Substrate fixing device

Abstract

To provide a substrate fixing device that can improve the temperature uniformity of the mounting surface.SOLUTION: A substrate fixing device 10 has a ceramic base plate 20, a ceramic electrostatic chuck 80 with a mounting surface 81A on which the object to be adsorbed is mounted, and an adhesive layer 70 bonding the base plate 20 and the electrostatic chuck 80.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a substrate fixing device. [Background technology]

[0002] Conventionally, film forming apparatuses (e.g., CVD apparatuses and PVD apparatuses) and plasma etching apparatuses used in manufacturing semiconductor devices such as ICs and LSIs have a substrate fixing device for precisely holding a substrate such as a silicon wafer in a vacuum processing chamber. In the substrate fixing device, a ceramic electrostatic chuck is bonded to a metal base plate by an adhesive layer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-23088 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a conventional substrate fixing device, the temperature of the mounting surface of the electrostatic chuck on which the object to be clamped is mounted may vary. Specifically, when the substrate fixing device is exposed to a low temperature of about -60°C or a high temperature of about 180°C, a large difference occurs between the amount of thermal deformation of the electrostatic chuck and the amount of thermal deformation of the base plate. This causes a large stress to act on the adhesive layer, which may cause cohesive failure in the adhesive layer. When cohesive failure occurs in the adhesive layer, the in-plane uniformity of the thermal resistance of the adhesive layer decreases, causing the temperature of the mounting surface of the electrostatic chuck to vary. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a ceramic base plate, a ceramic electrostatic chuck having a mounting surface on which an object to be attracted is placed, and an adhesive layer that bonds the base plate and the electrostatic chuck. Effect of the Invention

[0006] Advantageous Effects of Invention According to one aspect of the present invention, an effect is achieved in that the temperature uniformity of the mounting surface can be improved. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a substrate fixing device according to one embodiment. [Diagram 2] FIG. 2 is an enlarged cross-sectional view showing a portion of the base plate shown in FIG. [Diagram 3] FIG. 3 is a schematic cross-sectional view showing a method for manufacturing a base plate. [Figure 4] FIG. 4 is a schematic cross-sectional view showing a method for manufacturing a base plate. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing a method for manufacturing a base plate. [Figure 6] FIG. 6 is a schematic cross-sectional view showing a modified example of the substrate fixing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment will be described with reference to the accompanying drawings. In addition, for convenience, the attached drawings may show characteristic parts in an enlarged manner to make the features easier to understand, and the dimensional ratios of each component may differ from drawing to drawing. In addition, in the cross-sectional views, the hatching of some components is shown as a matte pattern and the hatching of some components is omitted in order to make the cross-sectional structure of each component easier to understand. In addition, the "up-down direction" and "left-right direction" in this specification are the directions when the direction in which the symbols indicating each component in each drawing can be correctly read is taken as the normal position.

[0009] (Overall configuration of substrate fixing device 10) 1, the substrate fixing device 10 includes a ceramic base plate 20, an adhesive layer 70, and a ceramic electrostatic chuck 80. The electrostatic chuck 80 is fixed to the upper surface of the base plate 20 by the adhesive layer 70. The substrate fixing device 10 is a device that attracts and holds a substrate (not shown), which is an object to be attracted, by the electrostatic chuck 80 mounted on the upper surface of the base plate 20. An example of the substrate is a silicon wafer. The diameter of the substrate can be, for example, about 8 inches, 12 inches, or 18 inches.

[0010] The base plate 20 and the electrostatic chuck 80 may be made of ceramic materials such as aluminum oxide, aluminum nitride, and silicon nitride. The base plate 20 and the electrostatic chuck 80 may be made of the same ceramic material or different ceramic materials. For example, the base plate 20 and the electrostatic chuck 80 may be made of ceramic materials mainly composed of the same material, but may have different purities. In this specification, the term "main component" refers to a component that occupies 90% by weight or more of the components contained in the target portion. The base plate 20 of this embodiment is made of a ceramic material mainly composed of aluminum oxide. The electrostatic chuck 80 of this embodiment is made of a ceramic material mainly composed of aluminum oxide, and has a higher purity of aluminum oxide than the base plate 20. The base plate 20 preferably has an aluminum oxide purity of 90% or more, and more preferably has an aluminum oxide purity of 94% or more. The electrostatic chuck 80 preferably has an aluminum oxide purity of 95% or more, and more preferably has an aluminum oxide purity of 99.5% or more. By forming electrostatic chuck 80 from high-purity aluminum oxide in this manner, it is possible to reduce the temperature dependency of the insulation resistance in electrostatic chuck 80, and to suppress a decrease in insulation resistance due to an increase in temperature. Note that a purity of 99.5% or more indicates that the electrostatic chuck is formed without adding a sintering aid. Also, a purity of 99.5% or more means that the electrostatic chuck may contain unintended impurities during the manufacturing process, etc.

[0011] (Configuration of base plate 20) The base plate 20 is a base (base platform) for mounting the electrostatic chuck 80. The base plate 20 has the rigidity for supporting the electrostatic chuck 80. The thickness of the base plate 20 may be, for example, about 20 mm to 50 mm.

[0012] The base plate 20 has a lower portion 21 and an upper portion 22 stacked on an upper surface of the lower portion 21. The lower portion 21 is formed, for example, in a disk shape. The upper portion 22 is formed, for example, in a disk shape. The upper portion 22 is arranged, for example, concentrically on the upper surface of the lower portion 21. The upper portion 22 has a smaller size than the lower portion 21 in a plan view. The diameter of the upper portion 22 is smaller than the diameter of the lower portion 21. The upper portion 22 is formed so as to protrude upward from the upper surface of the lower portion 21.

[0013] For example, a cooling path 30 is provided inside the base plate 20. The cooling path 30 has an inlet 31 provided at one end and an outlet 32 ​​provided at the other end. The cooling path 30 is connected to, for example, a cooling medium control device (not shown) provided outside the substrate fixing device 10. The cooling medium control device introduces a cooling medium from the inlet 31 to the cooling path 30 and discharges the cooling medium from the outlet 32. The cooling medium is circulated through the cooling path 30 to cool the base plate 20, thereby cooling the substrate attracted to the electrostatic chuck 80. Note that, for example, water or Galden can be used as the cooling medium.

[0014] For example, a gas flow passage 40 is provided inside the base plate 20. The gas flow passage 40 is formed so as to penetrate the base plate 20 in the thickness direction (the vertical direction in the figure). Specifically, the gas flow passage 40 penetrates from the upper surface of the upper portion 22 to the lower surface of the lower portion 21. For example, a gas for cooling the substrate attracted to the electrostatic chuck 80 is introduced into the gas flow passage 40. An inert gas can be used as the cooling gas. For example, helium (He) gas or argon (Ar) gas can be used as the inert gas.

[0015] The base plate 20 has a structure in which, for example, multiple layers (three layers in this case) of ceramic plates 51, 52, and 53 are laminated. Each of the ceramic plates 51, 52, and 53 is a sintered body formed by sintering a green sheet made of, for example, a mixture of aluminum oxide and an organic material. The ceramic plate 52 is bonded to the upper surface of the ceramic plate 51, and the ceramic plate 53 is bonded to the upper surface of the ceramic plate 52. The bonding between the ceramic plate 51 and the ceramic plate 52, and the bonding between the ceramic plate 52 and the ceramic plate 53 can be performed by, for example, brazing.

[0016] The ceramic plate 51 constitutes, for example, the lower portion 21 of the base plate 20. The ceramic plate 51 is formed, for example, in a disk shape. The ceramic plate 51 has, for example, an inlet portion 31, an outlet portion 32, and a recess portion 33 that constitute the cooling path 30.

[0017] The recess 33 is formed so as to be recessed downward from the upper surface of the ceramic plate 51. The recess 33 is formed so as to open upward from the ceramic plate 51. The introduction portion 31 is formed so as to be recessed upward from the lower surface of the ceramic plate 51 and to be in communication with the recess 33. The introduction portion 31 is formed so as to be in communication with the lower surface of the ceramic plate 51. The discharge portion 32 is formed so as to be recessed upward from the lower surface of the ceramic plate 51 and to be in communication with the recess 33. The discharge portion 32 is formed so as to be in communication with the lower surface of the ceramic plate 51.

[0018] 2, the ceramic plate 51 has holes 41 that form the gas flow passages 40. The holes 41 are formed so as to penetrate the ceramic plate 51 in the thickness direction. The holes 41 are formed so as to open to the upper side of the ceramic plate 51 and also to open to the lower side of the ceramic plate 51. The holes 41 are formed so as to extend linearly along the thickness direction of the ceramic plate 51, for example.

[0019] A conductive pattern 61 is provided on the upper surface of the ceramic plate 51. The conductive pattern 61 is provided so as to overlap with the ceramic plates 52 and 53 in a plan view, for example. The conductive pattern 61 is provided so as not to overlap with the recesses 33 and the holes 41 in a plan view, for example.

[0020] The ceramic plates 52 and 53, for example, constitute the upper portion 22 of the base plate 20. The ceramic plates 52 and 53 are formed, for example, in a disk shape. The ceramic plates 52 and 53 have a smaller size than the ceramic plate 51 in a plan view. The ceramic plate 52 has the same size as the ceramic plate 53 in a plan view.

[0021] Ceramic plate 52 is provided so as to close the opening of recess 33 of ceramic plate 51. Cooling path 30 is thus formed by ceramic plate 52 closing the opening of recess 33, recess 33, inlet portion 31, and outlet portion 32 (see FIG. 1).

[0022] The ceramic plate 52 has holes 42, 43 which form the gas flow passage 40. The holes 42 and 43 are formed to communicate with each other. The holes 42 and 43 are formed to penetrate the ceramic plate 52 in the thickness direction in cooperation with each other. The hole 42 is formed to be recessed upward from the lower surface of the ceramic plate 52. The hole 42 is formed to open downward of the ceramic plate 52. The hole 42 is formed to communicate with the hole 41 of the ceramic plate 51. The hole 42 is formed to extend linearly along the thickness direction of the ceramic plate 52, for example.

[0023] The hole portion 43 is formed so as to be recessed downward from the upper surface of the ceramic plate 52, and is formed so as to communicate with the hole portion 42. The hole portion 43 is formed so as to open upward from the ceramic plate 52. The hole portion 43 has a size larger than the hole portion 42 in a plan view. That is, the opening area of ​​the hole portion 43 is larger than the opening area of ​​the hole portion 42. The hole portion 43 is provided so as to overlap the entire hole portion 42 in a plan view. Furthermore, the ceramic plate 52 may be provided with a groove portion formed so as to be recessed downward from the upper surface of the ceramic plate 52.

[0024] A conductive pattern 62 is provided on the lower surface of the ceramic plate 52. The conductive pattern 62 is provided so as to overlap the conductive pattern 61 in a plan view, for example. The conductive pattern 62 is provided so as not to overlap the recess 33 and the holes 41, 42 in a plan view, for example. The conductive pattern 61 and the conductive pattern 62 are joined to each other by brazing using a brazing material (not shown) such as silver brazing. The conductive pattern 61 and the conductive pattern 62 are joined to each other, whereby the ceramic plate 51 and the ceramic plate 52 are joined to each other. As a result, the ceramic plate 52 is laminated on the upper surface of the ceramic plate 51.

[0025] A conductive pattern 63 is provided on the upper surface of the ceramic plate 52. The conductive pattern 63 is provided, for example, so as not to overlap the hole portion 43 in a plan view. For example, the conductive pattern 63 is formed so as to cover the entire upper surface of the ceramic plate 52.

[0026] The ceramic plate 53 has a hole 44 that constitutes the gas flow path 40. The hole 44 is formed so as to penetrate the ceramic plate 53 in the thickness direction. The hole 44 is formed so as to open to the upper side of the ceramic plate 53 and to open to the lower side of the ceramic plate 53. The hole 44 is formed so as to communicate with the hole 43 of the ceramic plate 52. The hole 44 is formed so as to extend linearly along the thickness direction of the ceramic plate 53, for example. The hole 44 has a size smaller than the hole 43, for example, in a plan view. That is, the opening area of ​​the hole 44 is smaller than the opening area of ​​the hole 43. The hole 44 is provided so that its entirety overlaps with the hole 43 in a plan view. For example, the hole 44 is provided at a position different from the hole 42 in a plan view.

[0027] A conductive pattern 64 is provided on the lower surface of the ceramic plate 53. The conductive pattern 64 is provided so as to overlap the conductive pattern 63 in a plan view, for example. The conductive pattern 64 is provided so as not to overlap the holes 43, 44 in a plan view, for example. The conductive pattern 63 and the conductive pattern 64 are joined to each other by brazing using a brazing material (not shown) such as silver brazing. The conductive pattern 63 and the conductive pattern 64 are joined to each other, whereby the ceramic plate 52 and the ceramic plate 53 are joined to each other. As a result, the ceramic plate 53 is laminated on the upper surface of the ceramic plate 52.

[0028] (Configuration of adhesive layer 70) 1, the adhesive layer 70 is provided between the base plate 20 and the electrostatic chuck 80. The adhesive layer 70 bonds the base plate 20 and the electrostatic chuck 80. The adhesive layer 70 is formed, for example, so as to cover the upper surface of the base plate 20, specifically, the entire upper surface of the ceramic plate 53 that constitutes the upper portion 22. The adhesive layer 70 is formed, for example, so as to cover the entire lower surface of the electrostatic chuck 80.

[0029] The adhesive layer 70 has, for example, an adhesive layer 71, an adhesive auxiliary layer 72 provided between the adhesive layer 71 and the base plate 20, and an adhesive auxiliary layer 73 provided between the adhesive layer 71 and the electrostatic chuck 80.

[0030] The adhesive layer 71 may be, for example, an adhesive made of a polymer compound. The adhesive layer 71 may be, for example, a silicone-based adhesive. The adhesive layer 71 functions, for example, as an adhesive for bonding the base plate 20 and the electrostatic chuck 80 together, and also functions as a heat-conducting member for conducting heat from the electrostatic chuck 80 to the base plate 20. The adhesive layer 71 may be, for example, a material with high thermal conductivity. The adhesive layer 71 may have a thickness of, for example, about 0.05 mm to 2.0 mm.

[0031] The adhesive auxiliary layer 72 is provided to increase the adhesive strength between the base plate 20 and the adhesive layer 71. The adhesive auxiliary layer 72 is in direct contact with the upper surface of the base plate 20 and also in direct contact with the lower surface of the adhesive layer 71. For example, a surface modifier, a coupling agent, or a polymer compound that easily interacts with the adhesive layer 71 can be used as the adhesive auxiliary layer 72. The adhesive auxiliary layer 72 is thinner than the adhesive layer 71, for example. The thickness of the adhesive auxiliary layer 72 can be, for example, about 0.001 mm to 3 mm.

[0032] The adhesive auxiliary layer 73 is provided to increase the adhesive strength between the electrostatic chuck 80 and the adhesive layer 71. The adhesive auxiliary layer 73 is in direct contact with the lower surface of the electrostatic chuck 80 and the upper surface of the adhesive layer 71. For example, a surface modifier, a coupling agent, or a polymer compound that easily interacts with the adhesive layer 71 can be used as the adhesive auxiliary layer 73. The material of the adhesive auxiliary layer 72 and the material of the adhesive auxiliary layer 73 may be, for example, the same material or different materials. The adhesive auxiliary layer 73 is, for example, thinner than the adhesive layer 71. The thickness of the adhesive auxiliary layer 73 can be, for example, about 0.001 mm to 3 mm.

[0033] The adhesive layer 70 has, for example, a gas flow path 74 penetrating the adhesive layer 70 in the thickness direction. The gas flow path 74 is formed so as to penetrate the adhesive auxiliary layer 72, the adhesive layer 71, and the adhesive auxiliary layer 73 in the thickness direction. The gas flow path 74 opens above the adhesive layer 70 and also opens below the adhesive layer 70. The gas flow path 74 is formed so as to communicate with the gas flow path 40 of the base plate 20.

[0034] (Configuration of electrostatic chuck 80) The electrostatic chuck 80 has a substrate body 81 and an electrode 82 built in the substrate body 81. The electrostatic chuck 80 is, for example, a Johnsen-Rahbek type electrostatic chuck. The electrostatic chuck 80 may be a Coulomb force type electrostatic chuck. The electrostatic chuck 80 is a holder that attracts and holds a substrate, which is an object to be attracted.

[0035] The substrate body 81 is formed, for example, in a disk shape. The diameter of the substrate body 81 may be, for example, equal to the diameter of the upper portion 22 of the base plate 20, or may be larger than the diameter of the upper portion 22. The diameter of the substrate body 81 in this embodiment is equal to the diameter of the upper portion 22. The diameter of the substrate body 81 may be, for example, about 150 mm to 500 mm. The thickness of the substrate body 81 may be, for example, about 0.5 mm to 10 mm.

[0036] The substrate body 81 has a mounting surface 81A (here, the upper surface) on which a substrate, which is an object to be attracted, is mounted. The substrate body 81 is, for example, a dielectric material. The substrate body 81 is, for example, a ceramic substrate formed by sintering a green sheet made of aluminum oxide.

[0037] The substrate body 81 is provided with, for example, a gas flow path 83. The gas flow path 83 is formed so as to penetrate the substrate body 81 in the thickness direction. The gas flow path 83 opens to the upper side of the substrate body 81 and also opens to the lower side of the substrate body 81. The gas flow path 83 communicates with the gas flow path 74 of the adhesive layer 70.

[0038] In the substrate fixing device 10, the gas flow path 40, the gas flow path 74, and the gas flow path 83 constitute the gas hole 11. The gas flow path 40, the gas flow path 74, and the gas flow path 83 communicate with each other, so that the gas hole 11 is formed to penetrate from the mounting surface 81A of the substrate body 81 to the lower surface of the base plate 20. In the gas hole 11, an inert gas is introduced into the gas hole 11 through the gas flow path 40, and the inert gas is discharged from the gas hole 11 through the gas flow path 83. The inert gas discharged from the gas flow path 83 can cool the substrate by, for example, filling the space between the lower surface of the substrate placed on the mounting surface 81A and the mounting surface 81A.

[0039] The electrode 82 is, for example, an electrostatic electrode for adsorbing the substrate placed on the mounting surface 81A. The electrode 82 is an electrode formed in a thin film shape. The electrode 82 is, for example, built into a portion located near the mounting surface 81A in the thickness direction of the substrate body 81. The electrode 82 is, for example, arranged on a plane parallel to the mounting surface 81A. The electrode 82 is, for example, electrically connected to an adsorption power source provided outside the substrate fixing device 10. When a predetermined voltage is applied from the adsorption power source to the electrode 82, the electrode 82 generates an electrostatic adsorption force between the electrode 82 and the substrate placed on the mounting surface 81A. This allows the substrate to be adsorbed and held on the mounting surface 81A. The adsorption and holding force of the electrostatic chuck 80 becomes stronger as the voltage applied to the electrode 82 becomes higher. The electrode 82 may be unipolar or bipolar. For example, tungsten (W) or molybdenum (Mo) can be used as the material of the electrode 82. Although each drawing shows one electrode 82, in reality it includes a plurality of electrodes arranged on the same plane.

[0040] In this embodiment, the gas flow path 40 is an example of a first gas flow path, the hole 41 is an example of a first hole, the holes 42 and 43 are examples of second holes, the hole 44 is an example of a third hole, and the gas flow path 83 is an example of a second gas flow path. The ceramic plate 51 is an example of a first ceramic plate, the ceramic plate 52 is an example of a second ceramic plate, and the ceramic plate 53 is an example of a third ceramic plate. The conductive pattern 61 is an example of a first conductive pattern, the conductive pattern 62 is an example of a second conductive pattern, the conductive pattern 63 is an example of a third conductive pattern, and the conductive pattern 64 is an example of a fourth conductive pattern. The adhesive auxiliary layer 72 is an example of a first adhesive auxiliary layer, the adhesive auxiliary layer 73 is an example of a second adhesive auxiliary layer, and the electrode 82 is an example of a first electrode.

[0041] (Manufacturing method of substrate fixing device 10) Next, a method for manufacturing the substrate fixing device 10 will be described. Here, a method for manufacturing the base plate 20 will be described in detail. For ease of explanation, the parts that will ultimately become the components of the base plate 20 will be described with the reference numerals of the final components.

[0042] 3, a ceramic plate 51 is prepared having a conductive pattern 61 for brazing formed on its upper surface. A ceramic plate 52 is prepared having a conductive pattern 62 for brazing formed on its lower surface and a conductive pattern 63 for brazing formed on its upper surface. A ceramic plate 53 is prepared having a conductive pattern 64 for brazing formed on its lower surface. These three ceramic plates 51, 52, 53 can be manufactured by, for example, a green sheet method.

[0043] 4, the inlet portion 31, the outlet portion 32 (see FIG. 1), and the recessed portion 33 are formed in the ceramic plate 51, and the hole portion 41 is also formed. The inlet portion 31, the outlet portion 32, the recessed portion 33, and the hole portion 41 can be formed by, for example, a laser processing method or a mechanical processing method.

[0044] 4, the holes 42 and the holes 43 are formed in the ceramic plate 52. The holes 42 and the holes 43 can be formed by, for example, a laser processing method or a mechanical processing method.

[0045] 4, the holes 44 are formed in the ceramic plate 53. The holes 44 can be formed by, for example, a laser processing method or a mechanical processing method. Next, ceramic plate 52 is placed above ceramic plate 51 with conductive pattern 62 facing conductive pattern 61. At this time, ceramic plates 51, 52 are aligned so that hole 42 overlaps with hole 41 in a plan view. Furthermore, ceramic plate 53 is placed above ceramic plate 52 with conductive pattern 64 facing conductive pattern 63. At this time, ceramic plates 52, 53 are aligned so that hole 44 overlaps with hole 43 in a plan view.

[0046] Next, in the process shown in FIG. 5, the conductive pattern 61 and the conductive pattern 62 are joined by brazing. As a result, the ceramic plate 52 can be joined to the upper surface of the ceramic plate 51. Furthermore, the conductive pattern 63 and the conductive pattern 64 are joined by brazing. As a result, the ceramic plate 53 can be joined to the upper surface of the ceramic plate 52. In this process, the opening of the recess 33 is blocked by the ceramic plate 52. As a result, the cooling path 30 is formed by the inlet portion 31 and the outlet portion 32 (see FIG. 1) formed in the ceramic plate 51, the recess 33, and the ceramic plate 52 blocking the opening of the recess 33. In addition, in this process, the hole 41 of the ceramic plate 51, the holes 42 and 43 of the ceramic plate 52, and the hole 44 of the ceramic plate 53 are communicated with each other to form the gas flow path 40.

[0047] By the above manufacturing steps, the base plate 20 shown in FIGS. 1 and 2 can be manufactured. Next, the effects of this embodiment will be described.

[0048] (1) The substrate fixing device 10 includes a ceramic base plate 20, a ceramic electrostatic chuck 80 having a mounting surface 81A on which an object to be attracted is mounted, and an adhesive layer 70 that bonds the base plate 20 and the electrostatic chuck 80.

[0049] According to this configuration, both the base plate 20 and the electrostatic chuck 80 are made of a ceramic material. Therefore, the difference in thermal expansion coefficient between the base plate 20 and the electrostatic chuck 80 can be made smaller than when the base plate 20 is made of a metal material such as an aluminum alloy. Therefore, even when the substrate fixing device 10 is exposed to a low temperature of about -60°C or a high temperature of about 180°C, a large difference between the thermal deformation amount of the base plate 20 and the thermal deformation amount of the electrostatic chuck 80 can be suppressed. As a result, it is possible to suitably suppress the application of a large stress to the adhesive layer 70 that bonds the base plate 20 and the electrostatic chuck 80, and therefore it is possible to suitably suppress the occurrence of cohesive failure in the adhesive layer 70. This makes it possible to suppress the decrease in the in-plane uniformity of the thermal resistance of the adhesive layer 70, and therefore it is possible to suppress the occurrence of variations in the temperature of the mounting surface 81A of the electrostatic chuck 80. Therefore, it is possible to improve the uniformity of the temperature of the mounting surface 81A of the electrostatic chuck 80, compared to when the base plate 20 is made of a metal material such as an aluminum alloy.

[0050] (2) Meanwhile, during operation of the substrate fixing device 10, the temperature of the base plate 20 and the temperature of the electrostatic chuck 80 may differ from each other. Here, in the substrate fixing device 10 of the present embodiment, an adhesive layer 70 is provided between the base plate 20 and the electrostatic chuck 80. Therefore, even if the temperatures of the base plate 20 and the electrostatic chuck 80 are different, the stress caused by the temperature difference can be suitably absorbed by the adhesive layer 70. As a result, it is possible to suitably prevent the base plate 20 and the electrostatic chuck 80 from being destroyed by the stress caused by the temperature difference between the base plate 20 and the electrostatic chuck 80.

[0051] In order to confirm the above-mentioned effect, the inventors of the present application conducted a simulation to analyze the stress generated inside the substrate holding device 10 when the substrate holding device 10 is in operation. Specifically, a simulation was performed on the stress generated inside the substrate fixing device 10 for an example model in which an adhesive layer 70 was provided between the base plate 20 and the electrostatic chuck 80, and a comparative example model in which the adhesive layer 70 was not provided. The simulation method was finite element analysis using Abaqus. Other simulation conditions were a stress-free temperature of 60°C, a surface temperature of 300°C, a cooling temperature of 50°C, and a thermal expansion coefficient of the base plate 20 and the electrostatic chuck 80 of 7.3 ppm / °C.

[0052] From such simulation, it was confirmed that the stress generated inside the substrate fixing device 10 is smaller in the example model provided with the adhesive layer 70 than in the comparative example model not provided with the adhesive layer 70. Specifically, the maximum principal stress in the example model was 0.26 to 0.28 times the maximum principal stress in the comparative example model. From such simulation results, it is found that the stress generated inside the substrate fixing device 10 can be reduced by providing the adhesive layer 70.

[0053] (3) The base plate 20 and the electrostatic chuck 80 are made of a ceramic material mainly composed of the same material. This makes it possible to further reduce the difference in thermal expansion coefficient between the base plate 20 and the electrostatic chuck 80. Therefore, even when the substrate fixing device 10 is exposed to a low temperature of about -60°C or a high temperature of about 180°C, it is possible to more effectively prevent a large stress from acting on the adhesive layer 70, and therefore it is possible to more effectively prevent the temperature of the mounting surface 81A of the electrostatic chuck 80 from varying.

[0054] (4) The ceramic base plate 20 is configured by a plurality of ceramic plates 51, 52, 53 joined together by brazing. In this configuration, the ceramic plates 51, 52, 53 are provided with conductive patterns 61, 62, 63, 64 for brazing. The ceramic plates 51, 52 are joined by the conductive patterns 61, 62 being joined by brazing, and the ceramic plates 52, 53 are joined by the conductive patterns 63, 64 being joined by brazing. The base plate 20 thus formed has a structure having the conductive patterns 61, 62, 63, 64. For this reason, the rigidity of the base plate 20 can be increased, for example, compared to a case in which the ceramic plates 51, 52, 53 are joined together by an adhesive.

[0055] (Other embodiments) The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0056] The structure of the substrate fixing device 10 in the above embodiment can be modified as appropriate. 6, a resin layer 90 may be provided between an adhesive layer 70 and an electrostatic chuck 80. An electrode 92 embedded in the resin layer 90 may be provided.

[0057] The resin layer 90 is laminated on the upper surface of the adhesive layer 70. The resin layer 90 of this modified example is laminated on the upper surface of the adhesive auxiliary layer 73. The resin layer 90 is, for example, an insulating layer that insulates the electrode 92 from the electrode 82. For example, epoxy resin or bismaleimide triazine resin can be used as the material of the resin layer 90. The resin layer 90 may contain a filler such as alumina or aluminum nitride. The thickness of the resin layer 90 can be, for example, about 100 μm to 150 μm.

[0058] The resin layer 90 is provided with, for example, a gas flow passage 91. The gas flow passage 91 is formed to penetrate the resin layer 90 in the thickness direction. The gas flow passage 91 opens to an upper portion of the resin layer 90 and also opens to a lower portion of the resin layer 90. The gas flow passage 91 communicates with the gas flow passage 74 of the adhesive layer 70 and also communicates with the gas flow passage 83 of the electrostatic chuck 80.

[0059] The electrode 92 is, for example, a heating element for heating a substrate placed on the mounting surface 81A. The electrode 92 is, for example, disposed on a plane parallel to the mounting surface 81A. The electrode 92 is, for example, electrically insulated from the electrode 82. The material of the electrode 92 may be, for example, copper (Cu), tungsten, nickel (Ni), or the like. The thickness of the electrode 92 may be, for example, about 20 μm to 100 μm. The electrode 92 may have, for example, a concentric circular pattern.

[0060] The electrode 92 is electrically connected to, for example, a heating power source provided outside the substrate fixing device 10. The electrode 92 generates heat in response to a voltage applied from the heating power source. The electrode 92 heats the mounting surface 81A of the electrostatic chuck 80 to a predetermined temperature. The electrode 92 can heat the mounting surface 81A to a temperature of, for example, about 250° C. to 300° C. The electrode 92 is an example of a second electrode.

[0061] The mounting surface 81A of the electrostatic chuck 80 in the above embodiment may be provided with an embossment. The adhesive auxiliary layer 72 in the substrate fixing device 10 of the above embodiment may be omitted. The adhesive auxiliary layer 73 in the substrate fixing device 10 of the above embodiment may be omitted.

[0062] The shape of the gas hole 11 in the substrate fixing device 10 of the above embodiment may be changed as appropriate. Also, the gas hole 11 may be omitted. The shape of the cooling passage 30 in the base plate 20 of the above embodiment may be changed as appropriate. Also, the cooling passage 30 may be omitted.

[0063] In the base plate 20 of the above embodiment, the ceramic plates 51, 52, and 53 are joined to each other by brazing, but this is not limited to the above. For example, the conductive patterns 61 and 62 may be joined to each other by a conductive adhesive, and the conductive patterns 63 and 64 may be joined to each other by a conductive adhesive. Also, the conductive patterns 61, 62, 63, and 64 may be omitted, and the ceramic plates 51, 52, and 53 may be joined to each other by an adhesive such as a silicone adhesive.

[0064] In the above embodiment, there is no particular limitation on the number of ceramic plates 51, 52, 53 in the base plate 20. For example, the base plate 20 may have one or two ceramic plates, or four or more ceramic plates.

[0065] In the manufacturing method of the above embodiment, the recesses 33 and the holes 41, 42, 43, 44 are formed in the ceramic plates 51, 52, 53 after the green sheets are fired, but the present invention is not limited to this. For example, the recesses 33 and the holes 41, 42, 43, 44 may be formed in the green sheets before firing, that is, in the green sheets before firing.

[0066] The substrate fixing device 10 in the above embodiment is applied to a semiconductor manufacturing device, for example, a dry etching device. An example of a dry etching device is a parallel plate type reactive ion etching device. The substrate fixing device 10 can also be applied to semiconductor manufacturing devices such as a plasma CVD (Chemical Vapor Deposition) device and a sputtering device. [Explanation of symbols]

[0067] 10 Board fixing device 11 Gas hole 20 Base Plate 30 Cooling path 33 Recess 40 Gas flow path (first gas flow path) 41 Hole (1st hole) 42,43 Hole (2nd hole) 44 Hole (3rd hole) 51 Ceramic plate (first ceramic plate) 52 Ceramic plate (second ceramic plate) 53 Ceramic plate (third ceramic plate) 61 Conductive pattern (first conductive pattern) 62 Conductive pattern (second conductive pattern) 63 Conductive pattern (third conductive pattern) 64 Conductive pattern (fourth conductive pattern) 70 Adhesive layer 71 Adhesive layer 72 Adhesion auxiliary layer (1st adhesion auxiliary layer) 73 Adhesion auxiliary layer (second adhesion auxiliary layer) 80 Electrostatic Chuck 81 Board body 81A Mounting surface 82 electrode (1st electrode) 83 Gas flow path (second gas flow path) 90 Resin layer 92 electrode (second electrode)

Claims

1. Ceramic base plate, a ceramic electrostatic chuck having a mounting surface on which an object to be attracted is mounted; an adhesive layer that adheres the base plate and the electrostatic chuck; A substrate fixing device having a

2. 2. The substrate fixing device according to claim 1, wherein the base plate has a structure in which a plurality of ceramic plates are laminated.

3. The plurality of ceramic plates include a first ceramic plate having a first conductive pattern formed on an upper surface thereof; a second ceramic plate having a second conductive pattern formed on a lower surface thereof and bonded to the first conductive pattern; The substrate fixing device according to claim 2 , wherein the second ceramic plate is bonded to the upper surface of the first ceramic plate through bonding between the first conductive pattern and the second conductive pattern.

4. The substrate fixing device according to claim 3 , wherein the first conductive pattern and the second conductive pattern are joined to each other by brazing.

5. the base plate has a cooling passage formed by a recess extending downward from an upper surface of the first ceramic plate and the second ceramic plate disposed so as to close an opening of the recess, the first conductive pattern is provided so as to overlap the second ceramic plate in a plan view, The substrate fixing device according to claim 3 , wherein the second conductive pattern is provided so as to overlap the first conductive pattern but not to overlap the recess in a plan view.

6. a third conductive pattern is formed on an upper surface of the second ceramic plate; the plurality of ceramic plates further include a third ceramic plate having a fourth conductive pattern formed on a lower surface thereof and bonded to the third conductive pattern; the third ceramic plate is bonded to an upper surface of the second ceramic plate through bonding between the third conductive pattern and the fourth conductive pattern; the base plate has a first gas flow passage penetrating the base plate in a thickness direction, the electrostatic chuck has a second gas passage communicating with the first gas passage, 4. The substrate fixing device according to claim 3, wherein the first gas flow path has a first hole portion penetrating the first ceramic plate in a thickness direction, a second hole portion penetrating the second ceramic plate in the thickness direction and communicating with the first hole portion, and a third hole portion penetrating the third ceramic plate in the thickness direction and communicating with the second hole portion.

7. The adhesive layer is an adhesive layer provided between the base plate and the electrostatic chuck; A first adhesive auxiliary layer provided between the adhesive layer and the base plate; The substrate fixing device according to claim 1 , further comprising: a second adhesive auxiliary layer provided between the adhesive layer and the electrostatic chuck.

8. The substrate fixing device of claim 1 , further comprising a first electrode embedded in the electrostatic chuck.

9. a resin layer provided between the electrostatic chuck and the adhesive layer; A second electrode embedded in the resin layer; The substrate fixing device of claim 1 further comprising:

10. 2. The substrate fixing device according to claim 1, wherein the base plate and the electrostatic chuck are made of a ceramic material containing the same material as a main component.

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