JP7503242B2 - Electrostatic Chuck - Google Patents

Description

An aspect of the present invention relates to an electrostatic chuck.

An electrostatic chuck has a ceramic dielectric substrate made of, for example, alumina, and an electrode provided inside the ceramic dielectric substrate. When power is applied to the electrode, an electrostatic force is generated. An electrostatic chuck uses the generated electrostatic force to attract an object such as a silicon wafer. In such an electrostatic chuck, an inert gas such as helium (He) (hereinafter simply referred to as gas) is flowed between the front surface of the ceramic dielectric substrate and the back surface of the object to control the temperature of the object.

For example, in devices that process substrates, such as CVD (Chemical Vapor Deposition) devices, sputtering devices, ion implantation devices, and etching devices, the temperature of the substrate may rise during processing. For this reason, in electrostatic chucks used in such devices, gas is passed between the ceramic dielectric substrate and the substrate, and the substrate is brought into contact with the gas in order to dissipate heat from the substrate.

During processing, a temperature distribution occurs within the surface of the object. In this case, if the gas pressure is increased, the amount of heat dissipated from the object increases, and the temperature of the object can be reduced. For this reason, the surface of the ceramic dielectric substrate facing the object is divided into multiple regions, and the gas pressure in the multiple regions is changed to control the temperature within the surface of the object.

For example, a technique has been proposed in which a seal ring is provided between each region in order to control the gas pressure in each region (see, for example, Patent Document 1).
In this case, in order to control the gas pressure in each region, it is preferable to hermetically separate each region with a seal ring. However, doing so makes it possible for particles generated during the wafer processing process to easily accumulate in the seal ring, which may cause problems such as defects in that region.

A technique has also been proposed in which a small gap is provided between the top of the seal ring and the object, and the gas pressure in each region is controlled (see Patent Document 2).
Even in this case, the problem of particles easily accumulating in the seal ring portion has not been solved.
Therefore, there has been a demand for the development of a technique that can effectively control the gas pressure in each region while suppressing the accumulation of particles in the seal ring portion.

JP 2011-119708 A JP 2012-129547 A

The present invention was made based on the recognition of such problems, and aims to provide an electrostatic chuck that can effectively control the gas pressure in each region while suppressing the accumulation of particles in the seal ring portion.

A first invention comprises a base plate and a ceramic dielectric substrate provided on the base plate and having a first main surface exposed to the outside, the first main surface including a plurality of dots on which an object can be placed, at least a first region (region 101), a second region (region 102) located outside the first region and adjacent to the first region, and a fourth region located inside the first region and adjacent to the first region, the first region of the first main surface including a plurality of first grooves (grooves 14a, 14b) and at least one of the plurality of first grooves. and at least one first gas introduction hole (gas introduction hole 15) connected to one of the first main surface, the plurality of first grooves include a first boundary groove (groove 14a) provided closest to a first boundary (boundary 102a) between the first region and the second region and extending along the first boundary , a fourth boundary groove provided closest to a fourth boundary between the first region and the fourth region and extending along the fourth boundary, and at least one first region intra-groove (groove 14b) different from the first boundary groove and the fourth boundary groove , In the second region, a plurality of second grooves (grooves 14a, 14b) and at least one second gas introduction hole (gas introduction hole 15) connected to at least one of the plurality of second grooves are provided, the plurality of second grooves include a second boundary groove (groove 14a) that is provided closest to the first boundary and extends along the first boundary, and the gas supplied to either the first boundary groove or the second boundary groove is supplied to the other of the first boundary groove or the second boundary groove in a state in which the object is placed on the plurality of dots. The electrostatic chuck is characterized in that a space is formed between the first main surface and the object, the first range (range C1) having a predetermined unit area and including the first boundary, the first boundary groove, and the second boundary groove, a boundary groove occupancy rate in a first range (range C1) including the first boundary, the first boundary groove, and the second boundary groove is greater than an in-region groove occupancy rate in a second range (range D, D1) including the first region groove and having the same shape and dimensions as the first range, and the groove end distance between the first boundary groove and the second boundary groove is smaller than the groove end distance between the first boundary groove and the first region groove .

This electrostatic chuck does not have a seal ring disposed between each region to control the gas pressure in each region as in the conventional electrostatic chuck. That is, when the object W is placed, a closed space is formed by the object W and the ceramic dielectric substrate (first region and second region). Therefore, the problem of particles accumulating in the seal ring portion can be solved. On the other hand, simply not providing a seal ring makes it difficult to divide the gas pressure for each region, and the gas pressure controllability is reduced. Therefore, in the present invention, in addition to eliminating the seal ring, the groove end distance between the first boundary groove and the second boundary groove is designed to be smaller than the groove end distance between the first boundary groove and the first region groove adjacent to the first boundary groove.
In addition, with this electrostatic chuck, the area where the gas pressure changes near the boundary between regions can be made small, and the area where the gas pressure is at the intended pressure can be made large, thereby effectively controlling the gas pressure in each region while solving the problem of particle accumulation.

A second invention is an electrostatic chuck according to the first invention, characterized in that, when projected onto a plane perpendicular to a first direction from the base plate toward the ceramic dielectric substrate, at least a portion of the first gas introduction hole overlaps with the first boundary groove.

This electrostatic chuck has excellent gas controllability because the first boundary groove and the first gas introduction hole are directly connected. Therefore, the area where the gas pressure changes near the boundary between regions can be made smaller.

A third invention is an electrostatic chuck according to the first or second invention, characterized in that, when projected onto a plane perpendicular to a first direction from the base plate toward the ceramic dielectric substrate, at least a portion of the second gas inlet hole overlaps with the second boundary groove.

This electrostatic chuck can reduce the area where the gas pressure changes near the boundaries between regions.

A fourth invention is an electrostatic chuck according to any one of the first to third inventions, characterized in that an angle formed between a line connecting a center of the first gas inlet hole and a center of the second gas inlet hole and the first boundary is less than 90°.

This electrostatic chuck allows the boundary grooves to be closer together, making it possible to reduce the area where the gas pressure changes. This makes it possible to increase the area where the intended gas pressure is achieved.

A fifth invention is an electrostatic chuck according to any one of the first to third inventions, characterized in that an angle between a line connecting a center of the first gas inlet hole and a center of the second gas inlet hole and the first boundary is 90°.

This electrostatic chuck makes it easier to maintain the pressure in each area at a targeted level.

A sixth invention is an electrostatic chuck according to any one of the first to fifth inventions, further comprising a lift pin hole provided in the first main surface, wherein a distance between the lift pin hole and the first boundary groove is greater than a distance between the lift pin hole and the first region inner groove closest to the lift pin hole.

This electrostatic chuck can reduce pressure changes within the area.

A seventh invention is an electrostatic chuck according to any one of the first to sixth inventions, characterized in that the first main surface includes at least the first region, the second region located outside the first region, and a third region (region 103) located outside the second region and adjacent to the second region, the plurality of second grooves include a second outer boundary groove (groove 14a) provided closest to a second boundary between the second region and the third region and extending along the second boundary, the third region is provided with a third boundary groove (groove 14a) provided adjacent to the second boundary and extending along the second boundary, the electrostatic chuck has the predetermined unit area, and a boundary groove occupancy rate in a third range (range C2) including the second boundary, the second boundary groove, and the third boundary groove is greater than an intra-region groove occupancy rate in the first range (range C1).

This electrostatic chuck can reduce the area where the gas pressure changes near the boundaries between regions.

An eighth invention is an electrostatic chuck according to the seventh invention, further comprising an outer seal arranged to surround an outer edge of the first main surface, at least a portion of which is capable of contacting an object to be attracted, and in a second direction perpendicular to a first direction from the base plate to the ceramic dielectric substrate, a distance between the second boundary and the outer seal is smaller than a distance between the first boundary and the second boundary.

This electrostatic chuck can reduce the area where the gas pressure changes near the boundaries between regions.

According to an aspect of the present invention, an electrostatic chuck is provided that can effectively control the gas pressure in each region while suppressing particle accumulation in the seal ring portion.

1 is a schematic cross-sectional view illustrating an electrostatic chuck according to an embodiment of the present invention; A schematic cross-sectional view illustrating a ceramic dielectric substrate, an electrode, and a first porous portion. 1A is a schematic cross-sectional view illustrating an example of the arrangement of grooves and gas introduction holes according to a comparative example, and FIG. 1B is a schematic cross-sectional view illustrating an example of the arrangement of grooves and gas introduction holes according to the present embodiment. FIG. 11 is a graph showing the pressure in each region and the pressure at the boundary between the regions obtained by simulation. FIG. 13 is a graph illustrating the effect of boundary groove spacing. 1A is a graph illustrating the effect of the boundary groove interval by the "gradient deviation rate", and FIG. 1B is a graph explaining the "gradient deviation rate". FIG. 7 is an enlarged view of part H in FIG. FIG. 11 is a graph illustrating the effect of the number of second grooves (grooves 14a, 14b). 1A is a schematic cross-sectional view illustrating the arrangement of gas introduction holes according to another embodiment, and FIG. 1B is a schematic cross-sectional view illustrating the arrangement of gas introduction holes according to another embodiment. 13A and 13B are graphs showing the pressure in a region and the pressure at the boundary between regions obtained by simulation. FIG. 4 is a schematic plan view of a ceramic dielectric substrate according to another embodiment. 1A is a schematic plan view illustrating the arrangement of grooves according to a comparative example, and FIG. 1B is a schematic plan view illustrating the arrangement of grooves according to a comparative example. FIG. 11 is a graph illustrating the pressure change at the center of the substrate. 1A to 1C are schematic diagrams illustrating the configuration of the groove 14c. FIG. 4 is a schematic plan view of a ceramic dielectric substrate according to another embodiment. 1 is a schematic diagram illustrating a processing apparatus according to an embodiment of the present invention;

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are designated by the same reference numerals and detailed description thereof will be omitted as appropriate.
In each figure, the direction from the base plate 50 to the ceramic dielectric substrate 11 is the Z direction, one of the directions approximately perpendicular to the Z direction is the Y direction, and the direction approximately perpendicular to the Z direction and the Y direction is the X direction.

(Electrostatic chuck)
FIG. 1 is a schematic cross-sectional view illustrating an electrostatic chuck 1 according to the present embodiment.
FIG. 2 is a schematic cross-sectional view illustrating the ceramic dielectric substrate 11, the electrode 12, and the first porous portion 90.
As shown in FIG. 1, the electrostatic chuck 1 may include a ceramic dielectric substrate 11, an electrode 12, a first porous portion 90, a base plate 50, and a second porous portion 70.

As shown in Figs. 1 and 2, the ceramic dielectric substrate 11 can be, for example, a flat plate-shaped member using sintered ceramic. For example, the ceramic dielectric substrate 11 can contain aluminum oxide ( _Al2O3 ). For example, the ceramic dielectric substrate 11 can be formed using high-purity aluminum oxide. The concentration of aluminum oxide in the ceramic dielectric substrate 11 can be, for example, 99 atomic percent (atomic%) or more and ₁₀₀ atomic% or less. If high-purity aluminum oxide is used, the plasma resistance of the ceramic dielectric substrate 11 can be improved. The porosity of the ceramic dielectric substrate 11 can be, for example, 1% or less. The density of the ceramic dielectric substrate 11 can be, for example, 4.2 g/ ^cm3 .

The ceramic dielectric substrate 11 has a first main surface 11a on which an object W to be attracted is placed, and a second main surface 11b opposite the first main surface 11a. The first main surface 11a is the surface exposed to the outside of the electrostatic chuck 1. The object W can be, for example, a semiconductor substrate such as a silicon wafer, a glass substrate, etc.

The first main surface 11a of the ceramic dielectric substrate 11 is provided with a plurality of dots 13. The object W is placed on the plurality of dots 13 and is supported by the plurality of dots 13. If a plurality of dots 13 are provided, a space is formed between the back surface of the object W placed on the electrostatic chuck 1 and the first main surface 11a. By appropriately selecting the height, number, area ratio, shape, etc. of the dots 13, it is possible to make the particles adhering to the object W, for example, in a preferable state. For example, the height (dimension in the Z direction) of the plurality of dots 13 can be 1 μm or more and 100 μm or less, preferably 1 μm or more and 30 μm or less, and more preferably 5 μm or more and 15 μm or less.

A plurality of grooves 14a and 14b are provided on the first main surface 11a of the ceramic dielectric substrate 11. The plurality of grooves 14a and 14b are open to the first main surface 11a of the ceramic dielectric substrate 11. The width (dimension in the X direction or Y direction) of the groove 14a can be, for example, 0.1 mm or more and 2.0 mm or less, preferably 0.1 mm or more and 1.0 mm or less, and more preferably 0.2 mm or more and 0.5 mm or less. The depth (dimension in the Z direction) of the groove 14a can be, for example, 10 μm or more and 300 μm or less, preferably 10 μm or more and 200 μm or less, and more preferably 50 μm or more and 150 μm or less. The width (dimension in the X direction or Y direction) of the groove 14b can be, for example, 0.1 mm or more and 1.0 mm or less. The depth of the groove 14b (dimension in the Z direction) can be, for example, 0.1 mm or more and 2.0 mm or less, preferably 0.1 mm or more and 1.0 mm or less, and more preferably 0.2 mm or more and 0.5 mm or less.

The ceramic dielectric substrate 11 is provided with a plurality of gas introduction holes 15. One end of each of the plurality of gas introduction holes 15 can be connected to the groove 14a. The other end of each of the plurality of gas introduction holes 15 can be connected to a gas supply path 53 described later via a first porous portion 90. The gas introduction holes 15 are provided from the second main surface 11b to the first main surface 11a. That is, the gas introduction holes 15 extend in the Z direction between the second main surface 11b side and the first main surface 11a side, penetrating the ceramic dielectric substrate 11. The diameter of the gas introduction holes 15 can be, for example, 0.05 mm or more and 0.5 mm or less.
The grooves 14a, 14b and the gas introduction holes 15 will be described in detail later.

The electrode 12 is provided inside the ceramic dielectric substrate 11. The electrode 12 is provided between the first main surface 11a and the second main surface 11b of the ceramic dielectric substrate 11.
The shape of the electrode 12 may be, for example, a thin film along the first main surface 11a and the second main surface 11b of the ceramic dielectric substrate 11. The electrode 12 is an adsorption electrode for adsorbing and holding the object W. The electrode 12 may be of either a monopolar type or a bipolar type. The electrode 12 illustrated in Fig. 1 is of a bipolar type, and two electrodes 12 are provided on the same surface.

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

A power source 210 is electrically connected to the electrode 12 via a connection part 20. When a predetermined voltage is applied to the electrode 12, an electric charge can be generated in the area of the electrode 12 on the first main surface 11a side. Therefore, the object W is attracted and held on the first main surface 11a side of the ceramic dielectric substrate 11 by electrostatic force.

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

In the case of the first porous portion 90 illustrated in Figures 1 and 2, the first porous portion 90 is provided on the portion of the gas introduction hole 15 on the second main surface 11b side. One end of the first porous portion 90 is exposed to the second main surface 11b of the ceramic dielectric substrate 11. The other end of the first porous portion 90 is located between the first main surface 11a and the second main surface 11b. The other end of the first porous portion 90 may be exposed to the bottom surface of the groove 14a. In addition, both ends of the first porous portion 90 may be located between the first main surface 11a and the second main surface 11b.

The material of the first porous portion 90 may be, for example, ceramics having insulating properties. The first porous portion 90 may contain, for example, at least one of aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), and yttrium oxide (Y ₂ O ₃ ). In this way, the first porous portion 90 may have high dielectric strength and high rigidity.

In this case, the purity of the aluminum oxide of the ceramic dielectric substrate 11 can be made higher than the purity of the aluminum oxide of the first porous portion 90. In this way, the performance of the electrostatic chuck 1, such as plasma resistance, can be ensured, and the mechanical strength of the first porous portion 90 can be ensured. As an example, by adding a small amount of additive to the first porous portion 90, the sintering of the first porous portion 90 can be promoted, making it possible to control the pores and ensure the mechanical strength.

For example, the purity of ceramics such as aluminum oxide can be measured using X-ray fluorescence analysis, ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry), etc.

As shown in FIG. 1, the base plate 50 supports, for example, a ceramic dielectric substrate 11. The ceramic dielectric substrate 11 can be, for example, glued onto the base plate 50. The adhesive can be, for example, a silicone adhesive.

The base plate 50 is made of, for example, metal. The base plate 50 is divided into an upper portion 50a and a lower portion 50b, both made of, for example, aluminum, and a connection path 55 is provided between the upper portion 50a and the lower portion 50b. One end of the connection path 55 is connected to the input path 51, and the other end of the connection path 55 is connected to the output path 52.

The base plate 50 also serves to adjust the temperature of the dielectric substrate 11. For example, when cooling the dielectric substrate 11, a cooling medium flows in from the input path 51, passes through the connection path 55, and flows out from the output path 52. This allows the cooling medium to absorb heat from the base plate 50 and cool the ceramic dielectric substrate 11 mounted on it. Note that when keeping the dielectric substrate 11 warm, it is also possible to let a heat-retaining medium flow into the connection path 55. If the temperature of the dielectric substrate 11 can be controlled, it becomes easier to control the temperature of the object W adsorbed and held on the dielectric substrate 11.

Gas is supplied to the multiple grooves 14a, 14b. The supplied gas comes into contact with the object W, thereby controlling the temperature of the object W. In this case, if the temperature of the base plate 50 can be controlled, the range of temperature control by the gas supplied to the grooves 14a, 14b can be narrowed. For example, the temperature of the object W can be roughly controlled by the base plate 50, and the temperature of the object W can be precisely controlled by the gas supplied to the grooves 14a, 14b.

The base plate 50 may be provided with a plurality of gas supply paths 53. The gas supply paths 53 may be provided so as to penetrate the base plate 50. The gas supply paths 53 may not penetrate the base plate 50, but may branch off from the middle of another gas supply path 53 and be provided to the ceramic dielectric substrate 11 side.

The gas supply path 53 is connected to the gas introduction hole 15. That is, the gas that flows into the gas supply path 53 passes through the gas supply path 53 and then flows into the gas introduction hole 15.

The gas that flows into the gas inlet 15 passes through the gas inlet 15 and then flows into the groove 14a to which the gas inlet 15 is connected. This allows the object W to be directly cooled by the gas.

The second porous portion 70 can be provided between the first porous portion 90 and the gas supply path 53 in the Z direction. For example, the second porous portion 70 is fitted into the end face of the base plate 50 on the ceramic dielectric substrate 11 side. As shown in FIG. 1, for example, a countersunk portion 53a is provided on the end face of the base plate 50 on the ceramic dielectric substrate 11 side, and the second porous portion 70 can be fitted into the countersunk portion 53a. The countersunk portion 53a is connected to the gas supply path 53. The second porous portion 70 can be provided so as to face the first porous portion 90.

Next, the multiple grooves 14a, 14b and the multiple gas introduction holes 15 will be further described. As described above, the temperature of the object W can be controlled by the gas supplied to the multiple grooves 14a, 14b. During processing of the object W, a temperature distribution may occur within the surface of the object W. For example, low temperature areas and high temperature areas may occur within the surface of the object W. In this case, if the pressure of the gas in contact with the high temperature area is made higher than the pressure of the gas in contact with the low temperature area, the amount of heat dissipated from the high temperature area increases, so that the temperature of the object W can be controlled and the occurrence of a temperature distribution within the surface of the object W can be suppressed.

For example, the first main surface 11a side of the ceramic dielectric substrate 11 can be divided into multiple regions, and the in-plane temperature of the object W can be controlled by varying the pressure of the gas supplied to the multiple regions. In this case, in order to control the gas pressure in each region, a seal ring may be provided between each region to separate the regions. In this example, the top of the seal ring is brought into contact with the surface of the object W on the first main surface 11a side. In this way, the flow of gas between the regions can be almost eliminated, and the gas pressure in each region can be effectively controlled.

However, when a seal ring is provided, particles generated during the wafer processing process tend to accumulate in the seal ring area, which can cause defects in that area.

Therefore, in the present invention, a seal ring for dividing the regions is not provided, and the arrangement of the grooves 14a, 14b is devised. That is, when the object W is placed, a closed space is formed between the object W and the ceramic dielectric substrate 11 (e.g., the regions 101 and 102). According to the present invention, it is possible to effectively control the pressure within the regions, even without a seal ring.
In the present invention, it is sufficient to effectively control the gas pressure in each region without substantially providing a seal ring, and the present invention does not preclude the provision of a seal ring partially or locally. In other words, as long as the effect of effectively controlling the gas pressure in each region can be achieved without substantially providing a seal ring, the seal ring may be provided partially or locally.
FIG. 3A is a schematic cross-sectional view illustrating the arrangement of grooves 14 and gas introduction holes 15 according to a comparative example.
3A, the grooves 14 are provided at equal intervals in the X direction. That is, the distance L23 between the groove ends in the X direction is the same.

In this specification, the groove end distance refers to the shortest distance between the inner wall of one groove on the other groove side and the inner wall of the other groove on the one groove side when there are two adjacent grooves. In this case, if the groove end distance in the two grooves varies, the shortest distance can be regarded as the groove end distance.

In addition, in the X direction, regions 100a and 100b1 are adjacent to each other, and regions 100a and 100b2 are adjacent to each other. In the example shown in FIG. 3(a), gas introduction holes 15 are connected to two grooves 14 provided on either side of the boundary between regions 100a and 100b1.

The pressure of the gas supplied to the groove 14 provided in region 100a is P1, the pressure of the gas supplied to the groove 14 provided in region 100b1 is P2, and the pressure of the gas supplied to the groove 14 provided in region 100b2 is P3.

3B is a schematic cross-sectional view illustrating an example of the arrangement of the grooves 14a and 14b according to this embodiment and the arrangement of the gas introduction holes 15. The groove 14a is a boundary groove provided on either side of the boundary between different regions, and the groove 14b is an intra-region groove provided within a region other than the groove 14a.
In Fig. 3B, the distance between the groove ends (boundary groove interval) of two grooves 14a (boundary grooves) provided on either side of the boundary between the region 100a and the regions 100b1 and 100b2 in the X direction is L21, and the distance between the groove ends (intra-region groove interval) of the groove 14a (boundary groove) and a groove 14b (intra-region groove) other than the groove 14a provided in the region 100a adjacent to the boundary groove 14a is L22. In this case, L21 < L22. Also, the distance between the groove ends of the groove 14a (boundary groove) and a groove 14b other than the groove 14a provided in the regions 100b1 and 100b2 adjacent to the boundary groove 14a is L24.
The pressure of the gas supplied through the gas inlet 15 to the groove 14a provided in the region 100a is designated as P1, and the pressure of the gas supplied through the gas inlet 15 to the groove 14a provided in the region 100b1 is designated as P2.

4 is a graph showing the pressure in the region 100a, the pressure in the regions 100b1 and 100b2, and the pressure at the boundaries between the region 100a and the regions 100b1 and 100b2, which are obtained by simulation. In the simulation, it is assumed that an object W supported by dots 13 is located above the first main surface 11a of the ceramic dielectric substrate 11.
4A shows an example in which the grooves 14 and gas introduction holes 15 are arranged as shown in FIG. 3A, and the boundary groove interval is equal to the intra-region groove interval.
4B shows an example in which the arrangement of the grooves 14a and 14b, the arrangement of the gas introduction holes 15, and the boundary groove spacing are smaller than the intra-region groove spacing, as shown in FIG. 3B. In both examples, no seal ring is provided between the regions.
In the simulation, P1=3×P2, the groove end distance L21 is 5 mm, the groove end distance L22 is 20 mm, and the groove end distance L23 is 15 mm. The dimension of the region 100a in the X direction is 50 mm.

As can be seen from FIG. 4, when the boundary groove spacing is equal to the intra-region groove spacing (case A), the area where the gas pressure changes is large near the boundaries between region 100a and regions 100b1 and 100b2. In contrast, when the boundary groove spacing is smaller than the intra-region groove spacing (case B), the area where the gas pressure changes near the boundaries between region 100a and regions 100b1 and 100b2 can be made smaller than in case A. In other words, in each of regions 100a, 100b1 and 100b2, the area where the intended gas pressure is achieved can be made larger, and the uniformity of the gas pressure within the region can be improved.

As mentioned above, by devising an appropriate arrangement of grooves 14a and 14b, the temperature of the object W can be controlled by the gas pressure even when no seal ring is provided between the regions. Therefore, if the uniformity of the gas pressure within a region can be increased, the temperature of the object W in the part corresponding to that region can be controlled more effectively. In addition, the occurrence of an in-plane distribution in the temperature of the object W can be suppressed.

In addition, according to the knowledge of the inventors, if the gas introduction hole 15 is connected to at least one of the two boundary grooves 14a provided on either side of the boundary, the above-mentioned effect can be obtained, which is preferable.

In this case, there is a gap between the first main surface 11a and the object W that is the height of the dots 13, so the gas supplied to the groove 14a to which the gas inlet 15 is connected is supplied to the groove 14b and other grooves 14a through the gap. That is, in each region, gas is supplied to the space formed between the back surface of the object W and the first main surface 11a including the grooves 14a and 14b.

3B, when the gas introduction holes 15 are connected to the two grooves 14a on either side of the boundary, the change in gas pressure at the boundary between the regions can be made more pronounced, and the temperature of the object W can be more effectively controlled, which is more preferable. Also, the occurrence of in-plane distribution of the temperature of the object W can be more effectively suppressed.

FIG. 5 is a graph for illustrating the effect of boundary groove spacing.
The boundary groove interval on the horizontal axis is the distance between the groove ends of two grooves (boundary grooves) provided on either side of the boundary between adjacent regions. The effect of the boundary groove interval is the effect of the boundary groove interval itself, and can be applied to, for example, the distance L23 illustrated in FIG. 3(a) or the distance L21 illustrated in FIG. 3(b).
The deviation rate on the vertical axis indicates the degree to which the average pressure in each region deviates from the set pressure (intended pressure). The larger the deviation rate, the larger the difference between the average pressure in each region and the intended pressure.
FIG. 5 shows the deviation rate obtained by simulation, for example, when the pressure P1 in the region 100a in FIGS. 3A and 3B is set to 20 Torr (2666.4 Pa) and the pressure P3 in the region 100b2 is set to 60 Torr (7999.2 Pa).

As can be seen from Fig. 5, if the boundary groove interval, which is the distance between the groove ends of the boundary grooves, is more than 0 mm and not more than 60 mm, preferably more than 0 mm and not more than 20 mm, the deviation rate increases almost linearly. If the boundary groove interval exceeds 60 mm, the deviation rate increases exponentially. This means that if the boundary groove interval is 60 mm or less, preferably 20 mm or less, the increase in the deviation rate can be suppressed, and the average pressure in each region becomes closer to the intended pressure.
As described above, the effect of the boundary groove spacing is the effect of the boundary groove spacing itself, so by appropriately combining the arrangement of grooves 14a, 14b described above, the arrangement of gas inlet hole 15 described above (connecting gas inlet hole 15 to the boundary groove), and groove 14c described below, it is possible to more effectively control the gas pressure in each region while effectively suppressing the accumulation of particles in the seal ring portion.

FIG. 6A is a graph illustrating the effect of the boundary groove interval by the "slope deviation rate."
FIG. 6B is a graph for explaining the "slope deviation rate."
FIG. 7 is an enlarged view of a portion H in FIG.
If the pressure in the first region and the pressure in the second region are ideally separated, the pressure distribution at the first boundary between the first region and the second region is considered to be distributed on a straight line (change linearly) as shown in Fig. 6(b). Therefore, the effect of the boundary groove spacing can be evaluated by arithmetically calculating the slope from the pressure distribution between the regions obtained by analysis and determining the deviation rate (slope deviation rate) between this and the ideal slope.

As can be seen from Fig. 6(a), if the boundary groove interval, which is the distance between the groove ends of the boundary grooves, is more than 0 mm and is 60 mm or less, the slope deviation rate increases almost linearly. If the boundary groove interval exceeds 60 mm, the slope deviation rate increases exponentially. This means that if the boundary groove interval is 60 mm or less, the increase in the slope deviation rate can be suppressed, and the average pressure in each region becomes closer to the intended pressure.
Furthermore, as can be seen from Fig. 7, if the boundary groove interval, which is the distance between the groove ends of the boundary grooves, is more than 0 mm and 20 mm or less, the slope deviation rate can be made even closer to a linear slope. This means that if the boundary groove interval is 20 mm or less, the increase in the slope deviation rate can be further suppressed, and therefore the average pressure in each region becomes even closer to the intended pressure.

FIG. 8 is a graph for illustrating the effect of the number of second grooves (grooves 14a, 14b (radial grooves)).
As can be seen from Fig. 8, if at least two second grooves are provided in the second region, the deviation rate can be significantly reduced. In other words, the pressure at the first boundary (boundary 102a) between the first region (region 101) and the second region (region 102) can be made closer to the average value of the pressure in the first region and the pressure in the second region. This makes it easier to maintain the pressure in each region at a desired pressure.

According to the findings of the inventors, if the boundary groove occupancy rate is greater than the intra-region groove occupancy rate, the effect illustrated in FIG. 4 can be obtained. In other words, if the boundary groove occupancy rate is greater than the intra-region groove occupancy rate, the area in the vicinity of the boundary where the gas pressure changes can be reduced. Therefore, the area where the intended gas pressure is achieved can be increased, and the temperature of the object W can be effectively controlled. In addition, the occurrence of an in-plane distribution in the temperature of the object W can be suppressed.

FIG. 9A is a schematic cross-sectional view illustrating the arrangement of the gas introduction holes 15. FIG.
In FIG. 9A, the region 100a is adjacent to the region 100b1, and the region 100a is adjacent to the region 100b2 in the X direction. In addition, two grooves 14a (boundary grooves) are provided on either side of the boundary between the region 100a and the regions 100b1 and 100b2 in the X direction. In addition, grooves 14b (intra-region grooves) are provided inside the region 100a and inside the regions 100b1 and 100b2. In the region 100a, the gas introduction hole 15 is connected to the groove 14a on the region 100b1 side, and the gas introduction hole 15 is not connected to the groove 14a on the region 100b2 side. In the region 100b1, the gas introduction hole 15 is connected to the groove 14a on the region 100a side. In the region 100b2, the gas introduction hole 15 is connected to the groove 14a on the region 100a side. That is, in the region 100a, the gas introduction hole 15 is connected to only one of the grooves 14a.
The pressure of the gas supplied to the grooves 14a provided in the region 100a is designated as P1, and the pressure of the gas supplied to the grooves 14a provided in the regions 100b1 and 100b2 is designated as P2.

FIG. 9B is a schematic cross-sectional view illustrating the arrangement of gas introduction holes 15 according to another embodiment.
In FIG. 9B, in the region 100a, the gas introduction holes 15 are connected to the grooves 14a on the region 100b1 side and the grooves 14a on the region 100b2 side.
The pressure of the gas supplied to the grooves 14a provided in the region 100a is designated as P1, and the pressure of the gas supplied to the grooves 14a provided in the regions 100b1 and 100b2 is designated as P2.

10(a) and (b) are graphs showing the pressure in the region 100a, the pressure in the regions 100b1 and 100b2, and the pressure at the boundaries between the region 100a and the regions 100b1 and 100b2, which are obtained by simulation. In the simulation, it is assumed that an object W supported by dots 13 is located above the first main surface 11a of the ceramic dielectric substrate 11.
FIG. 10A shows the case of FIG.
FIG. 10B shows the case of FIG.
In addition, P1=3×P2, and the dimension of the region 100a in the X direction is 50 mm.

As shown in Fig. 9A, in the region 100b2 side of the region 100a, the gas introduction hole 15 is not connected to the groove 14a, so that the region where the gas pressure changes near the boundary becomes large as can be seen from Fig. 10A, and therefore the region where the intended gas pressure is achieved becomes small.
On the other hand, on the side of region 100a facing region 100b1, gas inlet hole 15 is connected to groove 14a, so that the region in which the gas pressure changes near the boundary is small, as can be seen from Fig. 10A. Therefore, the region in which the intended gas pressure is achieved can be enlarged.
Furthermore, as can be seen from FIG. 10(b), if a gas introduction hole 15 is connected to each of the two grooves 14a provided on either side of the boundary, the area where the intended gas pressure is achieved can be further enlarged, which is more preferable.

As described above, the temperature of the object W can be controlled by the gas pressure. Therefore, if the area where the intended gas pressure is applied can be enlarged, the temperature of the object W can be effectively controlled. In addition, the occurrence of an in-plane distribution in the temperature of the object W can be suppressed.
As described above, it is preferable that the gas introduction hole 15 is connected to the groove 14a (boundary groove). It is more preferable that the gas introduction hole 15 is connected to each of the two grooves 14a provided on either side of the boundary. In the example shown in FIG. 9B, two gas introduction holes 15 are provided in the region 100a. For example, both of the two gas introduction holes 15 may be connected to one gas supply path 53 (see FIG. 1).

Furthermore, when gas introduction holes 15 are connected to each of two grooves 14a provided on either side of a boundary, the angle formed by a line connecting the center of gas introduction hole 15 connected to one groove 14a and the center of gas introduction hole 15 connected to the other groove 14a and the boundary can be less than 90°. In this case, the angle can be, for example, 1.0° to 89°, preferably 2.0° to 70°, and more preferably 3.0° to 60°.
In this way, the boundary grooves can be brought closer to each other, and the area where the gas pressure changes can be reduced, thereby making it possible to increase the area where the intended gas pressure is achieved.

The angle between the line connecting the center of the gas inlet hole 15 connected to one groove 14a and the center of the gas inlet hole 15 connected to the other groove 14a and the boundary may be 90°. In this case, the angle need not be 90° in the strict sense, and a difference of, for example, the order of a manufacturing error may be allowed.
In this way, by arranging the two gas introduction holes 15 at opposing positions, the gases with different pressures supplied from the two gas introduction holes 15 compete with each other, making it easier to maintain the pressure in each region at a desired pressure.

11 is a schematic plan view of a ceramic dielectric substrate 11 according to another embodiment of the present invention, which is the same as the ceramic dielectric substrate 11 shown in FIG.
11, a plurality of grooves 14c may be further provided on the first main surface 11a of the ceramic dielectric substrate 11. The width of the grooves 14c (the dimension in a direction substantially perpendicular to the extension direction of the grooves) may be, for example, 0.1 mm or more and 1 mm or less. The depth of the grooves 14c (the dimension in the Z direction) may be, for example, 50 μm or more and 150 μm or less.

In this example, at least one groove 14c is provided in each of the regions 101, 102, and 104. The groove 14c connects multiple grooves 14a and 14b provided in one region. Therefore, the gas supplied to the groove 14a connected to the gas introduction hole 15 flows along the groove 14a and is supplied to the groove 14b and other grooves 14a via the groove 14c. If the groove 14c is provided, the flow of gas can be made smooth, so that even if there is no seal ring, the occurrence of pressure distribution in the region can be suppressed. In addition, even if the top of the dot 13 wears and the gap between the object W and the first main surface 11a becomes narrow, gas can be supplied to the groove 14b and other grooves 14a via the groove 14c.

The groove 14c is disposed so as to communicate with the groove 14a and the groove 14b. The groove 14c may extend in a direction intersecting the grooves 14a and 14b, for example.
For example, as shown in FIG. 11, the plurality of grooves 14c can be provided on a line passing through the center of the ceramic dielectric substrate 11. The plurality of grooves 14c do not necessarily have to be provided on a line passing through the center of the ceramic dielectric substrate 11. Although the linear grooves 14c are illustrated, the grooves 14c may be curved or may have linear and curved portions within a range in which the grooves 14c can communicate with the grooves 14a and 14b. The number, arrangement, shape, etc. of the plurality of grooves 14c can be appropriately changed depending on the size of the object W, the required specifications for the temperature distribution in the object W, etc. The number, arrangement, shape, etc. of the plurality of grooves 14c can be appropriately determined, for example, by performing experiments or simulations.

In the embodiment of the present invention in which a seal ring is not provided, some measures are taken to improve the response to the gas pressure in the region. As an example, by providing groove 14c that communicates with groove 14a and groove 14b, the gas pressure in the region can be effectively controlled.
In addition, since there is a gap between the first main surface 11a and the object W by the height of the dots 13, the gas supplied to the groove 14a connected to the gas introduction hole 15 is supplied to the groove 14b and other grooves 14a through the gap. However, if the top of the dot 13 is worn down and the gap between the object W and the first main surface 11a is narrowed, the flow of gas in each region is hindered, and there is a risk of pressure distribution occurring. If the groove 14c is provided, even if the top of the dot 13 is worn down and the gap between the object W and the first main surface 11a is narrowed, gas can be supplied to the groove 14b and other grooves 14a through the groove 14c. Therefore, it is possible to significantly shorten the time until the pressure in the region reaches a predetermined pressure, and to suppress the occurrence of pressure distribution in the region.

Furthermore, as shown in FIG. 11 , at least two gas inlet holes 15 (first gas inlet holes) capable of supplying gas can be provided in groove 14a (first boundary groove) that is provided in region 101 (first region) closest to boundary 102a (first boundary) between region 101 and region 102 (second region) and extends along boundary 102a.
In recent years, the density of semiconductor integrated circuits has been further increased, and plasma density has also been increased in order to achieve even finer processing. If the diameter of gas introduction holes 15 is reduced in order to suppress arcing under this high-density plasma, there is a risk that individual differences will occur in each gas introduction hole 15 due to manufacturing variations, etc. According to this embodiment, the effect of the variation in the diameter of each gas introduction hole 15 can be suppressed, and a predetermined flow rate of gas can be more reliably supplied to groove 14a extending along boundary 102a.

11, at least two gas introduction holes 15 (second gas introduction holes) capable of supplying gas can be provided in a groove 14a (second boundary groove) that is provided in the region 102 closest to the boundary 102a and extends along the boundary 102a. In the example shown in FIG. 11, three gas introduction holes 15 are provided.
In this manner, similarly to the above, the influence of variations in the hole diameter of each gas introduction hole 15 can be suppressed, and gas can be more reliably supplied to the groove 14a extending along the boundary 102a.

Next, the effect of the groove 14c will be further described.
FIG. 12A is a schematic plan view for illustrating the arrangement of grooves 14 according to the comparative example.
In Fig. 12(a), a plurality of grooves 14 are provided on the surface of a substrate 110. The plurality of grooves 14 are annular and are provided at equal intervals concentrically about a center 110a of the substrate 110. Note that in Fig. 12(a), a groove 14c is not provided.
FIG. 12B is a schematic plan view illustrating the arrangement of the grooves 14 and the grooves 14c.
12(b), there are provided a plurality of grooves 14 and a plurality of grooves 14c that at least partially connect the plurality of grooves 14. In this example, the grooves 14c are provided on a line passing through the center 110a of the substrate 110. The plurality of grooves 14 are connected to each other via the grooves 14c.

Fig. 13 is a graph illustrating the pressure change at the center 110a of the substrate 110. Fig. 13 is a graph obtained by simulation of the pressure change at the center 110a of the substrate 110. In the simulation, it is assumed that an object W supported by dots 13 is located above the substrate 110.
E in FIG. 13 is a case where a plurality of grooves 14 as exemplified in FIG. 12(a) are provided.
13F shows a case where a plurality of grooves 14 and a plurality of grooves 14c as shown in FIG. 12B are provided.

As can be seen from Fig. 13, in the case of the example shown in Fig. 12(a) (case E), the pressure could only be increased to 95% of the predetermined pressure (20 Torr), which means that a pressure distribution may occur within the region.
In the case of the example shown in Fig. 12(b) (case F), the pressure could be increased to a predetermined pressure (20 Torr), which means that the occurrence of pressure distribution within the region could be suppressed.
Furthermore, in the case of F, the time T1 required to increase the pressure to a predetermined pressure is shorter than the time T2 required to increase the pressure to 95% of the predetermined pressure in the case of E. This means that the time required for the pressure in the region to reach the predetermined pressure can be significantly shortened, in other words, the responsiveness of gas control and therefore temperature control can be improved.

As mentioned above, it is preferable that the gas introduction hole 15 is connected to at least one of the two grooves 14a provided on either side of the boundaries 101a to 103a.

For example, as illustrated in FIG. 11, in the inner regions 101, 102, and 104 of the first main surface 11a, the gas inlet hole 15 can be connected to the outermost groove 14a in each region. In the outermost region 103 of the first main surface 11a, the gas inlet hole 15 can be connected to the innermost groove 14a.

The number and arrangement of the gas introduction holes 15 provided in each region can be changed as appropriate depending on the size of the object W and the required specifications for the temperature distribution in the object W. For example, as illustrated in FIG. 11, three gas introduction holes 15 can be provided at equal intervals in one region. In this case, at least one of the multiple gas introduction holes 15 provided in region 103 and the gas introduction hole 15 provided in region 102 can be arranged on a line passing through the center of the first main surface 11a.

The above is a case where the area where the gas pressure changes near the boundary is reduced, but considering that gas is supplied to grooves 14a and 14c provided in the area, it is preferable to provide gas inlet 15 at the position where grooves 14a and 14c intersect, or in the vicinity of that position. For example, when projected onto a plane perpendicular to the Z direction, at least a portion of gas inlet 15 can be made to overlap with at least one of grooves 14a and 14c in the portion where grooves 14a and 14c are connected. In this way, it becomes easier to make the gas supplied to groove 14a flow out toward groove 14c. Therefore, it becomes easier to obtain the effect of groove 14c described above.

14(a) to (c) are schematic views illustrating the form of the groove 14c.
FIG. 14B is an enlarged view of a portion E in FIG.
FIG. 14C is an enlarged view of a portion F in FIG.
14(b), the groove 14c can be provided, for example, so as to overlap with a line drawn from the center toward the outer periphery of the ceramic dielectric substrate 11. In this case, at the portion where the groove 14a and the groove 14c are connected, the angle between the tangent line of the groove 14a and the groove 14c can be 90°.
14(c), the groove 14c may be arranged so as not to overlap, for example, a line drawn from the center to the outer periphery of the ceramic dielectric substrate 11. In this case, the angle between the tangent line of the groove 14a and the groove 14c at the portion where the groove 14a and the groove 14c are connected is not 90°.

FIG. 15 is a schematic plan view of a ceramic dielectric substrate 11 according to another embodiment.
In the case of the example shown in FIG. 11, the first main surface 11a is divided into a plurality of regions 101 to 104 in a concentric manner. In contrast, in the case of the example shown in FIG. 15, the first main surface 11a is divided into a plurality of regions 105 that are in close contact with each other. The plurality of regions 105 can be arranged side by side. There is no particular limitation on the outer shape of the plurality of regions 105, but it is preferable that the plurality of regions 105 have a shape that allows them to be in close contact with each other. The plurality of regions 105 can be, for example, polygonal, such as a triangle or a rectangle. The outer shape of the region 105 shown in FIG. 15 is a regular hexagon. The outer shape, number, arrangement, etc. of the plurality of regions 105 can be appropriately changed depending on the size of the object W, the required specifications for the temperature distribution in the object W, etc. The outer shape, number, arrangement, etc. of the plurality of regions 105 can be appropriately determined, for example, by performing experiments or simulations.

Groove 14a is provided along boundary 105a of region 105. Groove 14a is provided on both sides of boundary 105a. At least one groove 14b is provided in region 105. Groove 14b can be provided concentrically with groove 14a. The number and positions of grooves 14b provided in one region can be changed as appropriate depending on the size of object W and the required specifications for temperature distribution in object W. The number and positions of grooves 14b provided in one region can be determined as appropriate, for example, by conducting experiments or simulations.

Other features, such as grooves 14c, gas introduction holes 15, dots 13, lift pin holes 16, and outer seals 17, can be provided, as described above.

(Processing Equipment)
FIG. 16 is a schematic diagram illustrating a processing device 200 according to this embodiment.
As shown in FIG. 16, the processing apparatus 200 may include an electrostatic chuck 1 , a power supply 210 , a media supply unit 220 , and a supply unit 230 .
The power supply 210 is electrically connected to the electrode 12 provided in the electrostatic chuck 1. The power supply 210 may be, for example, a DC power supply. The power supply 210 applies a predetermined voltage to the electrode 12. The power supply 210 may also be provided with a switch that switches between applying a voltage and stopping the application of the voltage.

The medium supply unit 220 is connected to the input path 51 and the output path 52. The medium supply unit 220 can supply, for example, a liquid that serves as a cooling medium or a heat retention medium.
The medium supply unit 220 includes, for example, a storage unit 221 , a control valve 222 , and a discharge unit 223 .

The storage unit 221 can be, for example, a tank for storing liquid or factory piping. The storage unit 221 can also be provided with a cooling device or a heating device for controlling the temperature of the liquid. The storage unit 221 can also be equipped with a pump for pumping the liquid.

The control valve 222 is connected between the input path 51 and the storage section 221. The control valve 222 can control at least one of the flow rate and pressure of the liquid. The control valve 222 can also switch between supplying and stopping the supply of liquid.

The discharge section 223 is connected to the output path 52. The discharge section 223 can be a tank or a drain pipe that collects the liquid discharged from the output path 52. Note that the discharge section 223 is not necessarily required, and the liquid discharged from the output path 52 may be supplied to the storage section 221. In this way, the cooling medium or heat-retaining medium can be circulated, thereby saving resources.

The supply unit 230 includes a gas supply unit 231 and a gas control unit 232 .
The gas supply unit 231 may be a high-pressure cylinder storing a gas such as helium, factory piping, etc. Although the example shows a case where one gas supply unit 231 is provided, a plurality of gas supply units 231 may be provided.

The gas control unit 232 is connected between the multiple gas supply paths 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. The gas control unit 232 can also have a function of switching between supplying and stopping the gas supply. The gas control unit 232 can be, for example, a mass flow controller or a mass flow meter.

As shown in FIG. 16, a plurality of gas control units 232 can be provided. For example, a gas control unit 232 can be provided for each of the plurality of regions 101-104. In this way, the gas supply can be controlled for each of the plurality of regions 101-104. In this case, a gas control unit 232 can also be provided for each of the plurality of gas supply paths 53. In this way, gas control in the plurality of regions 101-104 can be performed more precisely. Although the above example shows a case where a plurality of gas control units 232 are provided, a single gas control unit 232 may be provided as long as it is capable of independently controlling the supply of gas in the plurality of supply systems.

Means for holding the object W include a vacuum chuck and a mechanical chuck. However, a vacuum chuck cannot be used in an environment where the pressure is reduced below atmospheric pressure. Furthermore, the use of a mechanical chuck may damage the object W or generate particles. For this reason, electrostatic chucks are used in processing equipment used in semiconductor manufacturing processes, for example.

In such a processing apparatus, it is necessary to isolate the processing space from the external environment. For this reason, the processing apparatus 200 may further include a chamber 240. The chamber 240 may have, for example, an airtight structure capable of maintaining an atmosphere at a reduced pressure lower than atmospheric pressure.
The processing device 200 may also include a plurality of lift pins and a drive device for raising and lowering the plurality of lift pins. When receiving the object W from the transport device or transferring the object W to the transport device, the lift pins are raised by the drive device and protrude from the first main surface 11a. When placing the object W received from the transport device on the first main surface 11a, the lift pins are lowered by the drive device and stored inside the ceramic dielectric substrate 11.

In addition, the processing apparatus 200 can be equipped with various devices depending on the content of the processing. For example, a vacuum pump that evacuates the inside of the chamber 240 can be provided. A plasma generating device that generates plasma can be provided inside the chamber 240. A process gas supply unit that supplies process gas to the inside of the chamber 240 can be provided. A heater that heats the object W and the process gas inside the chamber 240 can also be provided. Note that the devices provided in the processing apparatus 200 are not limited to those exemplified. Since known technology can be applied to the devices provided in the processing apparatus 200, detailed explanations will be omitted.

As described above, the processing apparatus 200 according to this embodiment includes the electrostatic chuck 1 described above and a gas control unit (gas control unit 232) capable of independently controlling the gas supplied to the first gas introduction hole (gas introduction hole 15) and the second gas introduction hole (gas introduction hole 15) provided in the electrostatic chuck 1. The processing apparatus 200 according to this embodiment can ensure that the gas pressure in each region is appropriate.

The above describes the embodiments of the present invention. However, the present invention is not limited to these descriptions. For example, the electrostatic chuck 1 is configured to use Coulomb force, but it may be configured to use Johnsen-Rahbek force. In addition, designs modified by a person skilled in the art as appropriate for the above-described embodiments are also included within the scope of the present invention as long as they include the features of the present invention. In addition, the elements of each of the above-described embodiments can be combined to the extent technically possible, and combinations of these are also included within the scope of the present invention as long as they include the features of the present invention.

1 electrostatic chuck, 11 ceramic dielectric substrate, 11a first main surface, 11b second main surface, 12 electrode, 13 dot, 14a-14c groove, 15 gas inlet hole, 16 lift pin hole, 17 outer seal, 50 base plate, 51 input path, 52 output path, 53 gas supply path, 70 second porous portion, 90 first porous portion, 101-104 region, 101a-103a boundary, 200 processing device, 231 gas supply unit, 232 gas control unit, W object

Claims (8)

A base plate;
a ceramic dielectric substrate provided on the base plate and having a first main surface exposed to the outside;
Equipped with
the first main surface includes a plurality of dots on which objects can be placed, at least a first region, a second region located outside the first region and adjacent to the first region, and a fourth region located inside the first region and adjacent to the first region;
a plurality of first grooves and at least one first gas introduction hole connected to at least one of the plurality of first grooves are provided in the first region of the first main surface;
The plurality of first grooves are
a first boundary groove disposed proximate to a first boundary between the first region and the second region and extending along the first boundary;
a fourth boundary groove disposed closest to a fourth boundary between the first region and the fourth region and extending along the fourth boundary;
at least one first region groove different from the first boundary groove and the fourth boundary groove;
a plurality of second grooves and at least one second gas introduction hole connected to at least one of the plurality of second grooves are provided in the second region of the first main surface;
the plurality of second grooves include a second boundary groove disposed closest to the first boundary and extending along the first boundary;
a space is formed between the first main surface and the object such that, in a state in which the object is placed on the plurality of dots, a gas supplied to one of the first boundary groove and the second boundary groove is supplied to the other of the first boundary groove and the second boundary groove;
a boundary groove occupancy rate in a first region having a predetermined unit area and including the first boundary, the first boundary groove, and the second boundary groove is greater than an intra-region groove occupancy rate in a second region including the first intra-region groove and having the same shape and dimensions as the first region;
An electrostatic chuck , characterized in that a groove end distance between the first boundary groove and the second boundary groove is smaller than a groove end distance between the first boundary groove and the first region inner groove. 2. The electrostatic chuck according to claim 1, wherein at least a portion of the first gas introduction hole overlaps with the first boundary groove when projected onto a plane perpendicular to a first direction from the base plate toward the ceramic dielectric substrate . 3. The electrostatic chuck according to claim 1, wherein when projected onto a plane perpendicular to a first direction from the base plate toward the ceramic dielectric substrate, at least a portion of the second gas introduction hole overlaps with the second boundary groove. 4. The electrostatic chuck according to claim 1, wherein an angle between a line connecting a center of the first gas inlet hole and a center of the second gas inlet hole and the first boundary is less than 90°. 4. The electrostatic chuck according to claim 1 , wherein an angle between a line connecting a center of the first gas inlet hole and a center of the second gas inlet hole and the first boundary is 90 degrees. Further comprising a lift pin hole provided in the first main surface,
6. The electrostatic chuck according to claim 1, wherein a distance between the lift pin hole and the first boundary groove is greater than a distance between the lift pin hole and the first region inner groove closest to the lift pin hole. the first main surface includes at least the first region, the second region located outside the first region, and a third region located outside the second region and adjacent to the second region,
the plurality of second grooves includes a second outer boundary groove disposed proximate to and extending along a second boundary between the second region and the third region;
The third region is provided with a third boundary groove adjacent to the second boundary and extending along the second boundary,
7. An electrostatic chuck as described in any one of claims 1 to 6, characterized in that a boundary groove occupancy rate in a third range having the specified unit area and including the second boundary, the second outer boundary groove, and the third boundary groove is greater than an in-region groove occupancy rate in the second range. an outer seal provided around a periphery of the first main surface, at least a portion of which can come into contact with an object to be attracted;
In a second direction perpendicular to the first direction from the base plate toward the ceramic dielectric substrate,
8. The electrostatic chuck of claim 7 , wherein a distance between the second boundary and the outer seal is less than a distance between the first boundary and the second boundary.

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