Substrate holder

Abstract

To provide a substrate holder excellent in thermal uniformity.SOLUTION: A placing plate having an upper surface on which a substrate is placed, a heater, and a support plate in this order, the heater including a first insulating sheet, a second insulating sheet, and a heater substrate disposed between the first insulating sheet and the second insulating sheet, the heater substrate having a structure in which a heat generating circuit is sandwiched between insulating films, A thickness of each of the first insulating sheet and the second insulating sheet is larger than a half of a thickness of the heating circuit, and a hardness of each of the first insulating sheet and the second insulating sheet is smaller than a hardness of the insulating film.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a substrate holder. [Background technology]

[0002] Patent Document 1 discloses a wafer heating device that includes a mounting plate having an upper surface on which a wafer is placed and a heater that heats the mounting plate. The heater includes a base material made of an insulating material and a circuit pattern formed by a heating element. The heater has a structure in which the circuit pattern of the heating element is sandwiched between base materials made of, for example, two polyimide sheets. The circuit pattern is formed, for example, by etching a stainless steel foil that serves as the heating element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-169005 Summary of the Invention [Problem to be solved by the invention]

[0004] When a heating object such as a semiconductor substrate is heated by a heater, uniform heating is required.

[0005] Generally, a substrate holder comprises a mounting plate, a heater, and a support plate. The substrate holder heats the mounting plate with the heater, thereby heating an object placed on the upper surface of the mounting plate. A heater, which has a structure in which a heat-generating circuit formed from metal foil is sandwiched between polyimide sheets, has different thicknesses in different parts. The thickness of the heater in the part where the heating circuit wiring is present is the combined thickness of the metal foil and the polyimide sheet. The thickness of the heater in the part where the heating circuit wiring is not present is the thickness of the polyimide sheet alone. In other words, the part without wiring is thinner than the part with wiring. As a result, recesses are formed on both sides of the heater. If there is a recess on the top surface of the heater, the heater and the mounting plate will not be in close contact, and a gap will form in the recess. This gap prevents the heat from the heater from being transferred evenly to the mounting plate, making it difficult to achieve a uniform temperature distribution on the upper surface of the mounting plate.

[0006] An object of the present disclosure is to provide a substrate holder with excellent thermal uniformity. [Means for solving the problem]

[0007] The substrate holder of the present disclosure comprises, in this order, a mounting plate having an upper surface on which a substrate is placed, a heater, and a support plate. The heater has a first insulating sheet, a second insulating sheet, and a heater substrate disposed between the first insulating sheet and the second insulating sheet. The heater substrate has a structure in which a heating circuit is sandwiched between insulating films. The thickness of each of the first insulating sheet and the second insulating sheet is greater than half the thickness of the heating circuit. The hardness of each of the first insulating sheet and the second insulating sheet is less than the hardness of the insulating film. [Effects of the Invention]

[0008] The substrate holder of the present disclosure has excellent thermal uniformity. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view of a substrate holder according to the first embodiment. [Figure 2]FIG. 2 is a schematic cross-sectional view showing an enlarged portion of a heater provided in the substrate holder according to the first embodiment. [Figure 3] FIG. 3 is a schematic exploded view of the heater shown in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view of a substrate holder according to the second embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view of Model No. 1 used in the simulation of Test Example 1. [Figure 6] FIG. 6 is a schematic cross-sectional view of Model No. 2 used in the simulation of Test Example 1. [Figure 7] FIG. 7 is a diagram showing measurement points in the temperature analysis by simulation in Test Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0011] (1) The substrate holder of the present disclosure comprises, in this order, a mounting plate having an upper surface on which a substrate is placed, a heater, and a support plate. The heater has a first insulating sheet, a second insulating sheet, and a heater substrate disposed between the first insulating sheet and the second insulating sheet. The heater substrate has a structure in which a heating circuit is sandwiched between insulating films. The thickness of each of the first insulating sheet and the second insulating sheet is greater than half the thickness of the heating circuit. The hardness of each of the first insulating sheet and the second insulating sheet is less than the hardness of the insulating film.

[0012] Even if there are recesses on both sides of the heater substrate, the first and second insulating sheets deform to fit into the recesses, making it easy for the first and second insulating sheets to adhere to the heater substrate. Because voids are unlikely to form in the recesses, heat transfer from the heater substrate to the first and second insulating sheets is less likely to be impeded. Heat generated in the heat generating circuit is easily transferred evenly to the mounting plate, making it easy to achieve a uniform temperature distribution on the upper surface of the mounting plate. Therefore, the substrate holder of the present disclosure can heat the substrate evenly, resulting in excellent thermal uniformity.

[0013] (2) In the substrate holder of (1) above, the material of each of the first insulating sheet and the second insulating sheet may be a silicone resin filled with a filler.

[0014] The first and second insulating sheets, formed from silicone resin filled with filler, have excellent heat resistance, elasticity, and thermal conductivity. The heat resistance of the first and second insulating sheets makes them less susceptible to damage from heat generated in the heat-generating circuit. The elasticity of the first and second insulating sheets makes them more likely to deform to fit into recesses formed on both sides of the heater substrate. The first and second insulating sheets containing filler have higher thermal conductivity than insulating sheets without filler, making them more likely to conduct heat generated in the heat-generating circuit.

[0015] (3) In the substrate holder of (1) or (2) above, the insulating film may be made of polyimide.

[0016] Insulating films made of polyimide have excellent heat resistance and high tensile strength. The heat resistance of the insulating film makes it less likely to be damaged by the heat generated by the heat-generating circuit. Furthermore, the high tensile strength of the insulating film makes it possible to restrict the elongation of the heat-generating circuit due to thermal expansion. Therefore, displacement of the heat-generating circuit due to thermal expansion is less likely to occur.

[0017] (4) In the substrate holder of any one of (1) to (3) above, the hardness of each of the first insulating sheet and the second insulating sheet may be 10 or more and 90 or less in durometer A.

[0018] The first insulating sheet and the second insulating sheet are easily deformed so as to fit into the recessed portion of the heater substrate.

[0019] (5) In the substrate holder of any one of (1) to (4) above, the thickness of each of the first insulating sheet and the second insulating sheet may be equal to or greater than the thickness of the heat generating circuit.

[0020] The first insulating sheet and the second insulating sheet are easily deformed to fit into the recesses in the heater substrate, and recesses are less likely to form on the surfaces of the first insulating sheet and the second insulating sheet.

[0021] (6) In the substrate holder of any one of (1) to (5) above, the first insulating sheet and the second insulating sheet may each have a thermal conductivity of 3.0 W / m·K or higher.

[0022] Heat is easily transmitted through the first insulating sheet and the second insulating sheet, which allows the heat generated in the heat-generating circuit to be easily dissipated.

[0023] (7) In the substrate holder according to any one of (1) to (6), the volume resistivity of each of the first insulating sheet and the second insulating sheet is 6.7×10 12 It may be Ω·cm or more.

[0024] The first insulating sheet and the second insulating sheet have high electrical insulation properties.

[0025] (8) In any of the substrate holders (1) to (7) above, a cooling plate may be provided between the mounting plate and the heater.

[0026] The cooling plate can cool the substrate by cooling the mounting plate.

[0027] [Details of the embodiments of the present disclosure] Specific examples of substrate holders according to embodiments of the present disclosure will be described below with reference to the drawings. The same reference numerals in the drawings indicate the same or corresponding parts. The drawings are schematic, and the dimensions of the components shown in the drawings do not necessarily correspond to the actual dimensions. It should be noted that the present invention is not limited to these examples, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0028] <Substrate holder> The substrate holder of the embodiment is used, for example, in semiconductor manufacturing equipment and inspection equipment. For example, in semiconductor inspection, electrical performance of the semiconductor substrate is measured while the temperature is controlled to a predetermined value. The substrate holder of the embodiment can also be used for purposes other than inspection equipment.

[0029] [Embodiment 1] The configuration of a substrate holder 1 of embodiment 1 will be described with reference to FIGS. 1 to 3. The substrate holder 1 includes a mounting plate 2, a heater 3, and a support plate 5, in this order. The mounting plate 2, heater 3, and support plate 5 are arranged from top to bottom on the substrate holder 1. "Arranged in this order" means that the mounting plate 2, heater 3, and support plate 5 only need to be arranged in this order, and other components may be present between each component. The substrate holder 1 is a device that heats a substrate 100 placed on the upper surface 20 of the mounting plate 2 to a predetermined temperature using the heater 3. The substrate holder 1 is supported by a pedestal 7, which will be described later. The components of the substrate holder 1 will be described in detail below. FIG. 1 is a schematic cross-sectional view of the substrate holder 1. To make the configuration of the substrate holder 1 easier to understand, FIG. 1 also schematically illustrates the heater 3, as well as the arrangement of a fastening member 6 and support posts 71, which will be described later.

[0030] <Substrate> The substrate 100 is, for example, a semiconductor substrate. The shape of the substrate 100 is, for example, a disk or a rectangular plate. In other words, the planar shape of the substrate 100 when viewed from above is a circle or a polygon. The substrate 100 in this example is a quadrangular plate-shaped semiconductor substrate. The planar shape of the substrate 100 is quadrangular. A quadrangular shape is, for example, a square or a rectangle. The size of the substrate 100 is, for example, such that one side is 200 mm or more and 400 mm or less.

[0031] <Placement plate> The mounting plate 2 is a member on which the substrate 100 is placed. The mounting plate 2 has an upper surface 20 and a lower surface 21. The upper surface 20 is the surface on which the substrate 100 is placed. The lower surface 21 is the surface opposite the upper surface 20.

[0032] The shape of the mounting plate 2 is, for example, a disk or a rectangular plate. In other words, the planar shape of the mounting plate 2 when viewed from the top surface 20 is a circle or a polygon. The planar shape of the mounting plate 2 is a shape that matches the planar shape of the substrate 100. In this example, the shape of the mounting plate 2 is a square plate. In other words, the planar shape of the mounting plate 2 is a square. The size of the mounting plate 2 is slightly larger than the substrate 100. The size of the mounting plate 2 is, for example, such that one side is 210 mm or more and 410 mm or less. For example, if one side of the substrate 100 is 300 mm, one side of the mounting plate 2 is 310 mm. The size of the mounting plate 2 is the dimension in a plane parallel to the top surface 20.

[0033] The thickness of the mounting plate 2 is, for example, 5 mm to 25 mm, and further 7 mm to 20 mm. The thickness of the mounting plate 2 is the dimension of the mounting plate 2 along a direction perpendicular to the upper surface 20. If the thickness of the mounting plate 2 is 5 mm or more, the rigidity of the mounting plate 2 is high. If the thickness of the mounting plate 2 is 25 mm or less, the heat of the heater 3 is easily transferred to the upper surface 20.

[0034] The mounting plate 2 is made of a material with excellent thermal conductivity and high rigidity. The material of the mounting plate 2 is, for example, a metal, a ceramic, or a composite containing ceramic. The metal forming the mounting plate 2 is, for example, copper, a copper alloy, aluminum, or an aluminum alloy. The ceramic forming the mounting plate 2 is, for example, silicon carbide, aluminum nitride, aluminum oxide, or silicon nitride. The composite containing ceramic forming the mounting plate 2 is, for example, a composite of silicon and silicon carbide, a composite of aluminum and silicon carbide, or a composite of aluminum, silicon, and silicon carbide. The above metals have high thermal conductivity. If the mounting plate 2 is made of the above metal, the mounting plate 2 easily conducts heat. Therefore, the substrate 100 can be heated efficiently. The above ceramics or composites containing ceramics have higher rigidity than metals. If the mounting plate 2 is made of the above ceramics or composites containing ceramics, the mounting plate 2 is less likely to deform. Therefore, the thickness of the mounting plate 2 can be reduced. The material of the mounting plate 2 in this example is a composite of silicon and silicon carbide (Si—SiC).

[0035] The thermal conductivity of the support plate 2 is, for example, 100 W / m·K or more. The thermal conductivity of the support plate 2 may further be 200 W / m·K or more, 300 W / m·K or more, or 400 W / m·K or more. These thermal conductivities are values ​​at 20°C. The thermal conductivity of copper is approximately 400 W / m·K, and the thermal conductivity of aluminum is approximately 230 W / m·K. The thermal conductivity of silicon carbide is approximately 200 W / m·K, the thermal conductivity of aluminum nitride is approximately 150 W / m·K, the thermal conductivity of aluminum oxide is approximately 30 W / m·K, the thermal conductivity of silicon nitride is approximately 30 W / m·K, and the thermal conductivity of Si-SiC is approximately 170 W / m·K.

[0036] The surface of the mounting plate 2 may be subjected to a surface treatment. The surface treatment is, for example, plating. Specific examples of plating are nickel plating or nickel-phosphorus plating. The plating method is electrolytic plating or electroless plating.

[0037] Although not shown here, the mounting plate 2 may be provided with a chuck mechanism that adsorbs the substrate 100 onto the upper surface 20. Adsorption of the substrate 100 onto the upper surface 20 corrects warpage of the substrate 100. Adhesion of the entire substrate 100 to the upper surface 20 makes it easier for the entire substrate 100 to be heated uniformly.

[0038] Furthermore, a temperature sensor (not shown) may be provided on the mounting plate 2. This temperature sensor measures the temperature of the mounting plate 2. The temperature of the heater 3 is controlled based on the temperature of the mounting plate 2 measured by the temperature sensor. When the substrate holder 1 includes a cooling plate 8 shown in FIG. 4 (to be described later), the temperature sensor may be provided on the cooling plate 8.

[0039] <Heater> The heater 3 heats the mounting plate 2, thereby heating the substrate 100. The heater 3 has a circular or polygonal planar shape when viewed from above. The planar shape of the heater 3 matches the planar shape of the mounting plate 2. In this example, the planar shape of the heater 3 is a square. The size of the heater 3 is the same as the size of the mounting plate 2.

[0040] The heater 3 is disposed on the lower surface 21 of the mounting plate 2. The heater 3 is supported by a support plate 5. In this example, the heater 3 is sandwiched between the mounting plate 2 and the support plate 5. The upper surface of the heater 3 is in contact with the mounting plate 2. The lower surface of the heater 3 is in contact with the support plate 5.

[0041] As shown in FIGS. 2 and 3, the heater 3 includes a heater substrate 30, a first insulating sheet 41, and a second insulating sheet 42. FIG. 2 is a schematic cross-sectional view of a portion of the heater 3. FIG. 3 shows the heater substrate 30, the first insulating sheet 41, and the second insulating sheet 42 separated from each other to facilitate understanding of the heater 3's configuration. FIG. 3 also indicates the thickness of each component of the heater 3. The heater substrate 30 is disposed between the first insulating sheet 41 and the second insulating sheet 42. The first insulating sheet 41, the heater substrate 30, and the second insulating sheet 42 are disposed on the heater 3 in this order from above. The heater substrate 30 is not bonded to either the first insulating sheet 41 or the second insulating sheet 42. As shown in FIG. 1, the first insulating sheet 41 contacts the mounting plate 2, and the second insulating sheet 42 contacts the support plate 5.

[0042] [Heater board] As shown in Figure 2, the heater substrate 30 has a structure in which a heat generating circuit 31 is sandwiched between insulating films 32. The heat generating circuit 31 is sheet-shaped. The insulating film 32 has a first insulating film 32a and a second insulating film 32b. Arranged from the top of the heater substrate 30 are the first insulating film 32a, the heat generating circuit 31, and the second insulating film 32b. The first insulating film 32a is in contact with the top surface of the heat generating circuit 31. The second insulating film 32b is in contact with the bottom surface of the heat generating circuit 31.

[0043] The heater substrate 30 in this example has a rectangular planar shape. The size of the heater substrate 30 is equal to the size of the mounting plate 2. The heater substrate 30 has through holes formed therein, through which the fastening members 6 shown in FIG. 1 are inserted. The heater substrate 30 also has through holes formed therein, through which the support posts 71 shown in FIG. 1 are inserted.

[0044] <Heat generating circuit> The heating circuit 31 is formed by a heating element. The heating circuit 31 has a wiring portion 31w through which a current flows. The heating element is a material that generates heat when a current flows through it. The heating element is, for example, a metal such as stainless steel or nickel-chromium steel. When a current flows through the heating circuit 31, the heating circuit 31 generates heat and heat is generated from the heater 3. The heating circuit 31 is designed so that when the heater 3 heats the mounting plate 2, the temperature distribution on the upper surface 20 is maintained uniform. The heating circuit 31 in this example is formed by processing a metal foil into a predetermined shape. The processing of the metal foil is, for example, etching or laser processing. The heating circuit 31 in this example is processed from stainless steel foil.

[0045] Thickness 3, i.e., the thickness t1 of the wiring portion 31w, may be any thickness that provides an appropriate amount of heat when a current flows through the heat generating circuit 31. The thickness t1 of the heat generating circuit 31 is, for example, 0.01 mm or more and 0.5 mm or less, or even 0.02 mm or more and 0.1 mm or less. The thickness t1 of the heat generating circuit 31 in this example is 0.05 mm.

[0046] <Insulating film> The insulating film 32 electrically insulates the heat generating circuit 31 and mechanically protects the heat generating circuit 31. The size of the insulating film 32 is slightly larger than the size of the heat generating circuit 31. The heat generating circuit 31 is arranged so as not to protrude from the insulating film 32.

[0047] "material" The insulating film 32 is formed from an insulating resin that has excellent heat resistance and high tensile strength. The heat resistance temperature of the insulating film 32 is, for example, 200°C or higher. If the heat resistance temperature of the insulating film 32 is 200°C or higher, the insulating film 32 is less likely to be damaged by the heat generated by the heat generating circuit 31. The heat resistance temperature of the insulating film 32 may be 210°C or higher. The high tensile strength of the insulating film 32 can restrict the elongation of the heat generating circuit 31 due to thermal expansion. Therefore, displacement of the heat generating circuit 31 due to thermal expansion is less likely to occur. The tensile strength of the insulating film 32 is, for example, 100 MPa or higher. The material of the insulating film 32 is, for example, polyimide. The insulating film 32 in this example is a polyimide film.

[0048] Thickness The thickness t2 of the insulating film 32 shown in FIG. 3, i.e., the thickness t2 of each of the first insulating film 32a and the second insulating film 32b, is, for example, 0.01 mm to 1 mm, or even 0.02 mm to 0.1 mm. Having the thickness t2 of the insulating film 32 of 0.01 mm or more facilitates electrical insulation and mechanical protection of the heat-generating circuit 31. Having the thickness t2 of the insulating film 32 of 1 mm or less reduces the thickness of the heater substrate 30. This allows for a thinner heater 3, enabling the heater 3 to be installed in the limited space of the substrate holder 1. Furthermore, having the thickness t2 of the insulating film 32 of 1 mm or less facilitates dissipation of heat generated by the heat-generating circuit 31. This reduces excessive temperature rise in the heat-generating circuit 31 and prevents the heat-generating circuit 31 from becoming abnormally hot. The thickness t2 of the insulating film 32 may be 0.01 mm to 0.5 mm, or even 0.05 mm to 0.5 mm. If the thickness t2 of the insulating film 32 is 0.05 mm or more, it is easy to reliably provide electrical insulation and mechanical protection for the heat generating circuit 31. If the thickness t2 of the insulating film 32 is 0.5 mm or less, heat dissipation from the heat generating circuit 31 is more efficient. The thickness t2 of the first insulating film 32a and the thickness t2 of the second insulating film 32b may be the same or different. The thickness t2 of the insulating film 32 in this example is 0.05 mm.

[0049] The first insulating film 32a and the second insulating film 32b are bonded together by adhesive or fusion. In the portion of the heat generating circuit 31 where the wiring portion 31w is located, the first insulating film 32a is bonded to the upper side of the wiring portion 31w, and the second insulating film 32b is bonded to the lower side of the wiring portion 31w.

[0050] As shown in Figures 2 and 3, the heater substrate 30 has a different thickness between the portion where the wiring portion 31w of the heat generating circuit 31 is present and the portion where the wiring portion 31w is not present. The thickness of the heater substrate 30 in the portion where the wiring portion 31w is not present is smaller than the thickness of the heater substrate 30 in the portion where the wiring portion 31w is present. The thickness of the portion where the wiring portion 31w of the heat generating circuit 31 is not present is the total thickness of the thickness t2 of the first insulating film 32a and the thickness t2 of the second insulating film 32b. The thickness of the portion where the wiring portion 31w is present is the total thickness of the thickness t1 of the wiring portion 31w, the thickness t2 of the first insulating film 32a and the thickness t2 of the second insulating film 32b. In this example, the thickness of the heater substrate 30 in the portion where the wiring portion 31w is not present is 0.15 mm, and the thickness of the heater substrate 30 in the portion where the wiring portion 31w is present is 0.10 mm.

[0051] Recesses 30d corresponding to the heat generating circuits 31 are formed on the top and bottom surfaces of the heater substrate 30. In other words, both surfaces of the heater substrate 30 are uneven. The depth d of the recesses 30d is approximately half the thickness t1 of the heat generating circuits 31. In this example, the depth d of the recesses 30d is 0.025 mm.

[0052] [First insulation sheet and second insulation sheet] The first insulating sheet 41 contacts the upper surface of the heater substrate 30. The second insulating sheet 42 contacts the lower surface of the heater substrate 30. When the heater 3 is installed on the substrate holder 1 as shown in FIG. 1, the first insulating sheet 41 and the second insulating sheet 42 are compressed while sandwiched between the mounting plate 2 and the support plate 5. As the first insulating sheet 41 and the second insulating sheet 42 are compressed, the first insulating sheet 41 and the second insulating sheet 42 are pressed against the heater substrate 30 as shown in FIG. 2. The first insulating sheet 41 deforms to fit into the recess 30d formed on the upper surface of the heater substrate 30 and comes into close contact with the upper surface of the heater substrate 30. The second insulating sheet 42 deforms to fit into the recess 30d formed on the lower surface of the heater substrate 30 and comes into close contact with the lower surface of the heater substrate 30. Therefore, voids are less likely to occur in the recesses 30d formed on both sides of the heater substrate 30.

[0053] Because voids are unlikely to occur in the recess 30d, heat transfer between the heater substrate 30 and the first insulating sheet 41, and between the heater substrate 30 and the second insulating sheet 42, is unlikely to be hindered. Heat generated in the heat generating circuit 31 is transferred to the first insulating sheet 41 and the second insulating sheet 42. The heat transferred to the first insulating sheet 41 is transferred to the mounting plate 2. Because heat transfer is unlikely to be hindered by voids, the heat generated in the heat generating circuit 31 is likely to be transferred evenly to the mounting plate 2. This makes it easier to achieve a uniform temperature distribution on the upper surface of the mounting plate 2. In addition, the heat generated in the heat generating circuit 31 is likely to be dissipated through the first insulating sheet 41 and the second insulating sheet 42. This reduces excessive temperature rise in the heat generating circuit 31, making it less likely that the heat generating circuit 31 will become abnormally high.

[0054] In this example, the first insulating sheet 41 and the second insulating sheet 42 each have a rectangular planar shape. The size of each of the first insulating sheet 41 and the second insulating sheet 42 is equal to the size of the heater substrate 30. The first insulating sheet 41 and the second insulating sheet 42 each have a through hole through which the fastening member 6 shown in FIG. 1 is inserted. The first insulating sheet 41 and the second insulating sheet 42 also have a through hole through which the support post 71 shown in FIG. 1 is inserted. With the heater substrate 30 sandwiched between the first insulating sheet 41 and the second insulating sheet 42, the fastening member is inserted into each through hole. This prevents the first insulating sheet 41 and the second insulating sheet 42 from shifting in position even if the first insulating sheet 41 and the second insulating sheet 42 are not bonded to the heater substrate 30.

[0055] <material> The first insulating sheet 41 and the second insulating sheet 42 are formed of an insulating resin with excellent heat resistance, elasticity, and thermal conductivity. The heat resistance temperature of each of the first insulating sheet 41 and the second insulating sheet 42 is, for example, 200°C or higher. If the heat resistance temperature of each of the first insulating sheet 41 and the second insulating sheet 42 is 200°C or higher, the first insulating sheet 41 and the second insulating sheet 42 are less likely to be damaged by the heat generated by the heating circuit 31. The heat resistance temperature of each of the first insulating sheet 41 and the second insulating sheet 42 may be 210°C or higher. The elasticity of the first insulating sheet 41 and the second insulating sheet 42 allows them to easily deform to fit into the recesses 30d formed on both sides of the heater substrate 30. This makes it less likely that voids will form in the recesses 30d. The thermal conductivity of the first insulating sheet 41 and the second insulating sheet 42 allows them to easily transfer heat generated by the heating circuit 31.

[0056] The material of each of the first insulating sheet 41 and the second insulating sheet 42 is, for example, silicone resin filled with a filler, and the filler is a ceramic filler. The filler is, for example, granular or fibrous. The ceramic filler material is, for example, boron nitride, aluminum nitride, aluminum oxide, or silicon oxide. Silicone resin filled with a filler can improve thermal conductivity compared to silicone resin alone. Furthermore, a reinforcing material such as glass cloth may be embedded in the first insulating sheet 41 and the second insulating sheet 42. In this example, the first insulating sheet 41 and the second insulating sheet 42 are formed from silicone resin filled with a filler. Glass cloth is embedded in the first insulating sheet 41 and the second insulating sheet 42 as a reinforcing material.

[0057] Thickness The thickness t3 of each of the first insulating sheet 41 and the second insulating sheet 42 shown in FIG. 3 is greater than half the thickness t1 of the heating circuit 31. In other words, the thickness t3 of each of the first insulating sheet 41 and the second insulating sheet 42 is greater than the depth d of the recess 30d. The thickness t3 is the thickness in the natural state. The natural state is a state in which no external force is applied and no compression is present. When the thickness t3 is greater than half the thickness t1, the first insulating sheet 41 and the second insulating sheet 42 deform to fit into the recess 30d, preventing voids from forming in the recess 30d. The thickness t3 may be greater than or equal to the thickness t1. The greater the thickness t3, the more easily the first insulating sheet 41 and the second insulating sheet 42 deform to fit into the recess 30d. This reduces the likelihood of voids forming in the recess 30d. In addition, recesses are less likely to form on the surfaces of the first insulating sheet 41 and the second insulating sheet 42.

[0058] The thickness t3 of each of the first insulating sheet 41 and the second insulating sheet 42 may be appropriately set according to the thickness t1 of the heat-generating circuit 31. The thicker the first insulating sheet 41 and the second insulating sheet 42, the greater their thermal resistance. Therefore, heat transfer through the first insulating sheet 41 and the second insulating sheet 42 becomes slower. The upper limit of the thickness t3 is, for example, 1.0 mm. Setting the thickness t3 to 1.0 mm or less allows the heater 3 to be thinned, enabling the heater 3 to be installed in the limited space of the substrate holder 1. Furthermore, if the thickness t3 is 1.0 mm or less, heat generated by the heat-generating circuit 31 is easily dissipated through the first insulating sheet 41 and the second insulating sheet 42. This reduces excessive temperature rise in the heat-generating circuit 31 and makes it less likely for the heat-generating circuit 31 to become abnormally high. A specific thickness t3 is, for example, 0.1 mm to 1.0 mm, and more preferably 0.2 mm to 0.8 mm. In this example, the thickness t3 of each of the first insulating sheet 41 and the second insulating sheet 42 is 0.5 mm.

[0059] <Hardness> The hardness of each of the first insulating sheet 41 and the second insulating sheet 42 is less than the hardness of the insulating film 32. In other words, each of the first insulating sheet 41 and the second insulating sheet 42 is softer than the insulating film 32. Because the hardness of each of the first insulating sheet 41 and the second insulating sheet 42 is less than the hardness of the insulating film 32, the first insulating sheet 41 and the second insulating sheet 42 are more likely to deform and enter the recess 30d. This makes it less likely that a gap will be formed in the recess 30d.

[0060] The specific hardness of each of the first insulating sheet 41 and the second insulating sheet 42 is, for example, 10 or more and 90 or less in durometer A. If the hardness of each of the first insulating sheet 41 and the second insulating sheet 42 is 90 or less in durometer A, the first insulating sheet 41 and the second insulating sheet 42 can deform to fit into the recess 30d, preventing voids from forming in the recess 30d. The hardness of each of the first insulating sheet 41 and the second insulating sheet 42 may be 60 or more and 90 or less in durometer A, or even 80 or more and 90 or less. In this example, the hardness of each of the first insulating sheet 41 and the second insulating sheet 42 is 88 or more and 90 or less in durometer A.

[0061] <Thermal conductivity> The thermal conductivity of each of the first insulating sheet 41 and the second insulating sheet 42 is, for example, 3.0 W / m·K or more. The thermal conductivity of each of the first insulating sheet 41 and the second insulating sheet 42 is the thermal conductivity in the direction along the thickness of each of the first insulating sheet 41 and the second insulating sheet 42. This thermal conductivity is a value at 20°C. When the thermal conductivity of each of the first insulating sheet 41 and the second insulating sheet 42 is 3.0 W / m·K or more, heat is easily transmitted through the first insulating sheet 41 and the second insulating sheet 42. This facilitates dissipation of heat generated in the heat-generating circuit 31. This reduces excessive temperature rise in the heat-generating circuit 31 and makes it less likely for the heat-generating circuit 31 to become abnormally high. The thermal conductivity of each of the first insulating sheet 41 and the second insulating sheet 42 may be 4.0 W / m·K or more, or even 5.0 W / m·K or more.

[0062] <Volume resistivity> The volume resistivity of each of the first insulating sheet 41 and the second insulating sheet 42 is, for example, 6.7×10 12 The higher the volume resistivity, the better the electrical insulation. The volume resistivity of each of the first insulating sheet 41 and the second insulating sheet 42 is 6.7×10 12 The first insulating sheet 41 and the second insulating sheet 42 have high electrical insulation properties due to the resistivity being Ω·cm or more. The volume resistivity of each of the first insulating sheet 41 and the second insulating sheet 42 is 1.0×10 13Ω·cm or more, and 5.0×10 13 It may be Ω·cm or more.

[0063] ≪Support plate≫ As shown in FIG. 1, the support plate 5 is a member that supports the heater 3 between itself and the mounting plate 2. The support plate 5 is disposed on the underside of the heater 3. The support plate 5 is formed of a material that is more rigid than the heater 3. The material of the support plate 5 is, for example, a metal, a ceramic, or a composite material containing ceramic. The material of the support plate 5 can be any of the materials listed as the materials for the mounting plate 2, or stainless steel or Kovar.

[0064] The support plate 5 is formed with through holes through which the fastening members 6 shown in Fig. 1 are inserted. The support plate 5 is also formed with through holes through which the support posts 71 shown in Fig. 1 are inserted.

[0065] <Fastening components> The fastening member 6 fastens the mounting plate 2, heater 3, and support plate 5 together. The heater 3 and support plate 5 are fixed to the mounting plate 2 by the fastening member 6. As shown in FIG. 1 , the fastening member 6 is inserted from below the support plate 5 and connected to the underside 21 of the mounting plate 2. The fastening member 6 is, for example, a bolt. The underside 21 is provided with an internal thread to which an external thread formed at the tip of the bolt is connected. The fastening member 6 in this example has a length that penetrates through the heater 3 and support plate 5. When the heater 3 is sandwiched between the mounting plate 2 and the support plate 5 and tightened by the fastening member 6, the first insulating sheet 41 and the second insulating sheet 42 are compressed. The fastening member 6 in this example is a bolt.

[0066] <Pedestal> The base 7 is a member that supports the substrate holder 1. The material of the base 7 is, for example, metal, ceramic, or a composite containing ceramic. The materials listed as the materials for the mounting plate 2 can be used as the material of the base 7.

[0067] The pedestal 7 in this example has a support pillar 71 extending upward from the upper surface of the pedestal 7. The support pillar 71 supports the substrate holder 1 so that a space is formed between the substrate holder 1 and the pedestal 7. The support pillar 71 in this example penetrates the heater 3 and the support plate 5, and has a length that reaches from the upper surface of the pedestal 7 to the lower surface 21 of the mounting plate 2. The support pillar 71 is cylindrical.

[0068] [Embodiment 2] The configuration of a substrate holder 1 of embodiment 2 will be described with reference to Figure 4. The substrate holder 1 of embodiment 2 differs from the substrate holder 1 of embodiment 1 shown in Figure 1 in that it includes a cooling plate 8. The cooling plate 8 is disposed between the mounting plate 2 and the heater 3. The cooling plate 8 and the mounting plate 2 may be insulated by an insulator (not shown). In the substrate holder 1 of embodiment 2, the mounting plate 2, cooling plate 8, heater 3, and support plate 5 are disposed in this order from the top of the substrate holder 1. A fastening member 6 penetrates the cooling plate 8, heater 3, and support plate 5, and is joined to the underside 21 of the mounting plate 2.

[0069] ≪Cooling plate≫ The cooling plate 8 is used, for example, to cool the substrate 100 heated by the heater 3. The cooling plate 8 cools the substrate 100 by cooling the mounting plate 2. The cooling plate 8 of this example has a flow path 80 for flowing a coolant inside the cooling plate 8. The cooling plate 8 is provided with a supply port 81 for supplying the coolant to the flow path 80 and an outlet 82 for discharging the coolant from the flow path 80. Although not shown here, the supply port 81 and the outlet 82 are each connected to a tank that stores the coolant by piping. The coolant is pumped from the tank to the supply port 81 by a pump. The coolant is returned to the tank from the outlet 82. The coolant flowing through the flow path 80 cools the cooling plate 8 and thus the mounting plate 2. After the substrate 100 is heated, the cooling plate 8 cools the mounting plate 2, thereby quickly cooling the substrate 100. The cooling plate 8 is made of a material such as a metal, ceramic, or a composite containing ceramics. The cooling plate 8 can be made of the same material as that of the mounting plate 2 .

[0070] In the substrate holder 1 shown in FIG. 4, the cooling plate 8 is disposed on the lower surface 21 of the mounting plate 2 , but the cooling plate 8 may also be disposed on the lower surface of the support plate 5 .

[0071] [Test Example 1] A simulation was conducted to verify the uniform heating performance of the heater with or without an insulating sheet, and the effect of the insulating sheet on the uniform heating performance of the heater was evaluated. For this test, two types of models were prepared, one with an insulating sheet and one without.

[0072] <Model No. 1> The heater of model No. 1 has an insulating sheet. Figure 5 is a schematic cross-sectional view of a portion of model No. 1. As shown in Figure 5, the heater 3a of model No. 1 has a heater substrate 30 disposed between a first insulating sheet 41 and a second insulating sheet 42. The heater 3a of model No. 1 has the same configuration as the heater 3 shown in Figure 2.

[0073] <Model No.2> The heater of model No. 2 does not have an insulating sheet. Figure 6 is a schematic cross-sectional view of a portion of model No. 2. Unlike the heater 3 of model No. 1 shown in Figure 5, the heater 3b of model No. 2 has only a heater substrate 30.

[0074] Models were created in which a heater was sandwiched between two metal plates. In model No. 1, as shown in FIG. 5, a metal plate 51 was placed on the upper surface of heater 3a, and metal plate 51 was in contact with first insulating sheet 41. In addition, a metal plate 52 was placed on the lower surface of heater 3a, and metal plate 52 was in contact with second insulating sheet 42. In model No. 2, as shown in FIG. 6, a metal plate 51 was placed on the upper surface of heater substrate 30, and metal plate 52 was placed on the lower surface of heater substrate 30. In model No. 2, gaps were created in recesses 30d formed on both sides of heater substrate 30.

[0075] Each model is composed of a metal plate 51, a heater 3a or 3b, and a metal plate 52 stacked on top of each other in this order. When viewed from above, each model has a square shape. The size of each model is 150 mm long and 150 mm wide.

[0076] The thickness t1 of the heating circuit 31, the thickness t2 of each of the first insulating film 32a and the second insulating film 32b, and the thickness t5 of each of the metal plates 51 and 52 are shown below. Also, for model No. 1, the minimum thickness t4 of each of the first insulating sheet 41 and the second insulating sheet 42 is shown below. Thickness t1: 0.05 mm Thickness t2: 0.05 mm Thickness t5: 3.0 mm Minimum thickness t4: 1.0 mm

[0077] The width w1 of the wiring portion 31w and the width w2 of the recess 30d are shown below. Width w1: 2.0mm Width w2: 1.0mm

[0078] The thermal conductivity of metal plates 51 and 52 is 300 W / m·K. The thermal conductivity of each of first insulating film 32a and second insulating film 32b is 0.3 W / m·K. The thermal conductivity of each of first insulating sheet 41 and second insulating sheet 42 is 5.0 W / m·K.

[0079] For Model No. 1 and Model No. 2, the temperature distribution on the top surface of the metal plate 51 when the heating circuit 31 generates heat was analyzed by simulation. In this simulation, the heating circuit 31 was set to 100°C, and the temperatures at measurement points set on the top surface of the metal plate 51 were obtained. Figure 7 shows the arrangement of measurement points p on the top surface of the metal plate 51. In Figure 7, the measurement points p are indicated by black circles. There are a total of 25 measurement points p, five vertically and five horizontally.

[0080] For Model No. 1 and Model No. 2, the difference between the highest and lowest temperatures was calculated from 25 measurement points. As a result, for Model No. 1, the temperature difference was 0.02°C. In contrast, for Model No. 2, the temperature difference was 0.1°C. From these results, it can be seen that heaters with insulating sheets have better temperature uniformity than heaters without insulating sheets. [Explanation of symbols]

[0081] 1 Board holder 2. Mounting plate 20 top, 21 bottom 3, 3a, 3b heater 30 heater substrate, 30d recess 31 Heat generating circuit, 31w wiring section 32 Insulating film 32a: First insulating film; 32b: Second insulating film 41 First insulating sheet 42 Second insulating sheet 5 Support plate 6 Fastening members 7. Pedestal 71 Pillar 8 cooling plate, 80 flow path, 81 supply port, 82 discharge port 100 boards 51, 52 metal plate t1, t2, t3, t5 thickness t4 minimum thickness d depth w1, w2 width p measurement point

Claims

1. a mounting plate having an upper surface on which a substrate is placed, a heater, and a support plate, in this order; The heater is a first insulating sheet and a second insulating sheet; a heater substrate disposed between the first insulating sheet and the second insulating sheet, The heater substrate has a structure in which a heating circuit is sandwiched between insulating films, the thickness of each of the first insulating sheet and the second insulating sheet is greater than half the thickness of the heating circuit; the hardness of each of the first insulating sheet and the second insulating sheet is less than the hardness of the insulating film; Substrate holder.

2. 2. The substrate holder according to claim 1, wherein the material of each of the first insulating sheet and the second insulating sheet is a silicone resin filled with a filler.

3. 3. The substrate holder according to claim 1, wherein the insulating film is made of polyimide.

4. 3. The substrate holder according to claim 1, wherein the hardness of each of the first insulating sheet and the second insulating sheet is 10 or more and 90 or less in durometer A.

5. 3. The substrate holder according to claim 1, wherein the thickness of each of the first insulating sheet and the second insulating sheet is equal to or greater than the thickness of the heating circuit.

6. 3. The substrate holder according to claim 1, wherein the first insulating sheet and the second insulating sheet each have a thermal conductivity of 3.0 W / m·K or higher.

7. The first insulating sheet and the second insulating sheet each have a volume resistivity of 6.7×10 １２ 3. The substrate holder according to claim 1, wherein the resistivity is Ω·cm or more.

8. 3. The substrate holder according to claim 1, further comprising a cooling plate between said mounting plate and said heater.

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