Substrate fixing device

Abstract

The invention provides a substrate fixing device capable of improving the uniformity of the temperature of a carrying surface. A substrate fixing device (10) is provided with: a ceramic base plate (20); a ceramic electrostatic chuck (70) having a mounting surface (71A) on which an object to be adsorbed is mounted; and a brazed part (80) that joins the base plate (20) and the electrostatic chuck (70). The base plate (20) is made of a ceramic material having a coefficient of thermal expansion of 0 + / -3 ppm / K at room temperature. The electrostatic chuck (70) is made of a ceramic material having a coefficient of thermal expansion of 0 + / -3 ppm / K at room temperature.

Description

Technical Field

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

[0002] Currently, film-forming equipment (e.g., CVD (Chemical Vapor Deposition) equipment and PVD (Physical Vapor Deposition) equipment) and plasma etching equipment used in the manufacture of semiconductor devices such as ICs and LSIs include substrate holding devices that precisely hold substrates such as silicon wafers within a vacuum processing chamber. This substrate holding device adheres a ceramic electrostatic chuck to a metal base plate using an adhesive layer (see, for example, Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-23088 Summary of the Invention

[0004] However, current substrate fixtures sometimes experience temperature fluctuations on the mounting surface of the electrostatic chuck, which holds the object being held. Specifically, when the substrate fixture is exposed to temperatures ranging from approximately -60°C to 180°C, a significant difference occurs between the thermal deformation of the electrostatic chuck and the base plate. This results in significant stress acting on the adhesive layer, sometimes causing cohesive failure. Cohesive failure reduces the in-plane uniformity of the adhesive layer's thermal resistance, causing temperature fluctuations on the mounting surface of the electrostatic chuck.

[0005] According to one aspect of the present invention, there is provided a ceramic base plate; a ceramic electrostatic chuck having a mounting surface for mounting an adsorbed object; and a first soldering portion joining the base plate and the electrostatic chuck, wherein the base plate has a thermal expansion coefficient of 0 at room temperature.

[0006] The electrostatic chuck is made of a ceramic material with a thermal expansion coefficient of 0 at room temperature.

[0007] Made of ceramic material with ±3ppm / K.

[0008] Effects of the Invention

[0009] According to one aspect of the present invention, the effect of improving the temperature uniformity of the mounting surface is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a schematic cross-sectional view showing a substrate fixing device according to one embodiment.

[0011] Figure 2 It is an enlarged representation Figure 1An enlarged cross-sectional view of a portion of a substrate holding device is shown.

[0012] Figure 3 This is a schematic cross-sectional view showing a method for manufacturing a substrate fixing device.

[0013] Figure 4 This is a schematic cross-sectional view showing a method for manufacturing a substrate fixing device.

[0014] Figure 5 This is a schematic cross-sectional view showing a method for manufacturing a substrate fixing device.

[0015] Figure 6 It is a schematic cross-sectional view showing a substrate fixing device according to a modified example. DETAILED DESCRIPTION

[0016] Hereinafter, one embodiment will be described with reference to the drawings.

[0017] In addition, for convenience, the drawings may sometimes show enlarged portions of features to facilitate understanding, and the dimensional ratios of various components may differ between the drawings. Furthermore, in the cross-sectional views, some components are hatched instead of hatched, while others are omitted, to facilitate understanding of the cross-sectional structure of each component. Furthermore, the terms "upward and downward directions" and "leftward and rightward directions" in this specification refer to directions when the symbols representing the components in the drawings are in the correct orientation.

[0018] (Overall Structure of Substrate Fixing Device 10)

[0019] like Figure 1 As shown, the substrate fixing device 10 includes: a base plate 20 made of ceramic; an electrostatic chuck 70 made of ceramic; and a soldering portion 80 that joins the base plate 20 and the electrostatic chuck 70. The substrate fixing device 10 includes, for example, a protective layer 90 that protects the soldering portion 80. The electrostatic chuck 70 is fixed to the upper surface of the base plate 20 by means of the soldering portion 80. The substrate fixing device 10 is a device that uses the electrostatic chuck 70 mounted on the upper surface of the base plate 20 to adsorb and hold a substrate (not shown) as an adsorption object. As the substrate, for example, a silicon wafer can be cited. In addition, the diameter of the substrate can be set to, for example, about 8 inches, 12 inches, or 18 inches.

[0020] As the material of the base plate 20 and the electrostatic chuck 70, a low thermal expansion ceramic material with a low thermal expansion coefficient can be used. As the low thermal expansion ceramic material, for example, a ceramic material with a thermal expansion coefficient of 0±3ppm / K at room temperature can be used. If the thermal expansion coefficient is 0±3ppm / K, the cohesive failure of the adhesive layer can be prevented. In addition, as the low thermal expansion ceramic material, it is more preferable to use a ceramic material with a thermal expansion coefficient of 0±1ppm / K at room temperature. That is, as the low thermal expansion ceramic material, a ceramic material with a thermal expansion rate of zero can be used. As the low thermal expansion ceramic material, for example, a ceramic material with cordierite (2MgO·2Al2O3·5SiO2) as the main component can be used. Here, the "main component" in this specification refers to a component that accounts for greater than or equal to 90% by weight of the components contained in the target part. The material of the base plate 20 and the material of the electrostatic chuck 70 can be the same ceramic material or different ceramic materials. In addition, the room temperature is in the temperature range of about 22°C to 26°C.

[0021] (Structure of the base plate 20)

[0022] Base plate 20 is a base (base) for mounting electrostatic chuck 70. Base plate 20 has rigidity for supporting electrostatic chuck 70. The thickness of base plate 20 can be set to approximately 20 mm to 50 mm, for example.

[0023] The base plate 20 includes a lower portion 21 and an upper portion 22 stacked on the upper surface of the lower portion 21. The lower portion 21 is formed in a disk shape, for example. The upper portion 22 is formed in a disk shape, for example. The upper portion 22 is concentrically arranged on the upper surface of the lower portion 21, for example. The planar dimensions of the upper portion 22 are smaller than the planar dimensions of the lower portion 21. In this specification, the "planar dimensions" refer to the dimensions in the direction perpendicular to the stacking direction of the base plate 20, the soldering portion 80, and the electrostatic chuck 70, that is, the above-mentioned left-right direction. 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.

[0024] A cooling path 30 is provided inside the base plate 20, for example. The cooling path 30 includes an inlet portion 31 provided at one end and a discharge portion 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 the cooling medium into the cooling path 30 from the inlet portion 31 and discharges the cooling medium from the discharge portion 32. By circulating the cooling medium in the cooling path 30 to cool the base plate 20, it is possible to cool the substrate adsorbed on the electrostatic chuck 70. In addition, as the cooling medium, water or GALDEN, for example, can be used.

[0025] A gas flow path 40 is provided inside the base plate 20, for example. The gas flow path 40 is formed to penetrate the base plate 20 in the thickness direction (the vertical direction in the figure). Specifically, the gas flow path 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 adsorbed on the electrostatic chuck 70 is introduced into the gas flow path 40. As the cooling gas, an inert gas can be used. As the inert gas, for example, helium (He) gas, argon (Ar) gas, etc. can be used.

[0026] The base plate 20 has a structure composed of, for example, a plurality of layers (here, two layers) of stacked ceramic plates 51 and 52. The base plate 20 includes the ceramic plates 51 and 52 and a brazing portion 60 that joins the ceramic plates 51 and 52. The brazing portion 60 joins the upper surfaces of the ceramic plates 52 and 51.

[0027] The ceramic plate 51 constitutes, for example, the lower portion 21 of the base plate 20. The ceramic plate 51 is formed in, for example, a disk shape. The ceramic plate 51 has, for example, an inlet portion 31, an outlet portion 32, and a recessed portion 33 constituting the cooling path 30.

[0028] 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 be open at the top of 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 communicated with the recess 33. The introduction portion 31 is formed so as to be open at the bottom 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 communicated with the recess 33. The discharge portion 32 is formed so as to be open at the bottom of the ceramic plate 51.

[0029] like Figure 2 As shown, the ceramic plate 51 has a hole 41 that constitutes the gas flow path 40. The hole 41 is formed to penetrate the ceramic plate 51 in the thickness direction. The hole 41 is formed to open at the top of the ceramic plate 51 and open at the bottom of the ceramic plate 51. The hole 41 is formed to extend linearly along the thickness direction of the ceramic plate 51, for example.

[0030] The ceramic plate 52 constitutes, for example, the upper portion 22 of the base plate 20. The ceramic plate 52 is formed in, for example, a disk shape. The planar dimensions of the ceramic plate 52 are smaller than the planar dimensions of the ceramic plate 51.

[0031] The ceramic plate 52 is provided to close the opening of the recess 33 of the ceramic plate 51. The ceramic plate 52, which closes the opening of the recess 33, the recess 33, the introduction portion 31 and the discharge portion 32 (see Figure 1 ) constitutes a cooling path 30.

[0032] The ceramic plate 52 has holes 42 and 43 that constitute the gas flow path 40. The holes 42 and 43 are formed to communicate with each other. The holes 42 and 43 are formed in cooperation to penetrate the ceramic plate 52 in the thickness direction. 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 at the bottom 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, for example, to extend linearly along the thickness direction of the ceramic plate 52.

[0033] The hole portion 43 is formed to be recessed downward from the upper surface of the ceramic plate 52 and is formed to communicate with the hole portion 42. The hole portion 43 is formed to open above the ceramic plate 52. The planar dimensions of the hole portion 43 are, for example, larger than the planar dimensions of the hole portion 42. 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 when viewed from above. Furthermore, a groove portion formed to be recessed downward from the upper surface of the ceramic plate 52 may be provided on the ceramic plate 52.

[0034] The soldering portion 60 includes a conductive pattern 61 formed on the upper surface of the ceramic plate 51 , a conductive pattern 62 formed on the lower surface of the ceramic plate 52 , and solder 63 that joins the conductive patterns 61 and 62 .

[0035] The conductive pattern 61 is provided so as to overlap with the ceramic plate 52, for example, in a plan view. The conductive pattern 61 is provided so as not to overlap with the recess 33 and the hole 41, for example, in a plan view. The conductive pattern 62 is provided so as to overlap with the conductive pattern 61, for example, in a plan view. The conductive pattern 62 is provided so as not to overlap with the recess 33 and the holes 41 and 42, for example, in a plan view.

[0036] Solder 63 joins conductive pattern 61 and conductive pattern 62. Solder 63 joins the upper surface of conductive pattern 61 and the lower surface of conductive pattern 62. Thus, conductive pattern 61 and conductive pattern 62 are joined together by brazing with solder 63. By joining conductive pattern 61 and conductive pattern 62 together, ceramic plate 51 and ceramic plate 52 are joined together. Thus, ceramic plate 52 is laminated on the upper surface of ceramic plate 51. For example, silver solder can be used as solder 63.

[0037] (Structure of Electrostatic Chuck 70)

[0038] like Figure 1 As shown, electrostatic chuck 70 includes a substrate body 71 and an electrode 72 embedded in substrate body 71. Electrostatic chuck 70 is, for example, a Johansen-Lebeck type electrostatic chuck. Alternatively, electrostatic chuck 70 may be a Coulomb force type electrostatic chuck. Electrostatic chuck 70 is a holding member that attracts and holds a substrate, serving as an object to be attracted.

[0039] The substrate body 71 is formed, for example, in a disk shape. The diameter of the substrate body 71 can be, for example, equal to or greater than the diameter of the upper portion 22 of the base plate 20. In this embodiment, the diameter of the substrate body 71 is equal to the diameter of the upper portion 22. The diameter of the substrate body 71 can be, for example, approximately 150 mm to 500 mm. The thickness of the substrate body 71 can be, for example, approximately 0.5 mm to 10 mm.

[0040] The substrate body 71 has a mounting surface 71A (here, the upper surface) on which a substrate serving as an adsorption target is mounted. The substrate body 71 is, for example, a dielectric. The substrate body 71 is, for example, a ceramic substrate.

[0041] The substrate body 71 is provided with a gas flow path 73, for example. The gas flow path 73 is formed to penetrate the substrate body 71 in the thickness direction. The gas flow path 73 is formed to open at the top of the substrate body 71 and open at the bottom of the substrate body 71. The gas flow path 73 is formed to communicate with the gas flow path 40 of the base plate 20. Figure 2 As shown, the gas flow path 73 is formed to communicate with the hole portion 43 of the ceramic plate 52. The gas flow path 73 is formed, for example, to extend linearly along the thickness direction of the substrate body 71. The planar dimensions of the gas flow path 73 are, for example, smaller than the planar dimensions of the hole portion 43. In other words, the opening area of ​​the gas flow path 73 is smaller than the opening area of ​​the hole portion 43. The gas flow path 73 is arranged so that its entirety overlaps with the hole portion 43 when viewed from above. For example, the gas flow path 73 is arranged at a position different from the hole portion 42 when viewed from above.

[0042] like Figure 1 As shown, the substrate fixing device 10 includes a gas hole 11 formed by the gas flow path 40 and the gas flow path 73. The gas hole 11 is formed by connecting the gas flow path 40 and the gas flow path 73, extending from the mounting surface 71A of the substrate body 71 to the lower surface of the base plate 20. Inert gas is introduced into the gas hole 11 via the gas flow path 40 and then exhausted from the gas hole 11 via the gas flow path 73. The inert gas exhausted from the gas flow path 73 can cool the substrate by, for example, filling the space between the lower surface of the substrate mounted on the mounting surface 71A and the mounting surface 71A.

[0043] The electrode 72 is, for example, an electrostatic electrode for adsorbing the substrate placed on the mounting surface 71A. The electrode 72 is an electrode formed in the shape of a thin film. The electrode 72 is, for example, built into a portion of the substrate body 71 that is located near the mounting surface 71A in the thickness direction. The electrode 72 is, for example, arranged on a plane parallel to the mounting surface 71A. The electrode 72 is, for example, electrically connected to an adsorption power supply provided on the outside of the substrate fixing device 10. If a predetermined voltage is applied from the adsorption power supply, an adsorption force based on electrostatics is generated between the electrode 72 and the substrate placed on the mounting surface 71A. As a result, the substrate can be adsorbed and held on the mounting surface 71A. The higher the voltage applied to the electrode 72, the stronger the adsorption and holding force of the electrostatic suction cup 70. The electrode 72 can be in a monopolar shape or a bipolar shape. As the material of the electrode 72, for example, tungsten (W) or molybdenum (Mo) can be used. In addition, although one electrode 72 is shown in each of the drawings, it actually includes a plurality of electrodes arranged on the same plane.

[0044] (Structure of the Brazing Portion 80)

[0045] like Figure 2 As shown, soldering portion 80 includes a conductive pattern 81 formed on the upper surface of base plate 20 , a conductive pattern 82 formed on the lower surface of electrostatic chuck 70 , and solder 83 that joins conductive patterns 81 and 82 .

[0046] Conductive pattern 81 is formed on the upper surface of ceramic plate 52. Conductive pattern 81 is provided so as to overlap electrostatic chuck 70, for example, when viewed from above. Conductive pattern 81 is provided so as not to overlap hole 43 or gas flow path 73, for example, when viewed from above. For example, conductive pattern 81 is formed so as to cover the entire upper surface of ceramic plate 52.

[0047] Conductive pattern 82 is formed on the lower surface of substrate body 71. Conductive pattern 82 is provided so as to overlap conductive pattern 81 in plan view, for example. Conductive pattern 82 is provided so as not to overlap hole 43 and gas flow path 73 in plan view, for example.

[0048] Solder 83 joins conductive pattern 81 and conductive pattern 82. Solder 83 joins the upper surface of conductive pattern 81 and the lower surface of conductive pattern 82. Thus, conductive pattern 81 and conductive pattern 82 are joined together by brazing with solder 83. By joining conductive pattern 81 and conductive pattern 82 together, base plate 20 and electrostatic chuck 70 are joined together. Thus, electrostatic chuck 70 is laminated on the upper surface of base plate 20. For example, silver solder can be used as solder 83.

[0049] (Structure of Protective Layer 90)

[0050] The protective layer 90 has the function of protecting the soldered portions 60 and 80 from the effects of plasma. The protective layer 90 is formed on the outer side surfaces of the base plate 20 and the outer side surfaces of the electrostatic chuck 70 so as to cover the soldered portions 60 and 80. The protective layer 90 is formed so as to cover the entire outer side surface of the soldered portion 60. In other words, the protective layer 90 is formed so as to cover the entire outer side surface of the conductive pattern 61, the entire outer side surface of the conductive pattern 62, and the entire outer side surface of the solder 63. The protective layer 90 is formed so as to cover the entire outer side surface of the soldered portion 80. In other words, the protective layer 90 is formed so as to cover the entire outer side surface of the conductive pattern 81, the entire outer side surface of the conductive pattern 82, and the entire outer side surface of the solder 83. The protective layer 90 is formed so as to cover the outer side surfaces of the soldered portions 60 and 80 throughout the entire circumference of the base plate 20. For example, the protective layer 90 is formed so as to continuously cover the soldered portion 60 and the soldered portion 80.

[0051] The protective layer 90 is formed, for example, to cover the entire outer surface of the upper portion 22 of the base plate 20. That is, the protective layer 90 is formed to cover the entire outer surface of the ceramic plate 52. The protective layer 90 is formed, for example, to cover a portion of the outer surface of the electrostatic chuck 70. The protective layer 90 is formed, for example, to cover a portion of the outer surface of the substrate body 71. In this embodiment, the protective layer 90 is formed to cover the outer surface of the lower portion of the substrate body 71, while leaving the outer surface of the upper portion of the substrate body 71 exposed.

[0052] As the material for protective layer 90, for example, a low thermal expansion ceramic material can be used. As the material for protective layer 90, for example, ceramic materials such as aluminum oxide, aluminum nitride, and yttrium oxide can be used. As the material for protective layer 90, for example, fluororesins and epoxy resins with excellent plasma resistance can also be used.

[0053] 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, and the gas flow path 73 is an example of a second gas flow path. The ceramic plate 51 is an example of a first ceramic plate, and the ceramic plate 52 is an example of a second ceramic plate. The soldering portion 60 is an example of a second soldering portion, the conductive pattern 61 is an example of a third conductive pattern, the conductive pattern 62 is an example of a fourth conductive pattern, and the solder 63 is an example of a second solder. The soldering portion 80 is an example of a first soldering portion, the conductive pattern 81 is an example of a first conductive pattern, the conductive pattern 82 is an example of a second conductive pattern, and the solder 83 is an example of a first solder.

[0054] (Method of Manufacturing Substrate Fixing Device 10)

[0055] Next, a method for manufacturing the substrate fixing device 10 will be described. For convenience of description, components that ultimately become the substrate fixing device 10 will be described with reference numerals corresponding to the components ultimately used.

[0056] First, in Figure 3 In the illustrated process, a ceramic plate 51 having a conductive pattern 61 for soldering formed on its upper surface is prepared. Separately, a ceramic plate 52 having a conductive pattern 62 for soldering formed on its lower surface and a conductive pattern 81 for soldering formed on its upper surface is prepared. Furthermore, an electrostatic chuck 70 having a substrate body 71 having a conductive pattern 82 for soldering formed on its lower surface is prepared. These two ceramic plates 51 and 52 and substrate body 71 can be manufactured, for example, using a green sheet method.

[0057] Then, in Figure 4 In the process shown in FIG. 1 , the inlet portion 31 and the outlet portion 32 (see FIG. 1 ) are formed on the ceramic plate 51. Figure 1 ) and the recess 33, and form the hole 41. The introduction portion 31, the discharge portion 32, the recess 33 and the hole 41 can be formed by, for example, laser processing or machining.

[0058] In addition, Figure 4 In the steps shown, the holes 42 and 43 are formed in the ceramic plate 52. The holes 42 and 43 can be formed by, for example, laser processing or machining.

[0059] In addition, Figure 4 In the illustrated process, the gas flow path 73 is formed on the substrate body 71. The gas flow path 73 can be formed by, for example, laser processing or machining.

[0060] Next, ceramic plate 52 is placed above ceramic plate 51 with conductive pattern 62 facing conductive pattern 61. At this point, ceramic plates 51 and 52 are aligned so that hole 42 overlaps hole 41 when viewed from above. Furthermore, substrate body 71 is placed above ceramic plate 52 with conductive pattern 82 facing conductive pattern 81. At this point, ceramic plate 52 and substrate body 71 are aligned so that gas flow path 73 overlaps hole 43 when viewed from above.

[0061] Next, in Figure 5In the process shown, the conductive pattern 61 and the conductive pattern 62 are joined by brazing using the solder 63. Thus, the ceramic plate 52 can be joined to the upper surface of the ceramic plate 51. Furthermore, the conductive pattern 81 and the conductive pattern 82 are joined by brazing using the solder 83. Thus, the substrate body 71 can be joined to the upper surface of the ceramic plate 52. Through this process, the opening of the recess 33 is closed by the ceramic plate 52. Thus, the inlet portion 31 and the outlet portion 32 (see Figure 1 ) and the recess 33, and the ceramic plate 52 that closes the opening of the recess 33 form the cooling path 30. In addition, through this process, the hole 41 of the ceramic plate 51 and the holes 42 and 43 of the ceramic plate 52 are connected to form the gas flow path 40, and the gas flow path 40 and the gas flow path 73 are connected to form the gas hole 11.

[0062] Through the above manufacturing steps, the base plate 20 including the ceramic plates 51 and 52 is formed, and the electrostatic chuck 70 is bonded to the base plate 20 .

[0063] Next, a protective layer 90 is formed on the outer side surfaces of the ceramic plate 52 and the substrate body 71 to cover the brazing portions 60 and 80. The protective layer 90 can be formed, for example, by physical vapor deposition or chemical vapor deposition. When a fluororesin or epoxy resin is used as the material for the protective layer 90, for example, the protective layer 90 can be formed by applying a liquid resin to the outer side surfaces of the ceramic plate 52 and the substrate body 71 and then curing the liquid resin.

[0064] The substrate fixing device 10 of this embodiment can be manufactured through the above-mentioned manufacturing steps.

[0065] Next, the effects of this embodiment will be described.

[0066] (1) Substrate fixing device 10 includes: a ceramic base plate 20; a ceramic electrostatic chuck 70 having a mounting surface 71A for mounting an object to be attracted; and a brazing portion 80 that joins base plate 20 and electrostatic chuck 70. Base plate 20 is made of a ceramic material having a thermal expansion coefficient of 0±5 ppm / K at room temperature. Electrostatic chuck 70 is also made of a ceramic material having a thermal expansion coefficient of 0±5 ppm / K at room temperature.

[0067] According to this structure, both the base plate 20 and the electrostatic chuck 70 are made of low thermal expansion ceramic material. Therefore, when the substrate fixing device 10 is exposed to a low temperature of about -60°C or a high temperature of about 180°C, thermal deformation such as thermal expansion and thermal contraction will hardly occur in the base plate 20 and the electrostatic chuck 70. Therefore, 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 appropriately suppress a large difference between the thermal deformation of the base plate 20 and the thermal deformation of the electrostatic chuck 70. As a result, it is possible to appropriately suppress the thermal stress caused by thermal expansion and thermal contraction from acting on the brazing portion 80 provided between the base plate 20 and the electrostatic chuck 70. Thus, it is possible to appropriately suppress the situation where the brazing portion 80 is damaged due to thermal stress. Therefore, it is possible to appropriately suppress the reduction in the in-plane uniformity of the thermal resistance of the brazing portion 80 due to the damage of the brazing portion 80. Therefore, it is possible to suppress temperature fluctuations on mounting surface 71A of electrostatic chuck 70 , and improve the temperature uniformity of mounting surface 71A of electrostatic chuck 70 .

[0068] (2) However, when the substrate fixing device 10 is in operation, the temperature of the base plate 20 and the temperature of the electrostatic chuck 70 may differ from each other. In this case, even if the base plate 20 and the electrostatic chuck 70 are made of the same ceramic material, if the thermal expansion coefficient of the ceramic material is 6 to 8 ppm / K, thermal stress is generated due to the difference in thermal expansion caused by the temperature difference.

[0069] In contrast, in the substrate fixing device 10 of this embodiment, both the base plate 20 and the electrostatic chuck 70 are made of a low-thermal-expansion ceramic material. Therefore, even when the temperatures of the base plate 20 and the electrostatic chuck 70 differ from each other, little thermal deformation occurs in the base plate 20 and the electrostatic chuck 70. Consequently, a significant difference in the amount of thermal deformation between the base plate 20 and the electrostatic chuck 70 can be appropriately suppressed. Consequently, thermal stress caused by thermal expansion and contraction can be appropriately suppressed from acting on the brazing portion 80 joining the base plate 20 and the electrostatic chuck 70.

[0070] (3) Even when the substrate fixture 10 is exposed to temperatures as low as -60°C or as high as 180°C, damage to the substrate fixture 10 (i.e., the base plate 20, the electrostatic chuck 70, and the soldered portion 80) can be suppressed. Therefore, a single substrate fixture 10 can be appropriately used over a wide temperature range.

[0071] (4) With respect to the substrate fixing device 10, it is more preferable that the base plate 20 is made of a ceramic material having a thermal expansion coefficient of 0±1 ppm / K at room temperature. In addition, it is more preferable that the electrostatic chuck 70 is made of a ceramic material having a thermal expansion coefficient of 0±1 ppm / K at room temperature. Thus, even when the temperature of the base plate 20 and the temperature of the electrostatic chuck 70 are different from each other, the generation of thermal deformation of the base plate 20 and the electrostatic chuck 70 is further suppressed. Therefore, the difference between the thermal deformation amount of the base plate 20 and the thermal deformation amount of the electrostatic chuck 70 can be more appropriately suppressed. As a result, the thermal stress caused by thermal expansion and thermal contraction acting on the soldering portion 80 that joins the base plate 20 and the electrostatic chuck 70 can be more appropriately suppressed.

[0072] (5) A protective layer 90 is formed on the outer side surfaces of the base plate 20 and the electrostatic chuck 70 to cover the soldered portions 60 and 80. This protective layer 90 protects the soldered portions 60 and 80 from the effects of plasma. This prevents degradation of the soldered portions 60 and 80 due to plasma, thereby extending the life of the substrate fixing device 10.

[0073] (6) Soldering portion 80 includes a conductive pattern 81 formed on the upper surface of base plate 20, a conductive pattern 82 formed on the lower surface of electrostatic chuck 70, and solder 83. With this structure, conductive patterns 81 and 82 are joined by soldering with solder 83, thereby joining electrostatic chuck 70 to base plate 20. The substrate fixture 10 thus formed has a structure including conductive patterns 81 and 82. Therefore, the rigidity of substrate fixture 10 can be improved compared to, for example, a case where base plate 20 and electrostatic chuck 70 are joined to each other using an adhesive.

[0074] (7) The base plate 20 is composed of a plurality of ceramic plates 51 and 52 joined to each other by brazing portions 60. In this structure, conductive patterns 61 and 62 for brazing are provided on the ceramic plates 51 and 52. Furthermore, the conductive patterns 61 and 62 are joined by brazing using solder 63, thereby joining the ceramic plate 52 to the ceramic plate 51. The base plate 20 thus formed has a structure having the conductive patterns 61 and 62. Therefore, compared to a case where the ceramic plates 51 and 52 are joined to each other using an adhesive, for example, the rigidity of the base plate 20 can be increased.

[0075] (8) The plurality of ceramic plates 51 and 52 are joined together using the brazing portion 60, and the base plate 20 and the electrostatic chuck 70 are joined together using the brazing portion 80. With this structure, the ceramic plates 51 and 52 and the substrate body 71 can be joined together using solder 63, 83, etc., which is harder than an adhesive. This improves the airtightness of the cooling paths 30 and the gas holes 11 formed in the ceramic plates 51 and 52 and the substrate body 71.

[0076] (Other embodiments)

[0077] The above embodiment can be modified and implemented as follows: The above embodiment and the following modified examples can be combined and implemented within the scope of no technical contradiction.

[0078] The structure of the substrate fixing device 10 of the above-described embodiment can be modified as appropriate.

[0079] ·For example Figure 6 As shown, the protective layer 90 can be formed to cover the entire outer side surface of the upper portion 22 of the base plate 20 and the entire outer side surface of the electrostatic chuck 70. In other words, the protective layer 90 can be formed to cover the entire outer side surface of the ceramic plate 52 and the entire outer side surface of the substrate body 71.

[0080] ·exist Figure 6 In the modified example shown, the protective layer 90 may be formed so as to cover the entire outer surface of the lower portion 21 of the base plate 20 . That is, the protective layer 90 may be formed so as to cover the entire outer surface of the ceramic plate 51 .

[0081] The protective layer 90 of the above embodiment may be omitted.

[0082] The electrostatic chuck 70 of the above-described embodiment may include an electrode other than the electrode 72. Examples of the different electrode include a heating element for heating a substrate placed on the mounting surface 71A.

[0083] A relief pattern may be provided on mounting surface 71A of electrostatic chuck 70 in the above-described embodiment.

[0084] The shape of the gas hole 11 of the substrate fixing device 10 of the above embodiment can be modified as appropriate. In addition, the gas hole 11 can be omitted.

[0085] The shape of the cooling passage 30 of the base plate 20 in the above embodiment can be modified as appropriate. In addition, the cooling passage 30 can be omitted.

[0086] In the above embodiment, the base plate 20 and the electrostatic chuck 70 are bonded to each other using the soldering portion 80 , but the present invention is not limited thereto. For example, the base plate 20 and the electrostatic chuck 70 may be bonded to each other by bonding the conductive patterns 81 and 82 to each other using a conductive adhesive.

[0087] In the above-described embodiment, the base plate 20 is bonded to the ceramic plates 51 and 52 using the brazing portion 60. However, this is not limiting. For example, the conductive patterns 61 and 62 may be bonded to each other using a conductive adhesive. Alternatively, the conductive patterns 61 and 62 may be omitted, and the ceramic plates 51 and 52 may be bonded to each other using an adhesive such as a silicone adhesive.

[0088] The number of ceramic plates 51 and 52 of the base plate 20 in the above embodiment is not particularly limited. For example, the base plate 20 may include one ceramic plate or three or more ceramic plates.

[0089] In the manufacturing method of the above embodiment, the recesses 33 and the holes 41, 42, 43 are formed on the ceramic plates 51, 52 after the green sheets are sintered. However, the present invention is not limited to this. For example, the recesses 33 and the holes 41, 42, 43 may be formed on the green sheets before they are sintered, i.e., before they are sintered.

[0090] In the manufacturing method of the above embodiment, the gas flow paths 73 are formed on the substrate body 71 after the green sheet is sintered, but the present invention is not limited thereto. For example, the gas flow paths 73 may be formed on the green sheet before sintering, that is, before sintering.

[0091] The substrate holding device 10 of the above embodiment is applied to semiconductor manufacturing equipment, such as a dry etching apparatus. Examples of dry etching apparatus include parallel plate reactive ion etching apparatuses. Furthermore, the substrate holding device 10 can also be applied to semiconductor manufacturing equipment such as plasma CVD (Chemical Vapor Deposition) apparatuses and sputtering apparatuses.

[0092] Description of the label

[0093] 10. Substrate fixing device

[0094] 11 Gas holes

[0095] 20 base plate

[0096] 21 lower part

[0097] 22 upper part

[0098] 30 Cooling circuit

[0099] 31 Introduction

[0100] 32 discharge section

[0101] 33 recess

[0102] 40 Gas flow path

[0103] 41 hole (first hole)

[0104] Holes 42 and 43 (second hole)

[0105] 51 Ceramic plate (1st ceramic plate)

[0106] 52 Ceramic plate (2nd ceramic plate)

[0107] 60 Brazing portion (second brazing portion)

[0108] 61 conductive pattern (third conductive pattern)

[0109] 62 conductive pattern (fourth conductive pattern)

[0110] 63 Solder (Second Solder)

[0111] 70 Electrostatic Chuck

[0112] 71 substrate main body

[0113] 71A mounting surface

[0114] 72 electrodes

[0115] 73 Gas flow path

[0116] 80 Brazing part (first brazing part)

[0117] 81 conductive pattern (first conductive pattern)

[0118] 82 conductive pattern (second conductive pattern)

[0119] 83 solder (first solder)

[0120] 90 protective layer

Claims

1. A substrate fixing device, wherein: The substrate fixing device comprises: a base plate made of ceramic; A ceramic electrostatic chuck having a mounting surface for mounting an object to be adsorbed; and a first soldering portion that joins the base plate and the electrostatic chuck together, The base plate is made of a ceramic material with a thermal expansion coefficient of 0±3 ppm / K at room temperature. The electrostatic chuck is made of a ceramic material having a thermal expansion coefficient of 0±3 ppm / K at room temperature.

2. The substrate fixing device according to claim 1, wherein: The base plate is made of a ceramic material with a thermal expansion coefficient of 0±1 ppm / K at room temperature. The electrostatic chuck is made of a ceramic material having a thermal expansion coefficient of 0±1 ppm / K at room temperature.

3. The substrate fixing device according to claim 1 or 2, wherein: The substrate fixing device further includes a protective layer formed on an outer side surface of the base plate and an outer side surface of the electrostatic chuck so as to cover the first soldering portion.

4. The substrate fixing device according to claim 3, wherein: The base plate has a lower portion and an upper portion stacked on an upper surface of the lower portion. The planar size of the upper portion is formed to be smaller than the planar size of the lower portion, The protective layer is formed to cover the entire outer side surface of the upper portion and the entire outer side surface of the electrostatic chuck.

5. The substrate fixing device according to claim 1 or 2, wherein: The first brazing portion includes: a first conductive pattern formed on the upper surface of the base plate; a second conductive pattern formed on the lower surface of the electrostatic chuck; and a first solder that joins the first conductive pattern and the second conductive pattern together.

6. The substrate fixing device according to claim 1 or 2, wherein: The base plate has: 1st ceramic plate; a second ceramic plate disposed on the first ceramic plate; and a second brazing portion that joins the first ceramic plate and the second ceramic plate together; The second brazing portion includes: a third conductive pattern formed on the upper surface of the first ceramic plate; a fourth conductive pattern formed on the lower surface of the second ceramic plate; and The second solder joins the third conductive pattern and the fourth conductive pattern together.

7. The substrate fixing device according to claim 6, wherein: The base plate has a cooling path formed by a recessed portion recessed downward from the upper surface of the first ceramic plate and the second ceramic plate provided to close an opening of the recessed portion. The third conductive pattern is arranged to overlap with the second ceramic plate in a plan view. The fourth conductive pattern is provided so as to overlap with the third conductive pattern and so as not to overlap with the recessed portion in a plan view.

8. The substrate fixing device according to claim 6, wherein: The base plate has a first gas flow path penetrating the base plate in a thickness direction. The electrostatic chuck has a second gas flow path communicating with the first gas flow path. The first gas flow path includes: a first hole portion penetrating the first ceramic plate in the thickness direction; and a second hole portion penetrating the second ceramic plate in the thickness direction and communicating with the first hole portion. The second gas flow path is formed to penetrate the electrostatic chuck in a thickness direction and communicate with the second hole.

9. The substrate fixing device according to claim 1 or 2, wherein: The substrate fixing device further includes an electrode built into the electrostatic chuck.

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

Images