Electrostatic Chuck Device

Abstract

To provide an electrostatic chuck device that can uniformly cool or heat a substrate that is sucked and fixed.SOLUTION: An electrostatic chuck device includes an electrostatic chuck plate, a bonding layer including a bonding agent bonded on a back surface of the electrostatic chuck plate, and a base 30 including a bonding surface 31 bonded to the bonding layer and including a plurality of projections 32 extending radially from a center part of the bonding surface 31 to the outer peripheral part. End parts of the projections 32 on the center part side may be disposed with a space therebetween. The electrostatic chuck device sucks and fixes a sample with electrostatic power on a suction surface of the electrostatic chuck plate.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an electrostatic chuck device. [Background technology]

[0002] An electrostatic chuck device includes an electrostatic chuck plate that attracts a sample such as a wafer by electrostatic force, and a base including a cooling mechanism. When indium or aluminum is used as a bonding agent for bonding the electrostatic chuck plate to the base, the thickness of the bonding layer is controlled by a masking tape or a wire. Alternatively, the thickness of the bonding layer may be controlled by the thickness of the coating of the bonding agent without introducing a member for controlling such a thickness.

[0003] For example, Patent Document 1 describes that in bonding using indium, the thickness of the bonding layer is controlled by using masking tape.

[0004] Furthermore, Patent Document 2 describes that the thickness of the bonding layer is controlled by the film thickness or foil to which the bonding agent is applied. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-104964 A [Patent Document 2] Patent No. 3485390 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with the method of Patent Document 1, variations in the thickness of the masking tape are directly reflected in variations in the thickness of the bonding layer, making it difficult to maintain the accuracy of the thickness of the bonding layer.

[0007] In addition, in the method of controlling the thickness of the bonding layer by placing wires, it is difficult to specify the position of the wires. For example, the contact heat transfer between the base and the electrostatic chuck plate varies depending on the placement of the wires. In addition, the placement of the wires can cause foreign matter to get mixed into the bonding agent. This can locally change the properties of the bonding agent, which can also cause stress concentration.

[0008] In addition, the wire arrangement may cause the adhesive to be divided, hindering the movement of the adhesive when it expands or contracts due to differences in thermal expansion. This can cause variations in the thickness of the bonding layer after bonding, which can lead to uneven contact heat transfer. In addition, the adhesive is prone to damage in environments where thermal expansion and contraction occur. Depending on the wire material, it may not be possible to apply the necessary pressure during bonding, resulting in variations in the thickness of the bonding layer.

[0009] As described above, in the method using masking tape or wire, it is difficult to control the thickness of the bonding layer with high precision.

[0010] In the method of Patent Document 2, there is no function as a stopper to adjust the thickness of the bonding layer, so it is difficult to correct variations in the thickness of the bonding layer, and as a result, the thickness of the bonding layer cannot be controlled with high precision.

[0011] In addition, in the case of resin adhesive, there is a method of controlling the thickness of the bonding layer by using a hardened resin adhesive or a ceramic plate. However, in the case of a hardened resin adhesive, deformation due to load occurs, and it is not possible to apply a sufficient load required for thickness adjustment. When a ceramic plate is used, stress concentration occurs as in the case of a wire, which may lead to damage to the electrostatic chuck plate.

[0012] The present invention has been made in consideration of the above problems, and provides an electrostatic chuck device that can control the thickness of a bonding layer between an electrostatic chuck plate and a base with high precision and can uniformly cool or heat a sample that is attracted and fixed thereto. [Means for solving the problem]

[0013] An electrostatic chuck device according to the present invention includes an electrostatic chuck plate, a bonding layer containing a bonding agent bonded to a back surface of the electrostatic chuck plate, and a base including a bonding surface bonded to the bonding layer and on which a plurality of protrusions are formed extending radially from a center of the bonding surface toward an outer periphery.

[0014] In the electrostatic chuck device, the ends of the projections on the central portion side may be arranged with a gap therebetween.

[0015] In the electrostatic chuck device, the joining surface may have a flat central portion at the center surrounded by the end portions.

[0016] In the above electrostatic chuck device, the multiple protrusions may include a plurality of first protrusions having a first length in a direction in which the protrusions extend, and a plurality of second protrusions having a second length shorter than the first length, and an end portion on the central side of the second protrusions may be positioned closer to the outer periphery than an end portion on the central side of the first protrusions.

[0017] In the electrostatic chuck device, a hole may be formed in the bonding surface near an end portion of the second projection on the central portion side.

[0018] In the electrostatic chuck device, ends of at least two of the protrusions on the central portion side may be connected to each other.

[0019] In the electrostatic chuck device, the protrusions may be embedded in the bonding agent.

[0020] In the electrostatic chuck device, the protrusion may be in direct contact with the rear surface, and an area of ​​the protrusion in contact with the rear surface may be 60% or less of an area of ​​the rear surface.

[0021] In the electrostatic chuck device, the base may include a flow path through which a coolant flows.

[0022] In the electrostatic chuck device, the Young's modulus of the base is 200 [GPa] or more, and the difference between the thermal expansion coefficient of the base and the thermal expansion coefficient of the electrostatic chuck plate is 1×10 -6 [ / °C] and the thermal conductivity of the base may be 50 [W / (mK)] or more.

[0023] In the electrostatic chuck device described above, the base may include at least one of aluminum, a metal matrix composite material, silicon carbide and silicon, aluminum oxide, and aluminum nitride.

[0024] In the electrostatic chuck device, the electrostatic chuck plate may include an internal electrode and may contain at least one of yttrium oxide, silicon carbide, aluminum oxide, and aluminum nitride.

[0025] In the above-described electrostatic chuck device, the bonding agent may be one containing at least one of indium, aluminum, silver, and tin, an alloy containing at least one of indium, aluminum, silver, and tin, or one containing at least one of a silicone resin, an acrylic resin, and an epoxy resin.

[0026] The bonding agent may include a thermosetting resin, have a thermal conductivity of 4.0 [W / (mK)] or more, and have a Young's modulus of 1 [GPa] or less at -150 [°C].

[0027] In the bonding agent, when cooled from 23°C to -150°C, the rate of change in Young's modulus is less than 500%, and when cooled from 23°C to -150°C, the tensile load is 12.6 cm 2 ] per area may be 15 times or less.

[0028] The bonding agent may contain at least one of a silicone resin, an epoxy resin, and an acrylic resin, and may have a decomposition temperature of 260° C. or higher.

[0029] The bonding agent may contain 35% to 45% of a thermally conductive filler, the thermally conductive filler having a particle size D90 of 25 μm or less and a particle size D50 of less than 10 μm, and the viscosity of the bonding agent may be 10 Pa·s or less.

[0030] The decomposition temperature of the bonding agent before heat curing is 300°C or higher, the bonding agent contains a thermally conductive filler, and the thermally conductive filler may have a particle size D90 of 25 μm or less and a particle size D50 of less than 10 μm.

[0031] The thermally conductive filler contained in the bonding agent may include at least one of aluminum nitride, silicon nitride, boron nitride, and silicon carbide.

[0032] Both the electrostatic chuck plate and the base may contain at least one of aluminum, yttrium oxide, silicon carbide, aluminum oxide, and aluminum nitride.

[0033] The thermal expansion difference between the electrostatic chuck plate and the base is 1×10 -6 [ / ℃] is also acceptable. Effect of the Invention

[0034] According to the present invention, it is possible to provide an electrostatic chuck device capable of uniformly cooling or heating a sample that is attracted and fixed thereto. [Brief description of the drawings]

[0035] [Figure 1] 1 is a cross-sectional view illustrating an electrostatic chuck device according to a first embodiment. [Diagram 2] 2 is a plan view illustrating a bonding surface of a base in the electrostatic chuck device according to the first embodiment. FIG. [Diagram 3] 2 is a perspective view illustrating a bonding surface of a base in the electrostatic chuck device according to the first embodiment. FIG. [Figure 4] 4 is an enlarged view illustrating a bonding surface of a base in the electrostatic chuck device according to the first embodiment, showing an enlarged view of region IV in FIG. 3. [Diagram 5] 3 is a cross-sectional perspective view illustrating a protrusion of a base in the electrostatic chuck device according to the first embodiment. FIG. [Figure 6] 4A to 4C are plan views illustrating a process of thermal contraction of a bonding agent during cooling in the electrostatic chuck device according to the first embodiment. [Figure 7] 7 is a cross-sectional view illustrating a thermal contraction process of a bonding agent during cooling in the electrostatic chuck device according to the first embodiment, taken along line VII-VII in FIG. 6. [Figure 8] FIG. 4 is a diagram illustrating a model for calculating a stress generated in a bonding agent disposed between protrusions in the electrostatic chuck device according to the first embodiment. [Figure 9] FIG. 3 is a flowchart illustrating a method for manufacturing the electrostatic chuck device according to the first embodiment. [Figure 10] 10 is a perspective view illustrating a bonding surface of a base in an electrostatic chuck device according to a modified example of the first embodiment. FIG. [Figure 11] 10A to 10C are plan views illustrating a process of thermal contraction of a bonding agent during cooling in an electrostatic chuck device according to a modified example of the first embodiment. [Figure 12] 12 is a cross-sectional view illustrating a thermal contraction process of a bonding agent during cooling in an electrostatic chuck device according to a modified example of the first embodiment, taken along line XII-XII in FIG. 11. [Figure 13] 12 is a cross-sectional view illustrating a thermal contraction process of a bonding agent during cooling in an electrostatic chuck device according to a modified example of the first embodiment, taken along line XII-XII in FIG. 11. [Figure 14] FIG. 11 is a perspective view illustrating a bonding surface of a base in an electrostatic chuck device according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In addition, in each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary.

[0037] (Embodiment 1) The electrostatic chuck device according to the first embodiment will be described below. First, the <structure of the electrostatic chuck device> will be described. Then, the respective structures of the <electrostatic chuck plate>, <bonding layer>, and <base> constituting the electrostatic chuck device will be described. Then, the <manufacturing method of the electrostatic chuck device> will be described. Next, a <variation> obtained by modifying the first embodiment, and a <comparison> for comparison with the first embodiment will be described. Then, the <evaluation of the electrostatic chuck device> for the first embodiment, the variation, and the comparison will be described as <Example 1-1> to <Example 1-4>.

[0038] <Configuration of electrostatic chuck device> Fig. 1 is a cross-sectional view illustrating an electrostatic chuck device according to a first embodiment. As shown in Fig. 1, the electrostatic chuck device 1 includes an electrostatic chuck plate 10, a bonding layer 20, and a base 30. The electrostatic chuck device 1 adsorbs and fixes a sample to an adsorption surface 11 of the electrostatic chuck plate 10 by electrostatic force. The sample is, for example, a plate-shaped wafer, a sputtering target, or the like. Note that the sample is not limited to a wafer, a sputtering target, or the like, as long as it can be adsorbed to the adsorption surface 11.

[0039] Here, for convenience of explanation of the electrostatic chuck device 1, an XYZ Cartesian coordinate system is introduced. The direction perpendicular to the attraction surface 11 of the electrostatic chuck plate 10 is defined as the Z-axis direction. A plane parallel to the attraction surface 11 of the electrostatic chuck plate 10 is defined as the XY plane. For example, the attraction surface 11 side of the electrostatic chuck plate 10 is defined as the upper side, which is defined as the +Z-axis direction. The back surface 12 side of the electrostatic chuck plate 10 is defined as the lower side, which is defined as the -Z-axis direction. Note that the terms "upper" and "lower" are used for convenience of explanation of the electrostatic chuck device 1, and do not indicate the orientation in which the electrostatic chuck device 1 is actually disposed when in use.

[0040] <Electrostatic chuck plate> The electrostatic chuck plate 10 is plate-shaped and has an attraction surface 11 that attracts a sample by electrostatic force, and a back surface 12 opposite the attraction surface 11. The electrostatic chuck plate 10 is, for example, disk-shaped. Note that the electrostatic chuck plate 10 is not limited to a disk-shaped shape, and may be a rectangular plate-shaped or any other shape.

[0041] The electrostatic chuck plate 10 includes an internal electrode (not shown) inside thereof. When a voltage is applied to the internal electrode, the electrostatic chuck plate 10 attracts and fixes the sample to the attracting surface 11 by electrostatic force.

[0042] The electrostatic chuck plate 10 includes, for example, ceramics as a material. The electrostatic chuck plate 10 includes, for example, aluminum oxide (Al 2 O 3 ) and aluminum nitride (AlN).

[0043] Table 1 is a table illustrating a comparison of material properties. 2 O 3 ), Metal Matrix Composites (hereinafter referred to as MMC), Aluminum Nitride (AlN), Silicon Carbide (SiC), Indium (Indiumu) and Silicone Resin (Silicone) 3 ], thermal expansion coefficient [10 -6 / ℃], Young's modulus [GPa], Poisson's ratio and thermal conductivity [W / (mK)] are shown.

[0044] [Table 1]

[0045] As shown in Table 1, the material of the electrostatic chuck plate 10 is aluminum oxide (Al 2 O 3 ), and when the material of the base 30 is a metal matrix composite material (MMC), the difference in thermal expansion coefficient between the electrostatic chuck plate 10 and the base 30 is 1×10 -6[ / °C] or less. In addition, when the material of the electrostatic chuck plate 10 is aluminum nitride (AlN) and the material of the base 30 is silicon carbide (SiC), the difference in thermal expansion coefficient between the electrostatic chuck plate 10 and the base 30 can be reduced to 1×10 -6 By using such a material, the stress generated between the electrostatic chuck plate 10 and the base 30 can be reduced.

[0046] <Joining layer> The bonding layer 20 is disposed between the electrostatic chuck plate 10 and the base 30. The bonding layer 20 includes a bonding agent bonded to the back surface 12 of the electrostatic chuck plate 10 and the bonding surface 31 of the base 30. The bonding agent may include at least one of indium, aluminum, silver, and tin, for example. The bonding agent may also be an alloy including at least one of indium, aluminum, silver, and tin. Furthermore, the bonding agent may include at least one of silicone resin, acrylic resin, and epoxy resin.

[0047] For example, as shown in Table 1, when the bonding agent is indium or silicone resin, the thermal expansion coefficients of the electrostatic chuck plate 10 and the base 30 differ greatly from those of the bonding agent. However, in the electrostatic chuck device 1 of the present embodiment, the effect of the difference in thermal expansion coefficients can be reduced by the protrusions 32 of the base 30 described below.

[0048] When the content of pores in the bonding agent constituting the bonding layer 20 is taken as porosity, the porosity of the bonding agent is preferably 5% or less. This can improve the thermal conductivity and heat transfer coefficient between the electrostatic chuck plate 10 and the base 30, and suppress damage due to thermal expansion and thermal contraction.

[0049] <Base> The base 30 is bonded to the rear surface 12 of the electrostatic chuck plate 10 via a bonding layer 20. In the base 30, a surface bonded to the bonding layer 20 is called a bonding surface 31. Thus, the base 30 includes the bonding surface 31 bonded to the bonding layer 20.

[0050] The base 30 preferably includes a material having rigidity. For example, the base 30 may include at least one of aluminum (Al), metal matrix composite (MMC), silicon carbide (SiC), and silicon (Si). By appropriately selecting the material as described above using Table 1, the difference in the thermal expansion coefficient between the electrostatic chuck plate 10 and the base 30 can be reduced to 1×10 -6 [ / ℃] or less.

[0051] The base 30 desirably contains a material having a Young's modulus of 200 [GPa] or more. By making the Young's modulus 200 [GPa] or more, the material of the base 30 can be made rigid. Therefore, the electrostatic chuck plate 10 can be firmly pressed against the bonding surface 31 via the bonding layer 20 with any pressure. This allows the thickness of the bonding layer 20 containing a bonding agent between the electrostatic chuck plate 10 and the base 30 to be controlled with high precision by utilizing the protrusions 32 formed on the bonding surface 31.

[0052] The thermal conductivity of the base 30 is preferably 50 [W / (mK)] or more, which can improve the heat transfer from the base 30 to the electrostatic chuck plate 10 via the bonding layer 20.

[0053] FIG. 2 is a plan view illustrating the bonding surface 31 of the base 30 in the electrostatic chuck device 1 according to the embodiment 1. FIG. 3 is a perspective view illustrating the bonding surface 31 of the base 30 in the electrostatic chuck device 1 according to the embodiment 1. FIG. 4 is an enlarged view illustrating the bonding surface 31 of the base 30 in the electrostatic chuck device 1 according to the embodiment 1, and shows an enlarged view of region IV in FIG. 3. FIG. 5 is a cross-sectional perspective view illustrating the protrusions 32 of the base 30 in the electrostatic chuck device 1 according to the embodiment 1. In order to avoid complication of the figure, only some of the protrusions 32 and holes 36 are labeled, and the reference numbers of some of the protrusions 32 and holes 36 are omitted.

[0054] As shown in Figs. 2 to 5, a plurality of protrusions 32 are formed on the joint surface 31 of the base 30. The plurality of protrusions 32 extend radially from the center of the joint surface 31 toward the outer periphery. The end portion on the center side of each of the protrusions 32 is disposed at an interval from the end portion on the center side of the adjacent protrusions 32. Thus, the joint surface 31 has a flat central flat portion 33 in the center surrounded by the ends on the center side of each of the protrusions 32.

[0055] The joint surface 31 of the base 30 has a flat central flat portion 33 formed in the center, a protrusion arrangement portion 34 formed in an annular shape so as to surround the central flat portion 33, and an outer circumferential portion 35 formed in an annular shape so as to surround the protrusion arrangement portion 34. The multiple protrusions 32 are formed in the protrusion arrangement portion 34.

[0056] 5, the width 32w of the protrusion 32 is, for example, 5 to 10 mm. The height 32h of the protrusion 32 is, for example, 50 μm to 1 mm, and preferably 100 μm. Note that the width 32w and height 32h of the protrusion 32 are not limited to these values ​​and may be changed as appropriate.

[0057] 2 and 3, the multiple protrusions 32 may have multiple protrusions 32p and multiple protrusions 32q that are different in length in the direction in which the protrusions 32 extend. The length of the protrusion 32q is shorter than the length of the protrusion 32p (length of the protrusion 32p > length of the protrusion 32q). The end of the protrusion 32q on the central flat portion 33 side is disposed closer to the outer circumferential portion 35 than the end of the protrusion 32p on the central flat portion 33 side. The protrusions 32p and the protrusions 32q are collectively referred to as protrusions 32.

[0058] The end of protrusion 32p on the central flat portion 33 side is located at the boundary between the central flat portion 33 and the protrusion arrangement portion 34. The end of protrusion 32q on the central flat portion 33 side is located closer to the protrusion arrangement portion 34 than the boundary between the central flat portion 33 and the protrusion arrangement portion 34. The ends of protrusions 32p and 32q on the outer periphery 35 side are located at the boundary between the protrusion arrangement portion 34 and the outer periphery 35. The diameter of the central flat portion 33 is preferably 50 mm or more in the case of a joint surface 31 having a diameter of 300 mm, for example.

[0059] The protrusions 32 may be embedded in the bonding agent in the bonding layer 20. The protrusions 32 may be in direct contact with the rear surface 12 of the electrostatic chuck plate 10. The area of ​​the protrusions 32 in contact with the rear surface 12 of the electrostatic chuck plate 10 is preferably 60% or less of the area of ​​the rear surface 12. This can improve the heat transfer coefficient between the electrostatic chuck plate 10 and the base 30. Also, damage due to thermal expansion and thermal contraction of the bonding agent can be suppressed.

[0060] The base 30 may include a flow path (not shown) through which the coolant flows. For example, the base 30 has a built-in flow path. A hole 36 may be formed in the bonding surface 31 of the base 30. For example, wiring of the internal electrode of the electrostatic chuck plate 10 may be passed through the hole 36. When the hole 36 is formed, it is preferable to form it near the end of the central portion of the protrusion 32q. This makes it possible to increase the area of ​​the central flat portion 33 and suppress damage due to thermal expansion and thermal contraction of the bonding agent.

[0061] Fig. 6 is a plan view illustrating a process of thermal contraction of a bonding agent during cooling in the electrostatic chuck device 1 according to embodiment 1. Fig. 7 is a cross-sectional view illustrating a process of thermal contraction of a bonding agent during cooling in the electrostatic chuck device 1 according to embodiment 1, taken along line VII-VII in Fig. 6.

[0062] As shown in FIGS. 6 and 7, a plurality of radially extending protrusions 32 are formed on the bonding surface 31 of the base 30. The bonding agent thermally contracts during cooling. The direction 21 in which the bonding agent thermally contracts is the radial direction on the bonding surface 31. Therefore, the direction in which the protrusions 32 extend and the direction 21 in which the bonding agent thermally contracts are aligned, so that the stress generated between the electrostatic chuck plate 10 and the base 30 and the bonding layer 20 can be alleviated. Such stress alleviation is effective not only during cooling in the manufacturing process of the electrostatic chuck device 1, but also for thermal expansion during heating and thermal contraction during cooling when the electrostatic chuck device 1 is used.

[0063] In addition, a central flat portion 33 is formed on the bonding surface 31 of the base 30. In the central flat portion 33, the expansion and contraction of the bonding agent can be adjusted. Therefore, the bonding agent can freely deform when it undergoes thermal contraction during cooling in the manufacturing process, thermal expansion during heating and thermal contraction during cooling during use. This makes it possible to suppress sink marks and defects due to thermal expansion or thermal contraction of the bonding layer 20.

[0064] It is preferable to optimize the pitch of the arrangement of the protrusions 32 depending on the thickness of the bonding layer 20. For example, when the thickness of the bonding layer 20 is small, the pitch of the protrusions 32 is made large. This results in a bonding layer 20 containing a bonding agent that is flat in the horizontal direction. On the other hand, when the thickness of the bonding layer 20 is large, the pitch of the protrusions 32 is made small. This results in a bonding layer 20 containing a bonding agent that is elongated in the vertical direction. The amount of bonding agent contained in both bonding layers 20 can be the same.

[0065] 8 is a diagram illustrating a model for calculating a stress generated in the bonding agent disposed between the protrusions 32 in the electrostatic chuck device 1 according to the first embodiment. Since the thermal expansion coefficient of the base 30 is small, as shown in FIG. 8, when the temperature changes from T [°C] to T+ΔT [°C], the stress σ of the bonding agent and the force F generated in the bonding agent are calculated by the following formulas (1) and (2). Here, α represents the thermal expansion coefficient, ΔT represents the temperature difference, E represents the Young's modulus, and A represents the cross-sectional area of ​​the bonding agent. The cross-sectional area A is calculated from the height H and width W of the bonding agent between the protrusions 32.

[0066] σ = -αΔTE (1) F = -αΔTEA (2)

[0067] Table 2 shows examples of parameters for calculating the stress σ when the bonding agent is indium.

[0068] [Table 2]

[0069] Here, as shown in Table 2, the thermal expansion coefficient α = 30 × 10-6 [ / ℃], Young's modulus E = 11.5 [GPa], and temperature difference ΔT = -250 [℃], the stress σ is calculated to be 86.25 [MPa]. A positive value for the stress σ indicates tensile stress, and a negative value for the stress σ indicates compressive stress. Also, a positive value for the force F indicates tensile load, and a negative value for the force F indicates compressive load.

[0070] Table 3 illustrates the cross-sectional area A of the bonding agent disposed between the protrusions 32 and the force F generated in the electrostatic chuck device 1 according to the first embodiment.

[0071] [Table 3]

[0072] As shown in Table 3, the larger the cross-sectional area A of the bonding agent, the larger the force F generated in the bonding agent. For example, when the height H of the bonding agent is constant, the larger the width W of the bonding agent, the larger the force F. Also, when the width W of the bonding agent is constant, the larger the height H of the bonding agent, the larger the force F. Therefore, in order to make the force generated in the bonding layer 20 uniform, it is preferable to keep the cross-sectional area A of the bonding agent constant.

[0073] In this embodiment, the multiple protrusions 32 extend radially on the bonding surface 31. Therefore, the interval between adjacent protrusions 32 becomes wider toward the outer periphery 35 side. That is, the width W of the bonding agent becomes larger toward the outer periphery 50 side. Therefore, the multiple protrusions 32 have multiple protrusions 32p and multiple protrusions 32q having a length shorter than that of the protrusions 32p. The end of the protrusion 32q on the central flat portion 33 side is disposed closer to the outer periphery 35 side than the end of the protrusion 32p on the central flat portion 33 side. This makes it possible to reduce the width W of the bonding agent on the outer periphery 35 side, and therefore to uniformize the force F generated in the bonding agent.

[0074] <Manufacturing method of electrostatic chuck device> Next, a method for manufacturing the electrostatic chuck device 1 will be described. FIG. 9 is a flow chart illustrating a method for manufacturing the electrostatic chuck device 1 according to the first embodiment. As shown in step S11 of FIG. 9, a flow path is formed in the base 30. For example, a groove that becomes the flow path is formed by machining a lower member that constitutes the lower part of the base 30. Then, an upper member that constitutes the upper part of the base 30 is joined to the lower member in which the groove is formed with an Al brazing material. This encapsulates the flow path. In this way, the flow path is formed in the base 30.

[0075] Next, as shown in step S12, the protrusions 32 are formed. For example, after the upper and lower members are joined, the base 30 is again machined to have a required shape. Thereafter, the protrusions 32 are formed on the joining surface 31 of the base 30 by sandblasting or the like.

[0076] It may be considered that the protrusions 32 may be formed on the back surface 12 of the electrostatic chuck plate 10. However, the electrostatic chuck plate 10 is thin and easily deformed during bonding. Therefore, it is preferable to form the protrusions 32 on the bonding surface 31 of the base 30, which has a sufficient thickness and is less likely to deform.

[0077] The arrangement of the protrusions 32 can be changed according to the thickness of the bonding layer 20. For example, the pitch of the protrusions 32 may be changed within a range of 5 to 50 mm to the extent that it does not affect the bonding strength of the bonding layer 20. It is preferable that the pitch of the protrusions 32 is narrow when the bonding layer 20 is thick and is wide when the bonding layer 20 is thin.

[0078] In order to insulate the base 30, aluminum oxide (Al 2 O 3 The material may be formed into a film on the surface of the base 30 by a thermal spraying method. In that case, similar protrusions 32 may be formed on the formed thermal sprayed film.

[0079] Next, as shown in step S13, the electrostatic chuck plate 10 and the base 30 are bonded via a bonding layer. For example, an indium material is placed on the back surface 12 of the electrostatic chuck plate 10 including the internal electrode and the bonding surface 31 of the base 30, and heated to 200°C. When the indium material is melted, the back surface 12 of the electrostatic chuck plate 10 is bonded to the bonding surface 31 of the base 30. Then, a load is applied from the electrostatic chuck plate 10 side. The load is, for example, 3 kPa. Although no load is required, it is preferable to apply a load of 1 kPa or more in order to precisely control the thickness. With the load applied, the plate is heated for, for example, 30 min. Then, the heating is stopped and the plate is cooled to room temperature. It is confirmed that the indium has solidified. In this manner, the electrostatic chuck device 1 can be manufactured.

[0080] <Modification> Next, an electrostatic chuck device according to a modification of the present embodiment will be described. The electrostatic chuck device of this modification differs from that of the first embodiment in the shape of the plurality of protrusions 32. Specifically, the plurality of protrusions 32 of the modification are connected at the center.

[0081] 10 is a perspective view illustrating a joint surface 31a of a base 30a in an electrostatic chuck device according to a modification of the first embodiment. As shown in FIG. 10, in the electrostatic chuck device of this modification, the multiple protrusions 32a extend radially from the center to the outer periphery on the joint surface 31a, and the multiple protrusions 32a have multiple protrusions 32pa and multiple protrusions 32qa having a length shorter than that of the protrusions 32pa, similar to the first embodiment. However, the joint surface 31a of the base 30a of the modification does not have a central flat portion 33. Ends of the multiple protrusions 32pa on the central side are connected to each other at the center.

[0082] Fig. 11 is a plan view illustrating a process of thermal contraction of a bonding agent during cooling in an electrostatic chuck device according to a modified example of embodiment 1. Figs. 12 and 13 are cross-sectional views illustrating a process of thermal contraction of a bonding agent during cooling in an electrostatic chuck device according to a modified example of embodiment 1, taken along line XII-XII in Fig. 11.

[0083] As shown in FIG. 11, in this modified example, the extension direction of the protrusions 32a is aligned with the direction 21 of thermal contraction of the bonding agent, so that the stress generated between the electrostatic chuck plate 10 and the base 30a, and the bonding layer 20 can be alleviated.

[0084] On the other hand, in this modification, the central flat portion 33 is not formed on the bonding surface 31a of the base 30a. The ends of the central portion of the protrusions 32a are connected at the center. Therefore, due to thermal contraction after curing, defects occur near the intersection of the protrusions 32a at the center of the bonding surface 31a. For example, the bonding agent peels off from the portion where the protrusions 32a are connected at the center.

[0085] Specifically, as shown in Fig. 12, in the electrostatic chuck device 1a of the modified example, the bonding agent is filled between the electrostatic chuck plate 10 and the base 30a during the curing process. Thereafter, as shown in Fig. 13, the bonding agent near the center is peeled off due to shrinkage after curing. In this manner, in this modified example, the electrostatic chuck plate 10, the base 30a, and the bonding agent have different thermal expansion coefficients, so that the bonding agent expands and contracts on the side surface of the central protrusion 32a. Therefore, the stress resistance of the bonding layer 20 in the central part is reduced, and the bonding agent is likely to peel off from the periphery of the central protrusion 32a.

[0086] <Comparative Example> Next, an electrostatic chuck device according to a comparative example will be described. Fig. 14 is a perspective view illustrating a bonding surface 131 of a base 130 in an electrostatic chuck device according to a comparative example. As shown in Fig. 14, in the electrostatic chuck device of the comparative example, a plurality of concentric projections 132 are formed on the bonding surface 131 of the base 130. The projections 132 are formed, for example, by arranging a plurality of wires of a given diameter in a concentric shape. The other configurations are the same as those of the first embodiment.

[0087] <Evaluation of electrostatic chuck device> Next, evaluation of the electrostatic chuck devices according to the first embodiment, the modified examples, and the comparative example will be described. The evaluation items of the electrostatic chuck devices are 1. thickness of the bonding layer 20, 2. defects of the bonding layer 20, 3. temperature cycle test, and 4. temperature variation when a wafer is heated as a sample.

[0088] 1. The thickness of the bonding layer 20 is calculated from the overall thickness of the electrostatic chuck device using a three-dimensional measuring device. 2. Defects in the bonding layer 20 are inspected using an ultrasonic flaw detector from the electrostatic chuck plate 10 side of the electrostatic chuck device. 3. A temperature cycle test is performed on the electrostatic chuck device 30 times from -100°C to 100°C, and after the test, a defect inspection is performed again using an ultrasonic flaw detector. 4. The temperature variation when a wafer is heated as a sample is measured by measuring the temperature variation of the wafer substrate when a heat input of 3 kW is applied while the wafer substrate is adsorbed and fixed to the electrostatic chuck plate 10.

[0089] <Example 1-1> The electrostatic chuck device of Example 1-1 is based on the electrostatic chuck device described above in (Embodiment 1), and has a configuration in which the base 30 has a central flat portion where no protrusions 32 are formed. The material of the base 30 is a silicon carbide-aluminum (SiC-Al) composite material, and the material of the electrostatic chuck plate 10 is aluminum oxide (Al 2 O 3 ) and the material of the bonding layer 20 is indium. The bonding surface 31 of the base 30 has a plurality of protrusions 32 having the shape shown in Figures 2 to 5, and the height of the protrusions 32 is 100 [μm].

[0090] 1. Thickness of the bonding layer 20 In the electrostatic chuck device of Example 1-1, the thickness of the bonding layer 20 was within the range of 100±25 [μm], which was acceptable.

[0091] 2. Defects in the bonding layer 20 In the electrostatic chuck device of Example 1-1, the bonding layer 20 had no significant defects, and the bonding area was 99% or more, which was acceptable.

[0092] 3. Temperature cycle test In the electrostatic chuck device of Example 1-1, there was no change in the result of the defect inspection before and after the temperature cycle test, and the device passed the test.

[0093] 4. Temperature variation when a wafer is heated as a sample In the electrostatic chuck device of Example 1-1, the temperature variation of the wafer substrate was within ±3° C., which is acceptable.

[0094] <Example 1-2> The electrostatic chuck device of Example 1-2 is based on the electrostatic chuck device described above in (Embodiment 1), and has a configuration in which the base 30 has a central flat portion where no protrusions 32 are formed. The material of the base 30 is silicon carbide (SiC) with aluminum oxide (Al 2 O 3 ) is formed as a sprayed film, and the material of the electrostatic chuck plate 10 is aluminum nitride (AlN). Also, the joint surface 31 of the base 30 has a plurality of protrusions 32 having the shapes shown in Figs. 2 to 5, and the height of the protrusions 32 is 100 [μm].

[0095] 1. Thickness of the bonding layer 20 In the electrostatic chuck device of Example 1-2, the thickness of the bonding layer 20 was within the range of 100±25 [μm], which was acceptable.

[0096] 2. Defects in the bonding layer 20 In the electrostatic chuck device of Example 1-2, the bonding layer 20 had no significant defects, and the bonding area was 99% or more, which was acceptable.

[0097] 3. Temperature cycle test In the electrostatic chuck device of Example 1-2, there was no change in the result of the defect inspection before and after the temperature cycle test, and the device passed the test.

[0098] 4. Temperature variation when a wafer is heated as a sample In the electrostatic chuck device of Example 1-2, the temperature variation of the wafer substrate was within ±3° C., which is acceptable.

[0099] <Example 1-3> The electrostatic chuck device of Example 1-3 is based on the electrostatic chuck device described in the above-mentioned <Modification>, and has a configuration in which the protrusion 32 is connected to the center of the base 30. The material of the base 30 is a silicon carbide-aluminum (SiC-Al) composite material with aluminum oxide (Al 2 O 3 The electrostatic chuck plate 10 is made of aluminum oxide (Al 2 O 3 ) and the material of the bonding layer 20 is indium. The bonding surface 31a of the base 30a has a plurality of protrusions 32a having the shape shown in Fig. 10, and the height of the protrusions 32a is 100 [μm].

[0100] 1. Thickness of the bonding layer 20 In the electrostatic chuck device of Example 1-3, the thickness of the bonding layer 20 was within the range of 100±25 [μm], which was acceptable.

[0101] 2. Defects in the bonding layer 20 In the electrostatic chuck device of Example 1-3, it was confirmed that the bonding agent peeled off from the portion connecting the projections 32 in the center.

[0102] 3. Temperature cycle test In the electrostatic chuck device of Example 1-3, it was confirmed that the bonding agent peeled off from the portion connecting the projections 32 in the center.

[0103] 4. Temperature variation when a wafer is heated as a sample In the electrostatic chuck device of Example 1-3, it was confirmed that the center of the wafer substrate was abnormally cooled.

[0104] <Example 1-4> The electrostatic chuck device of Examples 1-4 is based on the electrostatic chuck device described in the above-mentioned Comparative Example, and has a configuration in which concentric projections 132 are formed. The material of the base 30 is a silicon carbide-aluminum (SiC-Al) composite material, and the material of the electrostatic chuck plate 10 is aluminum oxide (Al 2 O 3 ) and the material of the bonding layer 20 is indium. Furthermore, on the bonding surface 31 of the base 30, a plurality of protrusions 132 having a given diameter are concentrically arranged as shown in Fig. 14. The height of the protrusions 32 is 100 [μm].

[0105] 1. Thickness of the bonding layer 20 In the electrostatic chuck device of Example 1-4, the variation in thickness of the bonding layer 20 was 100±50 [μm], which was unacceptable.

[0106] 4. Temperature variation when a wafer is heated as a sample In the electrostatic chuck device of Example 1-4, the temperature variation within the surface of the wafer substrate was ±7° C., which was unacceptable.

[0107] Next, the effects of the electrostatic chuck device of this embodiment and the modified example will be described. The electrostatic chuck device 1 and 1a of this embodiment and the modified example have a plurality of protrusions 32 extending radially from the bonding surface 31 of the base 30 and 30a (hereinafter, collectively referred to as the base 30. The bonding surface 31a and the protrusions 32a are also collectively referred to as the bonding surface 31 and the protrusions 32, respectively). Therefore, the extension direction of the protrusions 32 is along the direction 21 of thermal expansion and thermal contraction of the bonding agent. This makes it possible to relieve stress caused by the difference in the thermal expansion coefficients of the electrostatic chuck plate 10, the bonding layer 20, and the base 30, and to make the thickness of the bonding layer 20 uniform. Therefore, it is possible to make the heat transfer uniform.

[0108] On the other hand, in the electrostatic chuck device of the comparative example, the protrusions 132 have a concentric shape and are not aligned with the direction 21 of thermal expansion and thermal contraction of the bonding agent. Therefore, it is not possible to alleviate the stress caused by the difference in the thermal expansion coefficients of the electrostatic chuck plate 10, the bonding layer 20, and the base 130, and it is not possible to make the thickness of the bonding layer 20 uniform.

[0109] In the electrostatic chuck devices 1 and 1a of the present embodiment and the modified example, a rigid material is used for the base 30, and therefore deformation can be suppressed even if pressure is applied when bonding the electrostatic chuck plate 10 to the base 30. This can improve the accuracy of the thickness of the bonding layer 20 controlled by the protrusions 32. In addition, the protrusions 32 are disposed so as to be embedded in the bonding agent. This allows the stress generated in the bonding agent to be calculated with high accuracy, and the thermal stress can be alleviated.

[0110] The area where the protrusions 32 of the base 30 contact the rear surface 12 of the electrostatic chuck plate 10 is 60% or less of the area of ​​the rear surface 12. Therefore, the bonding layer 20 can have a bonding strength capable of withstanding stress. Also, the heat transfer can be controlled with high precision.

[0111] In addition, the bonding layer 20 can be formed using a bonding agent having a thermal expansion coefficient significantly different from that of the electrostatic chuck plate 10 and the base 30. This allows a wider range of types of bonding agents and temperatures for use, thereby expanding the range of applications.

[0112] The multiple protrusions 32 include multiple protrusions 32p and multiple protrusions 32q that are shorter in length than the protrusions 32p. The end of the protrusion 32q on the central flat portion 33 side is disposed closer to the outer periphery 35 than the end of the protrusion 32p on the central flat portion 33 side. This makes it possible to uniformize the force F generated in the bonding agent.

[0113] In the electrostatic chuck device 1 of the present embodiment, a central flat portion 33 is formed on the bonding surface 31 of the base 30. Therefore, sink marks and defects due to thermal expansion or thermal contraction of the bonding layer 20 can be suppressed.

[0114] Since the holes for passing the wiring of the internal electrodes of the electrostatic chuck plate 10 are formed in the vicinity of the ends of the protrusions 32q on the central flat portion 33 side, the uniformity of the force F acting on the bonding agent is not hindered. In addition, the function of the central flat portion 33 is not hindered.

[0115] (Embodiment 2) Next, an electrostatic chuck device according to a second embodiment will be described. As described above, in the technique for bonding between the electrostatic chuck plate 10 and the base 30 in the electrostatic chuck device, a resin adhesive may be used depending on the application. The adhesive between the electrostatic chuck plate 10 and the base 30 mainly serves to relieve thermal stress between the electrostatic chuck plate 10 and the base 30 and to smoothly transfer heat flowing into a sample adsorbed and fixed to the electrostatic chuck plate 10 to the base 30.

[0116] However, when a resin adhesive is used, the usable temperature range for the electrostatic chuck device is determined by the glass transition point and decomposition point of the resin used (silicone, epoxy, acrylic, etc.), etc. Therefore, the usable temperature range for the electrostatic chuck device is often narrow.

[0117] In addition, resin has a low thermal conductivity to begin with, and this prevents the heat that flows into the sample attracted to the electrostatic chuck plate 10 from being smoothly transferred to the base 30. Therefore, in order to improve the low thermal conductivity, a material with high thermal conductivity is added as a filler. For example, aluminum nitride (AlN) or aluminum oxide (Al 2 O 3 ) filler is added to improve thermal conductivity. The addition of this filler increases the Young's modulus of the cured body, especially in silicone adhesives with a low Young's modulus (elastic modulus), and significantly reduces the ability to relax thermal stress. Also, adding too much filler reduces the handleability of the adhesive, lowering work efficiency.

[0118] Therefore, in this embodiment, a resin bonding agent is used, which has a low glass transition temperature and suppresses the increase in Young's modulus from room temperature to extremely low temperature even if a filler is added. Since resin has a large thermal expansion coefficient, the thermal expansion coefficients of the electrostatic chuck plate 10 and the base 30 are matched to prevent unnecessary thermal stress. In addition, the curing conditions of the bonding agent containing filler are optimized to provide an electrostatic chuck device that can be used in a wide temperature range from room temperature to extremely low temperature. Below, <Example 2-1> to <Example 2-4> using a resin bonding agent will be described.

[0119] <Example 2-1> The electrostatic chuck device of Example 2-1 has a configuration based on the electrostatic chuck device described in the above-mentioned embodiment 1. The materials contained in the base 30, the electrostatic chuck plate 10, and the bonding agent are as follows.

[0120] A. Material ·Base: SiC-Al composite material Electrostatic chuck plate: Aluminum 2 O 3 Bonding agent: Silicone adhesive with nitride filler (4.5 [W / mK])

[0121] B. Manufacturing method In the method for manufacturing an electrostatic chuck device of this embodiment, first, steps S11 and S12 in FIG. 9 are performed in the same manner as in the method for manufacturing an electrostatic chuck device of the above-described first embodiment.

[0122] Next, in step S13, a bonding agent is applied to the electrostatic chuck plate 10 and the base 30, and a degassing process is performed in a vacuum at 50° C. for 30 minutes. Then, the electrostatic chuck plate 10 and the base 30 are bonded together, and a pressure of 6 kPa is applied, and a degassing process is again performed in a vacuum at 50° C. for 30 minutes.

[0123] Next, after releasing to atmospheric pressure, the pressure is increased to 9 kPa and left to stand for 60 min. After that, in this state, the temperature is raised to 90°C and left to stand for 20 h to carry out the hardening process. Then, while still applying pressure, it is cooled to 30°C or less. It is cooled to room temperature and it is confirmed that the bonding agent has hardened.

[0124] C. Evaluation Method Next, the method for evaluating the electrostatic chuck device will be described. A three-dimensional measuring device is used to calculate the deformation from the overall thickness of the electrostatic chuck device. In this Example 2-1, the flatness was found to be within 80 [μm], and it was confirmed that the device passed the test.

[0125] A defect inspection is performed from the electrostatic chuck plate 10 side of the electrostatic chuck device using an ultrasonic flaw detector. If there are no major defects in the bonding layer and the bonding area is 99% or more, it is considered to pass. The electrostatic chuck device is subjected to a temperature cycle test of -150°C to 100°C 30 times. After the temperature cycle test, a defect inspection is performed again using the ultrasonic flaw detector. In this Example 2-1, it was confirmed that there were no major defects in the bonding layer both before and after the temperature cycle test, and it passed.

[0126] The wafer substrate is attracted and fixed to the electrostatic chuck plate 10, and the wafer temperature is measured when a heat input of 5.5 kW is applied in a state cooled to -150°C. In this Example 2-1, the wafer temperature was -135°C, and it was confirmed that the test was acceptable.

[0127] D. Tensile Load Evaluation A special jig is formed by machining. The special jig is bonded in place of the electrostatic chuck plate 10 under the same conditions and with the same work content as in the manufacturing method of the electrostatic chuck device. The sample is then cooled to a predetermined temperature (23°C, -150°C). The cooled sample is attached to a universal testing machine and then pulled up and down. The load when the bonded special jig breaks at the bonding layer 20 is measured.

[0128] <Example 2-2> Next, Example 2-2 will be described. In the electrostatic chuck device of Example 2-2, the materials of the base 30, the electrostatic chuck plate 10, and the bonding agent are as follows.

[0129] A. Material ·Base: SiC-Al composite material Electrostatic chuck plate: Aluminum 2 O 3 Adhesive: Silicone adhesive without filler (0.15[W / mK])

[0130] B. Manufacturing method Same as Example 2-1.

[0131] C. Evaluation Method In this Example 2-2, the flatness was within 80 [μm] or less, and it was confirmed that the test was passed. In this Example 2-2, there was no change in the bonding layer 20 both before and after the temperature cycle test, and it was confirmed that the test was passed. When the wafer substrate was adsorbed and fixed to the electrostatic chuck plate 10 and cooled to -150 [°C], the wafer temperature when a heat input of 5.5 [kW] was applied was -95 [°C], and it was confirmed that the test was passed.

[0132] <Example 2-3> Next, Example 2-3 will be described. In the electrostatic chuck device of Example 2-3, the base 30, the electrostatic chuck plate 10, and the materials contained in the bonding agent are as follows.

[0133] A. Material ·Base: SiC-Al composite material Electrostatic chuck plate: Aluminum 2 O 3 Bonding agent: Silicone adhesive with oxide filler (0.5 [W / mK])

[0134] B. Manufacturing method Same as Example 2-1.

[0135] C. Evaluation Method In this Example 2-3, the flatness was within 80 [μm] or less, and it was confirmed that the test was passed. In this Example 2-3, there was no change in the bonding layer 20 both before and after the temperature cycle test, and it was confirmed that the test was passed. When the wafer substrate was adsorbed and fixed to the electrostatic chuck plate 10 and cooled to -150 [°C], the wafer temperature when a heat input of 5.5 [kW] was applied was -110 [°C], and it was confirmed that the test was passed.

[0136] <Example 2-4> Next, Example 2-4 will be described. In the electrostatic chuck device of Example 2-4, the base 30, the electrostatic chuck plate 10, and the materials contained in the bonding agent are as follows.

[0137] A. Material ·Base: Al material Electrostatic chuck plate: Aluminum 2 O 3 Bonding agent: Silicone adhesive with nitride filler (4.5 [W / mK])

[0138] B. Manufacturing method Same as Example 2-1.

[0139] C. Evaluation Method In this Example 2-4, the flatness was within 90 to 110 [μm] or less, and it was confirmed that the test was acceptable. In this Example 2-4, there was no change in the bonding layer 20 both before and after the temperature cycle test, and it was confirmed that the test was acceptable. When the wafer substrate was adsorbed and fixed to the electrostatic chuck plate 10 and cooled to -150 [°C], the wafer temperature when a heat input of 5.5 [kW] was applied was -135 [°C], and it was confirmed that the test was acceptable.

[0140] Considering these examples, it is preferable that the bonding agent contains a thermosetting resin and has a thermal conductivity of 4.0 [W / (mK)] or more. In the case of a silicone adhesive containing a nitride filler, as shown in Examples 2-1 and 2-4, the thermal conductivity is 4.5 [W / mK], which is highly evaluated.

[0141] The bonding agent preferably has a Young's modulus of 1 GPa or less at -150°C. The rate of change in Young's modulus of the bonding agent when cooled from 23°C to -150°C is preferably less than 500%. The tensile load of the bonding agent when cooled from 23°C to -150°C is preferably less than 12.6 cm. 2 It is preferable that the area ratio is 15 times or less of the area ratio of the above.

[0142] The bonding agent preferably contains at least one of silicone resin, epoxy resin, and acrylic resin. The bonding agent preferably has a decomposition temperature of 260°C or higher. In other words, the bonding agent can be used at temperatures below 260°C without decomposing.

[0143] The bonding agent preferably contains 35[%] to 45[%] of thermally conductive filler. The thermally conductive filler preferably has a particle size D90 of 25[μm] or less and a particle size D50 of less than 10[μm]. It is preferable that 90[%] of the thermally conductive filler has a particle size of 25[μm] or less and 50[%] of the thermally conductive filler has a particle size of less than 10[μm]. In addition, it is preferable that the viscosity of the bonding agent is 10[Pa·s] or less.

[0144] The decomposition temperature of the bonding agent before heat curing is preferably 300°C or higher. The thermally conductive filler contained in the bonding agent is aluminum nitride (AlN), silicon nitride (Si 3 N 4 It is preferable that the insulating layer contains at least one of silicon carbide (SiC), boron nitride, and silicon carbide (SiC).

[0145] Both the electrostatic chuck plate 10 and the base 30 are made of aluminum (Al), yttrium oxide, silicon carbide (SiC), aluminum oxide (Al 2 O 3 It is preferable that the electrostatic chuck plate 10 and the base 30 contain at least one of aluminum nitride (AlN). The difference in thermal expansion between the electrostatic chuck plate 10 and the base 30 is 1×10 -6It is preferable that the temperature is 50° C. or lower.

[0146] Next, the effects of this embodiment will be described. The electrostatic chuck device of this embodiment can be used even in an extremely low temperature range of about -100 [℃]. Specifically, in the electrostatic chuck device, the Young's modulus of the bonding layer 20 does not increase even in an extremely low temperature range. Therefore, the thermal stress of the electrostatic chuck device can be continuously relaxed. In addition, since the thermal stress can be relaxed, excessive deformation during use can be suppressed. Furthermore, since the deformation of the stage on which the sample is placed can be reduced, the temperature of the sample can be controlled uniformly. In addition, since the bonding layer 20 has high thermal conductivity, the transfer of heat of the bonding layer 20 can be improved. Other configurations and effects are included in the description of the first embodiment.

[0147] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention. For example, the configurations of the first and second embodiments and the modified examples can be combined with each other. [Explanation of symbols]

[0148] 1, 1a Electrostatic chuck device 10 Electrostatic chuck plate 11 Adsorption surface 12 Back side 20 Bonding layer 21 directions 30, 30a, 130 base 31, 31a, 131 joint surface 32, 32a, 32p, 32pa, 32q, 32qa, 132 protrusion 32h height 32w width 33 Central flat area 34 Protrusion arrangement part 35 Outer periphery 36 holes

Claims

1. An electrostatic chuck plate; a bonding layer including a bonding agent bonded to a back surface of the electrostatic chuck plate; a base including a bonding surface bonded to the bonding layer, the base having a plurality of protrusions formed thereon, the protrusions extending radially from a center portion of the bonding surface toward an outer periphery thereof; Equipped with The ends of the projections on the central side are spaced apart. Electrostatic chuck device.

2. The joining surface has a flat central flat portion surrounded by the end portions at the central portion.

2. The electrostatic chuck device of claim 1.

3. The plurality of protrusions include A plurality of first protrusions each having a first length in a direction in which the protrusions extend; a plurality of second protrusions having a second length less than the first length; having The end portion of the second protrusion on the central portion side is disposed closer to the outer periphery side than the end portion of the first protrusion on the central portion side.

3. The electrostatic chuck device according to claim 1 or 2.

4. A hole is formed in the joining surface near the end of the second projection on the central portion side.

4. The electrostatic chuck device according to claim 3.

5. An electrostatic chuck plate; a bonding layer including a bonding agent bonded to a back surface of the electrostatic chuck plate; a base including a bonding surface bonded to the bonding layer, the base having a plurality of protrusions formed thereon, the protrusions extending radially from a center portion of the bonding surface toward an outer periphery thereof; Equipped with The plurality of protrusions include A plurality of first protrusions each having a first length in a direction in which the protrusions extend; a plurality of second protrusions having a second length less than the first length; having The end portion of the second protrusion on the central portion side is disposed closer to the outer periphery side than the end portion of the first protrusion on the central portion side. Electrostatic chuck device.

6. A hole is formed in the joining surface near the end of the second projection on the central portion side.

6. The electrostatic chuck device according to claim 5.

7. At least two ends of the first projections on the central portion side are connected to each other.

7. The electrostatic chuck device according to claim 5 or 6.

8. The protrusion is embedded in the bonding agent. The electrostatic chuck device according to any one of claims 1 to 7.

9. The protrusion directly contacts the back surface, The area where the protrusions contact the rear surface is 60% or less of the area of ​​the rear surface. The electrostatic chuck device according to any one of claims 1 to 3 and 5.

10. The base includes a flow path through which a coolant flows. The electrostatic chuck device according to any one of claims 1 to 9.

11. The Young's modulus of the base is 200 [GPa] or more, The difference between the thermal expansion coefficient of the base and the thermal expansion coefficient of the electrostatic chuck plate is 1×10 －６ [ / ℃] or less, The thermal conductivity of the base is 50 [W / (mK)] or more. The electrostatic chuck device according to any one of claims 1 to 10.

12. The base includes at least one of aluminum, a metal matrix composite material, silicon carbide and silicon, aluminum oxide, and aluminum nitride. The electrostatic chuck device according to any one of claims 1 to 11.

13. The electrostatic chuck plate is Including an internal electrode, Contains at least one of yttrium oxide, silicon carbide, aluminum oxide, and aluminum nitride; The electrostatic chuck device according to any one of claims 1 to 12.

14. The bonding agent contains at least one of indium, aluminum, silver, and tin, an alloy containing at least one of indium, aluminum, silver, and tin, or contains at least one of silicone resin, acrylic resin, and epoxy resin. The electrostatic chuck device according to any one of claims 1 to 13.

15. The bonding agent includes a thermosetting resin, The bonding agent has a thermal conductivity of 4.0 [W / (mK)] or more and a Young's modulus of 1 [GPa] or less at -150 [°C]. The electrostatic chuck device according to any one of claims 1 to 13.

16. In the bonding agent, the rate of change in Young's modulus when cooled from 23° C. to −150° C. is less than 500%, and the tensile load when cooled from 23° C. to −150° C. is 12.6 cm ２ ] is 15 times or less per area, 16. The electrostatic chuck apparatus of claim 15.

17. The bonding agent contains at least one of a silicone resin, an epoxy resin, and an acrylic resin, and has a decomposition temperature of 260° C. or higher.

17. The electrostatic chuck device according to claim 15 or 16.

18. The bonding agent contains 35% to 45% of a thermally conductive filler, The thermally conductive filler has a particle size D90 of 25 μm or less and a particle size D50 of less than 10 μm, The viscosity of the bonding agent is 10 [Pa s] or less. The electrostatic chuck device according to any one of claims 15 to 17.

19. The decomposition temperature of the bonding agent before heat curing is 300° C. or higher, The bonding agent includes a thermally conductive filler, The thermally conductive filler has a particle size D90 of 25 μm or less and a particle size D50 of less than 10 μm. The electrostatic chuck device according to any one of claims 15 to 18.

20. The thermally conductive filler includes at least one of aluminum nitride, silicon nitride, boron nitride, and silicon carbide.

20. The electrostatic chuck device according to claim 18 or 19.

21. Both the electrostatic chuck plate and the base include at least one of aluminum, yttrium oxide, silicon carbide, aluminum oxide, and aluminum nitride. The electrostatic chuck device according to any one of claims 15 to 20.

22. The thermal expansion difference between the electrostatic chuck plate and the base is 1×10 at each temperature from 23° C. to −100° C. －６ [ / ℃] or less, The electrostatic chuck device according to any one of claims 15 to 21.

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