JP7551827B1 - Retaining device - Google Patents

Abstract

[Problem] To provide a holding device capable of preventing a gas from striking an object with force. [Solution] A holding device 100 comprising a ceramic substrate 10 having a first surface S1 for holding a wafer W, a second surface S2 located on the opposite side of the first surface S1 in a first direction, and a substrate-side gas flow passage 12 communicating with the first surface S1 and the second surface S2 and through which a gas flows, and a porous portion 70 arranged in the substrate-side gas flow passage 12, the porous portion 70 comprising a sparse region 71 and a dense region 75 having a lower porosity than the sparse region 71, the dense region 75 comprising a surface portion 76 arranged between the sparse region 71 and the first surface S1 in the first direction, and an intermediate portion 77 arranged between the sparse region 71 and the ceramic substrate 10 in a second direction perpendicular to the first direction. [Selected Figure] Figure 3

Description

This disclosure relates to a holding device.

Conventionally, the technology described in Patent Document 1 is known as a holding device. The holding device (electrostatic chuck) described in Patent Document 1 comprises a chuck body having a back surface and a chuck surface, and a plurality of conduits extending between the back surface and the chuck surface, each of which has a porous region integrated with the chuck body therein. When performing plasma processing or the like on a wafer held on the chuck surface, a heat transfer fluid such as helium gas is sent from the back surface through the porous region to the chuck surface via the conduits to increase the temperature controllability of the chuck surface.

Patent No. 4959905

However, in the configuration disclosed in Patent Document 1, if the gas passing through the duct hits the target object (wafer) with force, there is a possibility that the target object may be lifted up. On the other hand, it is desirable to improve the bonding strength between the porous portion (porous region) and the chuck body.

This disclosure is a technology that was completed based on the above circumstances, and one of its objectives is to provide a holding device that can prevent gas from hitting an object with force. Another objective is to provide a holding device that can improve the bonding strength of the porous portion.

The present disclosure relates to a holding device comprising a plate-like member having a first surface for holding an object, a second surface located on the opposite side of the first surface in a first direction, and a gas flow path through which gas flows between the first surface and the second surface, and a porous portion disposed in the gas flow path, the porous portion comprising a sparse region and a dense region having a lower porosity than the sparse region, the dense region comprising a surface portion disposed between the sparse region and the first surface in the first direction, and an intermediate portion disposed between the sparse region and the plate-like member in a second direction perpendicular to the first direction.

In the above configuration, the dense region may be in contact with the plate-like member.

In the above configuration, the holding device may include an adhesive portion that bonds the dense region and the plate-like member.

In the above configuration, when viewed in cross section in the first direction, the surface portion of the dense region may be in arch-like contact with the sparse region.

In the above configuration, the surface portion may have a flat surface that contacts the sparse region.

In the above configuration, the surface of the porous portion facing the first surface may be located closer to the second surface than the first surface.

In the above configuration, the sparse region may be disposed between the intermediate portion and the second surface in the first direction and may have a portion in contact with the gas flow path.

In the above configuration, the gas flow path may include a vertical gas flow path extending in the first direction and having the porous portion disposed therein, and a horizontal gas flow path disposed between the vertical gas flow path and the second surface and connected in a crosswise manner to the vertical gas flow path.

This disclosure makes it possible to provide a holding device that can prevent gas from hitting an object with force. It also makes it possible to provide a holding device that can improve the bonding strength of the porous portion.

FIG. 1 is an explanatory diagram showing a schematic configuration of a holding device according to a first embodiment; Schematic cross-sectional view of the internal structure of the holding device. Cross-section of the porous area FIG. 11 is a cross-sectional view showing a state in which a porous portion is pushed into a substrate-side gas flow path. 11 is a cross-sectional view of the porous portion according to the second embodiment; 11 is a cross-sectional view of the porous portion according to the third embodiment; 11 is a cross-sectional view of the porous portion according to the fourth embodiment; 13 is a cross-sectional view of the porous portion according to the fifth embodiment. FIG. 13 is a cross-sectional view showing a schematic internal structure of a holding device according to a sixth embodiment. 13 is a cross-sectional view of the porous portion according to the seventh embodiment.

<Embodiment 1>
A first embodiment of the present disclosure will be described with reference to Figures 1 to 4. The present disclosure is not limited to the following examples, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In each figure, the Z-axis direction is the vertical direction of the holding device (first direction), and the X-axis direction and the Y-axis direction are the horizontal direction of the holding device (second direction perpendicular to the first direction).

As shown in Figures 1 and 2, the holding device 100 is an electrostatic chuck that attracts and holds an object (e.g., a semiconductor wafer W) by electrostatic attraction while heating the object to a predetermined processing temperature (e.g., 50°C to 400°C). The electrostatic chuck is used as a table on which the wafer W is placed, for example, in a process of etching using plasma in a reduced pressure chamber.

The holding device 100 comprises a disk-shaped ceramic substrate (plate-shaped member) 10 and a disk-shaped base member 20 disposed below the ceramic substrate 10. The diameter of the base member 20 is larger than that of the ceramic substrate 10. For example, if the ceramic substrate 10 is disk-shaped with a diameter of 300 mm and a thickness of 3 mm, the base member 20 can be disk-shaped with a diameter of 340 mm and a thickness of 20 mm. The ceramic substrate 10 and the base member 20 are joined by a joining material 30.

The ceramic substrate 10 has a substantially circular first surface S1 that constitutes a part of the upper surface of the holding device 100 and is an adsorption surface that adsorbs and holds the wafer W, and a substantially circular second surface S2 that is located on the opposite side of the first surface S1 in the vertical direction and faces the base member 20. The base member 20 has a substantially circular third surface S3 that faces the second surface S2, and a substantially circular fourth surface S4 that is located on the opposite side of the third surface S3 in the vertical direction. The bonding material 30 is sandwiched between the second surface S2 of the ceramic substrate 10 and the third surface S3 of the base member 20 and is spread out in a layer.

The ceramic substrate 10 is an insulating substrate, and is made of a ceramic material containing, for example, alumina (Al ₂ O ₃ ) as a main component. Note that the main component refers to the component that is contained in the largest proportion (weight proportion) of the entire material.

The ceramic substrate 10 also has a plurality of substrate-side gas flow paths (gas flow paths) 12, which are through holes extending in the vertical direction and communicating with the first surface S1 and the second surface S2, and through which an inert gas (e.g., helium gas, which is a heat transfer fluid) flows. The substrate-side gas flow paths 12 constitute a part of a flow path 60 for flowing gas. The substrate-side gas flow paths 12 are formed inside the ceramic substrate 10. The substrate-side gas flow paths 12 have an inlet 12A that opens on the second surface S2 of the ceramic substrate 10 and an outlet 12B that opens on the first surface S1. The outlet 12B forms the outlet for the entire flow path 60. When an inert gas is supplied from the inlet 12A, the inert gas passes through the substrate-side gas flow paths 12 and is discharged to the outside from the outlet 12B.

The outer peripheral edge 10B of the first surface S1 of the ceramic substrate 10 is formed in a circular ring shape and protrudes slightly upward compared to the inner portion 10A. 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 10A of the first surface S1, as shown in FIG. 2. The outlets 12B of the substrate-side gas flow path 12 are provided in multiple locations on the first surface S1 (inner portion 10A).

The ceramic substrate 10 also includes a chuck electrode 40 and a heater electrode (not shown). The chuck electrode 40 is formed in a layer (planar shape) from a conductive material (e.g., tungsten, molybdenum, platinum, etc.). The chuck electrode 40 is disposed on the first surface S1 side inside the ceramic substrate 10. When a high DC voltage is applied to the chuck electrode 40 from a power source (not shown), an electrostatic force is generated, and the wafer W is attracted and fixed to the first surface S1 of the ceramic substrate 10 by this electrostatic force. The chuck electrode 40 is electrically connected to a well-known power supply terminal (not shown).

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. A coolant (e.g., a fluorine-based inert liquid, water, etc.) is caused to flow through the coolant flow path 21 to cool the plasma heat. When the coolant flows through the coolant flow path 21, the base member 20 is cooled, and the ceramic substrate 10 is cooled by heat transfer (heat transfer) between the base member 20 and the ceramic substrate 10 via the bonding material 30. As a result, the wafer W held on the first surface S1 of the ceramic 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.

The base member 20 is provided with a plurality of base-side gas flow paths 22, which are through holes extending in the vertical direction and communicating with the third surface S3 and the fourth surface S4, through which gas flows. The base-side gas flow paths 22 form part of the flow path 60. The base-side gas flow path 22 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 for the entire flow path 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. The bonding material 30 is preferably one that has high adhesive strength to both the ceramic substrate 10 and the base member 20, as well as high heat resistance and thermal conductivity. The bonding material 30 also has a bonding side gas flow path 31 that constitutes part of the flow path 60. The bonding side gas flow path 31 consists of a hole that penetrates the layered bonding material 30 in the thickness direction.

The flow path 60 supplies an inert gas to the first surface S1 side of the holding device 100. As described above, the flow path 60 includes the base side gas flow path 22, the joining side gas flow path 31, and the substrate side gas flow path 12. When an inert gas is supplied from each inlet 22A of the flow path 60, the inert gas passes through the base side gas flow path 22, the joining side gas flow path 31, and the substrate side gas flow path 12 in sequence, and is finally discharged from a plurality of outlets 12B provided on the first surface S1. The outlet 22B of the base side gas flow path 22 is connected to an opening on the lower side (base member 20 side) of the joining side gas flow path 31. In addition, the opening on the upper side (ceramic substrate 10 side) of the joining side gas flow path 31 is connected to the inlet 12A of the substrate side gas flow path 12.

As shown in Fig. 3, the holding device 100 includes a porous portion 70 disposed in a cylindrical internal space formed by the substrate-side gas flow path 12. The porous portion 70 is a gas _- permeable member mainly composed of insulating ceramics. In this embodiment, the porous portion 70 is mainly composed of alumina ( _Al2O3 ). In this embodiment, the ceramic of the porous portion 70 and the ceramic of the ceramic substrate 10 are made of the same type of ceramic. The porous portion 70 has an overall cylindrical shape.

The porous portion 70 has a plurality of voids inside, forming a mesh-like ventilation path for passing the inert gas. The shape, dimensions, and arrangement of the voids in the porous portion 70 are not particularly limited, and voids of various sizes and shapes may be randomly arranged. The proportion of the voids in the porous portion 70 is called the porosity. This porosity can be calculated, for example, by analyzing an electron microscope image of the cross section of the porous portion 70 and based on the area of the voids per unit area.

The porous section 70 includes a sparse region 71 and a dense region 75 having a lower porosity than the sparse region 71. The porosity of the sparse region 71 may be 65% to 90%, or 70% to 85%. The porosity of the dense region 75 may be 60% to 80%, or 65% to 75%, or 68% to 73%. The porosity of the dense region 75 may be 0.67 to 0.92 times, or 0.76 to 0.87 times, the porosity of the sparse region 71.

The sparse region 71 is disposed inside the dense region 75 and has a cylindrical shape with the height direction being the vertical direction. The sparse region 71 does not contact the substrate-side gas flow path 12 of the ceramic substrate 10. The lower surface 71C of the sparse region 71 is circular and flat, and is flush with the second surface S2. The dense region 75 has a gate shape in a vertical cross section (cross section in the first direction) and has a shape that covers the upper surface 71A and the side surface 71B of the sparse region 71 (a shape that contacts the upper surfaces 71A and 71B). The side surface 75B of the dense region 75 contacts the substrate-side gas flow path 12 and is integrated with each other by solid-phase bonding. In this embodiment, the side surface 75B of the dense region 75 is fixed to the substrate-side gas flow path 12 without using an adhesive (e.g., a silicone-based adhesive).

The dense region 75 includes a surface portion 76 disposed between the sparse region 71 and the first surface S1 in the vertical direction, and an intermediate portion 77 disposed between the sparse region 71 and the substrate-side gas flow path 12 of the ceramic substrate 10 in the horizontal direction. The surface portion 76 is cylindrical with its height in the vertical direction. The upper surface 76A of the surface portion 76 is circular and flat (see FIG. 1 ) and is flush with the first surface S1. The upper surface 76A of the surface portion 76 is in contact with the outlet 12B of the substrate-side gas flow path 12. The lower surface 76C of the surface portion 76 is in contact with the upper surface 71A of the sparse region 71, and is circular and flat.

The intermediate portion 77 has a cylindrical shape with its height direction being the up-down direction. The inner surface 77A of the intermediate portion 77 contacts the side surface 71B of the sparse region 71, and they are integrated with each other by solid-state welding. The lower surface 77C of the intermediate portion 77 is annular and flat, and is flush with the second surface S2 and the lower surface 71C of the sparse region 71. The lower surface 77C of the intermediate portion 77 contacts the inlet 12A of the substrate-side gas flow path 12.

The vertical length of the surface portion 76 is shorter than the vertical length of the sparse region 71. This allows gas entering the porous portion 70 from the inlet 12A to easily flow through the sparse region 71 and the surface portion 76 toward the outlet 12B. The horizontal thickness of the intermediate portion 77 is thinner than the horizontal thickness of the sparse region 71. This makes it difficult to impede the flow of gas through the porous portion 70, and allows for a structure that can improve the bonding strength between the intermediate portion 77 and the substrate-side gas flow path 12.

The manufacturing method of the holding device 100 having the porous portion 70 of this embodiment is not particularly limited, but may include, for example, a process of forming a substrate-side gas flow path 12 in a ceramic substrate 10, and a process of pushing a porous body (porous portion) 70E having a sparse region 71E and a dense region 75E having a lower porosity than the sparse region 71E into the substrate-side gas flow path 12 from the inlet 12A side, as shown in FIG. 4 (A). In the process of pushing the porous body 70E into the substrate-side gas flow path 12, the porous body 70E is pushed so that the dense region 75E contacts the inlet 12A before the sparse region 71E. As the porous body 70E to be pushed into the substrate-side gas flow path 12, a body having a lower surface 75E1 that contacts the sparse region 71E of the dense region 75E has a downward arch shape (a downward convex shape) in a cross-sectional view in the vertical direction is used. In addition, the porous body 70E to be pressed into the substrate-side gas flow path 12 has a diameter (length in the Y-axis direction) larger than the diameter of the substrate-side gas flow path 12.

Next, the effects of this embodiment will be described. In this embodiment, a holding device 100 is shown that includes a ceramic substrate 10 having a first surface S1 for holding a wafer W, a second surface S2 located on the opposite side of the first surface S1 in the vertical direction, and a substrate-side gas flow path 12 through which gas flows between the first surface S1 and the second surface S2, and a porous portion 70 arranged in the substrate-side gas flow path 12, the porous portion 70 including a sparse region 71 and a dense region 75 having a lower porosity than the sparse region 71, and the dense region 75 including a surface portion 76 arranged between the sparse region 71 and the first surface S1 in the vertical direction, and an intermediate portion 77 arranged between the sparse region 71 and the ceramic substrate 10 in the horizontal direction perpendicular to the vertical direction.

According to such a holding device 100, since the surface portion 76, which is a part of the dense region 75, is arranged between the sparse region 71 and the first surface S1, even if the gas passes through the substrate-side gas flow passage 12 and quickly fills the sparse region 71, the gas passes through the surface portion 76, which has a lower porosity than the sparse region 71, toward the first surface S1, and thus the gas can be prevented from striking the wafer W with force. This makes it possible to prevent the wafer W from being lifted up due to the gas striking with force while ensuring a sufficient flow rate of the gas flowing through the substrate-side gas flow passage 12. In addition, the strength of the porous portion 70 can be improved in the portion (surface portion 76) on the first surface S1 side. Furthermore, since the intermediate portion 77, which is a part of the dense region 75, is arranged between the sparse region 71 and the ceramic substrate 10, the intermediate portion 77 can increase the bonding area between the porous portion 70 and the ceramic substrate 10, thereby improving the bonding strength of the porous portion 70.

The dense region 75 is in contact with the ceramic substrate 10.

Such a holding device 100 can further improve the bonding strength between the porous portion 70 and the ceramic substrate 10.

<Embodiment 2>
Next, a second embodiment of the present disclosure will be described with reference to Fig. 5. In this embodiment, the same components as those in the above embodiment are designated by the same reference numerals, and redundant descriptions of the structure, operation, and effects will be omitted.

The porous portion 270 includes a sparse region 271 and a dense region 275 that has a lower porosity than the sparse region 271. The sparse region 271 is disposed inside the dense region 275. The sparse region 271 includes a cylindrical portion 272 having a height direction in the vertical direction, and a hemispherical portion 273 disposed above the cylindrical portion and having a hemispherical shape (upwardly bulging shape) with the same diameter (length in the Y-axis direction) as the cylindrical portion. The upper surface 273A of the hemispherical portion 273 is a curved surface that bulges upward, and is arch-shaped (upwardly convex) when viewed in cross section in the vertical direction.

The dense region 275 includes a surface portion 276 disposed on the outer side (surface side) of the hemispherical portion 273, and a cylindrical intermediate portion 277 disposed between the cylindrical portion 272 and the substrate-side gas flow path 12 of the ceramic substrate 10 in the horizontal direction. The surface portion 276 contacts the hemispherical portion 273 of the sparse region 271 in an arch-like manner in a vertical cross-sectional view. Specifically, the lower surface 276C of the surface portion 276 is a surface that contacts the upper surface 273A of the hemispherical portion 273, and forms a curved surface that bulges upward, and is arch-shaped (convex upward) in a vertical cross-sectional view. The surface portion 276 is shaped so that its length in the vertical direction increases from the central portion in the horizontal direction toward the outside. The surface portion 276 includes an inner portion 278 and an outer portion 279 disposed on the outer side of the inner portion 278 in the horizontal direction. The outer portion 279 is longer in the vertical direction than the inner portion 278.

The manufacturing method of the holding device 200 having the porous portion 270 of this embodiment is not particularly limited, but may include, for example, a process of forming a substrate-side gas flow path 12 in the ceramic substrate 10, and a process of pushing a porous body (porous portion) 270E having a sparse region 271E and a dense region 275E having a lower porosity than the sparse region 271E into the substrate-side gas flow path 12 from the inlet 12A side, as shown in FIG. 4(B). The porous body 270E to be pushed into the substrate-side gas flow path 12 has a lower surface 275E1 in the dense region 275E that contacts the sparse region 271E that is flat in the horizontal direction and has a linear shape when viewed in cross section in the vertical direction.

<Embodiment 3>
Next, a third embodiment of the present disclosure will be described with reference to Fig. 6. In this embodiment, the same components as those in the above embodiment are designated by the same reference numerals, and redundant descriptions of the structure, operation, and effects will be omitted.

The porous portion 370 includes a sparse region 371 and a dense region 375 that has a lower porosity than the sparse region 371. The sparse region 371 includes a first cylindrical portion 372 that is cylindrical with its height direction in the vertical direction, a second cylindrical portion 374 that is cylindrical with its height direction in the vertical direction and is disposed below the first cylindrical portion 372 and has a larger diameter (length in the Y-axis direction) than the first cylindrical portion 372, and a hemispherical portion 373 that is disposed above the first cylindrical portion 372.

The dense region 375 includes a surface portion 376 disposed on the outside (surface side) of the hemispherical portion 373, and an annular intermediate portion 377 disposed between the first cylindrical portion 372 and the substrate-side gas flow path 12 of the ceramic substrate 10 in the horizontal direction. The surface portion 376 contacts the hemispherical portion 373 in an arch shape in a vertical cross-sectional view. The lower surface 377C of the intermediate portion 377 is disposed above the second surface S2 (toward the first surface S1) in the vertical direction.

The second cylindrical portion 374 of the sparse region 371 includes a cylindrical inner portion 374A extending in the vertical direction, and a cylindrical outer portion (one portion) 374B arranged horizontally outside the inner portion 374A and extending in the vertical direction. The outer portion 374B is arranged between the middle portion 377 and the second surface S2 in the vertical direction. The outer portion 374B is in contact with the substrate-side gas flow path 12 of the ceramic substrate 10 and the lower surface 377C of the middle portion 377.

With this holding device 300, gas passing through the substrate-side gas flow path 12 from the second surface S2 can quickly flow into the porous portion 370 from the sparse region 371 including the outer portion 374B. This makes it possible to ensure a sufficient flow rate of gas passing through the substrate-side gas flow path 12 and to improve the bonding strength by the intermediate portion 377. Note that the outer portion 374B in contact with the substrate-side gas flow path 12 includes the case where the outer portion 374B is in contact with the ceramic substrate 10 and the case where an adhesive layer is interposed between the outer portion 374B and the ceramic substrate 10.

<Embodiment 4>
Next, a fourth embodiment of the present disclosure will be described with reference to Fig. 7. In this embodiment, the same components as those in the above embodiment are designated by the same reference numerals, and redundant descriptions of the structure, operation, and effects will be omitted.

In the holding device 400, the ceramic substrate 410 is provided with a plurality of substrate-side gas flow paths (gas flow paths) 412, which are through holes extending in the vertical direction and communicating with the first surface S1 and the second surface S2, and through which gas flows. The substrate-side gas flow path 412 has a cylindrical internal space extending in the vertical direction, and is provided with a first gas flow path 413 in which the porous portion 270 in the above-mentioned embodiment 2 is arranged, and a second gas flow path 414 arranged above the first gas flow path 413 and communicating with the first gas flow path 413. The first gas flow path 413 has an inlet 413A that opens to the second surface S2 of the ceramic substrate 410.

The upper surface 276A of the porous portion 270 (the surface of the porous portion 270 facing the first surface S1) is located below the first surface S1 (on the second surface S2 side). A part (intervening portion) 411 of the ceramic substrate 410 is interposed between the first surface S1 and the upper surface 276A. A second gas flow path 414 is formed through the intervening portion 411 and extends in the vertical direction.

The second gas flow path 414 includes a plurality of gas flow paths 414A and 414B. The plurality of gas flow paths 414A and 414B include an inner gas flow path 414A and an outer gas flow path 414B arranged horizontally outside the inner gas flow path 414A. Each of the plurality of gas flow paths 414A and 414B includes an outlet 414C that opens to the first surface S1 of the ceramic substrate 410. The inner gas flow path 414A is arranged above the inner portion 278 of the surface portion 276. The lower end of the inner gas flow path 414A is in contact with the inner portion 278. The outer gas flow path 414B is arranged above the outer portion 279 of the surface portion 276. The lower end of the outer gas flow path 414B is in contact with the outer portion 279.

This type of holding device 400 has a structure in which the porous portion 270 is separated from the first surface S1, so that, for example, it is possible to prevent the porous portion 270 from coming into contact with another member and causing the porous portion 270 to be scraped.

<Embodiment 5>
Next, a fifth embodiment of the present disclosure will be described with reference to Fig. 8. In this embodiment, the same components as those in the above-mentioned embodiment are designated by the same reference numerals, and redundant descriptions of the structure, operation, and effects will be omitted.

In the holding device 500, the ceramic substrate 510 is provided with a plurality of substrate-side gas flow paths (gas flow paths) 512, which are through holes extending between the first surface S1 and the second surface S2 and through which gas flows. The substrate-side gas flow paths 512, together with the base-side gas flow path 22 and the bonding-side gas flow path 31, constitute a flow path 560 for flowing an inert gas as a gas. The substrate-side gas flow paths 512 are formed inside the ceramic substrate 510.

The substrate-side gas flow passage 512 includes a vertical gas flow passage 513 extending in the vertical direction and a horizontal gas flow passage 514 extending in the horizontal direction and connected in a crosswise manner to the vertical gas flow passage 513. The vertical gas flow passage 513 includes a first vertical gas flow passage 515 and a second vertical gas flow passage 516 arranged above the first vertical gas flow passage 515. The first vertical gas flow passage 515 has an inlet 515A that opens to the second surface S2 of the ceramic substrate 510 and is connected to the upper opening of the joining side gas flow passage 31. The horizontal gas flow passage 514 is arranged between the second surface S2 and the second vertical gas flow passage 516, between the first vertical gas flow passage 515 and the second vertical gas flow passage 516. The horizontal gas flow passage 514 extends horizontally to connect the first vertical gas flow passage 515 and a plurality of second vertical gas flow passages 516 (only one second vertical gas flow passage 516 is shown in FIG. 8). The second vertical gas flow passage 516 has an outlet 516B that opens to the first surface S1. The second vertical gas flow passage 516 has a cylindrical internal space that extends in the vertical direction, and the porous portion 270 in the above-mentioned embodiment 2 is arranged in this internal space.

With this configuration, the holding device 500 is provided with a horizontal gas flow passage 514 that is connected in an intersecting manner to the second vertical gas flow passage 516 in which the porous portion 270 is arranged, so that even when there are multiple second vertical gas flow passages 516, gas can be efficiently passed through each vertical gas flow passage 516 and flowed to the porous portion 270.

In this embodiment, the holding device 500 includes an adhesive portion 580 that bonds the dense region 275 of the porous portion 270 to the ceramic substrate 510 (more specifically, the second vertical gas flow path 516 of the substrate-side gas flow path 512). The side surface 275B of the dense region 275 is bonded to the second vertical gas flow path 516 via the adhesive portion 580. For example, a silicone-based adhesive can be used as the material for the adhesive portion 580. With such a holding device 500, the bonding strength between the porous portion 270 and the ceramic substrate 510 can be further improved.

<Embodiment 6>
Next, a sixth embodiment of the present disclosure will be described with reference to Fig. 9. In this embodiment, the same components as those in the above-mentioned embodiment are designated by the same reference numerals, and redundant descriptions of the structure, operation, and effects will be omitted.

In the holding device 600, the base member 620 is provided with a plurality of base-side gas flow passages 622, which are through holes extending between the third surface S3 and the fourth surface S4 and through which gas flows. The base-side gas flow passages 622 form a part of the flow passage 660. The base-side gas flow passage 622 includes base-side vertical gas flow passages 623, 625 extending in the vertical direction and a base-side horizontal gas flow passage 624 extending in the horizontal direction and connected to the base-side vertical gas flow passages 623, 625 in a crossing manner. The base-side vertical gas flow passages 623, 625 include a first vertical gas flow passage 623 arranged below the base-side horizontal gas flow passage 624 and a plurality of second vertical gas flow passages 625 arranged above the base-side horizontal gas flow passage 624. The base-side horizontal gas flow passage 624 is arranged closer to the ceramic substrate 10 than the refrigerant flow passage 21. The first vertical gas flow passage 623 has an inlet 623A that opens to the fourth surface S4 of the base member 620. The inlet 623A forms the inlet of the entire flow passage 660 provided in the holding device 600. The second vertical gas flow passages 625 each have an outlet 625A that opens to the third surface S3. The outlets 625A are each connected to the joining side gas flow passage 31. The number of outlets 625A is greater than the number of inlets 623A. When an inert gas is supplied from the inlet 623A of the flow passage 660, the inert gas is branched by the base side gas flow passage 622, passes through the joining side gas flow passages 31 and the substrate side gas flow passages 12 in sequence, and is finally discharged from the outlets 12B provided on the first surface S1.

<Embodiment 7>
Next, a seventh embodiment of the present disclosure will be described with reference to Fig. 10. In this embodiment, the same components as those in the above embodiment are designated by the same reference numerals, and duplicated descriptions of the structure, operation, and effects will be omitted.

In the holding device 700, the porous section 770 includes a sparse region 771 and a dense region 775 with a lower porosity than the sparse region 771. The sparse region 771 includes a circular tube section 772 having a cylindrical shape with the vertical direction as the height direction, a bulging section 773 arranged above the circular tube section 772 and bulging upward in a rounded shape toward the horizontal center of the sparse region 771 as it goes upward, and a through section 774 that penetrates the circular tube section 772 and the bulging section 773 in the vertical direction at the horizontal center. The through section 774 forms a cylindrical internal space with the vertical direction as the height direction.

The dense region 775 includes a surface portion 276 disposed on the outside (surface side) of the bulge portion 773, a cylindrical intermediate portion 277 disposed between the cylindrical portion 772 and the substrate-side gas flow passage 12 of the ceramic substrate 10 in the horizontal direction, and a penetrating inner portion 778 disposed in the penetrating portion 774 at a position below the surface portion 276 (more specifically, the inner portion 278) in the vertical direction. The penetrating inner portion 778 has a cylindrical shape with the vertical direction as the height direction. The side surface 778C of the penetrating inner portion 778 facing the horizontal direction is in contact with the penetrating portion 774 and is integrated with each other by solid-state welding. The penetrating inner portion 778 is horizontally separated from the substrate-side gas flow passage 12 by the sparse region 771 and the intermediate portion 277 and is not in contact with the substrate-side gas flow passage 12. The lower surface 778A of the penetrating inner portion 778 is circular and flat. The lower surface 778A is flush with the lower surface 771A of the sparse region 771 and the lower surface 277A of the intermediate portion 277.

<Other embodiments>
The present disclosure is not limited to the embodiments described above and in the drawings, and for example, the following embodiments are also included within the technical scope of the present disclosure. Furthermore, in addition to the embodiments described below, various modifications can be made without departing from the spirit of the present disclosure.

(1) As in the first embodiment, in a porous portion disposed in a substrate-side gas flow path extending in the vertical direction, the lower surface of the porous portion (the surface facing the second surface) may be located above the second surface (on the first surface side).

(2) In addition to the above embodiments, the materials used to form each component of the holding device can be changed as appropriate.

(3) The present disclosure is not limited to the electrostatic chuck exemplified in the above embodiment, but is similarly applicable to other holding devices (e.g., heating devices, etc.) that hold an object on the surface of a ceramic substrate.

10,410,510...ceramic substrate (plate-shaped member), 12,412,512...substrate side gas flow path (gas flow path), 514...horizontal gas flow path, 516...second vertical gas flow path (vertical gas flow path), 70,270,370,770...porous portion, 71,271,371,771...sparse region, 374B...outer portion (one portion), 75,275,375,775...dense region, 76,276,376...surface portion, 77,277,377...middle portion, 100,200,300,400,500,600,700...holding device, 580...adhesive portion, S1...first surface, S2...second surface, W...wafer (object)

Claims (7)

a plate-like member having a first surface for holding an object, a second surface located on the opposite side of the first surface in a first direction, and a gas flow path communicating between the first surface and the second surface and through which a gas flows;
a porous portion disposed in the gas flow path,
The porous portion is
A sparse region;
a dense region having a lower porosity than the sparse region;
The dense region is
a surface portion disposed between the sparse region and the first surface in the first direction;
an intermediate portion disposed between the sparse region and the plate-like member in a second direction perpendicular to the first direction ;
A retention device , wherein the sparse region is disposed between the intermediate portion and the second surface in the first direction and includes a piece in contact with the gas flow path . The holding device according to claim 1, wherein the dense region is in contact with the plate-like member. The holding device according to claim 1, comprising an adhesive portion that bonds the dense region and the plate-like member. The holding device according to claim 1 or 2, wherein, in a cross-sectional view in the first direction, the surface portion of the dense region is in contact with the sparse region in an arch shape that is convex upward . The holding device according to claim 1 or 2, wherein the surface portion has a flat surface that contacts the sparse region. The holding device according to claim 1 or 2, wherein the surface of the porous portion facing the first surface is located closer to the second surface than the first surface. The gas flow path is
a vertical gas flow passage extending in the first direction and including the porous portion;
3. The retaining device according to claim 1 or 2, further comprising a transverse gas passage disposed between the vertical gas passage and the second surface and connected in a crosswise manner to the vertical gas passage.

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