Wafer mounting stage

Abstract

This wafer placement table 10 includes: a ceramic plate 20 having a wafer placement surface 22 on an upper surface; a cooling plate 30 provided on a lower surface of the ceramic plate 20; a coolant flow passage 32 provided in the cooling plate 30; and a heat insulating hole 40 provided on a side of the coolant flow passage 32 in the cooling plate 30 and reaching a ceiling 47 from a lower surface 38 of the cooling plate 30, the ceiling 47 being positioned higher than 2 / 3 the height of the coolant flow passage 32 from the bottom thereof.

Description

Technical Field

[0001] The present invention relates to a wafer mounting table.

Background Art

[0002] Conventionally, a wafer mounting table including a ceramic plate having a wafer mounting surface on its upper surface, a cooling plate provided on the lower surface of the ceramic plate, and a refrigerant flow path provided inside the cooling plate has been known. For example, in Patent Document 1, in such a wafer mounting table, a first heat insulating layer provided below the refrigerant flow path and a second heat insulating layer connected to the first heat insulating layer and provided on both sides of the refrigerant flow path up to a position of 1 / 3 to 2 / 3 of the height of the refrigerant flow path are provided. What has a cooling plate is disclosed. In Patent Document 1, by covering the refrigerant flow path with the first heat insulating layer and the second heat insulating layer to insulate heat from the lower surface of the cooling plate, it is possible to suppress the refrigerant from absorbing heat from the lower surface side of the cooling plate, and the cooling effect of the ceramic plate is improved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a wafer mounting table, it may be required to make the wafer mounting surface have a predetermined temperature distribution. For example, in a wafer mounting table provided with an electrostatic chuck for electrostatically adsorbing a wafer, making the wafer mounting surface have a uniform heat distribution may be a performance factor more important than improving the cooling effect. However, in Patent Document 1, although the cooling effect can be improved, the adjustment of the temperature distribution of the wafer mounting surface has not been studied.

[0005] This invention was made to solve these problems, and its main objective is to optimize the temperature distribution of the wafer mounting surface. [Means for solving the problem]

[0006] [1] The wafer mounting stage of the present invention is A ceramic plate having a wafer mounting surface on its upper surface, A cooling plate provided on the lower surface of the ceramic plate, A refrigerant flow path provided in the cooling plate, The cooling plate is provided on the side of the refrigerant flow path, and has an insulating hole extending from the lower surface of the cooling plate to the ceiling at a height higher than 2 / 3 of the height of the refrigerant flow path, It is something that is provided.

[0007] This wafer mounting platform has insulating holes on the sides of the refrigerant flow path, and these insulating holes extend from the lower surface of the cooling plate to the ceiling, which is higher than two-thirds of the way up from the bottom of the refrigerant flow path. In a wafer mounting platform comprising a ceramic plate with a wafer mounting surface on its upper surface, a cooling plate provided on the lower surface of the ceramic plate, and a refrigerant flow path provided in the cooling plate, when heat is input from the wafer mounting surface side, the refrigerant in the refrigerant flow path dissipates heat not only from the ceiling of the refrigerant flow path but also from the sides of the refrigerant flow path. The heat flux in the cooling plate at that time, depending on the material of the cooling plate, tends to be relatively large in the part on the sides of the refrigerant flow path that is higher than two-thirds of the way up from the bottom of the refrigerant flow path. By providing insulating holes in such a part with a large heat flux, they function as an insulating layer, and heat dissipation in the surrounding area is efficiently suppressed. Therefore, for example, by providing the above-mentioned insulating holes to correspond to the part of the wafer mounting surface where the temperature is lower than the desired temperature when there are no insulating holes, heat dissipation in that part can be suppressed, and the temperature distribution of the wafer mounting surface can be brought closer to the desired temperature distribution.

[0008] [2] In the wafer mounting stand of the present invention (the wafer mounting stand described in [1] above), the length between the ceiling of the heat insulating hole and the upper surface of the cooling plate may be 1 mm or more. If this length is 1 mm or more, damage to the wafer mounting stand is less likely to occur.

[0009] [3] In the wafer mounting stand of the present invention (the wafer mounting stand described in [1] or [2] above), the heat insulating holes may be provided between the flow paths of the refrigerant flow path. The cooling plate may have one refrigerant flow path or two or more, and the heat insulating holes may be provided between different parts of one flow path or between two or more different flow paths.

[0010] [4] In the wafer mounting stand of the present invention (the wafer mounting stand described in any of [1] to [3] above), the ceiling of the heat insulating hole may have a step or a slope. By providing a step or slope in the ceiling and raising the ceiling in the part where heat dissipation is to be suppressed more, the temperature distribution of the wafer mounting surface can be brought closer to the desired temperature distribution.

[0011] [5] In the wafer mounting stand of the present invention (the wafer mounting stand described in any of [1] to [4] above), the thermal conductivity of the cooling plate may be 100 W / (m·K) or higher. The higher the thermal conductivity of the cooling plate, the greater the effect of suppressing heat dissipation by the insulating holes. This is because, when heat is input from the wafer mounting surface side, the heat flux in the portion above 2 / 3 of the height of the refrigerant flow path on the side of the refrigerant flow path (the portion where the insulating holes are provided) tends to be relatively larger than the heat flux in the other portions.

[0012] [6] In the wafer mounting stand of the present invention (the wafer mounting stand described in any of [1] to [5] above), the heat insulating holes may be provided so as to correspond to a portion of the wafer mounting surface where the temperature is locally low when the heat insulating holes are absent. This suppresses heat dissipation from the portion of the wafer mounting surface where the temperature is locally low, thereby improving the uniformity of the heat on the wafer mounting surface. Note that the "portion of the wafer mounting surface where the temperature is locally low when the heat insulating holes are absent" may be confirmed by actually using the wafer mounting stand before the heat insulating holes are provided, or by using a wafer mounting stand with heat insulating holes provided, in which the heat insulating holes are filled with the same material as the cooling plate. [Brief explanation of the drawing]

[0013] [Figure 1] A longitudinal cross-sectional view of the wafer mounting stage 10. [Figure 2] Plan view of wafer mounting platform 10. [Figure 3] Cross-sectional view AA in Figure 1. [Figure 4] A magnified view of a portion of Figure 1, including the insulation hole 40. [Figure 5] Figure 2 shows a magnified view of the BB cross section including the insulation holes 40. [Figure 6] Manufacturing process diagram for wafer mounting platform 10. [Figure 7] A magnified view of a portion corresponding to Figure 4, showing another example of the insulation holes 40. [Figure 8] A magnified view of a portion corresponding to Figure 4, showing another example of the insulation holes 40. [Figure 9] A magnified view of a portion corresponding to Figure 5, showing another example of the insulation holes 40. [Figure 10] A magnified view of a portion corresponding to Figure 5, showing another example of the insulation holes 40. [Figure 11] A magnified view of a portion corresponding to Figure 4, showing another example of the insulation holes 40. [Figure 12] A magnified view of a portion corresponding to Figure 4, showing another example of the insulation holes 40. [Figure 13] An explanatory diagram showing an example of heat flux distribution in the longitudinal section of a cooling plate.

Best Mode for Carrying Out the Invention

[0014] Next, a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of the wafer stage 10 (a sectional view when the wafer stage 10 is cut along a plane including the central axis of the wafer stage 10). FIG. 2 is a plan view of the wafer stage 10. FIG. 3 is a sectional view taken along line A-A of FIG. 1. FIG. 4 is a partially enlarged view including the heat insulation hole 40 of FIG. 1. FIG. 5 is a partially enlarged view including the heat insulation hole 40 in the B-B section of FIG. 2.

[0015] The wafer stage 10 is used for performing CVD, etching, etc. on the wafer W using plasma. The wafer stage 10 includes a ceramic plate 20, a cooling plate 30, and a bonding layer 50.

[0016] The ceramic plate 20 is formed of a ceramic material typified by alumina, aluminum nitride, etc. The ceramic plate 20 has a wafer mounting surface 22, an electrostatic electrode 23, and a focus ring mounting surface 24. Hereinafter, the focus ring may be abbreviated as "FR".

[0017] The wafer mounting surface 22 is a circular surface provided on the upper surface of the ceramic plate 20. The wafer W is mounted on the wafer mounting surface 22. Although not shown, an annular seal band is formed along the outer edge on the wafer mounting surface 22, and a plurality of circular small protrusions are formed on the entire surface of the region surrounded by the seal band. The seal band and the circular small protrusions have the same height, and the height is, for example, several μm to several tens of μm.

[0018] The electrostatic electrode 23 is a planar mesh electrode or plate electrode and is connected to a DC power supply (not shown) via a power supply terminal 52. When a DC voltage is applied to the electrostatic electrode 23 from the DC power supply, the wafer W is attracted and fixed to the wafer mounting surface 22 (specifically the upper surface of the seal band and the upper surface of the small circular protrusions) by electrostatic attraction force, and when the application of the DC voltage is removed, the attraction and fixation of the wafer W to the wafer mounting surface 22 is released. The power supply terminal 52 is provided so as to pass through an insulating tube 56 located in a through-hole of the terminal hole 54 that penetrates the cooling plate 30 and the bonding layer 50 in the vertical direction, from the lower surface 28 of the ceramic plate 20 to the lower surface of the electrostatic electrode 23.

[0019] The FR mounting surface 24 is provided in an annular shape around the wafer mounting surface 22. The height of the FR mounting surface 24 is one step lower than the height of the wafer mounting surface 22. An annular focus ring 60 is placed on the FR mounting surface 24. The focus ring 60 is made of, for example, Si. A circumferential groove 62 is provided above the inner surface of the focus ring 60 so as not to come into contact with the wafer W.

[0020] The cooling plate 30 is made of a metal material or a composite material of metal and ceramic. Examples of metal materials include Al, Ti, Mo, or alloys thereof. Examples of composite materials of metal and ceramic include metal matrix composites (MMC) and ceramic matrix composites (CMC). Specific examples of such composite materials include materials containing Si, SiC, and Ti (also called SiSiCTi), materials in which Al and / or Si are impregnated into a porous SiC body, and composite materials of Al2O3 and TiC. The cooling plate 30 is equipped with a refrigerant channel 32 through which a refrigerant can circulate. As shown in Figure 2, the refrigerant channel 32 is provided so as to extend across the entire surface of the ceramic plate 20 in a single continuous line from one end (inlet 32in) to the other end (outlet 32out) in a plan view. In this embodiment, the refrigerant channel 32 is formed in a spiral shape in a plan view. Such a cooling plate 30 can be manufactured, for example, by diffusion bonding multiple layered members. The refrigerant is supplied from a refrigerant circulation device (not shown) to the inlet 32in of the refrigerant flow path 32, passes through the refrigerant flow path 32, and is discharged from the outlet 32out of the refrigerant flow path 32 and returned to the refrigerant circulation device. The refrigerant circulation device can adjust the refrigerant to a desired temperature. The refrigerant is preferably a liquid and preferably electrically insulating. Examples of electrically insulating liquids include fluorine-based inert liquids. The cooling plate 30 is provided with insulating holes 40 on the side of the refrigerant flow path 32. The insulating holes 40 are provided from the lower surface 38 of the cooling plate 30 to the ceiling 47 which is higher than two-thirds of the height of the refrigerant flow path 32. The insulating holes 40 are hollow and their interior may be filled with air or a gas such as He, or it may be a vacuum.

[0021] The bonding layer 50 joins the lower surface 28 of the ceramic plate 20 to the upper surface 36 of the cooling plate 30. The bonding layer 50 may be, for example, a metal layer formed from solder or metal brazing material, or a resin layer formed from a resin adhesive.

[0022] The insulation holes 40 will be explained using Figures 3 to 5. As shown in Figure 3, the insulation holes 40 are provided in a groove-like shape along the flow paths of the refrigerant flow path 32, with a gap between them. Also, as shown in Figures 4 and 5, the insulation holes 40 open to the lower surface 38 of the cooling plate 30 and have a shape that is carved straight from the opening to the ceiling 47. The ceiling 47 of the insulation holes 40 is provided at a height of 2h / 3 from the bottom 34 of the refrigerant flow path 32 (a virtual plane S shown by a dashed line), where h is the height of the refrigerant flow path 32. In this embodiment, the ceiling 47 of the insulation holes 40 is flat and is provided on a plane at the same height as the ceiling 33 of the refrigerant flow path 32 (a virtual plane T shown by a dashed line). The length a between the ceiling 47 of the insulation holes 40 and the upper surface 36 of the cooling plate 30 is, for example, 1 mm or more and 15 mm or less. This length a may be the same as or different from the length i between the ceiling 33 of the refrigerant flow path 32 and the upper surface 36 of the cooling plate 30. The length i between the ceiling 33 of the refrigerant flow path 32 and the upper surface 36 of the cooling plate 30 is, for example, 2 mm or more and 5 mm or less. The width b of the insulation hole 40 should be set appropriately so that the wall thickness d between the insulation hole 40 and the refrigerant flow path 32 is greater than or equal to a predetermined value (for example, 2 mm or more), but for example, it is between 2 mm and 16 mm. The spacing j between the flow paths of the refrigerant flow path 32 is, for example, between 6 mm and 20 mm. The length c of the insulation hole 40 is, for example, between 5 mm and 300 mm. below The length c of the insulation hole 40 may be the length in the direction along the direction of travel of the refrigerant flow path 32 (longitudinal direction), and the width b of the insulation hole 40 may be the length in the direction perpendicular to the longitudinal and height directions. The heat removal performance can be adjusted by adjusting the length a, width b, length c, etc. of the insulation hole 40 as described above, thereby adjusting the volume.

[0023] Next, an example of using the wafer mounting stand 10 will be described. The wafer mounting stand 10 is fixed inside a semiconductor process chamber (not shown). A focus ring 60 is placed on the FR mounting surface 24, and a wafer W is placed on the wafer mounting surface 22. In this state, a DC voltage is applied to the electrostatic electrode 23 to attract the wafer W to the wafer mounting surface 22. At the same time, a heat conductive gas (such as He gas) is supplied to a gas passage (not shown) provided inside the wafer mounting stand 10 (a passage from the lower surface 38 of the cooling plate 30 to the wafer mounting surface 22). As a result, the space enclosed by the lower surface of the wafer W and the sealing band of the wafer mounting surface 22 is filled with gas, improving heat conduction between the wafer W and the wafer mounting surface 22. Then, the inside of the chamber is set to a predetermined vacuum atmosphere (or reduced pressure atmosphere), and an RF voltage is applied to the cooling plate 30 while supplying process gas from a shower head provided on the ceiling of the chamber. Plasma is then generated between the wafer W and the shower head. Then, that plasma is used to perform CVD film deposition or etching on the wafer W.

[0024] When a wafer W is processed with plasma in this manner, the wafer W becomes hot due to the heat input from the plasma. A coolant flows through the coolant channel 32 of the wafer mounting table 10, and heat is removed from the wafer W via the ceramic plate 20, bonding layer 50, and cooling plate 30. It is desirable that the heat is removed in such a way that the wafer W reaches a desired temperature distribution. Here, when heat is input from the wafer mounting surface 22 side of the wafer mounting table 10, the coolant in the coolant channel 32 removes heat not only from the ceiling 33 of the coolant channel 32 but also from the side 35 of the coolant channel 32. The heat flux in the cooling plate 30 at that time, depending on the material of the cooling plate 30, tends to be relatively large in the part above the bottom two-thirds of the height of the coolant channel 32 on the side of the coolant channel 32. This point will be explained using Figure 13. Figure 13 is an explanatory diagram showing an example of the heat flux distribution in the vertical cross-section of a cooling plate (without insulating holes). Figure 13 is a contour map showing an example of heat flux within a cooling plate, specifically when the cooling plate material is Al, the wafer mounting surface is 80°C, and a -10°C refrigerant is flowing through it. From Figure 13, it can be seen that the heat flux within the cooling plate tends to be relatively large in the portion above the bottom two-thirds of the height of the refrigerant flow path, on the side of the refrigerant flow path. By providing insulating holes 40 in this portion with a large heat flux, they function as an insulating layer, and heat dissipation in the surrounding area is efficiently suppressed. Therefore, for example, by providing insulating holes 40 to correspond to the portion of the wafer mounting surface 22 where the temperature is lower than the desired temperature when insulating holes 40 are absent, heat dissipation in that portion can be suppressed, and the temperature distribution of the wafer mounting surface 22 can be brought closer to the desired temperature distribution.

[0025] Next, an example of the manufacturing of the wafer mounting stand 10 will be explained using Figure 6. First, a wafer mounting stand 10A before adjustment is prepared, which includes a ceramic plate 20, a cooling plate 30A before adjustment, and a bonding layer 50 (Figure 6A). In the wafer mounting stand 10A before adjustment, the ceramic plate 20 and bonding layer 50 are the same as the ceramic plate 20 and bonding layer 50 of the wafer mounting stand 10 described above, and the cooling plate 30A before adjustment is the same as the cooling plate 30 except that it does not have heat insulating holes 40. Next, an adjustment process is performed on the wafer mounting stand 10A before adjustment in which heat insulating holes 40 are carved from the lower surface of the cooling plate 30A before adjustment up to the ceiling 47, which is higher than 2 / 3 of the height below the refrigerant flow path 32 (Figure 6B). In this way, heat dissipation can be easily suppressed by carving heat insulating holes 40 from the lower surface 38 of the cooling plate 30A before adjustment on the wafer mounting stand 10A before adjustment.

[0026] Before the adjustment process, a measurement process is performed to measure the temperature distribution of the wafer mounting surface 22 of the wafer mounting stand 10A before adjustment. In the adjustment process, based on the temperature distribution measured in the measurement process, insulating holes 40 may be carved to correspond to the parts of the wafer mounting surface 22 where the temperature is lower than the desired temperature. In this way, the arrangement and shape of the insulating holes 40 can be adjusted according to the measured temperature distribution, making it easy to adjust the amount of heat dissipation with high accuracy.

[0027] In the wafer mounting platform 10 described above, the cooling plate 30 is provided with insulating holes 40 on the side of the refrigerant flow path 32. The insulating holes 40 extend from the lower surface 38 of the cooling plate 30 to the ceiling 47, which is higher than two-thirds of the height of the refrigerant flow path. Therefore, even if there is a part of the wafer mounting surface 22 whose temperature is lower than the desired temperature when the insulating holes 40 are absent, by providing the insulating holes 40 corresponding to that part, heat dissipation from that part can be suppressed, and the temperature distribution of the wafer mounting surface 22 can be brought closer to the desired temperature distribution.

[0028] Furthermore, it is preferable that the length a between the upper surface 36 of the cooling plate 30 and the ceiling 47 of the heat-insulating hole 40 be 1 mm or more. If this length is 1 mm or more, damage to the wafer mounting stand 10 is less likely to occur.

[0029] Furthermore, it is preferable that the thermal conductivity of the cooling plate 30 is 100 W / (m·K) or higher. The higher the thermal conductivity of the cooling plate 30, the greater the heat flux tends to be relatively larger in the portion of the refrigerant flow path 32 that is higher than the bottom two-thirds of the height of the refrigerant flow path 32 (the portion where the insulating holes 40 are provided) compared to the heat flux in other portions, thus increasing the effectiveness of heat dissipation suppression by the insulating holes 40. Note that Al and Al alloys have a thermal conductivity of 150 to 200 W / (m·K) and are preferred materials for the cooling plate 30. When the cooling plate 30 is Al or an Al alloy, the bonding layer 50 is often a resin layer.

[0030] Furthermore, it is preferable that the heat insulating holes 40 are provided so as to correspond to areas of the wafer mounting surface 22 where the temperature is locally low if the heat insulating holes 40 are not present. This suppresses heat dissipation from areas of the wafer mounting surface 22 where the temperature is locally low, thereby improving the uniformity of the heat on the wafer mounting surface 22. Examples of areas of the wafer mounting surface 22 where the temperature is locally low if the heat insulating holes 40 are not present include the area around the inlet 32in of the refrigerant flow path 32, and areas where the spacing between flow paths of the refrigerant flow path 32 is narrowed due to the arrangement of terminal holes 54, etc.

[0031] It goes without saying that the present invention is not limited in any way to the embodiments described above, and can be implemented in various forms as long as they fall within the technical scope of the present invention.

[0032] For example, in the embodiment described above, the ceiling 47 of the heat-insulating hole 40 is flat, but the ceiling 47 does not have to be flat. For example, as shown in Figure 7, it may have a step 47s in the width direction, or as shown in Figure 8, it may have a slope 47t in the width direction. Also, for example, as shown in Figure 9, it may have a step 47s in the length direction, or as shown in Figure 10, it may have a slope 47t in the length direction. Even if a heat-insulating hole 40 with a flat ceiling 47 is provided, there may be parts where heat dissipation is not sufficiently suppressed, or there may be parts where it is desired to suppress heat dissipation and make them slightly hotter. By raising the position of the ceiling 47 in those parts (parts where heat dissipation is to be suppressed more) higher than in other parts, the temperature distribution of the wafer mounting surface 22 can be brought closer to the desired temperature distribution.

[0033] In the embodiment described above, one insulation hole 40 is provided in the space between the refrigerant flow paths 32 (see space j in Figure 4), but multiple insulation holes may be provided, and the height of the ceilings of each hole may be the same or different. For example, as shown in Figures 11 and 12, two insulation holes 40, insulation hole 40a and insulation hole 40b, may be provided in the space between the refrigerant flow paths 32. Also, the height of the ceiling 47a of insulation hole 40a and the height of the ceiling 47b of insulation hole 40b may be the same as in Figure 11, or different as in Figure 12. By providing multiple insulation holes 40 in the space between the refrigerant flow paths 32, heat dissipation around the holes can be suppressed while avoiding through holes and the like provided in the cooling plate 30. Furthermore, by setting the ceiling heights of multiple insulation holes 40 to be different, even if multiple insulation holes 40 with the same ceiling height are provided, there may be areas where heat dissipation is not sufficiently suppressed, or areas where it is desirable to suppress heat dissipation and raise the temperature slightly. In such cases, by raising the ceiling 47 (ceiling 47b in Figure 12) of those areas (areas where heat dissipation is to be suppressed more), the temperature distribution of the wafer mounting surface 22 can be brought closer to the desired temperature distribution.

[0034] In the embodiment described above, the heat insulating hole 40 is assumed to be a single hole along the length of the refrigerant flow path 32, but two or more holes may be provided.

[0035] In the embodiment described above, the heat insulating holes 40 are provided between the flow paths of the refrigerant flow path 32. However, the heat insulating holes may be provided on the side of the refrigerant flow path 32, for example, on the outermost side of the flow path.

[0036] In the embodiment described above, it is assumed that there is one refrigerant flow path 32, but there may be two or more. In that case, the heat insulating holes 40 may be provided between different parts of one refrigerant flow path 32, or between two or more different refrigerant flow paths 32.

[0037] In the embodiment described above, the heat insulating holes 40 are provided in a groove shape along the refrigerant flow path 32, but they may also be provided in the shape of holes with approximately the same width and length. Furthermore, although the heat insulating holes 40 are provided in a curved shape along the refrigerant flow path 32, they may also be provided in a straight shape.

[0038] In the embodiment described above, the insulation holes 40 are hollow, but the insulation holes 40 may be filled with insulation material. However, it is preferable not to fill them with insulation material, as this allows for easier suppression of heat loss, as the insulation layer can be added simply by machining to form the insulation holes.

[0039] In the embodiment described above, an electrostatic electrode 23 is incorporated inside the ceramic plate 20 at a position facing the wafer mounting surface 22. In addition, an FR adsorption electrode for electrostatically adsorbing the focus ring 60 may be provided inside the ceramic plate 20 at a position facing the FR mounting surface 24.

[0040] In the embodiments described above, the ceramic plate 20 is exemplified as having a wafer mounting surface 22 and an FR mounting surface 24, but it is not particularly limited thereto. For example, the ceramic plate 20 may have a wafer mounting surface 22 but not an FR mounting surface 24.

[0041] In the embodiment described above, the refrigerant flow path 32 was formed in a spiral shape in a plan view, but the embodiment is not limited to this. For example, the refrigerant flow path 32 may be formed in a zigzag shape in a plan view.

[0042] In the embodiments described above, a wafer mounting stage 10 with an electrostatic electrode 23 built into a ceramic plate 20 was illustrated, but the invention is not limited thereto. For example, instead of or in addition to the electrostatic electrode 23, a heater electrode (resistive heating element) or a plasma generating electrode (RF electrode) may be built into the ceramic plate 20.

[0043] In the embodiment described above, the wafer mounting base 10 may have a plurality of lift pin holes that penetrate vertically through the wafer mounting base 10. The lift pin holes are holes for inserting lift pins to move the wafer W up and down relative to the wafer mounting surface 22. For example, a plurality of lift pin holes are provided at equal intervals along the concentric circles of the wafer mounting surface 22 when the wafer mounting surface 22 is viewed from above. [Examples]

[0044] Examples of the present invention will be described below. Note that the following examples do not limit the present invention in any way.

[0045] [Example 1] The temperature distribution of the wafer mounting surface 22 was investigated by simulating a case where heat was input from the wafer mounting surface 22 side for wafer mounting stands 10A and 10 before and after adjustment. Specifically, an external heater was heated so that the steady temperature on the wafer mounting surface 22 side was approximately 80°C, and the temperature distribution of the wafer mounting surface 22 was investigated when a refrigerant at -10°C was circulated in the refrigerant flow path 32. The cooling plates 30A and 30 before and after adjustment were both made of aluminum. In addition, in the wafer mounting stand 10 after adjustment, the ceiling 47 of the insulation hole 40 was at the same height as the ceiling 33 of the refrigerant flow path 32, the width b of the insulation hole 40 was 8 mm, the length c of the insulation hole 40 was 100 mm, and the wall thickness d between the insulation hole 40 and the refrigerant flow path 32 was 3 mm. The temperature distribution of the wafer mounting surface 22 on wafer mounting stands 10A and 10 before and after adjustment was then compared. In the adjusted wafer mounting table 10, the temperature of the portion of the wafer mounting surface 22 above the heat insulating holes 40 was about 1.5°C higher compared to the wafer mounting table 10A before adjustment. This indicates that providing the heat insulating holes 40 can suppress heat dissipation in that area. From this, it was found that by providing the heat insulating holes 40 to correspond to the portion of the wafer mounting surface 22 where the temperature is lower than the desired temperature when the heat insulating holes 40 are absent, heat dissipation in that portion can be suppressed, and the temperature distribution of the wafer mounting surface 22 can be brought closer to the desired temperature distribution. [Industrial applicability]

[0046] This invention is applicable to semiconductor manufacturing equipment. [Explanation of Symbols]

[0047] 10 Wafer mounting stage, 10A Wafer mounting stage before adjustment, 20 Ceramic plate, 22 Wafer mounting surface, 23 Electrostatic electrode, 24 Focus ring mounting surface, 28 Bottom surface, 30 Cooling plate, 30A Cooling plate before adjustment, 32 Coolant flow path, 32in Inlet, 32out Outlet, 33 Top, 34 Bottom, 35 Side, 36 Top surface, 38 Bottom surface, 40, 40a, 40b Insulation holes, 47, 47a, 47b Top, 50 Bonding layer, 52 Power supply terminal, 54 Terminal hole, 56 Insulating tube, 60 Focus ring, 62 Circumferential groove, W Wafer.

Claims

1. A ceramic plate having a wafer mounting surface on its upper surface, A cooling plate provided on the lower surface of the ceramic plate, A refrigerant flow path provided in the cooling plate, The cooling plate is provided on the side of the refrigerant flow path, and has an insulating hole extending from the lower surface of the cooling plate to the ceiling at a height higher than two-thirds of the way up from the bottom of the refrigerant flow path, Equipped with, The ceiling of the aforementioned insulation hole has a step or slope. Wafer mounting stand.

2. A ceramic plate having a wafer mounting surface on its upper surface, A cooling plate provided on the lower surface of the ceramic plate, A refrigerant flow path provided in the cooling plate, The cooling plate is provided on the side of the refrigerant flow path, and has an insulating hole extending from the lower surface of the cooling plate to the ceiling at a height higher than two-thirds of the way up from the bottom of the refrigerant flow path, Equipped with, The aforementioned heat-insulating holes are provided so as to correspond to the portion of the wafer mounting surface where the temperature would be locally low if the heat-insulating holes were absent. Wafer mounting stand.

Images