JP7633794B2 - Electrostatic Chuck Device - Google Patents

Description

The present invention relates to an electrostatic chuck device.

An electrostatic chuck device includes an electrostatic chuck plate that uses electrostatic force to attract a sample such as a wafer, and a base including a cooling mechanism. When indium or aluminum is used as the adhesive for bonding the electrostatic chuck plate to the base, the thickness of the adhesive layer is controlled by masking tape or wire. Alternatively, the thickness of the adhesive layer may be controlled by the thickness of the applied film, without using any member for controlling the thickness.

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

Patent Document 2 also describes that the thickness of the bonding layer is controlled by the film thickness or foil to which the bonding agent is applied.

JP 2019-104964 A Patent No. 3485390

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.

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

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 lead to variations in the thickness of the bonding layer after bonding, which can easily cause uneven contact heat transfer. In addition, in environments where thermal expansion and contraction occur, the adhesive is prone to breakage. 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.

As such, it is difficult to control the thickness of the bonding layer with high precision when using masking tape or wire.

The method of Patent Document 2 does not have anything that acts 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.

In addition, in the case of resin adhesives, there is also 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 occurs due to load, and it is not possible to apply a sufficient load required for thickness adjustment. When a ceramic plate is used, stress concentration occurs as with wires, which can lead to damage to the electrostatic chuck plate.

The present invention was made in consideration of the above problems, and provides an electrostatic chuck device that can control the thickness of the bonding layer between the electrostatic chuck plate and the base with high precision, and can uniformly cool or heat the sample that is fixed by chucking.

The electrostatic chuck device according to the present invention comprises an electrostatic chuck plate, a bonding layer containing a bonding agent bonded to the back surface of the electrostatic chuck plate, and a base including a bonding surface bonded to the bonding layer and having a plurality of protrusions formed thereon extending radially from the center of the bonding surface toward the outer periphery.

In the electrostatic chuck device, the ends of each protrusion on the central side may be spaced apart.

In the electrostatic chuck device, the joining surface may have a flat central flat portion in the center surrounded by the ends.

In the electrostatic chuck device, the plurality of protrusions may have a plurality of first protrusions having a first length in the direction in which the protrusions extend, and a plurality of second protrusions having a second length that is shorter than the first length, and the end portion on the central side of the second protrusions may be disposed closer to the outer periphery than the end portion on the central side of the first protrusions.

In the electrostatic chuck device, a hole may be formed in the joining surface near the end of the second protrusion on the central side.

In the electrostatic chuck device, the ends of at least two of the protrusions on the central side may be connected.

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

In the electrostatic chuck device, the protrusions may be in direct contact with the rear surface, and the area of the protrusions in contact with the rear surface may be 60% or less of the area of the rear surface.

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

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

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

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

In the electrostatic chuck device, the bonding agent may contain at least one of indium, aluminum, silver, and tin, an alloy containing at least one of indium, aluminum, silver, and tin, or at least one of silicone resin, acrylic resin, and epoxy resin.

The bonding agent may contain 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].

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 may be 15 times or less per 12.6 ^cm2 area.

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

The bonding agent may contain 35% to 45% of a thermally conductive filler, 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, and the viscosity of the bonding agent may be 10 Pa·s or less.

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.

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

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

The difference in thermal expansion between the electrostatic chuck plate and the base may be within 1×10 ⁻⁶ [/° C.] at each temperature range from 23 [° C.] to −100 [° C.].

The present invention provides an electrostatic chuck device that can uniformly cool or heat a sample that is fixed by suction.

1 is a cross-sectional view illustrating an electrostatic chuck device according to a first embodiment. 3 is a plan view illustrating a bonding surface of a base in the electrostatic chuck device according to the first embodiment. FIG. 2 is a perspective view illustrating a bonding surface of a base in the electrostatic chuck device according to the first embodiment. FIG. 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. 3 is a cross-sectional perspective view illustrating a protrusion of a base in the electrostatic chuck device according to the first embodiment. FIG. 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. 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 . 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. FIG. 4 is a flowchart illustrating a method for manufacturing the electrostatic chuck device according to the first embodiment. FIG. 11 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. 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. 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 . 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 . FIG. 11 is a perspective view illustrating a bonding surface of a base in an electrostatic chuck device according to a comparative example.

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

(Embodiment 1)
The electrostatic chuck device according to the first embodiment will be described below. First, the configuration of the electrostatic chuck device will be described. Then, the configurations of the electrostatic chuck plate, bonding layer, and base that constitute the electrostatic chuck device will be described. Then, a manufacturing method of the electrostatic chuck device will be described. Next, a modified example of the first embodiment and a comparative example for comparison with the first embodiment will be described. Then, evaluation of the electrostatic chuck device for the first embodiment, the modified example, and the comparative example will be described as Example 1-1 to Example 1-4.

<Configuration of electrostatic chuck device>
Fig. 1 is a cross-sectional view illustrating an electrostatic chuck device according to the 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.

Here, for the sake of convenience in explaining 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. The 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 the sake of convenience in explaining the electrostatic chuck device 1, and do not indicate the orientation in which the electrostatic chuck device 1 is actually disposed when in use.

<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 to 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.

The electrostatic chuck plate 10 includes an internal electrode (not shown) inside. The electrostatic chuck plate 10 applies a voltage to the internal electrode, and the sample is attracted and fixed to the attraction surface 11 by electrostatic force.

The electrostatic chuck plate 10 includes, for example, ceramics as a material. The electrostatic chuck plate 10 may include, for example, at least one of aluminum oxide (Al ₂ O ₃ ) and aluminum nitride (AlN).

Table 1 is a table illustrating a comparison of material properties. Table 1 below shows the density [kg _{/m 3 ], thermal expansion coefficient [10 −6 /° C.], Young's modulus [GPa], Poisson's ratio, and thermal conductivity [W/(mK)] of aluminum oxide (Al 2 O 3} ^{) ,} metal matrix composite material (Metal Matrix Composites, hereinafter referred to as MMC), aluminum nitride (AlN), silicon carbide (SiC), indium (Indium), and silicone resin (Silicone).

As shown in Table 1, when the material of the electrostatic chuck plate 10 is aluminum oxide (Al ₂ O ₃ ) and the material of the base 30 is metal matrix composite material (MMC), the difference in thermal expansion coefficient between the electrostatic chuck plate 10 and the base 30 can be made 1×10 ⁻⁶ [/° C.] or less. 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 made 1×10 ⁻⁶ [/° C.] or less. By using such materials, the stress generated between the electrostatic chuck plate 10 and the base 30 can be alleviated.

<Bonding 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.

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 base 30 differ greatly from the bonding agent, but in the electrostatic chuck device 1 of this embodiment, the protrusions 32 of the base 30 described below can reduce the effect of the difference in thermal expansion coefficients.

If the pore content of the bonding agent constituting the bonding layer 20 is taken as the porosity, the porosity of the bonding agent is preferably 5% or less. This improves the thermal conductivity and heat transfer coefficient between the electrostatic chuck plate 10 and the base 30, and suppresses damage due to thermal expansion and thermal contraction.

<Foundation>
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 referred to as a bonding surface 31. Thus, the base 30 includes the bonding surface 31 bonded to the bonding layer 20.

The base 30 preferably contains a material having rigidity. For example, the base 30 may contain 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 thermal expansion coefficient between the electrostatic chuck plate 10 and the base 30 can be set to 1×10 ⁻⁶ [/° C.] or less.

The base 30 desirably contains a material with 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 the 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.

In addition, the thermal conductivity of the base 30 is preferably 50 [W/(mK)] or more. This improves the heat transfer from the base 30 to the electrostatic chuck plate 10 via the bonding layer 20.

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

As shown in Figures 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 central side of each protrusion 32 is disposed at a distance from the end portion on the central side of the adjacent protrusion 32. Thus, the joint surface 31 has a flat central flat portion 33 in the center surrounded by the ends on the central side of each protrusion 32.

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 peripheral portion 35 formed in an annular shape so as to surround the protrusion arrangement portion 34. The multiple protrusions 32 are formed on the protrusion arrangement portion 34.

As shown in FIG. 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.

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

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

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 back surface 12 of the electrostatic chuck plate 10. The area of the protrusions 32 in contact with the back surface 12 of the electrostatic chuck plate 10 is preferably 60% or less of the area of the back surface 12. This can improve the heat transfer coefficient between the electrostatic chuck plate 10 and the base 30. In addition, damage due to thermal expansion and thermal contraction of the bonding agent can be suppressed.

The base 30 may include a flow path (not shown) through which the refrigerant 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.

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

As shown in Figures 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, since the direction in which the protrusions 32 extend and the direction 21 in which the bonding agent thermally contracts are the same, the stress generated between the electrostatic chuck plate 10 and the base 30 and the bonding layer 20 can be alleviated. Note that 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 in use.

In addition, a central flat portion 33 is formed on the bonding surface 31 of the base 30. The central flat portion 33 allows the expansion and contraction of the bonding agent to be adjusted. This allows the bonding agent to freely deform during thermal contraction when cooled during the manufacturing process, and during thermal expansion and contraction when heated and cooled during use. This makes it possible to suppress sink marks and defects caused by thermal expansion or thermal contraction of the bonding layer 20.

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, if the thickness of the bonding layer 20 is small, the pitch of the protrusions 32 is increased. This results in a bonding layer 20 containing a bonding agent that is flat in the horizontal direction. On the other hand, if the thickness of the bonding layer 20 is large, the pitch of the protrusions 32 is decreased. 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.

Figure 8 is a diagram illustrating a model for calculating the stress generated in the bonding agent arranged 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 Figure 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.

σ = −αΔT E (1)
F=-αΔTEA (2)

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

As shown in Table 2, assuming that the thermal expansion coefficient α is 30×10 ^-6 [/°C], Young's modulus E is 11.5 [GPa], and temperature difference ΔT is -250 [°C], 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. A positive value for the force F indicates a tensile load, and a negative value for the force F indicates a compressive load.

Table 3 shows an example of the cross-sectional area A of the bonding agent placed between the protrusions 32 and the force F generated in the electrostatic chuck device 1 according to embodiment 1.

As shown in Table 3, the larger the cross-sectional area A of the bonding agent, the greater the force F generated in the bonding agent. For example, if the height H of the bonding agent is constant, the greater the width W of the bonding agent, the greater the force F. Also, if the width W of the bonding agent is constant, the greater the height H of the bonding agent, the greater 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.

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. In other words, the width W of the bonding agent becomes larger toward the outer periphery 50. Therefore, the multiple protrusions 32 have multiple protrusions 32p and multiple protrusions 32q whose length is shorter than that of protrusions 32p. The end of protrusion 32q on the central flat portion 33 side is positioned closer to the outer periphery 35 than the end of 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.

<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 serves as 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.

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

It may be considered acceptable to form the protrusions 32 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.

The arrangement of the protrusions 32 can be varied to match the thickness of the bonding layer 20. For example, the pitch of the protrusions 32 may be varied 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 wide when the bonding layer 20 is thin.

For insulating the base 30, a film of aluminum oxide (Al ₂ O ₃ ) may be formed on the surface of the base 30 by thermal spraying. In this case, similar protrusions 32 may be formed on the thermal sprayed film.

Next, as shown in step S13, the electrostatic chuck plate 10 and the base 30 are bonded via a bonding layer. For example, 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. Note that no load is necessary, but 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. After that, 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.

<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.

Figure 10 is a perspective view illustrating the joint surface 31a of the base 30a in an electrostatic chuck device according to a modified example of embodiment 1. As shown in Figure 10, in the electrostatic chuck device of this modified example, 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 whose length is shorter than the length of the protrusions 32pa, as in embodiment 1. However, the joint surface 31a of the base 30a of the modified example does not have a central flat portion 33. The ends of the multiple protrusions 32pa on the central side are connected to each other at the center.

Figure 11 is a plan view illustrating the thermal contraction process of the bonding agent during cooling in an electrostatic chuck device according to a modified example of embodiment 1. Figures 12 and 13 are cross-sectional views illustrating the thermal contraction process of the bonding agent during cooling in an electrostatic chuck device according to a modified example of embodiment 1, showing a cross section taken along line XII-XII in Figure 11.

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.

On the other hand, in this modified example, the central flat portion 33 is not formed on the joining 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 joining surface 31a. For example, the adhesive peels off from the portion where the central protrusions 32a are connected.

Specifically, as shown in FIG. 12, in the modified electrostatic chuck device 1a, the bonding agent is filled between the electrostatic chuck plate 10 and the base 30a during the curing process. Then, as shown in FIG. 13, the bonding agent near the center peels off due to contraction after curing. Thus, in this modified example, the electrostatic chuck plate 10 and the base 30a have different thermal expansion coefficients from the bonding agent, so the bonding agent expands and contracts on the side of the central protrusion 32a. Therefore, the stress resistance of the central bonding layer 20 is reduced, and the bonding agent is more likely to peel off around the central protrusion 32a.

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 protrusions 132 are formed on the bonding surface 131 of the base 130. The protrusions 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.

<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.

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. For the temperature cycle test, a temperature cycle test from -100°C to 100°C is performed 30 times on the electrostatic chuck device, and after the test, a defect inspection is again performed using an ultrasonic flaw detector. 4. For the temperature variation when the wafer is heated as a sample, the temperature variation of the wafer substrate is measured when a heat input of 3 kW is applied while the wafer substrate is adsorbed and fixed to the electrostatic chuck plate 10.

<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 center of 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, 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. In addition, the bonding surface 31 of the base 30 has a plurality of protrusions 32 having the shapes shown in Figures 2 to 5, and the height of the protrusions 32 is 100 [μm].

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.

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.

3. Temperature Cycle Test With the electrostatic chuck device of Example 1-1, there was no change in the defect inspection results before and after the temperature cycle test, and the test was passed.

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 is within ±3° C., which is acceptable.

<Example 1-2>
The electrostatic chuck device of Example 1-2 is based on the electrostatic chuck device described in the above (Embodiment 1), and has a configuration in which the center of 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 a thermally sprayed film of aluminum oxide (Al ₂ O ₃ ), and the material of the electrostatic chuck plate 10 is aluminum nitride (AlN). In addition, the bonding surface 31 of the base 30 has a plurality of protrusions 32 having the shapes shown in Figures 2 to 5, and the height of the protrusions 32 is 100 [μm].

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.

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.

3. Temperature Cycle Test With the electrostatic chuck device of Example 1-2, there was no change in the defect inspection results before and after the temperature cycle test, and the test was passed.

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 is within ±3° C., which is acceptable.

<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 protrusions 32 are connected to the center of the base 30. The material of the base 30 is a silicon carbide-aluminum (SiC-Al) composite material on which an aluminum oxide (Al ₂ O ₃ ) sprayed film is formed, 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. In addition, 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.

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.

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 protrusions 32 in the center.

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 central projections 32.

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.

<Example 1-4>
The electrostatic chuck device of Example 1-4 is based on the electrostatic chuck device described in the above-mentioned Comparative Example, and has a configuration in which concentric protrusions 132 are formed. The material of the base 30 is a silicon carbide-aluminum (SiC-Al) composite material, 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. In addition, as shown in FIG. 14, a plurality of protrusions 132 having a given diameter are concentrically arranged on the bonding surface 31 of the base 30. The height of the protrusions 32 is 100 μm.

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.

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 is unacceptable.

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 direction in which the protrusions 32 extend is along the direction 21 of thermal expansion and thermal contraction of the bonding agent. This makes it possible to alleviate 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.

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.

The electrostatic chuck devices 1 and 1a of this embodiment and the modified example use a rigid material for the base 30, so deformation can be suppressed even when pressure is applied when bonding the electrostatic chuck plate 10 to the base 30. This improves the accuracy of the thickness of the bonding layer 20 controlled by the protrusions 32. In addition, the protrusions 32 are arranged 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 thermal stress can be alleviated.

The area where the protrusions 32 of the base 30 contact the back surface 12 of the electrostatic chuck plate 10 is 60% or less of the area of the back surface 12. Therefore, the bonding layer 20 has a bonding strength that can withstand stress. In addition, heat transfer can be controlled with high precision.

In addition, the bonding layer 20 can be formed using a bonding agent that has a significantly different thermal expansion coefficient from the electrostatic chuck plate 10 and the base 30. This allows a wider range of bonding agent types and operating temperatures, and a wider range of application options.

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 positioned 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 uniformize the force F generated in the bonding agent.

In the electrostatic chuck device 1 of this embodiment, a central flat portion 33 is formed on the bonding surface 31 of the base 30. This makes it possible to suppress sink marks and defects due to thermal expansion or thermal contraction of the bonding layer 20.

The holes for passing the wiring of the internal electrode of the electrostatic chuck plate 10 are formed near the end of the central flat portion 33 side of the protrusion 32q, so they do not impede the uniformity of the force F generated in the bonding agent. In addition, they do not impede the function of the central flat portion 33.

(Embodiment 2)
Next, an electrostatic chuck device according to embodiment 2 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.

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

In addition, resin has a low thermal conductivity to begin with, and this prevents the heat that flows into the sample adsorbed on 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, fillers such as aluminum nitride (AlN) and aluminum oxide (Al ₂ O ₃ ) are added to improve the thermal conductivity. Due to the effect of adding this filler, the Young's modulus of the cured body increases, particularly in silicone bonding agents with a low Young's modulus (elastic modulus), and the thermal stress relaxation ability is significantly reduced. Also, if too much filler is added, the handling property of the bonding agent decreases, and the work efficiency decreases.

Therefore, in this embodiment, a resin bonding agent is used that has a low glass transition temperature and suppresses the increase in Young's modulus from room temperature to the cryogenic temperature range even when 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, by optimizing the curing conditions of the bonding agent containing filler, an electrostatic chuck device is provided that can be used in a wide temperature range from room temperature to the cryogenic temperature range. Below, we will explain <Example 2-1> to <Example 2-4>, which use a resin bonding agent.

<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.

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

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

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. The electrostatic chuck plate 10 and the base 30 are then bonded together, a pressure of 6 kPa is applied, and a degassing process is again performed in a vacuum at 50°C for 30 minutes.

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, the material is cooled to 30°C or less. It is cooled to room temperature and it is confirmed that the bonding agent has hardened.

C. Evaluation Method Next, the evaluation method of 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, it was confirmed that the flatness was within 80 [μm] and passed the test.

A defect inspection is carried out using an ultrasonic flaw detector from the electrostatic chuck plate 10 side of the electrostatic chuck device. 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 carried out 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 that it passed.

The wafer substrate is fixed to the electrostatic chuck plate 10 by suction, cooled to -150°C, and the wafer temperature is measured when a heat input of 5.5 kW is applied. In this Example 2-1, the wafer temperature was -135°C, which was confirmed to be acceptable.

D. Tensile Load Evaluation A dedicated jig is formed by machining. The dedicated jig is bonded in place of the electrostatic chuck plate 10 under the same conditions and 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 dedicated jig breaks at the bonding layer 20 is measured.

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

A. Materials: Base: SiC-Al composite material; Electrostatic chuck plate: Al ₂ O ₃
Bonding agent: filler-free silicone adhesive (0.15 [W/mK])

B. Manufacturing Method The same as in Example 2-1.

C. Evaluation method In this Example 2-2, the flatness was confirmed to be within 80 [μm] and thus passed the test. In this Example 2-2, there was no change in the bonding layer 20 both before and after the temperature cycle test and thus passed the test. 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 thus passed the test.

<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.

A. Materials: Base: SiC-Al composite material; Electrostatic chuck plate: Al ₂ O ₃
Bonding agent: Silicone adhesive containing oxide filler (0.5 [W/mK])

B. Manufacturing Method The same as in Example 2-1.

C. Evaluation method In this Example 2-3, the flatness was within 80 [μm] or less, and it was confirmed that the test was acceptable. 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 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 -110 [°C], and it was confirmed that the test was acceptable.

<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.

A. Materials: Base: Al material; _{Electrostatic} chuck plate: _Al2O3
Bonding agent: Silicone adhesive with nitride filler (4.5 [W/mK])

B. Manufacturing Method The same as in Example 2-1.

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.

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

The bonding agent preferably has a Young's modulus of 1 GPa or less at -150°C. The bonding agent preferably has a change in Young's modulus of less than 500% when cooled from 23°C to -150°C. The bonding agent preferably has a tensile load of 15 times or less per 12.6 ^cm2 area when cooled from 23°C to -150°C.

It is preferable that the bonding agent contains at least one of silicone resin, epoxy resin, and acrylic resin. It is also preferable that the bonding agent 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.

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, the viscosity of the bonding agent is preferably 10 Pa·s or less.

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 preferably includes at least one of aluminum nitride (AlN), silicon nitride (Si ₃ N ₄ ), boron nitride, and silicon carbide (SiC).

Both the electrostatic chuck plate 10 and the base 30 preferably contain at least one of aluminum (Al), yttrium oxide, silicon carbide (SiC), aluminum oxide (Al ₂ O ₃ ), and aluminum nitride (AlN). The difference in thermal expansion between the electrostatic chuck plate 10 and the base 30 is preferably 1×10 ⁻⁶ [/°C] or less at each temperature from 23 [°C] to −100 [°C].

Next, the effects of this embodiment will be described. The electrostatic chuck device of this embodiment can be used even in the cryogenic temperature range of about -100°C. Specifically, in the electrostatic chuck device, the Young's modulus of the bonding layer 20 does not increase even in the cryogenic temperature range. Therefore, the thermal stress of the electrostatic chuck device can be continuously alleviated. In addition, since the thermal stress can be alleviated, 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 can be improved. Other configurations and effects are included in the description of embodiment 1.

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

Reference Signs List 1, 1a Electrostatic chuck device 10 Electrostatic chuck plate 11 Adsorption surface 12 Back surface 20 Bonding layer 21 Direction 30, 30a, 130 Base 31, 31a, 131 Bonding surface 32, 32a, 32p, 32pa, 32q, 32qa, 132 Protrusion 32h Height 32w Width 33 Central flat portion 34 Protrusion arrangement portion 35 Outer periphery 36 Hole

Claims (22)

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. 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 . 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 . 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 . 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. 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. 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 . The protrusion is embedded in the bonding agent.
The electrostatic chuck device according to any one of claims 1 to 7 . 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 . The base includes a flow path through which a coolant flows.
The electrostatic chuck device according to any one of claims 1 to 9 . The Young's modulus of the base is 200 [GPa] or more,
a difference between a thermal expansion coefficient of the base and a thermal expansion coefficient of the electrostatic chuck plate is within 1×10 ⁻⁶ [/° C.];
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 . 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 . 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 . 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 . 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 . 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 15 times or less per 12.6 ^cm2 area.
16. The electrostatic chuck apparatus of claim 15 . 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 . 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 . 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 . 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 . 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 . a thermal expansion difference between the electrostatic chuck plate and the base is within 1×10 ⁻⁶ [/°C] at each temperature from 23 [°C] to −100 [°C];
The electrostatic chuck device according to any one of claims 15 to 21 .

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