substrate fixing device

Abstract

To provide a substrate fixing device which can prevent removal of an insulation layer.SOLUTION: A substrate fixing device has: a base plate; a heating part provided above the base plate via an adhesive layer; and an electrostatic chuck, provided on the heating part, which attracts and holds an object to be attracted. The heating part includes: a first insulation layer whose one surface makes contact with the electrostatic chuck; a heating element disposed on the other surface of the first insulation layer; and a second insulation layer which is laminated on the other surface of the first insulation layer so as to cover the heating element. The substrate fixing device is provided with a through-hole which penetrates the base plate, the adhesive layer, and the second insulation layer so as to expose a portion of the heating element. The glass transition temperature of the second insulation layer is higher than that of the first insulation layer.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Conventionally, a film forming apparatus (for example, a CVD apparatus, a PVD apparatus, etc.) and a plasma etching apparatus used when manufacturing semiconductor devices such as ICs and LSIs have a stage for accurately holding a wafer in a vacuum processing chamber. As such a stage, for example, a substrate fixing device that adsorbs and holds a wafer, which is an object to be adsorbed, by an electrostatic chuck mounted on a base plate has been proposed. The substrate fixing device includes, for example, a heating element for adjusting the temperature of the wafer and an insulating layer that covers the heating element (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the insulating layer covering the heating element may be exposed to a high temperature of about 300°C, and in that case, the insulating layer may deteriorate and peel off.

[0005] The present invention has been made in view of the above points, and an object thereof is to provide a substrate fixing device capable of suppressing peeling of the insulating layer.

Means for Solving the Problems

[0006] The substrate fixing device comprises a base plate, a heating element provided on the base plate via an adhesive layer, and an electrostatic chuck provided on the heating element for adsorbing and holding an object to be adsorbed. The heating element includes a first insulating layer with one surface in contact with the electrostatic chuck, a heating element disposed on the other surface of the first insulating layer, and a second insulating layer laminated on the other surface of the first insulating layer and covering the heating element. Through holes are provided that penetrate the base plate, the adhesive layer, and the second insulating layer, exposing a portion of the heating element. The material of the second insulating layer is a polyimide resin. The glass transition temperature of the second insulating layer is higher than that of the first insulating layer. [Effects of the Invention]

[0007] According to the disclosed technology, a substrate fixing device capable of suppressing peeling of the insulating layer can be provided. [Brief explanation of the drawing]

[0008] [Figure 1] This is a simplified cross-sectional view illustrating a substrate fixing device according to the first embodiment. [Figure 2] This is a diagram (part 1) illustrating the manufacturing process of a substrate fixing device according to the first embodiment. [Figure 3] This is a diagram (part 2) illustrating the manufacturing process of a substrate fixing device according to the first embodiment. [Figure 4] This is a simplified cross-sectional view illustrating a substrate fixing device according to the second embodiment. [Figure 5] This is a diagram (part 1) illustrating the manufacturing process of a substrate fixing device according to the second embodiment. [Figure 6] This is a diagram (part 2) illustrating the manufacturing process of a substrate fixing device according to the second embodiment. [Modes for carrying out the invention]

[0009] The embodiments for carrying out the invention will be described below with reference to the drawings. In each drawing, the same reference numerals are used for identical components, and redundant explanations may be omitted.

[0010] <First Embodiment> [Structure of the substrate fixing device] Figure 1 is a simplified cross-sectional view illustrating a substrate fixing device according to the first embodiment. Referring to Figure 1, the substrate fixing device 1 has as its main components a base plate 10, an adhesive layer 20, a heating element 30, and an electrostatic chuck 40.

[0011] The base plate 10 is a component for mounting the heat-generating unit 30 and the electrostatic chuck 40. The thickness of the base plate 10 can be, for example, about 20 to 50 mm. The base plate 10 can be made of, for example, aluminum and can also be used as an electrode for controlling the plasma. By supplying a predetermined high-frequency power to the base plate 10, the energy for causing ions in the generated plasma state to collide with the wafer adsorbed on the electrostatic chuck 40 can be controlled, and the etching process can be performed effectively.

[0012] A refrigerant flow path 15 may be provided inside the base plate 10. The refrigerant flow path 15 has a refrigerant inlet 15a at one end and a refrigerant outlet 15b at the other end. The refrigerant flow path 15 is connected to a refrigerant control device (not shown) provided outside the substrate fixing device 1. The refrigerant control device (not shown) introduces a refrigerant (for example, cooling water or galden, etc.) into the refrigerant flow path 15 from the refrigerant inlet 15a and discharges the refrigerant from the refrigerant outlet 15b. By circulating the refrigerant in the refrigerant flow path 15 and cooling the base plate 10, the wafer adsorbed on the electrostatic chuck 40 can be cooled.

[0013] A gas supply unit may be provided inside the base plate 10 to supply gas for cooling the wafer held by the electrostatic chuck 40. The gas supply unit is, for example, a hole formed inside the base plate 10. By introducing an inert gas (for example, He or Ar) from outside the substrate fixing device 1 into the gas supply unit, the wafer held by the electrostatic chuck 40 can be cooled.

[0014] The heating element 30 is provided on the base plate 10 via an adhesive layer 20. The adhesive layer 20 can be a two-layer structure, for example, a first layer 21 and a second layer 22. For the first layer 21 and the second layer 22, for example, a silicone-based adhesive can be used. The thickness of each of the first layer 21 and the second layer 22 can be, for example, about 1 mm. The thermal conductivity of the first layer 21 and the second layer 22 is preferably 2 W / mK or higher. The adhesive layer 20 may be formed from a single layer, but by using a two-layer structure combining an adhesive with high thermal conductivity and an adhesive with low elastic modulus, the effect of reducing stress caused by the difference in thermal expansion with the aluminum base plate can be obtained.

[0015] The heating element 30 comprises a first insulating layer 31, a heating element 32, and a second insulating layer 33. The upper surface of the first insulating layer 31 is in contact with the lower surface of the base body 41 of the electrostatic chuck 40. The heating element 32 is positioned on the lower surface of the first insulating layer 31 and is bonded to the lower surface of the base body 41 by the first insulating layer 31. The second insulating layer 33 is laminated on the lower surface of the first insulating layer 31 and covers the lower surface and sides of the heating element 32. The substrate fixing device 1 is provided with a plurality of through holes 10x that penetrate the base plate 10, the adhesive layer 20, and the second insulating layer 33 of the heating element 30, exposing a portion of the lower surface of the heating element 32 of the heating element 30. Each through hole 10x can be used as a passage for wire when soldering wire to the heating element 32 exposed within the through hole 10x.

[0016] As the first insulating layer 31, it is preferable to use an insulating resin having excellent adhesiveness between the heating element 32 and the substrate 41. Specifically, for example, an epoxy resin can be used as the material of the first insulating layer 31. Further, the thermal conductivity of the first insulating layer 31 is preferably 3 W / mK or more. By including fillers such as alumina or aluminum nitride in the first insulating layer 31, the thermal conductivity of the first insulating layer 31 can be improved. The glass transition temperature (Tg) of the first insulating layer 31 can be, for example, about 150 to 200°C. Also, the thickness of the first insulating layer 31 is preferably, for example, about 60 to 100 μm, and the thickness variation of the first insulating layer 31 is preferably ±10% or less.

[0017] As the heating element 32, it is preferable to use a rolled alloy. By using a rolled alloy, it becomes possible to reduce the variation in the thickness of the heating element 32 and improve the heat generation distribution. Note that the heating element 32 does not necessarily have to be built in the central portion in the thickness direction of the heating portion 30, and may be unevenly distributed closer to the base plate 10 side or the electrostatic chuck 40 side than the central portion in the thickness direction of the heating portion 30 according to the required specifications.

[0018] The specific resistance of the heating element 32 is preferably 10 to 70 μΩ·cm, and more preferably 10 to 50 μΩ·cm. In a conventional substrate fixing device, since a NiCr-based heating element having a specific resistance of about 100 μΩ·cm was used, when a wiring design of 20 to 50 Ω was made, the wiring width was 1 to 2 mm and the thickness was about 50 μm, making it difficult to refine the pattern of the heating element. By setting the specific resistance of the heating element 32 to 1 to 70 μΩ·cm, which is lower than the specific resistance of the NiCr-based heating element, when the same wiring design of 20 to 50 Ω as above is made, it becomes possible to refine the pattern of the heating element 32 more than before. Note that if the specific resistance is less than 10 μΩ·cm, the heat generation performance deteriorates, which is not preferable.

[0019] Specific rolling alloys suitable for use in the heating element 32 include, for example, CN49 (constantan) (an alloy of Cu / Ni / Mn / Fe), zelanin (an alloy of Cu / Mn / Sn), manganin (an alloy of Cu / Mn / Ni), etc. The resistivity of CN49 (constantan) is about 50 μΩ·cm, the resistivity of zelanin is about 29 μΩ·cm, and the resistivity of manganin is about 44 μΩ·cm. Considering the wiring formation property by etching, the thickness of the heating element 32 is preferably 60 μm or less. <0000'094><0000'095><0000'096>In addition, in order to improve the adhesion between the heating element 32 and the first insulating layer 31 at high temperatures, it is preferable that at least one surface (one or both of the upper and lower surfaces) of the heating element 32 is roughened. Of course, both the upper and lower surfaces of the heating element 32 may be roughened. In this case, different roughening methods may be used for the upper and lower surfaces of the heating element 32. The roughening method is not particularly limited, and examples thereof include a method by etching, a method using a coupling agent-based surface modification technique, a method using dot processing with a UV-YAG laser having a wavelength of 355 nm or less, etc. <0000'097><0000'098><0000'099>As the second insulating layer 33, it is preferable to use an insulating resin with excellent heat resistance. This is because the temperature conditions tend to shift to the high-temperature side when the substrate fixing device 1 is used, and the temperature when soldering a wire to the heating element 32 through the through-hole 10x may reach 300°C or higher. Specifically, as the material of the second insulating layer 33, for example, a polyimide-based resin or a silicone-based resin can be used. The glass transition temperature of the second insulating layer 33 is higher than that of the first insulating layer 31. The glass transition temperature of the second insulating layer 33 is preferably 300°C or higher. If the glass transition temperature of the second insulating layer 33 is 300°C or higher, the substrate fixing device 1 can be used in a high-temperature environment of 300°C or lower and can also withstand the temperature when soldering a wire to the heating element 32. Therefore, in the substrate fixing device 1, it is possible to suppress the deterioration of the second insulating layer 33 due to high temperature and the peeling from the first insulating layer 31. <0000'100><0000'101><0000'102>The reason why the glass transition temperature of the first insulating layer 31 may be lower than that of the second insulating layer 33 is that the first insulating layer 31 is not directly exposed to high temperatures of around 300°C. Therefore, it is preferable to select the material of the first insulating layer 31 prioritizing adhesion to the substrate 41 over heat resistance. Furthermore, in order to provide a stress relaxation function, it is preferable to select a material for the first insulating layer 31 that has a lower elastic modulus than that of the second insulating layer 33.

[0023] The thermal conductivity of the second insulating layer 33 is preferably 3 W / mK or higher. The thermal conductivity of the second insulating layer 33 can be improved by including fillers such as alumina or aluminum nitride in the second insulating layer 33. Furthermore, the thickness of the second insulating layer 33 is preferably greater than that of the first insulating layer 31 from the viewpoint of improving the embedding of the heating element 32. The thickness of the second insulating layer 33 is preferably about 100 to 200 μm, and the thickness variation of the second insulating layer 33 is preferably ±10% or less.

[0024] The electrostatic chuck 40 is provided on the heat-generating section 30. The electrostatic chuck 40 is the part that adsorbs and holds the wafer, which is the object to be adsorbed. The planar shape of the electrostatic chuck 40 is, for example, circular. The diameter of the wafer, which is the object to be adsorbed by the electrostatic chuck 40, is, for example, 8, 12, or 18 inches. Note that "planar view" refers to viewing the object from the direction normal to the upper surface of the base body 41, and "planar shape" refers to the shape of the object when viewed from the direction normal to the upper surface of the base body 41.

[0025] The electrostatic chuck 40 is provided on the heating element 30. The electrostatic chuck 40 has a base 41 and an electrostatic electrode 42. The electrostatic chuck 40 is, for example, a Johnsen-Lahbeck type electrostatic chuck. However, the electrostatic chuck 40 may be a Coulomb force type electrostatic chuck.

[0026] The substrate 41 is a dielectric material, and for example, ceramics such as aluminum oxide (Al2O3) and aluminum nitride (AlN) can be used as the substrate 41. The thickness of the substrate 41 can be, for example, about 1 to 10 mm, and the relative permittivity (1 kHz) of the substrate 41 can be, for example, about 9 to 10. The electrostatic chuck 40 and the first insulating layer 31 of the heating element 30 are directly joined. By directly joining the heating element 30 and the electrostatic chuck 40 without using an adhesive, the heat resistance temperature of the substrate fixing device 1 can be improved. The heat resistance temperature of a conventional substrate fixing device in which the heating element 30 and the electrostatic chuck 40 are joined with an adhesive is about 150°C, but the heat resistance temperature of the substrate fixing device 1 can be about 200°C.

[0027] The electrostatic electrode 42 is a thin-film electrode and is embedded in the substrate 41. The electrostatic electrode 42 is connected to a power supply located outside the substrate fixing device 1, and when a predetermined voltage is applied, an electrostatic attraction force is generated between it and the wafer, allowing the wafer to be attracted and held on the electrostatic chuck 40. The attraction force becomes stronger as the voltage applied to the electrostatic electrode 42 increases. The electrostatic electrode 42 may be unipolar or bipolar. For example, tungsten, molybdenum, etc., can be used as the material for the electrostatic electrode 42.

[0028] [Manufacturing method for substrate fixing device] Figures 2 and 3 illustrate the manufacturing process of the substrate fixing device according to the first embodiment. The manufacturing process of the substrate fixing device 1 will be explained, focusing on the process of forming the heat-generating section 30, with reference to Figures 2 and 3. Note that Figures 2(a) to 3(b) are drawn inverted vertically compared to Figure 1.

[0029] First, in the process shown in Figure 2(a), an electrostatic chuck 40 is manufactured by a known manufacturing method that includes a step of processing vias into a green sheet, a step of filling the vias with conductive paste, a step of forming a pattern that will become an electrostatic electrode, a step of laminating and firing other green sheets, and a step of flattening the surface, thereby creating an electrostatic chuck 40 with an electrostatic electrode 42 embedded in a substrate 41. In order to improve adhesion with the insulating resin film 311, the surface of the electrostatic chuck 40 to which the insulating resin film 311 is laminated may be roughened by blasting or the like.

[0030] Next, in the process shown in Figure 2(b), the insulating resin film 311 is directly laminated onto the electrostatic chuck 40. Laminating the insulating resin film 311 in a vacuum is preferable because it suppresses the inclusion of voids. The insulating resin film 311 is left in a semi-cured state (B-stage) without being fully cured. Due to the adhesive force of the semi-cured insulating resin film 311, the insulating resin film 311 is temporarily fixed onto the electrostatic chuck 40. For example, epoxy resin can be used as the material for the insulating resin film 311.

[0031] Next, in the step shown in Figure 2(c), the metal foil 321 is placed on the insulating resin film 311. As the material for the metal foil 321, the rolled alloy exemplified as the material for the heating element 32 can be used. The thickness of the metal foil 321 is preferably 60 μm or less, taking into consideration the ease of wiring formation by etching. The metal foil 321 is temporarily fixed on the insulating resin film 311 by the adhesive force of the insulating resin film 311, which is in a semi-cured state.

[0032] Furthermore, it is preferable to roughen at least one surface (one or both of the upper and lower surfaces) of the metal foil 321 before placing it on the insulating resin film 311. Of course, both the upper and lower surfaces of the metal foil 321 may be roughened. In this case, different roughening methods may be used for the upper and lower surfaces of the metal foil 321. The roughening method is not particularly limited, but examples include etching, surface modification techniques using coupling agents, and dot processing using a UV-YAG laser with a wavelength of 355 nm or less.

[0033] Furthermore, the dot processing method allows for selective roughening of the necessary areas of the metal foil 321. Therefore, with the dot processing method, it is not necessary to roughen the entire area of ​​the metal foil 321; it is sufficient to roughen only the area to be left as the heating element 32 (i.e., it is not necessary to roughen the area that will be removed by etching).

[0034] Next, in the process shown in Figure 2(d), the metal foil 321 is patterned to form the heating element 32. Specifically, for example, a resist is formed over the entire surface of the metal foil 321, the resist is exposed and developed to form a resist pattern that covers only the portion to be left as the heating element 32. Next, the parts of the metal foil 321 not covered by the resist pattern are removed by etching. As the etching solution to remove the metal foil 321, for example, a cupric chloride etching solution or a ferric chloride etching solution can be used.

[0035] Subsequently, the resist pattern is peeled off with a stripping solution, thereby forming a heating element 32 at a predetermined position on the insulating resin film 311 (photolithography method). By forming the heating element 32 using photolithography, it is possible to reduce variations in the widthwise dimensions of the heating element 32, thereby improving the heat distribution. The cross-sectional shape of the heating element 32 formed by etching can be, for example, approximately trapezoidal. In this case, the difference in wiring width between the surface in contact with the insulating resin film 311 and the opposite surface can be, for example, about 10 to 50 μm. By making the cross-sectional shape of the heating element 32 a simple approximately trapezoidal shape, the heat distribution can be improved.

[0036] Next, in the process shown in Figure 3(a), an insulating resin film 331 covering the heating element 32 is laminated onto the insulating resin film 311. Laminating the insulating resin film 331 in a vacuum is preferable because it suppresses the inclusion of voids. As the material for the insulating resin film 331, for example, a polyimide resin or a silicone resin can be used. From the viewpoint of improving the embedding of the heating element 32, the thickness of the insulating resin film 331 is preferably greater than that of the insulating resin film 311.

[0037] Next, in the step shown in Figure 3(b), the insulating resin films 311 and 331 are pressed toward the electrostatic chuck 40 while being heated to a temperature above the curing temperature to cure them. This forms a heating element 30 in which the heating element 32 is surrounded by a first insulating layer 31 and a second insulating layer 33, and the first insulating layer 31 of the heating element 30 is directly joined to the electrostatic chuck 40. Considering the stress when it returns to room temperature, it is preferable that the heating temperature of the insulating resin films 311 and 331 be 200°C or lower.

[0038] Furthermore, by pressing the insulating resin films 311 and 331 toward the electrostatic chuck 40 while heating and curing them, the unevenness of the surface of the second insulating layer 33 that is in contact with the adhesive layer 20, which is affected by the presence or absence of the heating element 32, can be reduced and flattened. It is preferable that the unevenness of the surface of the second insulating layer 33 that is in contact with the adhesive layer 20 be 7 μm or less. By making the unevenness of the surface of the second insulating layer 33 that is in contact with the adhesive layer 20 7 μm or less, it is possible to prevent air bubbles from being trapped between the second insulating layer 33 and the adhesive layer 20 (second layer 22) in the next step. In other words, it is possible to prevent a decrease in the adhesion between the second insulating layer 33 and the adhesive layer 20 (second layer 22).

[0039] Next, in the process shown in Figure 3(c), a base plate 10 with a refrigerant flow path 15 and the like formed in advance is prepared, and the first layer 21 and the second layer 22 are sequentially laminated on the base plate 10 to form an adhesive layer 20 (uncured). Then, the structure shown in Figure 3(b) is inverted and placed on the base plate 10 via the adhesive layer 20, and the adhesive layer 20 is cured. Furthermore, multiple through holes 10x are formed that penetrate the base plate 10, the adhesive layer 20, and the second insulating layer 33 of the heating element 30, exposing a part of the lower surface of the heating element 32 of the heating element 30. As a result, a substrate fixing device 1 is completed in which the heating element 30 and the electrostatic chuck 40 are sequentially laminated on the base plate 10 via the adhesive layer 20.

[0040] As described above, in the substrate fixing device 1 according to the first embodiment, the insulating layer of the heating element 30 has a laminated structure consisting of a first insulating layer 31 with excellent adhesion and a second insulating layer 33 with excellent heat resistance. By making the second insulating layer 33, which is the part that is directly exposed to heat of about 300°C through the through hole 10x during soldering, from an insulating resin with high heat resistance, it is possible to suppress the deterioration of the second insulating layer 33 due to high temperatures and peeling off from the first insulating layer 31.

[0041] <Second Embodiment> In the second embodiment, an example is shown in which a heat transfer sheet is incorporated into the heat-generating section. In the second embodiment, descriptions of components that are the same as those described in the previously described embodiments may be omitted.

[0042] [Structure of the substrate fixing device] Figure 4 is a simplified cross-sectional view illustrating a substrate fixing device according to the second embodiment. In Figure 4, the mutually orthogonal directions included in the plane parallel to the upper surface of the base plate 10 are defined as the X and Y directions, and the direction perpendicular to the X and Y directions (the thickness direction of the substrate fixing device 2) is defined as the Z direction.

[0043] Referring to Figure 4, the substrate fixing device 2 differs from the substrate fixing device 1 (see Figure 1) in that the heating element 30 has been replaced with a heating element 30A.

[0044] In the heating section 30A of the substrate fixing device 2, the first insulating layer 31 incorporates a heat transfer sheet 34, and the second insulating layer 33 incorporates a heat transfer sheet 35. The heat transfer sheets 34 and 35 are arranged substantially parallel to the XY plane so as to sandwich the heating element 32 from above and below with a predetermined gap between them. The gap between the heat transfer sheet 34 and the heating element 32 is filled with the first insulating layer 31, and the gap between the heat transfer sheet 35 and the heating element 32 is filled with the second insulating layer 33.

[0045] The heat transfer sheets 34 and 35 are not particularly limited as long as they are made of a material that uniformly diffuses the heat generated by the heat-generating part 30A (mitigating the uneven heat generation state). For example, a graphite sheet with a thermal conductivity in the XY direction : thermal conductivity in the Z direction = 100 or more : 1 can be used. For example, the thermal conductivity in the XY direction can be 300 W / mK or more, and the thermal conductivity in the Z direction can be 3 W / mK. The thickness of the single layer graphite sheet can be, for example, about 40 to 50 μm. Instead of graphite sheets, carbon sheets such as graphene sheets may be used as heat transfer sheets 34 and 35.

[0046] Note that only one of the heat transfer sheets 34 and 35 may be provided. That is, in the heat-generating section 30A, a heat transfer sheet may be incorporated into at least one of the first insulating layer 31 and the second insulating layer 33.

[0047] [Manufacturing method for substrate fixing device] Figures 5 and 6 illustrate the manufacturing process of the substrate fixing device according to the second embodiment. The manufacturing process of the substrate fixing device 2 will be explained with reference to Figures 5 and 6, focusing on the process of forming the heat-generating section 30A. Note that Figures 5(a) to 6(a) are drawn inverted vertically compared to Figure 4.

[0048] First, in the process shown in Figure 5(a), an electrostatic chuck 40 is fabricated in the same manner as in Figure 2(a), and then an insulating resin film 311, a heat transfer sheet 34, and an insulating resin film 312 are sequentially laminated onto the electrostatic chuck 40. The insulating resin films 311 and 312 are left in a semi-cured state (B-stage) without being fully cured. Due to the adhesive strength of the semi-cured insulating resin film 311, the insulating resin film 311 is temporarily fixed onto the electrostatic chuck 40. For example, epoxy resin can be used as the material for the insulating resin films 311 and 312.

[0049] Next, in the process shown in Figure 5(b), the metal foil 321 is placed on the insulating resin film 312. The metal foil 321 is temporarily fixed to the insulating resin film 312 by the adhesive force of the semi-cured insulating resin film 312. If necessary, the metal foil 321 may be subjected to surface treatment such as roughening before being placed on the insulating resin film 312.

[0050] Next, in the process shown in Figure 5(c), the metal foil 321 is patterned in the same manner as in the process shown in Figure 2(d) to form the heating element 32.

[0051] Next, in the process shown in Figure 5(d), an insulating resin film 331 covering the heating element 32, a heat transfer sheet 35, and an insulating resin film 332 are sequentially laminated onto the insulating resin film 312. For example, polyimide resins or silicone resins can be used as materials for the insulating resin films 331 and 332.

[0052] Next, in the process shown in Figure 6(a), the insulating resin films 311, 312, 331, and 332 are pressed toward the electrostatic chuck 40 while being heated to a temperature above the curing temperature to cure them. This forms a heating section 30A in which the heating element 32 and the heat transfer sheets 34 and 35 are covered with the first insulating layer 31 and the second insulating layer 33, and the first insulating layer 31 of the heating section 30A is directly joined to the electrostatic chuck 40. Considering the stress when it returns to room temperature, it is preferable that the heating temperature of the insulating resin films 311, 312, 331, and 332 be 200°C or lower.

[0053] Next, in the process shown in Figure 6(b), a base plate 10 with a refrigerant flow path 15 and the like formed in advance is prepared, and the first layer 21 and the second layer 22 are sequentially laminated on the base plate 10 to form an adhesive layer 20 (uncured). Then, the structure shown in Figure 6(a) is inverted and placed on the base plate 10 via the adhesive layer 20, and the adhesive layer 20 is cured. Furthermore, multiple through holes 10x are formed that penetrate the base plate 10, the adhesive layer 20, and the second insulating layer 33 and heat transfer sheet 35 of the heating element 30, exposing a part of the lower surface of the heating element 32 of the heating element 30. As a result, the substrate fixing device 2 is completed, in which the heating element 30A and the electrostatic chuck 40 are sequentially laminated on the base plate 10 via the adhesive layer 20.

[0054] As described above, in the substrate fixing device 2 according to the second embodiment, heat transfer sheets 34 and 35 with high thermal diffusivity in the planar direction (XY direction) are incorporated into the heat-generating section 30A. This improves thermal diffusivity in the planar direction (XY direction), reduces the influence of variations in the cross-sectional area of ​​the heat-generating element 32, and improves uniform heat distribution.

[0055] Furthermore, a laminate of multiple graphite sheets may be used as the heat transfer sheets 34 and 35, respectively. For example, a laminate of graphite sheets can be formed by laminating several to tens of layers of graphite sheets using a vacuum hot press or the like, via a resin that has impregnation properties and does not hinder thermal conductivity in the vertical and horizontal directions (e.g., bismaleimidotriazine resin). The laminate of graphite sheets can achieve, for example, a thermal conductivity of 1500 W / mK or more in the XY direction and a thermal conductivity of 8 W / mK in the Z direction, thus significantly improving the effect of promoting heat diffusion compared to using a single layer of graphite sheet.

[0056] Although preferred embodiments have been described in detail above, the invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims.

[0057] For example, in addition to semiconductor wafers (such as silicon wafers), other objects that can be adsorbed by the substrate fixing device according to the present invention include glass substrates used in the manufacturing process of liquid crystal panels and the like. [Explanation of Symbols]

[0058] 1, 2 Board fixing device 10 base plate 10x through holes 15 Refrigerant flow path 15a Refrigerant inlet 15b Refrigerant discharge part 20 Adhesive layer 21 1st layer 22 2nd layer 30, 30A heating element 31. First insulating layer 32 Heating element 33 Second insulating layer 34, 35 Heat transfer sheets 40 Electrostatic Chuck 41 Base 42 Electrostatic electrodes 50 sealing member 311, 312, 331, 332 Insulating resin film

Claims

1. base plate and A heating element provided on the base plate via an adhesive layer, The aforementioned heating element is provided with an electrostatic chuck for adsorbing and holding an object to be adsorbed, The aforementioned heating element is A first insulating layer, one side of which is in contact with the electrostatic chuck, A heating element disposed on the other side of the first insulating layer, The first insulating layer is laminated on the other side of the first insulating layer and covers the heating element, and includes a second insulating layer, A through-hole is provided that penetrates the base plate, the adhesive layer, and the second insulating layer, exposing a portion of the heating element. The material of the second insulating layer is a polyimide resin. A substrate fixing device wherein the glass transition temperature of the second insulating layer is higher than the glass transition temperature of the first insulating layer.

2. The substrate fixing apparatus according to claim 1, wherein the glass transition temperature of the second insulating layer is 300°C or higher.

3. The substrate fixing device according to claim 1, wherein the material of the first insulating layer is an epoxy resin.

4. The substrate fixing device according to claim 1, wherein the thickness of the second insulating layer is greater than the thickness of the first insulating layer.

5. A substrate fixing device according to any one of claims 1 to 4, wherein a heat transfer sheet is incorporated in at least one of the first insulating layer and the second insulating layer.

6. The substrate fixing device according to claim 5, wherein the heat transfer sheet is a graphite sheet.

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