Holding device

Abstract

To provide a holding device capable of preventing occurrence of defective joining in a base member composed of a plurality of substrates and improving cooling performance of a plate-shaped member by a refrigerant.SOLUTION: One aspect of the present disclosure relates to an electrostatic chuck 1 in which a base member 20 is formed by joining a plurality of substrates 41 via a metal joining layer 42. On one of an upper surface 51 positioned on a ceramics plate 10 side or a lower surface 52 positioned on an opposite side of the upper surface 51 in a thickness direction among inner surfaces of a refrigerant flow path 23, there are formed a contact portion 61 in contact with the metal joining layer 42 at a boundary between the substrate 41 and the metal joining layer 42, and a cutout portion 62 penetrating the metal joining layer 42.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] The semiconductor manufacturing member (holding device) disclosed in Patent Document 1 includes a plate-shaped member having a wafer mounting surface, and a cooling plate (base member) having a refrigerant flow path therein, which is joined to the plate-shaped member on the side opposite to the wafer mounting surface in the thickness direction. This cooling plate is made of multiple substrates joined together via metal bonding layers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5666749 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the semiconductor manufacturing member disclosed in Patent Document 1, the entire upper surface of the refrigerant flow path of the cooling plate is covered with a metal bonding layer, which may result in a deterioration in the cooling performance of the plate-shaped member by the refrigerant compared to when the entire upper surface of the refrigerant flow path is not covered with a metal bonding layer.

[0005] On the other hand, if the entire upper surface of the refrigerant flow path is not covered with the metal bonding layer, there is a risk that the refrigerant will leak from the unbonded parts that are not covered with the metal bonding layer, and there is also a risk that peeling will occur between the substrate and the metal bonding layer, starting from the unbonded parts.

[0006] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a holding device that can prevent poor bonding in a base member composed of multiple substrates and improve the cooling performance of plate-shaped members using a refrigerant. [Means for solving the problem]

[0007] One form of the present disclosure made to solve the above problem is a holding device having a plate-shaped member having a first surface and a second surface opposite the first surface in a thickness direction, and a base member having a refrigerant flow path for flowing a refrigerant therein and joined to the plate-shaped member on the second surface side, and holding an object on the first surface, characterized in that the base member is formed by joining multiple substrates via a metal bonding layer, and a contact portion that contacts the metal bonding layer at the boundary between the substrate and the metal bonding layer and a notch that penetrates the metal bonding layer are formed on either a third surface located on the plate-shaped member side of the inner surface of the refrigerant flow path or a fourth surface located opposite the third surface in the thickness direction.

[0008] According to this aspect, by forming a contact portion that contacts the metal bonding layer at the boundary between the substrate and the metal bonding layer and a notch that penetrates the metal bonding layer on either the third or fourth surface of the inner surface of the refrigerant flow path, the notch prevents a gap from forming between the substrate and the metal bonding layer, and the contact portion firmly bonds the substrates together even in the area where the refrigerant flow path exists (i.e., ensures the required bonding strength). This prevents a decrease in the bonding strength between the substrates that make up the base member. Furthermore, if a metal bonding layer exists between the refrigerant flow path and the plate-like member, the notch prevents a deterioration in the cooling performance of the plate-like member by the refrigerant. This prevents bonding defects in a base member made up of multiple substrates and improves the cooling performance of the plate-like member by the refrigerant.

[0009] In the above aspect, it is preferable that the contact portion and the notch portion are formed only on the fourth surface of the refrigerant flow path.

[0010] According to this aspect, since there is no metal bonding layer between the coolant flow path and the plate-like member, the cooling performance of the plate-like member by the coolant can be further improved.

[0011] In the above aspect, it is preferable that the contact portion and the notch portion are formed on both the third surface and the fourth surface of the refrigerant flow path.

[0012] According to this aspect, even when metal bonding layers are present on both the third and fourth surfaces of the refrigerant flow path, poor bonding in the base member can be prevented and the cooling performance of the plate-shaped member by the refrigerant can be improved. [Effects of the Invention]

[0013] The holding device of the present disclosure can prevent poor bonding in a base member made up of multiple substrates, and can also improve the cooling performance of the plate-like members by the refrigerant. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic perspective view of an electrostatic chuck. [Figure 2] 1 is a schematic diagram of an XZ cross section (partially an external view) of an electrostatic chuck according to a first embodiment. [Figure 3] 3 is an enlarged cross-sectional view of a refrigerant flow path and its periphery in a region α of FIG. 2. FIG. [Figure 4] FIG. 10 is a schematic diagram of an XZ cross section (partially an external view) of an electrostatic chuck according to a second embodiment. [Figure 5] 5 is an enlarged cross-sectional view of a refrigerant flow path and its periphery in a region β of FIG. 4. [Figure 6] FIG. 10 is an enlarged cross-sectional view of a refrigerant flow path and its periphery in a first modified example. [Figure 7] FIG. 10 is an enlarged cross-sectional view of a coolant flow path and its periphery in a second modified example. [Figure 8] FIG. 11 is an enlarged cross-sectional view of a refrigerant flow path and its periphery in a third modified example. [Figure 9] FIG. 10 is an enlarged cross-sectional view of a refrigerant flow path and its periphery in a comparative example. [Figure 10] FIG. 10 is an enlarged cross-sectional view of a refrigerant flow path and its periphery in another comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0015] A holding device according to the present disclosure will be described. In this embodiment, the holding device will be described by taking as an example an electrostatic chuck used in semiconductor manufacturing equipment such as a film forming apparatus (such as a CVD film forming apparatus or a sputtering film forming apparatus) or an etching apparatus (such as a plasma etching apparatus).

[0016] <Explanation of electrostatic chuck> First, the electrostatic chuck 1 of this embodiment will be described.

[0017] The electrostatic chuck 1 is a device that attracts and holds a semiconductor wafer W by electrostatic attraction, and is used, for example, to fix the semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing device. The semiconductor wafer W is an example of the "target object" in this disclosure.

[0018] 1, the electrostatic chuck 1 includes a ceramic plate 10, a base member 20, and a bonding layer 30 that bonds the ceramic plate 10 to the base member 20. The ceramic plate 10 is an example of the "plate-like member" of the present disclosure.

[0019] In the following description, for convenience of explanation, X, Y, and Z axes are defined as shown in Fig. 1. Here, the Z axis is an axis in the axial direction of the electrostatic chuck 1 (the vertical direction in Fig. 1), and the X and Y axes are axes in the radial direction of the electrostatic chuck 1.

[0020] As shown in Fig. 1, the ceramic plate 10 is a disk-shaped member made of ceramic. Various ceramics can be used to form the ceramic plate 10, but from the viewpoints of strength, wear resistance, plasma resistance, etc., it is preferable to use ceramics whose main component is, for example, aluminum oxide (alumina, Al2O3) or aluminum nitride (AlN). Note that the term "main component" here refers to the component with the highest content (for example, a component with a volume content of 90 vol% or more).

[0021] 1 and 2, the ceramic plate 10 has a holding surface 11 (upper surface) that holds the semiconductor wafer W, and a lower surface 12 that is provided on the opposite side of the holding surface 11 in the thickness direction (i.e., the Z-axis direction) of the ceramic plate 10. The holding surface 11 is an example of a "first surface" in the present disclosure. The lower surface 12 is an example of a "second surface" in the present disclosure.

[0022] Here, the diameter of the ceramic plate 10 is, for example, about 150 mm to 300 mm. The thickness of the ceramic plate 10 is, for example, about 1 mm to 6 mm. The thermal conductivity of the ceramic plate 10 is preferably in the range of 10 W / mK to 170 W / mK (more preferably, 18 W / mK to 33 W / mK).

[0023] The ceramic plate 10 includes a chuck electrode (not shown) therein. When a voltage is applied to the chuck electrode, an electrostatic attraction (adsorption force) is generated on the holding surface 11, and the semiconductor wafer W is attracted and fixed to the holding surface 11 by this electrostatic attraction.

[0024] 1, the base member 20 is disposed on the opposite side of the ceramic plate 10 from the holding surface 11. The base member 20 is formed, for example, in a cylindrical shape. The base member 20 is formed, for example, from a metal (for example, an aluminum alloy, a titanium alloy, or a molybdenum alloy), but may also be formed from a material other than a metal, such as a ceramic (for example, SiC) or a metal-ceramic composite material (for example, an Al / SiC composite material, a Ti / SiC composite material, or the like).

[0025] 1 and 2, the base member 20 has an upper surface 21 and a lower surface 22 provided on the opposite side to the upper surface 21 in the thickness direction of the base member 20 (i.e., the Z-axis direction). The upper surface 21 of the base member 20 is thermally connected to the lower surface 12 of the ceramic plate 10 via a bonding layer 30. The base member 20 also has a refrigerant flow path 23 therein for flowing a refrigerant (e.g., a fluorine-based inert liquid, water, etc.). When viewed from the thickness direction of the base member 20, the refrigerant flow path 23 is formed, for example, in a spiral shape across the entire holding surface 11 of the ceramic plate 10.

[0026] 2, the base member 20 of this embodiment is formed by bonding a plurality of substrates 41 (for example, a first substrate 41A and a second substrate 41B) via a metal bonding layer 42. Such a base member 20 is formed, for example, by bonding the second substrate 41B via the metal bonding layer 42 to the first substrate 41A, in which the refrigerant flow path 23 has been formed in advance.

[0027] The diameter of the base member 20 is, for example, about 180 mm to 400 mm. The thickness (dimension in the Z-axis direction) of the base member 20 is, for example, about 20 mm to 50 mm. The thermal conductivity of the base member 20 (assumed to be made of aluminum) is preferably within a range of 160 W / mK to 250 W / mK (preferably, about 230 W / mK). The thermal conductivity of the base member 20 (assumed to be made of SiC) is preferably within a range of 130 W / mK to 200 W / mK (preferably, about 170 W / mK). Furthermore, when the base member 20 is a metal-ceramic composite member, the thermal conductivity is preferably within a range of 70 W / mK to 220 W / mK (preferably, about 100 W / mK). Details of the base member 20 will be described later.

[0028] As shown in FIGS. 1 and 2 , the bonding layer 30 is disposed between the lower surface 12 of the ceramic plate 10 and the upper surface 21 of the base member 20, and bonds the ceramic plate 10 and the base member 20 in a heat-transferable manner. The bonding layer 30 is formed of a metal such as an aluminum alloy or an indium alloy. The thickness (dimension in the Z-axis direction) of the bonding layer 30 is, for example, approximately 0.1 mm to 1.5 mm. The thermal conductivity of the bonding layer 30 is, for example, 170 W / mK. The thermal conductivity of the bonding layer 30 (assumed to be metal) is preferably within a range of 70 W / mK to 220 W / mK (preferably, approximately 130 W / mK to 200 W / mK). By thus metal-bonding the ceramic plate 10 and the base member 20 with the bonding layer 30, heat from the ceramic plate 10 can be efficiently transferred to the base member 20.

[0029] In the bonded body of the above configuration, the difference between the thermal expansion coefficient of the base member 20 and the thermal expansion coefficient of the ceramic plate 10 is, for example, 1×10 -6 / K (assuming a ceramic or ceramic-metal composite member). With this configuration, even if the bonding layer 30 is made of a highly rigid metal material, the ceramic plate 10 and the base member 20 can be bonded without peeling off.

[0030] The bonding layer 30 may be made of a resin adhesive such as a silicone resin, an acrylic resin, or an epoxy resin. In this case, the thermal conductivity of the bonding layer 30 is, for example, 1.0 W / mK, and the thermal conductivity of the bonding layer 30 (assumed to be a silicone resin) is preferably in the range of 0.1 W / mK to 2.0 W / mK (preferably, 0.5 W / mK to 1.5 W / mK).

[0031] <Details of the base material> Next, the base member 20 of this embodiment will be described in detail.

[0032] The base member 20 of this embodiment is formed by bonding a plurality of substrates 41 together via metal bonding layers 42. The substrates 41 are made of, for example, ceramics (e.g., SiC) or a composite material such as a metal-ceramic composite material (e.g., Al / SiC composite material, Ti / SiC composite material, etc.). The metal bonding layers 42 are made of a brazing filler metal (e.g., aluminum alloy, indium alloy, etc.).

[0033] (First Example) First, a description will be given of Example 1. In this example, as shown in Fig. 2, a base member 20 includes two substrates 41 (i.e., a first substrate 41A and a second substrate 41B) bonded together via a metal bonding layer 42.

[0034] 9, a comparative example is assumed in which the entire lower surface 52 of the refrigerant flow path 23 is not covered with the metal bonding layer 42, and the metal bonding layer 42 is present only on a portion (i.e., the lower end) of the side surface 53 of the refrigerant flow path 23. In this case, in the portion of the lower surface 52 of the refrigerant flow path 23 where the metal bonding layer 42 is not present, the refrigerant may leak from the boundary between the two substrates 41 and the metal bonding layer 42 to the outside of the refrigerant flow path 23. Furthermore, there is a risk that the bonded portion between the substrates 41 and the metal bonding layer 42 may peel off, starting from the portion of the lower surface 52 of the refrigerant flow path 23 where the metal bonding layer 42 is not present.

[0035] In another comparative example, when the entire lower surface 52 of the refrigerant flow path 23 is covered with the metal bonding layer 42, if pressure is applied to the metal bonding layer 42 when joining the multiple substrates 41, the second substrate 41B and the metal bonding layer 42 may not be bonded properly, and a gap δ may occur between the second substrate 41B and the metal bonding layer 42. When the gap δ occurs, the metal bonding layer 42 is not in close contact with the substrate 41B, as shown in FIG. 10 . This reduces the heat transfer in the area where the gap δ occurs.

[0036] Therefore, in this embodiment, as shown in Figure 3, a contact portion 61 that contacts the metal bonding layer 42 at the boundary between the second substrate 41B and the metal bonding layer 42, and a notch portion 62 that penetrates the metal bonding layer 42 are formed only on the lower surface 52 of the inner surface of the refrigerant flow path 23.

[0037] The lower surface 52 is an inner surface of the refrigerant flow path 23 that is located on the opposite side to the upper surface 51 in the thickness direction of the base member 20 (i.e., the Z-axis direction), and is an example of a "fourth surface" in the present disclosure. The upper surface 51 is an inner surface of the refrigerant flow path 23 that is located on the ceramic plate 10 side in the thickness direction of the base member 20, and is an example of a "third surface" in the present disclosure.

[0038] In this way, the metal bonding layer 42 is not formed on the upper surface 51 of the refrigerant flow path 23, while the metal bonding layer 42 is formed on the lower surface 52 of the refrigerant flow path 23. The metal bonding layer 42 is formed so as to protrude (i.e., project) into the refrigerant flow path 23 from the lower end portions of the side surfaces 53 on both the left and right sides of the refrigerant flow path 23 (i.e., both sides in the X-axis direction).

[0039] In this way, notch 62 prevents the formation of gap δ, and contact portion 61 firmly bonds the substrates together even in the area where refrigerant flow path 23 is present (i.e., the required bonding strength can be ensured). This prevents a decrease in the bonding strength between substrates 41 (i.e., first substrate 41A and second substrate 41B) that constitute base member 20. The amount of protrusion of metal bonding layer 42 from side surface 53 into refrigerant flow path 23 is preferably 0.5 to 30% on one side of the width of refrigerant flow path 23, and more preferably 0.5 to 10%.

[0040] Furthermore, since the metal bonding layer 42 is not formed on the upper surface 51 of the refrigerant flow path 23, the metal bonding layer 42 does not exist between the refrigerant flow path 23 and the ceramic plate 10, thereby improving the cooling performance of the ceramic plate 10 by the refrigerant.

[0041] Therefore, it is possible to prevent bonding defects from occurring in the base member 20 formed of the two substrates 41 (i.e., the first substrate 41A and the second substrate 41B), and to improve the cooling performance of the ceramic plate 10 by the refrigerant.

[0042] (Second Example) Next, a second embodiment will be described. In this embodiment, as shown in Fig. 4, the base member 20 has three substrates 41 (i.e., a first substrate 41A, a second substrate 41B, and a third substrate 41C) bonded together via two metal bonding layers 42 (i.e., a first metal bonding layer 42A and a second metal bonding layer 42B). As shown in Figs. 4 and 5, the metal bonding layers 42 are present on both the upper surface 51 and the lower surface 52 of the refrigerant flow path 23. That is, the first metal bonding layer 42A is present on the upper surface 51, and the second metal bonding layer 42B is present on the lower surface 52.

[0043] As shown in FIG. 5, a contact portion 61 and a notch 62 are formed on both the upper surface 51 and the lower surface 52 of the refrigerant flow path 23, respectively.

[0044] In this way, when the metal bonding layer 42 exists on both the upper surface 51 and the lower surface 52 of the refrigerant flow path 23, the contact portions 61 are formed on both the upper surface 51 and the lower surface 52, respectively, thereby preventing poor bonding in the base member 20. Furthermore, the cutout portions 62 are formed on both the upper surface 51 and the lower surface 52, respectively, so that the ceramic plate 10 can be cooled via the cutout portions 62, thereby improving the cooling performance of the ceramic plate 10 by the refrigerant.

[0045] (Variation) In the present disclosure, it is sufficient that the contact portion 61 and the notch portion 62 are formed on either the upper surface 51 or the lower surface 52 of the inner surface of the refrigerant flow path 23.

[0046] Therefore, as a first variant, when the base member 20 is formed by joining two substrates 41 via a metal bonding layer 42, as shown in Figure 6, the entire lower surface 52 of the inner surface of the refrigerant flow path 23 is not covered by the metal bonding layer 42, while a contact portion 61 and a cutout portion 62 may be formed only on the upper surface 51.

[0047] This allows the ceramic plate 10 to be cooled by the refrigerant in the refrigerant flow path 23 through the notch 62 formed in the upper surface 51, thereby improving the cooling performance of the ceramic plate 10 by the refrigerant.

[0048] In addition, as a second variant, when the base member 20 is formed by joining three substrates 41 via a metal bonding layer 42, as shown in Figure 7, of the inner surface of the refrigerant flow path 23, the entire upper surface 51 is covered and in contact with the first metal bonding layer 42A, while a contact portion 61 and a cutout portion 62 may be formed only on the lower surface 52.

[0049] Furthermore, as a third variant, when the base member 20 is formed by joining three substrates 41 via a metal bonding layer 42, as shown in Figure 8, the entire lower surface 52 of the inner surface of the refrigerant flow path 23 may be covered by and in contact with the second metal bonding layer 42B, while a contact portion 61 and a cutout portion 62 may be formed only on the upper surface 51.

[0050] It should be noted that the above-described embodiments are merely examples and do not limit the present disclosure in any way. It goes without saying that various improvements and modifications are possible within the scope of the gist thereof. [Explanation of symbols]

[0051] 1. Electrostatic chuck 10 Ceramic plate 11 Holding surface 20 Base member 23 Refrigerant flow path 30 Bonding layer 41 PCB 41A First board 41B Second board 41C 3rd base plate 42 Metal bonding layer 42A First Metal Bonding Layer 42B Second Metal Bonding Layer 51 Above 52 Below 61 Contact Department 62 Cut off part δ void W semiconductor company

Claims

1. a plate-like member having a first surface and a second surface provided on the opposite side of the first surface in a thickness direction; a base member having a refrigerant flow path therein for allowing a refrigerant to flow, the base member being joined to the plate-like member on the second surface side; A holding device for holding an object on the first surface, the base member is formed by bonding a plurality of substrates together via a metal bonding layer; a contact portion that contacts the metal bonding layer at the boundary between the substrate and the metal bonding layer, and a notch that penetrates the metal bonding layer, are formed on either a third surface that is located on the plate-like member side of the inner surface of the coolant flow path or a fourth surface that is located on the opposite side to the third surface in the thickness direction; A holding device characterized by:

2. 2. The holding device according to claim 1, the contact portion and the notch portion are formed only on the fourth surface of the refrigerant flow path; A holding device characterized by:

3. 2. The holding device according to claim 1, the contact portion and the notch portion are formed on both the third surface and the fourth surface of the refrigerant flow path, respectively; A holding device characterized by:

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