TW202034436A - Electrostatic chuck and processing device capable of reducing arc discharge - Google Patents

Abstract

The object of the present invention is to provide an electrostatic chuck and a processing device capable of reducing arc discharge. The solution of the present invention is to provide the first invention as an electrostatic chuck, which is characterized by comprising: a ceramic dielectric substrate having: a first principal surface on which a suction object is placed, and a second principal surface opposite to the first principal surface; a base plate, supporting the ceramic dielectric substrate and having a gas introducing channel; a first porous part, arranged on the ceramic dielectric substrate and opposite to the gas introducing channel; and a second porous part, arranged on the base plate and opposite to the gas introducing channel. The ceramic dielectric substrate has a first hole part located between the first principal surface and the first porous part. The first porous part 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 has at least one first dense part. The second porous part 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 has at least one second dense part. When projected on a plane perpendicular to a first direction from the base plate toward the ceramic dielectric substrate, the first dense part overlaps the first hole part, at least a part of the second dense part overlaps at least a part of the first dense part, or at least a part of the second dense part is in contact with at least a part of the first dense part.

Description

Electrostatic chuck and processing device

The aspect of the present invention relates to an electrostatic chuck and a processing device.

The electrode is sandwiched between ceramic dielectric substrates such as alumina, and the ceramic electrostatic chuck produced by firing is a built-in electrode that applies electricity for electrostatic adsorption. Adhere to substrates such as silicon wafers. In this type of electrostatic chuck, an inert gas such as helium (He) flows between the surface of the ceramic dielectric substrate and the back surface of the substrate of the object to be adsorbed to control the temperature of the substrate of the object to be adsorbed.

For example, in CVD (Chemical Vapor Deposition: Chemical Vapor Deposition) equipment, sputtering equipment, ion implantation equipment, etching equipment and other equipment for processing substrates, there are A device that increases the temperature of the substrate. In the electrostatic chuck used in such a device, an inert gas such as He flows between the ceramic dielectric substrate and the substrate to be adsorbed, and the inert gas is brought into contact with the substrate to suppress the temperature rise of the substrate.

In the electrostatic chuck that controls the substrate temperature by inert gas such as He, the ceramic dielectric substrate and the base plate supporting the ceramic dielectric substrate are provided with holes for introducing inert gas such as He (gas Lead-in road). Furthermore, the ceramic dielectric substrate is provided with a through hole communicating with the gas introduction passage of the bottom plate. Accordingly, the inert gas introduced from the gas introduction channel of the bottom plate is guided to the back surface of the substrate through the through hole of the ceramic dielectric substrate.

Here, when the substrate is processed in the device, discharge (arc discharge) from the plasma in the device toward the metal bottom plate may occur. The gas introduction channel of the bottom plate and the through hole of the ceramic dielectric substrate tend to become the discharge path. Therefore, there is a technology to improve the resistance to arc discharge (withstand voltage, etc.) by providing a porous part in the gas introduction channel of the bottom plate and the through hole of the ceramic dielectric substrate. For example, Patent Document 1 discloses an electrostatic chuck in which a ceramic sintered porous body is arranged in a gas introduction channel, and the structure and membrane pores of the ceramic sintered porous body are used as gas channels to improve the insulation in the gas introduction channel. In addition, Patent Document 2 discloses an electrostatic chuck in which a discharge prevention member for a process gas flow path for preventing discharge is formed of a ceramic porous body in a gas diffusion gap. Furthermore, Patent Document 3 discloses an electrostatic chuck in which a dielectric insert is provided as a porous dielectric such as alumina to reduce arc discharge. Furthermore, Patent Document 4 discloses a technique in which a plurality of pores communicating with a gas supply hole are provided on an electrostatic chuck made of aluminum nitride or the like by a laser processing method. In this type of electrostatic chuck, a further reduction in arc discharge is expected.

[Patent Document 1] Japanese Patent Application Publication No. 2010-123712 [Patent Document 2] Japanese Patent Application Publication No. 2003-338492 [Patent Document 3] Japanese Patent Application Publication No. 10-50813 [Patent Document 4] Japanese Patent Application Publication No. 2009-218592

The present invention is based on the recognition of such a subject, and its purpose is to provide an electrostatic chuck and a processing device that can reduce arc discharge.

The first invention is an electrostatic chuck, which is characterized by comprising: a ceramic dielectric substrate having: a first principal surface (principal surface) on which an object to be adsorbed is placed, and a second principal surface opposite to the aforementioned first principal surface Surface; a bottom plate, which supports the ceramic dielectric substrate and has a gas introduction channel; a first porous portion, which is arranged on the ceramic dielectric substrate and is opposed to the gas introduction channel; and a second porous portion, Disposed on the bottom plate and opposed to the gas inlet, the ceramic dielectric substrate has a first hole located between the first main surface and the first porous portion, and the first porous portion It has: a first porous region with a plurality of pores, and a first dense region denser than the first porous region, the first porous region further has at least one first dense part, and the second porous region The part has: a second porous region with a plurality of pores, and a second dense region denser than the aforementioned second porous region. The second porous region further has at least one second dense part, which is projected on the opposite When the bottom plate faces a plane perpendicular to the first direction of the ceramic dielectric substrate, the first dense part overlaps the first hole part, and at least a part of the second dense part overlaps with at least a part of the first dense part. Or, at least a part of the second dense part is in contact with at least a part of the first dense part.

According to this electrostatic chuck, the current flowing in the first porous part flows to the second dense part in a detour when flowing in the second porous part provided with the second dense part. Therefore, since the distance through which the current flows (conductive path) can be lengthened, electrons are difficult to be accelerated, and the occurrence of arc discharge can be suppressed.

The second invention is an electrostatic chuck, characterized in that: in the first invention, when projected on a plane perpendicular to the first direction, the size of the first dense portion is the same as the size of the first hole, or The size of the first dense portion is larger than the size of the aforementioned first hole portion.

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

The third invention is an electrostatic chuck, characterized in that, in the first or second invention, when projected on a plane perpendicular to the first direction, the second dense portion overlaps the first dense region, or the The second dense part is connected to the aforementioned first dense region.

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

The fourth invention is an electrostatic chuck, characterized in that, in any one of the first to third inventions, the first porous region has a plurality of first loose parts and first tight parts, and the first The sparse portion has the plurality of holes, the first dense portion has a higher density than the first sparse portion, the size in the second direction is smaller than the size of the first dense area in the second direction, Each of the plurality of first sparse portions extends in the first direction, the first dense portion is located between the plurality of first sparse portions, and the first sparse portion has a first sparse portion disposed between the plurality of holes. In the wall portion, in a second direction that is slightly orthogonal to the first direction, the minimum value of the size of the first wall portion is smaller than the minimum value of the size of the first compact portion.

According to this electrostatic chuck, since the first porous portion is provided with the first sparse portion and the first dense portion extending in the first direction, the resistance to arc discharge and the gas flow rate can be ensured, and the first porous portion can be increased. The mechanical strength (rigidity) of the pore mass.

The fifth invention is an electrostatic chuck characterized in that, in any one of the first to fourth inventions, the plurality of first sparse portions are provided in the second direction in the first direction. The size of the hole is smaller than the size of the first tight portion, and/or the size of the plurality of holes provided in each of the plurality of second sparse portions in the second direction is greater than the size of the second tight portion Still small.

According to the electrostatic chuck, since the size of the plurality of holes can be sufficiently reduced, the resistance to arc discharge can be further improved.

The sixth invention is an electrostatic chuck characterized in that, in any one of the first to fifth inventions, the aspect ratio of the plurality of holes provided in each of the plurality of first sparse portions is ), and/or the aspect ratio of the plurality of holes provided in each of the plurality of second sparse portions is 30 or more.

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

The seventh invention is an electrostatic chuck, characterized in that, in any one of the first to sixth inventions, the plurality of first sparse portions are arranged in the second direction in the first direction. The size of the hole and/or the size of the plurality of holes provided in each of the plurality of second sparse portions is 1 micrometer or more and 20 micrometers or less.

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

The eighth invention is an electrostatic chuck characterized in that, in any one of the first to seventh inventions, when viewed along the first direction, the plurality of holes provided in the first sparse portion include The first hole located at the center of the first sparse portion, the number of holes adjacent to and surrounding the first hole among the plurality of holes is 6, and/or when viewed along the first direction When, the plurality of holes provided in the second sparse part includes a second hole located at the center of the second sparse part, and the number of holes adjacent to the second hole and surrounding the second hole among the plurality of holes For 6.

According to this electrostatic chuck, it is possible to arrange a plurality of holes with high isotropy and high density in a plan view. Accordingly, the resistance to arc discharge and the flow rate of the flowing gas can be ensured, and the rigidity of the first porous portion can be improved.

The ninth invention is an electrostatic chuck characterized in that, in any one of the first to eighth inventions, the length of the first dense portion along the first direction is smaller than that of the first porous portion Its length along the aforementioned first direction.

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

The tenth invention is an electrostatic chuck characterized in that, in any one of the first to ninth inventions, in the first direction, the first dense part is provided between the first dense portion and the bottom plate. A porous area.

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

The eleventh invention is an electrostatic chuck characterized in that, in any one of the first to tenth inventions, the length of the first dense portion along the first direction and the first porous The lengths of the parts along the aforementioned first direction are approximately the same.

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

The twelfth invention is an electrostatic chuck characterized in that in any one of the first to eleventh inventions, when projected on a plane perpendicular to the first direction, the first dense part A plurality of the aforementioned first sparse parts are arranged around.

According to the electrostatic chuck, the air flow can be ensured and the occurrence of arc discharge can be effectively suppressed.

The thirteenth invention is an electrostatic chuck, characterized in that, in any one of the first to twelfth inventions, the ratio of the average diameter of the plurality of holes provided in the second porous portion The average value of the diameters of the plurality of pores provided in the first porous portion is still large.

According to this electrostatic chuck, since the second porous part with a large hole diameter is provided, the flow of gas can be smoothed. Furthermore, since the first porous portion with a small hole diameter is provided on the side of the object to be adsorbed, the occurrence of arc discharge can be suppressed more effectively.

The fourteenth invention is an electrostatic chuck characterized in that, in any one of the first to thirteenth inventions, at least a part of the edge of the opening on the ceramic dielectric substrate side of the gas introduction path is Curve composition.

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

The fifteenth invention is an electrostatic chuck, characterized in that, in any one of the first to fourteenth inventions, the ceramic dielectric substrate has a structure located on the first main surface and the first porous The first hole between the portions, at least any one of the ceramic dielectric substrate and the first porous portion has a second hole located between the first hole and the first porous portion, In a second direction that is slightly orthogonal to the first direction, the size of the second hole is smaller than the size of the first porous portion and larger than the size of the first hole.

According to the electrostatic chuck, the first porous part provided at the position opposite to the gas introduction channel can ensure the flow rate of the gas flowing through the first hole part and at the same time improve the resistance to arc discharge. Furthermore, since the second hole portion having a predetermined size is provided, most of the gas introduced into the first porous portion with a large size can be introduced to the first hole portion with a small size via the second hole. In other words, it is possible to reduce arc discharge and smooth gas flow.

The sixteenth invention is a processing device characterized by comprising: any one of the above-mentioned electrostatic chuck; and a supply part capable of supplying gas to a gas introduction path provided in the aforementioned electrostatic chuck. According to this processing device, arc discharge can be reduced.

According to aspects of the present invention, an electrostatic chuck and processing device that can reduce arc discharge can be provided.

Hereinafter, the embodiments of the present invention will be described with reference to the drawings. In addition, in each drawing, the same reference numeral is attached to the same constituent element, and detailed description is appropriately omitted. In addition, in each figure, the direction from the base plate 50 to the ceramic dielectric substrate 11 is regarded as the Z direction (corresponding to an example of the first direction), and one of the directions slightly orthogonal to the Z direction is regarded as the Y direction ( It corresponds to an example of the second direction), and a direction slightly orthogonal to the Z direction and the Y direction is regarded as the X direction (corresponding to an example of the second direction).

(Electrostatic chuck) Fig. 1 is a schematic cross-sectional view illustrating an electrostatic chuck related to this embodiment. As shown in FIG. 1, the electrostatic chuck 110 related to this embodiment includes a ceramic dielectric substrate 11, a bottom 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, for example, a flat substrate made of 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 alumina. The concentration of alumina in the ceramic dielectric substrate 11 is, for example, 99 atomic% (atomic %) or more and 100 atomic% or less. By using high-purity alumina, the plasma resistance of the ceramic dielectric substrate 11 can be improved. The ceramic dielectric substrate 11 has a first main surface 11a on which an object W (an object to be adsorbed) is placed, and a second main surface 11b on the opposite side of the first main surface 11a. The object W is, for example, a semiconductor substrate such as a silicon wafer.

Electrodes 12 are arranged on the ceramic dielectric substrate 11. The electrode 12 is arranged between the first main surface 11 a and the second main surface 11 b of the ceramic dielectric substrate 11. The electrode 12 is formed so as to be inserted into the ceramic dielectric substrate 11. A power source 210 is electrically connected to the electrode 12 via the connection portion 20 and the wiring 211. The power supply 210 can be used to apply a voltage for adsorption and holding to the electrode 12 to generate an electric charge on the first main surface 11a side of the electrode 12, and the object W can be adsorbed and held by electrostatic force.

The shape of the electrode 12 is a thin film along the first main surface 11 a and the second main surface 11 b 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 either a unipolar type or a bipolar type. The electrode 12 shown in FIG. 1 is a bipolar type, and two electrodes 12 are arranged on the same surface.

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

The bottom plate 50 is a member that supports the ceramic dielectric substrate 11. The ceramic dielectric substrate 11 is fixed on the bottom plate 50 through the joint 60 shown in FIG. 2(a). The bonding portion 60 can be cured with a silicone adhesive, for example

The bottom plate 50 is made of metal, for example. The bottom plate 50 is divided into, for example, an upper portion 50a and a lower portion 50b made of aluminum, and a connecting channel 55 is provided between the upper portion 50a and the lower portion 50b. One end of the connecting channel 55 is connected to the input channel 51, and the other end of the connecting channel 55 is connected to the output channel 52. The bottom plate 50 may have a spray part (not shown) at the end on the second main surface 11b side. The spray part is formed by, for example, thermal spraying. The spray part may constitute the end surface (top surface 50U) of the bottom plate 50 on the second main surface 11b side. The spraying part is arranged according to needs, and can also be omitted.

The bottom plate 50 also functions to adjust the temperature of the electrostatic chuck 110. For example, in the case of cooling the electrostatic chuck 110, a cooling medium (cooling medium) flows from the input channel 51 and flows out from the output channel 52 through the connecting channel 55. Accordingly, by absorbing the heat of the bottom plate 50 by the cooling medium, the ceramic dielectric substrate 11 mounted thereon can be cooled. On the other hand, when the electrostatic chuck 110 is kept warm, the heat preservation medium can also be put into the connecting channel 55. The heating body can also be built on the ceramic dielectric substrate 11 or the bottom plate 50. By adjusting the temperature of the bottom plate 50 or the ceramic dielectric substrate 11, the temperature of the object W held by the electrostatic chuck 110 can be adjusted.

Furthermore, on the first main surface 11a side of the ceramic dielectric substrate 11, dots 13 are provided as necessary, and grooves 14 are provided between the dots 13. That is, the first main surface 11a is a concave-convex surface and has concave and convex portions. The convex portion of the first main surface 11 a corresponds to the point 13, and the concave portion of the first main surface 11 a corresponds to the groove 14. The groove 14 may be formed by continuously extending in the XY plane, for example. According to this, 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 placed on the electrostatic chuck 110 and the first main surface 11 a including the groove 14.

The ceramic dielectric substrate 11 has a through hole 15 connected to the groove 14. The through hole 15 is provided from the second main surface 11b to the first main surface 11a. That is, the through hole 15 extends in the Z direction from the second main surface 11 b to the first main surface 11 a, and penetrates 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 dot 13 and the groove 14, the shape, etc., the temperature of the object W or the particles attached to the object W can be controlled in an appropriate state.

A gas introduction path 53 is provided on the bottom plate 50. The gas introduction path 53 is provided so as to penetrate the bottom plate 50, for example. The gas introduction path 53 may not penetrate the bottom plate 50 but branch from the middle of another gas introduction path 53 and may be provided to the ceramic dielectric substrate 11 side. In addition, the gas introduction passage 53 may be provided in a plurality of places on the bottom plate 50.

The gas introduction passage 53 communicates with the through hole 15. That is, the gas (helium (He), etc.) 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 provided between the object W and the first main surface 11 a including the groove 14 after passing through the through hole 15. According to this, the object W can be directly cooled by the gas.

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

Figure 2 (a) and (b) are schematic diagrams illustrating the electrostatic chuck related to the embodiment. FIG. 2(a) illustrates the porous part 90 and the periphery of the porous part 70 by way of example. Fig. 2(a) corresponds to an enlarged view of the area A shown in Fig. 1. Fig. 2(b) is a plan view illustrating the porous part 90.

2(c) and (d) are schematic cross-sectional views for illustrating the hole 15c and the hole 15d related to other embodiments.

In addition, in order to avoid becoming complicated, point 13 is omitted in FIGS. 2(a), (c), and (d) (for example, refer to FIG. 1) and 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 15 a is located on the second main surface 11 b of the ceramic dielectric substrate 11.

Furthermore, the ceramic dielectric substrate 11 may have a hole portion 15b located between the first main surface 11a and the porous portion 90 in the Z direction. The hole 15 b communicates with the hole 15 a and extends to the first main surface 11 a 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 15 b is located between the first main surface 11 a of the ceramic dielectric substrate 11 and the porous portion 90. The hole portion 15b is a connecting hole connecting the porous portion 90 and the groove 14. The diameter (length along the X direction) of the hole 15b is smaller than the diameter (length along the X direction) of the hole 15a. By providing the hole 15b with a small diameter, the freedom of design of the space formed between the ceramic dielectric substrate 11 and the object W (for example, the first main surface 11a including the groove 14) can be increased. For example, as shown in FIG. 2(a), the width (length along the X direction) of the groove 14 can be made shorter than the width (length along the X direction) of the porous portion 90. Accordingly, for example, the discharge formed in the space between the ceramic dielectric substrate 11 and the object W can be suppressed.

The diameter of the hole 15b is, for example, 0.05 millimeter (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 indirectly communicate with the hole 15a. That is, a hole portion 15c (second hole portion) connecting the hole portion 15a and the hole portion 15b may be provided. As illustrated in FIG. 2( a ), the hole 15 c may be provided in the ceramic dielectric substrate 11. As illustrated in FIG. 2(c), the hole portion 15c may also be provided in the porous portion 90. As illustrated in FIG. 2(d), the hole 15c may also be provided in the ceramic dielectric substrate 11 and the porous portion 90. In other words, at least any one of the ceramic dielectric substrate 11 and the porous portion 90 may have the hole portion 15 c located between the hole portion 15 b and the porous portion 90. In this case, if the hole 15c is provided in the ceramic dielectric substrate 11, the strength in the periphery of the hole 15c can be increased, and the occurrence of inclination or the like in the periphery of the hole 15c can be suppressed. Therefore, the occurrence of arc discharge can be suppressed more effectively. If the hole part 15c is provided in the porous part 90, the alignment of the hole part 15c and the porous part 90 becomes easy. Therefore, it becomes easier to coexist the reduction of arc discharge and the smoothing of gas flow. Each of the hole 15a, the hole 15b, and the hole 15c has a cylindrical shape extending in the Z direction, for example.

In this case, in the X direction or the Y direction, the size of the hole 15c can be made smaller than the size of the porous portion 90 and larger than the size of the hole 15b. According to the electrostatic chuck 110 related to the present embodiment, the porous portion 90 provided at the position opposite to the gas introduction path 53 can ensure the flow rate of the gas flowing through the hole portion 15b and improve the resistance to arc discharge. Sex. Furthermore, since the size of the hole portion 15c in the X direction or the Y direction is made larger than the size of the hole portion 15b, most of the gas introduced into the porous portion 90 with a large size can be introduced to the small size via the hole portion 15c.孔部15b. In other words, it is possible to reduce arc discharge and smooth gas flow.

As mentioned above, the ceramic dielectric substrate 11 has at least one groove 14 that opens on the first main surface 11 a and communicates with the through hole 15. Furthermore, the size of the hole 15c in the Z direction can be made smaller than the size of the groove 14 in the Z direction. Accordingly, the time for the gas to pass through the hole 15c can be shortened. In other words, the flow of gas can be smoothed, and the occurrence of arc discharge can be more effectively suppressed. Moreover, the size of the hole 15c can be made larger than the size of the groove 14 in the X direction or the Y direction. In this way, it becomes easy for the gas to flow into the groove 14. Therefore, it is possible to effectively cool the object W by the gas.

Furthermore, the arithmetic mean surface roughness Ra of the surface 15c1 (top surface) of the hole 15c on the first main surface 11a side is smaller than the arithmetic mean surface roughness Ra of the bottom surface 14a (the surface on the second main surface 11b side) of the groove 14 Better. Accordingly, since there are no large irregularities on the surface 15c1 of the hole portion 15c, the occurrence of arc discharge can be effectively suppressed.

Furthermore, it is preferable to make the arithmetic mean surface roughness Ra of the surface 14a on the second main surface 11b side of the groove 14 smaller than the arithmetic mean surface roughness Ra of the second main surface 11b. According to this, since there are no large irregularities on the surface 14a of the groove 14, the occurrence of arc discharge can be effectively suppressed.

Furthermore, the hole 15d (third hole) provided between the hole 15b and the hole 15c may be further provided. In the X direction or the Y direction, the size of the hole 15d can be larger than the hole 15b and smaller than the hole 15c. If the hole 15d is provided, the gas flow can be smoothed.

As mentioned above, the joint 60 may be provided between the ceramic dielectric substrate 11 and the bottom plate 50. In the Z direction, the size of the hole 15c can be made smaller than the size of the joint 60. Accordingly, the bonding strength between the ceramic dielectric substrate 11 and the bottom plate 50 can be improved. Furthermore, since the size of the hole portion 15c in the Z direction can be made smaller than the size of the joint portion 60, the gas flow can be smoothed, and the occurrence of arc discharge can be more effectively suppressed.

In this example, the porous part 90 is provided in the hole part 15a. Therefore, the top surface 90U of the porous portion 90 is not exposed on the first main surface 11a. That is, the top surface 90U of the porous portion 90 is located between the first main surface 11a and the second main surface 11b. On the other hand, the bottom surface 90L of the porous portion 90 is exposed on the second main surface 11b.

Next, the porous part 90 will be described. The porous portion 90 has a plurality of sparse portions 94 and a plurality of dense portions 95 described later. In addition, although the case where the porous part 90 is provided on the ceramic substrate 11 is illustrated in FIG. 2, as will be described later, the porous part 90 may be provided on the bottom plate 50 (for example, FIG. 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 pores 96, and a dense region 93 that is denser than the porous region 91 (first dense region, second An example of dense area). The porous region 91 is configured to allow gas to flow. Each system gas of the plurality of holes 96 flows inside. The dense area 93 is an area in which the pores 96 are less than the porous area 91 or an area that does not substantially have the pores 96. The porosity (percentage: %) of the dense region 93 is lower than the porosity (%) of the porous region 91. The density of the dense area 93 (g/cm3: g/cm ³ ) is higher than the density of the porous area 91 (g/cm ³ ). Since the dense region 93 is denser than the porous region 91, the rigidity (mechanical strength) of the dense region 93 is higher than the rigidity of the porous region 91, for example.

The porosity of the dense region 93 is, for example, the ratio of the volume of the space (pore 96) included in the dense region 93 to the entire volume of the dense region 93. The porosity of the porous region 91 is, for example, the ratio of the volume of the space (pore 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 part 90 has a columnar shape (for example, a columnar shape). Furthermore, the porous region 91 is columnar (for example, cylindrical). The dense area 93 is in contact with the porous area 91 or continues with the porous area 91. As shown in FIG. 2( b ), when projected on a plane (XY plane) perpendicular to the Z direction, the dense region 93 surrounds the outer periphery of the porous region 91. The dense region 93 has a cylindrical shape (for example, a cylindrical shape in the figure) surrounding the side 91s of the porous region 91. In other words, the porous region 91 is provided 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 provided in the porous region 91.

By providing the porous portion 90 having such a porous region 91, the gas flow rate flowing through the through hole 15 can be ensured, and the resistance to arc discharge can be improved. Furthermore, since the porous portion 90 has the dense region 93, the rigidity (mechanical strength) of the porous portion 90 can be improved.

When the porous portion 90 is provided on the ceramic dielectric substrate 11, the porous portion 90 may be integrated with the ceramic dielectric substrate 11, for example. The state where the two members are integrated refers to the state where the two members are chemically bonded. A material (for example, 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 is integrated with the ceramic dielectric substrate 11.

In this way, when the porous portion 90 is fixed to the ceramic dielectric substrate 11 by being integrated with the ceramic dielectric substrate 11, the porous portion 90 is fixed to the ceramic dielectric substrate 11 by an adhesive or the like. Compared with the situation, the strength of the electrostatic chuck 110 can be improved. For example, no deterioration of the electrostatic chuck due to corrosion or erosion of the adhesive occurs.

When the porous portion 90 and the ceramic dielectric substrate 11 are integrated, force is applied from the ceramic dielectric substrate 11 to the outer peripheral side surface of the porous portion 90. On the other hand, in order to ensure the flow rate of gas, when a plurality of holes are provided in the porous portion 90, the mechanical strength of the porous portion 90 is reduced. Therefore, when the porous portion 90 and the ceramic dielectric substrate 11 are integrated, the porous portion 90 may be damaged by the force applied to the porous portion 90 from the ceramic dielectric substrate 11.

In contrast, since the porous portion 90 has the dense region 93, the rigidity (mechanical strength) of the porous portion 90 can be increased, and the porous portion 90 and the ceramic dielectric substrate 11 can be integrated.

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 mounted on the ceramic dielectric substrate using an adhesive.

Furthermore, the dense region 93 is located between the inner wall 15w of the ceramic dielectric substrate 11 where the through hole 15 is formed and the porous region 91. That is, the porous region 91 is provided on the inner side of the porous portion 90, and the dense region 93 is provided on the outer side. By providing the dense region 93 on the outer side of the porous portion 90, the rigidity of the force applied to the porous portion 90 from the ceramic dielectric substrate 11 can be improved. According to this, the porous portion 90 and the ceramic dielectric substrate 11 can be easily integrated. Furthermore, for example, when the adhesive member 61 (see FIG. 11) is provided between the porous portion 90 and the ceramic dielectric substrate 11, the dense region 93 can prevent the gas passing through the porous portion 90 from contacting the adhesive member 61. Accordingly, the deterioration of the adhesive member 61 can be suppressed. Furthermore, by providing the porous region 91 inside the porous portion 90, the through hole 15 of the ceramic dielectric substrate 11 can be prevented from being blocked by the dense region 93, and the flow rate of gas can be ensured.

The thickness of the dense region 93 (the 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, an insulating ceramic is used. The porous portion 90 (each of the porous region 91 and the dense region 93) contains at least any one of aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), and yttrium oxide (Y ₂ O ₃ ). Accordingly, a high withstand voltage and high rigidity of the porous part 90 can be obtained.

For example, the porous part 90 contains any one of aluminum oxide, titanium oxide, and yttrium oxide as a main component. In this case, the purity of the alumina of the ceramic dielectric substrate 11 can be made higher than the purity of the alumina of the porous portion 90. Accordingly, performance such as plasma resistance of the electrostatic chuck 110 can be ensured, and the mechanical strength of the porous portion 90 can be ensured. As an example, the sintering of the porous portion 90 is promoted by including a trace amount of additives in the porous portion 90, thereby making it possible to control pores and ensure mechanical strength.

In this specification, the purity of the ceramics such as alumina of the ceramic dielectric substrate 11 can be determined by X-ray fluorescence analysis and ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). Pulp Atomic Emission Spectrometer Method) and so on.

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

3(a) and (b) are schematic diagrams illustrating the porous part 90 of the electrostatic chuck according to the embodiment. FIG. 3(a) is a plan view of the porous part 90 viewed along the Z direction, and FIG. 3(b) is a cross-sectional view of the porous part 90 on the ZY plane.

3(a) and 3(b), in the porous portion 90, the porous area 91 has a plurality of sparse portions 94 (an example of the first sparse portion and the second sparse portion) and a dense portion 95 (the first sparse portion). An example of a compact part and a second compact part). There may also be a plurality of compact portions 95. Each of the plurality of sparse portions 94 has a plurality of holes 96. The dense part 95 is denser than the sparse part 94. That is, the dense portion 95 is a portion having fewer holes than the sparse portion 94, or a portion having substantially no holes. The size of the dense portion 95 in the X direction or the Y direction is smaller than the size of the dense region 93 in the X direction or the Y direction. The porosity of the dense portion 95 is lower than the porosity of the sparse portion 94. Therefore, the density of the dense part 95 is higher than the density of the sparse part 94. The porosity of the dense portion 95 may also be the same as the porosity of the dense region 93. Since the dense part 95 is denser than the sparse part 94, the rigidity of the dense part 95 is higher than that of the sparse part 94.

The porosity of one sparse portion 94 is, for example, the ratio of the volume of the space (pore 96) included in the sparse portion 94 to the total volume of the sparse portion 94. The porosity of the compact portion 95 is, for example, the ratio of the volume of the space (pore 96) contained in the compact portion 95 to the entire volume of the compact portion 95. For example, the porosity of the sparse part 94 is 20% or more and 60% or less, preferably 30% or more and 50% or less, and the porosity of the dense part 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 is columnar (cylindrical or polygonal columnar), and is provided so as to penetrate the porous region 91 in the Z direction. The tight portion 95 is located between the plurality of sparse portions 94. The dense portion 95 is in the shape of a wall separating the sparse portions 94 adjacent to each other. As shown in FIG. 3(a), when projecting on a plane (XY plane) perpendicular to the Z direction, the dense portion 95 is provided so as to surround the outer periphery of each of the plurality of sparse portions 94. The dense portion 95 continues with the dense area 93 in the outer periphery of the porous area 91.

The number of sparse portions 94 provided in the porous region 91 is, for example, 50 or more and 1,000 or less. As shown in FIG. 3(a), when projecting on a plane (XY plane) perpendicular to the Z direction, the plurality of sparse portions 94 have substantially the same size as each other. For example, when projecting on a plane (XY plane) perpendicular to the Z direction, a plurality of sparse portions 94 are uniformly dispersed in the porous region 91 isotropically. For example, the distance between adjacent sparse portions 94 (that is, the thickness of the dense portion 95) is approximately constant.

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

In this way, by providing a plurality of sparse portions 94 and a dense portion 95 denser than the sparse portions 94 in the porous area 91, compared with the case where a plurality of holes are randomly dispersed in the porous area in three dimensions, the resistance to arc discharge can be ensured. It is possible to increase the rigidity of the porous portion 90 while maintaining the flexibility and the flow rate of the gas flowing through the through holes 15. For example, if the porosity of the porous region 91 increases, the flow rate of the gas increases, and on the other hand, the resistance to arc discharge and rigidity decrease. In contrast, by providing the porous region 91 with a dense portion 95 whose size in the X or Y direction is smaller than the size of the dense region 93 in the X or Y direction, even when the porosity is increased, the arc discharge can be suppressed. The resistance and rigidity are reduced.

For example, when projecting on a plane (XY plane) perpendicular to the Z direction, the smallest circle, ellipse, or polygon including all the sparse portions 94 is assumed. The inner side of the circle, ellipse, or polygon can be regarded as the porous area 91 and the outer side of the circle, ellipse, or polygon can be regarded as the dense area 93.

As described above, the porous portion 90 may have a plurality of sparse portions 94 having a plurality of pores 96 including the first hole 96 and the second hole 96; and a dense portion 95 having a density higher than that of the sparse portion 94. Each of the plurality of sparse portions 94 extends in the Z direction. The tight portion 95 is located between the plurality of sparse portions 94. The sparse portion 94 has a wall portion 97 (examples of the first wall portion and the second wall portion) provided between the plurality of holes 96 (between the first hole 96 and the second hole 96). In the X direction or the Y direction, the minimum size of the wall portion 97 can be made smaller than the minimum size of the compact portion 95. Accordingly, since the porous portion 90 is provided with the sparse portion 94 and the dense portion 95 extending in the Z direction, the resistance to arc discharge and the gas flow rate can be ensured, and the mechanical strength (rigidity) of the porous portion 90 can be improved. .

Moreover, as illustrated in FIG. 5 described later, the size of the plurality of holes 96 provided in each of the plurality of sparse portions 94 can be made smaller than the size of the dense portion 95 in the X direction or the Y direction. According to this, since the size of the plurality of holes 96 can be sufficiently reduced, the resistance to arc discharge can be further improved.

Furthermore, the aspect ratio of the plurality of holes 96 provided in each of the plurality of sparse portions 94 can be 30 or more and 10,000 or less. Accordingly, the resistance to arc discharge can be further improved. More preferably, the lower limit of the 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 size of the plurality of holes 96 provided in each of the plurality of sparse portions 94 can be 1 micrometer or more and 20 micrometers or less. According to this, since the holes 96 extending in one direction with a size of 1 to 20 microns can be arranged, high resistance to arc discharge can be realized.

6(a) and (b) described later, when projected on a plane perpendicular to the Z direction (XY plane), the hole 96a is located in the center of the sparse portion 94, and among the plurality of holes 96 The number of holes 96b to 96g adjacent to and surrounding the hole 96a can be six. Accordingly, in a plan view, a plurality of holes 96 can be arranged with high isotropy and high density. Accordingly, the resistance to arc discharge and the flow rate of the flowing gas can be ensured, and the rigidity of the porous portion 90 can be improved.

Fig. 4 is a schematic plan view illustrating the porous part 90 of the electrostatic chuck according to the embodiment. Fig. 4 shows a part of the porous portion 90 viewed along the Z direction, which corresponds to an enlarged view of Fig. 3(a). When projecting on a plane (XY plane) perpendicular to the Z direction, each of the plurality of sparse portions 94 has a slightly hexagonal shape (slightly regular hexagonal shape). When projected on a plane perpendicular to the Z direction (XY plane), the plural sparse portions 94 have: a sparse portion 94a located at the center of the porous area 91; six sparse portions 94 (sparse portions 94b to 94g) surrounding the sparse portion 94a ).

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

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

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

In addition, each of the length L2 and the length L3 corresponds to the thickness of the compact portion 95. That is, the length L2 is the length along the X direction of the tight portion 95 between the sparse portion 94a and the sparse portion 94b. The length L3 is the length along the X direction of the tight portion 95 between the sparse portion 94a and the sparse portion 94c. The length L2 can be approximately the same as the length L3. For example, the length L2 may be 0.5 times or more and 2.0 times or less the length L3.

Furthermore, the length L1 and the length L4 of the sparse portion 94b along the X direction (the diameter of the sparse portion 94b) can be made substantially the same. The length L1 and the length L5 of the sparse portion 94c along the X direction (the diameter of the sparse portion 95c) can be made substantially the same. For example, each of the length L4 and the length L5 may be 0.5 times or more and 2.0 times or less the length L1.

In this way, the sparse portion 94 a is adjacent to and surrounded by six sparse portions 94 among the plurality of sparse portions 94. That is, when projecting on a plane (XY plane) perpendicular to the Z direction, the number of sparse portions 94 adjacent to one sparse portion 94 in the center of the porous region 91 is six. Accordingly, in plan view, a plurality of sparse portions 94 can be arranged with high isotropy and high density. Accordingly, the resistance to arc discharge and the flow rate of the gas flowing through the through holes 15 can be ensured, and the rigidity of the porous portion 90 can be improved. Furthermore, it is possible to suppress unevenness in resistance to arc discharge, unevenness in the flow rate of the gas flowing through the through holes 15 and unevenness in the rigidity of the porous portion 90.

The diameter (length L1, L4, or L5, etc.) of the sparse portion 94 is, for example, 50 μm or more and 500 μm or less. The thickness (length L2 or L3, etc.) of the tight portion 95 is, for example, 10 μm or more and 100 μm or less. The diameter of the sparse portion 94 is larger 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.

Fig. 5 is a schematic plan view illustrating the porous part 90 of the electrostatic chuck according to the embodiment. FIG. 5 shows a part of the porous part 90 viewed in the Z direction. FIG. 5 is an enlarged view of the periphery of one sparse part 94. As shown in FIG. 5, in this example, the sparse portion 94 has a plurality of holes 96 and a wall portion 97 provided 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 portion 97 has a wall shape that partitions the holes 96 adjacent to each other. As shown in FIG. 5, when projecting on a plane (XY plane) perpendicular to the Z direction, the wall portion 97 is provided so as to surround the outer circumference of each of the plurality of holes 96. The wall portion 97 continues with the dense portion 95 in the outer circumference of the sparse portion 94.

The number of holes 96 provided in one sparse part 94 is, for example, 50 or more and 1000 or less. As shown in FIG. 5, when projected on a plane (XY plane) perpendicular to the Z direction, the plurality of holes 96 have substantially the same size as each other. For example, when projecting on a plane (XY plane) perpendicular to the Z direction, a plurality of holes 96 are uniformly dispersed in the sparse portion 94 isotropically. For example, the distance between adjacent holes 96 (that is, the thickness of the wall 97) is approximately constant.

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

Here, the [capillary structure] of the plurality of holes 96 will be further described. In recent years, circuit line widths and circuit pitches have been reduced for the purpose of increasing semiconductor integration. It is required to apply further high power to the electrostatic chuck to control the temperature of the object W at a higher level. In this context, it is required to reliably suppress arc discharge even in a high-power environment, while ensuring a sufficient gas flow rate and controlling the flow rate with high accuracy. In the electrostatic chuck 110 related to this embodiment, a ceramic plug (porous portion 90) that has been installed conventionally in order to prevent arc discharge in the helium supply hole (gas introduction path 53) is reduced The pore diameter (the diameter of the hole 96) is reduced to a level of, for example, a few μm to several dozen μm (the diameter of the hole 96 will be described in detail later). If the diameter is reduced to this level, it may become difficult to control the flow rate of the gas. Therefore, in the present invention, for example, more effort is made to the shape of the hole 96 so that the hole 96 is along the Z direction. Specifically, in the past, a relatively large hole was used to ensure the flow rate, and the shape was three-dimensionally complicated to prevent arc discharge. On the other hand, in the present invention, the hole 96 is made fine to the level of, for example, a few μm to more than ten μm in diameter to prevent arc discharge, and conversely, the shape is simplified to ensure the flow rate. That is, the present invention was conceived based on a completely different idea from the past.

In addition, the shape of the sparse portion 94 is not limited to a hexagonal shape, and may be a circle (or ellipse) or other polygonal shapes. For example, when projecting on a plane (XY plane) perpendicular to the Z direction, it is assumed that the smallest circle, ellipse, or polygon includes all the holes 96 arranged at intervals of 10 μm or less. The inner side of the circle, ellipse, or polygon can be regarded as the sparse portion 94, and the outer side of the circle, ellipse, or polygon can be regarded as the dense portion 95.

6(a) and (b) are schematic plan views illustrating examples of the porous portion 90 of the electrostatic chuck according to the embodiment. 6(a) and 6(b) show a part of the porous part 90 viewed along the Z direction, and are enlarged views showing the pores 96 in one sparse part 94. As shown in FIG.

As shown in Fig. 6(a), when projected on a plane perpendicular to the Z direction (XY plane), a plurality of holes 96 have: a hole 96a located in the center of the sparse part 94; 6 holes 96 ( Well 96b～96g). The wells 96b to 96g are adjacent to the well 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 aligned with the hole 96a in the X direction. That is, the hole 96a is located between the hole 96b and the hole 96c.

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

In addition, each of the length L7 and the length L8 corresponds to the thickness of the wall portion 97. In other words, the length L7 is the length of the wall 97 between the hole 96a and the hole 96b along the X direction. The length L8 is the length of the wall 97 between the hole 96a and the hole 96c along the X direction. The length L7 can be approximately the same as the length L8. For example, the length L7 can be 0.5 times or more and 2.0 times or less the length L8.

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

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

Here, the method of measuring the diameter of the hole 96 will be described. Use a scanning electron microscope (for example, Hitachi High: Technologies, S-3000) to obtain images with a magnification of more than 1000 times. Using a commercially available image analysis software, the diameter of the circle equivalent to 100 parts of the hole 96 is calculated, and the average value is used as the diameter of the hole 96.

It is more preferable to suppress the unevenness of the diameter of the plurality of holes 96. By reducing the uneven diameter, the flow rate and withstand voltage of the flowing gas can be more precisely controlled. As the unevenness in the diameter of the plurality of holes 96, the cumulative distribution of the diameter corresponding to the circle of 100 obtained in the calculation of the diameter of the hole 96 can be used. Specifically, the concepts of particle size D50 (median size) at a cumulative distribution of 50 vol% and D90 at a cumulative distribution of 90 vol%, which are generally used in particle size distribution measurement, are applied. , Using the cumulative distribution of pores 96 with the horizontal axis as the pore diameter (μm) and the vertical axis as the relative pore volume (%), find the pore diameter (equivalent to D50 diameter) and cumulative distribution when the cumulative distribution of the pore diameter is 50vol% Hole diameter at 90vol% (equivalent to D90 diameter). It is preferable to suppress the unevenness of the diameter of the plurality of holes 96 to a degree that satisfies the relationship of D50:D90≦1:2.

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

In this way, the hole 96 a is adjacent to and surrounded by 6 holes 96 among the plurality of holes 96. That is, when projecting on a plane (XY plane) perpendicular to the Z direction, the number of holes 96 adjacent to one hole 96 in the center portion of the sparse portion 94 is six. Accordingly, in a plan view, a plurality of holes 96 can be arranged with high isotropy and high density. Accordingly, the resistance to arc discharge and the flow rate of the gas flowing through the through holes 15 can be ensured, and the rigidity of the porous portion 90 can be improved. Furthermore, it is possible to suppress unevenness in resistance to arc discharge, unevenness in the flow rate of the gas flowing through the through holes 15 and unevenness in the rigidity of the porous portion 90.

FIG. 6(b) shows another example of the arrangement of a plurality of holes 96 in the sparse portion 94. As shown in FIG. 6(b), in this example, a plurality of holes 96 are arranged concentrically with the hole 96a as the center. According to this, when projecting on a plane (XY plane) perpendicular to the Z direction, a plurality of holes can be arranged with high isotropy and high density.

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

The evaluation of porosity in this specification will be described. Here, the evaluation of the porosity in the porous portion 90 will be described as an example. An image of the top view of FIG. 3(a) is obtained, and the ratio R1 of the plurality of sparse parts 94 in the porous area 91 is calculated by image analysis. The image is obtained using a scanning electron microscope (for example, Hitachi High-Technologies Corporation, S-3000). Acquire BSE images (Backscattered Electron image) with an acceleration voltage of 15kV and a magnification of 30 times. For example, the image size is 1280×960 pixels (pixel), and the image tone is 256 tones.

The ratio R1 of the plurality of sparse parts 94 in the porous area 91 is calculated using image analysis software (for example, Win-ROOFVer6.5 (Mitani Corporation)). The calculation ratio R1 using Win-ROOFVer6.5 can be performed as follows. The evaluation range ROI1 (refer to FIG. 3(a)) is the smallest circle (or ellipse) that includes all the sparse portions 94. A binarization process according to a single threshold value (for example, 0) is performed to calculate the area S1 of the evaluation range ROI1. Binarization processing in accordance with two threshold values (for example, 0 and 136) is performed, and the total area S2 of a plurality of sparse parts 94 in the evaluation range ROI1 is calculated. At this time, the hole filling process in the sparse part 94 and the deletion of a small area considered as noise (threshold value: 0.002 or less) are performed. Moreover, the two thresholds are appropriately adjusted by the brightness or 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)×100.

In the embodiment, the ratio R1 of the plurality of sparse portions 94 in the porous region 91 is, for example, 40% or more and 70% or less, preferably 50% or more and 70% or less. The ratio R1 is, for example, about 60%.

An image of the top view as shown in FIG. 5 is obtained, and the ratio R2 of a plurality of holes 96 in the sparse part 94 is calculated by image analysis. The ratio R2 corresponds to the porosity of the sparse portion 94, for example. The image is obtained using a scanning electron microscope (for example, Hitachi High-Technologies Corporation, S-3000). The acceleration voltage is 15kV and the magnification is 600 times to obtain BSE images. For example, the image size is 1280×960 pixels, and the image tone is 256 tones.

The ratio R2 of the sparse part 94 of the plurality of wells 96 is calculated by using image analysis software (for example, Win-ROOFVer6.5 (Mitani Corporation)). The calculation ratio R1 using Win-ROOFVer6.5 can be performed as follows. The evaluation range ROI2 (refer to FIG. 5) is approximately hexagonal in the shape of the sparse portion 94. All the wells 96 provided in one sparse part 94 are included in the evaluation range ROI2. The binarization process in accordance with a single threshold value (for example, 0) is performed to calculate the area S3 of the evaluation range ROI2. Binarization processing in accordance with two threshold values (for example, 0 and 96) is performed, and the total area S4 of a plurality of holes 96 in the evaluation range ROI2 is calculated. At this time, the filling process in the hole 96 and the deletion of a small area considered as noise (threshold value: 1 or less) are performed. Moreover, the two thresholds are appropriately adjusted by the brightness or 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 sparse portion 94) of the sparse portion 94 of the plurality of pores 96 is, for example, 20% or more and 60% or less, preferably 30% or more and 50% or less. The ratio R2 is, for example, about 40%.

The porosity of the porous region 91 corresponds to, for example, the product of the ratio R1 occupied by the plurality of sparse portions 94 in the porous region 91 and the ratio R2 occupied by the plurality of pores 96 in the sparse portion 94. 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 flow rate of the gas flowing through the through holes 15 can be ensured, and the withstand voltage can be improved.

Similarly, the porosity of the ceramic dielectric substrate 11 and the porous portion 70 can be calculated. In addition, the magnification of the scanning electron microscope is preferably selected appropriately in the range of, for example, several tens of times to several thousands of times in accordance with the observation object.

Figs. 7(a) and (b) are schematic diagrams illustrating examples of porous portions 90 related to other embodiments. Fig. 7(a) is a plan view of the porous portion 90 viewed along the Z direction, and Fig. 7(b) corresponds to an enlarged view of a part of Fig. 7(a). As shown in FIGS. 7(a) and 7(b), in this example, the planar shape of the sparse portion 94 is a circle. In this way, the planar shape of the sparse portion 94 may not be hexagonal.

Fig. 8 is a schematic sectional view illustrating an electrostatic chuck related to the embodiment. FIG. 8 corresponds to an enlarged view of the area B shown in FIG. 2. That is, FIG. 8 shows the vicinity of the interface F1 between the porous portion 90 (the dense region 93) and the ceramic dielectric substrate 11. In addition, in this example, alumina is used as the material of the porous portion 90 and the ceramic dielectric substrate 11.

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

The first region 90p is located between the second region 90q and the ceramic dielectric substrate 11 in the X direction or the Y direction. The first region 90p is a region about 40 to 60 μm from the interface F1 in the X direction or the Y direction. That is, the width W1 of the first region 90p along the X direction or the 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 or less.

Furthermore, the ceramic dielectric substrate 11 has: a first substrate region 11p located on the side of the porous portion 90 (first region 90p) in the X direction or the Y direction; and continues with the first substrate region 11p in the X direction or Y direction The second substrate area 11q. The first region 90p is provided in contact with the first substrate region 11p. The first substrate region 11p is located between the second substrate region 11q and the porous portion 90 in the X direction or the Y direction. The first substrate region 11p is a region that is about 40 to 60 μm from the interface F1 in the X direction or the Y direction. That is, the width W2 of the first substrate region 11p along the X direction or the 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 and 60 μm or less.

Figures 9(a) and (b) are schematic cross-sectional views illustrating an electrostatic chuck related to the embodiment. Fig. 9(a) is an enlarged view of a part of the first region 90p shown in Fig. 8. Fig. 9(b) is an enlarged view of a part of the first substrate region 11p shown in Fig. 8. As shown in FIG. 9(a), the first region 90p includes a plurality of particles g1 (crystal grains). Furthermore, as shown in FIG. 9(b), the first substrate region 11p includes a plurality of particles g2 (crystal grains).

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

Since the average particle size in the first region 90p is different from the average particle size in the first substrate region 11p, the bonding strength between the crystal grains of the porous portion 90 and the crystal grains of the ceramic dielectric substrate 11 can be improved at the interface F1 (Interface strength). For example, peeling of the porous portion 90 from the ceramic dielectric substrate 11 and/or degranulation of crystal grains can be suppressed.

In addition, the average particle diameter can use the average value of the diameter equivalent to the circle of the crystal grains in the image of the cross section of FIG. 9(a) and FIG. 9(b). The diameter equivalent to a circle refers to the diameter of a circle having the same area as the area of the target planar shape.

The ceramic dielectric substrate 11 and the porous portion 90 are also preferably integrated. The porous portion 90 is fixed to the ceramic dielectric substrate 11 by being integrated with the ceramic dielectric substrate 11. According to this, compared with the case where the porous portion 90 is fixed to the ceramic dielectric substrate 11 by an adhesive or the like, the strength of the electrostatic chuck can be improved. For example, it is possible to suppress the deterioration of the electrostatic chuck due to corrosion or erosion of the adhesive.

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. Due to the small particle size in the first substrate region 11p, 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. Moreover, the small particle size in the first substrate region can increase the strength of the ceramic dielectric substrate 11, and can suppress the risk of cracks due to stress generated during production or during the process. For example, the average particle size in the first region 90p is 3 μm or more and 5 μm or less. For example, the average particle size in the first substrate region 11p is 0.5 μm or more and 2 μm or less. The average particle diameter in the first substrate region 11p is 1.1 times or more and 5 times or less the average particle diameter in the first region 90p.

Furthermore, for example, the average particle diameter in the first substrate region 11p is smaller than the average particle diameter in the second substrate region 11q. In the first substrate region 11p provided in contact with the first region 90p, it is better to increase the strength of the interface with the first region 90p by interaction with the first region 90p such as diffusion. On the other hand, in the second substrate region 11q, the original characteristics of the material of the ceramic dielectric substrate 11 are better. By making the average particle diameter in the first substrate region 11p smaller than the average particle diameter in the second substrate region 11q, the interface strength in the first substrate region 11p can be ensured with the ceramic dielectric in the second substrate region 11q. The characteristics of the substrate 11 coexist.

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 11, the bonding strength of the porous portion 90 and the ceramic dielectric substrate can be improved. In addition, since the average particle diameter in the first region 90p is small, the strength of the porous portion 90 is increased, so that the falling of particles during the manufacturing process can be suppressed, and the particles can be reduced.

In addition, as described above, the average particle diameter in the first region 90p may be smaller than the average particle diameter in the second substrate region 11q. According to this, the mechanical strength in the first region 90p can be improved.

The description of the structure of the electrostatic chuck 110 will continue with reference to FIG. 2(a) again. The electrostatic chuck 110 may further have the porous part 70 (the first porous part and the second porous part) as described above. The porous part 70 does not have the plurality of sparse portions 94 and the plurality of dense portions 95 described in FIGS. 3 to 7. In this example, the porous part 70 is provided on the bottom plate, and is arranged opposite to the gas introduction passage 53. The porous part 70 may be provided between the porous part 90 and the gas introduction passage 53 in the Z direction, for example. For example, the porous part 70 is embedded in the ceramic dielectric substrate 11 side of the bottom plate 50. As shown in FIG. 2(a), for example, a counterbore portion 53a is provided on the ceramic dielectric substrate 11 side of the bottom plate 50. The bore 53a is arranged in a cylindrical shape. By appropriately designing the inner diameter of the bore 53a, the porous part 70 is fitted into the bore 53a. In addition, as described later, the porous portion 70 may be provided on the ceramic substrate 11.

In this example, the top surface 70U of the porous portion 70 is exposed on the top surface 50U of the bottom plate 50. The top surface 70U of the porous portion 70 faces the bottom surface 90L of the porous portion 90. In this example, a space SP is formed between the top surface 70U of the porous portion 70 and the bottom surface 90L of the porous portion 90. The first porous part may be either the porous part 90 or the porous part 70. The second porous part may be either the porous part 90 or the porous part 70.

The porous portion 70 has a porous region 71 (examples of the first porous region and the second porous region) having a plurality of pores, and a dense region 72 (first dense region, second dense region) that is denser than the porous region 71 Area example). The porous region 71 is arranged in a cylindrical shape (for example, a cylindrical shape), and is fitted in the bore portion 53a. Although the shape of the porous portion 70 is preferably a cylindrical shape, it is not limited to a cylindrical shape. The porous part 70 uses an insulating material. The material of the porous part 70 is, for example, Al ₂ O ₃ or Y ₂ O ₃ , ZrO ₂ , MgO, SiC, AlN, or Si ₃ N ₄ . The material of the porous part 70 may be glass such as SiO ₂ . The material of the porous part 70 may be Al ₂ O ₃ -TiO ₂ or 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 flowing through the gas introduction passage 53 passes through the plurality of holes 71 p of the porous region 71 and is sent to the groove 14 from the through holes 15 provided in the ceramic dielectric substrate 11.

The dense region 72 has, for example, a portion made of a ceramic insulating film. The ceramic insulating film is arranged between the porous area 71 and the gas introduction passage 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 provided 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 and the like can also be used.

The ceramic insulating film can be sprayed, PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition), sol-gel method (sol-gel method), aerosol deposition method ( Aerosol deposition method) and the like are formed on the side surface of the porous part 70. The film 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. The density is measured in accordance with JIS (Japanese Industrial Standard) C 2141 5.4.3.

Once the porous portion 70 is fitted into the bore portion 53 a of the gas introduction passage 53, the ceramic insulating film is in contact with the bottom plate 50. That is, it becomes the porous part 70 which has the porous region 71 and the dense region 73 with high insulation between the through-hole 15 which guides gas, such as He, to the groove 14 and the bottom plate 50 made of metal. By using such a porous part 70, compared with the case where only the porous region 71 is provided in the gas introduction path 53, it is possible to exhibit high insulation.

Furthermore, the plurality of pores 71p provided in the porous part 70 are more three-dimensionally dispersed than the plural pores 96 provided in the porous part 90, so that the ratio of the pores penetrating the Z direction in the porous part 90 can be higher than that of the porous part 70. The proportion of holes penetrating in the Z direction is still more. Since a higher withstand voltage can be obtained by providing the porous portion 70 having a plurality of pores 71p dispersed three-dimensionally, the gas flow can be smoothed, and the occurrence of arc discharge can be effectively suppressed. Furthermore, as shown in FIG. 2(a), by providing a porous portion 90 with a large proportion of holes penetrating the Z direction on the ceramic dielectric substrate 11, for example, even when the plasma density is high, It can more effectively suppress the occurrence of arc discharge.

The average value of a plurality of pores provided in the porous part (the second porous part, porous part 70 in FIG. 2(a)) provided on the bottom plate 50 can be compared to the average value provided in the ceramic dielectric The average value of the plurality of pores in the porous part of the substrate 11 (the first porous part, which is the porous part 90 in FIG. 2(a)) is still large. According to this, since the porous part with a large hole diameter is provided on the side of the gas introduction passage 53, it is possible to smooth the flow of gas. Furthermore, since the porous part with a small hole diameter is provided on the side of the object to be adsorbed, the occurrence of arc discharge can be suppressed more effectively. Furthermore, in an example in which the porous portion 70 is provided on the bottom plate 50 and the porous portion 90 is provided on the ceramic dielectric substrate 11, the average diameter of the plurality of holes 71p provided in the porous portion 70 can be made to be higher than The average value of the diameters of the plurality of holes 96 of the mass portion 90 is still large. According to this, since the porous portion 70 with a large hole diameter is provided, it is possible to smooth the flow of gas. Furthermore, since the porous portion 90 with a small hole diameter is arranged on the side of the object to be adsorbed, the occurrence of arc discharge can be suppressed more effectively. Furthermore, since the unevenness in the diameter of the plurality of holes can be reduced, more effective suppression of arc discharge can be achieved.

Fig. 10 is a schematic cross-sectional view illustrating the porous part 70 of the electrostatic chuck according to the embodiment. FIG. 10 is an enlarged view of a part of the cross section of the porous region 71. The plurality of holes 71p provided in the porous region 71 are three-dimensionally dispersed in the X direction, the Y direction, and the Z direction in the inside of the porous region 71. In other words, the porous region 71 is a three-dimensional network structure in which the holes 71p expand in the X direction, the Y direction, and the Z direction. In the porous portion 70, a plurality of pores 71p are randomly or uniformly dispersed in the porous region 71, for example.

Since the plurality of holes 71p are three-dimensionally dispersed, part of the plurality of holes 71p is also exposed on the surface of the porous region 71. Therefore, fine irregularities are formed on the surface of the porous region 71. That is, the surface of the porous region 71 can be roughened. Due to the surface roughness of the porous area 71, a ceramic insulating film (dense area 72) can be easily formed on the surface of the porous area 71, for example. For example, the contact between the ceramic insulating film (the dense region 72) and the porous region 71 is improved. Furthermore, peeling of the ceramic insulating film (dense region 72) can be suppressed.

The average value of the diameters of the plurality of holes 71p provided in the porous region 71 is larger than the average value of the diameters of the plurality of holes 96 provided in the porous region 91, for example. The diameter of the hole 71p is, for example, 10 μm or more and 50 μm or less. With the porous region 91 having the small diameter of the hole 96, the flow rate of the gas flowing through the through hole 15 can be controlled (restricted). According to this, it is possible to suppress the unevenness of the gas flow rate caused by the porous region 71. The measurement of the diameter of the hole 71p and the diameter of the hole 96 can be performed by a scanning electron microscope as described above.

Fig. 11 is a schematic cross-sectional view illustrating a porous portion 90 related to another embodiment. Fig. 11 illustrates the periphery of the porous portion 90 as in Fig. 2(a). In this example, the porous part 90 is provided on the ceramic dielectric substrate 11. The porous part 70 is provided on the bottom plate 50. That is, the porous part 90 is used as the first porous part. The porous part 70 is used as the second porous part. In addition, the porous portion 90 may be provided on both the ceramic dielectric substrate 11 and the bottom plate 50.

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

The bonding member 61 uses, for example, a silicon adhesive. The next member 61 is, for example, an elastic member having elasticity. The elastic modulus (elastic modulus) of the member 61 is 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, for example.

In the structure in which the porous portion 90 and the ceramic dielectric substrate 11 are bonded by the bonding member 61, the bonding member 61 can be used as a buffer for the difference between the thermal contraction of the porous portion 90 and the thermal contraction of the ceramic dielectric substrate 11. material.

Figs. 12(a) and (b) are schematic cross-sectional views illustrating examples of porous portions 90 related to other embodiments. In the aforementioned 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 bottom plate 50. However, when the porous portion 90 is used, either the porous portion provided on the bottom plate 50 or the porous portion provided on the ceramic dielectric substrate 11 may be omitted. For example, in the example shown in FIG. 12(a), the porous portion 90 is provided on the ceramic dielectric substrate 11, and the gas introduction path 53 is provided on the bottom plate 50. Accordingly, the flow path resistance of the gas such as He supplied to the porous portion 90 can be reduced.

Furthermore, in the example shown in FIG. 12( b ), the ceramic dielectric substrate 11 is provided with a hole 15 b, and the porous section 90 is provided on the bottom plate 50. Accordingly, the flow path resistance of the gas such as He supplied to the porous portion 90 can be reduced.

Furthermore, 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 line. For example, so-called [R face chamfering] may be applied to the edge 53b of the opening of the gas introduction passage 53. In this case, the edge 53b of the opening of the gas introduction passage 53 may be formed with a curve with a radius of about 0.2 millimeters (mm). As described above, the bottom plate 50 is formed of metal such as aluminum. Therefore, if the edge of the opening of the gas introduction channel 53 is sharp, electric field concentration is likely to occur, and arc discharge may easily occur.

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

Figs. 13(a) to (d) are schematic cross-sectional views illustrating examples of porous portions 90a and 70a related to other embodiments. 14(a) to (c) are schematic cross-sectional views illustrating examples of porous portions 90a and 90b related to other embodiments. Fig. 13(a) is a case where a porous portion 90a with a modified dense region 93 of the porous portion 90 is provided on the ceramic dielectric substrate 11, and a porous portion 70a with a modified dense region 72 of the porous portion 70 is provided on the bottom plate 50 example. Fig. 14(a) is a case where a porous portion 90a with a modified dense region 93 of the porous portion 90 and a porous portion 70b with a modified dense region 72 of the porous portion 70 are provided on the ceramic dielectric substrate 11 and the bottom plate 50, respectively example. As shown in FIG. 13(a), FIG. 13(b), and FIG. 14(a), in the porous portion 90a provided on the ceramic dielectric substrate 11, the porous region 91 further has a dense portion 92a. That is, the porous part 90a is a part where the dense part 92a is added to the aforementioned porous part 90.

As shown in FIGS. 13(a) and 13(b), the dense portion 92a can be formed in a plate shape (for example, a disc shape). As shown in FIG. 14(a), the dense portion 92a can also be formed in a columnar shape (for example, a columnar shape). The material of the dense portion 92a may be the same as the material of the aforementioned dense region 93, for example. The dense portion 92 a is denser than the porous region 91. The density of the dense portion 92a and the dense region 93 may be the same degree. When projected on a plane (XY plane) perpendicular to the Z direction, the dense portion 92a overlaps the hole portion 15b. The porous region 91 and the hole 15b do not overlap and are more preferably configured. According to this configuration, the generated current flows in the dense portion 92a in a detour. Therefore, since the distance (conduction path) through which the current flows can be lengthened, electrons are difficult to be accelerated, and the occurrence of arc discharge can be suppressed.

Moreover, when projecting 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 preferably larger than the size of the hole 15b. According to this, the current flowing inside the hole 15b can be guided to the dense portion 92a. Therefore, it is possible to effectively lengthen the distance through which the current flows (the conductive path).

In this example, when projecting on a plane (XY plane) perpendicular to the Z direction, a porous region 91 is provided around the dense portion 92a. Since the dense portion 92a is arranged at a position opposed to the hole portion 15b to improve resistance to arc discharge, and at the same time, the surrounding area is regarded as the porous area 91, so that sufficient air flow can be ensured. In other words, the reduction of arc discharge and the smoothing of the gas flow can coexist.

As shown in Fig. 13(a), the length of the dense part 92a along the Z direction may be smaller than the length of the porous part 90a along the Z direction. As shown in Fig. 14(a), it may be combined with the porous part The length of 90a along the Z direction is approximately the same. If the length of the dense portion 92a along the Z direction is increased, the occurrence of arc discharge can be suppressed more effectively. If the length of the dense portion 92a along the Z direction is smaller than the length of the porous portion 90a along the Z direction, the flow of gas can be smoothed.

The dense portion 92a may be composed of a dense body having substantially no pores, and if it is denser than the porous region 91, it may be composed of a plurality of pores. In the case where the dense portion 92a has a plurality of pores, it is better to make the diameter of the pores smaller than the diameter of the pores of the porous region 91. The porosity (percentage: %) of the dense portion 92a can be made lower than the porosity (%) of the porous region 91. Therefore, the density (g/cm³: 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 made the same as the porosity of the aforementioned dense region 93, for example.

Here, arc discharge often occurs when current flows inside the hole 15b from the ceramic dielectric substrate 11 side toward the bottom plate 50 side. Therefore, if the dense portion 92a having a low porosity is arranged near the hole 15b, as shown in Figs. 13(a) and 14(a), the current 200 bypasses the dense portion 92a. Therefore, since the distance (conduction path) through which the current 200 flows can be lengthened, electrons are difficult to be accelerated, and the occurrence of arc discharge can be suppressed.

In addition, as shown in FIG. 13(a), for example, a porous portion 70a having a dense portion 92b in the porous region 71 of the porous portion 70 provided on the bottom plate 50 can be used. Furthermore, as shown in FIG. 14( a ), the porous portion 90 a may be provided on the ceramic dielectric substrate 11 and the porous portion 70 b may be provided on the bottom plate 50. The porous portion 70b is the porous region 71 and further has a dense portion 92b. That is, the porous part 70b is a part where the dense part 92b is further added to the aforementioned porous part 70. That is, the dense part 92b can also be added to the porous part 70 or the porous part 90 provided in the bottom plate 50.

At least one dense portion 92b may be provided. As shown in FIG. 13(c) and FIG. 14(b), a plurality of dense portions 92b having a plate shape (for example, a disc shape) or a column shape (for example, a column shape) can be provided. As shown in FIG. 13(d) and FIG. 14(c), a dense portion 92b having a ring shape (for example, an annular shape) or a cylindrical shape (for example, a cylindrical shape) can be provided. The material, density, porosity, etc. of the dense part 92b can be made the same as the dense part 92a.

When projecting on a plane (XY plane) perpendicular to the Z direction, at least a part of the dense part (for example, dense part 92b) of the porous part provided on the bottom plate 50 and the porous part provided on the ceramic dielectric substrate 11 It is preferable that the dense part (for example, the dense part 92a) which the part has overlapped. According to this configuration, for example, in the porous portion 90a (porous portion on the ceramic dielectric substrate 11 side), the current flowing through the dense portion 92a flows through the porous portions 70, 90b (bottom plate 50) provided with the dense portion 92b. In the case of the side porous part), it does not flow in the porous region (for example, the porous regions 71 and 91) of the porous part provided on the bottom plate 50 side, but flows in a detour to the dense part 92b. Therefore, since the distance (conduction path) through which the current flows can be longer, electrons are more difficult to be accelerated, and the occurrence of arc discharge can be effectively suppressed.

15(a) and (b) are schematic cross-sectional views illustrating examples of porous parts related to other embodiments. As shown in FIGS. 15(a) and (b), when projecting on a plane (XY plane) perpendicular to the Z direction, the dense portion 92a and the dense portion 92b can be overlapped. Moreover, when projecting on a plane (XY plane) perpendicular to the Z direction, the dense portion 92a and the dense portion 92b may be brought into contact. In addition, when projecting on a plane (XY plane) perpendicular to the Z direction, if the gap between the dense portion 92a and the dense portion 92b is small, current can be suppressed from flowing between the dense portion 92a and the dense portion 92b. Therefore, if the current can be suppressed from flowing between the dense portion 92a and the dense portion 92b, a gap can also be provided between the dense portion 92a and the dense portion 92b. Accordingly, it is possible to suppress the current flowing in the porous portion 90a from flowing in the porous portion 70a without passing through the dense portion 92b. Therefore, the distance (conducting path) through which the current flows can be effectively lengthened.

Furthermore, as shown in FIGS. 15(a) and (b), when projecting on a plane (XY plane) perpendicular to the Z direction, it is preferable that the dense portion 92b overlaps the dense region 93. In addition, when projecting on a plane (XY plane) perpendicular to the Z direction, the dense portion 92b may be brought into contact with the dense region 93. According to this, since the distance (conduction path) through which the current flows can be longer, electrons are more difficult to be accelerated, and the occurrence of arc discharge can be effectively suppressed.

Fig. 16 is a schematic cross-sectional view illustrating an electrostatic chuck related to another embodiment. Figs. 17(a) and (b) correspond to enlarged views of the area C shown in Fig. 16. As shown in FIGS. 16 and 17(a) and (b), the electrostatic chuck 110a includes a ceramic dielectric substrate 11c and a bottom plate 50. That is, no porous part (porous part 70 or porous part 90) is provided in the ceramic dielectric substrate 11c. A plurality of holes 16 are directly provided in the ceramic dielectric substrate 11c. The plurality of holes 16 may 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 surface 14 a 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 in FIGS. 17(a) and (b), a porous part (for example, a porous part 70a) may be provided on the bottom plate 50. In addition, the bottom plate 50 may be provided with a porous portion 90b. Furthermore, as illustrated in FIG. 12( a ), the bottom plate 50 may not be provided with the porous portion 70 or the porous portion 90 and the gas introduction path 53 may be provided.

17(a) and (b), the top surface 70U of the porous portion 70 (or the top surface 90U of the porous portion 90) of the bottom plate 50 and the second main body of the ceramic dielectric substrate 11c are provided The surface 11b does not need to be in contact. Furthermore, as with the foregoing, at least a part of the edge 53b of the opening on the ceramic dielectric substrate 11c side of the gas introduction channel 53 can be formed in a curved line.

If a plurality of holes 16 are provided in the ceramic dielectric substrate 11c, the flow rate of the gas supplied between the back surface of the object W placed on the electrostatic chuck 110a and the first main surface 11a including the groove 14 can be ensured, and at the same time Can improve the resistance to arc discharge.

The length along the Z direction of the dense portion 92b can be made smaller than the length along the Z direction of the porous portions 70a and 90b. In addition, the length of the dense portion 92b along the Z direction may be approximately the same as the length of the porous portions 70a and 90b along the Z direction. If the length of the dense portion 92b along the Z direction is shortened, the air flow can be smoothed. If the length of the dense portion 92b along the Z direction is increased, the occurrence of arc discharge can be more effectively suppressed.

When projecting on a plane (XY plane) perpendicular to the Z direction, at least one of the plurality of holes 16 can be overlapped with 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. 17(a), the porous portion 70a having a plurality of dense portions 92b may be provided on the bottom plate 50. As shown in FIG. 17(b), the porous portion 90b having a plurality of dense portions 92b may be provided on the bottom plate 50.

Fig. 18 is a schematic cross-sectional view illustrating a plurality of holes 16h related to another embodiment. The plurality of holes 16h can be formed in the ceramic dielectric substrate 11 by laser irradiation, ultrasonic processing, or the like. As shown in FIG. 18, at least one of the plurality of holes 16h provided in the ceramic dielectric substrate 11 may have a first portion 16h1 opening in the groove 14 and a second portion 16h2 opening in the second main surface 11b. In the X direction or the Y direction, the size of the first portion 16h1 can be made smaller than the size of the second portion 16h2. In the X direction or the Y direction, the opening size D4 of at least one of the plurality of holes 16h on the surface 14a side of the groove 14 can be made smaller than the opening size D3 on the bottom plate 50 side. In addition, although the hole 16h having a stepped structure is illustrated in FIG. 18, the hole 16h having a taper structure may also be used. For example, the opening size D4 can also be 0.01 millimeters (mm) to 0.1 millimeters (mm) in diameter. For example, the opening size D3 can also be about 0.15 millimeters (mm) to 0.2 millimeters (mm) in diameter. If the opening size D4 is smaller than the opening size D3, the occurrence of arc discharge can be effectively suppressed. Moreover, the aspect ratio of the hole 16h can also be 3-60, for example. In the calculation of the aspect ratio, [vertical] is, for example, the length of the hole 16h in the Z direction in FIG. 18, and [horizontal] is the X-direction length of the hole 16h on the top surface (face 14a) of the hole 16h and the bottom surface of the hole 16h (2nd main surface 11b) The average length of the length of the X direction of the hole 16h. In addition, the length of the hole 16h in the X direction can be measured using an optical microscope such as a laser microscope, a factory microscope, or a digital microscope. Furthermore, the opening size D4 can be made smaller than the length L1 of the sparse part 94a illustrated in FIG. 4 (the length L4 of the sparse part 94b, the length L5 of the sparse part 94c).

19(a) and (b) 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 area D shown in FIG. 19(a). In FIG. 19(a), there is no part of the opening size 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. As shown in Figure 19 (a) and (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) can be made larger than the opening on the second main surface 11b side of the hole 16 The edge 16j also slopes gently. In this example, at least one of the plurality of holes 16 has an angle formed by the edge 16i of the opening on the side of the groove 14 of the hole 16 and the surface 14a on the side of the second main surface 11b of the groove 14 as α. When the angle between the edge 16j of the opening on the second main surface 11b side and the second main surface 11b is β, it becomes [α<β]. According to this, the concentration of the electric field can be suppressed, and the arc discharge can be reduced. In addition, in this example, the edge 16i is formed with a straight line. However, the edge 16i can be composed of a curve, or a straight line and a curve. In the case where the edge 16i and the edge 16j are formed by curves, the radius of curvature of the edge 16i can be made larger than the radius of curvature of the edge 16j. In the case where the edge 16i and the edge 16j are composed of straight lines and curved lines, at least any one of the relationship between the linear portions and the relationship between the curved portions may satisfy the aforementioned relationship.

If the edge 16i is more gently inclined than the edge 16j, the occurrence of inclination and the like and electric field concentration can be suppressed. Therefore, the occurrence of arc discharge can be suppressed more effectively. In addition, as an example, although the shape of the opening portion of the hole 16 has been exemplified, the same is true for the hole 16h having a stepped structure or a push-out structure.

Fig. 20 is a schematic cross-sectional view illustrating an electrostatic chuck related to another embodiment. FIG. 20 is equivalent to an enlarged view of the area C shown in FIG. 16. Each of the plurality of holes 16 illustrated in FIG. 17(a) extends substantially in the Z direction. In contrast, at least one of the plurality of holes 16 illustrated in FIG. 20 can also be configured to be inclined to the Z direction. If at least one of the plurality of holes 16 extends in a direction inclined to the Z direction, it can be considered that electrons are difficult to be accelerated when current flows inside the hole 16. Therefore, the occurrence of arc discharge can be effectively suppressed. According to the knowledge obtained by the inventors, if the angle θ inclined to the Z direction is 5° or more and 30° or less, preferably 5° or more and 15° or less, the arc can be suppressed without reducing the diameter of the hole 16 The occurrence of discharge.

In addition, as an example, although the case of the hole 16 was illustrated, the case of the hole 16h having a stepped structure or a push-out structure is the same.

The hole 16 inclined to the Z direction can be directly formed in the ceramic dielectric substrate 11c by laser irradiation, ultrasonic processing, or the like. Therefore, the area provided with at least one hole 16 inclined to the Z direction contains the same material as the ceramic dielectric substrate 11.

Fig. 21 is a schematic cross-sectional view illustrating an electrostatic chuck related to another embodiment. FIG. 21 is equivalent to an enlarged view of the area C shown in FIG. 16. As shown in FIG. 21, the porous portion 90b is the porous region 91 further having a dense portion 92b. That is, the porous part 90b is a part where the dense part 92b is added to the aforementioned porous part 90. That is, the dense portion 92b may be further added to the porous portion 70 or the porous portion 90 provided on the bottom plate 50. When projecting 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.

Fig. 22 is a schematic cross-sectional view illustrating an electrostatic chuck related to another embodiment. FIG. 23 is equivalent to an enlarged view of the area E shown in FIG. 22. Fig. 24 is an enlarged view showing another embodiment of the area E shown in Fig. 22. As shown in FIGS. 22, 23, and 24, the electrostatic chuck 110b includes a ceramic dielectric substrate 11d and a bottom 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 provided 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 surface 14 a 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 through the ceramic dielectric substrate 11d in the Z direction.

As shown in FIG. 23, when projecting on a plane (XY plane) perpendicular to the Z direction, at least one of the plurality of holes 16 can be overlapped with the dense portion 92b. The material, density, porosity, etc. of the dense portion 92b are as described above, for example. As shown in FIG. 24, when projecting on a plane (XY plane) perpendicular to the Z direction, at least one of the plurality of holes 16 can be overlapped with the dense portion 92a. The material, density, porosity, etc. of the dense portion 92a are as described above, for example.

(Processing device) FIG. 25 is a schematic diagram illustrating a processing device 200 related to the embodiment of the present invention. As shown in FIG. 25, an electrostatic chuck 110, a power supply 210, a medium supply unit 220, and a supply unit 230 can be arranged in the processing device 200. The power supply 210 is electrically connected to the electrode 12 provided on the electrostatic chuck 110. The power supply 210 can be a DC power supply, for example. The power supply 210 applies a predetermined voltage to the electrode 12. Furthermore, the power supply 210 may be provided with a switch for switching the application of the voltage and stopping the application of the voltage.

The medium supply unit 220 is connected to the input channel 51 and the output channel 52. The medium supply unit 220 may be configured to supply a liquid as a cooling medium or a heat-retaining medium, for example. The medium supply unit 220 has, for example, a storage unit 221, a control valve 222, and a discharge unit 223.

The accommodating part 221 can be, for example, a tank for accommodating a liquid or factory piping. In addition, a cooling device or a heating device that controls the temperature of the liquid may be installed in the storage portion 221. The accommodating part 221 can also be equipped with a pump etc. for sending a liquid.

The control valve 222 is connected between the input passage 51 and the receiving portion 221. The control valve 222 can control at least any one of the flow rate and pressure of the liquid. Furthermore, the control valve 222 can also be configured to switch the supply and stop of the liquid supply.

The discharge part 223 is connected to the output channel 52. The discharge part 223 can be a tank or a drain pipe for recovering the liquid discharged from the output channel 52. In addition, the discharge part 223 is not necessarily required, and the liquid discharged from the output channel 52 may be supplied to the storage part 221. According to this, since the cooling medium or the heat insulating medium can be circulated, resource saving can be achieved.

The supply unit 230 has a gas supply unit 231 and a gas control unit 232. The gas supply unit 231 can be a high-pressure steel cylinder or factory piping that stores gas such as helium. In addition, although the case where one gas supply unit 231 is provided is described as an example, a plurality of gas supply units 231 may be provided.

The gas control unit 232 is connected between the plurality of gas introduction passages 53 and the gas supply unit 231. The gas control unit 232 can control at least one of the flow rate and pressure of the gas. In addition, the gas control unit 232 can be further configured to switch the supply of gas and stop the supply of gas. The gas control unit 232 can be, for example, a mass flow controller or a mass flow meter.

As shown in FIG. 25, a plurality of gas control units 232 can be provided. For example, the gas control part 232 may be provided for every plural areas of the first main surface 11a. According to this, it is possible to control the gas supplied for each of a plurality of areas. In this case, the gas control unit 232 can also be provided for every plural gas introduction passages 53. According to this, the gas in a plurality of regions can be controlled more precisely. In addition, although the case where a plurality of gas control units 232 are provided is described as an example, if the gas control unit 232 can independently control the supply of gas in a plurality of supply systems, one unit may be sufficient.

Here, the means for holding the object W includes a vacuum chuck or a mechanical chuck. However, the vacuum chuck cannot be used in an environment where the pressure is lower than atmospheric pressure. Furthermore, if a mechanical chuck is used, the object W may be damaged or particles may be generated. Therefore, for example, processing devices used in semiconductor manufacturing processes use electrostatic chucks.

In this processing device, the processing space needs to be isolated from the external environment. Therefore, the processing device 200 may further include a chamber 240. The reaction chamber 240 can also be configured to have an airtight structure capable of maintaining an environment decompressed more than atmospheric pressure, for example. In addition, the processing device 200 may include a plurality of lift pins and a driving device for raising and lowering the plurality of lift pins. When receiving the object W from the conveying device or delivering the object W to the conveying device, the ejector pin is raised by the driving device and protrudes from the first main surface 11a. When the object W received from the conveying device is placed on the first main surface 11 a, the ejector pin is lowered by the driving device and is housed in the ceramic dielectric substrate 11.

Furthermore, the processing device 200 can be provided with various devices corresponding to the content to be processed. For example, a vacuum pump etc. which exhaust the inside of the reaction chamber 240 may be provided. A plasma generator for generating plasma may be provided in the reaction chamber 240. A process gas supply part for supplying process gas may be provided inside the reaction chamber 240. A heater for heating the object W or the process gas may be provided in the reaction chamber 240. In addition, the devices provided in the processing device 200 are not limited to those illustrated. Since a known technology can be applied to the device installed in the processing device 200, a detailed description is omitted.

The foregoing has described the mode of implementation of the present invention. However, the present invention is not limited to these descriptions. For example, although a configuration using Coulomb force (Coulomb force) is exemplified as the electrostatic chuck 110, even a configuration using Johnsen-Rahbek force (Johnsen-Rahbek force) is applicable. In addition, regarding the aforementioned embodiment, those skilled in the art may appropriately add design changes as long as they also have the characteristics of the present invention, and they are included in the scope of the present invention. In addition, the various elements provided in the aforementioned embodiments can be combined as technically as possible, and the combination of these elements is included in the scope of the present invention as long as they also include the features of the present invention.

11c, 11d: ceramic dielectric substrate 11a: First major surface 11b: Second major surface 11p: first substrate area 12: Electrode 13: Point 14: groove 14a: bottom surface 15: Through hole 15a, 15b, 15c, 15d: hole 15c1: surface 15w: inner wall 16, 16h, 96: well 16i, 16j: edge 20: Connection part 50: bottom plate 50a: upper part 50b: lower part 50U, 70U, 90U: top surface 51: input channel 52: output channel 53: Gas inlet 53a: Boring part 53b: Edge 55: Connect Channel 60: Joint 61: Next component 70, 90, 90a, 90b: porous part 70a: Porous part 71: porous area 72, 93: dense area 90p: first area 90q: second area 90L: bottom surface 91: porous area 91s, 93s: side 92a, 92b: dense part 94, 94a~94g, 95c: sparse part 95: tight part 96, 96a~96g: well 97: Wall 110, 110a: Electrostatic chuck 200: processing device 210: Power 211: Wiring 220: Media Supply Department 221: Containment Department 222: control valve 223: discharge part 230: Supply Department 231: Gas Supply Department 232: Gas Control Department A, B, C, D, E: area F1: Interface L0~L11: length ROI1: Evaluation scope ROI2: Evaluation scope SP: Space W: Object W1, W2: width

Fig. 1 is a schematic cross-sectional view illustrating an electrostatic chuck related to this embodiment. 2(a)~(d) are schematic diagrams illustrating the electrostatic chuck related to the embodiment. 3(a) and (b) are schematic diagrams illustrating the porous part of the electrostatic chuck related to the embodiment. Fig. 4 is a schematic plan view illustrating the porous part of the electrostatic chuck according to the embodiment. Fig. 5 is a schematic plan view illustrating the porous part of the electrostatic chuck according to the embodiment. Fig. 6 (a) and (b) are schematic plan views illustrating examples of the porous part of the electrostatic chuck related to the embodiment. Fig. 7 (a) and (b) are schematic diagrams illustrating the first porous part related to other embodiments. Fig. 8 is a schematic sectional view illustrating an electrostatic chuck related to the embodiment. Figures 9(a) and (b) are schematic cross-sectional views illustrating an electrostatic chuck related to the embodiment. Fig. 10 is a schematic cross-sectional view illustrating the porous part of the electrostatic chuck according to the embodiment. Fig. 11 is a schematic cross-sectional view illustrating a porous part related to another embodiment. Figs. 12(a) and (b) are schematic cross-sectional views illustrating examples of porous parts related to other embodiments. Fig. 13 (a) to (d) are schematic cross-sectional views illustrating examples of porous parts related to other embodiments. 14(a) to (c) are schematic cross-sectional views illustrating examples of porous parts related to other embodiments. 15(a) and (b) are schematic cross-sectional views illustrating examples of porous parts related to other embodiments. Fig. 16 is a schematic cross-sectional view illustrating an electrostatic chuck related to another embodiment. 17(a) and (b) are enlarged views of the area C shown in FIG. 16. Fig. 18 is a schematic cross-sectional view illustrating a plurality of holes related to another embodiment. 19(a) and (b) are schematic cross-sectional views illustrating the shape of the opening portion of the hole. Fig. 20 is a schematic cross-sectional view illustrating an electrostatic chuck related to another embodiment. Fig. 21 is a schematic cross-sectional view illustrating an electrostatic chuck related to another embodiment. Fig. 22 is a schematic cross-sectional view illustrating an electrostatic chuck related to another embodiment. Fig. 23 is an enlarged view of the area E shown in Fig. 22. Fig. 24 is an enlarged view showing another embodiment of the area E shown in Fig. 22. Fig. 25 is a schematic diagram illustrating a processing device related to the embodiment of the present invention.

11: Ceramic dielectric substrate

11a: First major surface

11b: Second major surface

12: Electrode

13: Point

14: groove

14a: bottom surface

15: Through hole

15a, 15b, 15c: hole

15w: inner wall

50U, 70U, 90U: top surface

53: Gas inlet

53a: Boring part

53b: Edge

60: Joint

90a: Porous part

70a: Porous part

71: porous area

72, 93: dense area

90L: bottom surface

91: porous area

91s, 93s: side

92a, 92b: dense part

200: processing device

SP: Space

W: Object

Claims (16)

An electrostatic chuck, characterized in that it contains: The ceramic dielectric substrate has: a first main surface on which the object to be adsorbed is placed, and a second main surface opposite to the first main surface; The bottom plate supports the ceramic dielectric substrate and has a gas introduction channel; The first porous part is arranged on the ceramic dielectric substrate and is opposite to the gas introduction channel; and The second porous part is arranged on the bottom plate and is opposite to the gas introduction channel, The ceramic dielectric substrate has a first hole portion located between the first main surface and the first porous portion, The first porous part has: a first porous region having a plurality of pores, and a first dense region denser than the first porous region, and the first porous region further has at least one first dense part , The second porous part has: a second porous region having a plurality of pores, and a second dense region denser than the second porous region, and the second porous region further has at least one second dense part , When projected on a plane perpendicular to the first direction from the bottom plate to the ceramic dielectric substrate, the first dense part overlaps the first hole part, and at least a part of the second dense part is overlapped with the first dense part At least a part of overlaps, or at least a part of the second dense part is in contact with at least part of the first dense part. Such as the electrostatic chuck of claim 1, wherein when projected on a plane perpendicular to the first direction, the size of the first dense portion is the same as the size of the first hole, or the size of the first dense portion is larger than the size of the first hole The size of a hole. Such as the electrostatic chuck of claim 1 or claim 2, wherein when projected on a plane perpendicular to the first direction, the second dense part overlaps the first dense region, or the second dense part overlaps the first dense region Areas meet. For example, the electrostatic chuck of claim 1 or claim 2, wherein the first porous area has a plurality of first loose parts and first tight parts, The first sparse part has the plurality of holes, The first dense portion has a density higher than the density of the first sparse portion, and the size in the second direction is smaller than the size of the first dense area in the second direction, Each of the plurality of first sparse parts extends in the first direction, The first tight part is located between the plurality of first sparse parts, The first sparse portion has a first wall portion arranged between the plurality of holes, In a second direction that is slightly orthogonal to the first direction, the minimum value of the size of the first wall portion is smaller than the minimum value of the size of the first compact portion. For example, the electrostatic chuck of claim 1 or claim 2, wherein in the second direction, the size of the plurality of holes provided in each of the plurality of first sparse portions is smaller than the size of the first compact portion, and /Or in the second direction, the size of the plurality of holes provided in each of the plurality of second sparse portions is smaller than the size of the second dense portion. For example, the electrostatic chuck of claim 1 or claim 2, wherein the aspect ratio of the plurality of holes provided in each of the plurality of first sparse parts, and/or the plurality of holes provided in each of the plurality of second sparse parts The aspect ratio of each hole is 30 or more. For example, the electrostatic chuck of claim 1 or claim 2, wherein in the second direction, the size of the plurality of holes arranged in each of the plurality of first sparse parts, and/or the size of the plurality of holes arranged in the plurality of second sparse parts The size of each of the plurality of holes is 1 micrometer or more and 20 micrometers or less. For example, the electrostatic chuck of claim 1 or claim 2, wherein when viewed along the first direction, the plurality of holes provided in the first sparse part includes a first hole located at the center of the first sparse part, Among the plurality of holes, the number of holes adjacent to and surrounding the first hole is 6, and/or When viewed along the first direction, the plurality of holes provided in the second sparse part includes a second hole located at the center of the second sparse part, The number of holes adjacent to and surrounding the second hole among the plurality of holes is 6. Such as the electrostatic chuck of claim 1 or claim 2, wherein the length of the first dense part along the first direction is smaller than the length of the first porous part along the first direction. For example, the electrostatic chuck of claim 1 or claim 2, wherein in the first direction, the first porous area is provided between the first dense portion and the bottom plate. Such as the electrostatic chuck of claim 1 or claim 2, wherein the length of the first dense part along the first direction is substantially the same as the length of the first porous part along the first direction. For example, the electrostatic chuck of claim 1 or claim 2, wherein when projected on a plane perpendicular to the first direction, the plurality of first sparse parts are arranged around the first dense part. For example, the electrostatic chuck of claim 1 or claim 2, wherein the average diameter of the plurality of holes provided in the second porous part is greater than the average diameter of the plurality of holes provided in the first porous part The value is still great. For example, the electrostatic chuck of claim 1 or claim 2, wherein at least a part of the edge of the opening on the ceramic dielectric substrate side of the gas introduction channel is formed by a curve. The electrostatic chuck of claim 1 or claim 2, wherein the ceramic dielectric substrate has a first hole located between the first main surface and the first porous portion, At least any one of the ceramic dielectric substrate and the first porous portion has a second hole portion located between the first hole portion and the first porous portion, In a second direction that is slightly orthogonal to the first direction, the size of the second hole is smaller than the size of the first porous portion and larger than the size of the first hole. A processing device, characterized by comprising: The electrostatic chuck of any one of Claim 1 to Claim 15; and The supply unit can supply gas to the gas introduction path provided in the electrostatic chuck.

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