Retention device

Abstract

To provide a retainer applicable to semiconductor manufacturing at low temperatures.SOLUTION: A retainer has a plate member 10 having a first surface 10A for holding an object and a second surface 10B located on the opposite side of the first surface 10A, an electrode member formed inside the plate member 10 or on the second surface 10B, a plurality of terminals 14A electrically connected to the electrode member, and an adhesive member 15 disposed between the plurality of terminals 14A, and the adhesive member 15 is silicone resin SR having hardness of 2 to 10 on the Shore A hardness scale.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] As an example of a holding device, a sample holder described in Patent Document 1 below is known. This sample holder includes a substrate having a sample holding surface on the upper surface, a heating resistor provided inside or on the lower surface of the substrate, and a metal member attached via a first adhesive layer. The metal member and the first adhesive layer have a through hole penetrating in the stacking direction. Inside the through hole, a lead terminal connected to the heating resistor is inserted. The lead terminal is fixed to the lower surface of the substrate by a second adhesive layer. As the second adhesive layer, for example, an epoxy adhesive can be used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, some of the semiconductor manufacturing processes may be performed at a low temperature of about -60°C. When the above sample holder is used at such a low temperature, since the thermal expansion coefficients of the ceramics constituting the substrate and the epoxy adhesive, which is an example of the second adhesive layer, are significantly different, cracks may occur in the second adhesive layer due to the cooling cycle. Further, in the case of a form in which the heating resistor and a plurality of lead terminals are joined by soldering or the like and the space between the lead terminals is filled with an epoxy resin to ensure insulation between the lead terminals, since the thermal expansion coefficients of the ceramics constituting the substrate and the epoxy resin are significantly different, cracks may occur in the epoxy resin due to the cooling cycle. In that case, sufficient insulation between the terminals may not be ensured.

[0005] The present disclosure has been completed based on the above circumstances, and an object thereof is to provide a holding device applicable to semiconductor manufacturing at low temperatures. [Means for Solving the Problems]

[0006] The holding device of the present disclosure includes a plate-like member having a first surface for holding an object and a second surface located on the opposite side of the first surface, an electrode member formed inside the plate-like member or on the second surface, a plurality of terminal portions electrically connected to the electrode member, and an adhesive member disposed between the plurality of terminal portions. The adhesive member is a silicone resin having a Shore A hardness of 2 or more and 10 or less. [Effects of the Invention]

[0007] According to the present disclosure, a holding device applicable to semiconductor manufacturing at low temperatures can be provided. [Brief Description of the Drawings]

[0008]

Figure 1

Figure 2

Figure 3

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. (1) The holding device of the present disclosure includes a plate-shaped member having a first surface for holding an object and a second surface located on the opposite side of the first surface, an electrode member formed inside the plate-shaped member or on the second surface, a plurality of terminal portions electrically connected to the electrode member, and an adhesive member disposed between the plurality of terminal portions. The adhesive member is a silicone resin having a Shore A hardness of 2 or more and 10 or less.

[0010] Since the adhesive member is a silicone resin having a Shore A hardness of 2 or more and 10 or less, appropriate flexibility can be obtained. Therefore, the adhesive member can deform following the thermal expansion or contraction of the plate-shaped member. Thus, it is possible to suppress cracks from occurring in the adhesive member. Therefore, it is easy to maintain the insulation between the terminal portions even at low temperatures.

[0011] (2) The glass transition temperature of the silicone resin is preferably -140°C or higher and -100°C or lower.

[0012] According to the above configuration, the holding device can be used at low temperatures on the high-temperature side of the glass transition temperature.

[0013] (3) The silicone resin contains a filler, and the content of the filler is preferably 10% by weight or less.

[0014] Since the content of the filler is 10% by weight or less, it is possible to suppress the silicone resin from becoming excessively hard.

[0015] [Details of Embodiments of the Present Disclosure] A specific example of the holding device of the present disclosure will be described with reference to the following drawings. It should be noted that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all meanings equivalent to the claims and all modifications within the scope. In the following description, for a plurality of identical members, only some members may be labeled, and the labels of other members may be omitted.

[0016] <Electrostatic Chuck> The holding device of the present disclosure is an electrostatic chuck 100 that can adsorb and hold an object such as a semiconductor wafer or a glass substrate (hereinafter referred to as "wafer W"). The electrostatic chuck 100 is attached to a processing chamber of a semiconductor manufacturing apparatus (not shown), for example, and is used to perform various processes (film formation, etching, etc.) on the wafer W using plasma.

[0017] As shown in FIG. 1, the electrostatic chuck 100 includes a plate-like member 10 and a metal member 20. The plate-like member 10 and the metal member 20 are joined by a joining portion 30. The joining portion 30 is composed of an adhesive such as a silicone-based resin, an acrylic-based resin, or an epoxy-based resin, for example. The electrostatic chuck 100 is configured to be able to adsorb and hold the wafer W by electrostatic attraction.

[0018] <Metal Member> The metal member 20 is a disk-shaped member and can be formed into a shape having a diameter of about 340 mm and a thickness of about 35 mm, for example. As shown in FIG. 2, the metal member 20 has a third surface 20A disposed on the side of the plate-like member 10 and a fourth surface 20B disposed on the side opposite to the third surface 20A. The third surface 20A is disposed on the upper side of the metal member 20, and the fourth surface 20B is disposed on the lower side of the metal member 20. The metal member 20 is mainly composed of aluminum, an aluminum alloy, or the like. The third surface 20A of the metal member 20 is joined to the second surface 10B of the plate-like member 10 described later by the joining portion 30.

[0019] A refrigerant flow path 21 is provided inside the metal member 20. The refrigerant flow path 21 is connected to a refrigerant circulation device (not shown). The refrigerant circulation device is configured to be able to circulate a refrigerant such as a fluorine-based inert liquid or water through the refrigerant flow path 21. When the refrigerant is flowed through the refrigerant flow path 21, the metal member 20 is cooled, and the plate-like member 10 is cooled by heat transfer (heat extraction) between the metal member 20 and the plate-like member 10 through the joining portion 30, and the wafer W held on the first surface 10A of the plate-like member 10 described later is cooled. Thereby, the temperature of the wafer W can be controlled.

[0020] The metal member 20 is provided with a terminal hole 22 for receiving a terminal 14 and a connector 17 connected to the terminal 14, which will be described later. The terminal hole 22 is formed to penetrate the metal member 20 in the vertical direction.

[0021] <Plate-like member> The plate-like member 10 has a disk shape as a whole and can be formed into a shape having a diameter of about 300 mm and a thickness of about 5 mm, for example. The plate-like member 10 has a first surface 10A (see FIG. 1) for holding the wafer W and a second surface 10B (see FIG. 2) disposed on the side opposite to the first surface 10A. As shown in FIG. 2, the first surface 10A is disposed on the upper side of the plate-like member 10, and the second surface 10B is disposed on the lower side of the plate-like member 10. The plate-like member 10 includes an insulator 11 made of ceramics, a chuck electrode 12 provided inside the insulator 11, a heater electrode 13 (an example of an electrode member) provided inside the insulator 11 or on the second surface 10B, a terminal 14 electrically connected to the heater electrode 13, and an adhesive member 15 covering the connection portion between the heater electrode 13 and the terminal 14.

[0022] <Insulator> The insulator 11 is mainly composed of alumina, aluminum nitride, yttria, or a composite material of alumina and silicon carbide. A recess 16 recessed from the second surface 10B is formed in the insulator 11. As shown in FIG. 3, the recess 16 includes a bottom surface 16A and a peripheral wall surface 16B connecting the bottom surface 16A and the second surface 10B. A plurality of terminals 14 are arranged in the recess 16.

[0023] The chuck electrode 12 and the heater electrode 13 are mainly composed of tungsten, molybdenum, or alloys thereof, or carbides thereof. As the chuck electrode 12 and the heater electrode 13, a metallized layer obtained by sintering a conductor layer printed with a conductor paste, a metal foil, a metal mesh, or the like may be used. As shown in FIG. 2, the chuck electrode 12 is disposed on the first surface 10A side inside the insulator 11, and the heater electrode 13 is disposed on the second surface 10B side with respect to the chuck electrode 12.

[0024] The chuck electrode 12 is electrically connected to a well-known power supply terminal (not shown). When a DC high voltage is applied to the chuck electrode 12 from a power source (not shown) via the power supply terminal, an electrostatic attraction force is generated. Due to this electrostatic attraction force, the wafer W is adsorbed and fixed to the first surface 10A of the plate-like member 10.

[0025] <Heater electrode> The heater electrode 13 is disposed on the first surface 10A side inside the insulator 11. The heater electrode 13 is electrically connected to a power source (not shown). When an electric current flows through the heater electrode 13, the plate-like member 10 is heated. The plurality of heater electrodes 13 are arranged on a virtual plane substantially parallel to the first surface 10A within the insulator 11. When the plate-like member 10 is viewed from the direction (vertical direction) orthogonal to the first surface 10A, the heater electrodes 13 are arranged so as to form a plurality of concentric heating regions. The heater electrode 13 is electrically connected to a terminal connection portion 13B disposed at an end portion on the second surface 10B side of the insulator 11 via an intermediate conductor 13A. The intermediate conductor 13A includes a via conductor extending in the vertical direction and a driver layer that spreads in the horizontal direction and connects the via conductors to each other.

[0026] <Terminal portion> As shown in FIG. 3, a plurality of terminal connection portions 13B are formed on the bottom surface 16A of the recess 16. The terminal connection portion 13B is electrically connected to the terminal 14. In the present embodiment, the connection between the terminal 14 and the terminal connection portion 13B is made by soldering. The terminal 14 and the terminal connection portion 13B constitute a terminal portion 14A. The tip portion (the upper end portion shown in FIG. 3) of the terminal 14 protrudes outside the recess 16. As shown in FIG. 2, in the electrostatic chuck 100, the tip portion of the terminal 14 enters the terminal hole 22 of the metal member 20. The terminal 14 is connected to a power source (not shown) via a connector 17, a wiring 18, and the like.

[0027] <Adhesive member> As shown in FIG. 3, the connection portion between the terminal 14 and the terminal connection portion 13B is covered by the adhesive member 15. The adhesive member 15 is disposed on the bottom surface 16A side within the recess 16 and separates the respective terminals 14. The adhesive member 15 can protect the connection portion between the terminal 14 and the terminal connection portion 13B. In particular, when the electrostatic chuck 100 undergoes a large temperature change, it is possible to suppress damage to the connection portion between the terminal 14 and the terminal connection portion 13B due to the difference in the linear expansion coefficients of the terminal 14 and the insulator 11. Further, the terminal 14 can be fixed within the recess 16 to prevent contact between the terminals 14. The adhesive member 15 is composed of a curable silicone resin SR. After connecting the terminal 14 to the terminal connection portion 13B, the uncured silicone resin SR is applied within the recess 16 and cured to form the adhesive member 15.

[0028] Conventionally, an epoxy resin has sometimes been used as such an adhesive member. However, unlike the present embodiment, when an epoxy resin is used as the adhesive member, if the electrostatic chuck is cooled to a lower temperature (for example, -60°C) than before, the epoxy resin itself may crack or the connection portion (soldered portion) between the terminal and the terminal connection portion may be damaged. This is due to the epoxy resin being hard (for example, having a Shore D hardness of about 80) and the epoxy resin, the terminal, and the insulator having significantly different linear expansion coefficients.

[0029] On the one hand, the hardness of the silicone resin SR used in the adhesive member 15 of the present embodiment after curing is set to be 2 or more and 10 or less in Shore A hardness. Note that the hardness of the silicone resin SR after curing is measured using a known rubber hardness measuring machine (Type A durometer specified in JIS K 6253). That is, compared with the epoxy resin, the adhesive member 15 of the present embodiment is flexible. Therefore, in a semiconductor manufacturing apparatus equipped with the electrostatic chuck 100, even when a cooling cycle is performed to a lower temperature than before, the adhesive member 15 is flexible, so it can be deformed to follow the thermal expansion or contraction of the insulator 11 and the terminal 14. Therefore, in the electrostatic chuck 100, the terminal 14 can be held at the normal position in the recess 16, and the electrical connection between the terminal 14 and the terminal connection portion 13B can be maintained.

[0030] The glass transition temperature of the silicone resin SR used in the adhesive member 15 is preferably -140°C or higher and -100°C or lower. It is known that below the glass transition temperature, numerical values such as the hardness, linear expansion coefficient, and Young's modulus of the silicone resin SR change. Therefore, it is preferable to perform the cooling cycle of the semiconductor manufacturing apparatus on the higher temperature side than the glass transition temperature where the hardness (flexibility) and the like are stable. In the present disclosure, since the use of the semiconductor manufacturing apparatus and the electrostatic chuck 100 at particularly low temperatures (for example, -60°C or -80°C) is an issue, the above-described glass transition temperature is suitable.

[0031] To control the glass transition temperature of the silicone resin SR to -100°C or lower, for example, as disclosed in Japanese Patent Application Laid-Open No. 2020-23088, a method of introducing a predetermined amount of a phenyl group into the polyorganosiloxane constituting the silicone resin SR is known.

[0032] The silicone resin SR used for the connecting member 15 may contain fillers such as alumina and aluminum nitride. By adding fillers, the viscosity of the silicone resin SR, the hardness, thermal conductivity, color, etc. of the adhesive member 15 can be adjusted. However, when the filler content increases, the viscosity and hardness increase, so the filler content in the silicone resin SR is preferably 10% by weight or less.

[0033] As an example of the silicone resin SR of the present disclosure, a silicone adhesive using the polyorganosiloxane A3 disclosed in FIG. 3 of JP-A-2020-23088 can be mentioned. However, note that in the silicone adhesive described in JP-A-2020-23088, since the addition amount of alumina particles as a filler is large, the hardness is high. For example, in the silicone adhesive as the sample S3 in FIG. 3 of JP-A-2020-23088, when alumina particles are not added, the hardness of the silicone adhesive can be within the hardness range of the present disclosure (2 or more and 10 or less in Shore A hardness).

[0034] Regarding the filling amount of the silicone resin SR into the recess 16, it may be appropriately determined from the stress applied to the terminal 14 and the terminal connection portion 13B along with the cooling cycle. The filling amount of the silicone resin SR can be determined based on the volume of the recess 16, the height of the peripheral wall surface 16B, etc. For example, the filling amount of the silicone resin SR may be 40% or less with respect to the volume of the recess 16. Also, the thickness (dimension in the vertical direction) of the adhesive member 15 may be 30% or less of the height of the peripheral wall surface 16B. Here, the thickness of the adhesive member 15 is defined by the thickness of the flat portion away from the peripheral wall surface 16, not the thickness of the thick portion (fillet) formed near the peripheral wall surface 16B due to surface tension. By adjusting the filling amount of the silicone resin SR in this way, it is possible to suppress the stress applied to the terminal 14 and the insulator 11 from becoming excessive due to the volume change of the adhesive member 15 accompanying temperature changes. Therefore, it is easy to maintain the electrical connection between the terminal 14 and the terminal connection portion 13B.

[0035] <Effects of the Embodiment> As described above, the holding device (electrostatic chuck 100) of the present embodiment includes a plate-shaped member 10 having a first surface 10A for holding an object (wafer W) and a second surface 10B located on the opposite side of the first surface 10A, an electrode member (heater electrode 13) formed inside the plate-shaped member 10 or on the second surface 10B, a plurality of terminal portions 14A electrically connected to the electrode member, and an adhesive member 15 disposed between the plurality of terminal portions 14A. The adhesive member 15 is a silicone resin SR having a Shore A hardness of 2 or more and 10 or less.

[0036] Since the adhesive member 15 is a silicone resin SR having a Shore A hardness of 2 or more and 10 or less, an appropriate flexibility can be obtained. For this reason, the adhesive member 15 can deform following the thermal expansion or contraction of the plate-shaped member 10. Therefore, it is possible to suppress the occurrence of cracks in the adhesive member 15. Accordingly, it is easy to maintain the insulation between the terminal portions 14A even at low temperatures.

[0037] In the holding device of the present embodiment, the glass transition temperature of the silicone resin SR is preferably -140°C or higher and -100°C or lower.

[0038] According to the above configuration, the holding device can be used at low temperatures on the high-temperature side of the glass transition temperature.

[0039] In the holding device of the present embodiment, the silicone resin SR contains a filler, and the content of the filler is preferably 10% by weight or less.

[0040] Since the content of the filler is 10% by weight or less, it is possible to suppress the silicone resin SR from becoming excessively hard.

[0041] <Other Embodiments> (1) In the embodiment, the terminal 14 and the terminal connection portion 13B are electrically connected by brazing, but the terminal and the terminal connection portion may be electrically connected by other methods.

[0042] (2) In the embodiment, the heater electrode 13, which is an example of the electrode member, is provided inside the insulator 11, and the terminal connection portion 13 was arranged on the bottom surface 16A of the recess 16, but the terminal connection portion may be arranged on the second surface.

Description of Reference Numerals

[0043] 10... plate-like member 10A... first surface 10B... second surface 11... insulator 12... chuck electrode 13... heater electrode (electrode member) 13A... intermediate conductor 13B... terminal connection portion 14... terminal 14A... terminal portion 15... adhesive member 16... recess 16A... bottom surface 16B... peripheral wall surface 17... connector 18... wiring 20... metal member 20A... third surface 20B... fourth surface 21... refrigerant flow path 22... terminal hole 30... joint portion 100... electrostatic chuck (holding device) SR... silicone resin W... wafer (object)

Claims

1. A plate-like member having a first surface for holding an object and a second surface located on the opposite side of the first surface; An electrode member formed inside the plate-like member or on the second surface; A plurality of terminal portions electrically connected to the electrode member; An adhesive member disposed between the plurality of terminal portions, and The holding device, wherein the adhesive member is a silicone resin having a Shore A hardness of 2 or more and 10 or less.

2. The holding device according to claim 1, wherein the glass transition temperature of the silicone resin is -140°C or more and -100°C or less.

3. The silicone resin contains a filler, and The holding device according to claim 1 or claim 2, wherein the content of the filler is 10% by weight or less.

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