KR102340524B1 - Electrostatic chuck and processing apparatus - Google Patents

Abstract

[Problem] An object of the present invention is to provide an electrostatic chuck and a processing device capable of reducing arc discharge.
[Solutions] A ceramic dielectric substrate having a first main surface on which an object to be adsorbed is loaded and a second main surface opposite to the first main surface, a base plate supporting the ceramic dielectric substrate and having a gas introduction path; a first porous portion disposed on the ceramic dielectric substrate and facing the gas introduction path; and a second porous portion disposed on the base plate and facing the gas introduction path; wherein the ceramic dielectric substrate includes the first porous portion a first hole portion positioned between the main surface and the first porous portion; The porous region further has at least one first dense portion, the second porous portion having a second porous region having a plurality of pores, and a second dense region denser than the second porous region, the second porous region having at least It further has one second dense portion, wherein the first dense portion and the first hole overlap or overlap with the second dense portion when projected in a plane perpendicular to a first direction from the base plate toward the ceramic dielectric substrate. An electrostatic chuck is provided, wherein at least a portion of the first dense portion overlaps, or at least a portion of the second dense portion and at least a portion of the first dense portion contact each other.

Description

ELECTROSTATIC CHUCK AND PROCESSING APPARATUS

Aspects of the present invention relate to electrostatic chucks and processing devices.

An electrostatic chuck made of ceramic manufactured by sandwiching electrodes between ceramic dielectric substrates such as alumina and firing them applies electrostatic absorption power to built-in electrodes and attracts substrates such as silicon wafers by electrostatic force. In such an electrostatic chuck, an inert gas such as helium (He) is flowed between the front surface of the ceramic dielectric substrate and the back surface of the substrate as the object to be adsorbed to control the temperature of the substrate as the object to be adsorbed.

For example, in an apparatus which processes a substrate, such as a CVD (Chemical Vapor Deposition) apparatus, a sputtering apparatus, an ion implantation apparatus, and an etching apparatus, there exists a thing accompanying a temperature rise of a board|substrate during processing. In an electrostatic chuck used in such an apparatus, an inert gas such as He is flowed between a ceramic dielectric substrate and a substrate to be adsorbed and the inert gas is brought into contact with the substrate to suppress the temperature rise of the substrate.

In an electrostatic chuck in which substrate temperature is controlled by an inert gas such as He, a hole (gas introduction path) for introducing an inert gas such as He is formed in a ceramic dielectric substrate and a base plate supporting the ceramic dielectric substrate. Further, a through hole communicating with the gas introduction path of the base plate is formed in the ceramic dielectric substrate. Thereby, the inert gas introduced from the gas introduction path of the base plate is guided to the back surface of the substrate through the through hole of the ceramic dielectric substrate.

Here, when a substrate is processed in the apparatus, discharge (arc discharge) from the plasma in the apparatus toward the metal base plate may be generated. The gas introduction path of the base plate or the through hole of the ceramic dielectric substrate may easily become a discharge path. Accordingly, there is a technique for improving resistance to arc discharge (such as dielectric breakdown voltage) by providing a porous portion in a gas introduction path of a base plate or a through hole of a ceramic dielectric substrate. For example, Patent Document 1 discloses an electrostatic chuck in which a ceramic sintered porous body is provided in a gas introduction path, and the structure of the ceramic sintered porous body and the membrane hole are used as a gas flow path to improve insulation in the gas introduction path. In addition, Patent Document 2 discloses an electrostatic chuck in which a ceramic porous body is provided in a gas diffusion cavity and a discharge prevention member for a process gas flow path for preventing discharge is provided. In addition, Patent Document 3 discloses an electrostatic chuck that reduces arc discharge by providing a dielectric insert as a porous dielectric such as alumina. In addition, Patent Document 4 discloses a technique for forming a plurality of pores communicating with a gas supply hole by a laser processing method in an electrostatic chuck made of aluminum nitride or the like.

In such an electrostatic chuck, further reduction of arc discharge is desired.

Japanese Patent Laid-Open No. 2010-123712 Japanese Patent Laid-Open No. 2003-338492 Japanese Patent Laid-Open No. 10-50813 Japanese Patent Laid-Open No. 2009-218592

The present invention has been made based on the recognition of such a subject, and an object of the present invention is to provide an electrostatic chuck and a processing device capable of reducing arc discharge.

The first invention provides a ceramic dielectric substrate having a first main surface on which an object to be adsorbed is loaded, a second main surface opposite to the first main surface, a base plate supporting the ceramic dielectric substrate and having a gas introduction path; a first porous portion disposed on the ceramic dielectric substrate and facing the gas introduction path; and a second porous portion disposed on the base plate and facing the gas introduction path; wherein the ceramic dielectric substrate includes the first porous portion a first hole portion positioned between the main surface and the first porous portion, the first porous portion having a first porous region having a plurality of holes and a first dense region denser than the first porous region The porous region further has at least one first dense portion, the second porous portion having a second porous region having a plurality of pores, and a second dense region denser than the second porous region, wherein the second porous region is at least It further has one second dense portion, wherein the first dense portion and the first hole overlap or overlap with the second dense portion when projected in a plane perpendicular to a first direction from the base plate toward the ceramic dielectric substrate. At least a portion of the first dense portion overlaps, or at least a portion of the second dense portion and at least a portion of the first dense portion contact each other.

According to this electrostatic chuck, when the current flowing through the first porous portion flows through the second porous portion in which the second dense portion is formed, the current flows by bypassing the second dense portion. Therefore, since the distance (conduction path) through which an electric current flows can be lengthened, an electron becomes difficult to accelerate|accelerate, and by extension, generation|occurrence|production of an arc discharge can be suppressed.

In the second invention, in the first invention, when projected on a plane perpendicular to the first direction, the dimension of the first dense portion is the same as the dimension of the first hole, or the dimension of the first dense portion is It is an electrostatic chuck characterized in that it is larger than the dimension of one hole.

According to this electrostatic chuck, the current flowing through the inside of the first hole can be guided to the first dense portion. Therefore, the distance (conduction path) through which the current flows can be effectively lengthened.

According to a third aspect of the present invention, in the first or second aspect of the present invention, when projected on a plane perpendicular to the first direction, the second dense portion and the first dense region overlap, or the second dense portion and the An electrostatic chuck characterized in that the first dense region is in contact.

According to this electrostatic chuck, it is possible to suppress the current flowing through the first porous portion from flowing through the second porous portion without passing through the second dense portion. Therefore, the distance (conduction path) through which the current flows can be effectively lengthened.

A fourth invention is the invention of any one of the first to third inventions, wherein the first porous region has a plurality of first coarse portions and a first dense portion, and the first loose portions include the plurality of holes. wherein the first dense portion has a density higher than that of the first coarse portion, and a dimension in the second direction is smaller than a dimension of the first dense region in the second direction, and each of the plurality of first sparse portions extends in the first direction, the first dense portion is positioned between the plurality of first sparse portions, and the first sparse portion is formed between the plurality of holes. An electrostatic chuck having a first wall portion, wherein a minimum dimension of the first wall portion in a second direction substantially orthogonal to the first direction is smaller than a minimum value of the dimension of the first dense portion.

According to this electrostatic chuck, since the first coarse portion and the first dense portion extending in the first direction are formed in the first porous portion, the mechanical strength ( stiffness) can be improved.

A fifth invention is the invention of any one of the first to fourth inventions, wherein the dimension of the plurality of holes formed in each of the plurality of first coarse portions in the second direction is that of the first dense portion. and/or a dimension of the plurality of holes formed in each of the plurality of second coarse portions in the second direction is smaller than a dimension of the second dense portion.

According to this electrostatic chuck, since the dimensions of the plurality of holes can be made sufficiently small, resistance to arc discharge can be further improved.

A sixth invention is the invention of any one of the first to fifth inventions, wherein an aspect ratio of the plurality of holes formed in each of the plurality of first coarse portions and/or an aspect ratio of the plurality of holes formed in each of the plurality of second coarse portions is provided. An aspect ratio of the plurality of holes is 30 or more.

According to this electrostatic chuck, resistance to arc discharge can be further improved.

A seventh invention is the invention of any one of the first to sixth inventions, wherein in the second direction, the dimensions of the plurality of holes formed in each of the plurality of first coarse portions and/or the plurality of second The size of the plurality of holes formed in each of the sparse portions is 1 micrometer or more and 20 micrometers or less.

According to this electrostatic chuck, since holes extending in one direction with a dimension of 1 to 20 micrometers can be arranged, high resistance to arc discharge can be realized.

The eighth invention is the first invention according to any one of the first to seventh inventions, wherein the plurality of holes formed in the first open portion when viewed along the first direction are located in the center of the first open portion. a plurality of holes including holes, the number of holes adjacent to and surrounding the first hole among the plurality of holes is six, and/or a plurality of holes formed in the second sparse portion when viewed along the first direction the hole of the second hole includes a second hole located in the center of the second coarse portion, and the number of holes adjacent to the second hole and surrounding the second hole among the plurality of holes is six. pretend

According to this electrostatic chuck, it becomes possible to arrange a plurality of holes with high isotropy and high density in plan view. Thereby, the rigidity of a 1st porous part can be improved, ensuring resistance with respect to arc discharge and the flow volume of flowing gas.

The ninth invention is any one of the first to ninth inventions, wherein the length of the first dense portion along the first direction is smaller than the length of the first porous portion along the first direction. it is an electrostatic chuck

According to this electrostatic chuck, resistance to arc discharge can be further improved.

A tenth invention is the electrostatic chuck according to any one of the first to ninth inventions, wherein the first porous region is formed between the first dense portion and the base plate in the first direction. to be.

According to this electrostatic chuck, resistance to arc discharge can be further improved.

An eleventh invention is the invention of any one of the first to tenth inventions, wherein the length of the first dense portion along the first direction is approximately equal to the length of the first porous portion along the first direction. It is an electrostatic chuck that

According to this electrostatic chuck, resistance to arc discharge can be further improved.

According to a twelfth invention, in any one of the first to eleventh inventions, the plurality of first coarse portions are formed around the first dense portion when projected onto a plane perpendicular to the first direction. characterized.

According to this electrostatic chuck, generation of arc discharge can be effectively suppressed while ensuring gas flow.

A thirteenth invention is the invention of any one of the first to twelfth inventions, wherein the average value of the diameters of the plurality of holes formed in the second porous portion is higher than the average value of the diameters of the plurality of holes formed in the first porous portion. It is an electrostatic chuck characterized by a large size.

According to this electrostatic chuck, since the second porous portion having a large hole diameter is provided, the flow of gas can be facilitated. Moreover, since the 1st porous part with a small diameter of a hole is provided in the object side of adsorption|suction, generation|occurrence|production of an arc discharge can be suppressed more effectively.

A fourteenth invention is the electrostatic chuck according to any one of the first to thirteenth inventions, wherein at least a part of an edge of the opening of the gas introduction path on the ceramic dielectric substrate side is formed in a curved shape.

According to this electrostatic chuck, since at least a part of the edge of the opening of the gas introduction path is curved, the concentration of the electric field can be suppressed and, consequently, the arc discharge can be reduced.

A fifteenth invention is the invention of any one of the first to fourteenth inventions, wherein the ceramic dielectric substrate has a first hole portion positioned between the first main surface and the first porous portion, the ceramic dielectric substrate and the At least one of the first porous portions has a second hole located between the first hole and the first porous portion, and the dimension of the second hole in a second direction substantially orthogonal to the first direction is An electrostatic chuck characterized in that it is smaller than the dimension of the first porous part and larger than the dimension of the first hole part.

According to this electrostatic chuck, resistance to arc discharge can be improved while ensuring the flow rate of the gas flowing through the first hole by the first porous portion provided at a position opposite to the gas introduction passage. Further, since the second hole having a predetermined dimension is provided, most of the gas introduced into the first porous portion having a large dimension can be introduced into the first hole having a small dimension through the second hole portion. That is, reduction of arc discharge and smoothing of gas flow can be aimed at.

A sixteenth invention is a processing apparatus comprising the electrostatic chuck according to any one of the above and a supply unit capable of supplying a gas to a gas introduction path formed in the electrostatic chuck.

According to this processing apparatus, reduction of arc discharge can be aimed at.

According to an aspect of the present invention, an electrostatic chuck and a processing apparatus capable of reducing arc discharge are provided.

1 is a schematic cross-sectional view illustrating an electrostatic chuck according to the present embodiment.
2A to 2D are schematic diagrams illustrating an electrostatic chuck according to an embodiment.
3A and 3B are schematic diagrams illustrating a porous portion of an electrostatic chuck according to an embodiment.
4 is a schematic plan view illustrating a porous portion of an electrostatic chuck according to an embodiment.
5 is a schematic plan view illustrating a porous portion of an electrostatic chuck according to an embodiment.
6A and 6B are schematic plan views illustrating a porous portion of an electrostatic chuck according to an embodiment.
7(a), (b) is a schematic diagram illustrating the 1st porous part 90 by another embodiment.
8 is a schematic cross-sectional view illustrating an electrostatic chuck according to an embodiment.
9A and 9B are schematic cross-sectional views illustrating an electrostatic chuck according to an embodiment.
10 is a schematic cross-sectional view illustrating a porous portion of an electrostatic chuck according to an embodiment.
11 is a schematic cross-sectional view illustrating a porous part according to another embodiment.
12(a) and 12(b) are schematic cross-sectional views illustrating a porous part according to another embodiment.
13(a) to (d) are schematic cross-sectional views illustrating a porous part according to another embodiment.
14A to 14C are schematic cross-sectional views illustrating a porous part according to another embodiment.
15(a), (b) are schematic cross-sectional views illustrating a porous part according to another embodiment.
16 is a schematic cross-sectional view illustrating an electrostatic chuck according to another embodiment.
17A and 17B are enlarged views of the region C shown in FIG. 16 .
18 is a schematic cross-sectional view illustrating a plurality of holes according to another embodiment.
19(a) and (b) are schematic cross-sectional views illustrating the shape of the opening portion of the hole.
20 is a schematic cross-sectional view illustrating an electrostatic chuck according to another embodiment.
21 is a schematic cross-sectional view illustrating an electrostatic chuck according to another embodiment.
22 is a schematic cross-sectional view illustrating an electrostatic chuck according to another embodiment.
Fig. 23 is an enlarged view of the region E shown in Fig. 22 .
Fig. 24 is an enlarged view showing another embodiment of the region E shown in Fig. 22 .
25 is a schematic diagram illustrating a processing apparatus according to the present embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring drawings. In addition, in each figure, the same code|symbol is attached|subjected to the same component, and detailed description is abbreviate|omitted suitably.

In each figure, the direction from the base plate 50 to the ceramic dielectric substrate 11 is the Z direction (corresponding to an example of the first direction), and one of the directions substantially orthogonal to the Z direction is the Y direction (the second direction). Corresponding to an example of the direction), a direction substantially orthogonal to the Z direction and the Y direction is defined as the X direction (corresponding to an example of the second direction).

(Electrostatic chuck)

1 is a schematic cross-sectional view illustrating an electrostatic chuck according to the present embodiment.

1 , the electrostatic chuck 110 according to the present embodiment includes a ceramic dielectric substrate 11 , a base plate 50 , and a porous portion 90 . In this example, the electrostatic chuck 110 further includes a porous portion 70 .

The ceramic dielectric substrate 11 is a flat substrate made of, for example, sintered ceramic. For example, the ceramic dielectric substrate 11 includes aluminum oxide (Al ₂ O ₃ ). For example, the ceramic dielectric substrate 11 is formed of high-purity aluminum oxide. The concentration of aluminum oxide in the ceramic dielectric substrate 11 is, for example, 99 atomic percent or more and 100 atomic percent or less. Plasma resistance of the ceramic dielectric substrate 11 can be improved by using high-purity aluminum oxide. The ceramic dielectric substrate 11 has a first main surface 11a on which an object W (adsorption object) is mounted, and a second main surface 11b opposite to the first main surface 11a. The object W is, for example, a semiconductor substrate such as a silicon wafer.

An electrode 12 is formed on the ceramic dielectric substrate 11 . The electrode 12 is formed between the first main surface 11a and the second main surface 11b of the ceramic dielectric substrate 11 . The electrode 12 is formed to be inserted into the ceramic dielectric substrate 11 . A power source 210 is electrically connected to the electrode 12 through a connection part 20 and a wiring 211 . By applying a voltage for adsorption to the electrode 12 by the power supply 210, an electric charge is generated on the first main surface 11a side of the electrode 12, and the object W can be adsorbed and held by the electrostatic force. .

The shape of the electrode 12 is a thin film shape along the first and second main surfaces 11a and 11b of the ceramic dielectric substrate 11 . The electrode 12 is an adsorption electrode for adsorbing and holding the object W. The electrode 12 may be of a unipolar type or a bipolar type. The electrode 12 illustrated in FIG. 1 is a bipolar type, and the electrode 12 of two poles is formed on the same surface.

A connection portion 20 extending toward the second main surface 11b of the ceramic dielectric substrate 11 is formed in the electrode 12 . The connecting portion 20 is, for example, a via (solid type) or a via hole (hollow type) that conducts with the electrode 12 . The connecting portion 20 may be a metal terminal connected by an appropriate method such as brazing.

The base plate 50 is a member that supports the ceramic dielectric substrate 11 . The ceramic dielectric substrate 11 is fixed on the base plate 50 by the bonding portion 60 illustrated in FIG. 2( a ). The junction part 60 can be made into what hardened|cured the silicone adhesive agent, for example.

The base plate 50 is made of metal, for example. The base plate 50 is divided into an upper part 50a and a lower part 50b made of, for example, aluminum, and a communication path 55 is formed between the upper part 50a and the lower part 50b. One end of the communication path 55 is connected to the input path 51 , and the other end of the communication path 55 is connected to the output path 52 . The base plate 50 may have a thermal spraying part (not shown) in the edge part by the side of the 2nd main surface 11b. A thermal spraying part is formed by thermal spraying, for example. The sprayed portion may constitute an end surface (upper surface 50U) of the base plate 50 on the side of the second main surface 11b. A thermal spraying part is formed as needed, and can be omitted.

The base plate 50 also serves to adjust the temperature of the electrostatic chuck 110 . For example, when cooling the electrostatic chuck 110 , the cooling medium flows in from the input path 51 , passes through the communication path 55 , and flows out from the output path 52 . Thereby, the heat of the base plate 50 can be absorbed by the cooling medium, and the ceramic dielectric substrate 11 mounted thereon can be cooled. Meanwhile, when the electrostatic chuck 110 is kept warm, it is also possible to put a heat insulating medium in the communication path 55 . It is also possible to embed the heating element in the ceramic dielectric substrate 11 or the base plate 50 . By adjusting the temperature of the base plate 50 or the ceramic dielectric substrate 11 , the temperature of the object W adsorbed and held by the electrostatic chuck 110 may be adjusted.

In addition, dots 13 are formed on the side of the first main surface 11a of the ceramic dielectric substrate 11 as needed, and grooves 14 are formed between the dots 13 . That is, the first main surface 11a is an uneven surface, and has a concave portion and a convex portion. The convex portion of the first main surface 11a corresponds to the dots 13 , and the concave portion of the first main surface 11a corresponds to the groove 14 . The groove 14 can be extended continuously in the XY plane, for example. Thereby, a gas such as He can be distributed to the entire first main surface 11a. A space is formed between the back surface of the object W loaded on the electrostatic chuck 110 and the first main surface 11a including the groove 14 .

The ceramic dielectric substrate 11 has a through hole 15 connected to the groove 14 . The through hole 15 is formed from the second main surface 11b to the first main surface 11a. That is, the through hole 15 extends from the second main surface 11b to the first main surface 11a in the Z direction to penetrate the ceramic dielectric substrate 11 . The through hole 15 includes, for example, a hole portion 15a, a hole portion 15b, a hole portion 15c, and a hole portion 15d (details will be described later).

By appropriately selecting the height of the dot 13, the depth of the groove 14, the area ratio of the dots 13 and the groove 14, the shape, etc., the temperature of the object W or the particles attached to the object W are desirable. state can be controlled.

A gas introduction path 53 is formed in the base plate 50 . The gas introduction path 53 is formed to pass through the base plate 50 , for example. The gas introduction path 53 may not penetrate the base plate 50 and may be formed to branch from the middle of another gas introduction path 53 to the ceramic dielectric substrate 11 side. In addition, the gas introduction passage 53 may be formed in a plurality of locations of the base plate 50 .

The gas introduction path 53 communicates with the through hole 15 . That is, the gas (such as helium (He)) flowing into the gas introduction passage 53 flows into the through hole 15 after passing through the gas introduction passage 53 .

The gas flowing into the through hole 15 flows into the space formed between the object W and the first main surface 11a including the groove 14 after passing through the through hole 15 . Thereby, the target object W can be directly cooled with gas.

The porous portion 90 can be provided, for example, between the base plate 50 and the first main surface 11a of the ceramic dielectric substrate 11 in the Z direction. The porous part 90 can be provided in the position opposite to the gas introduction path 53, for example. For example, the porous portion 90 is provided in the through hole 15 of the ceramic dielectric substrate 11 . For example, the porous portion 90 is inserted into the through hole 15 .

2A and 2B are schematic diagrams illustrating an electrostatic chuck according to an embodiment. FIG. 2( a ) illustrates the porous part 90 and the periphery of the porous part 70 . FIG.2(a) corresponds to the enlarged view of the area|region A shown in FIG. FIG. 2B is a plan view illustrating the porous portion 90 .

In addition, FIG.2(c), (d) is a schematic sectional drawing for illustrating the hole part 15c and the hole part 15d by another embodiment.

In addition, in order to avoid complication, the dot 13 (refer FIG. 1) is abbreviate|omitted in Fig.2 (a), (c), and (d), and is drawn.

In this example, the through hole 15 has a hole portion 15a and a hole portion 15b (first hole portion). One end of the hole 15a is located on the second main surface 11b of the ceramic dielectric substrate 11 .

Also, the ceramic dielectric substrate 11 may have a hole portion 15b positioned between the first main surface 11a and the porous portion 90 in the Z direction. The hole portion 15b communicates with the hole portion 15a and extends to the first main surface 11a of the ceramic dielectric substrate 11 . That is, one end of the hole 15b is located on the first main surface 11a (the bottom surface 14a of the groove 14). The hole 15b is positioned between the first main surface 11a of the ceramic dielectric substrate 11 and the first porous portion 90 . The hole 15b is a connecting hole connecting the porous portion 90 and the groove 14 . The diameter (length along the X direction) of the hole portion 15b is smaller than the diameter (length along the X direction) of the hole portion 15a. Degree of freedom in the design of the space (for example, the first main surface 11a including the groove 14) formed between the ceramic dielectric substrate 11 and the object W by forming the small-diameter hole 15b can increase For example, as shown in FIG. 2A , the width (length along the X direction) of the groove 14 may be shorter than the width (length along the X direction) of the porous portion 90 . Thereby, for example, discharge in the space formed between the ceramic dielectric substrate 11 and the object W can be suppressed.

The diameter of the hole 15b is, for example, 0.05 mm (mm) or more and 0.5 mm or less. The diameter of the hole 15a is, for example, 1 mm or more and 5 mm or less. In addition, the hole 15b may communicate indirectly with the hole 15a. That is, the hole part 15c (2nd hole part) which connects the hole part 15a and the hole part 15b may be formed. As illustrated in FIG. 2A , the hole 15c may be formed in the ceramic dielectric substrate 11 . As illustrated in FIG. 2(c) , the hole 15c may be formed in the porous part 90 . As illustrated in FIG. 2D , the hole 15c may be formed in the ceramic dielectric substrate 11 and the porous portion 90 . That is, at least one of the ceramic dielectric substrate 11 and the porous portion 90 may have a hole portion 15c positioned between the hole portion 15b and the porous portion 90 . In this case, if the hole portion 15c is formed in the ceramic dielectric substrate 11, the strength around the hole portion 15c can be increased, and chipping or the like around the hole portion 15c can be increased. occurrence can be suppressed. Therefore, generation|occurrence|production of an arc discharge can be suppressed more effectively. When the hole 15c is formed in the porous portion 90 , the alignment between the hole 15c and the porous portion 90 becomes easy. Therefore, it becomes easier to achieve both reduction of arc discharge and smoothing of gas flow. Each of the hole 15a, the hole 15b, and the hole 15c is, for example, a cylindrical shape extending in the Z direction.

In this case, in the X-direction or Y-direction, the dimension of the hole 15c can be smaller than the dimension of the porous part 90 and larger than the dimension of the hole 15b. According to the electrostatic chuck 110 according to the present embodiment, resistance to arc discharge while ensuring the flow rate of the gas flowing through the hole 15b by the porous portion 90 provided at a position opposite to the gas introduction passage 53 can improve In addition, since the dimension of the hole 15c in the X direction or the Y direction is larger than the above-mentioned dimension of the hole 15b, most of the gas introduced into the large porous portion 90 is absorbed by the hole 15c. It can be introduced into the hole 15b having a small dimension through the . That is, reduction of arc discharge and smoothing of gas flow can be aimed at.

As described above, the ceramic dielectric substrate 11 has at least one groove 14 that is opened in the first main surface 11a and communicates with the through hole 15 . In addition, the dimension in the Z direction of the hole 15c can be made smaller than the dimension in the Z direction of the groove 14 . Thereby, the time for the gas to pass through the hole 15c can be shortened. That is, generation|occurrence|production of an arc discharge can be suppressed more effectively, aiming at smoothing of a gas flow. In addition, the dimension of the hole 15c can be made larger than the dimension of the groove|channel 14 in the X direction or the Y direction. In this way, it becomes easy to introduce gas into the groove 14 . Therefore, it becomes possible to cool the target object W effectively with gas.

In addition, the arithmetic mean surface roughness Ra of the surface 15c1 (ceiling surface) on the first main surface 11a side of the hole 15c is the bottom surface 14a of the groove 14 (the second main surface 11b). It is preferable to make it smaller than the arithmetic mean surface roughness Ra of the side surface). In this way, since there is no large unevenness|corrugation on the surface 15c1 of the hole part 15c, generation|occurrence|production of an arc discharge can be suppressed effectively.

Moreover, it is preferable to make the arithmetic mean surface roughness Ra of the surface 14a on the 2nd main surface 11b side of the groove|channel 14 smaller than the arithmetic mean surface roughness Ra of the 2nd main surface 11b. In this way, since there is no large unevenness|corrugation on the surface 14a of the groove|channel 14, generation|occurrence|production of an arc discharge can be suppressed effectively.

Moreover, the hole part 15d (3rd hole part) formed between the hole part 15b and the hole part 15c can be further provided. In the X-direction or Y-direction, the dimension of the hole 15d can be larger than that of the hole 15b and smaller than the hole 15c. When the hole 15d is formed, the flow of gas can be facilitated.

As described above, the bonding portion 60 may be provided between the ceramic dielectric substrate 11 and the base plate 50 . In the Z direction, the dimension of the hole portion 15c can be made smaller than the dimension of the joint portion 60 . In this way, the bonding strength between the ceramic dielectric substrate 11 and the base plate 50 can be improved. Moreover, since the dimension of the hole 15c in the Z direction is made smaller than the dimension of the junction part 60, generation|occurrence|production of an arc discharge can be suppressed more effectively, aiming at the smoothness of a gas flow.

In this example, the porous part 90 is provided in the hole part 15a. For this reason, 90 U of upper surfaces of the porous part 90 are not exposed to the 1st main surface 11a. That is, the upper surface 90U of the porous portion 90 is positioned between the first main surface 11a and the second main surface 11b. On the other hand, the lower surface 90L of the porous part 90 is exposed to the 2nd main surface 11b.

Next, the porous part 90 is demonstrated. The porous portion 90 has a plurality of coarse portions 94 and a plurality of dense portions 95 described later. In addition, although the case where the porous part 90 is provided in the ceramic substrate 11 is illustrated in FIG. 2, you may provide the porous part 90 in the base plate 50 as mentioned later (for example, 12(b), etc.).

The porous portion 90 has a porous region 91 (an example of a first porous region and a second porous region) having a plurality of holes 96 and a dense region 93 that is denser than the porous region 91 (first dense). region, an example of a second dense region). The porous region 91 is configured to allow gas to flow. A gas flows through each of the plurality of holes 96 . The dense region 93 is a region having fewer holes 96 compared to the porous region 91 , or a region having substantially no holes 96 . The porosity (percent: %) of the dense region 93 is lower than the porosity (%) of the porous region 91 . The density (grams/cubic centimeter: g/cm 3 ) of the dense region 93 is higher than the density (g/cm 3 ) of the porous region 91 . Since the dense region 93 is dense compared to the porous region 91 , for example, the rigidity (mechanical strength) of the dense region 93 is higher than that of the porous region 91 .

The porosity of the dense region 93 is, for example, a ratio of the volume of the space (hole 96 ) included in the dense region 93 to the total volume of the dense region 93 . The porosity of the porous region 91 is, for example, a ratio of the volume of the space (hole 96 ) included in the porous region 91 to the total volume of the porous region 91 . For example, the porosity of the porous region 91 is 5% or more and 40% or less, preferably 10% or more and 30% or less, and the porosity of the dense region 93 is 0% or more and 5% or less.

The porous portion 90 has a columnar shape (eg, a columnar shape). In addition, the porous region 91 is columnar (for example, columnar shape). The dense region 93 is in contact with the porous region 91 or is continuous with the porous region 91 . As shown in FIG.2(b), when projected on the plane (XY plane) perpendicular|vertical with respect to the Z direction, the dense area|region 93 surrounds the outer periphery of the porous area|region 91. As shown in FIG. The dense region 93 has a cylindrical shape (eg, a cylindrical shape) surrounding the side surface 91s of the porous region 91 . In other words, the porous region 91 is formed so as to penetrate the dense region 93 in the Z direction. The gas flowing into the through hole 15 from the gas introduction path 53 is supplied to the groove 14 through the plurality of holes 96 formed in the porous region 91 .

By providing the porous portion 90 having such a porous region 91 , the resistance to arc discharge can be improved while ensuring the flow rate of the gas flowing through the through hole 15 . In addition, the rigidity (mechanical strength) of the porous portion 90 can be improved by having the dense region 93 .

When the porous portion 90 is provided in the ceramic dielectric substrate 11 , the porous portion may be integrated with the ceramic dielectric substrate 11 , for example. The state in which two members are integrated is a state in which two members are chemically coupled. A material (eg, adhesive) for fixing one member to the other member is not provided between the two members. That is, in this example, no other member such as an adhesive is provided between the porous portion 90 and the ceramic dielectric substrate 11, and the porous portion 90 and the ceramic dielectric substrate 11 are integrated.

In this way, when the porous part 90 is fixed to the ceramic dielectric substrate 11 by being integrated with the ceramic dielectric substrate 11, compared with the case where the porous part 90 is fixed to the ceramic dielectric substrate 11 with an adhesive or the like. Accordingly, the strength of the electrostatic chuck 110 may be improved. For example, deterioration of the electrostatic chuck due to corrosion or erosion of the adhesive does not occur.

When the porous portion 90 and the ceramic dielectric substrate 11 are integrated, a force may be applied from the ceramic dielectric substrate 11 to the side surface of the outer periphery of the porous portion 90 . On the other hand, when a plurality of holes are formed in the porous portion 90 to ensure the flow rate of the gas, the mechanical strength of the porous portion 90 decreases. For this reason, when the porous portion 90 is integrated with the ceramic dielectric substrate 11 , there is a risk that the porous portion 90 may be damaged by a force applied from the ceramic dielectric substrate 11 to the porous portion 90 .

On the other hand, since the porous portion 90 has the dense region 93, the rigidity (mechanical strength) of the porous portion 90 can be improved, and the porous portion 90 is formed with a ceramic dielectric substrate 11 and can be unified.

In addition, in the embodiment, the porous portion 90 may not necessarily be integrated with the ceramic dielectric substrate 11 . For example, as shown in Fig. 11, the porous portion 90 may be attached to the ceramic dielectric substrate using an adhesive.

Further, the dense region 93 is positioned between the inner wall 15w of the ceramic dielectric substrate 11 forming the through hole 15 and the porous region 91 . That is, the porous region 91 is formed on the inner side of the porous portion 90 , and the dense region 93 is formed on the outer side. By forming the dense region 93 on the outside of the porous portion 90 , the rigidity with respect to the force applied to the porous portion 90 from the ceramic dielectric substrate 11 may be improved. Accordingly, the porous portion 90 and the ceramic dielectric substrate 11 can be easily integrated. In addition, for example, when the adhesive member 61 (refer to FIG. 11) is provided between the porous part 90 and the ceramic dielectric substrate 11, the gas passing through the porous part 90 can pass through the adhesive member 61. It is possible to suppress the contact with the dense region 93 . Thereby, deterioration of the adhesive member 61 can be suppressed. In addition, since the porous region 91 is formed inside the porous portion 90, the through-hole 15 of the ceramic dielectric substrate 11 is prevented from being blocked by the dense region 93, thereby securing the flow rate of the gas. .

The thickness of the dense region 93 (length L0 between the side surface 91s of the porous region 91 and the side surface 93s of the dense region 93) is, for example, 100 µm or more and 1000 µm or less.

As the material of the porous portion 90, a ceramic having insulating properties is used. The porous portion 90 (each of the porous region 91 and the dense region 93 ) is at least one of _{aluminum oxide (Al 2} O ₃ ), titanium oxide (TiO ₂ ), and yttrium oxide (Y ₂ O _{3 ).} includes Thereby, the high dielectric breakdown voltage and high rigidity of the porous part 90 can be acquired.

For example, the porous portion 90 has as a main component any one of aluminum oxide, titanium oxide, and yttrium oxide.

In this case, the purity of the aluminum oxide of the ceramic dielectric substrate 11 may be higher than that of the aluminum oxide of the porous portion 90 . In this way, performance such as plasma resistance of the electrostatic chuck 110 can be secured, and the mechanical strength of the porous part 90 can be secured. As an example, sintering of the porous part 90 is accelerated|stimulated by containing a trace amount of additives in the porous part 90, and it becomes possible to control pores and to ensure mechanical strength.

In the present specification, the purity of ceramics such as aluminum oxide of the ceramic dielectric substrate 11 can be measured by fluorescence X-ray analysis, ICP-AES method (Inductively Coupled Plasma-Atomic Emission Spectrometry: high frequency inductively coupled plasma emission spectrometry), etc. have.

For example, the material of the porous region 91 and the material of the dense region 93 are the same. However, the material of the porous region 91 may be different from the material of the dense region 93 . The composition of the material of the porous region 91 may be different from the composition of the material of the dense region 93 .

3A and 3B are schematic diagrams illustrating the porous portion 90 of the electrostatic chuck according to the embodiment.

Fig. 3(a) is a plan view of the porous portion 90 seen along the Z direction, and Fig. 3(b) is a cross-sectional view of the porous portion 90 in the ZY plane.

As shown to Fig.3 (a) and Fig.3 (b), in the porous part 90, the porous area|region 91 has several coarse part 94 (an example of a 1st coarse part, a 2nd coarse part) and It has a dense portion 95 (an example of a first dense portion, a second dense portion). You may have a plurality of dense portions 95 . Each of the plurality of sparse portions 94 has a plurality of holes 96 . The dense portion 95 is denser than the loose portion 94 . That is, the dense portion 95 is a portion having fewer pores compared to the sparse portion 94 , or a portion having substantially no holes. The dimension of the dense portion 95 in the X or Y direction is smaller than the dimension of the dense region 93 in the X or Y direction. The porosity of the dense portion 95 is lower than the porosity of the loose portion 94 . Therefore, the density of the dense portion 95 is higher than the density of the sparse portion 94 . The porosity of the dense portion 95 may be equal to the porosity of the dense region 93 . Since the dense portion 95 is dense compared to the coarse portion 94 , the rigidity of the dense portion 95 is higher than that of the loose portion 94 .

The porosity of one sparse part 94 is a ratio of the volume of the space (hole 96) contained in the sparse part 94 which occupies for the total volume of the sparse part 94, for example. The porosity of the dense portion 95 is, for example, a ratio of the volume of the space (hole 96 ) included in the dense portion 95 to the total volume of the dense portion 95 . For example, the porosity of the sparse portion 94 is 20% or more and 60% or less, preferably 30% or more and 50% or less, and the porosity of the dense portion 95 is 0% or more and 5% or less.

Each of the plurality of sparse portions 94 extends in the Z direction. For example, each of the plurality of sparse portions 94 has a columnar shape (a columnar shape or a polygonal columnar shape), and is formed so as to penetrate the porous region 91 in the Z direction. The dense portion 95 is located between the plurality of loose portions 94 . The dense portion 95 is in the shape of a wall partitioning the sparse portions 94 adjacent to each other. As shown in FIG.3(a), when it projects on the plane (XY plane) perpendicular|vertical with respect to the Z direction, the dense part 95 is formed so that each outer periphery of the some coarse part 94 may be enclosed. The dense portion 95 is continuous with the dense region 93 on the outer periphery of the porous region 91 .

The number of the sparse parts 94 formed in the porous area|region 91 is 50 or more and 1000 or less, for example. As shown to Fig.3 (a), when it projects on the plane (XY plane) perpendicular|vertical with respect to the Z direction, some coarse part 94 mutually has substantially the same magnitude|size. For example, when projected on a plane (XY plane) perpendicular to the Z direction, the plurality of coarse portions 94 are isotropically and uniformly dispersed in the porous region 91 . For example, the distance between the adjacent coarse portions 94 (that is, the thickness of the dense portions 95) is approximately constant.

For example, when projected on a plane (XY plane) perpendicular to the Z direction, the side surface 93s of the dense region 93 and the coarse portion 94 closest to the side surface 93s among the plurality of coarse portions 94 . ), the distance L11 is 100 µm or more and 1000 µm or less.

In this way, by forming the plurality of sparse portions 94 and the dense portion 95 more dense than the sparse portions 94 in the porous region 91, the plurality of holes are randomly dispersed three-dimensionally in the porous region. Compared with the case in which the porous portion 90 is resistant to arc discharge and the flow rate of the gas flowing through the through hole 15 is secured, the rigidity of the porous portion 90 can be improved.

For example, when the porosity of the porous region 91 increases, the gas flow rate increases, while resistance to arc discharge and rigidity decrease. In contrast, arc discharge even when the porosity is increased by forming a dense portion 95 in the porous region 91 in which the dimension in the X or Y direction is smaller than the dimension in the X or Y direction of the dense region 93 . It is possible to suppress the decrease in resistance to and rigidity.

For example, when projected on a plane (XY plane) perpendicular to the Z direction, a minimum circle, ellipse, or polygon including all of the plurality of coarse portions 94 is assumed. The inner side of the circle, ellipse, or polygon may be considered as the porous region 91 , and the outer side of the circle, ellipse, or polygon may be considered as the dense region 93 .

As described above, the porous portion 90 includes a plurality of sparse portions 94 having a plurality of holes 96 including a first hole 96 and a second hole 96 , and the sparse portion 94 . It may have a dense portion 95 with a density higher than the density of . Each of the plurality of sparse portions 94 extends in the Z direction. The dense portion 95 is located between the plurality of coarse portions 94 . The sparse portion 94 has a wall portion 97 (examples of the first wall portion and the second wall portion) formed between the plurality of holes 96 (between the first hole 96 and the second hole 96). . In the X-direction or Y-direction, the minimum value of the dimension of the wall portion 97 can be made smaller than the minimum value of the dimension of the dense portion 95 . In this way, since the porous part 90 has the coarse part 94 and the dense part 95 extending in the Z direction, the resistance to arc discharge and the gas flow rate are ensured while the mechanical strength of the porous part 90 is ensured. Strength (rigidity) can be improved.

In addition, as illustrated in FIG. 5 to be described later, the dimensions of the plurality of holes 96 formed in each of the plurality of sparse portions 94 in the X direction or the Y direction are smaller than the dimensions of the dense portion 95 . can do. In this way, since the dimensions of the plurality of holes 96 can be made sufficiently small, the resistance to arc discharge can be further improved.

In addition, the aspect ratio (aspect ratio) of the some hole 96 formed in each of the some sparse part 94 can be 30 or more and 10000 or less. In this way, resistance to arc discharge can be further improved. More preferably, the lower limit of the aspect ratio (aspect ratio) of the plurality of holes 96 is 100 or more, and the upper limit is 1600 or less.

In addition, in the X direction or the Y direction, the dimensions of the plurality of holes 96 formed in each of the plurality of sparse portions 94 may be 1 micrometer or more and 20 micrometers or less. In this way, since the holes 96 extending in one direction with a dimension of 1 to 20 micrometers of the holes 96 can be arranged, high resistance to arc discharge can be realized.

In addition, as illustrated in FIGS. 6 (a) and (b) to be described later, when projected on a plane (XY plane) perpendicular to the Z direction, the hole 96a is located in the center of the sparse portion 94, Among the plurality of holes 96, the number of holes 96b to 96g adjacent to the hole 96a and surrounding the hole 96a can be six. In this way, in planar view, it becomes possible to arrange|position a some hole with high isotropy and high density. Thereby, the rigidity of the porous part 90 can be improved, ensuring resistance to arc discharge and the flow rate of the flowing gas.

4 is a schematic plan view illustrating the porous portion 90 of the electrostatic chuck according to the embodiment.

4 : shows a part of the porous part 90 seen along the Z direction, and corresponds to the enlarged view of FIG.3(a).

When projected on a plane (XY plane) perpendicular to the Z direction, each of the plurality of sparse portions 94 is a substantially hexagonal (approximately regular hexagon). When projected on a plane (XY plane) perpendicular to the Z direction, the plurality of sparse portions 94 include a sparse portion 94a located in the center of the porous region 91 and six pieces surrounding the sparse portion 94a. It has a sparse portion 94 (the sparse portions 94b to 94g).

The sparse portions 94b to 94g are adjacent to the sparse portion 94a. The sparse portions 94b to 94g are formed closest to the sparse portion 94a among the plurality of sparse portions 94 .

The sparse part 94b and the sparse part 94c are arranged in the X direction with the sparse part 94a. That is, the sparse portion 94a is positioned between the sparse portion 94b and the sparse portion 94c.

The length L1 (diameter of the coarse part 94a) along the X direction of the coarse part 94a is longer than the length L2 along the X direction between the coarse part 94a and the coarse part 94b, and the coarse part 94a It is longer than the length L3 along the X direction between the sparse portion 94c.

Further, each of the length L2 and the length L3 corresponds to the thickness of the dense portion 95 . That is, the length L2 is the length along the X direction of the dense portion 95 between the coarse portion 94a and the loose portion 94b. The length L3 is the length along the X direction of the dense portion 95 between the open portions 94a and 94c. The length L2 and the length L3 can be made into substantially the same thing. For example, length L2 can be made into 0.5 times or more and 2.0 times or less of length L3.

In addition, the length L1 can be made into a thing substantially equal to the length L4 (diameter of the coarse part 94b) along the X direction of the coarse part 94b. The length L1 may be substantially equal to the length L5 (diameter of the coarse portion 95c) along the X direction of the coarse portion 94c. For example, each of the length L4 and the length L5 can be 0.5 times or more and 2.0 times or less the length L1.

As such, the sparse portion 94a is adjacent to and surrounded by six sparse portions 94 of the plurality of sparse portions 94 . That is, when it projects on the plane (XY plane) perpendicular|vertical with respect to the Z direction, in the center part of the porous area|region 91, the number of the coarse part 94 adjacent to one coarse part 94 is six. Thereby, in planar view, it is possible to arrange|position the some sparse part 94 with high isotropy and high density. Thereby, the rigidity of the porous part 90 can be improved, ensuring resistance to arc discharge and the flow rate of the gas flowing through the through hole 15 . In addition, variations in resistance to arc discharge, variations in the flow rate of gas flowing through the through holes 15 , and variations in rigidity of the porous portion 90 can be suppressed.

The diameter (length L1, L4, L5, etc.) of the sparse part 94 is 50 micrometers or more and 500 micrometers or less, for example. The thickness of the dense portion 95 (length L2 or L3, etc.) is, for example, 10 µm or more and 100 µm or less. The diameter of the sparse portion 94 is greater than the thickness of the dense portion 95 . Also, as described above, the thickness of the dense portion 95 is smaller than the thickness of the dense region 93 .

5 is a schematic plan view illustrating the porous portion 90 of the electrostatic chuck according to the embodiment.

5 shows a part of the porous part 90 seen along the Z direction. 5 is an enlarged view of the periphery of one sparse portion 94 .

As shown in FIG. 5 , in this example, the sparse portion 94 has a plurality of holes 96 and a wall portion 97 formed between the plurality of holes 96 .

Each of the plurality of holes 96 extends in the Z direction. Each of the plurality of holes 96 has a capillary shape (one-dimensional capillary structure) extending in one direction, and penetrates the sparse portion 94 in the Z direction. The wall part 97 is a wall shape which partitions the mutually adjacent holes 96. As shown in FIG. 5 , when projected on a plane (XY plane) perpendicular to the Z direction, the wall portion 97 is formed so as to surround each outer periphery of the plurality of holes 96 . The wall portion 97 is continuous with the dense portion 95 on the outer periphery of the coarse portion 94 .

The number of holes 96 formed in one sparse part 94 is 50 or more and 1000 or less, for example. As shown in FIG. 5, when it projects on the plane (XY plane) perpendicular|vertical with respect to the Z direction, the some hole 96 mutually has substantially the same size. For example, when projected on a plane (XY plane) perpendicular to the Z direction, the plurality of holes 96 are isotropically and uniformly dispersed in the sparse portion 94 . For example, the distance between the adjacent holes 96 (that is, the thickness of the wall portion 97) is approximately constant.

In this way, by arranging the holes 96 extending in one direction in the sparse portion 94, the high resistance to arc discharge is reduced with a small deviation compared to the case in which a plurality of holes are three-dimensionally randomly dispersed in the sparse portion. can be realized

Here, the "capillary-shaped structure" of the plurality of holes 96 will be further described.

In recent years, for the purpose of high integration of semiconductor devices, thinning of circuit line width and miniaturization of circuit pitch are further progressing. A further high power is applied to the electrostatic chuck, so that the temperature control of the object W at a higher level is required. From such a background, it is calculated|required while ensuring sufficient gas flow rate, suppressing arc discharge reliably also in a high-power environment, and controlling the flow volume with high precision. In the electrostatic chuck 110 according to the present embodiment, in the ceramic plug (porous portion 90) conventionally provided to prevent arc discharge in the helium supply hole (gas introduction passage 53), the hole diameter ( The diameter of the hole 96) is made small, for example, to a level of several to tens of micrometers (the details of the diameter of the hole 96 will be described later). When the diameter becomes small to this level, there is a fear that the gas flow rate control becomes difficult. Therefore, in the present invention, for example, the shape of the hole 96 is further devised so as to follow the Z direction. Specifically, conventionally, arc discharge prevention was achieved by securing a flow rate in a relatively large hole and complicating the shape three-dimensionally. On the other hand, in this invention, arc discharge prevention is achieved by making the hole 96 fine to the level of several to several tens of micrometers in diameter, for example, Conversely, flow rate is ensured by simplifying the shape. That is, the present invention was conceived based on a completely different idea from the prior art.

In addition, the shape of the sparse part 94 is not limited to a hexagon, A circle (or an ellipse) or another polygon may be sufficient. For example, when projected on a plane (XY plane) perpendicular to the Z direction, a minimum circle, ellipse, or polygon including all of the plurality of holes 96 arranged at intervals of 10 µm or less is assumed. The inner side of the circle, ellipse, or polygon may be considered as the coarse portion 94 , and the outer side of the circle, ellipse, or polygon may be considered as the dense portion 95 .

6A and 6B are schematic plan views illustrating the porous portion 90 of the electrostatic chuck according to the embodiment.

6(a) and 6(b) are enlarged views showing a part of the porous portion 90 seen along the Z direction and showing the hole 96 in one loose portion 94 .

As shown in Fig. 6(a) , when projected onto a plane (XY plane) perpendicular to the Z direction, the plurality of holes 96 include a hole 96a located in the center of the sparse portion 94, a hole ( It has six holes 96 (holes 96b to 96g) surrounding 96a. The holes 96b to 96g are adjacent to the hole 96a. The holes 96b to 96g are the holes 96 closest to the hole 96a among the plurality of holes 96 .

The hole 96b and the hole 96c are arranged in the X direction with the hole 96a. That is, the hole 96a is located between the hole 96b and the hole 96c.

For example, the length L6 (diameter of the hole 96a) along the X direction of the hole 96a is longer than the length L7 along the X direction between the hole 96a and the hole 96b, and between the hole 96a and the hole 96b. longer than the length L8 along the X direction between (96c).

In addition, each of the length L7 and the length L8 corresponds to the thickness of the wall portion 97 . That is, the length L7 is the length along the X direction of the wall portion 97 between the hole 96a and the hole 96b. The length L8 is the length along the X direction of the wall portion 97 between the hole 96a and the hole 96c. Length L7 and length L8 can be made into about the same thing. For example, length L7 can be made into 0.5 times or more and 2.0 times or less of length L8.

In addition, the length L6 can be made substantially equal to the length L9 (diameter of the hole 96b) along the X direction of the hole 96b. The length L6 may be substantially equal to the length L10 (diameter of the hole 96c) along the X direction of the hole 96c. For example, each of the length L9 and the length L10 can be 0.5 times or more and 2.0 times or less the length L6.

For example, when the diameter of the hole is small, resistance to arc discharge and rigidity are improved. On the other hand, when the diameter of the hole is large, the flow rate of the gas can be increased. The diameter (length L6, L9, L10, etc.) of the hole 96 is, for example, 1 micrometer (micrometer) or more and 20 micrometers or less. By arranging holes extending in one direction with a diameter of 1 to 20 µm, high resistance to arc discharge can be realized with little variation. More preferably, the diameter of the hole 96 is 3 µm or more and 10 µm or less.

Here, the measuring method of the diameter of the hole 96 is demonstrated. An image is acquired at a magnification of 1000 times or more using a scanning electron microscope (for example, Hitachi High-Technologies Corporation, S-3000). Using commercially available image analysis software, the equivalent circle diameter for 100 holes is calculated for the holes 96 , and the average value is taken as the diameter of the holes 96 .

It is more preferable to suppress variations in diameters of the plurality of holes 96 . By reducing the variation in diameter, it becomes possible to more precisely control the flow rate and dielectric breakdown voltage of the flowing gas. As the deviation of the diameters of the plurality of holes 96 , the cumulative distribution of diameters corresponding to 100 circles obtained in the calculation of the diameters of the holes 96 can be used. Specifically, the concept of particle diameter D50 (median diameter) when the cumulative distribution is 50 vol% and the particle diameter D90 when the cumulative distribution is 90 vol%, which are generally used for particle size distribution measurement, is applied, and the horizontal axis is the pore diameter (㎛), Using the cumulative distribution graph of the holes 96 with the vertical axis as the relative hole volume (%), the hole diameter (corresponding to the D50 diameter) when the cumulative distribution of the hole diameter is 50 vol% (equivalent to the D50 diameter) and the cumulative distribution when the cumulative distribution is 90 vol% Find the hole diameter (corresponding to the D90 diameter). It is preferable that the deviation of the diameters of the plurality of holes 96 be suppressed to such an extent that the relationship D50:D90≤1:2 is satisfied.

The thickness (length L7, L8, etc.) of the wall part 97 is 1 micrometer or more and 10 micrometers or less, for example. The thickness of the wall portion 97 is thinner than the thickness of the dense portion 95 .

As such, the hole 96a is surrounded by adjacent six holes 96 of the plurality of holes 96 . That is, when projected on a plane (XY plane) perpendicular to the Z direction, one hole 96 and the number of adjacent holes 96 are six at the center of the sparse portion 94 . This makes it possible to arrange the plurality of holes 96 with high isotropy and high density in plan view. Thereby, the rigidity of the porous part 90 can be improved, ensuring resistance to arc discharge and the flow rate of the gas flowing through the through hole 15 . In addition, variations in resistance to arc discharge, variations in the flow rate of gas flowing through the through holes 15 , and variations in rigidity of the porous portion 90 can be suppressed.

6( b ) shows another example of the arrangement of the plurality of holes 96 in the sparse portion 94 . As shown in FIG.6(b), in this example, the some hole 96 is arrange|positioned concentrically around the hole 96a. This makes it possible to arrange a plurality of holes with high isotropy and high density when projected onto a plane (XY plane) perpendicular to the Z direction.

In addition, each of the lengths L0 to L10 can be measured by observation using a microscope such as a scanning electron microscope.

Evaluation of the porosity in this specification is demonstrated. Here, evaluation of the porosity in the porous part 90 is taken as an example and demonstrated.

An image similar to the plan view of Fig.3 (a) is acquired, and ratio R1 of the some sparse part 94 which occupies for the porous area|region 91 by image analysis is computed. A scanning electron microscope (for example, Hitachi High-Technologies Corporation, S-3000) is used for image acquisition. A BSE image is acquired with an acceleration voltage of 15 kV and a magnification of 30 times. For example, the image size is 1280x960 pixels, and the image gradation is 256 gradations.

Image analysis software (for example, Win-ROOF Ver6.5 (MITANI CORPORATION)) is used for calculation of the ratio R1 of the some coarse part 94 which occupies for the porous area|region 91.

The ratio R1 using Win-ROOF Ver6.5 can be calculated as follows.

Let the evaluation range ROI1 (refer to Fig. 3(a)) be the smallest circle (or ellipse) including all the coarse portions 94 .

The binarization process by a single threshold value (for example, 0) is performed, and the area S1 of evaluation range ROI1 is computed.

The binarization process by two threshold values (for example, 0 and 136) is performed, and area S2 of the sum of the some sparse part 94 in evaluation range ROI1 is computed. At this time, a filling process in the sparse part 94 and deletion of a small area area considered to be noise (threshold value: 0.002 or less) are performed. In addition, the two threshold values are appropriately adjusted according to the brightness and contrast of the image.

As the ratio of the area S2 to the area S1, the ratio R1 is calculated. That is, the ratio R1 (%) = (area S2)/(area S1) x 100.

In embodiment, ratio R1 of the some sparse part 94 which occupies for the porous area|region 91 is 40 % or more and 70 % or less, for example, Preferably they are 50 % or more and 70 % or less. The ratio R1 is, for example, about 60%.

The same image as the top view of FIG. 5 is acquired, and ratio R2 of the some hole 96 which occupies for the sparse part 94 by image analysis is computed. Ratio R2 corresponds to the porosity of the sparse part 94, for example. A scanning electron microscope (for example, Hitachi High-Technologies Corporation, S-3000) is used for image acquisition. A BSE image is acquired with an acceleration voltage of 15 kV and a magnification of 600 times. For example, the image size is 1280x960 pixels, and the image gradation is 256 gradations.

Image analysis software (for example, Win-ROOF Ver6.5 (MITANI CORPORATION)) is used for calculation of the ratio R2 of the some hole 96 which occupies for the sparse part 94.

The ratio R1 using Win-ROOF Ver6.5 can be calculated as follows.

Let evaluation range ROI2 (refer FIG. 5) be the hexagon which approximates the shape of the coarse part 94. All the holes 96 formed in one coarse portion 94 are included within the evaluation range ROI2.

The binarization process by a single threshold value (for example, 0) is performed, and the area S3 of evaluation range ROI2 is computed.

The binarization process by two threshold values (for example, 0 and 96) is performed, and area S4 of the sum of the some hole 96 in evaluation range ROI2 is computed. At this time, a filling process in the hole 96 and deletion of a small area area considered to be noise (threshold value: 1 or less) are performed. In addition, the two threshold values are appropriately adjusted according to the brightness and contrast of the image.

As the ratio of the area S4 to the area S3, the ratio R2 is calculated. That is, the ratio R2(%)=(area S4)/(area S3)×100.

In the embodiment, the ratio R2 (porosity of the open portion 94) of the plurality of holes 96 to the sparse portion 94 is, for example, 20% or more and 60% or less, preferably 30% or more and 50% is below. The ratio R2 is, for example, about 40%.

The porosity of the porous region 91 is, for example, the product of the ratio R1 of the plurality of sparse portions 94 in the porous region 91 and the ratio R2 of the plurality of holes 96 in the sparse portion 94 considerable For example, when the ratio R1 is 60% and the ratio R2 is 40%, the porosity of the porous region 91 can be calculated to be about 24%.

By using the porous portion 90 having the porous region 91 having such a porosity, the dielectric strength can be improved while ensuring the flow rate of the gas flowing through the through hole 15 .

Similarly, the porosity of the ceramic dielectric substrate 11 and the porous portion 70 can be calculated. In addition, it is preferable to select suitably the magnification of a scanning electron microscope in the range of several tens to several thousand times according to an observation object, for example.

7(a), (b) is a schematic diagram illustrating the porous part 90 by another embodiment.

Fig. 7(a) is a plan view of the porous portion 90 seen along the Z direction, and Fig. 7(b) corresponds to an enlarged view of a part of Fig. 7(a).

As shown to Fig.7(a) and Fig.7(b), in this example, the planar shape of the sparse part 94 is circular. In this way, the planar shape of the sparse portion 94 may not be hexagonal.

8 is a schematic cross-sectional view illustrating an electrostatic chuck according to an embodiment.

Fig. 8 corresponds to an enlarged view of the region B shown in Fig. 2 . That is, FIG. 8 shows the vicinity of the interface F1 between the porous portion 90 (dense region 93 ) and the ceramic dielectric substrate 11 . In this example, aluminum oxide is used for the material of the porous portion 90 and the ceramic dielectric substrate 11 .

As shown in FIG. 8 , the porous portion 90 includes a first region 90p positioned on the ceramic dielectric substrate 11 side in the X or Y direction, and the first region 90p in the X or Y direction. has a continuous second region 90q. The first region 90p and the second region 90q are part of the dense region 93 of the porous portion 90 .

The first region 90p is positioned between the second region 90q and the ceramic dielectric substrate 11 in the X or Y direction. The first region 90p is a region of about 40 to 60 μm in the X direction or the Y direction from the interface F1. That is, the width W1 of the first region 90p along the X or Y direction (the length of the first region 90p in the direction perpendicular to the interface F1) is, for example, 40 μm or more and 60 μm. is below.

In addition, the ceramic dielectric substrate 11 includes a first substrate region 11p positioned on the side of the porous portion 90 (first region 90p) in the X-direction or the Y-direction, the first substrate region 11p; It has the 2nd board|substrate area|region 11q continuous in an X direction or a Y direction. The first region 90p and the first substrate region 11p are formed in contact with each other. The first substrate region 11p is located between the second substrate region 11q and the porous portion 90 in the X or Y direction. The first substrate region 11p is located from the interface F1 in the X or Y direction. It is a region of about 40 to 60 μm in the direction. That is, the width W2 of the first substrate region 11p along the X or Y direction (the length of the first substrate region 11p in the direction perpendicular to the interface F1) is, for example, 40 µm or more. 60 µm or less.

9A and 9B are schematic cross-sectional views illustrating an electrostatic chuck according to an embodiment.

FIG. 9A is an enlarged view of a part of the first area 90p shown in FIG. 8 . Fig. 9B is an enlarged view of a part of the first substrate region 11p shown in Fig. 8 .

As shown to Fig.9 (a), the 1st area|region 90p contains several particle|grains g1 (crystal grain). Moreover, as shown to FIG.9(b), the 1st board|substrate area|region 11p contains the some particle|grain g2 (crystal grain).

The average particle diameter (average value of the diameters of the plurality of particles g1) in the first region 90p is the average particle diameter (average value of the diameters of the plurality of particles g2) in the first substrate region 11p different from

Since the average particle diameter in the first region 90p and the average particle diameter in the first substrate region 11p are different, the crystal grains of the porous portion 90 at the interface F1 and the ceramic dielectric substrate 11 ) can improve the bonding strength (interfacial strength) of the grains. For example, peeling of the porous portion 90 from the ceramic dielectric substrate 11 and separation of crystal grains can be suppressed.

In addition, as an average particle diameter, the average value of the equivalent circle diameter of the crystal grain in the image of a cross section like FIG.9(a) and FIG.9(b) can be used. The equivalent circle diameter is the diameter of a circle having the same area as the area of the target planar shape.

It is also preferable that the ceramic dielectric substrate 11 and the porous portion 90 are integrated. The porous portion 90 is fixed to the ceramic dielectric substrate 11 by being integrated with the ceramic dielectric substrate 11 . Accordingly, the strength of the electrostatic chuck can be improved as compared with the case where the porous portion 90 is fixed to the ceramic dielectric substrate 11 with an adhesive or the like. For example, deterioration of the electrostatic chuck due to corrosion or erosion of the adhesive can be suppressed.

In this example, the average particle diameter in the first substrate region 11p is smaller than the average particle diameter in the first region 90p. When the grain diameter in the first substrate region 11p is small, the bonding strength between the porous portion 90 and the ceramic dielectric substrate can be improved at the interface between the porous portion 90 and the ceramic dielectric substrate. In addition, since the particle diameter in the first substrate region is small, the strength of the ceramic dielectric substrate 11 can be increased, and risks such as cracks due to stress generated during manufacturing or processing can be suppressed. For example, the average particle diameter in the 1st area|region 90p is 3 micrometers or more and 5 micrometers or less. For example, the average particle diameter in the 1st substrate area|region 11p is 0.5 micrometer or more and 2 micrometers or less. The average particle diameter in the first substrate region 11p is not less than 1.1 times and not more than 5 times the average particle diameter in the first region 90p.

In addition, for example, the average particle diameter in the 1st substrate area|region 11p is smaller than the average particle diameter in the 2nd board|substrate area|region 11q. In the first substrate region 11p formed in contact with the first region 90p, the interface strength between the first region 90p and the first region 90p is increased by an interaction such as diffusion with the first region 90p. It is preferable to make it high. On the other hand, in the second substrate region 11q, it is preferable that the original characteristics of the material of the ceramic dielectric substrate 11 are expressed. By making the average particle diameter in the first substrate region 11p smaller than the average particle diameter in the second substrate region 11q, interfacial strength is guaranteed in the first substrate region 11p, and the second substrate region The characteristics of the ceramic dielectric substrate 11 in (11q) can be made compatible.

The average particle diameter in the first region 90p may be smaller than the average particle diameter in the first substrate region 11p. Accordingly, at the interface between the porous portion 90 and the ceramic dielectric substrate, the bonding strength between the porous portion 90 and the ceramic dielectric substrate can be improved. Moreover, since the intensity|strength of the porous part 90 becomes high because the average particle diameter in the 1st area|region 90p is small, drop-off|omission of particle|grains at the time of a process can be suppressed and a particle can be reduced.

Further, in the same manner as described above, the average particle diameter in the first region 90p may be made smaller than the average particle diameter in the second substrate region 11q. In this way, the mechanical strength in the first region 90p can be improved.

Referring again to FIG. 2A , the description of the structure of the electrostatic chuck 110 is continued. As described above, the electrostatic chuck 110 may further include a porous portion 70 (a first porous portion and a second porous portion). The porous portion 70 does not have the plurality of coarse portions 94 and the plurality of dense portions 95 described with reference to FIGS. 3 to 7 . In this example, the porous portion 70 is provided on the base plate, and is disposed to face the gas introduction passage 53 . The porous part 70 can be provided between the porous part 90 and the gas introduction path 53 in the Z direction, for example. For example, the porous portion 70 is sandwiched between the ceramic dielectric substrate 11 side of the base plate 50 . As illustrated in FIG. 2A , for example, a spot facing portion 53a is formed on the ceramic dielectric substrate 11 side of the base plate 50 . The spot facing portion 53a is formed in a cylindrical shape. By appropriately designing the inner diameter of the spot facing portion 53a, the porous portion 70 is fitted to the spot facing portion 53a. In addition, as will be described later, the porous portion 70 may be provided on the ceramic substrate 11 .

In this example, the upper surface 70U of the porous portion 70 is exposed to the upper surface 50U of the base plate 50 . The upper surface 70U of the porous portion 70 faces the lower surface 90L of the porous portion 90 . In this example, a space SP is formed between the upper surface 70U of the porous portion 70 and the lower surface 90L of the porous portion 90 . The first porous portion may be any one of the porous portion 90 and the porous portion 70 . The second porous portion may be either the porous portion 90 or the porous portion 70 .

The porous portion 70 includes a porous region 71 (examples of a first porous region and a second porous region) having a plurality of pores, and a dense region 72 (first dense region, first dense region, first dense region) denser than the porous region 71 . 2 example) of a dense area. The porous region 71 is formed in a cylindrical shape (eg, cylindrical), and is fitted to the spot facing portion 53a. The shape of the porous portion 70 is preferably a cylindrical shape, but is not limited to a cylindrical shape. An insulating material is used for the porous portion 70 . The material of the porous portion 70 is, for example, Al ₂ O ₃ , Y ₂ O ₃ , ZrO ₂ , MgO, SiC, AlN, or Si ₃ N ₄ . The material of the porous section 70 may be a glass such as SiO _2. The material of the porous part 70 may be Al ₂ O ₃ -TiO ₂ , Al ₂ O ₃ -MgO, Al ₂ O ₃ -SiO ₂ , Al ₆ O ₁₃ Si ₂ , YAG, ZrSiO ₄ , or the like.

The porosity of the porous region 71 is, for example, 20% or more and 60% or less. The density of the porous region 71 is, for example, 1.5 g/cm 3 or more and 3.0 g/cm 3 or less. The gas such as He that has flowed through the gas introduction path 53 passes through the plurality of holes 71p of the porous region 71 and is sent from the through holes 15 formed in the ceramic dielectric substrate 11 to the grooves 14. lose

The dense region 72 has a portion made of, for example, a ceramic insulating film. A ceramic insulating film is formed between the porous region 71 and the gas introduction path 53 . The ceramic insulating film is denser than the porous region 71 . The porosity of the ceramic insulating film is, for example, 10% or less. The density of the ceramic insulating film is, for example, 3.0 g/cm 3 or more and 4.0 g/cm 3 or less. The ceramic insulating film is formed on the side surface of the porous part 70 .

As the material of the ceramic insulating film, for example, Al ₂ O ₃ , Y ₂ O ₃ , ZrO ₂ , MgO, etc. are used. As the material of the ceramic insulating film, Al ₂ O ₃ -TiO ₂ , Al ₂ O ₃ -MgO, Al ₂ O ₃ -SiO ₂ , Al ₆ O ₁₃ Si ₂ , YAG, ZrSiO _{4 ,} or the like may be used.

The ceramic insulating film can be formed, for example, on the side surface of the porous portion 70 by thermal spraying, PVD (Physical Vapor Deposition), CVD, sol-gel method, aerosol deposition method, or the like. The thickness of the ceramic insulating film is, for example, 0.05 mm or more and 0.5 mm or less.

The porosity of the ceramic dielectric substrate 11 is, for example, 1% or less. The density of the ceramic dielectric substrate 11 is, for example, 4.2 g/cm 3 .

The porosity in the ceramic dielectric substrate 11 and the porous portion 70 is measured by a scanning electron microscope as described above. Density is measured according to JIS C 2141 5.4.3.

When the porous portion 70 is fitted to the spot facing portion 53a of the gas introduction passage 53 , the ceramic insulating film 72 and the base plate 50 come into contact with each other. That is, the porous portion 70 having a high insulating porous region 71 and a dense region 73 between the through hole 15 for guiding a gas such as He into the groove 14 and the metal base plate 50 . ) is interposed. By using such a porous part 70, compared with the case where only the porous area|region 71 is formed in the gas introduction path 53, it becomes possible to exhibit high insulation.

In addition, the plurality of holes 71p formed in the porous portion 70 are three-dimensionally dispersed than the plurality of holes 96 formed in the porous portion 90, and the ratio of the holes penetrating in the Z direction is ), the porous portion 90 can be increased. Since a higher dielectric breakdown voltage can be obtained by providing the porous portion 70 having a plurality of three-dimensionally dispersed holes 71p, the occurrence of arc discharge can be effectively suppressed while facilitating the flow of gas. Further, as shown in Fig. 2(a), by providing the ceramic dielectric substrate 11 with the porous portion 90 having a large proportion of holes penetrating in the Z direction, for example, arc discharge even when the plasma density is high. can be more effectively suppressed.

The average value of the plurality of holes formed in the porous portion (second porous portion, porous portion 70 in FIG. 2A) provided in the base plate 50 is calculated as the average value of the porous portion provided in the ceramic dielectric substrate 11 ( It can be made larger than the average value of the some hole formed in the 1st porous part, (a porous part 90) in FIG.2(a). In this way, since the porous portion with a large hole diameter is provided on the gas introduction path 53 side, the flow of gas can be facilitated. Moreover, since the porous part with a small diameter of a hole is provided in the object side of adsorption|suction, generation|occurrence|production of an arc discharge can be suppressed more effectively.

Further, in the example in which the porous portion 70 is provided in the base plate 50 and the porous portion 90 is provided in the ceramic dielectric substrate 11, the diameters of the plurality of holes 71p formed in the porous portion 70 are The average value of can be made larger than the average value of the diameters of the plurality of holes 96 formed in the porous portion 90 . In this way, since the porous part 70 with a large diameter of a hole is provided, the smoothness of a gas flow can be aimed at. Moreover, since the porous part 90 with a small diameter of a hole is provided in the object side of adsorption|suction, generation|occurrence|production of an arc discharge can be suppressed more effectively.

Moreover, since the dispersion|variation in the diameter of a several hole can be made small, more effective suppression of arc discharge can be aimed at.

10 is a schematic cross-sectional view illustrating the porous portion 70 of the electrostatic chuck according to the embodiment.

10 is an enlarged view of a part of the cross section of the porous region 71 .

The plurality of holes 71p formed in the porous region 71 are three-dimensionally dispersed in the X direction, the Y direction, and the Z direction in the porous region 71 . In other words, the porous region 71 has a three-dimensional network structure in which the holes 71p are widened in the X-direction, Y-direction, and Z-direction. In the porous portion 70 , the plurality of holes 71p are dispersed in the porous region 71 , for example, randomly or uniformly.

Since the plurality of holes 71p are three-dimensionally dispersed, a part of the plurality of holes 71p is also exposed on the surface of the porous region 71 . Therefore, minute unevenness is formed on the surface of the porous region 71 . That is, the surface of the porous region 71 can be roughened. The surface roughness of the porous region 71 makes it easy to form, for example, a ceramic insulating film (dense region 72 ) on the surface of the porous region 71 . For example, the contact between the ceramic insulating film (dense region 72 ) and the porous region 71 is improved. In addition, peeling of the ceramic insulating film (dense region 72) can be suppressed.

The average value of the diameters of the plurality of holes 71p formed in the porous region 71 is, for example, larger than the average value of the diameters of the plurality of holes 96 formed in the porous region 91 . The diameter of the hole 71p is, for example, 10 µm or more and 50 µm or less. The flow rate of the gas flowing through the through hole 15 can be controlled (limited) by the porous region 91 having a small diameter of the hole 96 . Thereby, the variation in the gas flow rate due to the ceramic porous body 71 can be suppressed. The diameter of the hole 71p and the diameter of the hole 96 can be measured with a scanning electron microscope as described above.

11 is a schematic cross-sectional view illustrating the porous portion 90 according to another embodiment.

FIG. 11 illustrates the periphery of the porous part 90 similarly to FIG. 2( a ).

In this example, the porous portion 90 is provided on the ceramic dielectric substrate 11 . The porous part 70 is provided in the base plate 50 . That is, the porous part 90 is used for the 1st porous part. The porous part 70 is used for the 2nd porous part. In addition, the porous portion 90 may be provided on both the ceramic dielectric substrate 11 and the base plate 50 .

In this example, an adhesive member 61 (adhesive) is provided between the porous portion 90 and the ceramic dielectric substrate 11 . The porous portion 90 is adhered to the ceramic dielectric substrate 11 by an adhesive member 61 . For example, the adhesive member 61 is provided between the side surface of the porous portion 90 (side surface 93s of the dense region 93 ) and the inner wall 15w of the through hole 15 . The porous portion 90 and the ceramic dielectric substrate 11 may not be in contact with each other.

For the adhesive member 61, for example, a silicone adhesive is used. The adhesive member 61 is, for example, an elastic member having elasticity. The elastic modulus of the adhesive member 61 is, for example, lower than the elastic modulus of the dense region 93 of the porous portion 90 and lower than the elastic modulus of the ceramic dielectric substrate 11 .

In the structure in which the porous part 90 and the ceramic dielectric substrate 11 are bonded by the adhesive member 61, the adhesive member 61 is applied to the difference between the thermal contraction of the porous part 90 and the thermal contraction of the ceramic dielectric substrate 11 It can be used as a cushioning material for

12(a), (b) are schematic cross-sectional views illustrating the porous portion 90 according to another embodiment.

In the above-described embodiment (see FIG. 2 ), the porous portion 90 is provided on the ceramic dielectric substrate 11 , and the porous portion 70 is provided on the base plate 50 .

However, when the porous portion 90 is used, either one of the porous portion provided on the base plate 50 and the porous portion provided on the ceramic dielectric substrate 11 may be omitted.

For example, in the example shown in FIG. In this way, the flow resistance of the gas such as He supplied to the porous portion 90 can be reduced.

Moreover, in the example shown in FIG.12(b), the hole part 15b is formed in the ceramic dielectric board|substrate 11, and the porous part 90 is provided in the base plate 50. As shown in FIG. In this way, the flow resistance of the gas such as He supplied to the porous portion 90 can be reduced.

In addition, as shown in Fig. 12(a), at least a part of the edge 53b of the opening on the ceramic dielectric substrate 11 side of the gas introduction path 53 can be formed in a curved shape. For example, so-called "R-chamfering" can be implemented to the edge 53b of the opening of the gas introduction path 53. In this case, the edge 53b of the opening of the gas introduction passage 53 may be configured to have a curved shape with a radius of about 0.2 millimeters (mm).

As described above, the base plate 50 is formed of a metal such as aluminum. Therefore, if the edge of the opening of the gas introduction passage 53 is square, electric field concentration tends to occur, and there is a fear that arc discharge is likely to occur.

In the present embodiment, since at least a part of the edge 53b of the opening of the gas introduction passage 53 is curved, the concentration of the electric field can be suppressed, and thus arc discharge can be reduced.

13(a) to (d) are schematic cross-sectional views illustrating porous portions 90a and 70a according to another embodiment.

14A to 14C are schematic cross-sectional views illustrating porous portions 90a and 90b according to another embodiment.

13 (a) is a ceramic dielectric substrate 11 provided with a porous portion 90a in which the dense area 93 of the porous portion 90 is changed, and the dense area of the porous portion 70 on the base plate 50 ( 72) is an example in which the modified porous part 70a is provided. 14(a) shows a ceramic dielectric substrate 11 and a base plate 50, a porous portion 90a in which the dense region 93 of the porous portion 90 is changed, and a dense region 72 of the porous portion 70. It is an example in the case where this changed porous part 70b is provided respectively.

13(a), 13(b), and 14(a), in the porous portion 90a provided on the ceramic dielectric substrate 11, the porous region 91 has a dense portion 92a. have more That is, the porous portion 90a is obtained by adding a dense portion 92a to the above-described porous portion 90 .

13(a) and 13(b) , the dense portion 92a may have a plate shape (eg, a disk shape). As shown in Fig. 14(a), the dense portion 92a may have a columnar shape (for example, a columnar shape). The material of the dense portion 92a can be, for example, the same as the material of the dense region 93 described above. The dense portion 92a is denser than the porous region 91 . The density of the dense portion 92a and the dense region 93 may be about the same. When projected onto a plane (XY plane) perpendicular to the Z direction, the dense portion 92a and the hole 15b overlap. It is more preferable that the porous area|region 91 and the hole part 15b are comprised so that it may not overlap. According to this configuration, the generated current tends to flow by bypassing the dense portion 92a. Therefore, since the distance (conduction path) through which an electric current flows can be lengthened, an electron becomes difficult to accelerate|accelerate, and by extension, generation|occurrence|production of an arc discharge can be suppressed.

In addition, when projected on a plane (XY plane) perpendicular to the Z direction, the size of the dense portion 92a is the same as the size of the hole 15b, or the size of the dense portion 92a is the hole 15b. It is preferable to make it larger than the dimension of . In this way, the current flowing through the hole 15b can be guided to the dense portion 92a. Therefore, the distance (conduction path) through which the current flows can be effectively lengthened.

In this example, the porous region 91 is formed around the dense portion 92a when projected onto a plane perpendicular to the Z direction. A sufficient gas flow can be ensured since the porous area|region 91 is used as the periphery of the porous area|region 91 while the resistance to arc discharge is improved by arranging the dense part 92a at the position opposing the hole part 15b. That is, reduction of arc discharge and smoothing of the flow of gas can be made compatible.

As shown in Fig. 13(a), the length along the Z direction of the dense portion 92a may be smaller than the length along the Z direction of the porous portion 90a, and as shown in Fig. 14(a), the porous portion ( 90a) may be approximately equal to the length along the Z direction. When the length along the Z direction of the dense portion 92a is increased, the occurrence of arc discharge can be more effectively suppressed. When the length along the Z direction of the dense portion 92a is smaller than the length along the Z direction of the porous portion 90a, the flow of gas can be facilitated.

The dense portion 92a may be constituted by a compact body having substantially no holes, or may be constituted to have a plurality of holes if it is denser than the porous region 91 . When the dense portion 92a has a plurality of holes, it is preferable to make the diameter of the hole smaller than the diameter of the hole in the porous region 91 . The porosity (%: %) of the dense portion 92a may be lower than the porosity (%) of the porous region 91 . Therefore, the density (gram/cubic centimeter: g/cm 3 ) of the dense portion 92a can be made higher than the density (g/cm 3 ) of the porous region 91 . The porosity of the dense portion 92a can be, for example, the same as the porosity of the dense region 93 described above.

Here, the arc discharge is often generated when a current flows in the hole 15b from the ceramic dielectric substrate 11 side toward the base plate 50 side. Therefore, if the dense portion 92a having a low porosity is formed in the vicinity of the hole 15b, as shown in Figs. try to flow by bypassing it. Therefore, since the distance (conduction path) through which the electric current 200 flows can be lengthened, an electron becomes difficult to accelerate|accelerate, and by extension, generation|occurrence|production of an arc discharge can be suppressed.

Further, as shown in Fig. 13(a), for example, in the porous portion 70 provided on the base plate 50, the porous region 71 further includes a dense portion 92b. can also be used

Further, as shown in FIG. 14A , the porous portion 90a may be provided on the ceramic dielectric substrate 11 and the porous portion 70b may be provided on the base plate 50 . In the porous portion 70b, the porous region 71 further has a dense portion 92b. That is, the porous portion 70b is obtained by adding a dense portion 92b to the above-described porous portion 70 .

That is, the dense portion 92b may be further added to the porous portion 70 or the porous portion 90 installed on the base plate 50 .

At least one dense portion 92b may be formed. As shown in Figs. 13(c) and 14(b), a plurality of dense portions 92b having a plate shape (eg, disk shape) or columnar shape (eg, column shape) may be formed. . As shown to Fig.13(d) and Fig.14(c), the dense part 92b which shows annular (for example, annular shape) or cylindrical shape (for example, cylindrical shape) can also be formed. The material, density, porosity, etc. of the dense portion 92b may be the same as those of the dense portion 92a.

At least a portion of the dense portion (for example, the dense portion 92b) included in the porous portion provided on the base plate 50 when projected onto a plane (XY plane) perpendicular to the Z direction is provided on the ceramic dielectric substrate 11 It is preferable to make it overlap with the dense part (for example, the dense part 92a) which the porous part has. According to such a configuration, for example, in the porous portion 90a (porous portion on the side of the ceramic dielectric substrate 11), the current that bypasses the dense portion 92a flows through the porous portions 70 and 90b in which the dense portion 92b is formed. ) (the porous part on the base plate 50 side), the dense part 92b is further added without flowing through the porous region (for example, the porous regions 71 and 91) of the porous part provided on the base plate 50 side. turn around and try to flow. Therefore, since the distance (conduction path) through which an electric current flows can be made longer, electrons become more difficult to accelerate, and by extension, generation|occurrence|production of an arc discharge can be suppressed effectively.

15(a), (b) are schematic cross-sectional views illustrating a porous part according to another embodiment.

As shown to Fig.15 (a), (b), when it projects on the plane (XY plane) perpendicular|vertical with respect to the Z direction, it can be made to overlap the dense part 92a and the dense part 92b. Moreover, you may make it the dense part 92a and the dense part 92b contact when it projects on the plane (XY plane) perpendicular|vertical with respect to the Z direction. In addition, if there is a slight gap between the dense portion 92a and the dense portion 92b when projected onto a plane (XY plane) perpendicular to the Z direction, a current flows between the dense portion 92a and the dense portion 92b. can be restrained Therefore, as long as the current can be suppressed from flowing between the dense portion 92a and the dense portion 92b, a gap may be formed between the dense portion 92a and the dense portion 92b.

In this way, it is possible to suppress the current flowing through the porous portion 90a from flowing through the porous portion 70a without passing through the dense portion 92b. Therefore, the distance (conduction path) through which the current flows can be effectively lengthened.

Moreover, as shown to Fig.15 (a), (b), when projecting on the plane (XY plane) perpendicular|vertical with respect to the Z direction, it is preferable to make the dense part 92b and the dense area|region 93 overlap. In addition, you may make it the dense part 92b and the dense area|region 93 contact when it projects on the plane (XY plane) perpendicular|vertical with respect to the Z direction. In this way, since the distance (conduction path) through which the electric current flows can be made longer, electrons become more difficult to accelerate, and furthermore, generation|occurrence|production of an arc discharge can be suppressed effectively.

16 is a schematic cross-sectional view illustrating an electrostatic chuck according to another embodiment.

17(a) and (b) correspond to enlarged views of the region C shown in FIG. 16 .

16 and 17 (a) and (b) , the electrostatic chuck 110a includes a ceramic dielectric substrate 11c and a base plate 50 . That is, no porous portion (porous portion 70 or porous portion 90) is provided in the ceramic dielectric substrate 11c.

A plurality of holes 16 are directly formed in the ceramic dielectric substrate 11c. The plurality of holes 16 can be formed in the ceramic dielectric substrate 11c by, for example, laser irradiation or ultrasonic processing. In this example, one end of the plurality of holes 16 is located on the face 14a of the groove 14 . The other ends of the plurality of holes 16 are located on the second main surface 11b of the ceramic dielectric substrate 11c. That is, the plurality of holes 16 penetrate the ceramic dielectric substrate 11c in the Z direction.

As shown to Fig.17 (a), (b), the base plate 50 can be provided with a porous part (for example, the porous part 70a). Further, the base plate 50 may be provided with a porous portion 90b. Further, as illustrated in FIG. 12A , the gas introduction passage 53 may be formed without the porous portion 70 or the porous portion 90 provided on the base plate 50 .

Further, as shown in Figs. 17(a) and (b), the upper surface 70U of the porous portion 70 (or the upper surface 90U of the porous portion 90) provided on the base plate 50 and the ceramic dielectric substrate ( The second main surface 11b of 11c) may not be in contact. Also, as described above, at least a portion of the edge 53b of the opening of the gas introduction passage 53 on the ceramic dielectric substrate 11c side can be configured as a curved line.

When the plurality of holes 16 are formed in the ceramic dielectric substrate 11c, the gas supplied between the back surface of the object W loaded on the electrostatic chuck 110a and the first main surface 11a including the groove 14 It is possible to improve the resistance to arc discharge while securing the flow rate of

The length of the dense portion 92b along the Z direction may be smaller than the length of the porous portions 70a and 90b along the Z direction. In addition, the length along the Z direction of the dense portion 92b may be substantially equal to the length along the Z direction of the porous portions 70a and 90b. If the length along the Z direction of the dense portion 92b is shortened, the gas flow can be facilitated. When the length along the Z direction of the dense portion 92b is increased, the occurrence of arc discharge can be more effectively suppressed.

When projected on a plane (XY plane) perpendicular to the Z direction, at least one of the plurality of holes 16 may overlap the dense portion 92b. The material, density, porosity, etc. of the plurality of dense portions 92b are as described above, for example.

As shown in FIG. 17A , a porous portion 70a having a plurality of dense portions 92b may be provided in the base plate 50 . As shown in FIG.17(b), the porous part 90b which has the some dense part 92b may be provided in the base plate 50. As shown in FIG.

18 is a schematic cross-sectional view illustrating a plurality of holes 16h according to another embodiment.

The plurality of holes 16h may be formed by irradiating a laser or ultrasonic processing to the ceramic dielectric substrate 11 .

As shown in FIG. 18 , at least one of the plurality of holes 16h formed in the ceramic dielectric substrate 11 has a first portion 16h1 opening in the groove portion 14 and a first portion 16h1 opening in the second main surface 11b. It may have two parts 16h2. In the X direction or the Y direction, the dimension of the first part 16h1 may be smaller than the dimension of the second part 16h2 . In the X-direction or Y-direction, at least one of the plurality of holes 16h can make the opening dimension D4 of the groove 14 on the face 14a side smaller than the opening dimension D3 on the base plate 50 side. In addition, although the hole 16h which has a stepped structure was illustrated in FIG. 18, it can also be set as the hole 16h which has a tapered structure. For example, the opening dimension D4 can be 0.01 millimeter (mm) - 0.1 millimeter (mm) in diameter. For example, the opening dimension D3 can be about 0.15 millimeters (mm) - 0.2 millimeters (mm) in diameter. When the opening dimension D4 becomes smaller than the opening dimension D3, generation|occurrence|production of an arc discharge can be suppressed effectively.

In addition, the aspect ratio (aspect ratio) of the hole 16h can be 3-60, for example. In calculating the aspect ratio, "vertical" is, for example, the length in the Z direction of the hole 16h in FIG. 18, and "horizontal" is the upper surface (surface 14a) of the hole 16h. Let it be the average length of the length of the X direction of the hole 16h of and the length of the X direction of the hole 16h in the lower surface (2nd main surface 11b) of the hole 16h. In addition, optical microscopes, such as a laser microscope and a factory microscope, a digital microscope, etc. can be used for measurement of the length of the X direction of the hole 16h.

In addition, the opening dimension D4 can be made smaller than the length L1 (L4 of the open part 94b, the length L5 of the open part 94c) of the sparse part 94a illustrated in FIG.

19A and 19B are schematic cross-sectional views illustrating the shape of the opening portion of the hole 16 .

Fig. 19(b) corresponds to an enlarged view of the region D shown in Fig. 19(a). In FIG. 19( a ), there is no portion of the opening dimension D3 of FIG. 18 in the hole 16 . That is, the opening size of the hole 16 corresponds to the opening size D4 in FIG. 18 .

19(a), (b), the edge 16i of the opening on the first main surface 11a side of the hole 16 (the surface 14a side of the groove 14) is the hole 16 It can be inclined more gently than the edge 16j of the opening on the side of the 2nd main surface 11b. In this example, at least one of the plurality of holes 16 has an edge 16i of the opening on the groove 14 side of the hole 16 and a surface 14a of the groove 14 on the second main surface 11b side. When α is the angle formed by α, and the angle formed between the edge 16j of the opening on the second main surface 11b side of the hole 16 and the second main surface 11b is β, “α<β” . In this way, the concentration of the electric field can be suppressed, and by extension, the arc discharge can be reduced. In addition, in this example, the edge 16i is comprised with a straight line. However, the edge 16i may be comprised by a curved line, and may be comprised by a straight line and a curved line. When the edge 16i and the edge 16j are curved, the radius of curvature of the edge 16i may be larger than the radius of curvature of the edge 16j. When the edge 16i and the edge 16j are composed of straight lines and curved lines, at least one of the relationship between the linear portions and the relationship between the curved portions may satisfy the above-described relationship.

When the edge 16i is more gently inclined than the edge 16j, generation of chipping or the like and electric field concentration can be suppressed. Therefore, generation|occurrence|production of an arc discharge can be suppressed more effectively.

In addition, although the shape of the opening part of the hole 16 was illustrated as an example, the case of the hole 16h which has a stepped structure and a tapered structure is also the same.

20 is a schematic cross-sectional view illustrating an electrostatic chuck according to another embodiment.

Fig. 20 corresponds to an enlarged view of the region C shown in Fig. 16 .

Each of the plurality of holes 16 illustrated in Fig. 17(a) extends approximately in the Z direction. On the other hand, at least one of the plurality of holes 16 illustrated in FIG. 20 may be inclined with respect to the Z direction. If at least one of the plurality of holes 16 extends in a direction inclined with respect to the Z direction, it is considered that electrons are less likely to be accelerated when an electric current flows through the hole 16 . Therefore, generation|occurrence|production of an arc discharge can be suppressed effectively. According to the knowledge obtained by the present inventors, when the angle θ inclined with respect to the Z direction is set to 5° or more and 30° or less, preferably 5° or more and 15° or less, the arc discharge can be reduced without reducing the diameter of the hole 16. occurrence can be suppressed.

In addition, although the case of the hole 16 was illustrated as an example, the case of the hole 16h which has a stepped structure and a tapered structure is also the same.

The hole 16 inclined with respect to the Z direction may be directly formed in the ceramic dielectric substrate 11c by irradiating a laser or ultrasonic processing. Therefore, the region in which the at least one hole 16 inclined with respect to the Z direction is formed contains the same material as the ceramic dielectric substrate 11 .

21 is a schematic cross-sectional view illustrating an electrostatic chuck according to another embodiment.

Fig. 21 corresponds to an enlarged view of the region C shown in Fig. 16 .

As shown in FIG. 21, as for the porous part 90b, the porous area|region 91 further has the dense part 92b. That is, the porous portion 90b is obtained by adding a dense portion 92b to the above-described porous portion 90 . That is, the dense portion 92b may be further added to the porous portion 70 or the porous portion 90 installed on the base plate 50 .

When projected on a plane (XY plane) perpendicular to the Z direction, at least one of the openings on the dense portion 92b side of the plurality of holes 16 may overlap the dense portion 92b. The material, density, porosity, etc. of the plurality of dense portions 92b are as described above, for example.

22 is a schematic cross-sectional view illustrating an electrostatic chuck according to another embodiment.

Fig. 23 corresponds to an enlarged view of the region E shown in Fig. 22 .

Fig. 24 is an enlarged view showing another embodiment of the region E shown in Fig. 22 .

22 , 23 , and 24 , the electrostatic chuck 110b includes a ceramic dielectric substrate 11d and a base plate 50 . The ceramic dielectric substrate 11d is provided with a porous portion 90b or a porous portion 90a.

A plurality of holes 16 are formed in the ceramic dielectric substrate 11d. The plurality of holes 16 can be formed in the ceramic dielectric substrate 11d by, for example, laser irradiation or ultrasonic processing. In this example, one end of the plurality of holes 16 is located on the face 14a of the groove 14 . The other ends of the plurality of holes 16 are located on the bottom surface of the hole portion 15c. That is, the plurality of holes 16 penetrate the ceramic dielectric substrate 11d in the Z direction.

23 , at least one of the plurality of holes 16 can overlap the dense portion 92b when projected onto a plane (XY plane) perpendicular to the Z direction. The material, density, porosity, etc. of the dense portion 92b are as described above, for example.

As shown in FIG. 24 , when projected on a plane (XY plane) perpendicular to the Z direction, at least one of the plurality of holes 16 can overlap the dense portion 92a. The material, density, porosity, etc. of the dense portion 92a are as described above, for example.

(processing unit)

25 is a schematic diagram illustrating the processing apparatus 200 according to the present embodiment.

25 , the processing apparatus 200 may include an electrostatic chuck 110 , a power source 210 , a medium supply unit 220 , and a supply unit 230 .

The power source 210 is electrically connected to the electrode 12 formed on the electrostatic chuck 110 .

The power supply 210 can be, for example, a DC power supply. The power supply 210 applies a predetermined voltage to the electrode 12 . In addition, a switch for switching the application of the voltage and the stop of the application of the voltage may be provided in the power supply 210 .

The medium supply unit 220 is connected to an input path 51 and an output path 52 . The medium supply unit 220 may supply, for example, a liquid serving as a cooling medium or an insulating medium.

The medium supply unit 220 includes, for example, an accommodation unit 221 , a control valve 222 , and a discharge unit 223 .

The storage unit 221 may be, for example, a tank or factory piping for storing liquid. In addition, a cooling device or a heating device for controlling the temperature of the liquid may be installed in the accommodating part 221 . A pump or the like for discharging the liquid may be provided in the receiving unit 221 .

The control valve 222 is connected between the input path 51 and the accommodating part 221 . The control valve 222 may control at least one of a flow rate and a pressure of the liquid. In addition, the control valve 222 may switch between supply of a liquid and stop of supply.

The discharge part 223 is connected to the output path 52 . The discharge unit 223 may be a tank or a drain pipe for recovering the liquid discharged from the output path 52 . In addition, the discharge part 223 is not necessarily required, and you may make it supply the liquid discharged|emitted from the output path 52 to the storage part 221. FIG. In this way, since a cooling medium or a thermal insulation medium can be circulated, resource saving can be aimed at.

The supply unit 230 includes a gas supply unit 231 and a gas control unit 232 .

The gas supply unit 231 may be a high-pressure cylinder containing gas such as helium, factory piping, or the like. In addition, although the case where one gas supply part 231 is provided was illustrated, you may make it provide the some gas supply part 231.

The gas control unit 232 is connected between the plurality of gas supply paths 53 and the gas supply unit 231 . The gas controller 232 may control at least one of a flow rate and a pressure of a gas. Also, the gas control unit 232 may further have a function of switching between supply of gas and stop of supply. The gas control unit 232 can be, for example, a massflow controller, a massflow meter, or the like.

As shown in Fig. 25, a plurality of gas control units 232 can be provided. For example, the gas control unit 232 may be provided for each of a plurality of regions of the first main surface 11a. In this way, the gas to be supplied can be controlled for each of a plurality of regions. In this case, the gas control unit 232 may be provided for each of the plurality of gas supply paths 53 . In this way, gas control in a plurality of regions can be performed more precisely. In addition, although the case where the some gas control part 232 is provided was illustrated, as long as the gas control part 232 can independently control the supply of the gas in a some supply system, one rental may be sufficient.

Here, the means for holding the object W includes a vacuum chuck or a mechanical chuck. However, vacuum chucks cannot be used in an environment where the pressure is lower than atmospheric pressure. In addition, if the mechanical chuck is used, there is a risk that the object W may be damaged or particles may be generated. For this reason, for example, an electrostatic chuck is used in a processing apparatus used in a semiconductor manufacturing process or the like.

In such a processing device, it is necessary to isolate the processing space from the external environment. Therefore, the processing apparatus 200 may further include a chamber 240 . The chamber 240 may have, for example, an airtight structure capable of maintaining an atmosphere lowered than atmospheric pressure.

In addition, the processing device 200 may include a plurality of lift pins and a driving device for elevating the plurality of lift pins. When receiving the object W from the conveying apparatus or sending and receiving the object W to the conveying apparatus, the lift pin rises by the drive device and protrudes from the 1st main surface 11a. When the object W received from the conveying device is loaded onto the first main surface 11a, the lift pin is lowered by the driving device and accommodated in the ceramic dielectric substrate 11 .

In addition, various devices can be installed in the processing device 200 according to the content of the processing. For example, a vacuum pump for evacuating the inside of the chamber 240 can be installed. A plasma generating device for generating plasma may be installed in the chamber 240 . A process gas supply unit for supplying a process gas may be installed in the chamber 240 . A heater for heating the object W or the process gas may be installed in the chamber 240 . In addition, the apparatus installed in the processing apparatus 200 is not limited to what was illustrated. Since a known technology may be applied to the device installed in the processing device 200 , a detailed description thereof will be omitted.

As mentioned above, embodiment of this invention was described. However, the present invention is not limited to these techniques. For example, as the electrostatic chuck 110 , a configuration using a Coulomb force is exemplified, but a configuration using a Johnson-Rabeck force is also applicable. In addition, those skilled in the art to which design changes were appropriately added to the above-described embodiments are also included in the scope of the present invention as long as the characteristics of the present invention are provided. In addition, each element with which each embodiment mentioned above is equipped can be combined as long as it is technically possible, and combining these is also included in the scope of the present invention as long as the characteristics of the present invention are included.

11 Ceramic dielectric substrate 11a First main surface
11b second main surface 11c ceramic dielectric substrate
12 electrode 14 groove
14a Bottom surface 15 Through hole
15a hole 15b hole
15c hole 15c1 side
15d hole 16 hole
16h hole 16i edge
16j edge 50 base plate
53 gas inlet 53b edge
60 Joint 70 Porous
70a porous part 71 porous area
72 Dense area 90 Porous part
90a porous part 90b porous part
92a Dense section 92b Dense section
96 hole 110 electrostatic chuck
110a Electrostatic Chuck 200 Processing Unit
210 power 230 supply
W object

Claims (16)

a ceramic dielectric substrate having a first main surface on which an object to be adsorbed is loaded and a second main surface opposite to the first main surface;
a base plate supporting the ceramic dielectric substrate and having a gas introduction path;
a first porous portion provided on the ceramic dielectric substrate and facing the gas introduction path;
a second porous part installed on the base plate and facing the gas introduction path;
The ceramic dielectric substrate has a first hole positioned between the first main surface and the first porous portion,
the first porous portion has a first porous region having a plurality of pores and a first dense region denser than the first porous region, the first porous region further comprising at least one first dense portion;
the second porous portion has a second porous region having a plurality of pores, and a second dense region denser than the second porous region, the second porous region further comprising at least one second dense portion;
When projected from the base plate in a plane perpendicular to a first direction toward the ceramic dielectric substrate, the first dense portion and the first hole overlap, and at least a portion of the second dense portion and at least a portion of the first dense portion overlap or at least a portion of the second dense portion and at least a portion of the first dense portion are in contact with each other. The method of claim 1,
When projected onto a plane perpendicular to the first direction, the dimension of the first dense portion is the same as the dimension of the first hole, or the dimension of the first dense portion is larger than the dimension of the first hole electrostatic chuck. 3. The method according to claim 1 or 2,
The electrostatic chuck according to claim 1, wherein the second dense portion and the first dense region overlap or the second dense portion and the first dense region contact each other when projected onto a plane perpendicular to the first direction. 3. The method of claim 1 or 2,
the first porous region has a plurality of first sparse portions and a first dense portion;
the second porous region has a plurality of second sparse portions and a second dense portion;
the first sparse portion has the plurality of apertures;
The first dense portion has a higher density than that of the first coarse portion, and a dimension in a second direction orthogonal to the first direction is greater than a dimension of the first dense region in the second direction. small,
each of the plurality of first sparse portions extends in the first direction;
the first dense portion is located between the plurality of first coarse portions,
The first coarse portion has a first wall portion formed between the plurality of holes,
and a minimum value of the dimension of the first wall portion in the second direction is smaller than a minimum value of the dimension of the first dense portion. 5. The method of claim 4,
A dimension of the plurality of holes formed in each of the plurality of first coarse portions in the second direction is smaller than a dimension of the first dense portion, and/or a dimension of the plurality of second coarse portions in the second direction and a dimension of the plurality of holes formed in each of the portions is smaller than a dimension of the second dense portion. 5. The method of claim 4,
The electrostatic chuck according to claim 1 , wherein an aspect ratio of the plurality of holes formed in each of the plurality of first coarse portions and/or an aspect ratio of the plurality of holes formed in each of the plurality of second coarse portions is 30 or more. 5. The method of claim 4,
In the second direction, the dimensions of the plurality of holes formed in each of the plurality of first coarse portions and/or the dimensions of the plurality of holes formed in each of the plurality of second coarse portions are 1 micrometer or more and 20 micrometers. Electrostatic chuck, characterized in that the meter or less. 5. The method of claim 4,
The plurality of holes formed in the first coarse portion when viewed along the first direction include a first hole located in the center of the first coarse portion,
The number of holes adjacent to and surrounding the first hole among the plurality of holes is six, and/or
When viewed along the first direction, the plurality of holes formed in the second sparse portion includes a second hole located in a central portion of the second sparse portion,
The number of holes adjacent to the second hole and surrounding the second hole among the plurality of holes is six. 3. The method of claim 1 or 2,
The electrostatic chuck according to claim 1, wherein a length of the first dense portion in the first direction is smaller than a length of the first porous portion in the first direction. 3. The method according to claim 1 or 2,
The electrostatic chuck according to claim 1, wherein the first porous region is formed between the first dense portion and the base plate in the first direction. 3. The method according to claim 1 or 2,
The electrostatic chuck according to claim 1, wherein a length of the first dense portion in the first direction is the same as a length of the first porous portion in the first direction. 5. The method of claim 4,
The electrostatic chuck according to claim 1, wherein the plurality of first coarse portions are formed around the first dense portion when projected onto a plane perpendicular to the first direction. 3. The method of claim 1 or 2,
An average value of diameters of the plurality of holes formed in the second porous portion is greater than an average value of diameters of the plurality of holes formed in the first porous portion. 3. The method according to claim 1 or 2,
The electrostatic chuck according to claim 1, wherein at least a portion of an edge of the opening on the ceramic dielectric substrate side of the gas introduction path is formed in a curved shape. 3. The method according to claim 1 or 2,
The ceramic dielectric substrate has a first hole positioned between the first main surface and the first porous portion,
at least one of the ceramic dielectric substrate and the first porous portion has a second hole positioned between the first hole and the first porous portion;
The electrostatic chuck according to claim 1, wherein in a second direction orthogonal to the first direction, a dimension of the second hole is smaller than a dimension of the first porous part and larger than a dimension of the first hole. The electrostatic chuck according to claim 1 or 2;
and a supply unit capable of supplying a gas to a gas introduction path formed in the electrostatic chuck.

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