Substrate holding member and method for manufacturing the substrate holding member

Abstract

To provide a substrate holding member capable of suppressing deformation of the outer peripheral portion of a substrate and easily adjusting a contact area with the substrate.SOLUTION: A substrate holding member 100 has a ceramic base 110. The upper surface 111 of the ceramic base 110 is provided with an annular projection 152 arranged on the outer periphery of the upper surface 111 and a plurality of projections 156 arranged inside the annular projection 152. An inner peripheral surface 152b of the annular protrusion 152 is an inclined surface that slopes inward toward the bottom.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a substrate holding member for holding a substrate such as a silicon wafer and a method for manufacturing the substrate holding member.

Background Art

[0002] Patent Document 1 discloses an electrostatic chuck for holding a substrate such as a wafer. The electrostatic chuck described in Patent Document 1 includes a base on which the substrate is placed, a plurality of convex portions (protrusions) that protrude from the upper surface of the base and support the substrate, and an annular convex portion (sealing ring) that protrudes annularly from the upper surface of the outer peripheral edge portion of the base and supports the substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the electrostatic chuck described in Patent Document 1, the heights of the plurality of protrusions that are dispersedly arranged inside the sealing ring are the same as the height of the sealing ring. By bringing the substrate into contact with the sealing ring, deformation of the outer peripheral portion of the substrate can be suppressed. However, depending on the width of the sealing ring, the contact area with the substrate may become too large or too small, and heat transfer on the contact surface between the substrate and the sealing ring may not be uniform.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a substrate holding member and a method for manufacturing the same that can suppress deformation of the outer peripheral portion of the substrate, can easily adjust the contact area with the substrate, and as a result, can easily adjust the amount of heat transferred to the substrate between the outer peripheral portion of the substrate and its inner region to equalize the temperature of the substrate.

Means for Solving the Problems

[0006] According to an aspect of the present invention, a ceramic substrate having an upper surface and a lower surface facing the upper surface in the vertical direction, A substrate holding member comprising an electrode embedded in the ceramic substrate or disposed on the lower surface of the ceramic substrate, The aforementioned ceramic substrate is An annular protrusion is arranged on the outer periphery of the ceramic substrate and protrudes above the upper surface of the ceramic substrate, The ceramic substrate comprises a plurality of protrusions arranged inside the annular protrusion and projecting upward above the upper surface of the ceramic substrate, When the cross-section of the annular protrusion is defined as the vertical plane passing through the center of the ceramic substrate and parallel to the vertical direction, In the longitudinal section, within the upper half of the annular protrusion in the vertical direction, the length of the annular protrusion in the direction perpendicular to the vertical direction increases as you move downward from the upper surface of the annular protrusion. small As it becomes thinner, or as it moves downward from the upper surface of the annular protrusion large As soon as, The radially outer circumferential surface of the annular protrusion is an inclined surface that is tilted with respect to the vertical direction. Furthermore, the radial outer surface of the ceramic substrate is an inclined surface that is continuous with the outer surface of the annular protrusion. A substrate holding member is provided, characterized by the following. [Effects of the Invention]

[0007] In the above embodiment, an annular protrusion is provided on the outer periphery of the ceramic substrate, and it contacts the outer periphery of the substrate when the substrate is held. This makes it possible to suppress deformation of the outer periphery of the substrate when the substrate is held on the upper surface of the ceramic substrate. Furthermore, in the vertical cross-section, in at least the upper half of the annular protrusion, the length of the annular protrusion in the direction perpendicular to the vertical direction decreases monotonically or stepwise as it moves downward from the upper surface of the annular protrusion. Alternatively, in the vertical cross-section, in at least the upper half of the annular protrusion, the length of the annular protrusion in the direction perpendicular to the vertical direction increases monotonically or stepwise as it moves downward from the upper surface of the annular protrusion. In these cases, the contact area between the upper surface of the annular protrusion and the substrate can be easily adjusted by performing a trimming process to shorten the length of the annular protrusion and the multiple protrusions in the direction perpendicular to the vertical direction. This makes it possible to suppress localized fluctuations in the amount of heat transferred from the substrate holding member to the substrate in the annular region that contacts the upper surface of the annular protrusion, thereby equalizing the amount of heat transferred from the substrate holding member to the substrate. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view of the substrate holding member 100. [Figure 2] Figure 2 is a schematic diagram illustrating the substrate holding member 100. [Figure 3] Figure 3 is a schematic diagram of electrode 120. [Figure 4] Figures (a) to (e) show the flow of the manufacturing method for the ceramic substrate 110. [Figure 5] Figures (a) to (d) show the flow of another method for manufacturing the ceramic substrate 110. [Figure 6] Figure 6 is an explanatory diagram illustrating the outer peripheral surface 152c of the annular projection 152 of the substrate holding member 100 of Embodiment 2. [Figure 7] Figure 7 is an explanatory diagram illustrating the inner circumferential surface 152b of the annular projection 152 of the substrate holding member 100 of Embodiment 3. [Figure 8] FIG. 8 is an explanatory diagram for explaining the inner peripheral surface 152b of the annular convex portion 152 of the substrate holding member 100 of Example 4. [Figure 9] FIG. 9 is an explanatory diagram for explaining the electrostatic adsorption electrode 124 of the substrate holding member 100 of Example 4. [Figure 10] FIG. 10 is an explanatory diagram for explaining the joining convex portion 114 of the substrate holding member 100 of Example 5. [Figure 11] FIG. 11 is a table summarizing the results of Examples 1 to 5. [Figure 12] FIG. 12 is an explanatory diagram for explaining another shape of the inner peripheral surface 152b of the annular convex portion 152. [Figure 13] FIG. 13 is a flowchart showing a manufacturing method of the substrate holding member 100. [Figure 14] FIG. 14 is an explanatory diagram for explaining the outer peripheral surface 152c of the annular convex portion 152 and the outer peripheral surface 110c of the ceramic base material 110 of the substrate holding member 100 according to a modified example. [Figure 15] FIG. 15 is an explanatory diagram for explaining the inner peripheral surface 152b and the outer peripheral surface 152c of the annular convex portion 152 of the substrate holding member 100 according to a modified example.

BEST MODE FOR CARRYING OUT THE INVENTION

[0009] <Substrate holding member 100> The substrate holding member 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. The substrate holding member 100 according to the present embodiment is a ceramic heater used for heating a semiconductor wafer such as a silicon wafer (hereinafter simply referred to as wafer 10). In the following description, the vertical direction 5 is defined based on the state in which the substrate holding member 100 is installed so as to be usable (the state of FIG. 1). As shown in FIG. 1, the substrate holding member 100 according to the present embodiment includes a ceramic base material 110, an electrode 120, a shaft 130, and a power supply line 140 and includes.

[0010] The ceramic substrate 110 is a circular, plate-shaped component with a diameter of 12 inches (approximately 300 mm), and the wafer 10 to be heated is placed on top of the ceramic substrate 110. In Figure 1, the wafer 10 and the ceramic substrate 110 are shown separated for clarity. As shown in Figure 1, the upper surface 111 of the ceramic substrate 110 is provided with an annular protrusion 152 (hereinafter simply referred to as the annular protrusion 152) and a plurality of protrusions 156. In Figure 1, the number of plurality of protrusions 156 is reduced compared to Figure 2 for clarity. Also, as shown in Figure 2, a first gas channel 164, which will be described later, is formed inside the ceramic substrate 110. The ceramic substrate 110 can be formed from, for example, a ceramic sintered body of aluminum nitride, silicon carbide, alumina, silicon nitride, etc.

[0011] As shown in Figures 1 and 2, the annular projection 152 is an annular projection located on the outer periphery (outer edge) of the upper surface 111 of the ceramic substrate 110, and protrudes upward from the upper surface 111. As shown in Figure 2, when the wafer 10 is placed on the ceramic substrate 110, the upper surface 152a of the annular projection 152 abuts against the lower surface of the wafer 10. In other words, when the wafer 10 is placed on the ceramic substrate 110, the annular projection 152 is positioned to overlap with the wafer 10 in the vertical direction 5. The radially inner side surface 152b of the annular projection 152 (hereinafter referred to as the inner circumferential surface 152b) is an inclined surface that is tilted so that the width of the annular projection 152 increases as it goes downwards. The radially outer side surface 152c of the annular projection 152 (hereinafter referred to as the outer circumferential surface 152c) is not an inclined surface, but a surface perpendicular to the upper surface 111. Multiple protrusions 156 are provided inside the annular protrusion 152 on the upper surface 111 of the ceramic substrate 110. Each of the multiple protrusions 156 is cylindrical in shape. One of the multiple protrusions 156 is positioned approximately at the center of the upper surface 111. The remaining protrusions 156 are arranged on the circumference of four concentric circles that are spaced at equal intervals. Furthermore, the protrusions 156 are spaced at equal intervals on the circumference of each concentric circle. The position and / or number of the protrusions 156 are set appropriately according to the application, action, and function.

[0012] The height of the annular convex portion 152 can be in the range of 5 μm to 2 mm. Similarly, the height of the plurality of convex portions 156 can also be in the range of 5 μm to 2 mm. In the present embodiment, the height of the annular convex portion 152 is the same as the height of the plurality of convex portions 156. In other words, the upper surface 152a of the annular convex portion 152 and the upper surfaces 156a of the plurality of convex portions 156 are flush. In the present specification, the height of the annular convex portion 152 and the height of the plurality of convex portions 156 are defined as the vertical length from the upper surface 111 of the ceramic substrate 110. When the upper surface 111 of the ceramic substrate 110 is not flat, for example, when it has a step, it is defined as the vertical length from the highest position of the upper surface 111 of the ceramic substrate 110.

[0013] The width of the upper surface 152a of the annular convex portion 152 is preferably a constant width and can be 0.1 mm to 10 mm. The surface roughness Ra of the upper surface 152a of the annular convex portion 152 can be 1.6 μm or less. Similarly, the surface roughness Ra of the upper surfaces 156a of the plurality of convex portions 156 can be 1.6 μm or less. The surface roughness Ra of the upper surface 152a of the annular convex portion 152 and the upper surfaces 156a of the plurality of convex portions 156 is preferably 0.4 μm or less, more preferably 0.2 μm or less, and even more preferably 0.1 μm or less.

[0014] The upper surfaces 156a of the plurality of convex portions 156 are preferably circular with a diameter of 0.1 mm to 5 mm. Also, the separation distance between the respective convex portions of the plurality of convex portions 156 can be in the range of 1.5 mm to 30 mm.

[0015] As described above, on the upper surface 111 of the ceramic substrate 110, the multiple protrusions 156 are arranged on the circumference of four concentric circles. As shown in Figure 2, an opening 164a of the first gas channel 164 is formed between the innermost concentric circle on the upper surface 111 where the multiple protrusions 156 are arranged and the second concentric circle from the inside. The first gas channel 164 is a gas channel with an opening 164a and is formed inside the ceramic substrate 110. The first gas channel 164 extends downward from the opening 164a. As will be described later, the lower end of the first gas channel 164 is joined to the upper end of the second gas channel 168 formed inside the shaft 130.

[0016] The first gas channel 164 can be used as a channel for supplying gas to the space (gap) defined by the upper surface 111 of the ceramic substrate 110 and the lower surface of the wafer 10. For example, it can supply heat transfer gas for heat transfer between the wafer 10 and the ceramic substrate 110. As the heat transfer gas, for example, an inert gas such as helium or argon, or nitrogen gas can be used. The heat transfer gas is supplied through the first gas channel 164 at a pressure set within the range of 100 Pa to 40000 Pa. In addition, if process gas enters the gap inside the annular protrusion 152 from the gap between the upper surface 152a of the annular protrusion 152 and the lower surface of the wafer 10, the gas can be exhausted through the first gas channel 164. In this case, the differential pressure between the pressure outside the gap and the pressure inside the gap can be adjusted by adjusting the exhaust pressure. This makes it possible to adsorb the wafer 10 toward the upper surface of the ceramic substrate 110.

[0017] As shown in Figures 1 and 2, an electrode 120 (an example of a heating element of the present invention) is embedded inside the ceramic substrate 110. As shown in Figure 3, the electrode 120 is a metal mesh or foil cut into strips. The outer diameter of the electrode 120 is 298 mm. The electrode 120 is not exposed from the side of the ceramic substrate 110. A terminal portion 121, which is connected to a power supply line 140 (see Figure 1), is provided approximately in the center of the electrode 120. The electrode 120 is formed from a heat-resistant metal (high melting point metal) such as a mesh or foil woven from wire of tungsten (W), molybdenum (Mo), or an alloy containing molybdenum and / or tungsten. The purity of the tungsten and molybdenum is preferably 99% or higher. The thickness of the electrode 120 is 0.15 mm or less. Furthermore, from the viewpoint of increasing the resistance of the electrode 120 and reducing the current consumption of the substrate holding member 100, it is preferable to set the wire diameter to 0.1 mm or less and the thickness of the electrode 120 to 0.1 mm or less. In addition, the width of the strip-shaped electrode 120 is preferably 2.5 mm to 20 mm, and more preferably 5 mm to 15 mm. In this embodiment, the electrode 120 is cut into the shape shown in Figure 3, but the shape of the electrode 120 is not limited to this and can be changed as appropriate. Furthermore, in addition to the electrode 120, or in place of the electrode 120, at least one of the following may be embedded inside the ceramic substrate 110: an electrostatic chuck electrode for attracting the wafer 10 to the upper surface 111 by Coulomb force, and a plasma electrode for generating plasma above the ceramic substrate 110.

[0018] As shown in Figures 1 and 2, a shaft 130 is connected to the lower surface 113 of the ceramic substrate 110. The shaft 130 has a hollow, substantially cylindrical cylindrical portion 131 and a large-diameter portion 132 (see Figure 1) located below the cylindrical portion 131. The large-diameter portion 132 has a larger diameter than the cylindrical portion 131. In the following description, the longitudinal direction of the cylindrical portion 131 is defined as the longitudinal direction 6 of the shaft 130. As shown in Figure 1, in the usage state of the substrate holding member 100, the longitudinal direction 6 of the shaft 130 is parallel to the vertical direction 5.

[0019] Furthermore, a protrusion 114 (hereinafter referred to as the joining protrusion 114) for joining with the shaft 130 can be provided on the lower surface 113 of the ceramic substrate 110 (see Figure 10). The shape of the joining protrusion 114 is preferably the same as the shape of the upper surface of the shaft 130 to be joined, and the diameter of the joining protrusion 114 is preferably 100 mm or less. Joining protrusion 114 The height of the joining projection (height from the bottom surface 113) should be 2 mm or more, and preferably 5 mm or more. There is no particular upper limit on the height, but considering the ease of manufacturing, the height of the joining projection 114 is preferably 20 mm or less. Furthermore, the bottom surface of the joining projection 114 is preferably parallel to the bottom surface 113 of the ceramic substrate 100. The surface roughness Ra of the bottom surface of the joining projection 114 should be 1.6 μm or less. In addition, the surface roughness Ra of the bottom surface of the joining projection 114 is preferably 0.4 μm or less, and more preferably 0.2 μm or less.

[0020] The upper surface of the cylindrical portion 131 is fixed to the lower surface 113 of the ceramic base material 110 (or the lower surface of the joining projection 114 if one is provided). The shaft 130 may be formed from a ceramic sintered body such as aluminum nitride, silicon carbide, alumina, or silicon nitride, similar to the ceramic base material 110. Alternatively, to improve heat insulation, it may be formed from a material with lower thermal conductivity than the ceramic base material 110. Furthermore, an enlarged diameter portion similar to the large diameter portion 132 provided below the cylindrical portion 131 may be provided on the upper surface of the cylindrical portion 131.

[0021] As shown in Figure 2, the shaft 130 has a hollow cylindrical shape, and a through hole extending in the longitudinal direction 6 (see Figure 1) is formed inside it (the region inside the inner diameter). A power supply line 140 for supplying power to the electrode 120 is arranged in the hollow portion (through hole) of the shaft 130. The upper end of the power supply line 140 is electrically connected to a terminal portion 121 (see Figure 3) located in the center of the electrode 120. The power supply line 140 is connected to a heater power supply (not shown). As a result, power is supplied to the electrode 120 via the power supply line 140.

[0022] Furthermore, as shown in Figure 2, a second gas passage 168 extending in the vertical direction 5 is formed in the cylindrical portion 131 of the shaft 130. As described above, the upper end of the second gas passage 168 is connected to the lower end of the first gas passage 164.

[0023] Next, the manufacturing method of the substrate holding member 100 will be described. In the following explanation, the case in which the ceramic substrate 110 and the shaft 130 are formed from aluminum nitride will be used as an example.

[0024] First, the method for manufacturing the ceramic substrate 110 will be described. As shown in Figure 4(a), granulated powder P, mainly composed of aluminum nitride (AlN) powder, is placed in a carbon bed mold 501 and pre-pressed with a punch 502. Preferably, the granulated powder P contains 5 wt% or less of a sintering aid (for example, Y2O3). Next, as shown in Figure 4(b), electrodes 120 cut to a predetermined shape are placed on top of the pre-pressed granulated powder P. The electrodes 120 are positioned parallel to the surface perpendicular to the pressing direction (the bottom surface of the bed mold 501). At this time, pellets of W or Mo may be embedded at the terminal 121 (see Figure 3) of the electrode 120.

[0025] As shown in Figure 4(c), granulated powder P is further added to the bed mold 501 so as to cover the electrode 120, and then pressed and molded with a punch 502. Next, as shown in Figure 4(d), the granulated powder P with the electrode 120 embedded is fired in the pressed state. The pressure applied during firing is preferably 1 MPa or more. It is also preferable to fire at a temperature of 1800°C or higher. Next, as shown in Figure 4(e), a blind hole is drilled up to the electrode 120 in order to form the terminal 121. If a pellet is embedded, a blind hole drilling up to the pellet is sufficient. Furthermore, a through hole is formed which will become part of the first gas flow path 164. This makes it possible to produce a ceramic substrate 110 with the first gas flow path 164 formed inside. In this case, it is preferable to provide a predetermined opening in the electrode 120 in advance so that the electrode 120 is not exposed from the first gas flow path 164.

[0026] Furthermore, the ceramic substrate 110 can also be manufactured by the following method. As shown in Figure 5(a), a binder is added to granulated aluminum nitride powder P and CIP molding is performed, and the resulting disc is processed to produce an aluminum nitride molded body 510. Next, as shown in Figure 5(b), the molded body 510 is degreased to remove the binder.

[0027] As shown in Figure 5(c), a recess 511 for embedding the electrode 120 is formed in the degreased molded body 510. The electrode 120 is placed in the recess 511 of the molded body 510, and another molded body 510 is stacked on top. The recess 511 may be formed in the molded body 510 in advance. Next, as shown in Figure 5(d), the molded bodies 510 stacked with the electrode 120 sandwiched in between are fired while pressed to produce a fired body. The pressure applied during firing is preferably 1 MPa or more. It is also preferable to fire at a temperature of 1800°C or higher. The process after producing the fired body is the same as the process described above, so the explanation is omitted.

[0028] The upper surface 111 of the ceramic substrate 110 formed in this manner is ground and lapped (mirror polished). Furthermore, sandblasting is performed on the upper surface 111 to form a plurality of protrusions 156 and an annular protrusion 152 on the upper surface 111. The height of the annular protrusion 152 and the plurality of protrusions 156 (length in the vertical direction from the upper surface 111) is adjusted according to the temperature evaluation of the substrate holding member, as described later. At this time, the annular protrusion 152 and the plurality of protrusions 156 are processed so that their heights are the same. Although sandblasting is preferred as the processing method for forming the plurality of protrusions 156 and the annular protrusion 152, other processing methods can also be used. The lower surface 113 of the ceramic substrate 110 may be provided with a joining protrusion 114 (see Figure 10) that protrudes from the lower surface 113.

[0029] Next, the manufacturing method of the shaft 130 and the method of joining the shaft 130 to the ceramic substrate 110 will be described. First, granulated aluminum nitride powder P with several wt% binder added is molded under hydrostatic pressure (approximately 1 MPa) to process the molded body into a predetermined shape. At this time, a through hole that will become the second gas passage 168 is formed in the molded body. The outer diameter of the shaft 130 is approximately 30 mm to 100 mm. A flange portion 133 having a diameter larger than the outer diameter of the cylindrical portion 131 may be provided on the end face of the cylindrical portion 131 of the shaft 130 (see Figure 10). The length of the cylindrical portion 131 can be, for example, 50 mm to 500 mm. After processing the molded body into a predetermined shape, the molded body is fired in a nitrogen atmosphere. For example, it is fired at a temperature of 1900°C for 2 hours. Then, the shaft 130 is formed by processing the sintered body into a predetermined shape after firing. The upper surface of the cylindrical portion 131 and the lower surface 113 of the ceramic substrate 110 can be fixed by diffusion bonding at a temperature of 1600°C or higher and a uniaxial pressure of 1 MPa or higher. In this case, the surface roughness Ra of the lower surface 113 of the ceramic substrate 110 is preferably 0.4 μm or less, and more preferably 0.2 μm or less. Alternatively, the upper surface of the cylindrical portion 131 and the lower surface 113 of the ceramic substrate 110 can also be bonded using a bonding agent. As a bonding agent, for example, an AlN bonding paste with 10 wt% Y2O3 added can be used. For example, the above AlN bonding paste can be applied to the interface between the upper surface of the cylindrical portion 131 and the lower surface 113 of the ceramic substrate 110 to a thickness of 15 μm, and the bonding can be achieved by heating at a temperature of 1700°C for 1 hour while applying a force of 5 kPa in a direction perpendicular to the upper surface 111 (the longitudinal direction of the shaft 130 6). Alternatively, the upper surface of the cylindrical portion 131 and the lower surface 113 of the ceramic base material 110 can be fixed together by screwing, brazing, or the like. [Examples]

[0030] The present invention will be further described below using Examples 1 to 5. However, the present invention is not limited to the examples described below. Figure 11 shows a table summarizing the results of Examples 1 to 5.

[0031] [Example 1] The substrate holding member 100 of Example 1 (see Figure 2) will now be described. In Example 1, a ceramic substrate 110 with a diameter of 310 mm and a thickness of 25 mm was fabricated using the above-described manufacturing method, with aluminum nitride (AlN) to which 5 wt% of a sintering aid (Y2O3) had been added as the raw material. As the electrode 120, a molybdenum mesh (wire diameter 0.1 mm, mesh size #50, plain weave) was cut into the shape shown in Figure 3, and such an electrode 120 was embedded in the ceramic substrate 110.

[0032] An annular projection 152 with an inner diameter of 278 mm, an outer diameter of 298 mm, a width of 10 mm, and a height of 200 μm from the top surface 111 was formed on the upper surface 111 of the ceramic substrate 110. The width of the upper surface 152a of the annular projection 152 is 1 mm. The vertical cross-sectional shape (the cross-sectional shape of the vertical plane passing through the center of the ceramic substrate 110) of the inner circumferential surface 152b of the annular projection 152 is linear. Furthermore, 1096 cylindrical projections 156 with a diameter of 1 mm and a height of 200 μm from the top surface 111 were formed on the upper surface 111 of the ceramic substrate 110. As described above, the multiple projections 156 are arranged concentrically, and the distance between each projection is in the range of 10 mm to 20 mm. In this specification, the area ratio S / Sp of the area S of the upper surface 152a of the annular protrusion 152 to the sum of the areas Sp of the upper surfaces 156 of the multiple protrusions 156 is referred to as the rib-pin area ratio. The rib-pin area ratio S / Sp of the substrate holding member 100 in Example 1 was 1.08.

[0033] In the substrate holding member 100 of Example 1, the height of the annular protrusion 152 is 200 μm, and the height of the multiple protrusions 156 is 200 μm. In other words, the height of the annular protrusion 152 and the height of the multiple protrusions 156 are the same. To put it another way, the vertical position (height position) of the upper surface 152a of the annular protrusion 152 is the same as the vertical position (height position) of the upper surface 156a of the protrusion 156. The surface roughness Ra of the upper surface 152a of the annular protrusion 152 and the upper surface 156a of the protrusion 156 were both set to 0.4 μm.

[0034] The diameter of the opening 164a of the first gas flow path 164 is 3 mm. The center of the opening 164a is located 30 mm from the center of the ceramic substrate 110.

[0035] A substrate holding member 100 of this shape was installed in the process chamber. Argon gas was supplied into the process chamber as the process gas at a pressure of 26600 Pa (200 Torr). Furthermore, the argon gas was adjusted to a pressure of 6650 Pa (50 Torr) through the first gas flow path 164.

[0036] The temperature of the substrate holding member 100 was then evaluated using the following procedure. First, a silicon wafer for temperature evaluation was placed on the ceramic substrate 110, and an external power supply (not shown) was connected to the electrode 120 of the substrate holding member 100. Process gas and heat transfer gas were introduced at the above pressure, and the output power of the external power supply was adjusted so that the temperature of the upper surface of the silicon wafer was approximately 400°C in a steady state. After that, the temperature distribution of the silicon wafer for temperature evaluation, in a 298 mm diameter area excluding the area 1 mm from the outer edge, was measured using an infrared camera. The difference between the highest and lowest temperatures in the 298 mm diameter area of ​​the silicon wafer for temperature evaluation was defined as the temperature difference Δ. In addition, it was evaluated whether localized high-temperature areas (heat spots) or localized low-temperature areas (cold spots) occurred at positions overlapping the annular protrusion 152 in the vertical direction on the silicon wafer for temperature evaluation. It was determined that a heat spot had occurred if there was an area that was 3.0°C or more hotter than the average temperature of the silicon wafer for temperature evaluation. Similarly, if there was a region that was 3.0°C or more colder than the average temperature of the silicon wafer used for temperature evaluation, it was determined that a cold spot had occurred. The silicon wafer used for temperature evaluation was a 300 mm diameter silicon wafer with a 30 μm thick blackbody film coated on its top surface. A blackbody film is a film with an emissivity (radiative efficiency) of 90% or more, and can be formed, for example, by coating it with a blackbody paint mainly composed of carbon nanotubes.

[0037] When the temperature distribution of the silicon wafer used for temperature evaluation was evaluated, the temperature difference Δ was -6.5°C. In addition, a cold spot occurred in a part of the annular region of the silicon wafer used for temperature evaluation that overlapped with the annular protrusion 152 in the vertical direction. Note that a negative temperature difference Δ indicates that the temperature on the outer side is lower than the temperature on the inner side. Conversely, a positive temperature difference Δ indicates that the temperature on the outer side is higher than the temperature on the inner side.

[0038] Next, the upper surface 152a of the annular protrusion 152 and the upper surfaces 156a of the multiple protrusions 156 were modified by removing 30 μm. As a result, the height of both the annular protrusion 152 and the multiple protrusions 156 became 170 μm. The rib-pin area ratio S / Sp at this time was 2.54. In this case, when the temperature distribution of the silicon wafer for temperature evaluation was evaluated in the same manner as described above, the temperature difference Δ was -3.5°C, and the absolute value of the temperature difference Δ was reduced compared to before the modification.

[0039] Furthermore, the upper surface 152a of the annular protrusion 152 and the upper surface 156a of the multiple protrusions 156 were modified by removing 10 μm. As a result, the height of both the annular protrusion 152 and the multiple protrusions 156 became 160 μm. The rib-pin area ratio S / Sp at this time was 3.02. In this case, when the temperature distribution of the silicon wafer for temperature evaluation was evaluated in the same manner as described above, the temperature difference Δ was -2.5°C, and the absolute value of the temperature difference Δ was reduced to 3°C or less. At this time, no cold spots or hot spots occurred in a part of the annular region of the silicon wafer for temperature evaluation that overlapped with the annular protrusion 152 in the vertical direction.

[0040] [Example 2] The substrate holding member 100 of Example 2 is the same as the substrate holding member 100 of Example 1, except that the shape of the annular projection 152 is different. As shown in Figure 6, the outer peripheral surface 152c of the annular projection 152 of the substrate holding member 100 of Example 2 is an inclined surface that is tilted so that the width of the annular projection 152 decreases as it goes downwards. The vertical cross-sectional shape (cross-sectional shape of the vertical plane passing through the center of the ceramic substrate 110) of the outer peripheral surface 152c of the annular projection 152 is a straight line. The dimensions of the annular projection 152 at the top surface 152a are an inner diameter of 294 mm, an outer diameter of 308 mm, and a width of 7 mm, and the height from the top surface 111 is 200 μm. Since the outer diameter of the ceramic substrate 110 is 298 mm, the top surface 152a of the annular projection 152 protrudes 5 mm radially outward from the ceramic substrate 110. Since the height of the multiple protrusions 156 is 200 μm, the height of the annular protrusion 152 and the height of the multiple protrusions 156 are the same. The rib-to-pin area ratio S / Sp of the substrate holding member 100 in Example 2 was 8.43.

[0041] A substrate holding member 100 of this shape was installed in a process chamber, and the process gas pressure and argon gas flow rate were adjusted to the same pressure as in Example 1. Then, the temperature of the substrate holding member 100 was evaluated using the same procedure as in Example 1, and the temperature difference Δ was +4.2°C, indicating that the temperature distribution of the silicon wafer used for temperature evaluation showed that the temperature on the outer side was higher than the temperature on the inner side. In addition, a heat spot occurred in a part of the annular region of the silicon wafer used for temperature evaluation that overlapped with the annular protrusion 152 in the vertical direction.

[0042] Next, the upper surface 152a of the annular protrusion 152 and the upper surface 156a of the multiple protrusions 156 were modified by removing 30 μm. As a result, the height of both the annular protrusion 152 and the multiple protrusions 156 became 170 μm. The rib-pin area ratio S / Sp at this time was 7.51. In this case, when the temperature distribution of the silicon wafer for temperature evaluation was evaluated in the same manner as described above, the temperature difference Δ was +2.7°C, and the absolute value of the temperature difference Δ was reduced to 3°C or less, making the absolute value of the temperature difference Δ smaller than before the modification. Furthermore, no cold spots or hot spots occurred in the part of the annular region of the silicon wafer for temperature evaluation that overlapped with the annular protrusion 152 in the vertical direction.

[0043] [Example 3] The substrate holding member 100 of Example 3 is the same as the substrate holding member 100 of Example 1, except that the shape of the annular projection 152 is different. As shown in Figure 7, the inner circumferential surface 152b of the annular projection 152 of the substrate holding member 100 of Example 3 is an inclined surface that is tilted so that the width of the annular projection 152 increases as it goes downwards. The vertical cross-sectional shape (cross-sectional shape of the vertical plane passing through the center of the ceramic substrate 110) of the inner circumferential surface 152b of the annular projection 152 is a downwardly convex quadratic curve shape. The dimensions of the annular projection 152 at the top surface 152a are an inner diameter of 278 mm, an outer diameter of 298 mm, and a width of 1 mm, and the height from the top surface 111 is 200 μm. Since the height of the multiple projections 156 is 200 μm, the height of the annular projection 152 and the height of the multiple projections 156 are the same. The rib-to-pin area ratio S / Sp of the substrate holding member 100 in Example 3 was 1.08, similar to that of the substrate holding member 100 in Example 1.

[0044] A substrate holding member 100 of this shape was installed in a process chamber, and the process gas pressure and argon gas flow rate were adjusted to the same pressure as in Example 1. Then, the temperature of the substrate holding member 100 was evaluated using the same procedure as in Example 1, and the temperature difference Δ was -4.5°C, indicating that the temperature distribution of the silicon wafer used for temperature evaluation showed that the temperature on the outer side was lower than the temperature on the inner side. In addition, a cold spot occurred in a part of the annular region of the silicon wafer used for temperature evaluation that overlapped with the annular protrusion 152 in the vertical direction.

[0045] Next, the upper surface 152a of the annular protrusion 152 and the upper surface 156a of the multiple protrusions 156 were modified by removing 24 μm. As a result, the height of both the annular protrusion 152 and the multiple protrusions 156 became 176 μm. The rib-pin area ratio S / Sp at this time was 1.68. In this case, when the temperature distribution of the silicon wafer for temperature evaluation was evaluated in the same manner as described above, the temperature difference Δ was -1.8°C, and the absolute value of the temperature difference Δ was reduced to 3°C or less, making the absolute value of the temperature difference Δ smaller than before the modification. Furthermore, no cold spots or hot spots occurred in the part of the annular region of the silicon wafer for temperature evaluation that overlapped with the annular protrusion 152 in the vertical direction.

[0046] [Example 4] The substrate holding member 100 of Example 4 is the same as the substrate holding member 100 of Example 1, except that the shape of the annular protrusion 152 is different, the height of the annular protrusion 152 and the multiple protrusions 156 is 30 μm, and the electrostatic adsorption electrode 124 shown in Figure 9 is embedded in the ceramic substrate 110 instead of the electrode 120 shown in Figure 3. As shown in Figure 9, the electrostatic adsorption electrode 124 consists of two semicircular electrodes 124a and 124b arranged facing each other with a predetermined distance between them, and has an overall substantially circular shape. The outer diameter of the electrostatic adsorption electrode 124 is 292 mm. In Example 4, a voltage of +500 V was applied to electrode 124a and -500 V to electrode 124b, and the wafer 10 was electrostatically adsorbed.

[0047] As shown in Figure 8, the inner circumferential surface 152b of the annular projection 152 of the substrate holding member 100 in Example 4 is an inclined surface that is tilted so that the width of the annular projection 152 increases as it goes downwards. The longitudinal cross-sectional shape (cross-sectional shape of the vertical plane passing through the center of the ceramic substrate 110) of the inner circumferential surface 152b of the annular projection 152 is a convex quadratic curve shape. The dimensions of the annular projection 152 at the top surface 152a are an inner diameter of 296 mm, an outer diameter of 298 mm, and a width of 1 mm, and the height from the top surface 111 is 30 μm. Since the height of the multiple projections 156 is 30 μm, the height of the annular projection 152 and the height of the multiple projections 156 are the same. The rib-pin area ratio S / Sp of the substrate holding member 100 in Example 4 was 1.08, the same as that of the substrate holding member 100 in Example 1.

[0048] In the substrate holding member 100 of Example 4, approximately 500W of heat is supplied from the plasma formed above the substrate holding member 100 by a high-frequency power supply (not shown), and the substrate holding member 100 The heat was absorbed by a cooling plate installed on the back surface 113. In Example 8, the pressure inside the process chamber was exhausted to 1 Pa or less, and helium gas was flowed through the first gas channel 164. The gas flow rate of the helium gas was adjusted so that the pressure of the helium gas flowing through the first gas channel 164 was 1330 Pa (10 Torr). Then, the temperature of the substrate holding member 100 was evaluated using the same procedure as in Example 1, and the temperature difference Δ was -3.8°C, indicating that the temperature distribution of the silicon wafer used for temperature evaluation showed that the temperature on the outer side was lower than the temperature on the inner side. In addition, a cold spot occurred in a part of the annular region of the silicon wafer used for temperature evaluation that overlapped with the annular protrusion 152 in the vertical direction.

[0049] Next, the upper surface 152a of the annular protrusion 152 and the upper surfaces 156a of the multiple protrusions 156 were modified by removing 3 μm. As a result, the height of both the annular protrusion 152 and the multiple protrusions 156 became 27 μm. The rib-pin area ratio S / Sp at this time was 4.13. In this case, when the temperature distribution of the silicon wafer for temperature evaluation was evaluated in the same manner as described above, the temperature difference Δ was -0.9°C, and the absolute value of the temperature difference Δ was reduced to 3°C or less, making the absolute value of the temperature difference Δ smaller than before the modification. No cold spots or hot spots occurred in the part of the annular region of the silicon wafer for temperature evaluation that overlapped with the annular protrusion 152 in the vertical direction. Furthermore, because the vertical cross-sectional shape of the inner circumferential surface 152b of the annular protrusion 152 was a convex quadratic curve shape, it was possible to significantly change the rib-pin area ratio S / Sp with less material removal compared to Examples 1 to 3, and to keep the change in the external dimensions of the substrate holding member 100 for temperature control to a minimum.

[0050] [Example 5] As shown in Figure 10, the substrate holding member 100 of Example 5 is the same as the substrate holding member 100 of Example 2, except that a joining projection 114 with a diameter of 80 mm and a height of 3 mm is provided in the center of the lower surface 113 of the ceramic substrate 110. The outer diameter of the cylindrical portion 131 of the shaft 130 is 70 mm, the inner diameter is 50 mm, and the length of the cylindrical portion 131 in the longitudinal direction is 170 mm. A flange portion 133 with a diameter of 80 mm and a thickness of 15 mm is provided on the upper end face of the cylindrical portion 131. The joining projection 114 and the flange portion 133 are then diffusion bonded.

[0051] As described above, in Example 5, the shapes of the annular projection 152 and the multiple projections 156 of the substrate holding member 100 are the same as in Example 2. Therefore, similar to Example 2, the rib-to-pin area ratio S / Sp of the substrate holding member 100 in Example 5 was 8.43.

[0052] A substrate holding member 100 of this shape was installed in a process chamber, and the process gas pressure and argon gas flow rate were adjusted to the same pressure as in Example 2. Then, the temperature of the substrate holding member 100 was evaluated using the same procedure as in Example 2, and the temperature difference Δ was +7.5°C, indicating that the temperature distribution of the silicon wafer used for temperature evaluation showed that the temperature on the outer side was higher than the temperature on the inner side. In addition, a heat spot occurred in a part of the annular region of the silicon wafer used for temperature evaluation that overlapped with the annular protrusion 152 in the vertical direction.

[0053] Next, the upper surface 152a of the annular protrusion 152 and the upper surfaces 156a of the multiple protrusions 156 were modified by removing 50 μm. As a result, the height of both the annular protrusion 152 and the multiple protrusions 156 became 150 μm. The rib-pin area ratio S / Sp at this time was 6.89. In this case, when the temperature distribution of the silicon wafer for temperature evaluation was evaluated in the same manner as described above, the temperature difference Δ was +2.7°C, and the absolute value of the temperature difference Δ was reduced to 3°C or less, making the absolute value of the temperature difference Δ smaller than before the modification. Furthermore, no cold spots or hot spots occurred in the part of the annular region of the silicon wafer for temperature evaluation that overlapped with the annular protrusion 152 in the vertical direction.

[0054] <Effects of the Embodiment> In the above embodiments and examples 1 to 5, the substrate holding member 100 comprises a ceramic substrate 110. The upper surface 111 of the ceramic substrate 110 is provided with an annular projection 152 positioned on the outer periphery of the upper surface 111 and projecting upward from the upper surface 111, and a plurality of projections 156 positioned inside the annular projection 152 and projecting upward from the upper surface 111. It also comprises an electrode 120 (or electrostatic adsorption electrode 124) embedded in the ceramic substrate 110.

[0055] Since the annular projection 152 is provided on the outer periphery of the ceramic substrate 110, deformation of the outer periphery of the wafer 10 can be suppressed when the wafer 10 is adsorbed toward the upper surface of the ceramic substrate 110. Furthermore, gas can be prevented from entering the gap surrounded by the upper surface 111 of the substrate holding member 110, the annular projection 152, and the wafer 10 from the outside of the annular projection 152. Alternatively, gas can be prevented from flowing out from the inside to the outside of the annular projection 152. In this way, when the annular projection 152 functions as a barrier to suppress gas outflow and inflow, a larger contact area between the upper surface 152a of the annular projection 152 and the lower surface of the wafer 10 is more effective. However, if the contact area between the upper surface 152a of the annular projection 152 and the lower surface of the wafer 10 is large, as described above, the heat transferred from the substrate holding member 100 to the wafer 10 may be locally concentrated in the annular region that contacts the upper surface 152a of the annular projection 152. Conversely, if the contact area between the upper surface 152a of the annular protrusion 152 and the lower surface of the wafer 10 becomes too small, the heat transferred from the substrate holding member 100 to the wafer 10 may be locally reduced in the annular region that contacts the upper surface 152a of the annular protrusion 152.

[0056] In the substrate holding member 100 of Examples 1, 3, and 4, the length of the annular protrusion 152 in the vertical cross-sectional shape (cross-sectional shape of the vertical plane passing through the center of the ceramic substrate 110) in the direction perpendicular to the vertical direction increases monotonically from the upper surface 152a of the annular protrusion 152 downwards. Because the annular protrusion 152 has this shape, by performing a removal process to remove the upper surface 152a of the annular protrusion 152 and lowering the height of the annular protrusion 152, the area of ​​the upper surface 152a of the annular protrusion 152 can be increased compared to before the removal process. At this time, the removal process is also performed on multiple protrusions 156 so that they are the same height as the annular protrusion 152. By performing this removal process, the ratio S / Sp (rib-pin area ratio S / Sp) of the contact area S between the upper surface 152a of the annular protrusion 152 and the lower surface of the wafer 10 held by the substrate holding member 100 to the total contact area Sp between the upper surface 156a of the multiple protrusions 156 and the lower surface of the wafer 10 held by the substrate holding member 100 can be made larger than before the removal process. In this way, by removing the annular protrusion 152 and the multiple protrusions 156, the rib-pin area ratio S / Sp can be easily adjusted to be larger. As described above, the contact area between the upper surface 152a of the annular protrusion 152 and the lower surface of the wafer 10 may become too small, and the heat transferred from the substrate holding member 100 to the wafer 10 may be locally reduced in the annular region that contacts the upper surface 152a of the annular protrusion 152. By adjusting the rib-pin area ratio S / Sp to be large, it is possible to suppress the localized reduction in the amount of heat transferred from the substrate holding member 100 to the wafer 10 in the annular region that contacts the upper surface 152a of the annular protrusion 152. This makes it possible to equalize the amount of heat transferred from the substrate holding member 100 to the wafer 10.

[0057] As shown in Figure 12, the length of the annular protrusion 152 in the vertical cross-sectional shape (the cross-sectional shape of the vertical plane passing through the center of the ceramic substrate 110) in the direction perpendicular to the vertical direction may increase gradually from the upper surface 152a of the annular protrusion 152 downwards. In this case as well, the same effect can be achieved as when the length of the annular protrusion 152 in the vertical cross-sectional shape increases monotonically from the upper surface 152a of the annular protrusion 152 downwards. The length does not need to increase monotonically or gradually as it moves downwards. As shown in Figure 12, the length of the annular protrusion 152 in the vertical cross-sectional shape, in the direction perpendicular to the vertical direction, only needs to increase monotonically or gradually as it moves downwards from the upper surface 152a of the annular protrusion 152, at least in the upper half of the vertical direction. In this case as well, the same effect can be achieved as when the length of the annular protrusion 152 in the vertical cross-sectional shape, in the direction perpendicular to the vertical direction, increases monotonically or gradually as it moves downwards from the upper surface 152a of the annular protrusion 152, over the entire vertical range.

[0058] In the substrate holding member 100 of Examples 2 and 5, the length of the annular protrusion 152 in the vertical cross-sectional shape (cross-sectional shape of the vertical plane passing through the center of the ceramic substrate 110) decreases monotonically from the upper surface 152a of the annular protrusion 152 downwards. Because the annular protrusion 152 has this shape, by performing a removal process to remove the upper surface 152a of the annular protrusion 152 and lowering the height of the annular protrusion 152, the area of ​​the upper surface 152a of the annular protrusion 152 can be reduced compared to before the removal process. At this time, the removal process is also performed on multiple protrusions 156 so that they are all the same height as the annular protrusion 152. This makes it possible to reduce the ratio S / Sp (rib-pin area ratio S / Sp) of the contact area S between the upper surface 152a of the annular protrusion 152 and the lower surface of the wafer 10 held by the substrate holding member 100 to the sum Sp of the contact areas Sp between the upper surfaces 156a of the multiple protrusions 156 and the lower surface of the wafer 10 held by the substrate holding member 100, compared to before the removal process. In this way, by removing the annular protrusion 152 and the multiple protrusions 156, the rib-pin area ratio S / Sp can be easily adjusted to be smaller. As described above, there are cases where the contact area between the upper surface 152a of the annular protrusion 152 and the lower surface of the wafer 10 becomes too large, and the amount of heat transferred from the substrate holding member 100 to the wafer 10 becomes locally large in the annular region that contacts the upper surface 152a of the annular protrusion 152. By adjusting the rib-pin area ratio S / Sp to be small, it is possible to suppress the localized increase in the amount of heat transferred from the substrate holding member 100 to the wafer 10 in the annular region that contacts the upper surface 152a of the annular protrusion 152. This makes it possible to equalize the amount of heat transferred from the substrate holding member 100 to the wafer 10.

[0059] Furthermore, the length of the annular projection 152 in the vertical cross-sectional shape, in the direction perpendicular to the vertical direction, may decrease gradually from the upper surface 152a of the annular projection 152 downwards. Alternatively, the length of the annular projection 152 in the vertical cross-sectional shape, in the direction perpendicular to the vertical direction, may decrease monotonically or gradually from the upper surface 152a of the annular projection 152 downwards, at least in the upper half of the vertical direction.

[0060] As in Example 4, when using the electrostatic adsorption electrode 124, it is preferable that the maximum vertical height of the annular protrusion 152 and the multiple protrusions 156 from the upper surface 111 is 30 μm or less. By making the maximum vertical height of the annular protrusion 152 and the multiple protrusions 156 from the upper surface 111 30 μm or less, electrostatic adsorption can be performed efficiently. In this case, it is preferable that the rib-pin area ratio S / Sp is 0.3 or more and 25 or less. If the rib-pin area ratio S / Sp is less than 0.3, the width of the upper surface 152a of the annular protrusion 152 becomes too narrow, which may cause helium gas to leak into the process chamber and make it impossible to maintain the pressure inside the process chamber at 1 Pa. Also, if the rib-pin area ratio S / Sp is greater than 25, the width of the upper surface 152a of the annular protrusion 152 becomes too wide, which increases the risk that the electrostatic adsorption force will remain for a long time after the end of the process and the substrate will not be able to be transported.

[0061] When using the electrode 120 as a heater electrode, as in Examples 1 to 3 and 5, it is preferable that the maximum height of the annular protrusion 152 and the multiple protrusions 156 in the vertical direction from the upper surface 111 is 500 μm or less. By limiting the maximum vertical height from the electrode 120 to 500 μm or less, the heat generated at the electrode 120 can be efficiently transferred to the wafer 10. In this case, the rib-pin area ratio S / Sp is preferably between 5.0 and 60. When the rib-pin area ratio S / Sp is less than 5.0, the width of the upper surface 152a of the annular protrusion 152 becomes too narrow, reducing the pressure difference between the pressure in the process chamber and the pressure in the space between the substrate and the upper surface, increasing the risk of vacuum adsorption failure. Also, when the rib-pin area ratio S / Sp is greater than 60, the width of the upper surface 152a of the annular protrusion 152 becomes too wide, increasing the substrate temperature directly above the annular protrusion 152 and increasing the risk of a heat spot.

[0062] Next, the adjustment of the height of the annular projection 152 and the height of the multiple projections 156 when manufacturing the substrate holding member 100 will be explained with reference to Figure 13.

[0063] First, a substrate holding member 100 is prepared (S10). As described above, the substrate holding member 100 comprises a ceramic substrate 110 and an electrode 120 (or electrostatic adsorption electrode 124) embedded in the ceramic substrate 110. The upper surface 111 of the ceramic substrate 110 is provided with an annular projection 152 positioned on the outer periphery of the upper surface 111 and projecting upward from the upper surface 111, and a plurality of projections 156 positioned inside the annular projection 152 and projecting upward from the upper surface 111. As in Examples 1, 3, and 4, the length of the annular projection 152 in the vertical cross-sectional shape, in the direction perpendicular to the vertical direction, increases monotonically or stepwise from the upper surface 152a of the annular projection 152 downwards in at least the upper half in the vertical direction. Alternatively, as in Examples 2 and 5, the length of the annular projection 152 in the vertical cross-sectional shape, in the direction perpendicular to the vertical direction, decreases monotonically or stepwise from the upper surface 152a of the annular projection 152 downwards, at least in the upper half of the vertical direction.

[0064] Next, with the silicon wafer for temperature evaluation held in the substrate holding member 100A, the temperature distribution of the silicon wafer for temperature evaluation is measured (Figure 13: S20). Then, according to the measured temperature distribution, the entire upper surface 152a of the annular protrusion 152 is modified to reduce the height of the annular protrusion 152 (S30). Also, according to the measured temperature distribution, the height of all of the multiple protrusions 156 is modified to reduce the height (S40). Note that the modification of the upper surface 152a of the annular protrusion 152 (S30) and the modification of the upper surface 156a of the multiple protrusions 156 (S40) may be performed in either order or simultaneously. In either case, the modification is performed so that the height of the annular protrusion 152 and the height of all of the multiple protrusions 156 are the same. In this way, the rib-pin area ratio S / Sp can be adjusted by modifying the height of the annular protrusion 152 and the multiple protrusions 156 based on the results of the temperature distribution measurement of the silicon wafer for temperature evaluation. As a result, as described above, the heat transferred from the substrate holding member 100 to the wafer 10 is suppressed from becoming locally larger or smaller in the annular region that contacts the upper surface 152a of the annular protrusion 152, thereby enabling uniform heating.

[0065] <Change form> The embodiments described above are merely illustrative and can be modified as appropriate. For example, the shape and dimensions of the ceramic substrate 110 and the shaft 130 are not limited to those of the embodiments described above and can be modified as appropriate. The height, width, and other dimensions of the annular projection 152, the longitudinal cross-sectional shape, and the surface roughness Ra of the upper surface can be modified as appropriate. For example, as shown in Figure 14, the outer circumferential surface 110c of the ceramic substrate 110 may be an inclined surface continuous with the outer circumferential surface 152c of the annular projection 152. Also, as shown in Figure 15, both the inner circumferential surface 152b and the outer circumferential surface 152c of the annular projection 152 may be inclined surfaces.

[0066] The height of the multiple protrusions 156, the shape of the upper surface 156a, and the magnitude of the surface roughness Ra of the upper surface 156a can be changed as appropriate. For example, the shape of the upper surface 156a of the multiple protrusions 156 is not necessarily circular. It is not necessary, and it can be any shape. However, even in that case, it is preferable that it has an area equivalent to that of a circle with a diameter of 0.1 mm to 5 mm. Furthermore, although in the above description the multiple protrusions 156 were arranged to be distributed in a concentric pattern, the present invention is not limited to such an embodiment. For example, the multiple protrusions 156 may be arranged continuously in a grid pattern so as to be distributed at the vertices of an equilateral triangle or a regular square, or the multiple protrusions 156 may be arranged to be distributed at random positions. Even in that case, it is preferable that the spacing between each of the multiple protrusions 156 is in the range of 1.5 mm to 30 mm.

[0067] In the above embodiment, the electrode 120 was made of molybdenum, tungsten, or an alloy containing molybdenum and / or tungsten, but the present invention is not limited to such embodiments. For example, metals or alloys other than molybdenum and tungsten can also be used. Furthermore, although the electrode 120 was a heater electrode as a heating element, the electrode 120 does not necessarily have to be a heater electrode as a heating element, and may be, for example, an electrostatic adsorption electrode or a high-frequency electrode.

[0068] In the above embodiment, the substrate holding member 100 was equipped with electrodes (electrodes 120 or electrostatic adsorption electrodes 124) embedded in the ceramic substrate 110. However, the present invention is not limited to such embodiments, and the electrodes do not have to be embedded in the ceramic substrate 110 of the substrate holding member 100. For example, the electrodes 120 may be attached to the back surface 113 of the ceramic substrate 110.

[0069] In the above embodiment, the substrate holding member 100 was equipped with a shaft 130, but the present invention is not limited to such an embodiment, and the substrate holding member 100 does not necessarily have to be equipped with a shaft 130. Furthermore, even if the substrate holding member 100 is equipped with a shaft 130, a second gas passage 168 extending in the vertical direction 5 is not required to be formed in the cylindrical portion 131 of the shaft 130. For example, instead of the second gas passage 168, a separate gas pipe can be provided in the hollow region of the cylindrical portion 131 (the region where the power supply line 140 is provided).

[0070] Although embodiments and modified versions of the invention have been described above, the technical scope of the present invention is not limited to the scope described above. It will be obvious to those skilled in the art that various modifications or improvements can be made to the above embodiments. It is also clear from the claims that such modified or improved forms may be included in the technical scope of the present invention.

[0071] The order in which each process in the manufacturing method shown in the specification and drawings is executed is not specifically defined, and unless the output of a previous process is used in a later process, the processes can be executed in any order. Even if phrases such as "first," and "next," are used for convenience, this does not mean that the processes must be performed in that order. [Explanation of symbols]

[0072] 100 Substrate holding member 110 Ceramic substrate 120 electrodes 130 shaft 140 Feed line 152 Annular protrusion 156 Multiple protrusions

Claims

1. A ceramic substrate having an upper surface and a lower surface that is opposite to the upper surface in the vertical direction, A substrate holding member comprising an electrode embedded in the ceramic substrate or disposed on the lower surface of the ceramic substrate, The aforementioned ceramic substrate is An annular protrusion is arranged on the outer periphery of the ceramic substrate and protrudes above the upper surface of the ceramic substrate, The ceramic substrate comprises a plurality of protrusions arranged inside the annular protrusion and projecting upward above the upper surface of the ceramic substrate, When the cross-section of the annular protrusion is defined as the vertical plane passing through the center of the ceramic substrate and parallel to the vertical direction, In the longitudinal section, within the upper half of the annular protrusion in the vertical direction, the length of the annular protrusion in the direction perpendicular to the vertical direction decreases as it moves downward from the upper surface of the annular protrusion, or increases as it moves downward from the upper surface of the annular protrusion. The radially outer circumferential surface of the annular protrusion is an inclined surface that is tilted with respect to the vertical direction. A substrate holding member characterized in that the radial outer surface of the ceramic substrate is an inclined surface continuous with the outer surface of the annular protrusion.

2. The electrode is an electrostatic electrode for electrostatically adsorbing the substrate onto the ceramic substrate. When the area of ​​the upper surface of the annular protrusion is S, the sum of the areas of the upper surfaces of the plurality of protrusions is Sp, and the maximum height of the annular protrusion and the plurality of protrusions in the vertical direction from the upper surface of the ceramic substrate is H (μm), 0.3 ≤ S / Sp ≤ 25 and, H ≤ 30 The substrate holding member according to claim 1.

3. The electrode is a heating element for heating a substrate held in the ceramic substrate. When the area of ​​the upper surface of the annular protrusion is S, the sum of the areas of the upper surfaces of the plurality of protrusions is Sp, and the maximum height of the annular protrusion and the plurality of protrusions in the vertical direction from the upper surface of the ceramic substrate is H (μm), 5.0 ≤ S / Sp ≤ 60 and, H ≤ 500 The substrate holding member according to claim 1.

4. Furthermore, the ceramic substrate is provided with a cylindrical shaft joined to the lower surface, The substrate holding member according to claim 1 or 3, wherein the electrode embedded in the ceramic substrate or positioned on the lower surface of the ceramic substrate is a heating element.

5. A method for manufacturing a substrate holding member, A substrate holding member, A ceramic substrate having an upper surface and a lower surface that is opposite to the upper surface in the vertical direction, The invention comprises an electrode embedded in the ceramic substrate or positioned on the lower surface of the ceramic substrate. The aforementioned ceramic substrate is An annular protrusion is arranged on the outer periphery of the ceramic substrate and protrudes above the upper surface of the ceramic substrate, The ceramic substrate comprises a plurality of protrusions arranged inside the annular protrusion and projecting upward above the upper surface of the ceramic substrate, When the cross-section of the annular protrusion is defined as the vertical plane passing through the center of the ceramic substrate and parallel to the vertical direction, In the longitudinal section of the annular protrusion, in at least the upper half of the vertical direction, the length of the annular protrusion in the direction perpendicular to the vertical direction is monotonically or gradually decreasing as it moves downward from the upper surface of the annular protrusion, or monotonically or gradually increasing as it moves downward from the upper surface of the annular protrusion, and a substrate holding member is provided. The substrate is held in the substrate holding member, and the temperature distribution of the substrate is measured. Depending on the temperature distribution, the height of the annular protrusion from the upper surface of the ceramic substrate in the vertical direction is reduced across the entire upper surface of the annular protrusion. In accordance with the temperature distribution, the vertical height of all of the multiple protrusions from the upper surface of the ceramic substrate is reduced. A method for manufacturing a substrate holding member comprising the above.

6. A ceramic substrate having an upper surface and a lower surface that is opposite to the upper surface in the vertical direction, A substrate holding member comprising an electrode embedded in the ceramic substrate or disposed on the lower surface of the ceramic substrate, The aforementioned ceramic substrate is An annular protrusion is arranged on the outer periphery of the ceramic substrate and protrudes above the upper surface of the ceramic substrate, The ceramic substrate comprises a plurality of protrusions arranged inside the annular protrusion and projecting upward above the upper surface of the ceramic substrate, When the cross-section of the annular protrusion is defined as the vertical plane passing through the center of the ceramic substrate and parallel to the vertical direction, In the longitudinal section, within the upper half of the annular protrusion in the vertical direction, the length of the annular protrusion in the direction perpendicular to the vertical direction increases as it moves downward from the upper surface of the annular protrusion, In the longitudinal section, within the range of at least the lower half of the annular protrusion in the vertical direction, the length of the annular protrusion in the direction perpendicular to the vertical direction increases as it moves downward from the upper surface of the annular protrusion. A substrate holding member characterized in that the cross-sectional shape of the vertical plane passing through the center of the ceramic substrate on the inner circumferential surface of the annular protrusion is a downwardly convex quadratic curve.

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