Base and holding device

Abstract

In a holding device, another technique is provided for adjusting the in-plane temperature of the mounting surface of a plate-shaped member. [Solution] A plate-shaped base having a flow path through which a refrigerant flows and a pair of main surfaces, the flow path has at least one branching and merging section, which includes a branching section that divides the flow path into a first branched flow path and a second branched flow path, and a merging section that merges the first branched flow path and the second branched flow path into one, wherein the cross-sectional area of ​​the second branched flow path is smaller than the cross-sectional area of ​​the first branched flow path.

Description

Technical Field

[0001] The present disclosure relates to a base and 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. In such a holding device, a technique for making the temperature of a substrate as an object uniform has been proposed. For example, in Patent Document 1, a technique for correcting the temperature distribution of a substrate without changing the basic flow path shape by locally changing the flow velocity of a refrigerant by providing a protruding member on a base in which a flow path is formed in a holding device has been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Recently, the semiconductor manufacturing process has become highly heat-generating, and in order to maintain a substrate placed on the placement surface of a holding device at a predetermined process temperature, it is necessary to transfer a large amount of heat and exhaust the heat. In such a holding device, there may be provided a terminal hole through which a power supply terminal for supplying power to an electrode, a gas hole for supplying He gas to the back surface of a wafer as an object, and a lift pin hole for inserting a lift pin for lifting the wafer from the placement surface. Due to restrictions such as these various holes, if the refrigerant flow paths are arranged unevenly, a local temperature distribution may显著 occur on the placement surface. However, with the technique of Patent Document 1, due to restrictions such as the above various holes, the desired effect may not be obtained.

[0005] An object of the present disclosure is to provide another technique for adjusting the in-plane temperature of the placement surface of a plate-like member in a holding device. [Means for solving the problem]

[0006] This disclosure is made to solve at least some of the problems described above and can be implemented in the following forms.

[0007] (1) According to one embodiment of the present disclosure, a plate-shaped base is provided having a flow path through which a refrigerant flows and having a pair of main surfaces. In this base, the flow path has at least one branch-to-confluence section including a branch section that branches the flow path into a first branch flow path and a second branch flow path, and a confluence section that merges the first branch flow path and the second branch flow path into one, wherein the cross-sectional area of ​​the second branch flow path is smaller than the cross-sectional area of ​​the first branch flow path.

[0008] With this configuration, the refrigerant flowing through a single channel branches into a first branch channel and a second branch channel, then merges back into a single channel. This allows for a larger cooling area compared to, for example, a case where the refrigerant flows through only one channel.

[0009] Furthermore, the cross-sectional area of ​​the second branch channel is smaller than that of the first branch channel. Here, the cross-sectional area is the area of ​​the cross-section perpendicular to the flow direction centerline of each channel. By appropriately adjusting the cross-sectional area, the flow rate and velocity of the refrigerant can be changed. Therefore, by providing the second branch channel at a location where temperature fine-tuning is desired, the temperature of the main surface of the base can be partially fine-tuned. As a result, the uniformity of the in-plane temperature on the main surface of the base can be improved, or a desired temperature difference can be created within the plane.

[0010] (2) A base of the above form, wherein the flow path has a portion that is formed in a spiral shape or bent, the first branch flow path is formed to follow the flow path, and the second branch flow path is formed to connect adjacent first branch flow paths. When the second branch flow path is formed to follow the flow path and connects adjacent first branch flow paths, the amount of refrigerant flowing through the first flow path is reduced to the amount of refrigerant flowing through the flow path before branching, so the temperature of that portion can be slightly increased. In this way, the uniformity of the in-plane temperature on the main surface of the base can be improved, or a desired temperature difference can be provided within the plane.

[0011] (3) The base in the above configuration, wherein the first branch channel and the second branch channel face each other. In this configuration, since the cross-sectional area of ​​the second branch channel is smaller than the cross-sectional area of ​​the first branch channel, the temperature at a desired location can be adjusted by adjusting the difference in cross-sectional area, thereby improving the uniformity of the in-plane temperature on the main surface of the base or creating a desired temperature difference within the plane.

[0012] (4) The base according to the above configuration, wherein the flow path may have a plurality of branching and merging sections. By providing each of the plurality of branching and merging sections at locations where temperature adjustment is desired, the uniformity of the in-plane temperature of the main surface of the base can be further improved, or a desired temperature difference can be provided at desired locations within the plane.

[0013] (5) In the base of the above form, the second branch channel may have a first portion having a predetermined depth and a second portion having a depth different from the depth of the aforementioned portion. In this way, the cooling of the base by the refrigerant flowing through the second branch channel can be adjusted more precisely.

[0014] (6) According to another embodiment of the present disclosure, a holding device is provided. This holding device has a plate-like portion having a mounting surface on which an object is placed, and a base supporting the plate-like portion, wherein the base is the base of the above embodiment. According to this embodiment of the holding device, because it has the base of the above embodiment, it is possible to improve the uniformity of the in-plane temperature of the mounting surface of the holding device or to create a desired temperature difference within the surface.

[0015] Note that the present disclosure can be implemented in various forms, for example, 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, and the like.

Brief Description of the Drawings

[0016] [Figure 1] It is a perspective view of the holding device of the first embodiment. [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 view of the branch and confluence part of the first embodiment. [Figure 5] It is an explanatory view showing the depths of the first branch flow path and the second branch flow path. [Figure 6] It is an explanatory view showing the first branch flow path and the second branch flow path. [Figure 7] It is an explanatory view showing the flow path of the holding device of the second embodiment. [Figure 8] It is an explanatory view of the flow path. [Figure 9] It is an explanatory view showing an enlarged view of the vicinity of the branch part and the confluence part of the branch and confluence part. [Figure 10] It is an explanatory view showing the depths of the first branch flow path and the second branch flow path. [Figure 11] It is a diagram showing the temperature adjustment effect by the branch and confluence part. [Figure 12] It is an explanatory view showing the depth of the branch flow path in the holding device of the third embodiment. [Figure 13] It is an explanatory view showing the flow path of the holding device of the fourth embodiment.

Modes for Carrying Out the Invention

[0017] <First Embodiment> Figure 1 is a perspective view of a holding device 1 according to a first 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 FS 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.

[0018] The base 10 is a sintered body mainly composed of silicon carbide (SiC), and is a substantially cylindrical member that forms the base of the holding device 1. Here, "main component" refers to the component with the highest proportion. By making silicon carbide, which has high corrosion resistance, the main component of the base 10, a water-based refrigerant can be used. Furthermore, silicon carbide has high thermal conductivity and can be suitably used as a ceramic substrate for cooling. The thermal conductivity of the base 10 is not particularly limited, but it is preferable to form it with ceramics that have a thermal conductivity of 70 W / mK or higher. In addition, since silicon carbide is conductive, it can also be used as an electrode for high-frequency current.

[0019] Furthermore, 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, metal-ceramic composites (MMCs) such as Al-SiC, or ceramic materials mainly composed of aluminum nitride (AlN) or alumina (Al2O3). By making the base 10 a composite of ceramics and metal, the coefficient of thermal expansion (CTE) becomes easier to adjust and the toughness is improved, making it easier to use as a base.

[0020] The thickness of the base 10 is not particularly limited, but is preferably 10 mm to 50 mm, and more preferably 15 mm to 30 mm. In this specification, when numerical ranges are described using "~", unless otherwise specified, the lower limit and upper limit are included. For example, the description "10~20" includes both the lower limit "10" and the upper limit "20". In other words, "10~20" has the same meaning as "10 or more and 20 or less".

[0021] The diameter of the base 10 is not particularly limited, but it should be greater than or equal to the outer diameter of the substrate W that will be held. For example, if the diameter of the substrate W is 300 mm, the diameter of the base 10 will be 300 mm or more.

[0022] The base 10 comprises a first base 11 and a second base 12. The first base 11 and the second base 12 are joined by an adhesive layer (not shown). The first base 11 and the second base 12 may also be joined by diffusion bonding under high pressure and high temperature. Furthermore, the base 10 is not limited to a two-layer structure like the first base 11 and the second base 12, but may also be a single-layer structure or a structure consisting of three or more layers.

[0023] 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.

[0024] 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.

[0025] The base 10 can be manufactured by various known manufacturing methods. For example, the raw material powder can be CIP molded (cold isostatic pressing), the molded body can be processed, the molded body can be degreased and then fired, and the base 10 can be completed by further processing after firing.

[0026] The grooves 13 in the second base 12 may be formed by machining on the molded body before firing, or by machining after firing. Furthermore, if the second base 12 is formed from a conductive material such as silicon carbide, the grooves 13 may be formed by electrical discharge machining.

[0027] Furthermore, a conductive film may be formed on the surface of the base 10. If the conductivity of the base 10 is insufficient, it can be used as a high-frequency electrode by forming a conductive film on the surface of the base 10 (main surface 12a and side surface).

[0028] The ceramic substrate 20 is a plate-shaped member positioned on the positive side in 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, silicon carbide, or yttria (Y2O3). The ceramic substrate 20 has a pair of main surfaces 20a and 20b.

[0029] The ceramic substrate 20 has a mounting surface 21 formed on one of its pair of main surfaces 20a, 20b, opposite to the base 10, on which the substrate W is placed. A mounting surface 22 for the focus ring FS is formed on the outer circumference of the one 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. Furthermore, the base 10 and the ceramic substrate 20 may be integrally formed from a single material without a joining layer.

[0030] The ceramic substrate 20 of this embodiment has electrodes 24. The electrodes 24 are located inside the ceramic substrate 20. The electrodes 24 are formed from 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. The ceramic substrate 20 in this embodiment is also referred to as the "plate-like portion".

[0031] 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.

[0032] Next, we will describe the detailed shape of the flow path 30 of the holding device 1. 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".

[0033] 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.

[0034] The flow path 30 of the holding device 1 has a plurality of branching and merging sections 31. Each of the plurality of branching and merging sections 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 into one. In the holding device 1 of this embodiment, for each of the plurality of branching and merging sections 31, 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.

[0035] As shown in the figure, in a cross-section including the flow path 30, the branching and merging section 31 is formed such that each of the two branching flow paths curves away from each other and faces the other.

[0036] Figure 4 is an explanatory diagram of the branching and merging section 31 of the first embodiment. Figure 4 is an enlarged view of section B in Figure 3, and is an enlarged cross-sectional view including one of the branching and merging sections 31 among the plurality of branching and merging sections 31. The branching and merging section 31 shown in Figure 4 has a branching section 313 that branches the flow path 30 into a first branching flow path 311 and a second branching flow path 312, and a merging section 314 that merges the first branching flow path 311 and the second branching flow path 312, which were branched by the branching section 313, into one.

[0037] In the holding device 1, the branching and merging section 31 is formed such that, in a cross-section including the flow path 30 as shown in Figure 4, the first branching flow path 311 and the second branching flow path 312 are curved in directions away from each other and face each other. Specifically, using the center line C30 of the flow path 30 shown in Figure 4, the first branching flow path 311 and the second branching flow path 312 are formed so as not to include the center line C30 of the flow path 30. The first branching flow path 311 is formed to bulge inward from the joint 5 in the direction of the central axis C5 of the joint 5 when viewed from the center line C30 of the flow path 30. The second branching flow path 312 is formed to bulge outward from the joint 5 in the direction away from the central axis C5 of the joint 5 when viewed from the center line C30 of the flow path 30. As a result, the island-shaped portion 315 sandwiched between the first branch channel 311 and the second branch channel 312 is a part that is cooled to a relatively large extent by the refrigerant flowing through the first branch channel 311 and the second branch channel 312, thereby increasing the area that is cooled to a relatively large extent by the refrigerant.

[0038] Figure 5 is an explanatory diagram showing the depths of the first branch channel 311 and the second branch channel 312. Figure 5(A) shows the cross-section along line CC shown in Figure 4, and shows the cross-section of the channel 30. Figure 5(B) shows the cross-section along line DD shown in Figure 4, and shows the cross-sections of the first branch channel 311 and the second branch channel 312. Here, the cross-section is a cross-section perpendicular to the flow direction centerline of the channel, and in this example, it is a cross-section parallel to the central axis C5 of the joint 5.

[0039] As shown in Figure 5(B), the depth D2 of the second branch channel 312 is smaller than the depth D1 of the first branch channel 311, and the width W2 of the second branch channel 312 is the same as the width W1 of the first branch channel 311. Therefore, the cross-sectional area of ​​the second branch channel 312 is smaller than the cross-sectional area of ​​the first branch channel 311. In this embodiment, the depth D1 of the first branch channel 311 is the same as the depth D0 of the channel 30, but the depth D1 of the first branch channel 311 may be different from the depth D0 of the channel 30. As shown in the figure, the depth of each channel is the distance from the top to the bottom of the channel. The cross-sectional area of ​​each branch channel is measured at multiple locations (for example, five equally spaced locations), and the average value is used.

[0040] Figure 6 is an explanatory diagram showing the first branch channel 311 and the second branch channel 312. In Figure 6, the second branch channel 312 is shown with diagonal hatching. In this embodiment, the depth is constant (depth D1) throughout the entire first branch channel 311, and the depth is constant (depth D2) throughout the entire second branch channel 312 (the part with diagonal hatching in the figure). In Figure 6, as an example of the ends of the first branch channel 311 and the second branch channel 312, perpendicular lines are drawn from the inner lines L1 and L2 of each branch channel to define them. The method for determining the ends of the first branch channel 311 and the second branch channel 312 is not limited to the example shown in Figure 6, and can be determined by various methods. For example, the ends of the first branch channel 311 and the second branch channel 312 may be determined by lines perpendicular to the center line C30 of the channel 30.

[0041] In the holding device 1 of this embodiment, the flow path 30 of the base 10 has a branching and merging section 31, and the refrigerant flowing through one flow path 30 branches into a first branching flow path 311 and a second branching flow path 312, then merges and flows again through one flow path 30. Therefore, compared to, for example, the case where the refrigerant flows through only one flow path, the area that is cooled can be increased.

[0042] Furthermore, the cross-sectional area of ​​the second branch channel 312 is smaller than the cross-sectional area of ​​the first branch channel 311. Since the amount of refrigerant flowing through the second branch channel 312 is less than the amount of refrigerant flowing through the first branch channel 311, the degree of cooling can be finely adjusted. As a result, the uniformity of the in-plane temperature of the main surface 12a of the base 10 can be improved, or a desired temperature difference can be created within the surface. As a result, the uniformity of the in-plane temperature of the mounting surface 21 of the holding device 1 can be improved, or a desired temperature difference can be created within the surface.

[0043] <Second Embodiment> Figure 7 is an explanatory diagram showing the flow path 30A of the holding device 1A of the second embodiment. Figure 7 is a diagram showing a cross-section corresponding to Figure 3 of the first embodiment. In the holding device 1A of the second embodiment, the shape of the flow path 30A is different from the flow path 30 of the first embodiment. In the holding device 1A, the flow path 30A is formed in a substantially spiral shape, similar to the first embodiment, but the arrangement of the flow path inlet 30a for the refrigerant from the outside to flow into the flow path 30 and the flow path outlet 30b for the refrigerant that has flowed through the flow path 30 to flow out of the flow path 30 is different from the flow path 30 of the first embodiment. That is, in the holding device 1A of this embodiment, the refrigerant flows into the flow path 30A from the flow path inlet 30a located on the outer circumference of the base 10A, flows counterclockwise toward the central axis C5 of the base 10, and is discharged to the outside of the base 10 from the flow path outlet 30b near the central axis C5 of the joint 5. In Figure 7, the flow of refrigerant near the flow path inlet 30a and the flow path outlet 30b is indicated by arrows. Furthermore, the shape of the branching and merging section 31A of the flow path 30A differs from that of the branching and merging section 31 in the first embodiment. In the embodiments described below, the same reference numerals are used for components identical to those in the holding device 1 of the first embodiment, and refer to the preceding descriptions.

[0044] Figure 8 is an explanatory diagram of the flow path 30A. Figure 8 shows a cross-sectional view corresponding to Figure 7. In Figure 8, the first branch flow path 311A ​​is shown with hatching. The end of the first branch flow path 311A ​​is defined in the same way as in the first embodiment. As shown in the figure, in the cross-section including the flow path 30A, the first branch flow path is formed to follow the flow path 30, and the second branch flow path is formed to connect adjacent first branch flow paths. In the example shown in Figure 8, the branch merging section 31A has the first branch flow path 311A, shown with hatching, and the second branch flow path 312A.

[0045] In Figure 8, the flow of refrigerant near the branching section 313A and the confluence section 314A is also indicated by arrows. As shown in the figure, the refrigerant flowing in from the flow path inlet 30a and flowing through the flow path 30A branches into the first branch flow path 311A ​​and the second branch flow path 312A at the branching section 313A, and then merges at the confluence section 314A to flow through the flow path 30A. That is, the amount of refrigerant flowing through the first branch flow path 311A ​​is less than the amount of refrigerant flowing through the flow path 30A upstream of the branching section 313A. The amount of refrigerant flowing through the flow path 30A downstream of the confluence section 314A is the same as the amount of refrigerant flowing through the flow path 30A upstream of the branching section 313A. Therefore, the area near where the first branch flow path 311A ​​is located can reduce the degree of cooling of the main surface of the base 10, that is, the temperature of the main surface can be made higher than when the flow path does not branch.

[0046] Figure 9 is an enlarged explanatory diagram showing the vicinity of branch section 313A and merging section 314A of branching / merging section 31A. The figure shows the widths of the first branching channel 311A ​​and the second branching channel 312A. As shown in the figure, the widths W3 and W4 of the first branching channel 311A ​​and the width W5 of the second branching channel 312A are approximately equal. As shown in Figure 8, the width of the first branching channel 311A ​​is approximately constant throughout (the part with hatched lines in the figure), and the width of the second branching channel 312A is also approximately constant throughout. In this example, the average value of the width of the first branching channel 311A ​​is approximately equal to the average value of the width of the second branching channel 312A.

[0047] Figure 10 is an explanatory diagram showing the depths of the first branch channel 311A ​​and the second branch channel 312A. Figure 10 is a cross-sectional view along the FF line in Figure 9. As shown, the depth D2 of the second branch channel 312A is smaller than the depth D1 of the first branch channel 311A. The depth of the first branch channel 311A ​​is approximately constant throughout (the part with hatched lines in the figure) (depth D1), and the depth of the second branch channel 312A is also approximately constant throughout (depth D2). Therefore, the cross-sectional area of ​​the second branch channel 312 is smaller than the cross-sectional area of ​​the first branch channel 311. In this case, the amount of refrigerant flowing through the second branch channel 312A is less than the amount of refrigerant flowing through the first branch channel 311A. In this embodiment as well, the depth D1 of the first branch channel 311A ​​is the same as the depth of channel 30A, but the depth D1 of the first branch channel 311A ​​may be different from the depth of channel 30.

[0048] Figure 11 shows the temperature control effect of the branching / merging section 31B in the embodiment. Figure 11 shows 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 1A are as follows: • Base 10A: Ceramics mainly composed of silicon carbide (SiC) • Ceramic base material 20: Ceramics mainly composed of aluminum oxide • Focus ring FR: Ceramics with silicon carbide (SiC) as the main component • 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.

[0049] Figures 11(A), (C), and (E) show cross-sections corresponding to Figure 7. Figure 11(A) shows the flow path 30P1 of the holding device 1P1 of the first comparative example, and Figure 11(B) shows the temperature distribution of the mounting surface of the holding device 1P1. Figure 11(C) shows the flow path 30P2 of the holding device 1P2 of the second comparative example, and Figure 11(D) shows the temperature distribution of the mounting surface of the holding device 1P2. Figure 11(E) shows the flow path 30B of the holding device 1B of the embodiment of the present disclosure, and Figure 11(F) shows the temperature distribution of the mounting surface of the holding device 1B. Figures 11(B), (D), and (F) show the areas corresponding to section E in Figures 11(A), (C), and (D), respectively. 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.

[0050] In the first comparative example, 30P1 does not have a branched channel (Figure 11(A)). In the second comparative example, 30P2 has a branched channel 30P2 and a branched junction 31P2 having a second branched channel 312P2 connecting the adjacent first branched channel 311P2. In this example, the first branched channel 311P2 and the second branched channel 312P2 have equal width and depth, and equal cross-sectional area. In the holding device 1B shown in Figure 11(E), the channel 30B has the same shape as the channel 30P2 of the second comparative example, but the width of the second branched channel 312B is narrower than that of the second branched channel 312P2 of the second comparative example. The depths of the channels 30P1, 30P2, and 30B are equal. That is, the depths of the first branched channel 311P2, the second branched channel 312P2, the branched channel 311B, and the second branched channel 312B are equal.

[0051] The temperature of portion E of the mounting surface of the second comparative example's holding device 1P2 is lower than that of the first comparative example's holding device 1P1. In particular, the temperature is lower in the area where the second branched channel 312P2 is formed compared to the first comparative example's holding device 1P1, and the temperature of portion E as a whole is lower. In the second comparative example's holding device 1P2, the channel 30P2 is branched, and by having a branched junction section 31P2 with a second branched channel 312P2 connecting the adjacent first branched channels 311P2, it can be said that the temperature of portion E of the mounting surface was lower than that of the first comparative example's holding device 1P1.

[0052] The temperature of portion E of the mounting surface of the holding device 1B of the embodiment is even lower compared to the holding device 1P2 of the second comparative example. In particular, the temperature of the area where the second branch channel 312B is formed is lower than that of the holding device 1P2 of the second comparative example, and the temperature of portion E as a whole is lower. In the holding device 1B of the embodiment, although the width of the second branch channel 312B is different from that of the second branch channel 312P2 of the second comparative example, the other configurations are the same, so it can be said that the cooling performance of that portion was improved by narrowing the width of the second branch channel 312B. In other words, by making the cross-sectional area of ​​the second branch channel 312B smaller than the cross-sectional area of ​​the first branch channel 311B, it can be said that the cooling performance by the second channel 30P2 was improved compared to when the cross-sectional areas of the second branch channel and the first branch channel are equal. The cross-sectional area of ​​the second branch channel only needs to be smaller than the cross-sectional area of ​​the first branch channel, and it is sufficient to make either the width or depth, or both, different from that of the first branch channel.

[0053] As described above, the holding devices 1A and 1B of this embodiment can also be used to obtain the desired cooling performance by arranging the second branched flow path at the desired location.

[0054] <Third Embodiment> Figure 12 is an explanatory diagram showing the depths of the first branch channel 311C and the second branch channel 312C in the holding device 1C of the third embodiment. In the holding device 1C of the third embodiment, the depth of the second branch channel 312C of channel 30C differs from that of the second embodiment. Figure 12 illustrates the location corresponding to Figure 10.

[0055] As shown in the figure, the second branch channel 312C of this embodiment has a first portion 318 having a depth D2 and a second portion 319 having a depth D3 different from that of the first portion 318. This allows for more precise control of the cooling by the refrigerant flowing through the second branch channel 312C. In the example shown in Figure 12, the depth of the second portion 319 is shallower than that of the first portion 318, but the depth of the second portion 319 may be deeper than that of the first portion 318. Both depth D2 and depth D3 are smaller than depth D1.

[0056] <Fourth Embodiment> Figure 13 is an explanatory diagram showing the flow path 30D of the holding device 1D of the fourth embodiment. Figure 13 is a diagram showing a cross-section corresponding to Figure 3 of the first embodiment. The flow path 30D of this embodiment includes a portion that is formed by bending. The portion that is formed by bending is generally also called a "serpentine shape".

[0057] In the holding device 1D of this embodiment, the flow path 30D has two branching and merging sections 31D. In each branching and merging section 31D, the first branching flow path 311D is formed to run along the flow path 30D, and the second branching flow path 312D is formed to connect adjacent first branching flow paths 311D. In this manner, as in the above embodiment, it is possible to improve the uniformity of the in-plane temperature on the main surface of the base 10 or to create a desired temperature difference within the plane.

[0058] <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.

[0059] In the first embodiment described above, the flow path 30 was assumed to have a plurality of branching and merging sections 31, 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.

[0060] In the first embodiment described above, an example is shown in which the first branch channel and the second branch channel face each other, and in the second to fourth embodiments, an example is shown in which the first branch channel is formed along the channel and the second branch channel connects adjacent first branch channels. However, the channel 30 may have one or more branch merging sections from the branch merging section of the first embodiment and the branch merging sections of the second to fourth embodiments. Also, in the branch merging section 31 of the first embodiment, the depth of the second branch channel may be formed to be partially different.

[0061] • In the first embodiment described above, an example was shown in which the first branch channel 311 and the second branch channel 312 are formed to be curved, but the branch channels may also be formed to bend (fold).

[0062] In the above embodiment, the holes 14 and 23 formed in the holding device are 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.

[0063] In the above 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.

[0064] In the above embodiment, an example was shown in which the groove 13 constituting the flow path 30 is formed in the second base 12, but the groove 13 may also be formed in the first base 11, or in both the first base 11 and the second base 12.

[0065] In the above 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.

[0066] 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.

[0067] <Application Example 1> A plate-shaped base having a flow path for a refrigerant inside and a pair of main surfaces, The flow path has at least one branching and merging section, which includes a branching section that branches the flow path into a first branching flow path and a second branching flow path, and a merging section that merges the first branching flow path and the second branching flow path into one. The cross-sectional area of ​​the second branch channel is smaller than the cross-sectional area of ​​the first branch channel. Base. <Application Example 2> The base described in Application Example 1, The aforementioned flow path has a portion that is formed in a spiral shape or bent, The first branch channel is formed along the channel, The second branch channel is characterized in that it is formed to connect adjacent first branch channels. Base. <Application Example 3> A base as described in Application Example 1 or Application Example 2, The first branch channel and the second branch channel are characterized in that they face each other. Base. <Application Example 4> A base described in any one of the examples from Application Example 1 to Application Example 3, The flow path is characterized by having a plurality of branching and merging sections. Base. <Application Example 5> A base described in any one of the examples from Application Example 1 to Application Example 4, The second branch channel is characterized by having a first portion having a predetermined depth and a second portion having a depth different from the depth of the aforementioned portion. Base. <Application Example 6> A holding device, A plate-shaped part having a mounting surface on which an object is placed, A base that supports the plate-like portion, It has, The base is characterized by being the base described in any one of Application Examples 1 to 5. holding device. [Explanation of Symbols]

[0068] 1,1A,1B,1C,1D…Holding device 5…Zygote 10…Base 11a, 11b, 12a, 12b,...base 14, 23… holes 20…Ceramic base material 21… Mounting surface 30, 30A, 30B, 30C, 30D…flow channels 31, 31A, 31B, 31C, 31D2... Branching and merging sections 311, 311A, 311B, 311C, 311D… First branch channel 312, 312A, 312B, 312C, 312D… Second branch channel 313,313A... Branch section 314,314B…Confluence part 315...Island C30…center line C5…Central axis

Claims

1. A plate-shaped base having a flow path for a refrigerant inside and a pair of main surfaces, The flow path has at least one branching and merging section, which includes a branching section that branches the flow path into a first branching flow path and a second branching flow path, and a merging section that merges the first branching flow path and the second branching flow path into one. The cross-sectional area of ​​the second branch channel is smaller than the cross-sectional area of ​​the first branch channel. Base.

2. A base according to claim 1, The aforementioned flow path has a portion that is formed in a spiral shape or bent, The first branch channel is formed along the channel, The second branch channel is characterized in that it is formed to connect adjacent first branch channels. Base.

3. A base according to claim 1, The first branch channel and the second branch channel are characterized in that they face each other. Base.

4. A base according to claim 1, The flow path is characterized by having a plurality of branching and merging sections. Base.

5. A base according to claim 1, The second branch channel is characterized by having a first portion having a predetermined depth and a second portion having a depth different from the depth of the aforementioned portion. Base.

6. A holding device, A plate-shaped part having a mounting surface on which an object is placed, A base that supports the plate-like portion, It has, The base is characterized by being the base described in any one of claims 1 to 5. holding device.

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