Holding device

Abstract

To secure the contact area between a thermal conductive gas to be introduced into a gas flow channel and a porous body.SOLUTION: A holding device 1 includes a holding substrate 10 including a plate-shaped member 11 mainly containing ceramics and having a first surface S1 and a second surface S2 on the opposite side of the first surface S1, a gas flow channel formed inside the plate-shaped member 11, and a porous body 70 with a gas transmitting property filling a part of the gas flow channel and mainly containing ceramics. The gas flow channel includes a longitudinal flow channel part including a gas outlet 12B opening on the first surface S1 side and extending from the gas outlet 12B to the second surface S2 side, and a lateral flow channel part 14 connected to the longitudinal flow channel part and extending in parallel to the first surface S1. The porous body 70 has a bottom surface 70B on the second surface S2 side, and fills the longitudinal flow channel part. The lateral flow channel part 14 includes a space 15 right below the porous body that is disposed on the second surface S2 side with respect to the porous body 70. The area of the space 15 right below the porous body in a plan view is larger than the area of the bottom surface 70B in the plan view.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] As an example of a holding device for holding a wafer (semiconductor wafer) when manufacturing a semiconductor, an electrostatic chuck can be mentioned (see Patent Document 1). The electrostatic chuck includes a holding substrate (ceramic substrate) mainly made of an insulating ceramic (for example, alumina), and the wafer is held on the surface of the holding substrate by electrostatic attraction. The electrostatic attraction is generated by applying a voltage to a chuck electrode provided inside the holding substrate.

[0003] In this type of electrostatic chuck, in plasma processing such as plasma etching, a heat transfer gas such as helium gas is supplied between the holding substrate and the wafer to remove heat from the wafer. Therefore, a gas flow path for flowing the heat transfer gas supplied from the outside toward the wafer is formed inside the holding substrate of the electrostatic chuck.

[0004] Note that abnormal discharge (arcing) may occur in the gas flow path due to the high-frequency power applied during plasma processing, and the wafer on the holding substrate may be damaged by the abnormal discharge. Therefore, in order to suppress the occurrence of such abnormal discharge, a gas-permeable porous body made of an insulating ceramic material is provided inside the gas flow path.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In a conventional holding device, in order to ensure the supply amount of the heat-conducting gas from the surface of the holding substrate, it is important to increase the contact area between the heat-conducting gas introduced into the gas flow path and the surface of the porous body.

[0007] The present disclosure has been completed based on the above circumstances, and aims to ensure the contact area between the heat-conducting gas introduced into the gas flow path and the porous body.

Means for Solving the Problems

[0008] The holding device of the present disclosure includes a first surface and a second surface disposed on the opposite side of the first surface, a plate-like member mainly composed of ceramics, a gas flow path formed inside the plate-like member, and a gas-permeable porous body mainly composed of ceramics filled in a part of the gas flow path. The holding device includes a holding substrate, wherein the gas flow path includes a gas outlet opening to the first surface side, a vertical flow path portion extending from the gas outlet to the second surface side, and a horizontal flow path portion connected to the vertical flow path portion and extending parallel to the first surface. The porous body has a bottom surface on the second surface side and is filled in the vertical flow path portion. The horizontal flow path portion has a porous directly below space disposed on the second surface side with respect to the porous body, and the area of the porous directly below space in plan view is larger than the area of the bottom surface in plan view.

Effects of the Invention

[0009] According to the present disclosure, the contact area between the heat-conducting gas introduced into the gas flow path and the porous body can be ensured.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

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Figure 13

BEST MODE FOR CARRYING OUT THE INVENTION

[0011] [Description of Embodiments of the Present Disclosure] First, the embodiments of the present disclosure will be listed and described. (1) The holding device of the present disclosure includes a first surface and a second surface disposed on the opposite side of the first surface, a plate-like member mainly composed of ceramics, a gas flow path formed inside the plate-like member, and a gas-permeable porous body mainly composed of ceramics filled in a part of the gas flow path. The holding device includes a holding substrate, wherein the gas flow path includes a gas flow outlet opened on the first surface side, a vertical flow path portion extending from the gas flow outlet to the second surface side, and a horizontal flow path portion connected to the vertical flow path portion and extending parallel to the first surface. The porous body has a bottom surface on the second surface side and is filled in the vertical flow path portion. The horizontal flow path portion has a porous directly-below space disposed on the second surface side with respect to the porous body, and the area of the porous directly-below space in a plan view is larger than the area of the bottom surface in the plan view.

[0012] According to such a configuration, it is possible to suppress a part of the bottom surface of the porous body from being blocked by a part of the plate-like member, and it is possible to secure the contact area between the heat-conductive gas introduced into the gas flow path and the porous body.

[0013] (2) In the holding device according to (1), it is preferable that the porous directly-below space has a central space overlapping the bottom surface in a plan view and a peripheral space disposed around the central space.

[0014] According to such a configuration, by providing the peripheral space, it becomes easier to further suppress a part of the bottom surface of the porous body from being blocked by a part of the plate-like member.

[0015] (3) In the holding device according to (2), when the dimension in the direction perpendicular to the first surface is defined as the thickness, it is preferable that the thickness of the peripheral space is larger than the thickness of the central space.

[0016] According to such a configuration, since the volume of the horizontal flow path portion can be increased, it becomes easy to secure the flow rate of the heat-conductive gas.

[0017] (4) In the holding device described in (2), when the dimension in the direction orthogonal to the first surface is defined as the thickness, it is preferable that the thickness of the peripheral space is smaller than the thickness of the central space.

[0018] According to such a configuration, by reducing the volume of the cross-flow path portion, it becomes easier to suppress abnormal discharge in the cross-flow path portion.

[0019] (5) In the holding device described in (1), it is preferable that the porous body is arranged on the second surface side of the gas outlet and has a wide portion larger in the radial direction than the gas outlet.

[0020] According to such a configuration, by providing the wide portion, for example, when an external force is applied to the porous body, it becomes difficult for the porous body to fall off from the longitudinal flow path portion.

[0021] [Details of Embodiment 1 of the Present Disclosure] A specific example of Embodiment 1 of the present disclosure will be described with reference to FIGS. 1 to 8. It should be noted that the present disclosure is not limited to these examples, but is shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the following description, for a plurality of identical members, only some members may be labeled with reference numerals, and the reference numerals of other members may be omitted. In this specification, the vertical direction in the illustration of FIG. 2 is defined as the vertical direction, and the horizontal direction in the illustration of FIG. 2 is defined as the horizontal direction, and the configuration of the holding device 1 will be described. However, in the actual usage mode of the holding device 1, it may be arranged differently. Also, in this specification, "orthogonal" and "parallel" shall include arrangements in a manner that is substantially recognized as orthogonal or parallel.

[0022] The holding device 1 of the present embodiment is an electrostatic chuck 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 is attached to, for example, a processing chamber of a semiconductor manufacturing apparatus (not shown) and is used to perform various processes (film formation, etching, etc.) on the wafer W using plasma.

[0023] As shown in FIG. 1, the holding device 1 includes a holding substrate 10 and a base member 20. The holding substrate 10 has a disk shape and can be formed into a shape having a diameter of about 300 mm and a thickness of about 3 mm, for example. The base member 20 has a disk shape with a larger diameter than the holding substrate 10 and can be formed into a shape having a diameter of about 340 mm and a thickness of about 20 mm, for example. Note that the holding substrate 10 and the base member 20 may be provided with positioning portions (such as unevenness) for aligning their positions with each other.

[0024] The holding substrate 10 and the base member 20 are overlapped with each other in the vertical direction in a state where the holding substrate 10 is disposed on the upper side and the base member 20 is disposed on the lower side. The holding substrate 10 and the base member 20 are joined to each other by a joining material 30 interposed therebetween.

[0025] As shown in FIG. 2, the holding substrate 10 has a substantially circular first surface S1 disposed on the upper side, and a substantially circular second surface S2 disposed on the opposite side (i.e., the lower side) of the first surface S1 and facing the base member 20. The base member 20 has a substantially circular third surface S3 disposed on the upper side and facing the second surface S2 of the holding substrate 10, and a substantially circular fourth surface S4 disposed on the opposite side (i.e., the lower side) of the third surface S3. The above-described joining material 30 is sandwiched between the second surface S2 of the holding substrate 10 and the third surface S3 of the base member 20 and is in a state of spreading in a layer shape.

[0026] The holding substrate 10 has a disk-shaped plate member 11 and a substrate-side gas flow path 12 (an example of a gas flow path) formed inside the plate member 11. The upper surface of the plate member 11 becomes the first surface S1 of the holding substrate 10. Also, the lower surface of the plate member 11 becomes the second surface S2 of the holding substrate 10.

[0027] The plate member 11 is an insulating member having a plate shape (disk shape) mainly composed of ceramics. In this specification, the "main component" means the component having the largest content ratio. The plate member 11 of the present embodiment is alumina (Al 2 O 3It consists of

[0028] The substrate-side gas flow path 12 is a part of the flow path 60 formed in the holding device 1. A heat-conductive gas such as helium gas is flowed through the flow path 60. The substrate-side gas flow path 12 is formed inside the plate-like member 11 of the holding substrate 10. The substrate-side gas flow path 12 consists of a hole that penetrates the inside of the holding substrate 10 and includes an inlet 12A that opens to the second surface S2 of the holding substrate 10 and a gas flow outlet 12B that opens to the first surface S1. When the heat-conductive gas is supplied from the inlet 12A, the heat-conductive gas passes through the substrate-side gas flow path 12 and is finally discharged to the outside from the gas flow outlet 12B.

[0029] FIG. 3 is a cross-sectional view of the holding substrate 10 with a part of the substrate-side gas flow path 12 enlarged, and FIG. 4 is a cross-sectional view taken along line A-A of FIG. 3. FIG. 3 shows a cross-sectional structure obtained by cutting the holding substrate 10 along the thickness direction. As shown in FIG. 3, the substrate-side gas flow path 12 has a first vertical flow path portion 13 (an example of a vertical flow path portion), a horizontal flow path portion 14, and a second vertical flow path portion 17.

[0030] The first vertical flow path portion 13 includes the gas flow outlet 12B that opens to the first surface S1 side, and extends in the thickness direction (vertical direction) of the plate-like member 11 from the gas flow outlet 12B to the second surface S2 side. The first vertical flow path portion 13 includes an opening 12C that is the inlet of the first vertical flow path portion 13 on the side opposite to the gas flow outlet 12B. The opening 12C is provided with substantially the same diameter as the gas flow outlet 12B. Note that the first vertical flow path portion 13 consists of a section between the gas flow outlet 12B and the opening 12C in the substrate-side gas flow path 12.

[0031] Inside the first vertical flow path portion 13, a porous body 70 is filled. The porous body 70 is a gas-permeable member containing a large number of pores and mainly composed of insulating ceramics. The porous body 70 is filled in each of the plurality of first vertical flow path portions 13 in the substrate-side gas flow path 12. As a whole, the porous body 70 has a columnar shape extending in the vertical direction (the thickness direction of the holding substrate 10). Inside the porous body 70, a ventilation path for passing an inert gas is formed in a network shape. The ventilation path is composed of a large number of pores connected to each other within the porous body 70. The pores are formed as traces where particulate pore-forming materials have burned out (disappeared) during the production (firing) of the porous body 70. As the pore-forming material, for example, beads made of synthetic resin, carbon powder, etc. are used.

[0032] The porous body 70 is filled in the first vertical flow path portion 13 in such a manner that the circular upper surface 70A is exposed from the gas outlet 12B and the circular bottom surface 70B is exposed to the cross-flow path portion 14 side from the opening 12C. In the case of this embodiment, the first surface S1 and the upper surface 70A are arranged to be in the same plane with each other. Also, the bottom surface 70B is parallel to the first surface S1 and is arranged at the same height as the opening 12C. Note that the porous body 70 and the inner peripheral surface constituting the first vertical flow path portion 13 are sintered and joined to each other.

[0033] The bottom surface 70B of the porous body 70 faces the cross-flow path portion 14, and the heat-conducting gas supplied from the upstream side of the substrate-side gas flow path 12 is supplied into the porous body 70 from this bottom surface 70B. The bottom surface 70B is porous, and the bottom surface 70B serves as an inlet for the heat-conducting gas.

[0034] The cross-flow path portion 14 is connected to the first vertical flow path portion 13 and extends parallel to the first surface S1. The downstream side of the cross-flow path portion 14 is connected to the opening 12C on the upstream side of the first vertical flow path portion 13. Note that in the substrate-side gas flow path 12, the inlet 12A side is the upstream side and the gas outlet 12B side is the downstream side.

[0035] As shown in FIG. 4, the cross-flow path portion 14 has a porous body directly below space 15 and a main body cross-flow path portion 16. The porous body directly below space 15 is located at the downstream end of the cross-flow path portion 14. The main body cross-flow path portion 16 connects between the porous body directly below space 15 and the second longitudinal flow path portion 17. An opening 15C that connects to the downstream side of the main body cross-flow path portion 16 is provided in the porous body directly below space 15.

[0036] The porous body directly below space 15 is arranged on the second surface S2 side (downward) with respect to the porous body 70 filled in the first longitudinal flow path portion 13. The porous body directly below space 15 is a substantially columnar space extending in the vertical direction. The area of the porous body directly below space 15 as viewed from the vertical direction is larger than the area of the bottom surface 70B of the porous body 70 as viewed from the vertical direction. In other words, the area of the porous body directly below space 15 in plan view is larger than the area of the bottom surface 70B of the porous body 70 in plan view. In FIGS. 4 and 5, the two-dot chain line indicates the outer shape of the bottom surface 70B. Further, this two-dot chain line indicates the boundary between the central space 15A and the peripheral space 15B described later.

[0037] The shape of the porous body directly below space 15 as viewed from the vertical direction is preferably a shape corresponding to the shape of the bottom surface 70B of the porous body 70 as viewed from the vertical direction. More specifically, the shape of the porous body directly below space 15 as viewed from the vertical direction is preferably a shape obtained by expanding the shape of the bottom surface 70B of the porous body 70 as viewed from the vertical direction. For example, in the present embodiment, the shape of the porous body directly below space 15 as viewed from the vertical direction and the shape of the bottom surface 70B of the porous body 70 as viewed from the vertical direction are substantially circular.

[0038] The space directly below the porous material has a central space 15A that overlaps with the bottom surface 70B when viewed from the top-bottom direction (in a plan view), and a peripheral space 15B that is disposed around the central space 15A. The peripheral space 15B spreads outward from the central space 15A in the horizontal direction relative to the central space 15A. As shown in FIG. 4, the center C1 of the bottom surface 70B in a plan view may coincide with the center C2 of the space directly below the porous material in a plan view. Also, as shown in FIG. 5, the center C1 of the bottom surface 70B in a plan view may be shifted from the center C2 of the space directly below the porous material in a plan view. It is preferable that the entire bottom surface 70B is disposed facing the space directly below the porous material 15.

[0039] The downstream side of the main body horizontal flow passage section 16 is connected to the opening 15C of the space directly below the porous material 15. The main body horizontal flow passage section 16 extends in an elongated shape parallel to the first surface S1. As shown in FIG. 3, the upstream side of the main body horizontal flow passage section 16 is connected to the second vertical flow passage section 17.

[0040] The second vertical flow path section 17 includes an inlet 12A that opens to the second surface S2, and extends from the inlet 12A to the first surface S1 in the thickness direction of the plate-like member 11. The downstream side of the second vertical flow path section 17 is connected to the upstream side of the horizontal flow path section 14. The inlet 12A forms the inlet of the substrate-side gas flow path 12.

[0041] The holding substrate 10 further includes a chuck electrode 40 which is an electrode member. The chuck electrode 40 is generally planar (layered) and generally parallel to the first surface S1. The chuck electrode 40 is made of a conductive material such as tungsten, molybdenum, or platinum. As shown in FIG. 2, the chuck electrode 40 is disposed on the first surface S1 side inside the holding substrate 10 (plate-like member 11). The chuck electrode 40 is connected to an external power source via a terminal or the like. When power is supplied to the chuck electrode 40, an electrostatic attraction is generated, and the wafer W is attracted and held on the first surface S1 of the holding substrate 10 by the electrostatic attraction. The chuck electrode 40 has a through hole 41 penetrating in the thickness direction (vertical direction). In other embodiments, a high-frequency electrode or a heater electrode may be provided as the electrode member.

[0042] As shown in FIGS. 1 and 2, a plurality of gas outlets 12B are provided on the first surface S1 of the holding substrate 10. The outer peripheral edge portion of the first surface S1 is formed in an annular shape while protruding slightly upward compared to the portion inside thereof. Therefore, when the wafer W is adsorbed and held on the first surface S1, a gap G is formed between the wafer W and the inner portion of the first surface S1 as shown in FIG. 2.

[0043] The base member 20 is composed mainly of, for example, a metal (such as aluminum, aluminum alloy, etc.), a composite of metal and ceramics (Al - SiC), or ceramics (SiC).

[0044] A refrigerant flow path 21 is provided inside the base member 20. By flowing a refrigerant (for example, a fluorine - based inert liquid, water, etc.) through the refrigerant flow path 21, cooling of the plasma heat is performed. Specifically, when the refrigerant is flowed through the refrigerant flow path 21, the base member 20 is cooled, and the holding substrate 10 is cooled by heat transfer (heat extraction) between the base member 20 and the holding substrate 10 via the bonding material 30. As a result, the wafer W held on the first surface S1 of the holding substrate 10 is cooled. Note that the temperature of the wafer W held on the first surface S1 can be controlled by appropriately adjusting the flow rate of the refrigerant in the refrigerant flow path 21.

[0045] A base - side gas flow path 22 that constitutes a part of the flow path 60 is provided inside the base member 20. The base - side gas flow path 22 generally has a shape of a through - hole extending in the thickness direction of the base member 20, and has an inlet 22A that opens to the fourth surface S4 of the base member 20 and an outlet 22B that opens to the third surface S3. The inlet 22A serves as an inlet of the base - side gas flow path 22 and also serves as an inlet of the entire flow path 60 provided in the holding device 1.

[0046] The bonding material 30 is composed of, for example, a bonding sheet containing a silicone-based organic bonding agent, an inorganic bonding agent, or an Al-based metal adhesive. As the bonding material 30, it is preferable to have high adhesive strength to both the holding substrate 10 and the base member 20, and high pressure resistance and thermal conductivity.

[0047] A bonding-side gas flow path 31 that forms part of the flow path 60 is also formed in the bonding material 30. The bonding-side gas flow path 31 consists of holes that penetrate the layered bonding material 30 in the thickness direction.

[0048] The flow path 60 supplies a heat-conducting gas to the first surface S1 side of the holding device 1. As described above, a large number of gas flow outlets 12B, which are the outlets of the flow path 60, are provided on the first surface S1, and the heat-conducting gas is supplied to the first surface S1 side in such a manner that the heat-conducting gas is discharged from each gas flow outlet 12B. As described above, such a flow path 60 has the base-side gas flow path 22, the bonding-side gas flow path 31, and the substrate-side gas flow path 12.

[0049] A plurality of inlets 22A of the flow path 60 are provided on the fourth surface S4 of the base member 20. When the heat-conducting gas (arrow H in FIG. 2) is supplied from each inlet 22A, the heat-conducting gas sequentially passes through the base-side gas flow path 22, the bonding-side gas flow path 31, and the substrate-side gas flow path 12 connected to each inlet 22A, and is finally discharged from a plurality of gas flow outlets 12B provided on the first surface S1.

[0050] The outlet 22B of the base-side gas flow path 22 is connected to the opening on the lower side (base member 20 side) of the bonding-side gas flow path 31. Also, the opening on the upper side (holding substrate 10 side) of the bonding-side gas flow path 31 is connected to the inlet 12A of the substrate-side gas flow path 12. A plurality of inlets 12A of the substrate-side gas flow path 12 are provided on the second surface S2 of the holding substrate 10.

[0051] The second vertical flow path portion 17 including the inlet 12A of the substrate-side gas flow path 12 is connected to a plurality of horizontal flow path portions 14 on its downstream side. And a first vertical flow path portion 13 is connected to each of the horizontal flow path portions 14. That is, the substrate-side gas flow path 12 branches into a plurality of paths from the upstream side to the downstream side inside the holding substrate 10 (plate-like member 11).

[0052] The heat-conducting gas passes through the ventilation path of the porous body 70 disposed in the first vertical flow path portion 13 from the porous immediate space 15 of the horizontal flow path portion 14 and is discharged from the gas outlet 12B. At this time, the heat-conducting gas enters the porous body 70 from the pores of the bottom surface 70B facing the porous immediate space 15. In other words, the bottom surface 70B is a portion that contacts the heat-conducting gas flowing from the porous immediate space 15 and introduces the heat-conducting gas into the porous body 70. Therefore, the larger the area of the bottom surface 70B, the more the pressure loss of the heat-conducting gas in the substrate-side gas flow path 12 can be suppressed.

[0053] Next, an example of the manufacturing method of the holding device 1 of the present embodiment will be described. Here, first, with reference to FIGS. 6 and 7, the manufacturing method of the holding substrate 10 will be described. FIGS. 6 and 7 are explanatory diagrams schematically showing the manufacturing method of the holding substrate 10. The manufacturing method of this holding substrate 10 applies a sheet lamination method using a green sheet (ceramic green sheet). In FIGS. 6 and 7, the lower side (second surface S2 side) of the holding substrate 10 corresponds to the upper side of the other figures, and the upper side (first surface S1 side) of the holding substrate 10 corresponds to the lower side of the other figures.

[0054] First, as shown in FIG. 6(A), a plurality of green sheets for forming the plate-like member 11 of the holding substrate 10 are laminated to form a first laminate 80A. A conductor layer M is formed on a predetermined green sheet constituting the first laminate 80A.

[0055] The slurry for the green sheet is obtained by mixing, using a ball mill, a mixture containing, for example, alumina powder, an acrylic binder, a dispersant, a plasticizer, etc. with an organic solvent further added thereto. By forming this slurry into a sheet shape using a casting device and then drying the obtained molded article, a plurality of green sheets are obtained.

[0056] Also, the metallizing paste for forming the conductor layer M is obtained by adding and kneading conductive powder such as tungsten or molybdenum to a mixture of, for example, alumina powder, an acrylic binder, and an organic solvent. By printing this metallizing paste using, for example, a screen printing device, the conductor layer M is formed on a specific green sheet.

[0057] Next, as shown in FIG. 6(B), a hole 81 for forming the first longitudinal flow path portion 13 is formed at a predetermined position of the first laminate 80A. The hole 81 penetrates the first laminate 80A in the thickness direction. The hole 81 is formed at a predetermined position of the first laminate 80A using a known processing device (such as a router).

[0058] Next, as shown in FIG. 6(C), the hole 81 of the first laminate 80A is filled with a porous body paste P for forming the porous body 70. The porous body paste P is obtained by, for example, kneading a mixture containing alumina powder, a pore former, a binder, an organic solvent, etc. Examples of the method for filling the porous body paste P into the hole 81 include a method using an injection molding device, a method using a screen printing device, etc. Note that the first laminate 80A filled with the porous body paste P in the hole 81 is appropriately dried.

[0059] Thereafter, as shown in FIG. 7(D), the first laminate 80A and the second laminate 80B are laminated. The second laminate 80B is formed by laminating a plurality of green sheets. Note that at a predetermined location of the second laminate 80B, there are provided a hole 82 for forming the second vertical flow path portion 17, a groove 83 for forming the horizontal flow path portion 14, and a filler 84 filled in the hole 82 and the groove 83. The filler 84 is, for example, carbon paste or the like, and is a material that burns out (disappears) during firing. The laminate composed of the first laminate 80A and the second laminate 80B is, for example, composed of a laminate of 20 green sheets, and they are thermocompression bonded to each other. The outer periphery of the laminate may be appropriately cut. Then, the laminate is machined by cutting to produce a disk-shaped formed body. Thereafter, the obtained formed body is degreased and fired, and further, the formed body after degreasing and firing is fired (main firing) to obtain a fired body.

[0060] Thereafter, a mask that shields a portion corresponding to the convex outer peripheral edge portion is disposed on the surface of the fired body, and shot blasting for projecting particles such as ceramics is performed to form a convex outer peripheral edge portion on the surface of the fired body. Thereafter, the surface of this fired body is polished or the like to obtain a holding substrate 10 having a plate-like member 11 as shown in FIG. 7(E).

[0061] Note that the above-described degreasing firing and main firing are performed by disposing the laminate of the first laminate 80A and the second laminate 80B such that the first surface S1 side of the holding substrate 10 is on the upper side and the second surface S2 side is on the lower side. In such degreasing firing and main firing, the porous body paste P (unfired composition) filled in the hole 81 and the laminate of green sheets for forming the plate-like member 11 and the like are fired simultaneously.

[0062] The manufacturing method of the base member 20 is basically the same as that of the conventional product. Therefore, the detailed description thereof is omitted.

[0063] After the holding substrate 10 and the base member 20 are each fabricated, they are joined using the joining material 30. The joining of the holding substrate 10 and the base member 20 by the joining material 30 is basically the same as the joining in conventional products. Therefore, the detailed description thereof is omitted. As described above, the holding device 1 is manufactured.

[0064] Incidentally, in the lamination step of the first laminate 80A and the second laminate 80B shown in FIG. 7(D), for example, due to manufacturing tolerances or the like, the center C1 of the bottom surface 70B in plan view and the center C2 of the porous directly below space 15 in plan view may be horizontally displaced from each other, and the first laminate 80A and the second laminate 80B may be laminated in this state. FIG. 8 is a cross-sectional view showing the configuration of a holding substrate 710 according to a comparative example different from the present embodiment, and corresponds to FIG. 5 of the present embodiment. In the holding substrate 710, the area of the porous directly below space 715 in plan view is equal to the area of the bottom surface 70B in plan view. As shown in FIG. 8, when the center C1 of the bottom surface 70B in plan view and the center C2 of the porous directly below space 715 in plan view are horizontally displaced from each other, a part of the bottom surface 70B indicated by the shaded portion does not face the porous directly below space 715 and is blocked by the plate-like member 11. Therefore, the contact area between the bottom surface 70B and the heat transfer gas decreases, leading to an increase in the pressure loss of the heat transfer gas.

[0065] On the other hand, in the present embodiment, the area of the porous directly below space 15 in plan view is set to be larger than the area of the bottom surface 70B in plan view. For this reason, in the lamination step of the first laminate 80A and the second laminate 80B, even when the center C1 of the bottom surface 70B in plan view and the center C2 of the porous directly below space 15 in plan view are horizontally displaced from each other, it is easy to arrange the entire bottom surface 70B to face the porous directly below space 15 (see FIG. 5). That is, it is easy to arrange the entire bottom surface 70B so as to be in contact with the heat transfer gas. As a result, the pressure loss of the heat transfer gas can be suppressed.

[0066] <Effects of Embodiment 1> As described above, the holding device 1 of Embodiment 1 includes a first surface S1 and a second surface S2 disposed on the side opposite to the first surface S1, and includes a plate-like member 11 mainly composed of ceramics, a gas flow path (substrate-side gas flow path 12) formed inside the plate-like member 11, and a gas-permeable porous body 70 mainly composed of ceramics filled in a part of the gas flow path. The holding device 1 includes a holding substrate 10, the gas flow path includes a gas flow outlet 12B that opens to the first surface S1 side, a vertical flow path portion (first vertical flow path portion 13) that extends from the gas flow outlet 12B to the second surface S2 side, and a horizontal flow path portion 14 that is connected to the vertical flow path portion and extends parallel to the first surface S1. The porous body 70 has a bottom surface 70B on the second surface S2 side and is filled in the vertical flow path portion. The horizontal flow path portion 14 has a porous directly below space 15 disposed on the second surface S2 side with respect to the porous body 70, and the area of the porous directly below space 15 in a plan view is larger than the area of the bottom surface 70B in a plan view.

[0067] According to such a configuration, it is possible to suppress a part of the bottom surface 70B of the porous body 70 from being blocked by a part of the plate-like member 11, and it is possible to secure the contact area between the heat conduction gas introduced into the gas flow path and the porous body 70.

[0068] In Embodiment 1, it is preferable that the porous directly below space 15 has a central space 15A that overlaps the bottom surface 70B in a plan view and a peripheral space 15B disposed around the central space 15A.

[0069] According to such a configuration, by providing the peripheral space 15B, it becomes easier to further suppress a part of the bottom surface 70B of the porous body 70 from being blocked by a part of the plate-like member 11.

[0070] [Details of Embodiment 2 of the Present Disclosure] A specific example of Embodiment 2 of the present disclosure will be described with reference to FIG. 9. The holding substrate 110 included in the holding device of Embodiment 2 is configured in the same manner as the holding substrate 10 of Embodiment 1 except for the configuration of the porous directly below space 115. Hereinafter, the same members as those in Embodiment 1 will be denoted by the same reference numerals and the description thereof will be omitted.

[0071] In the holding substrate 110 of Embodiment 2, a substrate-side gas flow path 112 is provided. The substrate-side gas flow path 112 includes a first vertical flow path portion 13, a horizontal flow path portion 114, and a second vertical flow path portion 17. The porous immediate space 115 of Embodiment 2 has a central space 15A and a peripheral space 115B. The vertical dimension (thickness) of at least a part of the peripheral space 115B is larger than the thickness of the central space 15A. Note that the lower end of the central space 15A and the lower end of the peripheral space 115B may be arranged at the same position in the vertical direction. In such a configuration, the volume of the horizontal flow path portion 114 can be increased compared to Embodiment 1, making it easier to ensure the flow rate of the heat-conducting gas.

[0072] <Effects of Embodiment 2> In Embodiment 2, when the dimension in the direction (vertical direction) orthogonal to the first surface S1 is defined as the thickness, it is preferable that the thickness of the peripheral space 115B is larger than the thickness of the central space 15A.

[0073] According to such a configuration, the volume of the horizontal flow path portion 114 can be increased, making it easier to ensure the flow rate of the heat-conducting gas.

[0074] [Details of Embodiment 3 of the Present Disclosure] A specific example of Embodiment 3 of the present disclosure will be described with reference to FIG. 10. The holding substrate 210 included in the holding device of Embodiment 3 is configured in the same manner as the holding substrate 10 of Embodiment 1, except for the configuration of the porous immediate space 215. Hereinafter, the same members as those in Embodiment 1 will be denoted by the same reference numerals, and the description thereof will be omitted.

[0075] In the holding substrate 210 of Embodiment 3, a substrate-side gas flow path 212 is provided. The substrate-side gas flow path 212 includes a first vertical flow path portion 13, a horizontal flow path portion 214, and a second vertical flow path portion 17. The porous direct-under space 215 of Embodiment 3 includes a central space 15A and a peripheral space 215B. At least a part of the thickness of the peripheral space 215B is smaller than the thickness of the central space 15A. For example, the upper end of the peripheral space 215B extends in the horizontal direction, and the lower end of the peripheral space 215B may be inclined so as to approach the upper end as it goes outward (in a direction away from the central space 15A). With such a configuration, the volume of the horizontal flow path portion 214 can be reduced as compared with Embodiment 1. Therefore, for example, when the wafer W is held by the holding device and plasma processing is performed, abnormal discharge in the horizontal flow path portion 214 can be easily suppressed.

[0076] <Effects of Embodiment 3> In Embodiment 3, when the dimension in the direction orthogonal to the first surface S1 is defined as the thickness, it is preferable that the thickness of the peripheral space 215B is smaller than the thickness of the central space 15A.

[0077] According to such a configuration, by reducing the volume of the horizontal flow path portion 214, abnormal discharge in the horizontal flow path portion 214 can be easily suppressed.

[0078] [Details of Embodiment 4 of the Present Disclosure] A specific example of Embodiment 4 of the present disclosure will be described with reference to FIG. 11. The holding substrate 310 included in the holding device of Embodiment 4 is configured in the same manner as the holding substrate 10 of Embodiment 1, except for the configuration of the first vertical flow path portion 313 and the porous body 370. Hereinafter, the same members as those in Embodiment 1 will be denoted by the same reference numerals and the description thereof will be omitted.

[0079] The holding substrate 310 of Embodiment 4 is provided with a substrate-side gas flow path 312. The substrate-side gas flow path 312 includes a first vertical flow path portion 313, a horizontal flow path portion 14, and a second vertical flow path portion 17. The first vertical flow path portion 313 has a small-diameter portion 313A including a gas flow outlet 12B, a large-diameter portion 313B, and a diameter-expanding portion 313C connecting the small-diameter portion 313A and the large-diameter portion 313B. The small-diameter portion 313A is disposed at the upper end of the first vertical flow path portion 313. The large-diameter portion 313B is disposed at the lower end of the first vertical flow path portion 313. The diameter-expanding portion 313C is disposed between the small-diameter portion 313A and the large-diameter portion 313B.

[0080] When viewed from the vertical direction, the small-diameter portion 313A and the large-diameter portion 313B are circular, and the center of the small-diameter portion 313A and the center of the large-diameter portion 313B are disposed at the same position. The inner diameter of the large-diameter portion 313B is larger than the inner diameter of the small-diameter portion 313A. That is, the large-diameter portion 313B is larger in the radial direction than the small-diameter portion 313A. The inner diameter of the diameter-expanding portion 313C gradually increases downward. The diameter-expanding portion 313C extends radially outward from the small-diameter portion 313A. For example, the diameter-expanding portion 313C forms a frustum-shaped space.

[0081] The first vertical flow path portion 313 is filled with a porous body 370. The porous body 370 includes a first portion 371 disposed in the small-diameter portion 313A, a second portion 372 disposed in the large-diameter portion 313B, and a third portion 373 disposed in the diameter-expanding portion 313C. The second portion 372 and the third portion 373 constitute a wide portion 374. The wide portion 374 is disposed on the second surface S2 side (lower side) rather than the gas flow outlet 12B (small-diameter portion 313A). The wide portion 374 is larger than the gas flow outlet 12B in the radial direction. According to the present embodiment, for example, when some external force is applied to the porous body 370, the wide portion 374 and the inner wall of the first vertical flow path portion 313 are locked, so that the porous body 370 is less likely to fall off from the first vertical flow path portion 313 to the first surface S1 side.

[0082] Note that, unlike the above, the first longitudinal flow path portion 313 may be formed of the small-diameter portion 313A and the large-diameter portion 313B without forming the diameter-expanded portion 313C. In this case, the small-diameter portion 313A and the large-diameter portion 313B are directly connected. Further, the porous body 370 includes the first portion 371 and the wide portion 374 formed only of the second portion 372.

[0083] <Effect of Embodiment 4> In Embodiment 4, it is preferable that the porous body 370 is disposed on the second surface S2 side rather than the gas outlet 12B and has a wide portion 374 that is larger than the gas outlet 12B in the radial direction.

[0084] According to such a configuration, since the wide portion 374 is provided, for example, when an external force is applied to the porous body 370, it becomes difficult for the porous body 370 to drop off from the longitudinal flow path portion (the first longitudinal flow path portion 313).

[0085] <Other Embodiments> (1) The bottom surface of the porous body may not be parallel to the first surface. Further, the bottom surface may not be disposed at the same height as the opening of the first longitudinal flow path portion. For example, as shown in FIG. 12, the holding substrate 410 according to another embodiment includes a porous body 470, and the bottom surface 470B of the porous body 470 may be curved and protrude below the opening 12C (broken line portion). Further, as shown in FIG. 13, the holding substrate 510 according to another embodiment includes a porous body 570, and the bottom surface 570B of the porous body 570 may be curved and recessed above the opening 12C (broken line portion).

[0086] (2) The porous body may be filled in a part of the first longitudinal flow path portion.

[0087] (3) The upper surface of the porous body may be disposed below the first surface.

[0088] (4) The shape of the space directly below the porous body in a plan view and the shape of the bottom surface of the porous body in a plan view do not have to be substantially circular, and may be, for example, polygonal or elliptical.

Explanation of Reference Numerals

[0089] 1… Holding device 10… Holding substrate 11… Plate-shaped member 12… Gas flow path on the substrate side (an example of a gas flow path) 12B… Gas outlet 13… First vertical flow path section (an example of a vertical flow path section) 14… Horizontal flow path section 15… Porous directly below space 15A… Central space 15B… Peripheral space 70… Porous body 70B… Bottom surface S1… First surface S2… Second surface W… Wafer

Claims

1. A holding device comprising a plate-shaped member mainly composed of ceramics, including a first surface and a second surface disposed on the opposite side of the first surface, a gas flow path formed inside the plate-shaped member, and a gas-permeable porous body mainly composed of ceramics filled in a part of the gas flow path, wherein the gas flow path includes a gas flow outlet opening to the first surface side, a vertical flow path portion extending from the gas flow outlet to the second surface side, and a horizontal flow path portion connected to the vertical flow path portion and extending parallel to the first surface, the porous body has a bottom surface on the second surface side and is filled in the vertical flow path portion, the horizontal flow path portion has a porous directly-below space disposed on the second surface side with respect to the porous body, and the area of the porous directly-below space in a plan view is larger than the area of the bottom surface in the plan view. The holding device.

2. The holding device according to claim 1, wherein the porous directly-below space has a central space overlapping the bottom surface in a plan view and a peripheral space disposed around the central space.

3. The holding device according to claim 2, wherein when the dimension in the direction perpendicular to the first surface is defined as the thickness, the thickness of the peripheral space is larger than the thickness of the central space.

4. The holding device according to claim 2, wherein when the dimension in the direction perpendicular to the first surface is defined as the thickness, the thickness of the peripheral space is smaller than the thickness of the central space.

5. The holding device according to claim 1, wherein the porous body is disposed on the second surface side with respect to the gas flow outlet and has a wide portion larger in the radial direction than the gas flow outlet.

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