Electrostatic chuck member and electrostatic chuck device

Abstract

To provide an electrostatic chuck member capable of enhancing a cooling effect, and an electrostatic chuck device.SOLUTION: An electrostatic chuck member that adsorbs an object to be adsorbed, the electrostatic chuck member including a plate-shaped dielectric substrate having a facing surface facing the object to be adsorbed, a plurality of protrusions protruding from the facing surface and supporting the object to be adsorbed at tips of the protrusions, and a gas hole opened in the facing surface, an electrostatic adsorption electrode disposed inside the dielectric substrate, and a porous body inserted into the gas hole, wherein a recess surrounding the gas hole is provided in the facing surface when viewed from a thickness direction of the dielectric substrate.SELECTED DRAWING: Figure 2

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, The electrostatic chuck member has a recess formed in the opposing surface, the recess surrounding the gas hole when viewed in the thickness direction of the dielectric substrate. [2] The electrostatic chuck member according to [1], wherein the distance between the gas hole and the recess as viewed in the thickness direction is smaller than the diameter of the gas hole. [3] An electrostatic chuck member according to [1] or [2], wherein an end of the porous body in the thickness direction that faces the object to be adsorbed is located on the side of the object to be adsorbed relative to the opposing surface, or on the opposite side of the object to be adsorbed relative to the opposing surface. [4] A cylindrical portion extending in the thickness direction along the inner edge of the opening of the gas hole and having the porous body disposed therein, The electrostatic chuck member according to [1] or [2], wherein the cylindrical portion is made of a material different from that of the porous body. [5] The electrostatic chuck member according to [4], wherein the cylindrical portion is a part of the dielectric substrate. [6] An electrostatic chuck member according to [4] or [5], wherein the end of the porous body in the thickness direction facing the object to be adsorbed is located on the side of the object to be adsorbed relative to the opposing surface, or on the opposite side of the object to be adsorbed relative to the opposing surface. [7] The electrostatic chuck member according to any one of [4] to [6], wherein the thickness of the cylindrical portion is smaller than the width of the recess in the radial direction centered on the gas hole. [8] The electrostatic chuck member according to any one of [4] to [7], wherein the thickness of the cylindrical portion is smaller than the diameter of the protrusion. [9] The recess forms a groove surrounding the gas hole, The electrostatic chuck member according to any one of [1] to [8], wherein the width of the groove is greater than the protrusion height of the protrusion.

[10] The recess forms a groove surrounding the gas hole, The electrostatic chuck member according to any one of [1] to [9], wherein the width of the groove is larger than the depth of the groove.

[11] The electrostatic chuck member according to any one of [1] to

[10] , wherein the depth of the recess is greater than the protrusion height of the protrusion.

[12] An electrostatic chuck member according to any one of [1] to

[11] , 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 schematic cross-sectional view showing an electrostatic chuck device according to a first embodiment. [Figure 2] FIG. 2 is a partial cross-sectional schematic view of the electrostatic chuck member of the first 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 the second embodiment. [Figure 6] FIG. 6 is a partial cross-sectional schematic view of an electrostatic chuck member according to a third modification. [Figure 7] FIG. 7 is a partial cross-sectional schematic view of an electrostatic chuck member according to a fourth 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] First Embodiment FIG. 1 is a schematic cross-sectional view showing an electrostatic chuck device 1 according to the first 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, a recess 43 is provided in the opposing surface 2s. In this embodiment, the recess 43 has a circular shape when viewed in the thickness direction Z of the dielectric substrate 11. The first gas hole 31 opens in a bottom surface 43a of the recess 43. Therefore, the recess 43 surrounds the gas hole when viewed in the thickness direction Z.

[0036] The porous body 40 of this embodiment protrudes upward (+Z) from the bottom surface 43a of the recess 43. Therefore, the inner surface of the recess 43 and the outer peripheral surface 40b of the porous body 40 form an annular groove portion 44. The groove portion 44 surrounds the porous body 40 when viewed from the thickness direction Z. In other words, the recess 43 forms the groove portion 44 that surrounds the periphery of the first gas hole 31.

[0037] In this embodiment, the upper end of the porous body 40 is located on the same plane as the facing surface 2s. Therefore, the distance in the thickness direction Z between the upper end of the porous body 40 and the lower surface of the wafer W is equal to the dimension in the thickness direction Z of the gas flow space A between the facing surface 2s and the wafer W (i.e., the protrusion height d1 of the protrusions 2a).

[0038] The upper surface 40a of the porous body 40 faces the lower surface of the wafer W via a very narrow gap (for example, about 10 μm). Therefore, the pressure of the cooling gas G tends to increase above the upper side (+Z) of the upper surface 40a, which may make it difficult for the cooling gas G to flow into the gas flow space A through the pores of the porous body 40.

[0039] According to this embodiment, the opposing surface 2s of the dielectric substrate 11 is provided with recesses 43 surrounding the first gas holes 31 when viewed from the thickness direction Z. This provides a space extending in the thickness direction Z radially outward from the porous body 40, making it easier for the cooling gas G to flow from the upper side of the porous body 40 to the radially outward side of the porous body 40. According to this embodiment, it is possible to suppress an increase in the pressure of the cooling gas G on the upper side of the porous body 40, making it easier for the cooling gas G to flow from the first gas holes 31 to the upper side of the porous body 40. This makes it easier to increase the flow rate of the cooling gas G flowing into the gas flow space A, making it possible to increase the flow velocity of the cooling gas G flowing through the gas flow space A, and as a result, it is possible to improve the cooling effect of the cooling gas G on the wafer W.

[0040] In particular, the porous body 40 of this embodiment protrudes upward relative to the bottom surface 43a of the recess 43, exposing the outer peripheral surface 40b of the porous body 40 inside the recess 43. Therefore, the porous body 40 allows the cooling gas G to flow into the gas flow space A not only from the top surface 40a but also from a region of the outer peripheral surface 40b of the porous body 40 that is above the bottom surface 43a. This 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.

[0041] In this embodiment, the depth d2 of the recess 43 is greater than the protrusion height d1 of the protrusion 2a (d2>d1). With this configuration, the volume inside the groove 44 can be ensured to be sufficiently large relative to the size of the gap between the facing surface 2s and the underside of the wafer W, making it easier to flow the cooling gas G into the groove 44. In this embodiment, the depth d2 of the recess 43 is, for example, not less than 5 μm and not more than 100 μm.

[0042] As described above, the recess 43 forms the groove 44. In this embodiment, the width t2 of the groove 44 is larger than the protrusion height d1 of the protrusion 2a (t2>d1). This configuration ensures that the volume inside the groove 44 is sufficiently large relative to the size of the gap between the facing surface 2s and the lower surface of the wafer W, making it easier for the cooling gas G to flow into the groove 44. The width t2 of the groove 44 is, for example, not less than 50 μm and not more than 1000 μm.

[0043] In this embodiment, the width t2 of the groove 44 is larger than the depth d2 of the groove 44 (t2>d2). This configuration ensures a large width t2 of the groove 44, making it easier to create a flow of the cooling gas G in the groove 44 that is directed away from the first gas holes 31. This allows the cooling gas G to flow smoothly between the facing surface 2s and the underside of the wafer W, making it easier to increase the flow rate of the cooling gas G in the gas flow space A. As a result, the cooling effect of the cooling gas G on the wafer W can be improved.

[0044] <Modification of the first embodiment> Next, a description will be given of the porous body and its surrounding configurations in several modified examples that can be employed in the first embodiment. In the description of each modified example below, the same components as those in the already described embodiments and modified examples will be assigned the same reference numerals, and the description thereof will be omitted.

[0045] (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 first embodiment mainly in the position of the upper end 140a of the porous body 140.

[0046] In this modification, the upper end 140a of the porous body 140 is located above (+Z) the opposing surface 2s. That is, the end of the porous body 140 on the wafer W side in the thickness direction Z is located closer to the wafer W than the opposing surface 2s. According to this modification, a wider region of the outer peripheral surface 140b of the porous body 140 located above the bottom surface 43a can be secured. This makes it easier to increase the flow rate of the cooling gas G flowing from the porous body 140 into the gas flow space A, thereby improving the cooling effect of the cooling gas G on the wafer W. Furthermore, according to this modification, a larger dimension in the thickness direction Z of the porous body 140 can be secured, making it easier to improve the effect of the porous body 140 in suppressing abnormal discharge.

[0047] (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 that of the first embodiment mainly in the position of the upper end of the porous body 240.

[0048] In this modification, the upper end of the porous body 240 is located below (-Z) the facing surface 2s. That is, the end of the porous body 240 on the wafer W side in the thickness direction Z is located on the opposite side of the facing surface 2s from the wafer W. According to this modification, it is easy to ensure a distance between the upper surface 240a of the porous body 240 and the lower surface of the wafer W, and it is possible to suppress an increase in the pressure of the cooling gas G below the wafer W. This makes it easier for the cooling gas G to flow into the gas flow space A through the pores of the porous body 240, and it is possible to enhance the cooling effect of the cooling gas G on the wafer W. Furthermore, according to this modification, it is easier to suppress contact between the porous body 240 and the wafer W compared to when the porous body protrudes above (+Z) the facing surface.

[0049] Second Embodiment 5 is a partial cross-sectional schematic view of an electrostatic chuck member 302 according to the second embodiment. The electrostatic chuck member 302 according to the second embodiment differs from the above-described embodiments in that the dielectric substrate 311 has a cylindrical portion 319. The same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0050] As shown in FIG. 3 , a groove (recess) 344 is provided on the opposing surface 2s of the dielectric substrate 311. In this embodiment, the groove 344 is annular. The groove 344 surrounds the porous body 40 as viewed in the thickness direction Z. According to this embodiment, the opposing surface 2s of the dielectric substrate 311 is provided with the groove 344 surrounding the first gas hole 31 as viewed in the thickness direction Z. A space extending in the thickness direction Z is provided radially outward of the porous body 40, facilitating the flow of the cooling gas G from the upper side of the porous body 40 to the radially outer side of the porous body 40. As a result, an increase in the pressure of the cooling gas G on the upper side of the porous body 40 can be suppressed, and the cooling gas G can easily flow from the first gas hole 31 to the upper side of the porous body 40. According to this embodiment, the flow rate of the cooling gas G flowing into the gas flow space A can be further increased, thereby enhancing the cooling effect of the cooling gas G on the wafer W.

[0051] The porous body 40 in this embodiment protrudes upward (+Z) from the bottom surface 344a of the groove portion 344. In this embodiment, the upper end of the porous body 40 is located on the same plane as the facing surface 2s. Therefore, the distance in the thickness direction Z between the upper end of the porous body 40 and the lower surface of the wafer W is equal to the dimension in the thickness direction Z of the gas flow space A between the facing surface 2s and the wafer W (i.e., the protrusion height d1 of the protrusion 2a).

[0052] The dielectric substrate 311 has a cylindrical portion 319 provided between the groove portion 344 and the first gas hole 31. The cylindrical portion 319 protrudes upward (+Z) from the bottom surface 344a of the groove portion 344. The cylindrical portion 319 extends in the thickness direction Z along the inner edge of the opening portion 31a of the first gas hole 31. The surface of the cylindrical portion 319 facing radially outward constitutes a part of the inner surface of the groove portion 344.

[0053] The porous body 40 is disposed inside the cylindrical portion 319. The inner diameter of the cylindrical portion 319 is equal to the outer diameter of the porous body 40. Therefore, the porous body 40 is fitted onto the inner circumferential surface of the cylindrical portion 319. The porous body 40 may be adhesively fixed to the inner circumferential surface of the cylindrical portion 319.

[0054] According to the present embodiment, the cylindrical portion 319 surrounds the upper end of the porous body 40, thereby protecting the upper end of the porous body 40. This makes it possible to prevent damage or defects from occurring to the porous body 40. In the present embodiment, the upper end of the cylindrical portion 319 and the upper end of the porous body 40 are located on the same plane in the thickness direction Z of the dielectric substrate 311. Therefore, the cylindrical portion 319 of the present embodiment protects the entire porous body 40. However, the upper surface 40a of the porous body 40 may be located above the upper end of the cylindrical portion 319 or below the upper end of the cylindrical portion 319.

[0055] In the present embodiment, the cylindrical portion 319 is a part of the dielectric substrate 311. Therefore, the cylindrical portion 319 is made of a different material from the porous body 40. According to the present embodiment, by selecting a material for the dielectric substrate 311 that is stronger than the porous body 40, the porous body 40 can be appropriately protected. Furthermore, according to the present embodiment, since the cylindrical portion 319 is a part of the dielectric substrate 311, the manufacturing process of the electrostatic chuck member 302 can be simplified and the electrostatic chuck member 302 can be manufactured at low cost, compared to when the cylindrical portion 319 is a separate member from the dielectric substrate 311.

[0056] Note that the cylindrical portion 319 may be a separate member from the dielectric substrate 311, as long as it is made of a material different from that of the porous body 40. In this case, it is preferable to fix the separately prepared cylindrical portion 319 to the dielectric substrate 311 using an adhesive or the like.

[0057] In this embodiment, the thickness d3 of the cylindrical portion 319 is smaller than the diameter D of the first gas hole 31 (d3 < D). Here, the thickness d3 of the cylindrical portion 319 is the distance between the first gas hole 31 and the groove portion 344 as viewed in the thickness direction Z. According to this configuration, since the distance between the first gas hole 31 and the groove portion 344 becomes closer, the cooling gas G supplied from the first gas hole 31 can easily reach the groove portion 344. According to this embodiment, an increase in the pressure of the cooling gas G above the porous body 40 can be suppressed, and the cooling gas G can easily flow into the upper side of the porous body 40 from the first gas hole 31. According to this embodiment, it becomes easier to further increase the flow rate of the cooling gas G flowing into the gas flow space A, and the cooling effect of the wafer W by the cooling gas G can be enhanced.

[0058] In this embodiment, the thickness d3 of the cylindrical portion 319 is smaller than the width dimension t2 of the groove portion 344 in the radial direction centered on the first gas hole 31 (d3 < t2). According to this configuration, since the thickness d3 of the cylindrical portion 319 can be made sufficiently small while the width dimension t2 of the groove portion 344 can be increased, the cooling gas G can easily flow from the upper side (+Z) of the porous body 40 through the cylindrical portion 319 and into the inside of the groove portion 344. As a result, it becomes easier to further increase the flow rate of the cooling gas G flowing into the gas flow space A, and the cooling effect of the wafer W by the cooling gas G can be enhanced.

[0059] In this embodiment, the thickness d3 of the cylindrical portion 319 is smaller than the diameter t1 of the protrusion 2a (d3 < t1). According to this configuration, the thickness d3 of the cylindrical portion 319 can be made sufficiently small, and the cooling gas G above the porous body 40 can easily flow through the cylindrical portion 319 and into the groove portion 344. Thereby, an increase in the pressure of the cooling gas G above the porous body 40 can be suppressed, and it becomes easier to increase the flow rate of the cooling gas G flowing into the gas flow space A. Note that the diameter t1 of the protrusion 2a is, for example, 100 μm or more and 3000 μm or less.

[0060] In this embodiment, the depth d2 of the groove 344 is greater than the protrusion height d1 of the protrusion 2a (d2>d1). With this configuration, the volume inside the groove 344 can be secured to be sufficiently large relative to the size of the gap between the facing surface 2s and the lower surface of the wafer W, and the cooling gas G can be easily introduced into the groove 344.

[0061] In this embodiment, the width t2 of the groove 344 is larger than the protrusion height d1 of the protrusion 2a (t2>d1). With this configuration, the volume of the interior of the groove 344 can be secured to be sufficiently large relative to the size of the gap between the facing surface 2s and the lower surface of the wafer W, and the cooling gas G can be easily introduced into the interior of the groove 344.

[0062] In this embodiment, the width t2 of the groove 344 is larger than the depth d2 of the groove 344 (t2>d2). This configuration ensures a large width t2 of the groove 344, making it easier to create a flow of the cooling gas G in the groove 344 that is directed away from the first gas holes 31. This allows the cooling gas G to flow smoothly between the facing surface 2s and the underside of the wafer W, making it easier to increase the flow rate of the cooling gas G in the gas flow space A. As a result, the cooling effect of the cooling gas G on the wafer W can be improved.

[0063] In the second embodiment, it has been described that the distance between the first gas hole 31 and the groove portion 44 as viewed in the thickness direction Z (i.e., the thickness d3 of the cylindrical portion 319) is smaller than the diameter D of the first gas hole 31. As shown in the first embodiment in FIG. 2 , a structure in which no cylindrical portion is provided around the porous body 40 and the outer circumferential surface 40b of the porous body 40 is exposed to the groove portion 44 can be described as a case in which the distance between the first gas hole 31 and the recessed portion 43 as viewed in the thickness direction Z of the dielectric substrate 11 is zero. That is, in the electrostatic chuck member 2 of the first embodiment, as in the second embodiment, the distance between the first gas hole 31 and the recessed portion 43 as viewed in the thickness direction Z is smaller than the diameter D of the first gas hole 31.

[0064] <Modification of the second embodiment> Next, a description will be given of the porous body and its surrounding structure in several modified examples that can be employed in the second embodiment. In the description of each modified example below, the same components as those in the already described embodiment and modified example will be assigned the same reference numerals, and the description thereof will be omitted.

[0065] (Variation 3) 6 is a partial cross-sectional schematic view of an electrostatic chuck member 402 of Modification 3. The electrostatic chuck member 402 of this modification differs from that of the second embodiment mainly in the position of the upper end of the porous body 140. Also, similar to the second embodiment, the dielectric substrate 311 has a cylindrical portion 319 that surrounds the porous body 140.

[0066] In this modification, the upper end of the porous body 140 is located above (+Z) the opposing surface 2s. That is, the end of the porous body 140 on the wafer W side in the thickness direction Z is located on the wafer W side of the opposing surface 2s. According to this modification, it is possible to ensure a large dimension of the porous body 140 in the thickness direction Z, which makes it easier to improve the effect of the porous body 140 in suppressing abnormal discharge.

[0067] (Variation 4) 7 is a partial cross-sectional schematic view of an electrostatic chuck member 502 of Modification 4. The electrostatic chuck member 502 of this modification differs from that of the second embodiment mainly in the position of the upper end of the porous body 240. Also, similar to the second embodiment, the dielectric substrate 311 has a cylindrical portion 319 that surrounds the porous body 240.

[0068] In this modification, the upper end of the porous body 240 is located below (-Z) the facing surface 2s. That is, the end of the porous body 240 on the wafer W side in the thickness direction Z is located on the opposite side of the facing surface 2s from the wafer W. According to this modification, it is easy to ensure a distance between the upper surface 240a of the porous body 240 and the lower surface of the wafer W, and it is possible to suppress an increase in the pressure of the cooling gas G below the wafer W. This makes it easier for the cooling gas G to flow into the gas flow space A through the pores of the porous body 240, and it is possible to enhance the cooling effect of the cooling gas G on the wafer W. Furthermore, according to this modification, it is easier to suppress contact between the porous body 240 and the wafer W compared to when the porous body protrudes above (+Z) the facing surface.

[0069] In both the third and fourth modified examples described above, the position of the upper end of the porous bodies 140, 240 in the thickness direction Z coincides with the position of the upper end of the cylindrical portion 319. However, the upper ends of the porous bodies 140, 240 may be located above the upper end of the cylindrical portion 319, or may be located below the upper end of the cylindrical portion 319.

[0070] 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. [Explanation of symbols]

[0071] 1...electrostatic chuck device, 2,102,202,302,402,502...electrostatic chuck member, 2a...protrusion, 2s...opposing surface, 3...base, 11,311...dielectric substrate, 13...electrostatic attraction electrode, 31...first gas hole (gas hole), 31a...opening, 40,140,240...porous body, 43...recess, 44,344...groove portion, 319...cylindrical portion, 344...groove portion (recess), D, t1...diameter, d1...protrusion height, d2...depth, d3...thickness, t2...width dimension, 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, a recessed portion surrounding the gas hole when viewed in the thickness direction of the dielectric substrate is provided on the opposing surface; Electrostatic chuck member.

2. a distance between the gas hole and the recess as viewed in the thickness direction is smaller than a diameter of the gas hole; The electrostatic chuck member according to claim 1 .

3. an end portion of the porous body on the side of the object to be adsorbed in the thickness direction is located on the side of the object to be adsorbed with respect to the opposing surface, or on the opposite side of the object to be adsorbed with respect to the opposing surface; The electrostatic chuck member according to claim 1 .

4. a cylindrical portion extending in the thickness direction along an inner edge of an opening of the gas hole and having the porous body disposed therein; The cylindrical portion is made of a material different from the porous body. The electrostatic chuck member according to claim 1 .

5. the cylindrical portion is a part of the dielectric substrate; The electrostatic chuck member according to claim 4 .

6. an end portion of the porous body on the side of the object to be adsorbed in the thickness direction is located on the side of the object to be adsorbed with respect to the opposing surface, or on the opposite side of the object to be adsorbed with respect to the opposing surface; The electrostatic chuck member according to claim 4 .

7. a thickness of the cylindrical portion is smaller than a width of the recess in a radial direction centered on the gas hole; The electrostatic chuck member according to claim 4 .

8. The thickness of the cylindrical portion is smaller than the diameter of the protrusion. The electrostatic chuck member according to claim 4 .

9. the recess forms a groove surrounding the gas hole, The width dimension of the groove is greater than the protrusion height of the protrusion. The electrostatic chuck member according to claim 1 .

10. the recess forms a groove surrounding the gas hole, The width dimension of the groove is greater than the depth dimension of the groove. The electrostatic chuck member according to claim 1 .

11. The depth of the recess is greater than the protrusion height of the protrusion. The electrostatic chuck member according to claim 1 .

12. The electrostatic chuck member according to any one of claims 1 to 11, a base supporting the electrostatic chuck member from the opposite side of the facing surface, Electrostatic chuck device.

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