 relatively close to the orientation flat of the substrate W, which is often not in contact with the ceramic base 20, due to constraints on the formation of the flow path 30, such as the shape of the bonded body 5 and the position of the hole 14 formed in the base 10. In this way, even in a location where it is relatively difficult to form a flow path 30 and where the thermal environment is severe, the branch-junction section 32 can be formed to include the area in which the degree of cooling by the refrigerant is relatively high. This further improves the temperature distribution on the mounting surface 21 of the bonded body 5.

[0051] Furthermore, according to the holding device 1 of this embodiment, the branch flow path 312 included in the branching and merging section 31 has a narrower width than the branch flow path 311. As a result, a smaller amount of refrigerant flows through the branch flow path 312 than through the branch flow path 311. In this way, the flow rate of the refrigerant can be adjusted by changing the widths of the branch flow paths 311 and 312, and therefore the degree of cooling by the refrigerant can be locally changed in the bonded body 5. Therefore, the temperature distribution on the mounting surface 21 of the bonded body 5 can be further improved.

[0052] Furthermore, according to the holding device 1 of this embodiment, the branching and merging section 32 is disposed on the outer periphery of the bonded body 5, where there are often restrictions on the formation of the flow paths 30. As a result, when the substrate W is placed on the mounting surface 21, the outer periphery of the bonded body 5, which corresponds to the outer periphery of the substrate W that is likely to become relatively hot, can be cooled by the refrigerant flowing through the branching and merging section 32. Therefore, the temperature distribution of the substrate W can be controlled.

[0053] Second Embodiment 9 is a cross-sectional view of a holding device of the second embodiment. The holding device 2 of the second embodiment differs from the holding device 1 of the first embodiment (FIG. 3) in that the flow path has three types of branching and merging parts.

[0054] The holding device 2 of the second embodiment includes a base 10, a ceramic substrate 20, and a joint (not shown). The base 10 of the holding device 2 has a flow path 30 which has a plurality of branching and merging portions 31, 32, as well as a branching and merging portion 33.

[0055] 10 is an enlarged view of a portion F in FIG. 9. The branching and merging section 33 shown in FIG. 10 includes a branching section 333 that branches the flow path 30 into two branching flow paths 331 and 332, and a merging section 334 that merges the two branching flow paths 331 and 332 branched by the branching section 333 into one. The branching and merging section 33 is formed to connect to each of the two branching and merging sections 31, and the two branching flow paths 331 and 332 are formed to be approximately parallel, as shown in FIG. 10. As a result, the refrigerant that merges at the merging section 314 of the branching and merging section 31 flows through one of the two branching flow paths 331 and 332, thereby reducing the pressure loss of the refrigerant flowing through the flow path 30. An island-shaped portion 335 sandwiched between the two branching flow paths 331 and 332 included in the branching and merging section 33 does not have a hole 14.

[0056] According to the holding device 2 of this embodiment described above, the refrigerant flowing through one flow path 30 branches into two branch flow paths 311 and 312 or two branch flow paths 321 and 322, and then merges and flows again through one flow path 30, thereby making it possible to relatively increase the range of cooling. Therefore, the degree of cooling at each part of the bonded body 5 can be adjusted, and the temperature distribution on the mounting surface 21 of the bonded body 5 can be improved.

[0057] Furthermore, according to the holding device 2 of this embodiment, the branching and merging section 33 has two branching channels 331, 332 arranged approximately parallel to each other so that the refrigerant that merges at the junction 314 of the branching and merging section 31 located upstream of the branching and merging section 33 splits into two paths to flow even after the refrigerant has merged. This reduces pressure loss at the junction 314.

[0058] <Modification of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

[0059] [Variation 1] In the above-described embodiment, the flow path 30 has a plurality of branching and merging sections 31, 32. The number of branching and merging sections that the flow path of the holding device has is not limited to this. It may be one. Furthermore, the flow path 30 has the branching and merging section 31 and the branching and merging section 32, which have different configurations. The branching and merging section that the flow path 30 has may be either the branching and merging section 31 or the branching and merging section 32.

[0060] [Variation 2] In the above-described embodiment, the holes 14 and 23 formed in the holding device penetrate the holding device as shown in Fig. 2. However, the holes 14 and 23 do not have to penetrate the base 10.

[0061] [Variation 3] In the above-described embodiment, for each of the plurality of branching and merging sections included in the flow path 30 of the assembly 5, the island-shaped section sandwiched between the two branching flow paths does not have a hole. However, some of the plurality of branching and merging sections included in the flow path may have a hole in the island-shaped section. For example, a branching and merging section having a hole in the island-shaped section may be disposed on both sides of a branching and merging section having no hole in the island-shaped section. In the assembly, the hole portion is likely to become a temperature singularity point, so the flow path is formed to surround the hole. On the other hand, as in the above-described embodiment, even in a portion without a hole, the temperature distribution on the mounting surface of the assembly can be adjusted by dividing one flow path into two branching flow paths by the branching and merging section.

[0062] [Variation 4] In the above-described embodiment, the branching and merging section 31 is formed so that the two branching flow paths 311, 312 are curved in directions away from each other. The branching and merging section 32 is formed so that the branching flow path 321 of the two branching flow paths 321, 322 is formed so that it follows the shape of the flow path 30, and the branching flow path 322 is formed so that it curves in a direction away from the branching flow path 321. The configuration of the branching and merging section is not limited to this. For example, both of the branching flow paths may be formed so that they curve in the same direction. It is sufficient that the branching and merging section 31 has a branching section that branches the flow path 30 into two branching flow paths and a merging section that merges the two branching flow paths branched by the branching section into one.

[0063] [Variation 5] In the above-described embodiment, each of the two branch flow paths 311, 312 included in the branching and merging section 31 has a shape that does not include the center line C30 of the flow path 30 described with reference to FIG. 5. The branch flow path 321 included in the branching and merging section 32 has a shape that includes the center line C30 of the flow path 30, and the branch flow path 322 has a shape that does not include the center line C30 of the flow path 30. The relationship between each of the branch flow paths 311, 312, 321, 322 and the center line C30 of the flow path 30 is not limited to this. For example, the branch flow path 321 included in the branching and merging section 32 may have a shape that does not include the center line C30 of the flow path 30, and for example, the branch flow path 321 may be curved on the same side as the branch flow path 322 with respect to the center line C30 of the flow path 30.

[0064] [Variation 6] In the above-described embodiment, the branching and merging portion 32 is arranged closer to the outer periphery of the joined body 5 than the branching and merging portion 31. Also, the branching and merging portion 32 is arranged closer to the outer periphery of the joined body 5. The positional relationship between the branching and merging portion 31 and the branching and merging portion 32 in the joined body 5 is not limited to this.

[0065] [Variation 7] In the above-described embodiment, the holding device includes a base, a ceramic substrate, and a joint. However, the configuration of the holding device is not limited to this. The holding device may be a single plate-like member in which a portion corresponding to the base and a portion corresponding to the ceramic substrate are integrated. Alternatively, the portion corresponding to the joint may not be present, and the member corresponding to the base and the member corresponding to the ceramic substrate may be joined by diffusion bonding.

[0066] [Variation 8] In the above-described embodiment, the grooves 13 that serve as the flow paths 30 through which the refrigerant flows are formed in the principal surface 12b on the negative side in the z-axis direction of the pair of principal surfaces 12a, 12b of the second base 12 of the base 10. However, the position at which the flow paths 30 are formed in the base 10 is not limited thereto. For example, the grooves that serve as the flow paths 30 may be formed in the principal surface 12a on the positive side in the z-axis direction of the pair of principal surfaces 12a, 12b of the second base 12.

[0067] [Variation 9] In the above-described embodiment, the electrode 24 is disposed inside the ceramic base 20. The electrode 24 may be disposed on the base 10 or on a joint portion that joins the base 10 and the ceramic base 20.

[0068] This aspect has been described above based on embodiments and modifications. However, the above-described embodiments are intended to facilitate understanding of this aspect and are not intended to limit this aspect. This aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in this aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0069] <Application example 1> A holding device, a plate-like member having a pair of main surfaces, the plate-like member having a placement surface formed on one of the pair of main surfaces and on which an object is placed, a flow path disposed inside the plate-like member and through which a refrigerant flows, and holes formed along a direction intersecting each of the pair of main surfaces; the flow path includes a branching and merging section having a branching section that branches the flow path into two branch flow paths and a merging section that merges the two branch flow paths branched by the branching section into one, There is no hole between the two branch flow paths. holding device. <Application example 2> The holding device according to Application Example 1, The flow path has a plurality of the branching and merging portions. holding device. <Application example 3> The holding device according to Application Example 1 or Application Example 2, a distance between two of the branched flow paths included in a first branched-flow junction among the plurality of branched-flow junctions is greater than a distance between two of the branched flow paths included in a second branched-flow junction among the plurality of branched-flow junctions. holding device. <Application Example 4> The holding device according to any one of Application Examples 1 to 3, In a cross section perpendicular to the central axis of the plate-like member including the flow channel, The two branch flow paths are formed so as to curve in directions away from each other. holding device. <Application example 5> The holding device according to any one of Application Examples 1 to 4, In a cross section perpendicular to the central axis of the plate-like member including the flow channel, One of the two branch flow paths is formed to follow the shape of the flow path, The other of the two branch flow paths is formed so as to curve in a direction away from the one branch flow path. holding device. <Application Example 6> The holding device according to any one of Application Examples 1 to 5, The width of one of the branch flow paths is larger than the width of the other of the branch flow paths. holding device. <Application Example 7> The holding device according to any one of Application Examples 1 to 6, In a cross section perpendicular to the central axis of the plate-like member including the flow channel, a first branching and merging portion among the plurality of branching and merging portions is formed so that the two branching flow paths are curved in directions away from each other, A second branching and merging portion among the plurality of branching and merging portions includes: One of the two branch flow paths is formed to follow the shape of the flow path, the other of the two branch flow paths is formed so as to curve in a direction away from the one branch flow path, The second branching and merging portion is disposed closer to the outer periphery of the plate-like member than the first branching and merging portion. holding device. <Application Example 8> The holding device according to any one of Application Examples 1 to 7, In a cross section perpendicular to the central axis of the plate-like member including the flow channel, a width of one of the two branch flow paths included in the branch-and-junction section being larger than a width of the other of the two branch flow paths, holding device. <Application Example 9> The holding device according to any one of Application Examples 1 to 8, The branching and merging portion is disposed on the outer periphery of the plate-like member. holding device. [Explanation of symbols]

[0070] 1,2...holding device 5…Zygote 10...Foundation 11a, 11b...(First base) main surface 12a, 12b...(Main surface of second base) 14,23…holes 20...Ceramic substrate 21...Placement surface 30...Flow path 31, 31a, 31b, 32, 32a, 32b, 33... Branching and merging sections 311, 312, 321, 322, 331, 332...Branched flow paths 313, 323, 333... Branch 314, 324, 334...Confluence 315,325,335...island

Claims

1. A holding device, comprising: a plate-like member having a pair of main surfaces, the plate-like member having a placement surface formed on one of the pair of main surfaces and on which an object is placed, a flow path disposed inside the plate-like member and through which a coolant flows, and a hole formed along a direction intersecting each of the pair of main surfaces; the flow path has a branching and merging portion including a branching portion that branches the flow path into two branch flow paths, and a merging portion that merges the two branch flow paths branched by the branching portion into one, There is no hole between the two branch flow paths. holding device.

2. 2. The holding device according to claim 1, The flow path has a plurality of the branching and merging portions. holding device.

3. 3. The holding device according to claim 2, In a cross section perpendicular to the central axis of the plate-like member including the flow path, a distance between two of the branch flow paths included in a first branch junction among the plurality of branch junctions is greater than a distance between two of the branch flow paths included in a second branch junction among the plurality of branch junctions. holding device.

4. A holding device according to any one of claims 1 to 3, In a cross section perpendicular to the central axis of the plate-like member including the flow path, The two branch flow paths are formed so as to be curved in directions away from each other. holding device.

5. A holding device according to any one of claims 1 to 3, In a cross section perpendicular to the central axis of the plate-like member including the flow path, One of the two branch flow paths is formed to follow a shape of the flow path, The other of the two branch flow paths is formed so as to be curved in a direction away from the one of the branch flow paths. holding device.

6. A holding device according to claim 5. The width of the one branch flow path is larger than the width of the other branch flow path. holding device.

7. A holding device according to claim 2 or claim 3, In a cross section perpendicular to the central axis of the plate-like member including the flow path, a first branching / junction portion among the plurality of branching / junction portions is formed such that the two branched flow paths are curved in directions away from each other, A second branching / junction portion of the plurality of branching / junction portions includes: One of the two branch flow paths is formed to follow the shape of the flow path, the other of the two branch flow paths is formed so as to be curved in a direction away from the one of the branch flow paths, The second branching and merging portion is disposed on an outer periphery side of the plate-like member relative to the first branching and merging portion. holding device.

8. A holding device according to any one of claims 1 to 3. In a cross section perpendicular to the central axis of the plate-like member including the flow path, a width of one of the two branch flow paths included in the branch-junction portion is larger than a width of the other of the two branch flow paths, holding device.

9. A holding device according to any one of claims 1 to 3, The branching and merging portion is disposed on an outer periphery side of the plate-like member. holding device.

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