JP2007035878A - Wafer retainer and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wafer retainer capable of uniformizing a temperatures in the surface of a wafer even if the wafer is abruptly heated by plasma or the like, and to provide its manufacturing method. <P>SOLUTION: The wafer retainer 1 is constituted of a plate-type ceramic body 2 whose upper surface is used as a wafer mounting surface 3, and which is arranged on a base member 4 for cooling the plate-type ceramic body 2 from the lower surface side thereof through an interposing layer 6 having a region 6b different in heat conductivity from that of the interposing layer 6. The region 6b having different heat conductivity is provided in the interposing layer 6, and therefore, heat transfer between the plate-type ceramic body 2 and the base member 4 is changed, whereby the temperatures in the surface of the wafer can be uniform. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wafer holder that holds a wafer such as a semiconductor wafer such as a silicon substrate or a liquid crystal substrate, and more particularly to a wafer holder that has a function of heating while holding a semiconductor wafer, or a function of electrostatically adsorbing a wafer. The present invention relates to an electrostatic chuck with a heater.

  Conventionally, in the semiconductor manufacturing process, the wafer is accurately held in the exposure process on the semiconductor wafer, the film formation process by PVD, CVD, sputtering, etc., the etching process by plasma etching or photoetching, or the dicing process. For this purpose, a wafer holder is used.

  In many cases, the wafer holder is used under reduced pressure. In the film formation process, the wafer is heated by a reaction gas during film formation. In the etching process, plasma etching gas, ultraviolet light or visible light during photoexcited etching is used. Therefore, it is necessary to efficiently release the heat applied to the wafer by the wafer holder so that the surface temperature of the wafer does not increase.

  Therefore, in order to efficiently release the heat of the wafer, it has been proposed to use a wafer holder provided with a base member having a cooling function.

  For example, in the wafer holder 100 shown in a cross-sectional view in FIG. 14, one main surface of the disk-shaped plate-shaped ceramic body 2 is a wafer mounting surface 3 on which a wafer is placed, and the wafer-shaped ceramic body 2 is statically placed in the plate-shaped ceramic body 2. A base member 4 is bonded to the side opposite to the wafer mounting surface 3 of the electrostatic chuck portion in which the electrode 9 for electroadsorption is embedded via an intervening layer 60. The base member 4 is cooled by flowing cooling water so that heat applied to a wafer (not shown) sucked and held on the wafer mounting surface 3 is released.

  Further, as shown in a cross-sectional view in FIG. 15, in the wafer holder 100 disclosed in Patent Document 1, one main surface of the disk-shaped plate-shaped ceramic body 2 is a wafer mounting surface 3 on which a wafer is placed. The electrostatic chuck portion having the electrostatic chucking electrode 9 on the other main surface, and the base member 4 are bonded to the opposite side of the wafer mounting surface 3 of the electrostatic chuck portion via the intervening layer 60. Yes. The base member 4 is cooled by flowing cooling gas or cooling water through the cooling passage 5 formed in the base member 4 so as to release heat applied to the wafer (not shown) adsorbed and held on the wafer holder 100. It has become.

  By the way, in order to form a homogeneous film on the entire surface of the wafer or to make the reaction hardening state uniform by heating the resist film, it is required to make the temperature of the wafer surface uniform.

On the other hand, since the wafer and the wafer placement surface 3 are in direct contact with each other or close to each other, the temperature distribution in the wafer surface has a high correlation with the in-plane temperature of the wafer placement surface 3. From this point, it is important that the surface temperature of the wafer mounting surface 3 of the wafer holder is uniform.
JP 2003-224180 A

  However, the conventional wafer holder 100 described in Patent Document 1 can quickly release heat to the base member 4 when the wafer is rapidly heated by plasma or the like. The temperature difference of the surface of the mounting surface 3 is large, and it is difficult to keep the temperature in the wafer surface constant and constant at a constant temperature (for example, 60 ° C.). And since the temperature in the surface of a wafer is not uniform, there existed a possibility that the semiconductor element of a part in a wafer might become defective, and the yield of a semiconductor element might fall.

  Moreover, since the conventional wafer holder 100 cannot adjust the temperature difference in the surface of the wafer mounting surface 3 small after the wafer holder 100 is assembled, the surface of the wafer mounting surface 3 of the wafer holder If the internal temperature difference is 3 ° C. or less, for example, the requirement becomes severe, the production yield of the wafer holder 100 may be significantly reduced.

  Further, in the method of heating the wafer by lamp heating or plasma heating, the temperature difference in the wafer surface may vary greatly depending on the set temperature. Further, when the temperature of the wafer is higher than 80 ° C., the temperature uniformity of the wafer mounting surface 3 is poor, and the temperature difference in the mounting surface may exceed 3 ° C.

  In addition, the temperature distribution of the wafer surface and the wafer mounting surface 3 cannot be confirmed unless the wafer holder 100 is incorporated in a semiconductor manufacturing apparatus and the wafer surface is actually heated by lamp heating or plasma heating. Therefore, it has been extremely difficult to reduce the temperature difference in the mounting surface of the wafer holder 100.

  The wafer holder of the present invention includes an intervening layer having regions having different thermal conductivities on the upper surface of a base member that cools the plate-shaped ceramic body from the lower surface side. It is characterized by having arranged.

  Further, the wafer holder of the present invention is characterized in that, in the above configuration, a plate-like heater member for heating the plate-like ceramic body from the lower surface side is disposed between the plate-like ceramic body and the base member. To do.

  The wafer holder of the present invention is characterized in that, in the above configuration, the intervening layer is disposed between the heater member and the base member.

  Moreover, the wafer holder of the present invention is characterized in that, in each of the above configurations, the intervening layer is made of an adhesive.

  Further, in the wafer holder of the present invention, in each of the above-described configurations, the region having a different thermal conductivity of the intervening layer is heated corresponding to a portion having a low temperature with respect to a temperature distribution during heating by the heater member. It is characterized by being arranged as a region with low conductivity.

  Further, the wafer holder of the present invention is characterized in that, in the above configuration, the intervening layer is disposed between the heater member and the base member, and a region having a low thermal conductivity is disposed in a peripheral portion. .

  The wafer holder of the present invention is characterized in that, in the above configuration, the region having a low thermal conductivity is a void.

  Further, in the wafer holder of the present invention, in each of the above-described configurations, the region having a different thermal conductivity of the intervening layer is heated corresponding to a portion having a high temperature with respect to a temperature distribution during heating by the heater member. It is characterized by being arranged as a region with high conductivity.

  The wafer holder of the present invention is characterized in that, in each of the above-described configurations, an adsorption electrode for adsorbing a wafer to the wafer mounting surface is provided on the lower surface or inside of the plate-like ceramic body.

  The method for manufacturing a wafer holder of the present invention includes a plate-shaped ceramic body having an upper surface as a wafer mounting surface, a base member that cools the plate-shaped ceramic body from the lower surface side, the plate-shaped ceramic body, and the base A step of preparing a plate-like heater member disposed between the member and heating the plate-like ceramic body from the lower surface side, a step of measuring the temperature distribution by heating the heater member, and the heater member A region having a low thermal conductivity is arranged corresponding to a portion having a low temperature relative to the temperature distribution of the temperature distribution, or an intervening layer having a region having a high thermal conductivity arranged corresponding to a portion having a high temperature The method includes the steps of disposing the heater member on the upper surface of the base member, and disposing the plate-like ceramic body on the upper surface of the heater member via an intervening layer.

  In the wafer holder of the present invention, one main surface (upper surface) of the plate-shaped ceramic body is used as a mounting surface on which the wafer is placed, and a cooling base member is provided on the other main surface (lower surface) side of the plate-shaped ceramic body. And providing an intervening layer having regions having different thermal conductivities between the plate-like ceramic body and the base member, thereby transferring heat at the interface formed by the intervening layer between the plate-like ceramic body and the base member. Since the thermal conductivity in the plane of the intervening layer can be adjusted by the difference in the direction, heat can be released to the outside from the base member through the cooling medium, and a partial surface of the wafer by plasma or the like can be emitted. It is possible to prevent overheating and an increase in temperature difference on the wafer surface. Furthermore, an intervening layer having regions with different thermal conductivities should increase or decrease the thermal conductivity of each part of the intervening layer at the interface between the plate-shaped ceramic body and the base member due to the difference in thermal conductivity. Since the amount of heat passing through each part of the intervening layer can be adjusted, a wafer holder having a small in-plane temperature difference of 3 ° C. or less in the low temperature region from room temperature to about 100 ° C. can be provided. And the yield of the semiconductor element cut out from the wafer manufactured using this wafer holder can be improved.

  Also, if an intervening layer is disposed between the heater member and the base member, the amount of heat passing through the intervening layer is large, so the difference in the way heat is transferred in the plane of the intervening layer due to the difference in thermal conductivity, Since the change in the amount of heat in the surface of the intervening layer can be increased, a larger temperature difference in the mounting surface can be reduced.

  In addition, when this intervening layer is made of an adhesive, there is no risk of unnecessary gaps between the intervening layer and the heater member or base member, and a wafer holder having a small in-plane temperature difference on the mounting surface as designed. It is easy to obtain.

  In addition, when a region having a low thermal conductivity is arranged corresponding to a portion where the temperature is low with respect to the temperature distribution during heating by the heater member, the flow of heat from this region to the base member is reduced, and Since the temperature drop of the opposing mounting surface can be prevented, the surface temperature difference between the wafer mounting surfaces is reduced.

  Further, in the wafer holder, the temperature of the peripheral part tends to decrease, but when a region having a low thermal conductivity is arranged between the heater member and the base member and the peripheral part, Since the amount of heat transferred to the base member is reduced and the temperature of the peripheral portion of the mounting surface can be increased, the in-plane temperature difference of the mounting surface can be reduced. Further, when the region having a small thermal conductivity in the peripheral portion is a gap, generally, the thermal conductivity of the void is very small, so that the amount of heat transferred from the periphery can be reduced more efficiently. .

  In addition, when a region having a high thermal conductivity is disposed in the intervening layer corresponding to a portion where the temperature is high with respect to the temperature distribution during heating by the heater member, the heater member is moved from the heater member to the base member in the region having a high thermal conductivity. Since heat easily escapes, the temperature of the heater member facing this region can be lowered, and the temperature difference in the mounting surface can be reduced correspondingly.

  Further, when an adsorption electrode is provided on the lower surface or inside of the plate-like ceramic body, an adsorption force acts between the wafer and the placement surface, so that the wafer can be satisfactorily adhered to the placement surface. Is easily transmitted to the wafer, and the temperature difference in the wafer surface is reduced.

  Further, according to the method for manufacturing a wafer holder of the present invention, a plate-shaped ceramic body having an upper surface as a wafer mounting surface, a base member for cooling the plate-shaped ceramic body from the lower surface side, and the plate-shaped ceramic body, A step of preparing a plate-like heater member disposed between the base member and heating the plate-like ceramic body from the lower surface side, a step of measuring the temperature distribution by heating the heater member, A region having a low thermal conductivity is arranged corresponding to a portion where the temperature is low with respect to the temperature distribution of the heater member, or an intervening layer where a region having a high thermal conductivity is arranged corresponding to a portion where the temperature is high. And a step of disposing the heater member on the upper surface of the base member and a step of disposing the plate-like ceramic body on the upper surface of the heater member via an intervening layer, thereby providing thermal conductivity with respect to temperature distribution. The small wafer holder plane temperature difference of the mounting surface from the adjustable so that small-plane temperature difference of the mounting surface by arranging the different regions can be produced stably.

  Hereinafter, an electrostatic chuck 10 having a function of electrostatically attracting a wafer will be described as an example of an embodiment of the wafer holder 1 of the present invention.

  FIG. 1A is a schematic perspective view showing an example of an embodiment of a wafer holder 1 of the present invention, and FIG. 1B is a schematic cross-sectional view taken along the line XX of FIG.

  The wafer holder 1 includes an intervening layer 6 between the plate-like ceramic body 2 and the base member 4. One main surface (upper surface) of the plate-like ceramic body 2 is a wafer mounting surface 3 on which a wafer is placed, and the other main surface (lower surface) side is for cooling the wafer mounting surface 3 via an intervening layer 6. The base member 4 is provided.

  In the wafer holder 1 of the present invention, the plate-like ceramic body 2 has a wafer mounting surface 3 on the upper surface, and the Young deformation is small so that a wafer (not shown) can be held on the wafer mounting surface 3 with high accuracy. It is comprised with the ceramic sintered compact whose rate is 200 GPa or more. Moreover, since it is easy to keep the temperature in the wafer mounting surface 3 uniform, it is preferable that it is made of a nitride ceramic or carbide ceramic having a thermal conductivity of 50 W / (m · K) or more.

  The wafer holder 1 is provided with a recess (not shown) on the wafer placement surface 3 and a gas supply port (not shown) communicating with the recess, and is formed by the lower surface of the wafer and the wafer placement surface 3. By filling the space with the gas from the gas supply port, the heat transfer efficiency from the wafer mounting surface 3 to the wafer can be increased.

  The base member 4 is made of a metal material such as aluminum or cemented carbide, or a composite material of the metal material and a ceramic material, and the base member 4 preferably has conductivity. The conductive base member 4 can also function as an electrode for generating plasma above the wafer mounting surface 3. In addition, a cooling passage 5 through which a cooling medium passes is provided inside the base member 4, and a cooling medium such as cooling gas or cooling water is allowed to flow through the cooling passage 5, thereby allowing the wafer placement surface 3 and the wafer placement surface 3 to flow. The temperature of the wafer placed on the substrate can be adjusted to a desired temperature.

  The intervening layer 6 is made of, for example, a resin adhesive such as silicone, polyimide or epoxy, a metal bonding member made of indium or the like, or a sheet-like resin or brazing material, and has a desired shape on a part of the surface of the intervening layer 6. A region 6b having a slightly different thermal conductivity is provided.

  Further, an adsorption electrode 9 for adsorbing the wafer is provided on the other main surface (lower surface) of the plate-like ceramic body 2. When a wafer is placed on the wafer placement surface 3 and a DC voltage is applied to the suction electrode 9, the wafer can be firmly attracted to the wafer placement surface 3 by electrostatic force. Moreover, a cooling medium can be flowed through the cooling passage 5 of the base member 4, and heat applied to the wafer can be discharged to the outside through the cooling medium. The adsorption electrode 9 may be embedded in the plate-like ceramic body 2.

  The wafer holder 1 of the present invention has a region having different thermal conductivity on the upper surface of a base member 4 that cools the plate-like ceramic body 2 from the lower surface side. By disposing via the intervening layer 6 having 6b, the temperature difference in the wafer placement surface 3 and the wafer surface can be reduced. The reason is that by providing the region 6b with different thermal conductivity in the intervening layer 6, the heat transfer from the region 6b to the upper surface of the base member 4 can be made different from the region 6a. This is because the flow of heat can be adjusted so that the temperature difference in the wafer surface and in the wafer mounting surface 3 is reduced even if the amount of heat applied to the wafer mounting surface 3 and the wafer surface facing each other is partially different. is there. For example, in a portion where a large amount of heat is applied to the surface of the wafer, the thermal conductivity of the intervening layer facing this portion is increased to facilitate the flow of heat to the base member 4, thereby preventing a partial temperature increase on the wafer surface. be able to. Then, by providing the intervening layer 6 with regions 6b having different thermal conductivities and making the thermal conductivities of the respective portions of the intervening layer 6 between the plate-like ceramic body 2 and the base member different, the wafer or the wafer mounting surface 3 The in-plane temperature difference can be reduced, preferably 3 ° C. or less.

  For example, when a wafer is placed on the wafer placement surface 3 of the wafer holder 1 for a semiconductor manufacturing apparatus and plasma is generated on the wafer placement surface 3, a specific portion within the wafer surface is caused by the difference in plasma density. May always be hot. Therefore, by arranging a region having a high thermal conductivity as a region 6b having a different thermal conductivity in the intervening layer 6 facing the high temperature portion of the wafer with the plate-like ceramic body 2 interposed therebetween, the temperature of the high temperature portion in the wafer surface is set. It is possible to reduce the temperature difference in the wafer surface.

  The thermal conductivity of the region 6b and the region 6a disposed in the intervening layer 6 can be obtained experimentally from the temperature difference in the surface of the wafer or the wafer mounting surface 3 or can be obtained by calculation. By disposing a region having a high thermal conductivity as the region 6b having a different thermal conductivity, heat is quickly transmitted from the wafer mounting surface 3 to the base member 4 through the region 6b, thereby causing an in-plane temperature difference of the wafer mounting surface 3. Therefore, the in-plane temperature difference of the wafer mounting surface 3 can be reduced to 3 ° C. or less, for example.

  Further, when a part of the wafer surface has a low temperature part and a region having a low temperature is generated in a part of the wafer mounting surface 3 facing the part, the part facing the low temperature part is opposed. By disposing a region having a low thermal conductivity as the region 6b having a different thermal conductivity in the intervening layer 6, the amount of heat escaping from the region 6b to the base member 4 can be suppressed, and the temperature of the portion of the wafer mounting surface 3 at a low temperature Therefore, the temperature difference within the wafer surface and the wafer mounting surface 3 can be reduced to, for example, 3 ° C. or less. Then, when various kinds of processing are performed on the wafer using such a wafer holder 1, there is no temperature difference between a plurality of elements formed in each part of the wafer surface, and uniform elements such as film quality and thickness between elements are eliminated. Therefore, the manufacturing yield of the semiconductor element manufactured on the wafer can be improved, which is preferable.

  Next, due to the influence of the shape of the cooling passage 5 provided in the base member 4, the wafer surface temperature may be partially lowered and the temperature difference in the wafer surface may be increased. Another example of the embodiment of the wafer holder 1 of the present invention in which the internal temperature difference is reduced will be described.

  FIG. 2 is a schematic top view showing a schematic shape of the cooling passage of the wafer holder of the present invention. FIG. 16 is a schematic sectional view of a conventional wafer holder 100. FIG. 17 is a schematic top view showing the temperature distribution on the wafer mounting surface 3 of the conventional wafer holder 100. When the plate-like ceramic body 2 is viewed from the wafer mounting surface 3 side, the base member 4 including the cooling passage 5 having a spiral shape as shown by a dotted line in FIG. 2 is fixed through a uniform intervening layer 60. The temperature distribution on the wafer mounting surface 3 of the conventional wafer holder 100 shown in FIG. 16 is as shown in FIG. That is, the temperature of the region 101 in FIG. 17 is as high as 60 to 61.5 ° C., the temperature of the region 102 is 58.5 to 60 ° C., and the temperature of the region 103 is 57 to 58.5 ° C. A region having a low temperature may occur opposite to the arrangement of the cooling passage 5.

  On the other hand, FIG. 3 is a schematic top view showing an example of the intervening layer 6 in the wafer holder 1 of the present invention. FIG. 4 is a schematic top view showing the temperature distribution of the wafer mounting surface 3 of the wafer holder 1 of the present invention provided with the intervening layer 6. As shown in FIG. 3, the intervening layer 6 in the present invention is arranged from the upper surface of the cooling passage 5 where the temperature of the base member 4 is low by disposing the region 6 b having low thermal conductivity opposite to the arrangement of the cooling passage 5. There is a possibility that a lot of heat is transmitted and the temperature of the wafer mounting surface 3 facing this region is lowered, but if there is a region having a small thermal conductivity facing this region, the amount of heat transfer is lowered and the temperature is low. The shape of the cooling passage 5 does not appear on the mounting surface, and the in-plane temperature difference of the wafer mounting surface can be reduced as shown in FIG. The temperature of the region 104 shown in FIG. 4 is 58.5 to 60 ° C., the temperature of the region 105 is 57 to 58.5 ° C., and the in-plane temperature difference of the wafer mounting surface 3 is reduced to within 3 ° C. Generation of a temperature difference in the wafer placement surface 3 due to the influence of the passage 5 can be prevented.

  Then, when trying to mass-produce the wafer holder 1 having an in-plane temperature difference of 3 ° C. or less on the wafer placement surface 3, the temperature difference in the wafer placement surface is not small when the conventional wafer holder is used. Although the manufacturing yield is about 40%, the temperature difference can be reduced in the wafer holder 1 of the present invention, so that the manufacturing yield is 70% or more and efficient mass production is possible.

  In the wafer holder 1 of the present invention, it is preferable that a plate-like heater member 8 for heating the plate-like ceramic body 2 from the lower surface side is disposed between the plate-like ceramic body 2 and the base member 4. A wafer holder 1 of the present invention in which a plate-like heater member 8 shown in a schematic cross-sectional view in FIG. 5 is arranged is a heat source for the heater member 8 to heat the wafer placement surface 3. A wafer (not shown) is heated through the gap. The inventor has found that when the wafer is heated by heating the heater member 8 while cooling the base member 4, the temperature distribution on the wafer surface shows the same tendency even if the heating setting temperature of the wafer changes. Further, when heat is supplied from the heater member 8 in a state where the heat is always discharged from the base member 4, even if the wafer is heated from above the wafer and heat is applied to the wafer mounting surface 3, It was found that the temperature was difficult to change. The reason is that the amount of heat A transmitted from the heater member 8 to the base member 4 is large, and the amount of heat B transmitted from above the wafer via the wafer to the wafer mounting surface 3 can be relatively small. I can guess it is small. Then, after measuring the temperature distribution of the single member of the heater member 8 in advance, the region 6b having different thermal conductivity is disposed in the intervening layer 6 so as to face the high temperature portion and the low temperature portion of the heater member 8, The in-plane temperature difference between the wafer surface and the wafer mounting surface 3 can be made smaller. And even if the variation in the amount of heat supplied from above the wafer surface is large, the temperature difference in the wafer surface can be reduced.

  As a specific example, as shown in a schematic top view in FIG. 6, the temperature of the surface of the heater member 8 is as high as 61.5 to 63 ° C. in the region 106, and the temperature in the region 108 is continuous with this. When the temperature is as low as 55.5 to 57 ° C., the thermal conductivity of the region 6a of the intervening layer 6 shown in the schematic top view in FIG. 7 is opposed to the region 106, with respect to 0.53 W / (m · K). A region 6b having a large thermal conductivity of 1.06 W / (m · K) and a region 6c having a small thermal conductivity of 0.27 W / (m · K) facing the region 108 are disposed as the intervening layer 6. And the temperature distribution of the wafer mounting surface 3 of the wafer holder 1 in which such an intervening layer 6 and the heater member 8 shown in FIG. 6 are arranged as shown in FIG. 5 is shown in a schematic top view in FIG. Furthermore, the temperature in the region 102a is 60 to 60.75 ° C., the region 102 is 58.5 to 60 ° C., the region 102b is 57.75 to 58.5 ° C., and the in-plane temperature difference of the wafer mounting surface 3 is 3 ° C. It became smaller and preferred.

  Further, when the wafer holder 1 having the heater member 8 is mass-produced, the manufacturing yield of the wafer holder 1 can be increased even if a small standard of 3 ° C. or less is set for the in-plane temperature difference of the wafer mounting surface 3. It was proved that the productivity was as high as 80% or more and showed excellent productivity.

  Moreover, it is preferable to arrange | position the intervening layer 6 which has the area | region where heat conductivity differs between the said heater member 8 and the said base member 4. FIG. FIG. 9 shows an example of the wafer holder 1 in which the heater member 8 is provided between the plate-like ceramic body 2 and the base member 4. In this wafer holder 1, an intervening layer 7 between the plate-like ceramic body 2 and the heater member 8 and an intervening layer 6 between the heater member 8 and the base member 4 are disposed. It is conceivable that the intervening layers 6 and 7 having regions 6b and 7b having different thermal conductivities are disposed in the intervening layer 6 and / or the intervening layer 7. However, the intervening surface on which the heat of the heater member 8 is forcibly released. It is preferable to arrange the region 6 b having different thermal conductivity in the layer 6. The reason is that the heat amount flowing through the intervening layer 6 is larger than the heat amount flowing through the intervening layer 7 even if the difference in thermal conductivity between the region 6b and the region 6a is small or the thermal conductivity of the region 6b is small. This is because even if the difference in thermal conductivity between the region 6b and the region 6a is small, the change in the amount of heat becomes large, so that a large temperature difference over a wide range of the wafer mounting surface 3 can be adjusted to be small. Further, the provision of the region 6a and the region 6b rather than the region 7a and the region 7b causes the intervening layer 6 to transmit more heat than the intervening layer 7, and thus the wafer placement surface 3 by the region 6b than the region 7b. Since the effect of changing the temperature inside is large, the action of the region 6b works effectively so that the larger temperature difference of the wafer mounting surface 3 becomes smaller due to the difference in thermal conductivity between the region 6b and the region 6a. It is preferable because the temperature difference of the wafer mounting surface 3 can be reduced.

  The heat generated by the heater member 8 heats the wafer placement surface 3 and adjusts the in-plane temperature of the wafer placement surface 3 while allowing the heat to flow out from the base member 4. The greater the temperature difference between the heater member 8 and the intervening layer 6 or 7, the greater the amount of heat flowing through the intervening layers 6, 7. Since the base member 8 is normally cooled, the temperature difference between the heater member 8 and the intervening layer 6 is larger than that between the heater member 8 and the intervening layer 7. Since the amount of heat flowing through the intervening layer 6 is larger than that of the intervening layer 7, if the region 6b having a different thermal conductivity is provided in the intervening layer 6 than the intervening layer 7, the change in the amount of heat is large. It is thought that the temperature change changes greatly. The temperature difference with the heater member 8 is larger in the intervening layer 6 than in the intervening layer 7. Therefore, the region 6 b having different thermal conductivity is disposed in the intervening layer 6 in the wafer mounting surface 3. This is preferable because a larger temperature difference can be adjusted to be smaller.

  In some cases, both the intervening layer 6 and the intervening layer 7 include the region 6b and the region 7b, but the arrangement of the regions 6b and 7b may be complicated and adjustment may be difficult as compared with the case where only the intervening layer 6 is provided. In addition, since the production cost of the wafer holder 1 increases, it is more preferable that the intervening layer 6 between the heater member 8 and the base member 4 has a region 6b having different thermal conductivity.

  The intervening layers 6 and 7 are preferably made of an adhesive. The reason is that, if the intervening layers 6 and 7 are made of an adhesive, the adhesiveness between the plate-shaped ceramic body 2, the heater member 8, and the base member 4 is good. Since there are no voids at the interface between the intervening layer 7 and the heater member 8, the interface between the heater member 8 and the intervening layer 6, and the interface between the intervening layer 6 and the base member 4, the thermal conductivity at these interfaces is low. This is because there is no possibility of partial variation. For example, compared with the wafer holder 1 in which the intervening layers 6 and 7 are made of sheet-like resin, the temperature difference in the wafer mounting surface 3 of the wafer holder 1 in which the intervening layers 6 and 7 are made of adhesive is smaller. It turned out to be preferable. When the intervening layer 6 is composed of a sheet-like resin, the intervening layer 6 sandwiched between the plate-like ceramic body 2 and the base member 4 is mechanically fixed with a bolt or the like. There may be a gap at the interface between the base member 4 and the intervening layer 6, and the thermal conductivity partially varies in the plane of the intervening layer 6, resulting in an in-plane temperature difference of the wafer mounting surface 3. It is because there is a possibility of becoming large.

  Moreover, it is preferable to arrange | position the area | region 6b with small heat conductivity corresponding to the part with low temperature with respect to the temperature distribution at the time of the heating by the heater member 8 in the area | region 6b from which the thermal conductivity of the intervening layer 6 differs. Heat passes from the upper surface of the base member 4 to the base member 4 through the region 6b facing the low temperature region of the heater member 8, and heat in the low temperature region is absorbed, but the temperature in the low temperature region is not lowered. By disposing the region 6b having a low thermal conductivity in the intervening layer 6b facing the low temperature region, it is possible to act to increase the temperature by suppressing the heat transfer in the low temperature region. Even if the heater member 8 is incorporated in the wafer holder 1, the low temperature region does not appear on the wafer placement surface 3, and the in-plane temperature difference of the wafer placement surface 3 can be reduced.

  Further, as shown in the schematic cross-sectional view of FIG. 11, the intervening layer 6 of the wafer holder 1 of the present invention is provided with a region 6c having a small thermal conductivity between the heater member 8 and the base member 4 and in the peripheral portion. It is preferable to arrange. When the region 6c having a low thermal conductivity is arranged around the intervening layer 6, the effect acts in a relatively narrow range compared to the central portion. In the case of the peripheral portion, the surrounded range is narrower than half of the central portion, and the outflow of heat to the outer periphery is small, so that the effect of increasing the temperature of the wafer mounting surface 3 is further increased. If a member having a low thermal conductivity is disposed in the peripheral portion, the effect of increasing the temperature of the wafer mounting surface 3 appears more greatly. Therefore, it is more preferable to dispose the region 6c in the peripheral portion.

  Further, when the region 6c having a small thermal conductivity is arranged on the entire circumference of the annular region in the peripheral portion, it is preferable because the temperature of the entire periphery of the peripheral portion of the wafer mounting surface 3 is increased. In the conventional wafer holder 100, the peripheral portion of the wafer mounting surface 3 tends to decrease in temperature because the distance from the center of the plasma above the heater member 8 and the wafer tends to be low. Although the difference is one of the factors, the temperature difference within the wafer surface can be reduced by arranging the region 6c in an annular shape.

  Further, since the region 6c is a peripheral portion of the wafer holder 1, the base member 4 and the heater member 8 are integrated or bonded, or after the base member 4, the heater member 8, and the plate-like ceramic body 2 are integrated. Alternatively, after bonding, a part of the periphery of the intervening layer 6 can be replaced with a low heat conductive member. Further, it is possible to adjust the in-plane temperature difference of the wafer mounting surface 3 to be small and uniform while confirming the temperature distribution of the wafer mounting surface 3, so that the in-plane temperature difference of the wafer is further adjusted to be small. Can do.

  Moreover, it is preferable that the area | region 6b with small heat conductivity is the space | gap 6d. When the region 6d having a low thermal conductivity is disposed in the intervening layer 6, the region 6d is disposed so that the temperature difference between the wafer mounting surfaces 3 is reduced. The region 6d and the intervening layer 6 excluding the region 6d are disposed. The greater the difference in thermal conductivity, the greater the range in which the temperature difference can be adjusted. It is preferable to use silicon resin or polyimide resin as the intervening layer 6, but as a material having a small thermal conductivity to be disposed in the region 6 d of these intervening layers 6, a gap having a large thermal conductivity difference from the intervening layer 6 is used. By using the region 6d, the function of the region 6d can be effectively exhibited. In particular, when a region 6d composed of a gap is disposed around the intervening layer 6, the shape of the region 6d is hardly changed even in a gap having a small shape maintaining function, and the durability is excellent and the temperature difference of the wafer mounting surface 3 is corrected. The action is large and preferable.

  Further, the region 6b having a different thermal conductivity of the intervening layer 6 of the present invention is arranged as a region 6b having a high thermal conductivity corresponding to a portion where the temperature is high with respect to the temperature distribution during heating by the heater member 8. Is preferred. There is a possibility that a high temperature portion may be generated on the wafer mounting surface 3 so as to face a portion where the in-plane temperature of the heater member 8 is high, but from the heater member 8 that is transmitted to a portion that tends to be high temperature in the surface of the wafer mounting surface 3. By reducing the amount of heat, the in-plane temperature difference of the wafer mounting surface 3 can be reduced. The action of lowering the temperature of the high temperature portion of the wafer mounting surface 3 by transferring more heat generated from the high temperature portion of the wafer mounting surface 3 and the high temperature portion of the heater member 8 to the base member 4. The in-plane temperature difference of the wafer mounting surface 3 can be reduced. Then, by disposing a region 6b having a high thermal conductivity in the intervening layer 6 between the heater member 8 and the base member 4 so as to face a portion where the temperature of the wafer placement surface 3 is high, the heat from the heater member 8 is increased. It is preferable that the temperature difference of the wafer mounting surface 3 can be made small and constant by flowing to the base member 4 and lowering the temperature of the heater member 8.

  The wafer holder 1 of the present invention preferably includes an adsorption electrode 9 for adsorbing the wafer to the wafer mounting surface 3 on the other main surface or inside of the plate-like ceramic body 2. By adsorbing the wafer to the wafer placement surface 3 by electrostatic force, the adhesion between the wafer placement surface 3 and the wafer is improved, and the heat of the wafer placement surface 3 is transferred to the wafer more quickly. The temperature distribution on the surface 3 is reflected on the temperature distribution on the wafer surface as it is, and the temperature difference in the wafer surface becomes smaller, which is preferable.

  Next, a method for manufacturing the wafer holder 1 of the present invention will be described using the wafer holder 1 shown in FIG. 9 as an example. The wafer holder 1 of the present invention includes a plate-shaped ceramic body 2 having an upper surface as a wafer mounting surface 3, a base member 4 that cools the plate-shaped ceramic body 2 from the lower surface side, a plate-shaped ceramic body 2, and a base member 4. And a step of preparing a plate-like heater member 8 that heats the plate-like ceramic body 2 from the lower surface side, a step of measuring the temperature distribution by heating the heater member 8, and the heater member 8 The region 6b having a low thermal conductivity is disposed corresponding to a portion having a low temperature with respect to the temperature distribution, or the intervening layer 6 having a region 6b having a large thermal conductivity corresponding to a portion having a high temperature is disposed. The heater member 8 can be manufactured on the upper surface of the base member 4, and the plate-shaped ceramic body 2 can be manufactured on the upper surface of the heater member 8 via the intervening layer 7.

  Specifically, the plate-like ceramic body 2 provided with the adsorption electrode 9, the plate-like heater member 8, and the base member 4 provided with the cooling passage 5 are prepared. Next, an adhesive such as silicon or epoxy is applied to the surface of the base member 4 a plurality of times by screen printing or the like, laminated, and cured by heating to form the intervening layer 6. Then, after the heater member 8 alone generates heat, the temperature distribution on the surface is measured, and a part of the intervening layer 6 is cut away using a tool such as a cutter knife so as to face the high temperature portion. An adhesive such as silicon or epoxy having a thermal conductivity smaller than that of the intervening layer 6a, or a sheet-like resin is disposed in the cut portion. This portion becomes a region 6b having different thermal conductivity. The region 6b is filled with a member having a low thermal conductivity. However, if there is no risk of deformation of the wafer mounting surface 3, the region 6b can be used as a gap. Next, the same adhesive as silicon or epoxy may be applied to the upper surface of the intervening layer 6 by screen printing or the like. Next, the heater member 8 is bonded onto the intervening layer 6 under reduced pressure. The reason for bonding under reduced pressure is to prevent voids at the bonding interface and to prevent variation in heat conduction. A silicon adhesive is uniformly applied to the upper surface of the heater member 8 by screen printing or the like to form the intervening layer 7. Further, the wafer holder 1 can be produced by bonding the plate-like ceramic body 2 provided with the adsorption electrode 9 on the intervening layer 7.

  Moreover, the in-plane temperature difference of the wafer mounting surface 3 can be further reduced by adjusting the peripheral portion of the intervening layer 6 of the produced wafer holder 1. A method for adjusting the peripheral portion of the intervening layer 6 will be described below. First, the heater member 8 is energized and heated while flowing a cooling medium through the cooling passage 5 of the base member 4. Then, the voltage applied to the heater member 8 is adjusted so that the average temperature of the wafer mounting surface 3 becomes, for example, 60 ° C. while observing the temperature distribution of the wafer mounting surface 3 with a thermoviewer. Thereafter, the in-plane temperature of the wafer placement surface 3 is measured. When the temperature of a part of the outer peripheral part of the wafer placement surface 3 is low, a part of the peripheral part of the opposing intervening layer 6 is cut out using a tool such as a cutter knife. Then, the temperature distribution on the wafer placement surface 3 is again measured in the same manner using a thermoviewer. Adjusting the temperature difference in the surface of the wafer mounting surface 3 to be small by forming regions 6c and 6d having low thermal conductivity in the intervening layer 6 so as to face the low temperature portion of the wafer mounting surface 3. Can do.

  Moreover, although this embodiment demonstrated what contained the heater member 8, the same effect is acquired also when the heater member 8 is not contained.

  As mentioned above, although embodiment of this invention was shown, this invention is not limited only to embodiment mentioned above, It cannot be overemphasized that it can apply also to what was improved and changed in the range which does not deviate from the summary. .

  Here, ten wafer holders 1 of the present invention shown in FIG. 1 and ten conventional wafer holders 100 shown in FIG. 1 and No. 2. And the temperature distribution of each wafer mounting surface 3 was measured.

  As the plate-like ceramic body 2, an aluminum nitride sintered body having a plate thickness of 2 mm and a diameter of 200 mm was used. Then, a pair of adsorption electrodes 9 made of Ni was formed on one surface of the plate-like ceramic body 2 by a plating method. Further, an aluminum base member 4 having a cooling passage 5 as shown in FIG. 2 was prepared.

  The plate-shaped ceramic body 2 and the base member 4 are the same as those of the experimental group No. The same thing was used for 1 and 2.

  In addition, the silicon sheet A having a thermal conductivity of 0.53 W / (m · K) and about half the thermal conductivity of the silicon sheet A, the thermal conductivity being 0.27 W / (m · K). Silicon sheet B was prepared as an intervening layer.

  Experiment Group No. Sample No. 1 In Nos. 10 to 19, the silicon sheet A was used as the intervening layer 6a, and the silicon sheet B having low thermal conductivity was arranged as the region 6b having low thermal conductivity so as to oppose the cooling passage 5.

  The experimental group No. Sample No. 2 20-29 arrange | positioned the silicon sheet A as the intervening layer 60. FIG.

  Next, a method for evaluating the produced wafer holder will be described.

Experiment Group No. 1 and no. Each wafer holder of No. 2 heated the wafer mounting surface to about 60 ° C. by lamp heating. Then, the cooling water controlled to the temperature of 30 degreeC was poured through the base member 4, and the temperature of the wafer mounting surface after 5 seconds was measured. A value obtained by subtracting the minimum temperature from the maximum temperature of the in-plane temperature of the wafer mounting surface was defined as the in-plane maximum temperature difference. The measured results are shown in Table 1.

  An experimental group No. in which a plate-shaped ceramic body 2 having an upper surface as a wafer mounting surface 3 is interposed on an upper surface of a base member that cools the plate-shaped ceramic body 2 from the lower surface side through intervening layers having regions having different thermal conductivities. . 1 shows that the average value of the in-plane maximum temperature difference in the wafer mounting surface 3 is 2.9 ° C. It was found that 7 samples out of 10 had a small in-plane maximum temperature difference of 3 ° C. or less as compared with 3.6 ° C. of 2 and an excellent manufacturing yield of 70%. This is because by arranging the region 6b having different heat conduction in the intervening layer 6, the local cooling of the wafer mounting surface 3 can be suppressed and the in-plane temperature difference of the wafer mounting surface 3 can be reduced. is there.

  On the other hand, the experiment group No. 2 shows that the maximum in-plane temperature difference in the wafer mounting surface 3 is as large as 2.7 to 4.7 ° C., and the number of samples that were 3 ° C. or less is as small as 4 out of 10 samples and the manufacturing yield is 40%. It was.

  Next, the plate-like ceramic body 2 and the base member 4 were the same as those in Example 1, and the heater member 8 was disposed between the plate-like ceramic body 2 and the base member 4.

  The intervening layer 7 is disposed between the plate-like ceramic body 2 and the heater member 8, and the intervening layer 6 is disposed between the heater member 8 and the base member 4. A region 6b and a region 7b having different thermal conductivities are arranged in either the intervening layer 6 or the intervening layer 7. The regions 6b and 7b were shaped along the cooling passage 5 as in the first embodiment. In addition, the silicon sheet B was used for the region 6b as in Example 1, and the silicon sheet A was used for the other intervening layer 6a. For the region 7b, a silicon sheet C having a thermal conductivity of 1.06 W / (m · K) was used.

  Experiment Group No. Sample No. 3 30-39 arrange | positioned the area | region 7b in the intervening layer 7 like FIG. 10, and the intervening layer 6 used the sheet | seat of uniform thermal conductivity.

  The experimental group No. Sample No. 4 40-49 arrange | positioned the area | region 6b in the intervening layer 6 like FIG.

Evaluation was performed in the same manner as in Example 1. The experimental results are shown in Table 2.

  Experiment Group No. 3 shows that the average value of the in-plane maximum temperature difference of the wafer mounting surface 3 is 2.9 ° C., the number of samples in which the in-plane maximum temperature difference exceeds 3 ° C. is 8 out of 10 samples, and the production yield is 80%. It was. This production yield of 80% is determined by the experiment group no. It was found that the production yield of No. 1 was preferable to be larger than 70%.

  Experiment Group No. No. 4 shows that the average value of the in-plane maximum temperature difference of the wafer mounting surface 3 is as small as 2.6 ° C., and it is further preferable that 9 out of 10 samples are 3 ° C. or less.

  Experiment Group No. 3 for the experimental group no. 4 is that a member having different heat conduction is disposed between the heater member 8 and the base member 4 that are heat sources, so that it becomes easy to control the amount of heat in the direction of the wafer mounting surface 3, and the maximum in-plane is more efficient. It is thought that the temperature difference could be reduced.

  Although the silicon layers were used for the intervening layers 6 and 7 in Examples 1 and 2, in this example, the experiment was performed by changing the silicon sheet to a silicon adhesive. The wafer holder 1 manufactured using the intervening layers 6 and 7 made of silicon adhesive is the test group no. It was set to 5. The experimental group No. 1 prepared in Example 2 was used. 4 wafer support 1.

  Experiment Group No. The same plate-like ceramic body 2 and base member 4 as those in Example 1 were used. Sample No. 50 to 59 are the experimental group Nos. Shown in FIG. The arrangement of members was the same as in the case of No. 4. For the intervening layers 6 and 7, silicon adhesive A having a thermal conductivity of 0.53 W / (m · K) was used. The thickness of the intervening layer was 700 μm as in Examples 1 and 2. Further, the adhesive B of 0.27 W / (m · K), which is about a half of the thermal conductivity of the silicon adhesive A, was used for the region 6b having a low thermal conductivity.

  Specifically, the intervening layer 6a shown in FIG. 3 is made the silicon adhesive A and the interposing layer 6b is made the silicon adhesive B so as to face the cooling passage 5 shown in FIG. In addition, the annular region in the peripheral portion was replaced with the silicon adhesive B also in the outer peripheral portion.

The evaluation method was the same as in Example 2. The experimental results are shown in Table 3.

  Experiment Group No. The average value of the maximum in-plane temperature difference of 4 is 2.6 ° C. It was found that the average value of the maximum in-plane temperature difference of 5 was as small as 2.3 ° C., which was preferable. The experimental group No. No. 4 has 9 samples out of 10 samples having a maximum in-plane temperature difference of 3 ° C. or less. No. 5 was found to have excellent characteristics in all 10 out of 10 samples having a maximum in-plane temperature difference of 3 ° C. or less. This is presumably because the intervening layer 6 is made of an adhesive, so that no gap due to the thickness variation of the sheet as in the case of being made of a silicon sheet occurs on the boundary surface of the intervening layer.

  Next, the temperature distribution of the heater member 8 alone was measured in advance. Then, a part of the intervening layer 6 facing the low temperature portion was replaced with the silicon adhesive B from the silicon adhesive A.

  The experimental group No. The sample of No. 6 is an experiment group No. shown in FIG. The arrangement of the members was the same as in the case of 5. In addition, the region 6b (silicone adhesive B) having a different thermal conductivity is arranged in such a manner that a region having a low thermal conductivity is provided in the intervening layer 6 facing the low temperature portion in consideration of the temperature distribution of the cooling passage and the heater member. Arranged.

The evaluation method is the same as in Example 2. The experimental results are shown in Table 4.

  Experiment Group No. In comparison with the experimental group No. 6, the average value of the in-plane maximum temperature difference was reduced from 2.3 ° C. to 1.9 ° C., and the number of samples in which the in-plane maximum temperature difference was 3 ° C. or less was 10 out of 10, more preferably I understood. This is because the temperature distribution of the heater member 8 is confirmed individually in advance, so that the positions where the regions 6b having different heat conduction are arranged in the intervening layer 6 combined with the heater member 8 are compared one-on-one. This is because the temperature can be adjusted individually.

  Next, the experimental group No. manufactured in Example 4 was used. A wafer holder 1 was produced in the same manner as in FIG. Then, cooling water was passed through the cooling passage of the wafer holder 1, the heater was energized and heated, and the temperature distribution on the wafer placement surface 3 was measured with a thermoviewer. Then, a part of the intervening layer at the periphery of the wafer mounting surface 3 having a low temperature is cut off from the outer peripheral side, and a silicon adhesive C (thermal conductivity 0.14 W / (m · K)) having a lower thermal conductivity is cut there. ) Is embedded as a region 6c having different heat conduction as shown in FIG. The size was 0.2 to 1 mm deep in the central direction.

  In addition, the same thing as Example 1 was used for the plate-shaped ceramic body 2 and the base member 4.

The evaluation method was the same as in Example 2. The results are shown in Table 5.

  Experiment Group No. The average value of the in-plane maximum temperature difference of the wafer mounting surface 3 in FIG. 7 was found to be as small as 1.6 ° C. and excellent. Further, all the samples were excellent because the maximum in-plane temperature difference was 3 ° C. or less and the production yield was 100%. This is presumably because the region 6c having different thermal conductivity could be disposed in the intervening layer 6 while confirming the temperature distribution on the wafer mounting surface 3.

  Next, the experimental group No. 4 of Example 4 was used. A wafer holder 1 was produced in the same manner as in FIG. Then, similarly to Example 5, the temperature of the wafer mounting surface 3 of the produced wafer holder 1 was measured. And the intervening layer of the low temperature part in the peripheral part of the wafer mounting surface 3 was cut off. The cut portion was used as it is as the region 6d in FIG.

Evaluation was performed in the same manner as in Example 2. The results are shown in Table 6.

  As shown in FIG. 11, the experimental group No. 1 in which the peripheral region 6 of the intervening layer was filled with an adhesive having a low thermal conductivity. In contrast to the maximum in-plane temperature difference of 1.6 ° C., the experimental group No. 1 provided with voids around the intervening layer as shown in FIG. It was found that the in-plane maximum temperature difference of the sample No. 8 was as small as 1.4 ° C. and preferable.

(A) is a schematic perspective view which shows an example of embodiment of the wafer holder of this invention, (b) is the XX schematic sectional drawing. It is a schematic top view which shows the schematic shape of the cooling channel | path of the wafer holder of this invention. It is a schematic top view which shows the intervening layer which has an area | region from which the heat conductivity of this invention differs. It is a schematic top view which shows the temperature distribution of the wafer mounting surface which has arrange | positioned the intervening layer which has the area | region where the thermal conductivity of this invention differs. It is a schematic sectional drawing which shows the other example of embodiment of the wafer holder of this invention. It is a schematic top view which shows the temperature distribution of the heater member single-piece | unit of this invention. It is a schematic top view which shows the intervening layer which has an area | region from which the heat conductivity of this invention differs. It is a schematic top view which shows the temperature distribution of the wafer mounting surface which has arrange | positioned the area | region where the heat conductivity of this invention differs. It is a schematic sectional drawing which shows the other wafer holding body of this invention. It is a schematic sectional drawing which shows the other wafer holding body of this invention. It is a schematic sectional drawing which shows the other wafer holding body of this invention. It is a schematic sectional drawing which shows the other wafer holding body of this invention. It is sectional drawing which shows the conventional wafer holder. It is sectional drawing which shows the other conventional wafer holder. It is sectional drawing which shows the other conventional wafer holder. It is sectional drawing which shows the other conventional wafer holder. It is a schematic top view which shows the temperature distribution of the mounting surface of the conventional wafer holder.

Explanation of symbols

1: Wafer holder 2: Plate-like ceramic body 3: Wafer mounting surface 4: Base member 5: Cooling passage 6: Intervening layer 7a: Intervening layer 6b in a portion excluding regions having different thermal conductivities: Different thermal conductivities Area 6c: Area 6d with low thermal conductivity 6d: Gaps 7: Intervening layer 7a: Intervening layer 7b other than areas with different thermal conductivity 7: Area with different thermal conductivity 8: Heater member 9: Adsorption electrode 60: Interposition Layer 100: Wafer holder

Claims (10)

A plate-like ceramic body having an upper surface as a wafer mounting surface is disposed on an upper surface of a base member that cools the plate-like ceramic body from the lower surface side with an intervening layer having regions having different thermal conductivities. Wafer holder. The wafer holder according to claim 1, wherein a plate-like heater member for heating the plate-like ceramic body from the lower surface side is disposed between the plate-like ceramic body and the base member. The wafer holder according to claim 2, wherein the intervening layer is disposed between the heater member and the base member. The wafer holder according to claim 1, wherein the intervening layer is made of an adhesive. The region having different thermal conductivity of the intervening layer is arranged as a region having low thermal conductivity corresponding to a portion having a low temperature with respect to a temperature distribution during heating by the heater member. The wafer holder in any one of 2-4. 6. The wafer holder according to claim 5, wherein the intervening layer includes a region having a small thermal conductivity in a peripheral portion between the heater member and the base member. The wafer holder according to claim 6, wherein the region having a low thermal conductivity is a gap. The region having different thermal conductivity of the intervening layer is arranged as a region having high thermal conductivity corresponding to a portion having a high temperature with respect to a temperature distribution during heating by the heater member. The wafer holder in any one of 2-4. The wafer holder according to claim 1, further comprising an adsorption electrode for adsorbing a wafer to the wafer mounting surface on a lower surface or inside of the plate-like ceramic body. A plate-shaped ceramic body having an upper surface as a wafer mounting surface, a base member for cooling the plate-shaped ceramic body from the lower surface side, and disposed between the plate-shaped ceramic body and the base member. A step of preparing a plate-like heater member for heating the heater member from the lower surface side, a step of measuring the temperature distribution with the heater member in a heated state, and a portion where the temperature of the heater member is lower than the temperature distribution Arranging the heater member on the upper surface of the base member through an intervening layer in which a region having a low thermal conductivity is arranged or a region having a high thermal conductivity is arranged corresponding to a portion having a high temperature. And a step of disposing the plate-like ceramic body on the upper surface of the heater member via an intervening layer.

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