substrate fixing device

Abstract

To provide a substrate fixing device that can reduce discharge. [Solution] The substrate fixing device 1 includes a metal part 10 having a first through hole 18 that reaches a first surface 10A and a second surface 10B, and a recess 60 formed on the first surface surrounding the first through hole; a cylindrical first insulating member 20 containing zirconia, provided in the recess, and having a second through hole 28 that communicates with the first through hole; an electrostatic chuck 30 facing the first surface, having a base 31 and an electrode 32 built into the base; an adhesive layer 40 that bonds the metal part and the first insulating member to the electrostatic chuck; and a terminal 33 electrically connected to the electrode. The recess has a first recess that communicates with the first through hole and a second recess that is shallower than the first recess and extends away from the first through hole. The first insulating member has a base provided in the first recess and having a second through hole, and a flange provided in the second recess and extending away from the base.

Description

[Technical Field]

[0001] The present disclosure relates to a substrate fixing apparatus. [Background Art]

[0002] Conventionally, film forming apparatuses and plasma etching apparatuses used in manufacturing semiconductor devices include a stage for accurately holding a substrate such as a silicon wafer in a vacuum processing chamber. As such a stage, for example, a substrate fixing apparatus that sucks and holds a substrate by an electrostatic chuck mounted on a base plate has been proposed.

[0003] The substrate fixing apparatus includes a base plate, a heater provided on the base plate, and an electrostatic chuck provided on the heater. The electrostatic chuck incorporates an electrode for sucking the substrate. A through hole is formed in the base plate and the heater, and a terminal connected to the electrode is provided in the through hole. By supplying power to the electrode through the terminal, the substrate is sucked onto the substrate fixing apparatus. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 2019-220503 [Patent Document 2] Japanese Unexamined Patent Publication No. 2024-131204 [Patent Document 3] Japanese Unexamined Patent Publication No. 2021-132177 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] In conventional substrate fixing apparatuses, discharge may occur between metal parts including the base plate and the heater and the tip end of the terminal during use. When discharge occurs, the suction force for the substrate may be reduced.

[0006] The purpose of this disclosure is to provide a substrate fixing device that can reduce discharge. [Means for solving the problem]

[0007] According to one embodiment of the present disclosure, a metal part having a first surface and a second surface opposite to the first surface, having a first through-hole that reaches the first surface and the second surface, and having a recess on the first surface that surrounds the first through-hole in a plan view; a cylindrical first insulating member containing zirconia, provided in the recess, and having a second through-hole that communicates with the first through-hole; an electrostatic chuck having a third surface facing the first surface, a base body, and an electrode embedded in the base body; and the metal part, the first insulating member, and the electrostatic chuck. A substrate fixing device is provided, comprising: an adhesive layer for bonding; terminals provided in the first through-hole and the second through-hole and electrically connected to the electrode, wherein the recess comprises a first recess communicating with the first through-hole and a second recess shallower than the first recess and extending away from the first through-hole, and the first insulating member comprises a base provided in the first recess and having the second through-hole formed thereon, and a flange provided in the second recess and extending away from the base in a direction away from the second through-hole. [Effects of the Invention]

[0008] According to this disclosure, discharge can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view illustrating a substrate fixing device according to an embodiment. [Figure 2] This is a cross-sectional view illustrating a bush and metal parts included in a substrate fixing device according to an embodiment. [Figure 3] This is a plan view illustrating metal parts, bushings, sleeves, and power supply pins included in the substrate fixing device according to the embodiment. [Figure 4] This is a flowchart illustrating a method for manufacturing a substrate fixing device according to an embodiment. [Figure 5]This is a cross-sectional view (part 1) illustrating a method for manufacturing a substrate fixing device according to an embodiment. [Figure 6] This is a cross-sectional view (part 2) illustrating a method for manufacturing a substrate fixing device according to an embodiment. [Figure 7] This is a cross-sectional view (part 3) illustrating a method for manufacturing a substrate fixing device according to an embodiment. [Figure 8] This is a cross-sectional view illustrating a substrate fixing device according to a comparative example. [Figure 9] This diagram illustrates an example of a tensile shear test. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configuration will be denoted by the same reference numerals to avoid redundant descriptions.

[0011] [Structure of the substrate fixing device] This embodiment relates to a substrate fixing device. First, the structure of the substrate height adjustment device according to the embodiment will be described. Figure 1 is a cross-sectional view illustrating the substrate fixing device according to the embodiment. Figure 2 is a cross-sectional view illustrating the bush and metal parts included in the substrate fixing device according to the embodiment. Figure 3 is a plan view illustrating the metal parts, bush, sleeve and power supply pin included in the substrate fixing device according to the embodiment. Figure 1 corresponds to a cross-sectional view along line II in Figure 3. Figure 3(a) illustrates the bush, and Figure 3(b) illustrates the metal parts.

[0012] As shown in Figures 1 to 3, the substrate fixing device 1 according to this embodiment includes a metal part 10, a bush 20, a sleeve 70, an electrostatic chuck 30, an adhesive layer 40, and a power supply pin 50.

[0013] In this embodiment, for convenience, the side on which the electrostatic chuck 30 is located when viewed from the metal part 10 is referred to as the upper side or one side, and the side on which the metal part 10 is located when viewed from the electrostatic chuck 30 is referred to as the lower side or the other side.

[0014] The metal component 10 includes a base plate 11, a heater 12, and an adhesive layer 13. The heater 12 is bonded onto the base plate 11 via the adhesive layer 13. The metal component 10 has an upper surface 10A and a lower surface 10B opposite to the upper surface 10A. The heater 12 has the upper surface 10A, and the base plate 11 has the lower surface 10B. The base plate 11 and the heater 12 are mainly composed of aluminum or aluminum alloy. For example, the base plate 11 and the heater 12 are made of aluminum or aluminum alloy. In the present disclosure, the main component refers to a component with the highest content ratio. For the material of the adhesive layer 13, for example, a silicone resin-based adhesive is used. The upper surface 10A is an example of a first surface, and the lower surface 10B is an example of a second surface.

[0015] The metal component 10 is formed in a circular plate shape, for example. The planar shape of the metal component 10 is, for example, circular. The diameter of the metal component 10 is, for example, approximately 200 mm to 300 mm. The thickness of the base plate 11 is, for example, approximately 20 mm to 50 mm.

[0016] A first through hole 18 is formed in the metal component 10. The first through hole 18 extends to the upper surface 10A and the lower surface 10B, and penetrates the metal component 10 in the vertical direction. The diameter of the first through hole 18 is, for example, 5 mm to 6 mm. A recess 60 is formed in the upper surface 10A. The recess 60 surrounds the first through hole 18 in a plan view, and is recessed toward the lower surface 10B. For example, the planar shapes of the first through hole 18 and the recess 60 are circular, and the first through hole 18 and the recess 60 are formed concentrically with each other. In the present disclosure, plan view refers to viewing an object from a direction perpendicular to the upper surface 10A, and planar shape refers to the shape of the object in plan view.

[0017] The recess 60 includes a first recess 61 and a second recess 62. The first recess 61 communicates with the first through hole 18. The second recess 62 extends from the first recess 61 in a direction away from the first through hole 18, that is, in the radial direction. The second recess 62 is shallower than the first recess 61. For example, the bottom of the first recess 61 is located on the base plate 11, and the bottom of the second recess 62 is located on the heater 12. For example, the first recess 61 and the second recess 62 are formed concentrically with the first through hole 18. On the upper surface 10A, the edge of the recess 60 is spaced from the center of the first through hole 18 by, for example, 3 mm or more and 10 mm or less.

[0018] The bush 20 is disposed in the recess 60. The bush 20 contains zirconia. The bush 20 includes zirconia as a main component. The bush 20 contains zirconia with a purity of 94% by mass or more, for example. The bush 20 preferably contains zirconia with a purity of 97% by mass or more, and more preferably contains zirconia with a purity of 99% by mass or more. For example, the bush 20 is manufactured through firing without using a sintering aid. A second through hole 28 communicating with the first through hole 18 is formed in the bush 20. The second through hole 28 penetrates the bush 20 in the axial direction. The bush 20 has an upper surface 20A. The upper surface 20A may be flush with the upper surface 10A of the metal component 10.

[0019] The bush 20 includes a base portion 21 and a flange portion 22. The base portion 21 is disposed in the first recess 61, and the second through hole 28 is formed in the base portion 21. The base portion 21 is fitted into the first recess 61. For example, the base portion 21 has a cylindrical shape. The flange portion 22 is disposed in the second recess 62, and extends from the base portion 21 in a direction away from the second through hole 28, that is, in the radial direction. The flange portion 22 has an upper surface 22A and a lower surface 22B opposite to the upper surface 22A. The lower surface 22B is in contact with the heater 12. The flange portion 22 is fitted into the second recess 62. The upper surface 22A is a part of the upper surface 20A. The upper surface 22A may be flush with the upper surface 10A of the metal component 10. The bush 20 is an example of the first insulating member. The upper surface 22A is an example of the fourth surface, and the lower surface 22B is an example of the fifth surface.

[0020] The electrostatic chuck 30 comprises a base 31, an electrode 32, an electrode pad 33, and a via conductor 34. The electrode 32, electrode pad 33, and via conductor 34 are integrated into the base 31.

[0021] The electrostatic chuck 30 has an upper surface 30A and a lower surface 30B opposite to the upper surface 30A. The lower surface 30B faces the upper surface 10A of the metal part 10. A recess 36 is formed on the lower surface 30B in the portion that overlaps with the first through hole 18 in a plan view, and it is recessed toward the upper surface 10A. The electrode pad 33 is exposed at the bottom of the recess 36. The electrode 32 is positioned on the upper surface 30A side of the electrode pad 33, and a via conductor 34 electrically connects the electrode pad 33 and the electrode 32. The lower surface 30B is an example of a third surface.

[0022] When a predetermined voltage is applied to the electrode 32 from a suction power supply (not shown) located outside the substrate fixing device 1, the electrode 32 generates an electrostatic attraction force between itself and the substrate W placed on the upper surface 30A, which is the substrate mounting surface. This allows the substrate W to be attracted and held on the upper surface 30A. The attraction force in the electrostatic chuck 30 increases with increasing voltage applied to the electrode 32. The electrode 32 may be unipolar or bipolar. Examples of materials for the electrode 32, electrode pad 33, and via conductor 34 include tungsten (W) and molybdenum (Mo). The electrostatic chuck 30 is, for example, a Johnsen-Rabec type electrostatic chuck. The electrostatic chuck 30 may also be a Coulomb force type electrostatic chuck.

[0023] The adhesive layer 40 bonds the metal part 10 and the bush 20 to the electrostatic chuck 30. The adhesive layer 40 is in direct contact with the upper surface 10A of the metal part 10 and the upper surface 20A of the bush 20. That is, the upper surface 22A of the flange portion 22 is in direct contact with the adhesive layer 40. A primer may be placed between the lower surface 30B of the electrostatic chuck 30 and the adhesive layer 40. For example, a silicone resin-based adhesive is used as the material for the adhesive layer 40. The adhesive layer 40 contains silicone resin. The thickness of the adhesive layer 40 is, for example, 0.15 mm.

[0024] The power supply pin 50 is provided in the first through hole 18 and the second through hole 28 and is fixed to the electrode pad 33. The power supply pin 50 is fixed to the electrode pad 33 using, for example, a conductive adhesive or solder. The power supply pin 50 is electrically connected to the electrode 32 via the electrode pad 33 and the via conductor 34. The electrode 32 is electrically connected to the adsorption power supply via the via conductor 34, the electrode pad 33 and the power supply pin 50. The power supply pin 50 is separated from the inner wall surface of the second through hole 28. The power supply pin 50 has, for example, a linear conductor (not shown) and an insulator (not shown) that covers the radial side of the conductor. The power supply pin 50 is an example of a terminal.

[0025] The sleeve 70 is provided between the inner wall surface of the second through-hole 28 of the bush 20 and the outer surface of the power supply pin 50. For example, the sleeve 70 has a cylindrical shape. The sleeve 70 is mainly composed of, for example, polyetherimide resin. The sleeve 70 is an example of a second insulating member.

[0026] In the substrate fixing device 1 configured in this way, as described above, a predetermined voltage is applied to the electrode 32 from the suction power supply to adsorb and hold the substrate W on the upper surface 30A.

[0027] [Manufacturing method for substrate fixing device] Next, a method for manufacturing the substrate fixing device 1 according to the embodiment will be described. Figure 4 is a flowchart illustrating the method for manufacturing the substrate fixing device 1 according to the embodiment. Figures 5 to 7 are cross-sectional views illustrating the method for manufacturing the substrate fixing device 1 according to the embodiment.

[0028] First, as shown in Figure 5(a), a metal part 10 is prepared, which has a base plate 11, a heater 12, and an adhesive layer 13, and has a first through hole 18 and a recess 60 formed therein (Step S1). Next, a bush 20 is inserted into the recess 60 (Step S2).

[0029] Next, as shown in Figure 5(b), liquid adhesive 41 is applied to the upper surface 10A of the metal part 10 and the upper surface 20A of the bush 20 (step S3). The adhesive 41 contains silicone resin and hardens to form an adhesive layer 40. Note that no primer is applied to the upper surface 10A of the metal part 10 and the upper surface 20A of the bush 20 before applying the adhesive 41. Therefore, the upper surfaces 10A and 20A come into direct contact with the adhesive 41.

[0030] Next, as shown in Figure 6(a), the sleeve 70 is inserted into the second through-hole 28 of the bush 20 (step S4).

[0031] In addition, an electrostatic chuck 30 is prepared separately from the metal part 10 (step S5). Then, as shown in Figure 6(b), the electrostatic chuck 30 is bonded to the metal part 10 while its lower surface 30B is in contact with the liquid adhesive 41 (step S6). Before bonding the electrostatic chuck 30, a primer may be applied to the lower surface 30B of the electrostatic chuck 30.

[0032] Next, as shown in Figure 7(a), the adhesive 41 is cured (step S7) to form an adhesive layer 40. The adhesive layer 40 is in direct contact with the upper surface 10A and the upper surface 20A.

[0033] Next, as shown in Figure 7(b), the power supply pin 50 is inserted into the first through hole 18 and the second through hole 28, and the power supply pin 50 is fixed to the electrode pad 33 (step S8).

[0034] In this way, the substrate fixing device 1 can be manufactured.

[0035] Here, the effects of the substrate fixing device 1 will be explained in comparison with the comparative example. Figure 8 is a cross-sectional view illustrating a substrate fixing device according to the comparative example.

[0036] In the comparative example substrate fixing device 1X, a recess 60X is formed on the upper surface 10A of the metal part 10 in place of the recess 60. The recess 60X has a portion corresponding to the first recess 61, but does not have a portion corresponding to the second recess 62. On the upper surface 10A, the edge of the recess 60X is about 1.9 mm away from the center of the first through hole 18.

[0037] The substrate fixing device 1X has a bush 20X instead of a bush 20. The bush 20X is provided in the recess 60X. The bush 20X has a portion corresponding to the base 21 but does not have a portion corresponding to the flange 22. The bush 20X is mainly composed of polyetheretherketone (PEEK) resin. A primer 42X is provided on the upper surface of the bush 20X. The primer 42X is provided between the bush 20X and the adhesive layer 40. The thickness of the adhesive layer 40 is 0.076 mm.

[0038] The other components of the substrate fixing device 1X are the same as those of the substrate fixing device 1.

[0039] In substrate fixing device 1, the edge of the recess 60 is further from the center of the first through hole 18 than the edge of the recess 60X, the bush 20 has a flange portion 22, and the adhesive layer 40 is thicker than the adhesive layer 40 in substrate fixing device 1X. Therefore, the creepage distance from the tip of the power supply pin 50 connected to the electrode pad 33 to the upper surface 10A of the metal component 10 is longer in substrate fixing device 1 than in substrate fixing device 1X. For example, while the creepage distance in substrate fixing device 1X is about 2.4 mm, the creepage distance in substrate fixing device 1 can be increased to about 5.2 mm, which is about 2.17 times greater.

[0040] Furthermore, in the substrate fixing device 1X, a primer 42X is provided because the adhesive strength between the bush 20X, which is mainly composed of PEEK, and the adhesive layer 40 is low. In contrast, since the adhesive strength between the bush 20 containing zirconia and the adhesive layer 40 is high, a primer is not provided in the substrate fixing device 1. During the manufacturing process of the substrate fixing device 1X, the primer is applied to the upper surface of the bush 20X after it is inserted into the recess 60X. However, if there are areas on the upper surface of the bush 20X where the primer is not applied due to insufficient application, the desired adhesive strength may not be obtained. Conversely, if the primer 42X is applied excessively to the upper surface 10A of the metal part 10, the adhesive strength between the metal part 10 and the adhesive layer 40 will decrease. Thus, when the primer 42X is used, there is a risk that sufficient adhesive strength may not be obtained due to an excess or deficiency in the amount applied, but the substrate fixing device 1 can avoid the reduction in adhesive strength caused by the primer.

[0041] Here, we will describe the tensile shear test on adhesive strength conducted by the present inventor. Figure 9 is an example diagram illustrating the outline of the tensile shear test. Figure 9(a) is a perspective view, and Figure 9(b) is a cross-sectional view.

[0042] In the tensile shear test, a test specimen 80 was prepared by bonding a plate-shaped alumina material 81 to a plate-shaped material to be bonded 83 using an adhesive layer 82. The alumina material 81 and the material to be bonded 83 were bonded in a rectangular area of ​​25 mm × 15 mm in plan view. A primer 84 was placed between the adhesive layer 82 and the alumina material 81, and in some test specimens 80, a primer 85 was placed between the adhesive layer 82 and the material to be bonded 83. The material to be bonded 83 was made of three types: aluminum, PEEK, and zirconia.

[0043] The tensile load was applied to the plate surface of specimen 80 in a direction parallel to the surface (indicated by the arrow). The tensile speed was 1 mm / min. The tensile shear test was performed at room temperature. The tensile shear stress was measured three times for each condition, and the average value was calculated. The results of the tensile shear test are shown in Table 1 below.

[0044] [Table 1]

[0045] As shown in Table 1, under conditions No. 2, No. 3, and No. 5, the tensile shear stress is 0.28 MPa or higher, while under conditions No. 1 and No. 4, the tensile shear stress is 0.08 MPa or lower.

[0046] The lower tensile shear stress in condition No. 1 compared to condition No. 2 indicates that when the metal part 10 is made of aluminum, the adhesive strength decreases when the primer adheres to the metal part 10. The lower tensile shear stress in condition No. 4 compared to condition No. 3 indicates that when the bush 20X is made of PEEK, the adhesive strength decreases if there is a portion between the bush 20X and the adhesive layer 40 where the primer is not applied. The higher tensile shear stress in condition No. 5 compared to conditions No. 2 and No. 3 indicates that when the bush 20 is made of zirconia, sufficient adhesive strength can be obtained even without a primer.

[0047] Thus, according to the substrate fixing device 1 of this embodiment, the creepage distance from the tip of the power supply pin 50 connected to the electrode pad 33 to the upper surface 10A of the metal component 10 is long, which reduces discharge.

[0048] Furthermore, because the bush 20 contains zirconia, high adhesive strength can be obtained between the bush 20 and the adhesive layer 40 even without a primer between them. The absence of a primer between the bush 20 and the adhesive layer 40 prevents primer from adhering to the upper surface 10A of the metal component 10, thus preventing a decrease in adhesive strength due to primer adhesion. Therefore, the substrate fixing device 1 can stably obtain high adhesive strength between the electrostatic chuck 30 and the metal component 10 and bush 20. Consequently, delamination due to a decrease in adhesive strength can be prevented, and discharge through delaminate areas can be reduced.

[0049] The thickness of the adhesive layer 40 is preferably 0.10 mm or more and 0.20 mm or less. A thickness of 0.10 mm or more in the adhesive layer 40 makes it easier to reduce discharge. On the other hand, if the thickness of the adhesive layer 40 exceeds 0.20 mm, the thermal conductivity between the metal part 10 and the electrostatic chuck 30 may decrease.

[0050] Although preferred embodiments have been described in detail above, this disclosure is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims. [Explanation of Symbols]

[0051] 1 Board fixing device 10 Metal parts 10A top 10B Bottom 11 Base Plate 12 Heaters 18 First through hole 20 bush 20A top 21 Base 22 Guard section 22A Top 22B Bottom 28 Second through hole 30 Electrostatic Chuck 30B Bottom 40 Adhesive layer 50 power supply pins 60 recesses 61 First recess 62 Second recess 70 sleeves W board

Claims

1. A metal part having a first surface and a second surface opposite to the first surface, with a first through-hole formed that reaches the first surface and the second surface, and a recess surrounding the first through-hole formed on the first surface in a plan view, A cylindrical first insulating member containing zirconia, provided in the recess and having a second through-hole that communicates with the first through-hole, An electrostatic chuck having a third surface opposite to the first surface, a base body, and electrodes embedded in the base body, An adhesive layer for bonding the metal part, the first insulating member, and the electrostatic chuck, A terminal provided in the first through hole and the second through hole and electrically connected to the electrode, It has, The aforementioned recess is A first recess communicating with the first through hole, A second recess, which is shallower than the first recess and extends away from the first through hole, It has, The first insulating member is, A base portion provided in the first recess and having the second through hole formed therein, A flange portion is provided in the second recess and extends from the base portion in a direction away from the second through hole, A substrate fixing device having the following features.

2. The substrate fixing apparatus according to claim 1, wherein the first insulating member contains zirconia with a purity of 94% by mass or more.

3. The substrate fixing device according to claim 2, wherein the portion of the metal part having the first surface is made of aluminum or an aluminum alloy.

4. The substrate fixing apparatus according to any one of claims 1 to 3, wherein the adhesive layer contains a silicone resin.

5. The aforementioned metal part is A base plate having the second surface, A heater having the first surface and bonded to the base plate, It has, The substrate fixing device according to any one of claims 1 to 3, wherein the second recess is formed in the heater.

6. The aforementioned flange portion is The fourth surface in contact with the adhesive layer, A fifth surface that contacts the heater on the opposite side of the fourth surface, A substrate fixing device according to claim 5, having the following features.

7. The substrate fixing apparatus according to any one of claims 1 to 3, wherein the substrate contains alumina.

8. The substrate fixing device according to any one of claims 1 to 3, wherein the thickness of the adhesive layer is 0.10 mm or more and 0.20 mm or less.

9. A substrate fixing device according to any one of claims 1 to 3, further comprising a second insulating member provided between the first insulating member and the terminal.

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