Holding device

Abstract

This invention provides a technology to improve the temperature distribution on the mounting surface of a plate-shaped member in a holding device. [Solution] The holding device is a plate-shaped member having a pair of main surfaces, and comprises a plate-shaped member having a flow path through which a refrigerant flows. The flow path has at least one branch-to-confluence section, which includes a branch section that branches the flow path into two branch flow paths, and a confluence section that merges the two branch flow paths branched by the branch section into one. The at least one branch-to-confluence section includes a main flow path formed along the flow path and a detour formed away from the main flow path in a cross section perpendicular to the central axis of the plate-shaped member, and includes a first branch-to-confluence section through which a virtual straight line connecting a first intersection and a second intersection, which are the intersection points of the outer lines constituting the detour and the main flow path, crosses an island-shaped section sandwiched between the main flow path and the detour.

Description

Technical Field

[0001] The present disclosure relates to a holding device.

Background Art

[0002] Conventionally, a holding device including a plate-like member having a placement surface on which an object is placed and a flow path through which a refrigerant flows is known (for example, Patent Document 1). In the technique described in Patent Document 1, a technique for reducing the variation in the temperature inside the wafer by improving heat conduction in the gap between the substrate and the support plate has been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, even with the technique described in Patent Document 1 above, there is still room for improvement in the technique for improving the temperature distribution on the placement surface of the plate-like member of the holding device.

[0005] An object of the present disclosure is to provide a technique for improving the temperature distribution on the placement surface of a plate-like member in a holding device.

Means for Solving the Problems

[0006] The present disclosure has been made to solve at least a part of the above-described problems and can be realized in the following forms.

[0007] (1) According to one embodiment of the present disclosure, a holding device is provided. The holding device comprises 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 on which an object is placed, and a flow path disposed inside the plate-shaped member through which a refrigerant flows, wherein the flow path has at least one branch-to-confluence section, which includes a branch section that branches the flow path into two branched flow paths, and a confluence section that brings together the two branched flow paths branched by the branch section into one, wherein the at least one branch-to-confluence section, in a cross section perpendicular to the central axis of the plate-shaped member including the flow path, has a main flow path formed along the flow path and a detour formed in a direction away from the main flow path, and includes a first branch-to-confluence section through which a virtual straight line connecting a first intersection and a second intersection, which are the intersections of the outer line constituting the detour and the main flow path, crosses an island-shaped section sandwiched between the main flow path and the detour.

[0008] According to this configuration, the refrigerant flow path of the plate-shaped member includes a branching section that divides the flow path into two branched flow paths, and a merging section that merges the two branched flow paths into one. As a result, the refrigerant flowing through one flow path branches into two branched flow paths, then merges back into a single flow path. This allows for a larger cooling area compared to, for example, the case where the refrigerant flows through only one flow path. Therefore, the degree of cooling in 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] Furthermore, in a cross-section perpendicular to the central axis of the plate-shaped member, the virtual straight line connecting the first and second intersections, which are the intersections of the outer lines constituting the detour and the main flow path, includes a first branching and merging section that crosses the island-shaped section sandwiched between the main flow path and the detour. Compared to the case where the virtual straight line does not cross the island-shaped section, the island-shaped section is located on the main flow path side, and the refrigerant collides with the island-shaped section at the branching section, making it easier for it to flow into the detour. As a result, the expected cooling effect can be obtained, and the temperature distribution on the mounting surface of the plate-shaped member can be improved.

[0010] (2) According to another embodiment of the present disclosure, a holding device is provided. The holding device comprises a plate-like member having a pair of main surfaces, the plate-like member having a mounting surface formed on one of the pair of main surfaces on which an object is placed, and a flow path disposed inside the plate-like member through which a refrigerant flows, wherein the flow path has at least one branch-to-confluence section, which includes a branch section that branches the flow path into two branched flow paths, and a confluence section that brings together the two branched flow paths branched by the branch section into one, wherein the at least one branch-to-confluence section includes a first branch-to-confluence section in a cross section perpendicular to the central axis of the plate-like member, which includes the flow path, and the two branched flow paths being formed along the flow path and a detour section formed away from the flow path, and a first branch-to-confluence section in which an imaginary line parallel to the outer line constituting the flow path crosses an island-like section sandwiched between the flow path and the detour section.

[0011] In this form of holding device, there is also a branching and merging section, and in a cross section perpendicular to the central axis of the plate-shaped member, a virtual line parallel to the outer line constituting the main flow path connects the first and second intersections, which are the intersection points of the outer line constituting the main flow path and the main flow path, and includes a first branching and merging section that crosses the island-shaped section sandwiched between the main flow path and the detour. Compared to the case where the virtual line does not cross the island-shaped section, the island-shaped section is located on the main flow path side, and similar to the above-described form of holding device, the refrigerant collides with the island-shaped section at the branching section, making it easier for it to flow into the detour. As a result, the expected cooling effect can be obtained, and the temperature distribution on the mounting surface of the plate-shaped member can be improved.

[0012] (3) In the holding device of the above form, the flow path has at least two adjacent branch-junctions, and in a cross section perpendicular to the central axis of the plate-shaped member including the flow path, at least one of the adjacent branch-junctions may be the first branch-junction. When there are two or more adjacent branch-junctions, there is a risk that the refrigerant will not flow into the bypass circuit as easily as when the branch-junctions are not adjacent. With this configuration, since at least one of the multiple adjacent branch-junctions is the first branch-junction, the refrigerant will flow more easily into the bypass circuit, and the temperature distribution on the mounting surface of the plate-shaped member can be improved.

[0013] (4) In the holding device of the above form, in a cross section perpendicular to the central axis of the plate-shaped member including the flow path, the flow path is spiral-shaped, and the bypass of the first branch junction may be located on the inner circumference side of the main flow path. When the bypass is located on the inner circumference side of the main flow path, refrigerant is less likely to flow into the bypass than when the bypass is located on the outer circumference side of the main flow path. In the case of the first branch junction, even if the bypass is located on the inner circumference side, the amount of refrigerant flowing into the bypass can be increased, and the expected cooling effect can be obtained.

[0014] (5) In the holding device of the above form, in a cross section perpendicular to the central axis of the plate-shaped member, including the flow path, the flow path has the main flow path and the bypass, and the bypass may have a branch merging section that faces the bypass of the first branch merging section. This configuration also has a first branch merging section, which improves the temperature distribution on the mounting surface of the plate-shaped member.

[0015] (6) In the holding device of the above form, in a cross section perpendicular to the central axis of the plate-shaped member, including the flow path, the width of the main flow path may be greater than the width of the bypass. Even in this case, the refrigerant flows more easily into the bypass at the first branching and merging section, so the expected cooling effect can be obtained.

[0016] Note that the present disclosure can be implemented in various forms. For example, it can be implemented in the form of a semiconductor manufacturing apparatus including a holding device, a manufacturing method of the holding device, a manufacturing method of a semiconductor, etc.

Brief Description of the Drawings

[0017] [Figure 1] It is a perspective view of the holding device. [Figure 2] It is a first cross-sectional view of the holding device. [Figure 3] It is a second cross-sectional view of the holding device. [Figure 4] It is an explanatory diagram of the first branch and confluence part. [Figure 5] It is an explanatory diagram of a method for determining the first intersection point and the second intersection point. [Figure 6] It is an explanatory diagram of the first branch and confluence part. [Figure 7] It is an explanatory diagram of the arrangement of the island-shaped part formed by the first branch and confluence part. [Figure 8] It is an explanatory diagram showing the flow of the refrigerant in the branch and confluence part. [Figure 9] It is an explanatory diagram showing an example in which a plurality of branch and confluence parts are gathered and provided. [Figure 10] It is an explanatory diagram of the definition of adjacent branch and confluence parts. [Figure 11] It shows the temperature distribution of the placement surface. [Figure 12] It is a diagram showing the cooling effect by the first branch and confluence part.

Embodiments for Carrying Out the Invention

[0018] <Embodiment> Figure 1 is a perspective view of a holding device 1 according to one embodiment of the present disclosure. Figure 2 is a first cross-sectional view of the holding device 1 of this embodiment. The holding device 1 is an electrostatic chuck that holds a substrate W by electrostatic attraction. The electrostatic chuck is used, for example, as a table on which to place the substrate W in an etching process using plasma in a chamber equipped with the electrostatic chuck. The holding device 1 comprises a base 10, a ceramic substrate 20, and a joint (not shown). In the holding device 1, as shown in Figure 1, the base 10 and the ceramic substrate 20 are stacked in that order. The holding device 1 positions the substrate W relative to the holding device 1 by using a focus ring FR installed on the outer circumference of the ceramic substrate 20. In Figures 1 and 2, for convenience, the stacking direction of the base 10 and the ceramic substrate 20 is shown as the z-axis direction, and the x-axis intersects perpendicular to the z-axis, and the y-axis intersects perpendicular to the z-axis and x-axis. For the sake of explanation, the size relationships of the base 10, ceramic substrate 20, and focus ring FR shown in Figures 1 and 2 do not reflect the actual relationships.

[0019] The base 10 is a sintered body mainly composed of silicon carbide (SiC), and is a roughly cylindrical member that forms the base of the holding device 1. Here, "main component" means the component with the highest proportion. The material forming the base 10 is not limited to a material mainly composed of silicon carbide. The base 10 may be formed from materials such as 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).

[0020] The base 10 comprises a first base 11 and a second base 12. The first base 11 and the second base 12 are joined together by an adhesive layer (not shown). The base 10 is not limited to a two-layer structure like the first base 11 and the second base 12; it may also be a single-layer structure or a structure consisting of three or more layers.

[0021] As shown in Figure 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 plate-like member with a substantially circular planar shape and has a pair of main surfaces 11a and 11b. On one of the pair of main surfaces 11a and 11b, the first base 11 has an inlet (not shown) for the refrigerant flowing through the flow path 30 (described later) to flow into the flow path 30, and an outlet (not shown) for the refrigerant to flow out of the flow path 30.

[0022] The second base 12 is stacked on the first base 11 on the positive side in the z-axis direction of the first base 11. The second base 12 is a plate-like member with a roughly circular planar shape and 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, a groove 13 is formed on the main surface 12b on the negative side in the z-axis direction, which serves as a flow path 30 through which the refrigerant flows. When the first base 11 and the second base 12 are joined together, the groove 13 formed in the second base 12 becomes a flow path 30 when the first base 11 acts as a cover for the groove 13. 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.

[0023] The ceramic substrate 20 is a plate-shaped member positioned on the positive side of the z-axis direction of the base 10. The ceramic substrate 20 is mainly composed of ceramics. In this embodiment, the ceramic substrate 20 is formed from a material mainly composed of aluminum oxide. However, 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.

[0024] The ceramic substrate 20 has a mounting surface 21 formed on one of its pair of main surfaces 20a, 20b, that is opposite to the base 10, on which the substrate W is placed. A mounting surface 22 for the focus ring FR is formed on the outer circumference of the other main surface 20a of the ceramic substrate 20. The other main surface 20b of the pair of main surfaces 20a, 20b of the ceramic substrate 20 is joined to the second base 12 by an adhesive layer (not shown). The ceramic substrate 20 has holes 23 that communicate with each of the multiple holes 14 formed in the base 10. The method of joining the base 10 and the ceramic substrate 20 is exemplified by, but is not limited to, metal joining, resin joining, or joining with inorganic materials.

[0025] The ceramic substrate 20 of this embodiment has electrodes 24. The electrodes 24 are located inside the ceramic substrate 20. The electrodes 24 are made of a conductive material such as tungsten or molybdenum. The electrodes 24 are connected to an external power source via electrode terminals (not shown) inserted through holes 14 and 23. Examples of electrodes 24 include high-frequency electrodes, chuck electrodes, and heater electrodes.

[0026] The holding device 1 of this embodiment has a hole 5a that penetrates the joint 5, which is made up of the base 10 and the ceramic substrate 20, in the z-axis direction through a hole 14 formed in the base 10 and a hole 23 formed in the ceramic substrate 20. The hole 5a in the joint 5 is used as a terminal hole for inserting a power supply terminal (not shown) for supplying power to an electrode 24 on the ceramic substrate 20, a gas hole for supplying helium gas to the back surface 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 so on. In this embodiment, the hole 5a in the joint 5 penetrates the joint 5 in the z-axis direction, but it does not have to penetrate the joint 5. Specifically, in the hole 5a, for example, the hole 14 that penetrates the base 10 may have a bottomed shape. If the hole 14 has a bottomed shape, the other main surface 20b of the ceramic substrate 20, or a counterbore hole formed in the other main surface 20b, becomes the bottom surface of the hole 5a. The joint 5 in this embodiment is also called a "plate-shaped member".

[0027] Next, the detailed shape of the flow path 30 of the holding device 1 will be described. Figure 3 is a second cross-sectional view of the holding device 1. Figure 3 is a cross-sectional view along line AA in Figure 2, and specifically, it is a cross-section perpendicular to the central axis C5 of the joint 5 including the flow path 30, and is a cross-section of the second base 12 in which the groove 13 is formed. Hereinafter, the cross-section shown in Figure 3 will also be referred to as the "cross-section including the flow path 30".

[0028] As shown in Figure 3, the flow path 30 in this embodiment is formed in a substantially spiral shape. The flow path 30 has a flow path inlet 30a for refrigerant from the outside to flow into the flow path 30, and a flow path outlet 30b for refrigerant that has flowed through the flow path 30 to flow 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 joint 5, flows counterclockwise toward the outer circumference of the base 10, and is discharged to the outside of the base 10 from the flow path outlet 30b. In Figure 3, the flow of refrigerant near the flow path inlet 30a and the flow path outlet 30b is indicated by arrows.

[0029] The flow path 30 of the holding device 1 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 into one. In the holding device 1 of this embodiment, for each of the plurality of branching and merging sections 31, 32, an island-like section without a hole 14 is formed between the two branching flow paths. In this embodiment, no hole 14 is formed in the island-like section, but in other embodiments, there may be a hole 14 in the island-like section.

[0030] As shown in the figure, in a cross-section including the channel 30, the branching and merging section 31 is formed such that each of the two branching channels curves away from each other. Also, in a cross-section including the channel 30, the branching and merging section 32 is a main channel in which one of the two branching channels is formed to run along the channel 30, and a detour in which the other is formed to curve away from the main channel. As will be described later, the multiple branching and merging sections 32 can be classified into a first branching and merging section 32A and a second branching and merging section 32B based on the arrangement of the island-like sections described above.

[0031] Figure 4 is an explanatory diagram of the first branching and merging section 32A. In Figure 4, section B, which includes one first branching and merging section 32A in Figure 3, is shown in an enlarged view. The first branching and merging section 32A has a branching section 323 that branches the flow path 30 into the main flow path 321 and the detour 322, and a merging section 324 that merges the main flow path 321 and the detour 322, which were branched by the branching section 323, into one. The second base 12 also has an island-shaped section 325A that is sandwiched between the main flow path 321 and the detour 322.

[0032] As shown in the figure, in a cross-section including the channel 30, a virtual straight line L2 connecting the first intersection point P1 and the second intersection point P2, which are the intersection points of the outer line L1 constituting the detour 322 and the main channel 321, crosses the island-shaped section 325A sandwiched between the main channel 321 and the detour 322. In the figure, the virtual straight line L2 is shown as a dashed line. The first intersection point P1 is the intersection point on the side of the branch section 323, and can therefore be called a branching point. The second intersection point P2 is the intersection point on the side of the confluence section 324, and can therefore be called a confluence point.

[0033] Figure 5 is an explanatory diagram of the method for determining the first intersection P1 and the second intersection P2. Similar to Figure 4, Figure 5 shows an enlarged view of section B, which includes the first branching and merging section 32A. In Figure 5, a dashed line L3 is shown to represent the channel 30 assuming that the width W1 of the main channel 321 is equal to the width W0 of the channel 30 before branching and after merging, that is, assuming that the section does not branch. In this embodiment, in the cross-section shown in Figure 5, the intersections of the outer line L1 constituting the detour 322 and the aforementioned dashed line L3 are defined as the first intersection P1 and the second intersection P2.

[0034] Figure 6 is an explanatory diagram of the first branching and merging section 32A. Like Figure 4, Figure 6 also shows an enlarged view of section B, which includes the first branching and merging section 32A. In Figure 6, the first intersection point P1 and the second intersection point P2, which are the intersection points of the outer line L1 constituting the detour 322 and the main channel 321, are connected, and a dashed-dotted line L5 parallel to the outer line L4 constituting the main channel 321 is shown. Since the dashed-dotted line L5 is parallel to the outer line L4 constituting the main channel 321, the distance between the dashed-dotted line L5 and line L4 is W1, which is constant.

[0035] As shown in the figure, in a cross-section including the channel 30, a virtual line L5, which connects the first intersection P1 and the second intersection P2, which are the intersections of the outer line L1 constituting the detour 322 and the main channel 321, and is parallel to the outer line L4 constituting the main channel 321, can also be said to cross the island-shaped portion 325A sandwiched between the main channel 321 and the detour 322.

[0036] Figure 7 is an explanatory diagram of the arrangement of the island-shaped section 325A formed by the first branching and merging section 32A. In Figure 7, the island-shaped section 325B formed by the second branching and merging section 32B is shown with diagonal hatching. At the second branching and merging section 32B, the width of the main channel 321 is approximately equal to the width of the channel 30 before branching and after merging, so the outline of the main channel side of the island-shaped section 325B approximately coincides with the virtual line L5. As shown in the figure, the virtual straight line L2 and virtual line L5 described above cross the island-shaped section 325A formed by the first branching and merging section 32A, but do not cross the island-shaped section 325B formed by the second branching and merging section 32B. Thus, among the branching and merging sections 32, those in which at least one of the virtual straight line L2 and virtual line L5 crosses the island-shaped section are called the "first branching and merging section 32A," and those in which neither the virtual straight line L2 nor the virtual line L5 crosses the island-shaped section are called the "second branching and merging section 32B."

[0037] Figure 8 is an explanatory diagram showing the flow of refrigerant in the branching / confluence section 32. Figure 8(A) shows the first branching / confluence section 32A, and Figure 8(B) shows the second branching / confluence section 32B. As shown in Figure 8(A), virtual lines L2 and L5 cross the island-shaped section 325A, which is sandwiched between the main flow path 321 and the bypass 322 of the first branching / confluence section 32A. In other words, the island-shaped section 325A is on the side of the main flow path 321. Therefore, the refrigerant is more likely to flow into the bypass 322 after hitting the island-shaped section 325A. In Figure 8, the flow of refrigerant is indicated by arrows.

[0038] On the other hand, as shown in Figure 8(B), the virtual straight line L2 and virtual line L5 do not cross the island-shaped section 325B sandwiched between the main channel 321 and the detour 322 of the second branching / merging section 32B. That is, in the second branching / merging section 32B, the width of the main channel 321 is approximately equal to the width of the channel 30 before branching and after merging. Therefore, after branching of the channel 30, the refrigerant tends to flow directly into the main channel 321 and does not tend to flow into the detour 322. In this way, in the first branching / merging section 32A, the refrigerant tends to flow into the detour 322 as well, which improves the uniformity of the temperature in the area where the first branching / merging section 32A is located.

[0039] FIG. 9 is an explanatory diagram showing an example in which a plurality of branch junctions 32 are provided together. In FIG. 9, a C portion including one first branch junction 32A and two second branch junctions 32B in FIG. 3 is shown enlarged. In FIG. 9, two adjacent branch junctions 32 and opposing branch junctions 32 are illustrated. In the example shown in FIG. 9, in one first branch junction 32A, the bypass 322 is arranged on the inner peripheral side of the flow path 30, and adjacent to the first branch junction 32A, a second branch junction 32B in which the bypass 322 is arranged on the inner periphery of the flow path 30 is arranged. Also, at a position opposing the first branch junction 32A, a second branch junction 32B in which the bypass 322 is arranged on the outer periphery of the flow path 30 is arranged.

[0040] FIG. 10 is an explanatory diagram of the definition of adjacent branch junctions 32. In the present embodiment, "adjacent" is defined as follows. For two branch junctions 32 provided with bypasses 322 on the same side with respect to the flow path 30, when the distance between the two branch junctions 32 is smaller than the distance between the first intersection point P1 and the second intersection point P2 of the branch junction 32, the two branch junctions 32 are said to be adjacent. As shown in FIG. 10, let the distance between the first intersection point P1 and the second intersection point P2 of the branch junction 32 on the left side of the paper surface be a, the distance between the first intersection point P1 and the second intersection point P2 of the branch junction 32 on the right side of the paper surface be b, and the distance between the second intersection point P2 of the branch junction 32 on the left side of the paper surface and the first intersection point P1 of the branch junction 32 on the right side of the paper surface be c. When c < a and c < b, it can be said that the two branch junctions 32 are adjacent. In the example of FIG. 10, the distance c is the distance between the two branch junctions 32.

[0041] In the example shown in FIG. 9, of the two adjacent branch junctions 32, one is the first branch junction 32A. By doing so, at least in the first branch junction 32A, since the refrigerant easily flows through the bypass 322, the uniformity of the in-plane temperature distribution of the mounting surface 21 can be improved as compared with the case where both of the two adjacent branch junctions 32 are the second branch junctions 32B.

[0042] Furthermore, of the two adjacent branch junctions 32, the refrigerant is less likely to flow into the detour 322 at the downstream branch junction 32 than at the upstream branch junction 32. In the example shown in Figure 9, since the downstream branch junction 32 is the first branch junction 32A, the uniformity of the in-plane temperature distribution on the mounting surface 21 can be improved compared to the case where only the upstream branch junction 32 is the first branch junction 32A. Note that in the example shown in Figure 9, only the downstream branch junction 32 is the first branch junction 32A, but it is preferable if both of the two adjacent branch junctions 32 are first branch junctions 32A, as this can further improve the uniformity of the in-plane temperature distribution on the mounting surface 21.

[0043] In the flow path 30, where branching and merging sections 32 are provided opposite each other, refrigerant is less likely to flow into the bypass section 322. In the example shown in Figure 9, one of the two opposing branching and merging sections 32 is the first branching and merging section 32A. In this case, at least at the first branching and merging section 32A, refrigerant is more likely to flow into the bypass section 322, thus improving the uniformity of the in-plane temperature distribution on the mounting surface 21 compared to the case where both opposing branching and merging sections 32 are second branching and merging sections 32B.

[0044] Furthermore, in the case of the branch junction 32 where the detour 322 is located inside the main flow path 321, the refrigerant is less likely to flow into the detour 322 than in the branch junction 32 where the detour 322 is located outside the main flow path 321. In the example shown in Figure 9, since the inner branch junction 32 is the first branch junction 32A, the uniformity of the in-plane temperature distribution on the mounting surface 21 can be improved compared to the case where only the outer branch junction 32 is the first branch junction 32A. Note that in the example shown in Figure 9, only the inner branch junction 32 is the first branch junction 32A, but it is preferable that both of the two opposing branch junction 32 are first branch junction 32A, as this can further improve the uniformity of the in-plane temperature distribution on the mounting surface 21.

[0045] Figure 11 shows the temperature distribution of the mounting surface 21. Figure 11 illustrates the results of a simulation of the temperature distribution of the mounting surface 21 under the simulation conditions shown below. The components of the holding device 1 are as follows: • Base 10: Ceramics mainly composed of silicon carbide (SiC) • Ceramic base material 20: Ceramics mainly composed of aluminum oxide • Joining of each component: Aluminum (Al) bond (metal bonding) The refrigerant was a fluorine-based inert liquid, and the substrate W was a Si wafer. <Heat input conditions> A total of 4kW of heat is applied to the surface of the substrate W and the focus ring FR. <Refrigerant conditions> A refrigerant at -20°C is circulated at a rate of 10 L / min.

[0046] The flow path 30 shown in Figure 11 has a slightly different shape from the flow path 30 shown in Figure 3, but it has a branching and merging section that corresponds to section C in Figure 3. In Figure 11, the section corresponding to section C in Figure 3 is enclosed in a square with a dashed line. In Figures 11(A) and (B), the branching and merging section 32 enclosed in a circle is the second branching and merging section 32B. In Figures 11(C) and (D), the branching and merging section 32 enclosed in a circle is the first branching and merging section 32A, which has the same configuration as section C in Figure 3. In Figures 11(A) and (C), the cross-sectional shape of the flow path 30 is superimposed on the temperature distribution of the mounting surface 21, while in Figures 11(B) and (D), only the temperature distribution of the mounting surface 21 is shown. As shown by the color bar in Figure 11, the darker the color, the lower the temperature, and the whiter the color, the higher the temperature.

[0047] Figure 12 shows the cooling effect of the first branch / junction 32A. Figure 12 shows the temperature difference between Figure 11(D) and Figure 11(B). This shows the cooling effect when the second branch / junction 32B is changed to the first branch / junction 32A.

[0048] Comparing Figure 11(B) and Figure 11(D), the temperature is lower in Figure 11(D) in the circled area. In particular, the temperature is significantly lower in the area corresponding to the bypass 322 of the first branch junction 32A (indicated by the arrow). As shown in Figure 12, the area where the first branch junction 32A is formed (indicated by the circle) is significantly cooled compared to the case where the second branch junction 32B is formed. In other words, it was confirmed that cooling performance can be improved by changing the second branch junction 32B to the first branch junction 32A.

[0049] As described above, according to the holding device 1 of this embodiment, the flow path 30 through which the refrigerant flows in the base 10 includes a branching and merging section 32 which has a branching section 323 that branches the flow path 30 into two branched flow paths, and a merging section 324 that merges the two branched flow paths into one. As a result, the refrigerant flowing through one flow path 30 branches into two branched flow paths, then merges and flows through one flow path 30 again. Therefore, compared to, for example, the case where the refrigerant flows through only one flow path, the area that is cooled can be increased. Consequently, the degree of cooling in each part of the base 10 can be adjusted, and the temperature distribution on the mounting surface 21 of the holding device 1 can be improved.

[0050] Furthermore, in a cross-section perpendicular to the central axis C5 of the holding device 1, the virtual straight line L2 and virtual line L5 connecting the first intersection P1 and the second intersection P2, which are the intersection points of the outer line L1 constituting the detour 322 and the main flow path 321, include the first branching and merging section 32A that crosses the island-shaped section 325A sandwiched between the main flow path 321 and the detour 322. Therefore, compared to the case where the virtual straight line L2 and virtual line L5 do not cross the island-shaped section, the island-shaped section 325A is located on the main flow path 321 side, making it easier for the refrigerant to flow into the detour 322 when it hits the island-shaped section 325A at the branching section 323. As a result, the expected cooling effect can be obtained, and the temperature distribution on the mounting surface 21 of the holding device 1 can be improved.

[0051] Therefore, for example, in an etching process using plasma in a chamber equipped with a holding device 1, the uniformity of heat dissipation of the substrate W placed on the mounting surface 21 of the holding device 1 can be improved.

[0052] Furthermore, in the holding device 1 of this embodiment, since the branch and confluence section 32 on the downstream side of the refrigerant flow is the first branch and confluence section 32A among the two adjacent branch and confluence sections 32, it is possible to make it easier for refrigerant to flow into the detour 322 in locations where it is more difficult for refrigerant to flow into the detour 322. As a result, the expected cooling effect can be obtained.

[0053] Furthermore, in the holding device 1 of this embodiment, the flow path 30 is spiral-shaped, and the bypass 322 of the first branch junction 32A is located on the inner circumference side of the main flow path 321. When the bypass 322 is located on the inner circumference side of the main flow path 321, refrigerant is less likely to flow into the bypass 322 than when the bypass 322 is located on the outer circumference side of the main flow path 321. In the case of the first branch junction 32A, even if the bypass 322 is located on the inner circumference side, the amount of refrigerant flowing into the bypass 322 can be increased, so the expected cooling effect can be obtained.

[0054] Furthermore, in the holding device 1 of this embodiment, a second branch-junction section 32B is positioned opposite the branch-junction section 32A, where the bypass 322 is located on the inner circumference side of the flow path 30, and the bypass 322 is located on the outer circumference side of the flow path 30. When two branch-junction sections 32 are provided facing each other, refrigerant does not easily flow through the bypass 322 located on the inner circumference side of the spiral flow path 30. Therefore, by making the branch-junction section 32 with the bypass 322 located on the inner circumference side the first branch-junction section 32A, the amount of refrigerant flowing through the bypass 322 can be increased, and the expected cooling effect can be obtained.

[0055] Furthermore, according to the holding device 1 of this embodiment, of the two branched flow paths included in the branching and merging section 32, the main flow path 321 is formed to conform to the shape of the flow path 30, while the bypass path 322 is formed to curve away from the main flow path 321. This makes it possible to add a range cooled by a relatively small amount of refrigerant flowing through the bypass path 322 to the range cooled by the refrigerant flowing through the main flow path 321, which allows a relatively large amount of refrigerant to flow easily. Therefore, the degree of freedom in adjusting the degree of cooling at each part of the joint 5 is improved, and the temperature distribution on the surface of the joint 5 can be further improved.

[0056] Furthermore, according to the holding device 1 of this embodiment, in the branching and merging section 32, the width of the main flow path 321 is greater than the width of the bypass 322, so less refrigerant flows through the bypass 322 than through the main flow path 321. As a result, by making the bypass 322 a shape with a relatively large curvature, that is, a shape with a sharp curvature and small curvature, refrigerant can flow even in places where it is difficult to form a branching flow path. Therefore, the area that is cooled to a relatively large degree by the refrigerant can be further enlarged, and the temperature distribution on the surface of the jointed body 5 can be further improved.

[0057] Furthermore, according to the holding device 1 of this embodiment, the detour 322 included in the branching / converging section 32 can be formed even in locations where it is difficult to form the two branching / converging channels 311 and 312 included in the branching / converging section 31. As a result, the branching / converging section 32 can be positioned on the outer circumference of the joint 5, where there are often constraints on the formation of the channel 30, such as the shape of the joint 5 or the position of the hole 14 formed in the base 10. Therefore, even locations where it is relatively difficult to form the channel 30 can be included in the range where the degree of cooling by the refrigerant is relatively large, thereby further improving the temperature distribution on the surface of the joint 5.

[0058] Furthermore, according to the holding device 1 of this embodiment, the branching and merging section 32 is positioned on the outer periphery of the joint 5, where there are often constraints on the formation of the flow path 30. As a result, when the substrate W is placed on the mounting surface 21, the outer periphery of the joint 5, which corresponds to the outer periphery of the substrate W and tends to become relatively hot, can be cooled by the coolant flowing through the branching and merging section 32. Therefore, the temperature distribution on the surface of the joint 5 can be further improved.

[0059] <Modified form of this embodiment> This disclosure is not limited to the embodiments described above, and can be implemented in various forms without departing from its essence, including, for example, the following modifications.

[0060] In the above-described embodiment, the flow path 30 is assumed to have multiple branching and merging sections 31 and 32, but the number of branching and merging sections in the flow path of the holding device is not limited to this. There may be only one. Also, although the flow path 30 is assumed to have branching and merging sections 31 and 32 with different configurations, the branching and merging sections in the flow path 30 do not necessarily have to include branching and merging sections 31.

[0061] In the above-described embodiment, the detour 322 was assumed to be formed to curve away from the main flow path 321, but the detour only needs to be formed in a direction away from the main flow path 321, and may be formed to bend (fold) in a direction away from the main flow path 321.

[0062] In the above embodiment, an example was shown in which the island-shaped section 325A is crossed by a virtual straight line L2 and a virtual line L5 in the first branching / merging section 32A. However, it is sufficient if either the virtual straight line L2 or the virtual line L5 crosses the island-shaped section 325A.

[0063] In the above embodiment, an example was shown where the branch junction 32 downstream of the refrigerant flow is the first branch junction 32A among two adjacent branch junctions 32. However, the upstream branch junction 32 may be the first branch junction 32A, or both may be the first branch junction 32A.

[0064] The number of adjacent branching / merging sections 32 is not limited to the above embodiment and may be 3 or more. If 3 or more branching / merging sections 32 are provided adjacent to each other, at least one of the branching / merging sections 32 should be the first branching / merging section 32A.

[0065] In the above-described embodiment, an example was shown where the inner branch-to-junction section 32 of two opposing branch-to-junction sections 32 is the first branch-to-junction section 32A. However, the outer branch-to-junction section 32 may also be the first branch-to-junction section 32A. Furthermore, both of the two opposing branch-to-junction sections 32 may be the first branch-to-junction section 32A.

[0066] • In the above-described embodiment, an example was shown in which the width of the main channel 321 is greater than the width of the bypass 322, but the width of the main channel 321 may be less than or equal to the width of the bypass 322.

[0067] In the above embodiment, the holes 14 and 23 formed in the holding device were assumed to penetrate the holding device, as shown in Figure 2. However, the holes 14 and 23 do not necessarily have to penetrate the base 10.

[0068] In the above-described embodiment, the holding device comprises a base, a ceramic substrate, and a joint, but the configuration of the holding device is not limited to this. It may be a single plate-like member in which the portion corresponding to the base and the portion corresponding to the ceramic substrate are integrated. Furthermore, the portion corresponding to the joint may be omitted, and the member corresponding to the base and the member corresponding to the ceramic substrate may be joined by diffusion bonding.

[0069] In the above-described embodiment, in addition to the high-frequency electrode, the chuck electrode and heater electrode are arranged on the ceramic substrate. These electrodes may also be arranged on a base.

[0070] The embodiments of this specification have been described above based on the embodiments and modifications described above. The embodiments described above are for the purpose of facilitating understanding of this specification and do not limit it. This specification may be modified and improved without departing from its spirit and the scope of the claims, and equivalents thereof are included in this specification. Furthermore, any technical features that are not described as essential in this specification may be deleted as appropriate.

[0071] <Application Example 1> A holding device, A plate-like member having a pair of main surfaces, comprising a mounting surface formed on one of the pair of main surfaces on which an object is placed, and a flow path disposed inside the plate-like member through which a refrigerant flows, The flow path has at least one branching / merging section, which includes a branching section that branches the flow path into two branched flow paths, and a merging section that merges the two branched flow paths into one. The aforementioned at least one branching / merging section is, In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The two aforementioned branched channels, This channel is formed to follow the aforementioned channel, This is a detour formed in a direction away from the main flow path, The virtual straight line connecting the first and second intersections, which are the intersections of the outer line constituting the detour and the main channel, is characterized in that it includes a first branching and merging section that crosses the island-like section sandwiched between the main channel and the detour. holding device. <Application Example 2> A holding device, A plate-like member having a pair of main surfaces, comprising a mounting surface formed on one of the pair of main surfaces on which an object is placed, and a flow path disposed inside the plate-like member through which a refrigerant flows, The flow path has at least one branching / merging section, which includes a branching section that branches the flow path into two branched flow paths, and a merging section that merges the two branched flow paths into one. The aforementioned at least one branching / merging section is, In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The two aforementioned branched channels, This channel is formed to follow the aforementioned channel, This is a detour formed in a direction away from the main flow path, The invention is characterized in that a first intersection and a second intersection, which are the intersection points of the outer line constituting the bypass and the main channel, are connected, and a virtual line parallel to the outer line constituting the main channel includes a first branching and merging section that crosses an island-like section sandwiched between the main channel and the bypass. holding device. <Application Example 3> A holding device as described in Application Example 1 or Application Example 2, The flow path has at least two adjacent branching and merging sections, In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The present invention is characterized in that, of the adjacent branching and merging sections, at least one of the branching and merging sections is the first branching and merging section. holding device. <Application Example 4> A holding device described in any one of the examples from Application Example 1 to Application Example 3, In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The aforementioned channel is spiral-shaped, The detour of the first branching and merging section is characterized by being located on the inner circumference side of the main flow path. holding device. <Application Example 5> A holding device described in any one of Application Examples 1 to 4, In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The aforementioned flow path is The main channel and the bypass are provided, and the bypass has a branching section that faces the bypass of the first branching section. holding device. <Application Example 6> A holding device described in any one of Application Examples 1 to 5. In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The width of the main channel is characterized by being greater than the width of the bypass. holding device. [Explanation of symbols]

[0072] 1,2...holding device 5…Zygote 10…Base 11a, 11b, 12a, 12b,...base 14, 23… holes 20…Ceramic base material 21… Mounting surface 30…flow channel 31, 32... Junction / Confluence 32A...First branching and merging section 32B...Second branching and merging section 321...Main channel 322...Detour 323... Branching point 324... Junction 325B, 325A…Island part L2…Virtual line L5…Virtual line P1…1st intersection P2…Second intersection

Claims

1. A holding device, A plate-like member having a pair of main surfaces, comprising a mounting surface formed on one of the pair of main surfaces on which an object is placed, and a flow path disposed inside the plate-like member through which a refrigerant flows, The flow path has at least one branching / merging section, which includes a branching section that branches the flow path into two branched flow paths, and a merging section that merges the two branched flow paths into one. The aforementioned at least one branching / merging section is, In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The two aforementioned branched channels, This channel is formed to follow the aforementioned channel, This is a detour formed in a direction away from the main flow path, The virtual straight line connecting the first and second intersections, which are the intersections of the outer line constituting the detour and the main channel, is characterized in that it includes a first branching and merging section that crosses the island-like section sandwiched between the main channel and the detour. holding device.

2. A holding device, A plate-like member having a pair of main surfaces, comprising a mounting surface formed on one of the pair of main surfaces on which an object is placed, and a flow path disposed inside the plate-like member through which a refrigerant flows, The flow path has at least one branching / merging section, which includes a branching section that branches the flow path into two branched flow paths, and a merging section that merges the two branched flow paths into one. The aforementioned at least one branching / merging section is, In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The two aforementioned branched channels, This channel is formed to follow the aforementioned channel, This is a detour formed in a direction away from the main flow path, The invention is characterized in that a first intersection and a second intersection, which are the intersection points of the outer line constituting the bypass and the main channel, are connected, and a virtual line parallel to the outer line constituting the main channel includes a first branching and merging section that crosses an island-like section sandwiched between the main channel and the bypass. holding device.

3. A holding device according to claim 1 or claim 2, The flow path has at least two adjacent branching and merging sections, In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The present invention is characterized in that, of the adjacent branching and merging sections, at least one of the branching and merging sections is the first branching and merging section. holding device.

4. A holding device according to claim 1 or claim 2, In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The aforementioned channel is spiral-shaped, The detour of the first branching and merging section is characterized by being located on the inner circumference side of the main flow path. holding device.

5. A holding device according to claim 1 or claim 2, In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The aforementioned flow path is The main channel and the bypass are provided, and the bypass has a branching section that faces the bypass of the first branching section. holding device.

6. A holding device according to claim 1 or claim 2, In a cross-section perpendicular to the central axis of the plate-like member, including the aforementioned flow path, The width of the main channel is characterized by being greater than the width of the bypass. holding device.

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