Electrostatic chuck member and electrostatic chuck device

Abstract

An electrostatic chuck member and an electrostatic chuck device capable of enhancing the cooling effect are provided. [Solution] An electrostatic chuck member for adsorbing an object to be adsorbed, comprising: a plate-shaped dielectric substrate having an opposing surface facing the object to be adsorbed, a plurality of protrusions protruding from the opposing surface and supporting the object to be adsorbed at their tips, and gas holes opening in the opposing surface; an electrostatic adsorption electrode arranged inside the dielectric substrate; and a porous body inserted into the gas holes, wherein the outer surface area of ​​the exposed portion of the porous body that is exposed from the opening of the gas holes is larger than the opening area of ​​the gas holes.

Description

[Technical Field]

[0001] The present invention relates to an electrostatic chuck member and an electrostatic chuck device. [Background technology]

[0002] In semiconductor manufacturing processes, electrostatic chuck devices are used to hold semiconductor wafers in a vacuum environment. A plate-shaped sample, such as a semiconductor wafer, is placed on one side of the electrostatic chuck device, and electrostatic force is generated between the plate-shaped sample and an internal electrode to attract and fix the plate-shaped sample. Furthermore, some electrostatic chuck devices are provided with gas holes for supplying cooling gas to cool the mounted wafer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6634315 Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, gas holes may become the starting point of abnormal discharge that can lead to damage to the wafer. One possible solution to this problem is to insert a porous body into the gas holes, but this reduces the flow rate of the cooling gas blown out from the gas holes, which reduces the cooling effect of the cooling gas on the wafer.

[0005] An object of the present invention is to provide an electrostatic chuck member and an electrostatic chuck device that can enhance the cooling effect while suppressing abnormal discharge. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the present invention includes the following aspects.

[0007] [1] An electrostatic chuck member that attracts an object to be attracted, a plate-like dielectric substrate having a surface facing the object to be attracted, a plurality of protrusions protruding from the surface and supporting the object to be attracted at their tips, and gas holes opening in the surface; an electrostatic attraction electrode disposed inside the dielectric substrate; a porous body inserted into the gas hole, an outer surface area of ​​an exposed portion of the outer shape of the porous body that is exposed from the opening of the gas hole is larger than the opening area of ​​the gas hole. [2] The electrostatic chuck member according to [1], wherein the outer surface area is 20% or more larger than the opening area. [3] The electrostatic chuck member according to [1] or [2], wherein the exposed portion protrudes from the opposing surface in the thickness direction of the dielectric substrate. [4] The exposed portion is provided with a recessed portion recessed in a thickness direction of the dielectric substrate, The electrostatic chuck member according to [1] or [2], wherein the depth of the recess in the thickness direction is greater than the protrusion height of the protrusion. [5] The electrostatic chuck member according to any one of [1] to [4], wherein the gas holes have a flow path cross-sectional area that increases toward the opening in the thickness direction of the dielectric substrate. [6] An electrostatic chuck member according to any one of [1] to [5], a base supporting the electrostatic chuck member from the opposite side of the facing surface. [Effects of the Invention]

[0008] According to one aspect of the present invention, there are provided an electrostatic chuck member and an electrostatic chuck device that can enhance the cooling effect while suppressing abnormal discharge. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing an electrostatic chuck device according to one embodiment. [Figure 2]FIG. 2 is a partial cross-sectional schematic view of an electrostatic chuck member according to one embodiment. [Figure 3] FIG. 3 is a partial cross-sectional schematic view of an electrostatic chuck member according to the first modification. [Figure 4] FIG. 4 is a partial cross-sectional schematic view of an electrostatic chuck member according to the second modification. [Figure 5] FIG. 5 is a partial cross-sectional schematic view of an electrostatic chuck member according to a third modification. [Figure 6] FIG. 6 is a partial cross-sectional schematic view of an electrostatic chuck member according to a fourth modification. [Figure 7] FIG. 7 is a partial cross-sectional schematic view of an electrostatic chuck member according to a fifth modification. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the electrostatic chuck device of the present invention will be described with reference to the drawings. In all of the drawings, the dimensions and proportions of the components may be displayed differently as appropriate to make the drawings easier to understand.

[0011] FIG. 1 is a schematic cross-sectional view showing an electrostatic chuck device 1 of the present embodiment. The electrostatic chuck device 1 includes an electrostatic chuck member 2 on which a wafer (object to be attracted) W is mounted, a base 3 that supports the electrostatic chuck member 2 from the opposite side of the wafer W, and a power supply terminal 16 that applies a voltage to the electrostatic chuck member 2. A focus ring that surrounds the wafer W may be disposed on the outer periphery of the upper surface of the electrostatic chuck member 2.

[0012] The electrostatic chuck member 2 includes a dielectric substrate 11, an electrostatic attraction electrode 13 located inside the dielectric substrate 11, and a porous body .

[0013] In the following description, each part of the electrostatic chuck device 1 will be described with the side on which the wafer W is mounted relative to the dielectric substrate 11 as the upper side and the side facing the base 3 as the lower side. That is, the vertical direction of the electrostatic chuck member 2 is the thickness direction Z of the dielectric substrate 11. Note that the vertical direction here is used merely for the sake of simplicity of description and does not limit the position of the electrostatic chuck device 1 during use.

[0014] Heat-resistant ceramics are preferably used as the material for forming the dielectric substrate 11. Suitable ceramic materials for forming the dielectric substrate 11 include, for example, aluminum oxide (Al2O3) sintered body, aluminum nitride (AlN) sintered body, and aluminum oxide (Al2O3)-silicon carbide (SiC) composite sintered body.

[0015] The dielectric substrate 11 is formed, for example, by applying an unsintered paste that forms the electrostatic attraction electrodes 13 and an unsintered paste that forms a bonding layer that bonds the ceramic plates together between ceramic plates that have been previously sintered, stacking them in the thickness direction, and integrating them by hot pressing under high temperature and high pressure.

[0016] The dielectric substrate 11 of this embodiment has a circular plate shape in a plan view. The dielectric substrate 11 has a facing surface 2s facing the wafer W, a back surface 2p facing the opposite side of the facing surface 2s, a plurality of protrusions 2a protruding from the facing surface 2s, and first gas holes (gas holes) 31 opening in the facing surface 2s. The facing surface 2s and the back surface 2p each extend along a plane perpendicular to the thickness direction Z of the dielectric substrate 11. For example, the plurality of protrusions 2a are arranged at predetermined intervals so that the arrangement density on the facing surface 2s is approximately uniform. The plurality of protrusions 2a support the wafer W at their tips. The protrusion height of the protrusions 2a is, for example, 5 μm or more and 100 μm or less.

[0017] The first gas holes 31 penetrate the dielectric substrate 11 in the thickness direction Z. The first gas holes 31 are circular in plan view. In this embodiment, the first gas holes 31 extend linearly in the thickness direction Z of the dielectric substrate 11. In addition, the first gas holes 31 in this embodiment extend in the vertical direction with a uniform cross-sectional shape. However, the first gas holes 31 may have a bent path inside the dielectric substrate 11 as long as they open upward on the opposing surface 2s.

[0018] The electrostatic attraction electrode 13 is disposed inside the dielectric substrate 11. The electrostatic attraction electrode 13 extends in a plate shape along the opposing surface 2s of the dielectric substrate 11. When a voltage is applied to the electrostatic attraction electrode 13, it generates an electrostatic attraction force that holds the wafer W on the dielectric substrate 11.

[0019] The electrostatic attraction electrode 13 is formed in a layer shape inside the dielectric substrate 11. The thickness of the electrostatic attraction electrode 13 is, for example, 10 μm to 50 μm. The electrostatic attraction electrode 13 is a composite of an insulating material and a conductive material. The insulating material contained in the electrostatic attraction electrode 13 is not particularly limited, but is preferably at least one selected from the group consisting of aluminum oxide (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), yttrium (III) oxide (Y2O3), yttrium aluminum garnet (YAG), and SmAlO3.

[0020] The electrostatic attraction electrode 13 is provided with an evacuation hole 13h that surrounds the periphery of the first gas hole 31. A part of the dielectric substrate 11 is disposed inside the evacuation hole 13h. Therefore, the electrostatic attraction electrode 13 is not exposed from the inner circumferential surface of the first gas hole 31.

[0021] A power supply terminal 16 for applying a DC voltage to the electrostatic attraction electrode 13 is connected to the electrostatic attraction electrode 13. The power supply terminal 16 extends downward from the electrostatic attraction electrode 13. The power supply terminal 16 is inserted into a terminal through-hole 17 that penetrates the base 3 and a portion of the dielectric substrate 11 in the thickness direction Z. The power supply terminal 16 is disposed inside 15 of a cylindrical terminal insulator 23 that has insulating properties. The terminal insulator 23 insulates the base 3, which is made of a conductive material, from the power supply terminal 16.

[0022] The power supply terminals 16 are connected to an external power supply 21. The power supply 21 applies a voltage to the electrostatic attraction electrode 13. The number, shape, etc. of the power supply terminals 16 are determined depending on the type of the electrostatic attraction electrode 13, i.e., whether it is a monopolar type or a bipolar type.

[0023] The base 3 supports the electrostatic chuck member 2 from below. The base 3 has a support surface 3a facing upward. The support surface 3a faces the back surface 2p of the dielectric substrate 11 in the vertical direction. The base 3 supports the back surface 2p of the dielectric substrate 11 on the support surface 3a.

[0024] The base 3 is a disc-shaped conductive member in a plan view. The material constituting the base 3 is not particularly limited as long as it is a metal with excellent thermal conductivity, electrical conductivity, and workability, or a composite material containing such a metal. Suitable materials for the base 3 include alloys such as aluminum (Al), copper (Cu), stainless steel (SUS), and titanium (Ti). Aluminum alloys are preferred as the material constituting the base 3 from the viewpoints of thermal conductivity, electrical conductivity, and workability. At least the surface of the base 3 exposed to plasma is preferably anodized or coated with a polyimide resin. The base 3's frame also functions as an internal electrode for generating plasma. The base 3's frame is connected to an external high-frequency power source 22 via a matching box (not shown).

[0025] The base 3 is fixed to the electrostatic chuck member 2 by an adhesive 55. The adhesive 55 is interposed between the back surface 2p of the electrostatic chuck member 2 and the support surface 3a of the base 3, and bonds and integrates the electrostatic chuck member 2 and the base 3. A heater embedded in the adhesive 55 may be disposed between the back surface 2p and the support surface 3a.

[0026] A plurality of second gas holes 32 are provided in the base 3. The second gas holes 32 penetrate the base 3 in the thickness direction Z. The upper ends of the second gas holes 32 are connected to the first gas holes 31 provided in the dielectric substrate 11. A cylindrical insulator 24 is inserted into the second gas holes 32. The outer peripheral surface of the insulator 24 is fixed to the inner peripheral surface of the second gas hole 32 by, for example, an adhesive.

[0027] The first gas holes 31 and the second gas holes 32 communicate with each other to form a gas supply path 30. The gas supply path 30 opens to the facing surface 2s. The gas supply path 30 is connected to a gas supply device (not shown). The gas supply path 30 supplies a cooling gas G such as helium (He) to the gas supply path 30. The cooling gas G supplied to the gas supply path 30 flows out from the openings 31a of the first gas holes 31 toward the wafer W, and flows through the gas flow space A between the facing surface 2s and the wafer W to cool the wafer W.

[0028] The porous body 40 is inserted into the first gas hole 31 from above. The porous body 40 may be adhesively fixed to the inner circumferential surface of the first gas hole 31. The porous body 40 of this embodiment has a cylindrical shape extending in the thickness direction Z of the dielectric substrate 11.

[0029] The porous body 40 is made of an insulating material. For example, the porous body 40 is made of a thermally sprayed film or porous ceramic. The porous body 40 of this embodiment is made of aluminum oxide (Al2O3).

[0030] A large number of pores are provided inside the porous body 40. The large number of pores inside the porous body 40 are connected to each other. Therefore, the porous body 40 allows the cooling gas G to pass through the first gas holes 31.

[0031] According to this embodiment, the first gas holes 31 are blocked by the porous body 40. This makes it possible to suppress the acceleration of charged particles inside the gas supply path 30, and to prevent the kinetic energy of the charged particles from becoming too high. As a result, it is possible to suppress ionization due to collisions between the charged particles and molecules (e.g., helium) that constitute the cooling gas. According to this embodiment, it is possible to suppress the occurrence of abnormal discharge in the electrostatic chuck device 1, and it is possible to provide a highly reliable electrostatic chuck device 1.

[0032] The pore size (diameter of the pores) of the porous body 40 is not particularly limited as long as it can sufficiently supply the cooling gas G to the opposing surface 2s and suppress abnormal discharge. The pore size of the porous body 40 may be, for example, 30 μm or more and 150 μm or less. If the pore size of the porous body 40 is too small, the cooling gas G cannot be sufficiently supplied to the opposing surface 2s, and if the pore size is too large, the potential change near the upper ends of the first gas holes 31 is large and the generated electric field is also large, which may make it difficult to suppress abnormal discharge.

[0033] The porosity of the porous body 40 is not particularly limited as long as it can supply a sufficient amount of cooling gas G to the opposing surface 2s, and may be, for example, 30% or more and 70% or less. Here, "porosity" refers to the proportion of the total volume of pores in a given unit volume of the porous body 40. The porosity may be a value determined from the ratio of the true density of the material forming the porous body 40 to the apparent density of the porous body 40, or may be determined by actually measuring the volume of pores per unit volume. The higher the porosity of the porous body 40, the more pores there are and the easier it is for the cooling gas G to flow out.

[0034] The upper part of the porous body 40 may be covered with a plate-shaped cap member. The cap member is made of, for example, a ceramic material. The cap member has, for example, a plurality of through-holes with a diameter sufficiently large compared to the pores of the porous body 40. The cap member protects the porous body 40 from plasma during processing of the wafer W. Furthermore, the cooling gas blown out from the porous body 40 passes through the through-holes of the cap member and flows into the gas flow space A.

[0035] FIG. 2 is a partial cross-sectional schematic view of the electrostatic chuck member 2 in the vicinity of the first gas hole 31. As shown in FIG. 2, the dimension of the porous body 40 in the thickness direction Z in this embodiment is greater than the thickness of the dielectric substrate 11. The porous body 40 protrudes upward relative to the facing surface 2s. The protruding height h of the porous body 40 relative to the facing surface 2s is smaller than the protruding height d1 of the protrusions 2a relative to the facing surface 2s. This prevents the porous body 40 from coming into contact with the wafer W supported by the tips of the protrusions 2a. The protruding height h of the porous body 40 relative to the facing surface 2s is, for example, 2 μm or more and 60 μm or less, and can be selected appropriately depending on the value of the protruding height d1 of the protrusions 2a relative to the facing surface 2s.

[0036] In the electrostatic chuck member 2 of this embodiment, the porous body 40 is inserted into the first gas hole 31 to suppress the occurrence of a discharge phenomenon inside the gas supply path 30. However, by inserting the porous body 40 into the first gas hole 31, the porous body 40 obstructs the flow of the cooling gas G in the gas supply path 30, reducing the flow rate of the cooling gas G supplied to the gas flow space A between the wafer W and the facing surface 2s, and thus reducing the cooling effect of the cooling gas G on the wafer W.

[0037] According to this embodiment, the porous body 40 protrudes upward from the opposing surface 2s. Therefore, a large exposed portion 41 is secured on the outer surface of the porous body 40, the exposed portion 41 being exposed from the opening 31a of the first gas hole 31. That is, in this embodiment, the outer surface area S2 of the exposed portion 41 is larger than the opening area S1 of the first gas hole 31 (S2>S1).

[0038] Here, the "external surface area" of the porous body 40 refers to the surface area of ​​the external shape of the porous body 40. Because countless pores are open on the surface of the porous body 40, the actual surface area of ​​the porous body 40 is extremely large. In contrast, the external surface area S2 of the porous body 40 refers to the surface area of ​​the solid that forms the external shape of the porous body 40, and is the surface area of ​​the porous body 40 when it is assumed that the porous body 40 does not have pores.

[0039] In this embodiment, the outer shape of the porous body 40 is cylindrical. Therefore, the outer surface area of ​​the porous body 40 is expressed as the surface area of ​​a cylinder. Furthermore, the outer surface area S2 of the exposed portion 41 means the outer surface area of ​​the portion of the porous body 40 that protrudes from the opposing surface 2s. In this embodiment, the outer surface area S2 of the exposed portion 41 is expressed as the sum of the outer surface area of ​​the upper surface 40a of the porous body 40 and the outer surface area of ​​the region of the outer peripheral surface 40b of the porous body 40 that is above the opposing surface 2s.

[0040] The outer surface area of ​​the upper surface 40a of the porous body 40 of this embodiment is larger than the opening area S1 of the first gas holes 31. Therefore, the outer surface area S2 of the exposed portion 41 is larger than the opening area S1 of the first gas holes 31 by the outer surface area of ​​the region of the outer peripheral surface 40b of the porous body 40 that is above the opposing surface 2s.

[0041] According to this embodiment, by ensuring that the outer surface area S2 of the exposed portion 41 is larger than the opening area S1 of the first gas holes 31, more pores of the porous body 40 open to the gas flow space A than when the outer surface area and the opening area are equal. This makes it easier for the cooling gas G passing through the pores of the porous body 40 to flow into the gas flow space A, thereby increasing the flow rate of the cooling gas G supplied to the gas flow space A. As a result, the flow rate of the cooling gas flowing through the gas flow space A can be increased, and the cooling efficiency of the wafer W by the cooling gas G can be improved.

[0042] Furthermore, according to this embodiment, the outer surface area S2 of the exposed portion 41 is larger than the opening area S1 of the first gas hole 31, so that the outer surface of the exposed portion 41 is wide and can be oriented in various directions in the gas flow space A, which makes it easier to increase the amount of cooling gas G flowing into the gas flow space A.

[0043] In particular, according to this embodiment, the exposed portion 41 protrudes in the thickness direction Z of the dielectric substrate 11 relative to the opposing surface 2s. Therefore, the porous body 40 allows the cooling gas G to flow into the gas flow space A not only from the upper surface 40a but also from a region of the outer peripheral surface 40b of the porous body 40 that is located above the opposing surface 2s. The upper surface 40a of the porous body 40 faces the underside of the wafer W via a very narrow gap (e.g., approximately 10 μm). Therefore, the pressure of the cooling gas tends to increase above the upper surface 40a, making it difficult for the cooling gas G to flow into the gas flow space A through the pores of the porous body 40. On the other hand, the outer peripheral surface 40b of the porous body 40 faces in a direction perpendicular to the thickness direction Z. Therefore, the cooling gas G flowing out from the outer peripheral surface 40b of the porous body 40 into the gas flow space A tends to flow smoothly along the opposing surface 2s, making it easy to increase the flow rate. According to this embodiment, a portion of the outer peripheral surface 40b of the porous body 40 is exposed to the gas flow space A, which makes it easier for the cooling gas G to flow into the gas flow space A through the pores of the porous body 40. According to this embodiment, it is easier to further increase the flow rate of the cooling gas G flowing into the gas flow space A, thereby improving the cooling effect of the cooling gas G on the wafer W.

[0044] In this embodiment, the outer surface area S2 of the exposed portion 41 is preferably 20% or more larger than the opening area S1 of the first gas holes 31 (S2 > S1 × 1.2). In this case, the outer surface area S2 of the exposed portion 41 can be ensured to be sufficiently larger than the opening area S1 of the first gas holes 31, making it easier for the cooling gas G passing through the first gas holes 31 to flow sufficiently from the exposed portion 41 into the gas flow space A.

[0045] The outer surface area S2 of the exposed portion 41 is preferably larger than the flow path cross-sectional area of ​​at least a portion of the first gas hole 31. This makes it easier for the cooling gas G flowing through the first gas hole 31 to flow into the gas flow space A. In this specification, the "flow path cross-sectional area" of the first gas hole 31 means the cross-sectional area of ​​the first gas hole 31 in a cross section perpendicular to the extension direction of the first gas hole 31. In this embodiment, the first gas hole 31 has a uniform flow path cross-sectional area and extends in the thickness direction Z. Therefore, the first gas hole 31 can be easily formed by machining such as drilling.

[0046] <Modification> Next, a description will be given of the porous body and its surrounding structure in several modified examples that can be employed in the above-described embodiment. In the description of each modified example below, the same components as those in the already described embodiment and modified examples will be assigned the same reference numerals, and the description thereof will be omitted.

[0047] (Variation 1) 3 is a partial cross-sectional schematic view of an electrostatic chuck member 102 of Modification 1. The electrostatic chuck member 102 of this modification differs from the above-described embodiment mainly in the shape of the upper surface 140a of the porous body 140.

[0048] The upper end position of the porous body 140 in this modified example is located on the same plane as the opposing surface 2s. Therefore, the exposed portion 141 of the outer shape of the porous body 140 that is exposed from the opening 31a of the first gas hole 31 is provided only on the upper surface 140a of the porous body 140. Furthermore, the upper surface 140a of the porous body 140 in this modified example has a recessed portion 142 that is recessed in the thickness direction Z of the dielectric substrate 11. The recessed portion 142 in this modified example has a mortar shape with its lowest point in the center. However, the shape of the recessed portion is not limited to this modified example. The depth d2 of the recessed portion 142 in the thickness direction Z is, for example, 2 μm or more and 400 μm or less.

[0049] In the porous body 140 of this modification, the recessed portions 142 are provided in the exposed portions 141, so that the outer surface area S12 is larger than that in the case of a flat surface. That is, in this modification, the outer surface area S12 of the exposed portions 141 is larger than the opening area S1 of the first gas holes 31.

[0050] According to this modification, by ensuring that the outer surface area S12 of the exposed portion 141 is larger than the opening area S1 of the first gas holes 31, more pores of the porous body 140 can be opened to the gas flow space A. This increases the flow rate of the cooling gas G supplied to the gas flow space A, thereby improving the cooling efficiency of the wafer W by the cooling gas G.

[0051] In particular, according to this modification, at least a portion of the exposed portion 141 is located below the facing surface 2s. This makes it easier to ensure a distance between the exposed portion 141 and the underside of the wafer W, and prevents the pressure of the cooling gas G from increasing in the space between the porous body 140 and the wafer W. According to this modification, the cooling gas G is more likely to flow into the gas flow space A from the upper surface 140a of the porous body 140, and the cooling effect of the cooling gas G on the wafer W can be improved. Furthermore, according to this modification, it is easier to prevent contact between the porous body 140 and the wafer W, compared to when the porous body 140 protrudes above the facing surface 2s.

[0052] In this modification, the depth d2 of the recessed portion 142 in the thickness direction Z is greater than the protruding height d1 of the protrusion 2a (d2>d1). According to this modification, by making the recessed portion 142 sufficiently deep, a large outer surface area S12 can be ensured. Furthermore, according to this modification, by making the depth d2 of the recessed portion 142 greater than the protruding height d1 of the protrusion 2a, the maximum distance between the exposed portion 141 and the wafer W can be made more than twice the protruding height d1 of the protrusion 2a. This further facilitates the flow of the cooling gas G from the pores of the porous body 140 into the gas flow space A.

[0053] In this modification, the outer surface area S12 of the exposed portion 141 is preferably 20% or more larger than the opening area S1 of the first gas hole 31 (S12>S1×1.2). In this case, the outer surface area S12 of the exposed portion 141 can be ensured to be sufficiently large, which makes it easier to improve the cooling efficiency of the cooling gas G.

[0054] The upper end position of the porous body 140 may be higher than the opposing surface 2s. That is, the porous body 140 may protrude from the opposing surface 2s, and a recessed portion 142 may be provided on the upper surface 140a. In this modification, the upper end position of the porous body 140 may be lower than the opposing surface 2s. That is, the porous body 140 may be disposed at a position recessed from the opposing surface 2s, and a recessed portion 142 may be provided on the bottom surface of the recessed position.

[0055] (Variation 2) 4 is a partial cross-sectional schematic view of an electrostatic chuck member 202 of Modification 2. The electrostatic chuck member 202 of this modification differs from the above-described embodiment mainly in the shape of the upper surface 240a of the porous body 240.

[0056] The porous body 240 of this modified example protrudes upward from the opposing surface 2s, as in the above-described embodiment. The exposed portion 241 of the porous body 240 of this modified example is provided on the upper surface 240a of the porous body 240. Furthermore, the upper surface 240a of the porous body 240 of this modified example has a convex shape that rises upward in a dome shape.

[0057] In this modification, as in the above embodiment, the exposed portions 241 of the outer shape of the porous body 240 that are exposed from the openings 31a of the first gas holes 31 can be ensured to be larger than the opening area of ​​the first gas holes 31, thereby improving the cooling efficiency of the wafer W by the cooling gas G. In this modification, as in the above embodiment, the outer surface area of ​​the exposed portions 241 is larger than the opening area of ​​the first gas holes 31. Furthermore, in this modification, the outer surface area of ​​the exposed portions 241 is preferably larger than the opening area of ​​the first gas holes 31 by 20% or more.

[0058] In this modified example, if the upper surface of the porous body 240 has a convex shape that rises upward, the upper end position of the porous body 240 may be coincident with the opposing surface 2s in the thickness direction Z, or may be lower than the opposing surface 2s.

[0059] (Variation 3) 5 is a partial cross-sectional schematic view of an electrostatic chuck member 302 of Modification 3. The electrostatic chuck member 302 of this modification differs from the above-described embodiment mainly in the shape of the upper surface 340a of the porous body 340 and the shape of the first gas holes 331.

[0060] The upper end position of the porous body 340 of this modified example is located on the same plane as the opposing surface 2s. Furthermore, of the outer shape of the porous body 340, an exposed portion 341 exposed from the opening 331a of the first gas hole 331 is provided on the upper surface 340a of the porous body 340.

[0061] In this modification, the upper surface 340a of the porous body 340 is provided with a recessed portion 342 that is recessed downward, as in the above-described modification 1. That is, the exposed portion 341 of the porous body 340 of this modification is provided with the recessed portion 342 that is recessed in the thickness direction Z of the dielectric substrate 11. Therefore, the outer surface area S32 of the exposed portion 341 is larger than the opening area S31 of the first gas hole 331.

[0062] According to this modification, by ensuring that the outer surface area S32 of the exposed portion 341 is larger than the opening area S31 of the first gas holes 331, more pores of the porous body 340 open to the gas flow space A. This increases the flow rate of the cooling gas G supplied to the gas flow space A, thereby improving the cooling efficiency of the wafer W by the cooling gas G. In this modification, the outer surface area S32 of the exposed portion 341 is preferably larger than the opening area S31 of the first gas holes 331 by 20% or more.

[0063] The dielectric substrate 11 of this modification is provided with first gas holes 331 into which porous bodies 340 are inserted. The first gas holes 331 of this modification have a flow path cross-sectional area that continuously increases toward the upper side. That is, the inner circumferential surface of the first gas holes 331 is tapered so that the inner diameter of the lower end portion becomes smaller.

[0064] In this modification, the cross-sectional area of ​​the first gas hole 331 increases toward the opening 331a in the thickness direction Z of the dielectric substrate 11. Therefore, the cross-sectional area of ​​the first gas hole 331 in this modification is smallest at the lower end. In this modification, the outer peripheral surface 340b of the porous body 340 inserted into the first gas hole 331 is tapered so that the inner diameter becomes smaller at the lower end, similar to the inner peripheral surface of the first gas hole 331.

[0065] The outer surface area S32 of the exposed portion 341 in this modification is larger than the flow path cross-sectional area of ​​at least a portion (lower end) of the first gas hole 331. This makes it easier for the cooling gas G flowing through the first gas hole 331 to flow into the gas flow space A. In particular, according to this modification, the exposed portion 341 is located below the opposing surface 2s. This makes it easier to ensure a distance between the exposed portion 341 and the underside of the wafer W. As a result, the cooling gas G can more easily flow into the gas flow space A through the pores of the porous body 340, thereby improving the cooling effect of the cooling gas G on the wafer W.

[0066] (Variation 4) 6 is a partial cross-sectional schematic view of an electrostatic chuck member 402 of Modification 4. The electrostatic chuck member 402 of this modification differs from the above-described embodiment mainly in the shape of the upper surface 440a of the porous body 440 and the shape of the first gas holes 331.

[0067] In this modification, the upper end position of the porous body 440 of this modification protrudes upward relative to the opposing surface 2s. This ensures that the exposed portion 441 of the porous body 440, which is exposed from the openings 331a of the first gas holes 331, is wide. In this modification, the outer surface area S42 of the exposed portion 441 is larger than the opening area S31 of the first gas holes 331. According to this modification, by ensuring a wide outer surface area S42 of the exposed portion 441, more pores of the porous body 440 open to the gas flow space A. This increases the flow rate of the cooling gas G supplied to the gas flow space A, thereby improving the cooling efficiency of the wafer W by the cooling gas G. In this modification, the outer surface area S42 of the exposed portion 441 is preferably 20% or more larger than the opening area S31 of the first gas holes 331.

[0068] The dielectric substrate 11 of this modification is provided with first gas holes 331 into which a porous body 440 is inserted. Similar to the third modification, the first gas holes 331 of this modification have a flow path cross-sectional area that increases toward the opening 331a in the thickness direction Z of the dielectric substrate 11. The first gas holes 331 have a flow path cross-sectional area that is smallest at the lower end. According to the first gas holes 331 of this modification, the opening area S31 on the opposing surface 2s is larger than the flow path cross-sectional area of ​​at least a portion of the first gas holes 331. This makes it easier for the cooling gas G flowing through the first gas holes 331 to flow into the gas flow space A. Note that in this modification, the outer peripheral surface 440b of the porous body 440 inserted into the first gas holes 331 is tapered along the inner peripheral surface of the first gas holes 331, similar to the third modification.

[0069] According to this modification, the exposed portion 441 protrudes upward from the facing surface 2s. Therefore, not only the upper surface 440a but also the outer peripheral surface 440b of the porous body 440 is exposed to the gas flow space A. Therefore, the porous body 440 allows the cooling gas G to flow into the gas flow space A not only from the upper surface 440a but also from the region of the outer peripheral surface 440b of the porous body 440 that protrudes from the facing surface 2s. This increases the flow rate of the cooling gas G flowing into the gas flow space A, thereby improving the cooling effect of the cooling gas G on the wafer W.

[0070] (Variation 5) 7 is a partial cross-sectional schematic view of an electrostatic chuck member 502 of Modification 5. The electrostatic chuck member 502 of this modification differs from the above-described embodiment mainly in the shape of the upper surface 540a of the porous body 540 and the shape of the first gas holes 531.

[0071] In this modification, the upper end position of the porous body 540 of this modification is located on the same plane as the opposing surface 2s. Furthermore, an exposed portion 541 of the outer shape of the porous body 540, which is exposed from the opening 531a of the first gas hole 531, is provided on the upper surface 540a of the porous body 540. As in the above-described modification 1, a recessed portion 542 recessed downward is provided on the upper surface 540a of the porous body 540 of this modification. That is, the exposed portion 541 of the porous body 540 of this modification is provided with a recessed portion 542 recessed in the thickness direction Z of the dielectric substrate 11. As a result, the outer surface area S52 of the exposed portion 541 is larger than the opening area S51 of the first gas hole 531.

[0072] According to this modification, by ensuring that the outer surface area S52 of the exposed portion 541 is larger than the opening area S51 of the first gas holes 531, more pores of the porous body 540 open to the gas flow space A. This increases the flow rate of the cooling gas G supplied to the gas flow space A, thereby improving the cooling efficiency of the wafer W by the cooling gas G. In this modification, the outer surface area S52 of the exposed portion 541 is preferably larger than the opening area S51 of the first gas holes 531 by 20% or more.

[0073] The dielectric substrate 11 of this modified example is provided with a first gas hole 531 into which a porous body 540 is inserted. The first gas hole 531 of this modified example has a small diameter portion 531c and a large diameter portion 531b. The small diameter portion 531c and the large diameter portion 531b are circular when viewed in the thickness direction Z of the dielectric substrate 11. The small diameter portion 531c and the large diameter portion 531b are connected to each other. The large diameter portion 531b is located above the small diameter portion 531c. The diameter of the large diameter portion 531b is larger than the diameter of the small diameter portion 531c. The upper end of the large diameter portion 531b opens as an opening 531a on the opposing surface 2s. That is, the flow path cross-sectional area of ​​the first gas hole 531 increases toward the opening 531a in the thickness direction Z of the dielectric substrate 11.

[0074] In this modification, the cross-sectional area of ​​the flow path of the first gas hole 531 is smallest at the lower end. In this modification, the outer peripheral surface 540b of the porous body 540 inserted into the first gas hole 531 has a stepped shape having a small diameter portion and a large diameter portion, similar to the inner peripheral surface of the first gas hole 531.

[0075] In this modification, the outer surface area S52 of the exposed portion 541 is larger than the flow path cross-sectional area of ​​at least a portion of the first gas hole 531. This makes it easier for the cooling gas G flowing through the first gas hole 531 to flow into the gas flow space A.

[0076] In this modification, the upper end position of the porous body 540 may be higher than the opposing surface 2s. That is, the porous body 540 may protrude from the opposing surface 2s, and a recessed portion 542 may be provided on the upper surface 540a. In this modification, the upper end position of the porous body 540 may be lower than the opposing surface 2s. That is, the porous body 540 may be disposed at a position recessed from the opposing surface 2s, and a recessed portion 542 may be provided on the bottom surface of the recessed position.

[0077] While various embodiments and modifications of the present invention have been described above, the configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments.

[0078] For example, as a combination of the embodiment and its modified examples, the porous body may protrude from the opposing surface of the dielectric substrate, and the upper surface of the porous body may be recessed. In this case, the inner circumferential surface of the first gas hole may be inclined in a direction that increases the cross-sectional area of ​​the flow path toward the opening. [Explanation of symbols]

[0079] 1...electrostatic chuck device, 2,102,202,302,402,502...electrostatic chuck member, 2a...protrusion, 2s...opposing surface, 3...base, 11...dielectric substrate, 13...electrostatic attraction electrode, 31...first gas hole (gas hole), 31a, 331a, 531a...opening, 40,140,240,340,440,540...porous body, 41,141,241,341,441,541...exposed portion, 142,342,542...concave portion, d1,h...protrusion height, d2...depth, S1,S31,S51...opening area, S2,S12,S32,S42,S52...outer surface area, W...wafer (object to be attracted), Z...thickness direction

Claims

1. An electrostatic chuck member that attracts an object to be attracted, a plate-like dielectric substrate having a surface facing the object to be attracted, a plurality of protrusions protruding from the surface and supporting the object at their tips, and gas holes opening in the surface; an electrostatic attraction electrode disposed inside the dielectric substrate; a porous body inserted into the gas hole, an outer surface area of ​​an exposed portion of the outer shape of the porous body that is exposed from the opening of the gas hole is larger than the opening area of ​​the gas hole; Electrostatic chuck member.

2. The outer surface area is 20% or more larger than the opening area. The electrostatic chuck member according to claim 1 .

3. the exposed portion protrudes from the opposing surface in a thickness direction of the dielectric substrate. The electrostatic chuck member of claim 1 .

4. the exposed portion is provided with a recessed portion recessed in a thickness direction of the dielectric substrate, a depth of the recess in the thickness direction is greater than a protrusion height of the protrusion; The electrostatic chuck member according to claim 1 .

5. the gas holes have a flow path cross-sectional area that increases toward the opening in the thickness direction of the dielectric substrate; The electrostatic chuck member according to claim 1 .

6. The electrostatic chuck member according to any one of claims 1 to 5, a base supporting the electrostatic chuck member from the opposite side of the facing surface, Electrostatic chuck device.

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