Holding device

Abstract

To provide a holding device which can be improved in property of drawing heat away from a to-be-held object.SOLUTION: An electrostatic chuck 1 is provided, comprising a plate-shaped member 10 (10a, 10b), a base member 20, and a joining layer 30 joining the plate-shaped member 10 and the base member 20. The plate-shaped member 10 has a first region R1 at the center in the plane direction and a second region R2 at the periphery in the plane direction. The joining layer 30 has a first joining layer 30a arranged between the base member 20 and the first region R1, and a second joining layer 30b arranged between the base member 20 and the second region R2. The thermal conductivity of the first joining layer 30a is greater than the thermal conductivity of the second joining layer 30b. The Young's modulus of the first joining layer 30a is greater than the Young's modulus of the second joining layer 30b.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a holding device for holding an object.

Background Art

[0002] In semiconductor manufacturing processes, electrostatic chucks (holding devices) are used to hold semiconductor wafers. As such an electrostatic chuck, a ceramic substrate (plate-like member) that holds an object on a mounting surface (holding surface) and a base (base member) joined to the ceramic substrate via a bonding layer are widely known. And, in order to make the temperature distribution on the mounting surface uniform, for example, in what is described in Patent Document 1, the bonding layer is divided into a central portion and its outer peripheral portion, and the thermal conductivity of the bonding layer (second bonding material) in the outer peripheral portion is made higher than the thermal conductivity of the bonding layer (first bonding material) in the central portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described electrostatic chuck, since the thermal conductivity of the bonding layer in the central portion is lower than the thermal conductivity of the bonding layer in the outer peripheral portion, heat transfer in the central portion becomes worse than heat transfer in the outer peripheral portion. Therefore, at the central portion of the object being held, heat transfer (heat extraction) from the object to the base (base member) becomes poor, and the temperature of the object cannot be efficiently lowered. ​There is that. That is, there is a risk that the heat dissipation property from the object to be held will deteriorate.

[0005] And in recent years, a high voltage has been applied to the electrostatic chuck (used at high power). This is increasing. Therefore, the temperature of the object to be held becomes higher than before. The higher the temperature of the object, the lower the efficiency of the process treatment for the object. Therefore, there is a demand for heat dissipation property (improvement of heat dissipation property) that can lower the temperature of the object in a short time.

[0006] Therefore, the present disclosure has been made to solve the above-described problems, and an object thereof is to provide a holding device capable of improving the heat dissipation property from the object to be held.

Means for Solving the Problems

[0007] One aspect of the present disclosure made to solve the above problems is a holding device including a plate-like member, a base member, and a bonding layer that bonds the plate-like member and the base member, wherein the plate-like member has a first region at the central portion in the plane direction and a second region at the outer peripheral portion in the plane direction, the bonding layer has a first bonding layer disposed between the first region and the base member and a second bonding layer disposed between the second region and the base member, the thermal conductivity of the first bonding layer is greater than the thermal conductivity of the second bonding layer, and the Young's modulus of the first bonding layer is greater than the Young's modulus of the second bonding layer.

[0008] In this holding device, the thermal conductivity of the first bonding layer is made greater than the thermal conductivity of the second bonding layer. Thereby, the heat between the plate-like member and the base member in the first region via the first bonding layer ​​​Movement can be promoted. Therefore, from the object to be held to the plate-like member and the base member Since heat transfer is efficiently performed, the heat extraction property from the object to be held can be improved .

[0009] Also, by making the Young's modulus of the first bonding layer larger than that of the second bonding layer, in the outer peripheral portion where the thermal deformation of the base member tends to be large, the thermal expansion difference between the plate-like member and the base member can be firmly absorbed by the second bonding layer. Therefore, when thermal deformation occurs in the holding device, in the outer peripheral portion where poor bonding between the base member and the plate-like member is likely to occur, the second bonding layer can prevent the occurrence of poor bonding between the base member and the plate-like member .

[0010] In the holding device described above It is preferable that the first bonding layer is formed separately from the second bonding layer

[0011] In this way, since the first bonding layer and the second bonding layer are separated in the bonding layer, the arrangement positions of the first bonding layer and the second bonding layer can be freely adjusted in the thickness direction . Thereby, the thicknesses of the plate-like members in the first region and the second region can be controlled independently , so that the heat extraction property from the object to be held can be further improved. Also , the balance of heat transfer in the first region and the second region can be adjusted .

[0012] Also, in any of the holding devices described above It is preferable that the first bonding layer is formed of a bonding material mainly composed of a metal material

[0013] In this way, by forming the first bonding layer of a bonding material mainly composed of a metal material, the first ​​Heat transfer between the plate-like member and the base member in the field can be further promoted. Therefore, since heat transfer from the object to be held to the plate-like member and the base member is performed more efficiently, the heat extraction performance from the object to be held can be further improved.

[0014] Also, in any of the holding devices described above, the plate-like member is formed of ceramics, and it is preferable that the base member is formed of ceramics or a metal-ceramics composite material. That is.

[0015] By forming the base member of ceramics or a metal-ceramics composite material in this way, the difference in thermal expansion coefficient between the plate-like member and the base member can be reduced. Therefore, even when a metal bonding material is used, the plate-like member and the base member can be firmly joined. Therefore, even when the plate-like member and the base member are joined using a metal bonding material, no joint failure occurs. As a result, heat transfer from the object to be held to the plate-like member and the base member is efficiently performed, and the heat extraction performance from the object to be held can be improved. Also, when the plate-like member and the base member are joined using a resin bonding material, the thickness of the joint layer can be made thinner. Therefore, compared with the conventional device, heat transfer from the object to be held to the plate-like member and the base member is promoted, and the heat extraction performance from the object to be held can be improved.

[0016] Also, in any of the holding devices described above, it is preferable that the thickness of the first joint layer is equal to or less than the thickness of the second joint layer.

[0017] Also, in any of the holding devices described above,

[0018] ​​​​​When the thickness of the bonding layer is thin, heat dissipation is improved, and when the thickness is thick, stress relaxation is achieved. Therefore, by making the thickness of the first bonding layer equal to or less than the thickness of the second bonding layer, the inside ( The first bonding layer) can improve heat dissipation, while the outer layer (second bonding layer) It is possible to absorb the difference in expansion. Therefore, the inside of the bonding layer (first bonding layer) improves heat dissipation. The effect of this type of bonding layer is that the outer (second bonding layer) absorbs the thermal expansion difference. This can be further improved by controlling the thickness.

[0019] In addition, in any of the above-mentioned holding devices, a connection electrode is formed on a surface of the base member, The connection electrode is preferably electrically connected to the first bonding layer.

[0020] In this way, by forming the connection electrodes on the surface of the base member, Since the first bonding layer can be used as a high-frequency electrode, the internal electrode provided in the plate-shaped member can be used. This reduces the number of poles in the plate-shaped portion of the area (first area) where the object is placed. Since the thickness of the material can be reduced, the heat dissipation performance can be further improved. Since there is no need to provide a through hole for arranging the connection terminal in the base member, the object can be easily secured. It is also possible to improve the temperature uniformity on the holding surface.

[0021] In order to ensure the insulation of the connection electrodes, the connection electrodes are covered with insulating material formed by thermal spraying or the like. It may be covered with a film.

[0022] In addition, in any of the above-mentioned holding devices, The base member is formed by stacking a plurality of members, It is preferable that the materials of the plurality of members are different.

[0023] Thus, by forming the base member by laminating a plurality of members, a member having a small difference in coefficient of thermal expansion from the plate-like member and a high thermal conductivity (for example, a metal ceramics composite material, etc.) is used for the portion on the surface side that contacts the plate-like member, and a member different from the portion on the surface side that contacts the plate-like member (for example, ceramics, etc.) can be used for the opposite portion. With such a configuration, in addition to being able to improve the heat extraction performance of the plate-like member, the ability to prevent the generation of foreign matter from the through holes (for example, lift pin holes, gas holes, etc.) of the base member

[0024] can be improved. As a result, contamination in the chamber of the semiconductor manufacturing apparatus using the holding device can be prevented. And, since the materials of the plurality of members are different, members formed of different materials can be used for the portion on the surface side that contacts the plate-like member and the opposite portion. Therefore, by using a member having good workability or an inexpensive material for the portion opposite to the surface side that contacts the plate-like member, the productivity (workability) of the holding device can be improved and the manufacturing cost can be reduced.

[0025] Another aspect of the present disclosure made to solve the above problems is a holding device including a plate-like member, a base member, and a bonding layer that bonds the plate-like member and the base member, wherein the plate-like member has a first region at the central portion in the plane direction and a second region at the outer peripheral portion in the plane direction, the bonding layer has a first bonding layer disposed between the first region and the base member, and a second bonding layer disposed between the second region and the base member.

[0026] In the holding device, the plate-like member has a first region at the central portion in the plane direction and a second region at the outer peripheral portion in the plane direction, the bonding layer has a first bonding layer disposed between the first region and the base member, and a second bonding layer disposed between the second region and the base member. The bonding layer has a first bonding layer disposed between the first region and the base member, and a second bonding layer disposed between the second region and the base member. The first bonding layer is formed separately from the second bonding layer. The first bonding layer is characterized by being formed of a bonding material mainly composed of a metal material. .

[0027] In this holding device, since the first bonding layer is formed of a metal bonding material, heat transfer between the plate-like member and the base member in the first region can be promoted. Therefore, heat transfer from the object to be held to the plate-like member and the base member is efficiently performed, so that the heat extraction performance from the object to be held can be improved. Also, since the holding device has the first bonding layer and the second bonding layer formed separately from each other, the arrangement positions of the first bonding layer and the second bonding layer can be freely adjusted in the thickness direction. Therefore, the thickness of the plate-like member in the first region can be reduced, so that the heat extraction performance from the object to be held can be further improved. Furthermore, the balance of heat transfer in each of the first region and the second region can also be adjusted.

[0028]

Advantages of the Invention

[0029] According to the present disclosure, it is possible to provide a holding device capable of improving the heat extraction performance from an object to be held.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0031] A holding device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In this embodiment, the holding device is, for example, an etching device (such as a plasma etching device). semiconductor manufacturing equipment such as deposition equipment (CVD deposition equipment, sputtering deposition equipment, etc.) An electrostatic chuck used in the device will be described as an example.

[0032] Therefore, the electrostatic chuck 1 of this embodiment will be described with reference to FIGS. 1 and 2. The electrostatic chuck 1 of this embodiment is a device that attracts and holds a semiconductor wafer W by electrostatic attraction. For example, the device is used to fix a semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing device. As shown in FIGS. 1 and 2, the electrostatic chuck 1 comprises a plate-shaped member 10 and a base member. The plate-shaped member has a base member and a bonding layer that bonds the plate-shaped member and the base member.

[0033] In the following description, for convenience of explanation, the X, Y, and Z axes are defined as shown in FIG. The Z axis is the axis in the axial direction of the electrostatic chuck 1 (the vertical direction in FIG. 1), and the X axis and the Y axis is the radial axis of the electrostatic chuck 1. The direction of the XY plane is the "plane direction" of the present disclosure. Here is an example.

[0034] As shown in FIG. 1, the plate-shaped member 10 is a disk-shaped member made of ceramics. Specifically, the plate-like member 10 has a first region R1 at the center in the XY plane direction (surface direction). and an outer peripheral portion 10b located in a second region R2 in the XY plane direction (surface direction). The plate-shaped member 10 has a side portion 10b and a central portion that is convex. The semiconductor wafer W is placed on the upper surface 11a of the outer portion 1a (first region R1) of the plate-like member 10. An annular member (focus ring FR) surrounding the semiconductor wafer W is disposed on the upper surface 11b of 0b (the second region R2).

[0035] Various ceramics are used as the ceramics forming the plate-like member 10. From the viewpoints of strength, wear resistance, plasma resistance, etc., for example, ceramics mainly composed of aluminum oxide (alumina, Al2O3) or aluminum nitride (AlN) are preferably used. Here, the main component means the component with the highest content ratio (for example, a component with a volume content ratio of 90 vol% or more).

[0036] As shown in FIGS. 1 and 2, the inner portion 10a of the plate-like member 10 is disk-shaped and has an upper surface 11a which is a holding surface for holding the semiconductor wafer W and a lower surface 12a provided on the side opposite to the upper surface 11a in the Z-axis direction. The diameter of the inner portion 10a is, for example, about 150 mm to 300 mm. Also, the thickness of the inner portion 10a is, for example, about 1 mm to 10 mm. The thermal conductivity of the inner portion 10a is desirably in the range of 10 W / mK to 50 W / mK (more preferably, 18 W / mK to 33 W / mK).

[0037] As shown in FIG. 2, the inner portion 10a of such a plate-like member 10 is provided with a chuck electrode 50 inside thereof. The chuck electrode 50 has, for example, a substantially circular shape when viewed in the Z-axis direction and is formed of a conductive material (for example, tungsten, molybdenum, etc.). A power supply terminal 63 electrically connected to an external power supply (not shown) is electrically connected to the chuck electrode 50 via a via 61 and a terminal pad 62 that are electrically connected thereto. Note that the via 61 and the terminal ​​​​​​​​​​​​​​The pad 62 is formed of a conductive material (e.g., tungsten, molybdenum, etc.). When a voltage is applied to the chuck electrode 50 from an external power source via the power supply terminal 63, the terminal pad 62, and the via 61, an electrostatic attraction force (adsorption force) is generated, and the semiconductor wafer W is adsorbed and fixed to the upper surface 11a by this electrostatic attraction force.

[0038] As shown in FIGS. 1 and 2, the outer portion 10b of the plate-like member 10 is annular and includes an upper surface 11b on which the focus ring FR is disposed and a lower surface 12b provided on the side opposite to the upper surface 11b in the Z-axis direction. The outer diameter of the outer portion 10b is, for example, about 180 mm to 400 mm. Also, the thickness of the outer portion 10b is, for example, about 1 mm to 10 mm. The thermal conductivity of the outer portion 10b is desirably in the range of 10 W / mK to 50 W / mK (more preferably, 18 W / mK to 33 W / mK).

[0039] As shown in FIG. 2, the outer portion 10b of such a plate-like member 10 includes a chuck electrode 51 therein. The chuck electrode 51 has, for example, a substantially annular shape when viewed in the Z-axis direction and is formed of a conductive material (e.g., tungsten, molybdenum, etc.). A power supply terminal 66 connected to an external power source (not shown) is electrically connected to the chuck electrode 51 via a via 64 and a terminal pad 65 that are electrically connected thereto. When a voltage is applied to the chuck electrode 51 from an external power source via the power supply terminal 66, the terminal pad 65, and the via 64, an electrostatic attraction force (adsorption force) is generated, and the focus ring FR is adsorbed and fixed to the upper surface 11b by this electrostatic attraction force.

[0040] ​​​​​​​​​In addition, the outer portion 10b of the plate-like member 10 is provided with a high-frequency electrode 52 inside thereof. The high-frequency electrode 52 has, for example, a substantially annular shape when viewed in the Z-axis direction, and is formed of a conductive material (for example, tungsten, molybdenum, etc.). A power supply terminal 69 that is electrically connected to an external power supply (not shown) is electrically connected to this high-frequency electrode 52 via a via 67 and a terminal pad 68 that are electrically continuous. Note that the vias 64, 67 and the terminal pads 65, 68 are formed of a conductive material (for example, tungsten, molybdenum, etc.).

[0041] As shown in FIG. 1, the base member 20 is disposed on the lower surface side of the plate-like member 10. This base member 20 is formed, for example, in a columnar shape, and in this embodiment, the portion joined to the first region R1 (inner portion 10a) of the plate-like member 10 is convex. Such a base member 20 is formed of, for example, ceramics (for example, SiC, etc.) or a metal-ceramics composite material (Ti / SiC composite material, MMC (Al / SiC composite material), etc.). Thereby, the difference in the coefficient of thermal expansion between the base member 20 and the plate-like member 10 can be reduced.

[0042] Then, as shown in FIGS. 1 and 2, the base member 20 includes an upper surface 21a to which the inner portion 10a of the plate-like member 10 is joined and an upper surface 21b to which the outer portion 10b of the plate-like member 10 is joined, and a lower surface 22 provided on the opposite side of the upper surfaces 21a and 21b in the Z-axis direction. The upper surfaces 21a and 21b of the base member 20 are thermally connected to the lower surface 12a of the inner portion 10a of the plate-like member 10 and the lower surface 12b of the outer portion 10b of the plate-like member 10 via a bonding layer 30 (30a, 30b ).

[0043] The diameter of the base member 20 is, for example, about 180 mm to 400 mm. Also, the thickness (dimension in the Z-axis direction) of the base member 20 is, for example, about 20 mm to 50 mm. Note that the thermal conductivity of the base member 20 (assuming ceramics or MMC) is desirably within the range of 30 W / mK to 200 W / mK (preferably about 100 W / mK). For such a base member 20, a refrigerant flow path 23 for flowing a refrigerant (for example, a fluorine-based inert liquid, water, etc.) is formed. By flowing the refrigerant in this refrigerant flow path 23, the base member 20 is cooled, and the plate-shaped member 10 is cooled through the bonding layer 30. Thus, the semiconductor wafer W whose temperature has risen during various processings is cooled, and heat removal (heat extraction) from the semiconductor wafer W is performed. The thermal conductivity of the base member 20 (assuming ceramics or MMC) is desirably within the range of 30 W / mK to 200 W / mK (preferably about 100 W / mK). For such a base member 20, a refrigerant flow path 23 for flowing a refrigerant (for example, a fluorine-based inert liquid, water, etc.) is formed. By flowing the refrigerant in this refrigerant flow path 23, the base member 20 is cooled, and the plate-shaped member 10 is cooled through the bonding layer 30. Thus, the semiconductor wafer W whose temperature has risen during various processings is cooled, and heat removal (heat extraction) from the semiconductor wafer W is performed.

[0044] For such a base member 20, a refrigerant flow path 23 for flowing a refrigerant (for example, a fluorine-based inert liquid, water, etc.) is formed. By flowing the refrigerant in this refrigerant flow path 23, the base member 20 is cooled, and the plate-shaped member 10 is cooled through the bonding layer 30. Thus, the semiconductor wafer W whose temperature has risen during various processings is cooled, and heat removal (heat extraction) from the semiconductor wafer W is performed. For such a base member 20, a refrigerant flow path 23 for flowing a refrigerant (for example, a fluorine-based inert liquid, water, etc.) is formed. By flowing the refrigerant in this refrigerant flow path 23, the base member 20 is cooled, and the plate-shaped member 10 is cooled through the bonding layer 30. Thus, the semiconductor wafer W whose temperature has risen during various processings is cooled, and heat removal (heat extraction) from the semiconductor wafer W is performed. For such a base member 20, a refrigerant flow path 23 for flowing a refrigerant (for example, a fluorine-based inert liquid, water, etc.) is formed. By flowing the refrigerant in this refrigerant flow path 23, the base member 20 is cooled, and the plate-shaped member 10 is cooled through the bonding layer 30. Thus, the semiconductor wafer W whose temperature has risen during various processings is cooled, and heat removal (heat extraction) from the semiconductor wafer W is performed. For such a base member 20, a refrigerant flow path 23 for flowing a refrigerant (for example, a fluorine-based inert liquid, water, etc.) is formed. By flowing the refrigerant in this refrigerant flow path 23, the base member 20 is cooled, and the plate-shaped member 10 is cooled through the bonding layer 30. Thus, the semiconductor wafer W whose temperature has risen during various processings is cooled, and heat removal (heat extraction) from the semiconductor wafer W is performed. For such a base member 20, a refrigerant flow path 23 for flowing a refrigerant (for example, a fluorine-based inert liquid, water, etc.) is formed. By flowing the refrigerant in this refrigerant flow path 23, the base member 20 is cooled, and the plate-shaped member 10 is cooled through the bonding layer 30. Thus, the semiconductor wafer W whose temperature has risen during various processings is cooled, and heat removal (heat extraction) from the semiconductor wafer W is performed.

[0045] Also, a connection electrode 70 may be formed on the surface of the base member 20. In this embodiment, the connection electrode 70 may be formed on the entire surface of the base member 20 except for the upper surface 21a. This connection electrode 70 can be manufactured, for example, by spraying aluminum (cold spray method) to form a film on the surface of the base member 20. This connection electrode 70 is electrically connected to the first bonding layer 30a described later. Also, a power supply terminal 71 connected to a high-frequency power supply is connected to the connection electrode 70 on the lower surface 22 side of the base member 20. Note that the connection electrode 70 only needs to be in a shape capable of supplying power to the first bonding layer 30a, and it does not need to be formed on the entire base member 20, and it may be formed on only a part of the surface of the base member 20, or it may be formed in a shape excluding a part from the entire surface of the base member 20. Also, a connection electrode 70 may be formed on the surface of the base member 20. In this embodiment, the connection electrode 70 may be formed on the entire surface of the base member 20 except for the upper surface 21a. This connection electrode 70 can be manufactured, for example, by spraying aluminum (cold spray method) to form a film on the surface of the base member 20. This connection electrode 70 is electrically connected to the first bonding layer 30a described later. Also, a power supply terminal 71 connected to a high-frequency power supply is connected to the connection electrode 70 on the lower surface 22 side of the base member 20. Note that the connection electrode 70 only needs to be in a shape capable of supplying power to the first bonding layer 30a, and it does not need to be formed on the entire base member 20, and it may be formed on only a part of the surface of the base member 20, or it may be formed in a shape excluding a part from the entire surface of the base member 20. Also, a connection electrode 70 may be formed on the surface of the base member 20. In this embodiment, the connection electrode 70 may be formed on the entire surface of the base member 20 except for the upper surface 21a. This connection electrode 70 can be manufactured, for example, by spraying aluminum (cold spray method) to form a film on the surface of the base member 20. This connection electrode 70 is electrically connected to the first bonding layer 30a described later. Also, a power supply terminal 71 connected to a high-frequency power supply is connected to the connection electrode 70 on the lower surface 22 side of the base member 20. Note that the connection electrode 70 only needs to be in a shape capable of supplying power to the first bonding layer 30a, and it does not need to be formed on the entire base member 20, and it may be formed on only a part of the surface of the base member 20, or it may be formed in a shape excluding a part from the entire surface of the base member 20. Also, a connection electrode 70 may be formed on the surface of the base member 20. In this embodiment, the connection electrode 70 may be formed on the entire surface of the base member 20 except for the upper surface 21a. This connection electrode 70 can be manufactured, for example, by spraying aluminum (cold spray method) to form a film on the surface of the base member 20. This connection electrode 70 is electrically connected to the first bonding layer 30a described later. Also, a power supply terminal 71 connected to a high-frequency power supply is connected to the connection electrode 70 on the lower surface 22 side of the base member 20. Note that the connection electrode 70 only needs to be in a shape capable of supplying power to the first bonding layer 30a, and it does not need to be formed on the entire base member 20, and it may be formed on only a part of the surface of the base member 20, or it may be formed in a shape excluding a part from the entire surface of the base member 20. Also, a connection electrode 70 may be formed on the surface of the base member 20. In this embodiment, the connection electrode 70 may be formed on the entire surface of the base member 20 except for the upper surface 21a. This connection electrode 70 can be manufactured, for example, by spraying aluminum (cold spray method) to form a film on the surface of the base member 20. This connection electrode 70 is electrically connected to the first bonding layer 30a described later. Also, a power supply terminal 71 connected to a high-frequency power supply is connected to the connection electrode 70 on the lower surface 22 side of the base member 20. Note that the connection electrode 70 only needs to be in a shape capable of supplying power to the first bonding layer 30a, and it does not need to be formed on the entire base member 20, and it may be formed on only a part of the surface of the base member 20, or it may be formed in a shape excluding a part from the entire surface of the base member 20. Also, a connection electrode 70 may be formed on the surface of the base member 20. In this embodiment, the connection electrode 70 may be formed on the entire surface of the base member 20 except for the upper surface 21a. This connection electrode 70 can be manufactured, for example, by spraying aluminum (cold spray method) to form a film on the surface of the base member 20. This connection electrode 70 is electrically connected to the first bonding layer 30a described later. Also, a power supply terminal 71 connected to a high-frequency power supply is connected to the connection electrode 70 on the lower surface 22 side of the base member 20. Note that the connection electrode 70 only needs to be in a shape capable of supplying power to the first bonding layer 30a, and it does not need to be formed on the entire base member 20, and it may be formed on only a part of the surface of the base member 20, or it may be formed in a shape excluding a part from the entire surface of the base member 20. Also, a connection electrode 70 may be formed on the surface of the base member 20. In this embodiment, the connection electrode 70 may be formed on the entire surface of the base member 20 except for the upper surface 21a. This connection electrode 70 can be manufactured, for example, by spraying aluminum (cold spray method) to form a film on the surface of the base member 20. This connection electrode 70 is electrically connected to the first bonding layer 30a described later. Also, a power supply terminal 71 connected to a high-frequency power supply is connected to the connection electrode 70 on the lower surface 22 side of the base member 20. Note that the connection electrode 70 only needs to be in a shape capable of supplying power to the first bonding layer 30a, and it does not need to be formed on the entire base member 20, and it may be formed on only a part of the surface of the base member 20, or it may be formed in a shape excluding a part from the entire surface of the base member 20. Also, a connection electrode 70 may be formed on the surface of the base member 20. In this embodiment, the connection electrode 70 may be formed on the entire surface of the base member 20 except for the upper surface 21a. This connection electrode 70 can be manufactured, for example, by spraying aluminum (cold spray method) to form a film on the surface of the base member 20. This connection electrode 70 is electrically connected to the first bonding layer 30a described later. Also, a power supply terminal 71 connected to a high-frequency power supply is connected to the connection electrode 70 on the lower surface 22 side of the base member 20. Note that the connection electrode 70 only needs to be in a shape capable of supplying power to the first bonding layer 30a, and it does not need to be formed on the entire base member 20, and it may be formed on only a part of the surface of the base member 20, or it may be formed in a shape excluding a part from the entire surface of the base member 20. Also, a connection electrode 70 may be formed on the surface of the base member 20. In this embodiment, the connection electrode 70 may be formed on the entire surface of the base member 20 except for the upper surface 21a. This connection electrode 70 can be manufactured, for example, by spraying aluminum (cold spray method) to form a film on the surface of the base member 20. This connection electrode 70 is electrically connected to the first bonding layer 30a described later. Also, a power supply terminal 71 connected to a high-frequency power supply is connected to the connection electrode 70 on the lower surface 22 side of the base member 20. Note that the connection electrode 70 only needs to be in a shape capable of supplying power to the first bonding layer 30a, and it does not need to be formed on the entire base member 20, and it may be formed on only a part of the surface of the base member 20, or it may be formed in a shape excluding a part from the entire surface of the base member 20.

[0046] And, in order to ensure the insulation of the connection electrode 70, the connection electrode 70 is covered with an insulating film 72 and is. That is, in the present embodiment, since the connection electrode 70 is formed on the entire surface of the base member 20 excluding the upper surface 21a, the entire surface of the base member 20 excluding the upper surface 21a is covered with the insulating film 72 . This insulating film 72 can be formed, for example, by spraying alumina, anodized film, yttria, etc .

[0047] Furthermore, through holes 24, 25, 26 that penetrate in the Z-axis direction between the upper surfaces 21a, 21b and the lower surface 22 are formed in the base member 20 . These through holes 24, 25, 26 are holes for arranging the power supply terminals 63, 66, 69 .

[0048] Note that in the base member 20, there are also formed through holes that form a part of the lift pin holes 17 for arranging lift pins for lifting the semiconductor wafer W held between the upper surfaces 11a, 11b of the plate-like member 10 and the focus ring FR, and for supplying an inert gas (for example, He gas, etc.) to the minute space between the semiconductor wafer W held on the upper surface 11a and the focus ring FR .

[0049] As shown in FIGS. 1 and 2, the bonding layer 30 is disposed between the plate-like member 10 and the base member 20 and bonds the plate-like member 10 and the base member 20 . This bonding layer 30 has a first bonding layer 30a disposed between the first region R1 (inner portion 10a) of the plate-like member 10 and the base member 20, and a second bonding layer 30b disposed between the second region R2 (outer portion 10b) of the plate-like member 10 and the base member 20 .

[0050] As shown in FIG. 2, the first bonding layer 30a is disposed between the lower surface 12a of the inner portion 10a of the plate-like member 10 and​​​​​​ It is disposed between the upper surface 21a of the base member 20 and thermally joins the inner portion 10a and the base member 20. This first joining layer 30a is composed of a metal joining material mainly composed of a metal material. As such a metal joining material, for example, a metal adhesive that joins using metal powder or metal foil, a metal mesh such as metal fibers, porous materials, and mesh structures, and a brazing material Or a material composed of a plurality of columnar metal pieces and a brazing material can be used. As the metal for forming the metal adhesive, metal mesh, or metal pieces, aluminum, Indium, titanium, nickel, copper, brass, alloys thereof, or stainless steel can be used. Note that the main component being a metal material means that the metal component Is most contained in the components of the joining material. The thickness (dimension in the Z-axis direction) of this first joining layer 30a is, for example, about 0.05 mm to 0.5 mm Preferably 0.1 mm to 0.3 mm. The thermal conductivity of the first joining layer 30a is, for example, 100 W / mK to 200 W / mK (preferably 150 W / mK to 180 W / mK) Is desirable within the range. Also, the Young's modulus of the first joining layer 30a is, for example, 0.5 GPa to 10

[0051] 0 GPa (preferably within the range of 20 GPa to 80 GPa) is desirable. The second joining layer 30b is disposed between the lower surface 12b of the outer portion 10b of the plate-like member 10 and the upper surface 21b of the base member 20 as shown in FIG. 2, and thermally joins the outer portion 10b and the base member 20. This second joining layer 30b is composed of a resin adhesive such as a silicone-based resin, an acrylic-based Resin, or an epoxy-based resin.

[0052]

[0053] ​​​​​​The thickness (dimension in the Z-axis direction) of this second bonding layer 30b is, for example, 0.05 mm to 0.5 mm (preferably 0.1 mm to 0.5 mm). Also, the thermal conductivity of the second bonding layer 30b is, for example, 1.0 W / mK. Note that the thermal conductivity of the second bonding layer 30b (assuming a silicone-based resin) is desirably within the range of 0.1 W / mK to 2.0 W / mK (preferably 0.5 W / mK to 1.5 W / mK). Also, the Young's modulus of the second bonding layer 30b is desirably within the range of, for example, 0.5 M Pa to 100 MPa (preferably 1 MPa to 10 MPa).

[0054] Also, in this embodiment, in the bonding layer 30, the first bonding layer 30a and the second bonding layer 30b are formed separately. Note that an insulating film 72 is formed in the space where the first bonding layer 30a and the second bonding layer 30b are separated. And the thermal conductivity of the first bonding layer 30a is greater than that of the second bonding layer 30b. Also, the Young's modulus of the first bonding layer 30a is greater than that of the second bonding layer 30b. Further, the thickness of the first bonding layer 30a is smaller (thinner) than that of the second bonding layer 30b.

[0055] The electrostatic chuck 1 having the above configuration is manufactured by the following procedure. First, the inner part 10a of the plate-like member 10 is bonded to the upper surface 20a of the base member 20 via the first bonding layer 30a. Next , a connection electrode 70 is formed on the surface of the base member 20. And an insulating film 72 is formed on the surface of the base member 20 so as to cover the connection electrode 70. Finally, the outer part 10b of the plate-like member 10 is bonded onto the upper surface 21b of the base member 20 (specifically, the insulating film 72 formed on the upper surface 21b) via the second bonding layer 30b. Note that the first bonding layer 30a and the second bonding layer 30b arranged separately An insulating film 72 is located between the laminated layer 30b. After that, processing and the like are performed on each part and the electrostatic chuck 1 is completed.

[0056] In the electrostatic chuck 1 of this embodiment, the plate-like member 10 has an inner part 10a located in the first region R1 and an outer part 10b located in the second region R2. Further, the bonding layer 30 includes a first bonding layer 30a and a second bonding layer 30b. The inner part 10a of the plate-like member 10 is bonded to the base member 20 via the first bonding layer 30a, and the outer part 10b of the plate-like member 10 is bonded to the base member 20 via the second bonding layer 30b.

[0057] And since the thermal conductivity of the first bonding layer 30a is greater than the thermal conductivity of the second bonding layer 30b , heat transfer between the first region R1 (inner part 10a) of the plate-like member 10 and the base member 20 via the first bonding layer 30a can be promoted. Therefore, heat transfer from the semiconductor wafer W to be held to the plate-like member 10 and the base member 20 is efficiently performed, so that the heated semiconductor wafer W can be efficiently cooled in a short time. That is, the heat dissipation from the semiconductor wafer W to be held can be improved.

[0058] Also, since the Young's modulus of the first bonding layer 30a is greater than the Young's modulus of the second bonding layer 20b, in the second region R2 of the plate-like member 10 where the difference in thermal deformation amount between the base member 20 and the plate-like member 10 tends to be large, the difference in thermal expansion between the plate-like member 10 (outer part 10b) and the base member 20 <00> can be firmly absorbed by the second bonding layer 30b. Therefore, when thermal deformation occurs in the electrostatic chuck 1, in the plate-like member 10 where poor bonding is likely to occur between the base member 20 and the plate-like member 10 ​​​​​In the second region R2 (outer portion 10b), the second bonding layer 30b can prevent the occurrence of a bonding failure between the base member 20 and the plate-shaped member 10.

[0059] Furthermore, since the first bonding layer 30a is formed of a bonding material mainly composed of a metal material, heat transfer between the base member 20 and the plate-shaped member 10 can be further promoted in the first region R1 of the plate-shaped member 10. As a result, the heat dissipation property from the semiconductor wafer W to be held can be further improved.

[0060] Here, when a metal bonding material is used, if the difference in the coefficient of thermal expansion between the plate-shaped member 10 and the base member 20 is large, there is a risk of bonding failure when the electrostatic chuck 1 undergoes thermal deformation. Therefore, in the electrostatic chuck 1, the base member 20 is formed of ceramics or a metal-ceramics composite material.

[0061] Therefore, since the difference in the coefficient of thermal expansion between the plate-shaped member 10 and the base member 20 is small, even if a metal bonding material is used for the first bonding layer 30a, the plate-shaped member 10 and the base member 20 can be firmly bonded together. Therefore, it is possible to prevent the occurrence of a bonding failure between the first region R1 of the plate-shaped member 10 and the base member 20 due to the first bonding layer 30a using a metal bonding material. As a result, heat transfer from the semiconductor wafer W to be held to the plate-shaped member 10 (inner portion 10a) and the base member 20 can be efficiently performed, so that the heat dissipation property from the semiconductor wafer W can be improved.

[0062] Also, since the difference in the coefficient of thermal expansion between the plate-shaped member 10 and the base member 20 is small, even if the thickness of the second bonding layer 30b that bonds the second region R2 of the plate-shaped member 10 and the base member 20 is reduced, bonding failure will not occur. ​​​​​​​​Therefore, the thickness of the second bonding layer 30b using the resin bonding material can be reduced. This allows for a greater reduction in the amount of work required for the focus ring FR and semiconductor wafer W to be held compared to conventional equipment. This promotes heat transfer from the plate-like member 10 to the base member 20. The heat dissipation performance in 1 can be further improved.

[0063] In the bonding layer 30, the first bonding layer 30a and the second bonding layer 30b are formed as separate layers. Therefore, the first bonding layer and the second bonding layer are spaced apart. The positions of the bonding layer 30a and the second bonding layer 30b can be freely adjusted. This allows the thickness of the first region R1 (inner portion 10a) of the plate-like member 10 to be reduced. Therefore, it is possible to further improve the heat dissipation from the semiconductor wafer W that is held. In the member 10, the balance of heat transfer between the first region R1 and the second region R2 is You can also adjust the

[0064] The thickness of the first bonding layer 30a is equal to or less than the thickness of the second bonding layer 30b. The thickness of the material is such that a thin material improves heat dissipation, while a thick material can provide stress relief. The inside of the layer 30 (first bonding layer 30a) can improve the heat dissipation property, and the outside The (second bonding layer 30b) can absorb the difference in thermal expansion. By controlling the thickness of the first bonding layer 30a and the second bonding layer 30b, The first bonding layer 30a located on the inner side improves the heat dissipation property, and the second bonding layer 30b located on the outer side improves the heat dissipation property. In this case, the effect of absorbing the thermal expansion difference can be further enhanced.

[0065] Furthermore, in the electrostatic chuck 1, a connection electrode 70 is formed on the surface of the base member 20, and the connection electrode 70 is electrically connected to the first bonding layer 30a. And, on the lower surface 22 side of the base member 20, a power supply terminal 71 connected to a high-frequency power supply is connected to the connection electrode 70 .

[0066] Thereby, the first bonding layer 30a can be used as a high-frequency electrode. Therefore, the number of internal electrodes provided in the first region R1 of the plate-like member 10 can be reduced. Accordingly, the thickness of the portion of the plate-like member 10 (that is, the inner portion 10a) located in the region (first region R1) where the semiconductor wafer W is placed can be made thinner, so that the heat dissipation property from the semiconductor wafer W can be further improved. Also, since there is no need to provide a through hole for arranging the power supply terminal in the base member 20, the heat uniformity on the upper surface 11a for holding the semiconductor wafer W can be improved.

[0067] As described above, according to the electrostatic chuck 1 of the present embodiment, the bonding layer 30 includes the first bonding layer 30a and the second bonding layer 30b, and the thermal conductivity of the first bonding layer 30a is greater than that of the second bonding layer 30b. Therefore, the heat transfer between the base member 20 and the first region R1 of the plate-like member 10 through the first bonding layer 30a can be promoted. Accordingly, the heat transfer from the semiconductor wafer W to be held to the plate-like member 10 and the base member 20 is efficiently performed, so that the heat dissipation property from the semiconductor wafer W can be improved. Thereby, the temperature of the semiconductor wafer W that has become high can be reduced in a short time.

[0068] Also, since the Young's modulus of the first bonding layer 30a is greater than that of the second bonding layer 30b, In the second region R2 of the plate-like member 10 where the difference in thermal deformation from the base member 20 is likely to be large , the difference in thermal expansion between the plate-like member 10 (outer portion 10b) and the base member 20 is absorbed firmly by the second bonding layer 30b. Therefore, when thermal deformation occurs in the electrostatic chuck 1 , in the second region R2 of the plate-like member 10 where poor bonding is likely to occur between the plate-like member 10 and the base member 20 , the second bonding layer 30b can prevent the occurrence of poor bonding between the base member 20 and the plate-like member 10 (outer portion 10b).

[0069] <Modification Example> Subsequently, a modification example of the above embodiment will be described with reference to FIG. 3. This modification example has the same basic configuration as the above embodiment, but is different in that it is composed of a plurality of members with different base member materials . Therefore, the same reference numerals are given to the same configurations as in the above embodiment and the description thereof is omitted, and the description will be centered on the differences

[0070] In the electrostatic chuck 1a according to the modification example, as shown in FIG. 3, the base member 120 includes a first base member 121 and a second base member 122. And the first base member 121 and the second base member 122 are joined and integrated by a base bonding layer 123. That is , the base member 120 is formed by laminating a plurality of members

[0071] The first base member 121 is a member of the same material as the base member 20 in the above embodiment( for example, ceramics (such as SiC, etc.) or a metal-ceramics composite material (Ti / SiC composite material, MMC (Al / SiC composite material), etc.). On the other hand, the second base member 122 is a member of the same material as the plate-like member 10 in the above embodiment (for example, oxide ​It is formed of ceramics having aluminum (alumina, Al2O3) or aluminum nitride (AlN) as a main component and the like).

[0072] And a plate-like member 10 (a first plate-like member 10a, a second plate-like member 10b) is joined to the upper surface side of the first base member 121. That is, similar to the above-described embodiment, with respect to the plate-like member 10, a first base member 121 having a small difference in coefficient of thermal expansion from the plate-like member 10 and a high thermal conductivity is joined. Therefore, the heat extraction property of the plate-like member 10 can be improved, and the occurrence of poor bonding between the plate-like member 1 0 and the base member 20 can be prevented.

[0073] On the other hand, a second base member 122 formed of a material different from that of the first base member 121 and having excellent corrosion resistance is joined to the lower surface side of the first base member 121. Although the MMC single body itself has sufficient corrosion resistance, by forming the second base member 122 with ceramics having more excellent corrosion resistance, the generation of foreign matter from the through holes (for example, gas holes 15, lift pin holes 17, etc.) of the base member 120 can be prevented. Therefore, contamination in the chamber of the semiconductor manufacturing apparatus using the electrostatic chuck 1a can be prevented.

[0074] Also, in the base member 120, a member made of a material having good workability and low cost (for example, alumina, etc.) is used for the second base member arranged on the side opposite to the upper surface side in contact with the plate-like member 10. By doing so, the productivity (workability) of the electrostatic chuck 1a can be improved and the manufacturing cost can be reduced.

[0075] According to the electrostatic chuck 1a according to this modification, the base member 120 is composed of a plurality of members ( The first base member 121 and the second base member 122 are laminated to form the first base member 1 21 uses a member having a small difference in coefficient of thermal expansion from the plate-like member 10 and a large thermal conductivity, and the second base member 122 uses a member made of a material having excellent corrosion resistance, good workability, and low cost. Thus, in addition to improving the heat extraction performance of the plate-like member 10, it is possible to prevent the generation of foreign matter from the through holes (for example, the gas hole 15, the lift pin hole 17, etc.) of the base member 120. Moreover, it is possible to improve the productivity (workability) of the electrostatic chuck 1a and reduce the manufacturing cost at the same time.

[0076] Note that the above embodiments are merely illustrative and do not limit the present disclosure in any way, and of course, various improvements and modifications are possible without departing from the gist thereof. For example, in the above embodiment, as the plate-like member 10, the case where the inner portion 10a and the outer portion 10b have a separate structure and are separated from each other is illustrated, but the present disclosure can also be applied even when the inner portion 10a and the outer portion 10b are integrated . Moreover, in the above embodiment, the case where the first bonding layer 30a is formed of a metal bonding material is illustrated, but

[0077] the first bonding layer 30a is not limited to a metal bonding material as long as it has a higher thermal conductivity and a higher Young's modulus than the second bonding layer 30b. For example, the first bonding layer 30a can also be formed of a resin bonding material having a higher thermal conductivity and a higher Young's modulus than the second bonding layer. When the first bonding layer 30a is composed of a resin adhesive, for example, silicone-based resins, acrylic-based resins, epoxy-based resins etc. can be used. Also, by changing the amount of the filler added, the thermal conductivity and the Young's modulus of the first bonding layer 30a can be made larger than those of the second bonding layer 30b. When the first bonding layer 30a is composed of a resin adhesive, for example, silicone-based resins, acrylic-based resins, epoxy-based resins etc. can be used. Also, by changing the amount of the filler added, the thermal conductivity and the Young's modulus of the first bonding layer 30a can be made larger than those of the second bonding layer 30b.

[0078] Also, in the above-described embodiment, the case where the second bonding layer 30b is formed of a resin bonding material has been exemplified. However, the second bonding layer 30b is not limited to a resin bonding material as long as its thermal conductivity is lower and its Young's modulus is lower than those of the first bonding layer. For example, the second bonding layer 30b can also be formed of a metal bonding material having a lower thermal conductivity and a lower Young's modulus than the first bonding layer 30a. When the second bonding layer 30b is formed of a metal bonding material, for example, aluminum, indium, titanium, nickel, copper, brass, alloys thereof, or stainless steel can be used. Furthermore, in the above-described embodiment, the case where the connection electrode 70 is formed on the surface of the base member 20 has been exemplified. However, when the base member 20 has conductivity (for example, when the base member is formed of metal or MMC), the connection electrode 70 does not have to be formed. This is because when the base member 20 has conductivity, the base member 20 and the first bonding layer 30a can be electrically connected.

[0079]

Description of Reference Numerals

[0080] 1 Electrostatic chuck 10 Plate-like member 10a Inner portion 10b Outer portion 20 Base member 30 Bonding layer 30a First bonding layer 30b Second bonding layer 70 Connection electrode 120 Base member 121 First base member 122 Second base member 123 Base bonding layer FR Focus ring R1 First region R2 Second region W Semiconductor wafer​​​​​

Claims

1. A holding device comprising a plate-like member, a base member, and a bonding layer that bonds the plate-like member and the base member. In the holding device, the plate-like member has a first region at the central portion in the plane direction and a second region at the outer peripheral portion in the plane direction. The bonding layer has a first bonding layer disposed between the first region and the base member and a second bonding layer disposed between the second region and the base member. The thermal conductivity of the first bonding layer is greater than that of the second bonding layer, and the Young's modulus of the first bonding layer is greater than that of the second bonding layer. The holding device is characterized by the above.

2. The holding device according to Claim 1, wherein the first bonding layer is formed separately from the second bonding layer. The holding device is characterized by the above.

3. The holding device according to Claim 1, wherein the first bonding layer is formed of a bonding material mainly composed of a metal material. The holding device is characterized by the above.

4. The holding device according to Claim 1, wherein the plate-like member is formed of ceramics, and the base member is formed of ceramics or a metal-ceramics composite material. The holding device is characterized by the above.

5. The holding device according to Claim 1, wherein the thickness of the first bonding layer is less than or equal to the thickness of the second bonding layer. The holding device is characterized by the above.

6. The holding device according to Claim 3, wherein a connection electrode is formed on the surface of the base member, and the connection electrode is electrically connected to the first bonding layer. The holding device is characterized by the above.

7. The holding device according to Claim 1, wherein the base member is formed by laminating a plurality of members, and the materials of the plurality of members are different. The holding device is characterized by the above.

8. A holding device comprising a plate-like member, a base member, and a bonding layer that bonds the plate-like member and the base member. In the holding device, the plate-like member has a first region at the central portion in the plane direction and a second region at the outer peripheral portion in the plane direction. The bonding layer has a first bonding layer disposed between the first region and the base member and a second bonding layer disposed between the second region and the base member. The first bonding layer is formed separately from the second bonding layer, and the first bonding layer is formed of a bonding material mainly composed of a metal material. The holding device is characterized by the above. The holding device is characterized by the above. ​

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