JP7497492B1 - Retaining device - Google Patents

Abstract

[Problem] To provide a holding device that prevents abnormal discharge due to gas released from an electrostatic chuck during plasma processing. [Solution] In the holding device, a holding substrate 10 has a porous body 70 that releases a thermally conductive gas such as helium gas, and a horizontal passage portion 130 that is connected to a vertical passage portion 120 and extends parallel to a first surface S1 on the lower surface 70b side of the porous body 70 to reliably secure a space V for introducing a sufficient flow rate of gas into the porous body 70. The porous body 70 is filled in the vertical passage portion 120 so that a space V is formed between an end surface 70b of the porous body 70 arranged on the second surface S2 side and a bottom surface 120b1 of the vertical passage portion 120 facing the end surface 70b. The holding device includes a support portion 126 that is interposed between the bottom surface 120b1 and the end surface 70b and supports the porous body 70. [Selected Figure] FIG. 3

Description

The present invention relates to a holding device.

One example of a holding device that holds a wafer (semiconductor wafer) during semiconductor manufacturing is an electrostatic chuck (see Patent Document 1). An electrostatic chuck has a holding substrate (ceramic substrate) mainly made of insulating ceramics (e.g., 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.

In this type of electrostatic chuck, in plasma processing such as plasma etching, a thermally conductive gas such as helium gas is supplied between the holding substrate and the wafer to remove heat from the wafer. For this reason, a gas flow path is formed inside the holding substrate of the electrostatic chuck to allow the thermally conductive gas supplied from the outside to flow toward the wafer. A number of gas outlets are provided on the surface of the holding substrate at the ends of the gas flow paths, and the thermally conductive gas is supplied toward the wafer from each gas outlet.

In addition, the high frequency power applied during plasma processing can cause abnormal discharge (arcing) in the gas flow path, which can damage the wafer on the holding substrate. 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. The porous body is, for example, part of the gas flow path, and is filled inside a vertical flow path section that extends straight from the gas outlet in the thickness direction of the holding substrate, with the upper surface exposed from the gas outlet.

Patent No. 4959905

In conventional holding devices, attempts have been made to provide a space between the lower end face of the porous body and the bottom side of the vertical flow path section in order to suppress pressure loss between the gas (inert gas such as a thermally conductive gas) supplied using the gas flow path and the porous body filled in the vertical flow path section. However, when manufacturing the holding device (holding substrate), there was a risk that the porous body would shift position toward the bottom side of the vertical flow path section, causing the space on the lower side of the porous body to collapse and become impossible to secure.

The object of the present invention is to provide a holding device that reliably secures space on the underside of the porous body filled in the gas flow path to allow a sufficient flow rate of gas to be introduced into the porous body.

The means for solving the above problems are as follows.
<1> A holding device comprising a holding substrate having a plate-shaped member including a first surface for holding an object and a second surface disposed on an opposite side of the first surface, a gas flow path formed inside the plate-shaped member, and a gas-permeable porous body, wherein the gas flow path includes a gas outlet opening on the first surface side, and has a vertical flow path section extending from the gas outlet to the second surface side and filled with the porous body, and a horizontal flow path section connected to the vertical flow path section and extending parallel to the first surface, the porous body being filled in the vertical flow path section such that a space is formed between an end face of the porous body disposed on the second surface side and a bottom surface of the vertical flow path section facing the end face, and the holding device comprises a support section interposed between the bottom surface and the end face and supporting the porous body.

<2> The holding device described in <1>, in which the support portion is made of a part of the plate-like member and has a shape that protrudes from the bottom surface of the vertical flow passage portion formed inside the plate-like member toward the end surface.

<3> The holding device described in <1> or <2>, in which the space is formed between the bottom surface and the end surface so as to surround the support portion.

<4> The holding device according to any one of <1> to <3>, wherein the support portion includes an inclined surface that is inclined so as to widen from the end surface side toward the bottom surface side.

<5> The holding device according to <1> or <2>, in which there are multiple support parts and the space is formed between adjacent support parts.

<6> The holding device according to any one of <1> to <5>, wherein the support portion is made of a part of the porous body and has a convex shape from the end surface toward the bottom surface.

The present invention provides a holding device that reliably ensures space on the underside of the porous body filled in the gas flow path for introducing a sufficient flow rate of gas into the porous body.

FIG. 1 is a perspective view showing an external configuration of a holding device according to a first embodiment; FIG. 1 is a cross-sectional view showing a schematic internal structure of a holding device according to a first embodiment; Cross-sectional view of the holding substrate with a portion of the substrate-side gas flow path enlarged. AA line cross-sectional view of FIG. FIG. 1 is a schematic explanatory diagram showing a manufacturing method of a holding substrate; FIG. 1 is a schematic explanatory diagram showing a manufacturing method of a holding substrate; FIG. 11 is an enlarged cross-sectional view of a portion of a substrate-side gas flow path of a holding substrate according to a second embodiment. FIG. 11 is an enlarged cross-sectional view of a portion of a substrate-side gas flow path of a holding substrate according to a third embodiment. 11 is an explanatory diagram illustrating a manufacturing method of a holding substrate according to a third embodiment. 11 is an explanatory diagram illustrating a manufacturing method of a holding substrate according to a third embodiment. FIG. 13 is an enlarged cross-sectional view of a portion of a substrate-side gas flow path of a holding substrate according to a fourth embodiment. FIG. 13 is an enlarged cross-sectional view of a portion of a substrate-side gas flow path of a holding substrate according to a fifth embodiment. 13 is a cross-sectional view taken along line B-B of FIG.

<Embodiment 1>
A holding device 100 according to a first embodiment will be described below with reference to Fig. 1 to Fig. 6. The holding device 100 is an electrostatic chuck that attracts and holds an object (e.g., a wafer W) by electrostatic attraction. The electrostatic chuck is used as a table on which the wafer W is placed in a process of etching using plasma in a reduced pressure chamber, for example.

Fig. 1 is a perspective view showing a schematic external configuration of the holding device 100 according to the first embodiment, and Fig. 2 is a cross-sectional view showing a schematic internal structure of the holding device 100 according to the first embodiment. The holding device 100 includes a disk-shaped holding substrate (ceramic substrate) 10 and a disk-shaped base member 20 that is larger than the holding substrate 10. For example, when the holding substrate 10 is disk-shaped with a diameter of 300 mm and a thickness of 3 mm, the base member 20 is set to a disk-shaped with a diameter of 340 mm and a thickness of 20 mm. The holding substrate 10 and the base member 20 may each be provided with a positioning portion (such as a projection or recess) for aligning them with each other.

The holding substrate 10 and the base member 20 are stacked on top of each other in the vertical direction, with the holding substrate 10 placed on the top and the base member 20 placed on the bottom. The holding substrate 10 and the base member 20 are joined to each other by a joining material 30 interposed between them.

The holding substrate 10 has a first surface S1 of a substantially circular shape arranged on the upper side, and a second surface S2 of a substantially circular shape arranged 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 third surface S3 of a substantially circular shape arranged on the upper side and facing the second surface S2 of the holding substrate 10, and a fourth surface S4 of a substantially circular shape arranged on the opposite side (i.e., the lower side) of the third surface S3. The above-mentioned bonding 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 spread out in a layer.

The holding substrate 10 comprises a disk-shaped plate member 11 and a substrate-side gas flow path 12 formed inside the plate member 11. The upper surface of the plate member 11 becomes the first surface S1 of the holding substrate 10. The lower surface of the plate member 11 becomes the second surface S2 of the holding substrate 10.

The plate-shaped member 11 is a plate-shaped (disk-shaped) insulating member whose main component is ceramic. In this specification, the term "main component" means the component with the largest content. In this embodiment, the plate-shaped member 11 is made of alumina (Al ₂ O ₃ ). In other embodiments, the plate-shaped member 11 may be made of other ceramics such as aluminum nitride (AlN).

The substrate-side gas flow passage (an example of a gas flow passage) 12 constitutes a part of the flow passage 60 for flowing an inert gas (for example, helium gas, which is a thermally conductive gas) provided in the holding device 100. The substrate-side gas flow passage 12 is formed inside the plate-like member 11 of the holding substrate 10. The substrate-side gas flow passage 12 is composed of holes penetrating the holding substrate 10, including an inlet 12a opening on the second surface S2 of the holding substrate 10 and a gas outlet 12b opening on the first surface S1. When an inert gas is supplied from the inlet 12a, the inert gas passes through the substrate-side gas flow passage 12 and is finally discharged to the outside from the gas outlet 12b.

Figure 3 is a cross-sectional view of the holding substrate 10 with a portion of the substrate-side gas flow path 12 enlarged, and Figure 4 is a cross-sectional view taken along line A-A in Figure 3. Figure 3 shows the cross-sectional structure of the holding substrate 10 cut along the thickness direction. As shown in Figures 2 and 3, the substrate-side gas flow path 12 includes a first vertical flow path section 120, a horizontal flow path section 130, and a second vertical flow path section 140.

The first vertical flow passage section 120 includes a gas outlet 12b that opens on the first surface S1 side, and is a bottomed flow passage that extends from the gas outlet 12b to the second surface S2 side along the thickness direction of the plate-like member 11. The first vertical flow passage section 120 is filled with a porous body 70, which will be described later.

The horizontal flow passage section 130 is connected to the first vertical flow passage section 120 and is a flow passage extending parallel to the first surface S1. The downstream end of the horizontal flow passage section 130 is connected to the upstream end of the first vertical flow passage section 120. In the substrate side gas flow passage 12, the inlet 12a side is the upstream side, and the gas outlet 12b is the downstream side.

2, the second vertical flow passage section 140 includes an inlet 12a that opens to the second surface S2, and is a flow passage that extends from the inlet 12a to the first surface S1 along the thickness direction of the plate-like member 11. The downstream end of the second vertical flow passage section 140 is connected to the upstream end of the horizontal flow passage section 130. The inlet 12a forms the inlet of the substrate-side gas flow passage 12.

The holding substrate 10 also includes a gas-permeable porous body 70, the main component of which is ceramic, which is filled in the first vertical flow path section 120, which is part of the substrate-side gas flow path 12. Details of the porous body 70 will be described later.

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 an electrically 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-shaped 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 this 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.

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 of the first surface S1 is formed in an annular shape and protrudes slightly upward compared to the inner portion. Therefore, when the wafer W is held by suction 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.

The base member 20 is composed primarily of, for example, a metal (aluminum, aluminum alloy, etc.), a composite of metal and ceramics (Al-SiC), or ceramics (SiC).

A coolant flow path 21 is provided inside the base member 20. Plasma heat is cooled by flowing a coolant (e.g., a fluorine-based inert liquid, water, etc.) through the coolant flow path 21. When the coolant flows through the coolant flow path 21, the base member 20 is cooled, and the holding substrate 10 is cooled by heat transfer (heat transfer) 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. The temperature of the wafer W held on the first surface S1 can be controlled by appropriately adjusting the flow rate of the coolant through the coolant flow path 21.

A base-side gas flow passage 22 that constitutes part of the flow passage 60 is provided inside the base member 20. The base-side gas flow passage 22 is generally in the form 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 forms the inlet of the base-side gas flow passage 22, and also forms the inlet of the entire flow passage 60 provided in the holding device 100.

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. It is preferable that the bonding material 30 has high adhesive strength to both the holding substrate 10 and the base member 20, as well as high pressure resistance and thermal conductivity.

The joining material 30 also has a joining-side gas flow passage 31 that constitutes part of the flow passage 60. The joining-side gas flow passage 31 is made of a hole that penetrates the layered joining material 30 in the thickness direction.

The flow path 60 supplies an inert gas (such as helium gas) to the first surface S1 side of the holding device 100. As described above, the first surface S1 is provided with a large number of gas outlets 12b, which are outlets of the flow path 60, and the inert gas is supplied to the first surface S1 side by being discharged from each gas outlet 12b. As described above, such a flow path 60 includes a base side gas flow path 22, a joining side gas flow path 31, and a substrate side gas flow path (gas flow path) 12.

The inlets 22a of the flow passage 60 are provided in multiple locations on the fourth surface S4 of the base member 20. When an inert gas (arrow H in FIG. 2) is supplied from each inlet 22a, the inert gas passes through the base-side gas passage 22, the joining-side gas passage 31, and the substrate-side gas passage (gas passage) 12 connected to each inlet 22a in sequence, and is finally discharged from multiple gas outlets 12b provided on the first surface S1.

The outlet 22b of the base-side gas flow passage 22 is connected to an opening on the lower side (base member 20 side) of the joining-side gas flow passage 31. In addition, the opening on the upper side (holding substrate 10 side) of the joining-side gas flow passage 31 is connected to an inlet 12a of the substrate-side gas flow passage (gas flow passage) 12. Multiple inlets 12a of the substrate-side gas flow passage (gas flow passage) 12 are provided on the second surface S2 of the holding substrate 10.

The second vertical flow passage section 140, which includes the inlet 12a of the substrate-side gas flow passage (gas flow passage) 12, is connected to multiple horizontal flow passage sections 130 on its downstream side. Each horizontal flow passage section 130 is connected to a first vertical flow passage section 120. In other words, the substrate-side gas flow passage (gas flow passage) 12 is branched into multiple passages from the upstream side to the downstream side inside the holding substrate 10 (plate-like member 11).

Next, the porous body 70 and the substrate-side gas flow passage 12 in which the porous body 70 is filled will be described in detail.

The porous body 70 is a gas-permeable member containing a large number of pores, and is mainly composed of insulating ceramics. The porous body 70 is filled into each of the first vertical flow passages 120 in the substrate-side gas flow passage 12. The porous body 70 generally extends in the vertical direction (thickness direction of the holding substrate 10), and a mesh-like ventilation path is formed inside the porous body 70 to allow the inert gas to pass through. The ventilation path is made up of a large number of pores connected to each other within the porous body 70. The pores are formed as traces of particulate pore-forming material that is burned (disappeared) during the manufacture (firing) of the porous body 70. For example, synthetic resin beads or carbon powder are used as the pore-forming material.

As shown in FIG. 3, the first vertical flow path section 120 is generally cylindrical with a bottom that extends in the vertical direction. The first vertical flow path section 120 has a gas flow outlet 12b arranged on the first surface S1 side and a bottom 120b arranged on the second surface S2 side. The first vertical flow path section 120 also has an opening 12c with a larger diameter than the gas flow outlet 12b, located on the opposite side to the gas flow outlet 12b and above the bottom 120b (on the first surface S1 side).

Such a first vertical flow path section 120 is provided with a small diameter housing section 121 arranged at the upper end (first surface S1 side) and including a gas outlet 12b, and a large diameter housing section 122 connected to the lower end (second surface S2 side) of the small diameter housing section 121 and having an inner diameter larger than that of the small diameter housing section 121.

The small diameter accommodation portion 121 is a cylindrical hole portion including a peripheral surface 121a that extends straight along the thickness direction of the plate-like member 11 from the gas outlet 12b toward the second surface S2.

The large diameter storage section 122 is a substantially cylindrical hole including an annular ceiling surface 122a arranged to surround the lower end (the second surface S2 side) of the small diameter storage section 121, and a cylindrical peripheral surface 122b that extends straight from the outer edge of the ceiling surface 122a along the thickness direction of the plate-like member 11 to the opening 12c.

The first vertical flow path section 120 further includes a bottom-side flow path section 125 that is not filled with the porous body 70 below the large-diameter storage section 122 (the second surface S2 side). As shown in FIG. 4, the bottom-side flow path section 125 includes a bottom 120b that is circular in plan view and a substantially cylindrical circumferential surface 125a that rises from the periphery of the bottom 120b toward the large-diameter storage section 122 (the first surface S1 side). A portion of the circumferential surface 125a of the bottom-side flow path section 125 is open, and the downstream end 130b of the horizontal flow path section 130 is connected to the open portion (opening) 125b.

The bottom-side flow passage section 125 also includes a support section 126 that protrudes from the surface (bottom surface) 120b1 of the bottom section 120b toward the first surface S1. The support section 126 is made of a part of the plate-like member 11, and protrudes from the surface (bottom surface) 120b1 of the bottom section 120b of the first vertical flow passage section 120 formed inside the plate-like member 11 toward the end surface (lower end surface) 70b on the lower side (second surface S2 side) of the porous body 70. In this embodiment, as shown in FIG. 4, the support section 126 is cylindrical and is disposed approximately in the center of the bottom section 120b, which is circular in plan view.

The porous body 70 is filled into the first vertical flow passage section 120 so that a space V is formed below the porous body 70. Specifically, the porous body 70 is filled into the small diameter storage section 121 and the large diameter storage section 122 of the first vertical flow passage section 120 so that a space V is formed below the large diameter storage section 122 (on the second surface S2 side). Such a porous body 70 has a small diameter section 71 arranged on the first surface S1 side and filled into the small diameter storage section 121, and a large diameter section 72 connected to the lower end (on the second surface S2 side) of the small diameter section 71 and filled into the large diameter storage section 122. The porous body 70 and the first vertical flow passage section 120 are integrated with each other by solid-state welding.

The small diameter portion 71 is generally cylindrical and extends vertically, and is filled in the small diameter storage portion 121 of the first vertical flow path portion 120. The upper end surface 70a of the small diameter portion 71 is circular in plan view, and is exposed from the gas outlet 12b of the second surface S2. In this embodiment, the first surface S1 and the upper end surface 70a are arranged to be flush with each other. The circumferential surface of the small diameter portion 71 is in close contact with the circumferential surface 121a of the small diameter storage portion 121, and forms a ring shape that extends straight in the vertical direction.

The large diameter section 72 is a portion whose radial size is larger than the small diameter section 71 and the gas outlet 12b. The large diameter section 72 is generally cylindrical and extends in the vertical direction, and is filled in the large diameter storage section 122 of the first vertical flow path section 120. The large diameter section 72 has an annular upper surface that is in close contact with the annular ceiling surface 122a, and an annular shape that extends straight from the outer periphery of this upper surface along the thickness direction of the plate-like member 11 to the opening 12c side and is in close contact with the cylindrical peripheral surface 122b of the large diameter storage section 122.

The lower end surface 70b of the large diameter portion 72 (the end surface of the porous body 70 arranged on the second surface S2 side) is circular in plan view and is exposed to the bottom side flow passage portion 125 from the opening 12c. The lower end surface 70b is set at approximately the same height as the upper portion of the horizontal flow passage portion 130 and the opening 12c.

A support 126 is interposed between the lower end surface 70b and the surface (bottom surface) 120b1 of the bottom portion 120b, and such support 126 supports the porous body 70 from the lower end surface 70b side. The upper end surface 126a of the support 126 is in close contact with and integrated with the center portion of the lower end surface 70b of the porous body 70.

Between the surface (bottom surface) 120b1 of the bottom portion 120b and the lower end surface 70b, a space V is formed so as to surround the support portion 126. In other words, the space V forms a ring shape that surrounds the support portion 126 within the bottom side flow passage portion 125.

The inert gas supplied into the bottom-side flow passage 125 is supplied into the porous body 70 from the lower end surface 70b. The lower end surface 70b faces the entire surface (bottom surface) 120b1 of the bottom portion 120b with a space V therebetween, so that a sufficient flow rate of inert gas can be introduced into the porous body 70 from this lower end surface 70b.

As described above, the holding device 100 of this embodiment is provided with a support portion 126 that is interposed between the surface (bottom surface) 120b1 of the bottom portion 120b and the lower end surface 70b of the porous body 70 and supports the porous body 70 from the lower end surface 70b side. Therefore, in the holding device 100 of this embodiment, for example, during the manufacture of the holding device 100 (holding substrate 10), the porous body 70 is prevented from being displaced downward from the small diameter storage portion 121 and the large diameter storage portion 122 of the first vertical flow path portion 120. As a result, in the holding device 100 of this embodiment, a space V for introducing a sufficient flow rate of inert gas into the porous body 70 can be reliably secured on the lower end surface 70b side of the porous body 70.

In the present embodiment, the support 126 is made of a part of the plate-like member 11, and is formed in a convex shape from the surface (bottom surface) 120b1 of the bottom 120b in the first vertical flow path section 120 (bottom-side flow path section 125) formed inside the plate-like member 11 toward the lower end surface 70b of the porous body 70. Such a support 126 is easy to arrange at a predetermined location on the bottom 120b.

In addition, in the case of this embodiment, a space V is formed between the surface (bottom surface) 120b1 of the bottom 120b and the lower end surface 70b so as to surround the support 126, so that the inert gas supplied from the horizontal flow path 130 to the bottom side flow path 125 (space V) tends to rise along the circumferential surface of the support 126 toward the lower end surface 70b of the porous body 70 while collecting around the support 126 on the support 126 side. Therefore, in the holding device 100 of this embodiment, a sufficient flow rate of inert gas can be efficiently supplied into the porous body 70.

Next, an example of a method for manufacturing the holding device 100 of this embodiment will be described. First, a method for manufacturing the holding substrate 10 constituting the holding device 100 will be described with reference to Figs. 5 and 6. Figs. 5 and 6 are explanatory diagrams that show a schematic representation of the method for manufacturing the holding substrate 10. This method for manufacturing the holding substrate 10 is an application of a sheet lamination method that uses green sheets (ceramic green sheets). Note that in Figs. 5 and 6, the lower side (second surface S2 side) of the holding substrate 10 is shown at the top of each figure, and the upper side (first surface S1 side) of the holding substrate 10 is shown at the bottom of each figure.

First, as shown in FIG. 5(A), a plurality of green sheets for forming the plate-like member 11 of the holding substrate 10 are stacked to form a first laminate 80a. Note that a conductor layer 9 is formed on a specific green sheet constituting the first laminate 80a, and such a green sheet is stacked on other green sheets.

The slurry for green sheets is obtained, for example, by mixing a mixture containing alumina powder, acrylic binder, dispersant, plasticizer, etc., with an organic solvent added, using a ball mill. This slurry is formed into a sheet using a casting device, and the resulting formed product is then dried to obtain multiple green sheets.

The metallization paste for forming the conductor layer 9 can be obtained by, for example, adding conductive powder such as tungsten or molybdenum to a mixture of alumina powder, acrylic binder, and organic solvent, and kneading the mixture. The conductor layer 9 is formed on a specific green sheet by printing this metallization paste using, for example, a screen printing device.

Next, as shown in FIG. 5(B), holes 81 for forming the first vertical flow path section 120 are formed at predetermined locations of the first laminate 80a. The holes 81 are provided in a generally cylindrical shape penetrating the first laminate 80a in the thickness direction. The holes 81 are formed at predetermined locations of the first laminate 80a using a known processing device (router, etc.).

Next, as shown in FIG. 5(C), the holes 81 of the first laminate 80a are filled with the porous body paste 7 to form the porous body 70. The porous body paste 7 is obtained by kneading a mixture containing, for example, alumina powder, a pore former, a binder, an organic solvent, etc. Methods for filling the holes 81 with the porous body paste 7 include, for example, a method using an injection molding device and a method using a screen printing device. The first laminate 80a in which the holes 81 are filled with the porous body paste 7 is dried as appropriate.

Then, as shown in FIG. 6(D), the first laminate 80a and the second laminate 80b are laminated. The second laminate 80b is made of a plurality of green sheets laminated together. In addition, grooves 82 and holes (not shown) are provided at predetermined locations of the second laminate 80b for forming the substrate-side gas flow passage 12 (the bottom-side flow passage portion 125 of the first vertical flow passage portion 120, the horizontal flow passage portion 130, etc.). In addition, the second laminate 80b is provided with protrusions 84 for forming the support portions 126. The laminate made of the first laminate 80a and the second laminate 80b is made of, for example, 20 green sheets laminated together, which are thermally pressed together.

The outer periphery of the laminate consisting of the first laminate 80a and the second laminate 80b may be cut as appropriate. The laminate is then cut by machining to produce a disk-shaped molded body. The resulting molded body is then degreased and fired, and the degreased and fired molded body is then fired (main firing) to obtain a fired body.

A mask is then placed on the surface of the sintered body to shield the portion that corresponds to the convex outer periphery, and a convex outer periphery is formed on the surface of the sintered body by, for example, shot blasting, which projects particles of ceramics or the like. The surface of the sintered body is then polished or otherwise processed to obtain a holding substrate 10 having a plate-shaped member 11, as shown in FIG. 6(E).

The manufacturing method for the base member 20 is basically the same as that for conventional products. Therefore, a detailed explanation will be omitted.

After the holding substrate 10 and the base member 20 are produced, they are bonded together using a bonding material 30. The bonding of the holding substrate 10 and the base member 20 using the bonding material 30 is essentially the same as that used in conventional products. Therefore, a detailed description of this process will be omitted. In this manner, the holding device 100 is manufactured.

As shown in FIG. 6(D), when the first laminate 80a and the second laminate 80b are laminated, a predetermined pressure is applied to the first laminate 80a and the second laminate 80b in the thickness direction. The lower end surface of the paste 7 for porous body filled in the hole 81 of the first laminate 80a is supported by the protrusion 84 of the second laminate 80b, so that even if a predetermined pressure is applied in the thickness direction, the paste 7 for porous body is prevented from shifting toward the groove 82. Therefore, in the holding device 100 of this embodiment, a space V for introducing a sufficient flow rate of inert gas into the porous body 70 can be reliably secured on the lower end surface 70b side of the porous body 70.

<Embodiment 2>
Next, a holding substrate 10A provided in a holding device according to embodiment 2 will be described with reference to Fig. 7. Fig. 7 is an enlarged cross-sectional view of a portion of a substrate-side gas flow path 12A of a holding substrate 10A according to embodiment 2. The basic configuration of the holding substrate 10A of this embodiment is the same as that of embodiment 1. Therefore, in Fig. 7, parts corresponding to those of embodiment 1 are denoted by the same reference numerals as those of embodiment 1 with the addition of the reference numeral "A", and detailed description thereof will be omitted.

The holding substrate 10A comprises a disk-shaped plate-like member 11A and a substrate-side gas flow path 12A formed therein. The upper surface of the plate-like member 11A is the first surface SA1 of the holding substrate 10A, and the lower surface of the plate-like member 11A is the second surface SA2 of the holding substrate 10A.

As shown in FIG. 7, the substrate-side gas flow path 12A includes a first vertical flow path section 120A, a horizontal flow path section 130A, and a second horizontal flow path section (not shown). The first vertical flow path section 120A, which is a part of the substrate-side gas flow path 12A, is filled with a gas-permeable porous body 70A whose main component is ceramics.

As shown in FIG. 7, the first vertical flow path section 120A is generally cylindrical with a bottom that extends in the vertical direction. The first vertical flow path section 120A has a gas flow outlet 12Ab arranged on the first surface SA1 side and a bottom 120Ab arranged on the second surface SA2 side. The first vertical flow path section 120A also has an opening 12Ac with a larger diameter than the gas flow outlet 12Ab, located on the opposite side to the gas flow outlet 12Ab and above the bottom 120Ab (on the first surface SA1 side).

The first vertical flow path section 120A is provided with a small diameter housing section 121A arranged at the upper end (first surface SA1 side) and including a gas outlet 12Ab, and a large diameter housing section 122A connected to the lower end (second surface SA2 side) of the small diameter housing section 121A and having an inner diameter larger than that of the small diameter housing section 121A.

The first vertical flow path section 120A further includes a bottom-side flow path section 125A that is not filled with the porous body 70A below the large-diameter storage section 122A (on the second surface SA2 side). The bottom-side flow path section 125A includes a bottom section 120Ab that is circular in plan view and a substantially cylindrical circumferential surface 125Aa that rises from the periphery of the bottom section 120Ab toward the large-diameter storage section 122A (on the first surface SA1 side). A portion of the circumferential surface 125Aa of the bottom-side flow path section 125A is open, and the downstream end 130Ab of the horizontal flow path section 130A is connected to the open portion (opening) 125Ab.

The bottom-side flow passage section 125A is provided with a support section 126A that protrudes from the surface (bottom surface) 120Ab1 of the bottom section 120Ab toward the first surface SA1. The support section 126A is made of a part of the plate-like member 11A, and protrudes from the surface (bottom surface) 120Ab1 of the bottom section 120Ab of the first vertical flow passage section 120A formed inside the plate-like member 11A toward the end surface (lower end surface) 70Ab of the lower side (second surface SA2 side) of the porous body 70A.

The support column 126A of this embodiment includes an inclined surface 126Aa that is inclined so as to widen from the end surface (lower end surface) 70Ab side toward the surface (bottom surface) 120Ab1 side of the bottom portion 120Ab. The upper end 126Ab of the support column 126A is circular in plan view and is located approximately in the center of the bottom portion 120Ab. As shown in FIG. 7, the inclined surface 126Aa of the support column 126A is shaped to smoothly rise from the surface (bottom surface) 120Ab1 side of the bottom portion 120Ab toward the upper end 126Ab side. The inclined surface 126Aa is shaped to rise from the peripheral side of the bottom portion 120Ab of the bottom side flow passage portion 125A toward the upper end 126Ab located in the center.

The porous body 70A is filled into the small diameter storage section 121A and the large diameter storage section 122A of the first vertical flow path section 120A so that a space VA is formed below it. The porous body 70A has a small diameter section 71A that is filled into the small diameter storage section 121A, and a large diameter section 72A that is connected to the lower end (second surface SA2 side) of the small diameter section 71A and is filled into the large diameter storage section 122A. The porous body 70A and the first vertical flow path section 120A are integrated with each other by solid-state welding.

The upper end surface 70Aa of the small diameter portion 71A is circular in plan view and is exposed from the gas outlet 12Ab of the second surface SA2. The first surface SA1 and the upper end surface 70Aa are arranged to be flush with each other.

The lower end surface 70Ab of the large diameter portion 72A (the end surface of the porous body 70A arranged on the second surface SA2 side) is circular in plan view and is exposed to the bottom side flow passage portion 125A from the opening 12Ac. The lower end surface 70Ab is set at approximately the same height as the upper part of the horizontal flow passage portion 130A and the opening 12Ac.

A support 126A is interposed between the lower end surface 70Ab and the surface (bottom surface) 120Ab1 of the bottom portion 120Ab, and such support 126A supports the porous body 70A from the lower end surface 70Ab side. The upper end 126Ab of the support 126A is in intimate contact with and integrated with the center portion of the lower end surface 70Ab of the porous body 70A.

Between the surface (bottom surface) 120Ab1 of the bottom portion 120Ab and the lower end surface 70Ab, a space VA is formed so as to surround the periphery of the support portion 126A. In other words, the space VA forms a ring shape that surrounds the periphery of the support portion 126A within the bottom side flow passage portion 125A.

The inert gas supplied into the bottom-side flow passage 125A is supplied into the porous body 70A from the lower end surface 70Ab. The lower end surface 70Ab faces the surface (bottom surface) 120Ab1 of the bottom portion 120Ab entirely, with a space VA between them, so that a sufficient flow rate of the inert gas can be introduced into the porous body 70A from this lower end surface 70Ab.

The holding device 100A of this embodiment is provided with a support portion 126A that is interposed between the surface (bottom surface) 120Ab1 of the bottom portion 120Ab and the lower end surface 70Ab of the porous body 70A and supports the porous body 70A from the lower end surface 70Ab side. Therefore, in the holding device of this embodiment, for example, during the manufacturing of the holding device (holding substrate 10A), the porous body 70A is prevented from being displaced downward from the small diameter storage portion 121A and the large diameter storage portion 122A of the first vertical flow path portion 120A. As a result, in the holding device of this embodiment, a space VA for introducing a sufficient flow rate of inert gas into the porous body 70A can be reliably secured on the lower end surface 70Ab side of the porous body 70A.

In the present embodiment, the support 126A is made of a part of the plate member 11A, and is formed in a convex shape from the surface (bottom surface) 120Ab1 of the bottom 120Ab in the first vertical flow path section 120A (bottom side flow path section 125A) formed inside the plate member 11A toward the lower end surface 70Ab of the porous body 70A. Such a support 126A is easy to arrange at a predetermined location on the bottom 120Ab.

In addition, in the case of this embodiment, a space VA is formed between the surface (bottom surface) 120Ab1 of the bottom 120Ab and the lower end surface 70Ab so as to surround the support 126A, so that the inert gas supplied from the horizontal flow path 130A to the bottom side flow path 125A (space VA) tends to rise toward the lower end surface 70Ab of the porous body 70A along the circumferential surface of the support 126A while collecting around the support 126A. In particular, in the case of this embodiment, the support 126 includes an inclined surface 126Aa that smoothly rises from the surface (bottom surface) 120Ab1 side of the bottom 120Ab toward the upper end 126Ab side, so that the inert gas tends to collect on the upper end 126Ab side of the support 126A, and a sufficient flow rate of inert gas can be efficiently supplied into the porous body 70A.

<Embodiment 3>
Next, a holding substrate 10B provided in a holding device according to embodiment 3 will be described with reference to Fig. 8. Fig. 8 is an enlarged cross-sectional view of a portion of a substrate-side gas flow path 12B of a holding substrate 10B according to embodiment 3. The basic configuration of the holding substrate 10B of this embodiment is the same as that of embodiment 1. Therefore, in Fig. 8, parts corresponding to those of embodiment 1 are denoted by the same reference numerals as those of embodiment 1 with the addition of the reference numeral "B", and detailed description thereof will be omitted.

The holding substrate 10B comprises a disk-shaped plate-like member 11B and a substrate-side gas flow path 12B formed therein. The upper surface of the plate-like member 11B becomes the first surface SB1 of the holding substrate 10B, and the lower surface of the plate-like member 11B becomes the second surface SB2 of the holding substrate 10B.

As shown in FIG. 8, the substrate-side gas flow path 12B includes a first vertical flow path section 120B, a horizontal flow path section 130B, and a second horizontal flow path section (not shown). The first vertical flow path section 120B, which is a part of the substrate-side gas flow path 12B, is filled with a gas-permeable porous body 70B whose main component is ceramics.

As shown in FIG. 8, the first vertical flow path section 120B is generally cylindrical and extends in the vertical direction with a bottom. The first vertical flow path section 120B has a gas flow outlet 12Bb arranged on the first surface SB1 side and a bottom 120Bb arranged on the second surface SB2 side. The first vertical flow path section 120B also has an opening 12Bc with a larger diameter than the gas flow outlet 12Bb, located on the opposite side to the gas flow outlet 12Bb and above the bottom 120Bb (on the first surface SB1 side).

The first vertical flow passage section 120B is provided with a small diameter accommodation section 121B arranged at the upper end (first surface SB1 side) and including a gas flow outlet 12Bb, and a large diameter accommodation section 122B connected to the lower end (second surface SB2 side) of the small diameter accommodation section 121B and having an inner diameter larger than that of the small diameter accommodation section 121B.

The first vertical flow passage section 120B further includes a bottom-side flow passage section 125B that is not filled with the porous body 70B below the large-diameter storage section 122B (on the second surface SB2 side). The bottom-side flow passage section 125B includes a bottom section 120Bb that is circular in plan view, and a substantially cylindrical circumferential surface 125Ba that rises from the periphery of the bottom section 120Bb toward the large-diameter storage section 122B (on the first surface SB1 side). A portion of the circumferential surface 125Ba of the bottom-side flow passage section 125B is open, and the downstream end 130Bb of the horizontal flow passage section 130B is connected to the open portion (opening) 125Bb.

The porous body 70B is filled into the small diameter storage section 121B and the large diameter storage section 122B of the first vertical flow passage section 120B so that a space VB is formed below it. The porous body 70B has a small diameter section 71B that is filled into the small diameter storage section 121B, and a large diameter section 72B that is connected to the lower end (second surface SB2 side) of the small diameter section 71B and is filled into the large diameter storage section 122B.

The porous body 70B further includes a support portion 126B. The support portion 70B is made of a part of the porous body 70B, and is formed in a convex shape from the lower end surface 70Bb of the large diameter portion 72B of the porous body 70B toward the surface (bottom surface) 120Bb1 of the bottom portion 120Bb. The support portion 126B is circular in plan view and is disposed approximately in the center of the lower end surface 79Bb. The support portion 126B is integrally provided with the large diameter portion 72B. The porous body 70B and the first vertical flow path portion 120B are integrated with each other by solid-state welding.

The upper end surface 70Ba of the small diameter portion 71B has a circular shape in a plan view and is exposed from the gas flow outlet 12Bb of the second surface SB2. The first surface SB1 and the upper end surface 70Ba are arranged to be flush with each other.

The lower end surface 70Bb of the large diameter portion 72B is annular in plan view, surrounding the support portion 126B, and is exposed to the bottom side flow passage portion 125B from the opening 12Bc. The lower end surface 70Bb is set at approximately the same height as the upper portion of the horizontal flow passage portion 130B and the opening 12Bc.

The support column 126B is interposed between the lower end surface 70Bb and the surface (bottom surface) 120Bb1 of the bottom portion 120Bb, and such support column 126B supports the porous body 70B from the lower end surface 70Bb side of the large diameter portion 72B. The lower end 126Ba of the support column 126B is in intimate contact with and integrated into the center portion of the surface (bottom surface) 120Bb1 of the bottom portion 120Bb.

A space VB is formed between the surface (bottom surface) 120Bb1 of the bottom portion 120Bb and the lower end surface 70Bb so as to surround the periphery of the support portion 126B. In other words, the space VB forms a ring shape that surrounds the periphery of the support portion 126B within the bottom side flow passage portion 125B.

The inert gas supplied into the bottom-side flow passage 125B is supplied into the porous body 70B from the lower end surface 70Bb, and is also supplied into the porous body 70B from the peripheral surface 126Bb of the support 126B. The lower end surface 70Bb faces the surface (bottom surface) 120Bb1 of the bottom 120Bb entirely, with a space VB between them, so that a sufficient flow rate of inert gas can be introduced into the porous body 70B from this lower end surface 70Bb.

The holding device 100B of this embodiment is provided with a support portion 126B that is interposed between the surface (bottom surface) 120Bb1 of the bottom portion 120Bb and the lower end surface 70Bb of the porous body 70B, and supports the small diameter portion 71B and the large diameter portion 72B of the porous body 70B filled in the small diameter storage portion 121B and the large diameter storage portion 122B of the first vertical flow path portion 120B from the lower end surface 70Bb side. Therefore, in the holding device of this embodiment, for example, during the manufacture of the holding device (holding substrate 10B), the small diameter portion 71B and the large diameter portion 72B of the porous body 70B are prevented from being displaced downward from the small diameter storage portion 121B and the large diameter storage portion 122B of the first vertical flow path portion 120B. As a result, in the holding device of this embodiment, a space VB for introducing a sufficient flow rate of inert gas into the porous body 70B can be reliably secured on the lower end surface 70Bb side of the large diameter storage portion 122B of the porous body 70B.

In addition, in this embodiment, the support portion 126B is made of a part of the porous body 70B, and an inert gas can be introduced into the porous body 70B from the peripheral surface 126Bb of the support portion 126B. In addition, such a support portion 126B is easy to place at a predetermined location on the bottom portion 120Bb.

In addition, in the case of this embodiment, a space VB is formed between the surface (bottom surface) 120Bb1 of the bottom portion 120Bb and the lower end surface 70Bb so as to surround the support portion 126B, so that the inert gas supplied from the horizontal flow passage portion 130B to the bottom side flow passage portion 125B (space VB) tends to rise toward the lower end surface 70Bb of the large diameter portion 72B of the porous body 70B along the circumferential surface of the support portion 126B while collecting on the support portion 126B side. Therefore, a sufficient flow rate of inert gas can be efficiently supplied into the porous body 70B.

Next, an example of a method for manufacturing the holding substrate 10B of this embodiment will be described with reference to Figures 9 and 10. Figures 9 and 10 are explanatory diagrams that show a schematic representation of a method for manufacturing the holding substrate 10B according to embodiment 3. This method for manufacturing the holding substrate 10B is an application of a sheet lamination method that uses green sheets (ceramic green sheets), similar to embodiment 1 and the like. Note that in Figures 9 and 10, the lower side (second surface SB2 side) of the holding substrate 10B is shown at the top of each figure, and the upper side (first surface SB1 side) of the holding substrate 10B is shown at the bottom of each figure.

First, as shown in FIG. 9(A), a plurality of green sheets for forming the plate-like member 11B of the holding substrate 10B are stacked to form the first laminate 80Ba. A conductor layer 9B is formed on a specific green sheet constituting the first laminate 80Ba, and such a green sheet is stacked on other green sheets.

Next, as shown in FIG. 9(B), holes 81B for forming the first vertical flow path section 120B are formed at predetermined locations of the first laminate 80Ba. The holes 81B are provided in a substantially cylindrical shape penetrating the first laminate 80Ba in the thickness direction.

Next, as shown in FIG. 9(C), the holes 81B of the first laminate 80Ba are filled with the porous body paste 7B to form the porous body 70B. The first laminate 80Ba with the holes 81B filled with the porous body paste 7B is dried as appropriate.

Then, as shown in FIG. 9(D), a known processing device (such as a router) is used to cut a portion of the porous paste 7B in the hole 81B in the first laminate 80Ba and the green sheet for forming the plate-like member 11B to provide the protrusions 7Ba for forming the support 126B, the grooves 82B for forming the bottom side flow path 125B and the horizontal flow path 130B of the first vertical flow path 120B, etc.

Next, as shown in FIG. 9(E), the first laminate 80Ba and the second laminate 80Bb are laminated. The second laminate 80Bb is made of a stack of multiple green sheets. The stack of the first laminate 80Ba and the second laminate 80Bb is made of, for example, a stack of 20 green sheets, which are thermally pressed together.

The outer periphery of the laminate consisting of the first laminate 80Ba and the second laminate 80Bb is appropriately cut, and then the laminate is cut by machining to produce a disk-shaped molded body. The obtained molded body is then degreased and fired, and the molded body after degreasing and firing is further fired (main firing) to obtain a fired body.

A mask is then placed on the surface of the sintered body to mask the portion that corresponds to the convex outer periphery, and a shot blast is performed to project particles such as ceramics, thereby forming a convex outer periphery on the surface of the sintered body. The surface of the sintered body is then polished or otherwise processed to obtain a holding substrate 10B having a plate-shaped member 11B, as shown in FIG. 6(F).

As shown in FIG. 10(E), when the first laminate 80Ba and the second laminate 80Bb are laminated, a predetermined pressure is applied to the first laminate 80Ba and the second laminate 80Bb in the thickness direction. Since the convex portion 7Ba on the lower end surface of the paste for porous body 7B filled in the hole portion 81B of the first laminate 80Ba is supported by contacting the second laminate 80Bb, the paste for porous body 7B is prevented from shifting toward the groove portion 82B even if a predetermined pressure is applied in the thickness direction. Therefore, in the holding device 100B of this embodiment equipped with the holding substrate 10B, a space V for introducing a sufficient flow rate of inert gas into the porous body 70B can be reliably secured on the lower end surface 70Bb side of the porous body 70B.

<Embodiment 4>
Next, a holding substrate 10C provided in a holding device according to embodiment 4 will be described with reference to Fig. 11. Fig. 11 is an enlarged cross-sectional view of a portion of a substrate-side gas flow path 12C of a holding substrate 10C according to embodiment 4. The basic configuration of the holding substrate 10C of this embodiment is the same as that of embodiment 1, etc. Therefore, in Fig. 11, parts corresponding to those of embodiment 1 are denoted by the same reference numerals as those of embodiment 1 with the addition of the reference numeral "C", and detailed description thereof will be omitted.

The holding substrate 10C comprises a disk-shaped plate-like member 11C and a substrate-side gas flow path 12C formed therein. The upper surface of the plate-like member 11C becomes the first surface SC1 of the holding substrate 10C, and the lower surface of the plate-like member 11C becomes the second surface SC2 of the holding substrate 10C.

As shown in FIG. 11, the substrate-side gas flow path 12C includes a first vertical flow path section 120C, a horizontal flow path section 130C, and a second horizontal flow path section (not shown). The first vertical flow path section 120C, which is a part of the substrate-side gas flow path 12C, is filled with a gas-permeable porous body 70C whose main component is ceramics.

As shown in FIG. 11, the first vertical flow path section 120C is generally cylindrical and extends in the vertical direction with a bottom. The first vertical flow path section 120C has a gas flow outlet 12Cb arranged on the first surface SC1 side and a bottom 120Cb arranged on the second surface SC2 side. The first vertical flow path section 120C also has an opening 12Cc with a larger diameter than the gas flow outlet 12Cb, located on the opposite side to the gas flow outlet 12Cb and above the bottom 120Cb (on the first surface SC1 side).

The first vertical flow passage section 120C is provided with a small diameter accommodation section 121C arranged at the upper end (first surface SC1 side) and including a gas outlet 12Cb, and a large diameter accommodation section 122C connected to the lower end (second surface SC2 side) of the small diameter accommodation section 121C and having an inner diameter larger than that of the small diameter accommodation section 121C.

The first vertical flow passage section 120C further includes a bottom-side flow passage section 125C that is not filled with the porous body 70C below the large-diameter storage section 122C (on the second surface SC2 side). The bottom-side flow passage section 125C includes a bottom section 120Cb that is circular in plan view, and a substantially cylindrical circumferential surface 125Ca that rises from the periphery of the bottom section 120Cb toward the large-diameter storage section 122C (on the first surface SC1 side). A portion of the circumferential surface 125Ca of the bottom-side flow passage section 125C is open, and the downstream end 130Cb of the horizontal flow passage section 130C is connected to the open portion (opening) 125Cb.

The surface (bottom surface) 120Cb1 of the bottom 120Cb in the bottom-side flow passage section 125C is circular in plan view, and a cylindrical support section 126C is disposed in the center. The support section 126C is made of dense ceramics, and is a pre-sintered body (sintered body) separately from the porous body 70C and the plate-like member 11C. The support section 126C is sandwiched between the end face (lower end face) 70Cb of the lower side (second surface SC2 side) of the porous body 70C and the surface (bottom surface) 120Cb1 of the bottom 120Cb, and such support section 126C supports the porous body 70C from the lower end face 70Cb side. The support section 126C is disposed in the center of the circular lower end face 70Cb in plan view.

The porous body 70C is filled into the small diameter storage section 121C and the large diameter storage section 122C of the first vertical flow path section 120C so that a space VC is formed below it. The porous body 70C has a small diameter section 71C that is filled into the small diameter storage section 121C, and a large diameter section 72C that is connected to the lower end (second surface SC2 side) of the small diameter section 71C and is filled into the large diameter storage section 122C. The porous body 70C and the first vertical flow path section 120C are integrated with each other by solid-state welding.

The upper end surface 70Ca of the small diameter portion 71C has a circular shape in a plan view and is exposed from the gas outlet 12Cb of the second surface SC2. The first surface SC1 and the upper end surface 70Ca are arranged to be flush with each other.

The lower end surface 70Cb of the large diameter portion 72C (the end surface of the porous body 70C arranged on the second surface SC2 side) is circular in plan view and is exposed to the bottom side flow passage portion 125C from the opening 12Cc. The lower end surface 70Cb is set at approximately the same height as the upper part of the horizontal flow passage portion 130C and the opening 12Cc.

A space VC is formed between the surface (bottom surface) 120Cb1 of the bottom portion 120Cb and the lower end surface 70Cb so as to surround the periphery of the support portion 126C. In other words, the space VC forms a ring shape that surrounds the periphery of the support portion 126C within the bottom side flow passage portion 125C.

The inert gas supplied into the bottom-side flow passage section 125C is supplied into the porous body 70C from the lower end surface 70Cb. The lower end surface 70Cb faces the surface (bottom surface) 120Cb1 of the bottom portion 120Cb entirely, with a space VC between them, so that a sufficient flow rate of the inert gas can be introduced into the porous body 70C from this lower end surface 70Cb.

The holding substrate 10C of the holding device of this embodiment is provided with a support portion 126C that is interposed between the surface (bottom surface) 120Cb1 of the bottom portion 120Cb and the lower end surface 70Cb of the porous body 70C and supports the porous body 70C from the lower end surface 70Cb side. Therefore, for example, when manufacturing the holding device (holding substrate 10C), the porous body 70C is prevented from being displaced downward from the small diameter storage portion 121C and the large diameter storage portion 122C of the first vertical flow path portion 120C. As a result, in the holding device of this embodiment, a space VC for introducing a sufficient flow rate of inert gas into the porous body 70C can be reliably secured on the lower end surface 70Cb side of the porous body 70C.

In addition, in the case of this embodiment, a space VC is formed between the surface (bottom surface) 120Cb1 of the bottom portion 120Cb and the lower end surface 70Cb so as to surround the support portion 126C, so that the inert gas supplied from the horizontal flow path portion 130C to the bottom side flow path portion 125C (space VC) tends to rise toward the lower end surface 70Cb of the porous body 70C along the peripheral surface of the support portion 126C while collecting on the support portion 126C side. Therefore, a sufficient flow rate of inert gas can be efficiently supplied into the porous body 70C.

<Embodiment 5>
Next, a holding substrate 10D provided in a holding device according to embodiment 5 will be described with reference to Fig. 12 and Fig. 13. Fig. 12 is an enlarged cross-sectional view of a portion of the substrate-side gas flow path 12D of the holding substrate 10D according to embodiment 5, and Fig. 13 is a cross-sectional view taken along line B-B in Fig. 12. The basic configuration of the holding substrate 10D of this embodiment is the same as that of embodiment 1. Therefore, in Fig. 12 and Fig. 13, parts corresponding to those of embodiment 1 are denoted by the same reference numerals as those of embodiment 1 with the addition of the reference numeral "D", and detailed description thereof will be omitted.

The holding substrate 10D comprises a disk-shaped plate-like member 11D and a substrate-side gas flow path 12D formed therein. The upper surface of the plate-like member 11D is the first surface SD1 of the holding substrate 10D, and the lower surface of the plate-like member 11D is the second surface SD2 of the holding substrate 10D.

As shown in FIG. 12, the substrate-side gas flow path 12D includes a first vertical flow path section 120D, a horizontal flow path section 130D, and a second horizontal flow path section (not shown). In this embodiment, the substrate-side gas flow path 12D further includes horizontal flow path sections 131D to 133D in addition to the horizontal flow path section 130D. The porous body 70D is filled in the first vertical flow path section 120D, which is part of the plate-side gas flow path 12D.

As shown in FIG. 12, the first vertical flow path section 120D is generally cylindrical with a bottom that extends in the vertical direction. The first vertical flow path section 120D has a gas flow outlet 12Db arranged on the first surface SD1 side and a bottom 120Db arranged on the second surface SD2 side. The first vertical flow path section 120D also has an opening 12Dc with a larger diameter than the gas flow outlet 12Db, located on the opposite side to the gas flow outlet 12Db and above the bottom 120Db (on the first surface SD1 side).

The first vertical flow passage section 120D is provided with a small diameter housing section 121D arranged at the upper end (first surface SD1 side) and including a gas flow outlet 12Db, and a large diameter housing section 122D connected to the lower end (second surface SD2 side) of the small diameter housing section 121D and having an inner diameter larger than that of the small diameter housing section 121D.

The first vertical flow path section 120D further includes a bottom-side flow path section 125D below the large-diameter storage section 122D (on the second surface SA2 side). The bottom-side flow path section 125D includes a bottom section 120Db that is circular in plan view, and a substantially cylindrical circumferential surface 125Da that rises from the periphery of the bottom section 120Db toward the large-diameter storage section 122D (on the first surface SD1 side). The circumferential surface 125Da of the bottom-side flow path section 125D has four openings, and the downstream end 130Db of the horizontal flow path section 130D is connected to one of the openings (opening) 125Db. The remaining three openings 125Dc, 125Dd, and 125De are connected to the respective ends of the horizontal flow paths sections 131D, 132D, and 133D.

The porous body 70B is filled into the small diameter storage section 121D and the large diameter storage section 122D of the first vertical flow path section 120D so that a space VD is formed below it. The porous body 70D has a small diameter section 71D that is filled into the small diameter storage section 121D, and a large diameter section 72D that is connected to the lower end (second surface SD2 side) of the small diameter section 71D and is filled into the large diameter storage section 122D. The porous body 70D and the first vertical flow path section 120D are integrated with each other by solid-state welding.

The upper end surface 70Da of the small diameter portion 71D is circular in plan view and is exposed from the gas outlet 12Db of the second surface SD2. The first plane SD1 and the upper end surface 70Da are arranged to be flush with each other.

The lower end surface 70Db of the large diameter portion 72D is exposed to the bottom side flow passage portion 125D from the opening 12Dc. The lower end surface 70Db is set at approximately the same height as the upper portion of the horizontal flow passage portion 130D and the opening 12Dc.

The porous body 70D further includes a plurality of support columns 126D. In this embodiment, the porous body 70D includes four support columns 126D (126D1 to 126D4). Each support column 126D is made of a part of the porous body 70D, and is formed in a convex shape from the lower end surface 70Db of the large diameter portion 72D of the porous body 70D toward the surface (bottom surface) 120Db1 of the bottom portion 120Db. Each support column 126D is fan-shaped with a central angle of 90° in a plan view, and is arranged in four parts on the surface (bottom surface) 120Db1 of the circular bottom portion 120Db while maintaining a distance from each other. Between these four support columns 126D, a space VD is formed that perpendicularly intersects with each other, as shown in FIG. 13. In other words, the space VD is formed between adjacent support columns 126D. The porous body 70D and the first vertical flow path section 120D are integrated with each other by solid-state bonding.

Each support section 126D is interposed between the lower end surface 70Db and the surface (bottom surface) 120Db1 of the bottom section 120Db, and each support section 126D supports the porous body 70D from the lower end surface 70Db side of the large diameter section 72D. Each support section 126D is integrally formed with the large diameter section 72D.

The inert gas sent from the horizontal flow passage section 130D is supplied to the space VD in the bottom side flow passage section 125D, and then flows along the wall surface 126Da of each support section 126D and rises toward the lower end surface 70Db of the large diameter section 72D, and is introduced into the porous body 70D from the lower end surface 70Db, etc. The inert gas is also introduced into the porous body 70D from the wall surface 126Da of each support section 126D (particularly, the boundary portion between the wall surface 126Da and the surface (bottom surface) 120Db1 of the bottom section 120Db, the boundary portion between the wall surface 126Da and the lower end surface 70Db, etc.). In this way, the lower end surface 70Db of the large diameter section 72D and the wall surface 126Da of the support section 126D face the space VD, and a sufficient flow rate of inert gas can be introduced into the porous body 70D from such lower end surface 70Db, etc.

The holding substrate 10D of the holding device of this embodiment is provided with a plurality of support columns 126D that are interposed between the surface (bottom surface) 120Db1 of the bottom portion 120Db and the lower end surface 70Db of the porous body 70D and support the large diameter portion 72D of the porous body 70D from the lower end surface 70Db side. Therefore, for example, during the manufacture of the holding device (holding substrate 10D), the small diameter portion 71D and the large diameter portion 72D of the porous body 70D are prevented from being displaced downward from the small diameter storage portion 121D and the large diameter storage portion 122D of the first vertical flow path portion 120D. As a result, in the holding device of this embodiment, a space VD for introducing a sufficient flow rate of inert gas into the porous body 70D can be reliably secured on the lower end surface 70Db side of the porous body 70D.

<Other embodiments>
The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included within the technical scope of the present invention.

(1) The upper end surface of the porous body exposed from the gas outlet may be a shape other than a circle (e.g., a polygonal shape) as long as the object of the present invention is not impaired.

(2) The upper end surface of the porous body may be located below the first surface as long as this does not impair the objective of the present invention.

(3) The gas flow path for passing the inert gas does not have to be formed in the base member, but may be formed only in the holding substrate.

(4) The manufacturing method of the holding device shown in the above embodiment is one example, and other methods may be used as long as they do not impair the purpose of the present invention.

(5) In the above-mentioned embodiment 5, the inert gas is supplied to the space in the bottom side flow path section from one of the four horizontal flow path sections. However, in other embodiments, the inert gas may be supplied to the space in the bottom side flow path section from multiple horizontal flow path sections.

100...holding device, 10...holding substrate, 11...plate-like member, 12...substrate-side gas flow path (gas flow path), 12b...gas outlet, 120...first vertical flow path section (vertical flow path section), 130...horizontal flow path section, 140...second vertical flow path section, 70...porous body, 126...support section, V...space, S1...first surface, S2...second surface, W...wafer (object)

Claims (6)

A holding device including a plate-like member including a first surface for holding an object and a second surface disposed on an opposite side of the first surface, a holding substrate having a gas flow path formed inside the plate-like member, and a gas-permeable porous body,
the gas flow path includes a gas outlet opening on the first surface side, and has a vertical flow path portion extending from the gas outlet to the second surface side and filled with the porous body, and a horizontal flow path portion connected to the vertical flow path portion and extending parallel to the first surface,
the porous body is filled in the vertical flow path section such that a space is formed between an end face of the porous body arranged on the second surface side and a bottom face of the vertical flow path section opposed to the end face,
A holding device comprising a support portion interposed between the bottom surface and the end surface and supporting the porous body. The holding device according to claim 1, wherein the support portion is made of a part of the plate-like member and has a shape that protrudes from the bottom surface of the vertical flow passage portion formed inside the plate-like member toward the end surface. The holding device according to claim 1 or 2, wherein the space is formed between the bottom surface and the end surface so as to surround the support portion. The holding device according to claim 3, wherein the support portion includes an inclined surface that is inclined so as to widen from the end surface side toward the bottom surface side. The support portion is provided in a plurality of positions.
The holding device according to claim 1 or 2, wherein the space is formed between adjacent ones of the support posts. The holding device according to claim 1, wherein the support portion is made of a part of the porous body and has a convex shape extending from the end surface toward the bottom surface.

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