Electrostatic chuck

Abstract

The present invention provides an electrostatic chuck, according to an embodiment of the present invention, comprising a ceramic plate having a first face and a second face, the ceramic plate comprising: a plurality of ceramic layers; a first electrode and a second electrode disposed between the plurality of ceramic layers; the first through hole and the second through hole penetrate through one part of the ceramic layer, the first through hole is connected with the first electrode, the second through hole is connected with the second electrode, and one end of the first through hole and one end of the second through hole are exposed on the second surface of the ceramic plate; and a conductive silicon pad disposed on the second surface of the ceramic plate and bonded to one end of the first through-hole and one end of the second through-hole to electrically connect the first through-hole and the second through-hole.

Description

TECHNICAL FIELD

[0001] The present application relates to an electrostatic chuck which electrically connects electrodes built in a ceramic plate using conductive silicone. BACKGROUND

[0002] Generally, a semiconductor device or an LCD display device is manufactured by sequentially laminating a plurality of thin film layers including a dielectric layer and an electrode layer on a glass substrate, a flexible substrate, or a semiconductor wafer substrate, and then performing patterning. In order to support the glass substrate, the flexible substrate, the semiconductor wafer substrate, etc. and perform a semiconductor process, a ceramic susceptor (also referred to as a ceramicsusceptor) such as an electrostatic chuck (ESC) or a ceramic heater is used, wherein the electrostatic chuck is mainly used in a process of dry etching a thin film layer formed on a substrate.

[0003] The electrostatic chuck is a structural element for placing a substrate such as a semiconductor wafer inside a vacuum chamber of a semiconductor and LCD manufacturing apparatus, and is a member for fixing a substrate using electrostatic force and heating or cooling the substrate. A representative example of the electrostatic chuck is a ceramic type electrostatic chuck.

[0004] Figure 1 is a sectional view showing a ceramic type electrostatic chuck of the related art, Figure 2 is a bottom view showing a bottom surface of a ceramic plate of the related art.

[0005] Referring to Figure 1 and Figure 2 , the electrostatic chuck 10 is composed of a ceramic plate 12 and a base 14. The base 14 can be formed of a material such as metal or a metal-ceramic composite (Al-SiC, Al-TiC, etc.). The ceramic plate 12 and the base 14 are joined by an adhesive such as silicone resin.

[0006] The ceramic plate 12 is a portion that attracts a semiconductor wafer, etc., and is composed of a plurality of ceramic layers laminated. In the inside of the ceramic plate 12, electrodes 16 such as a chucking electrode, an RF electrode, a heating element layer, etc. are disposed between the ceramic layers. Figure 1 An electrostatic chuck having two layers of chucking electrodes 16 is exemplarily shown in

[0007] The two layers of chucking electrodes 16 are electrically connected by conductive vias 18 and a copper clad laminate (CCL) 20 for bridging the conductive vias 18. The CCL 20 in a film form is composed of a metal layer (for example, copper) 22 and a polyimide layer 24 for electrically insulating the metal layer 22, and serves as an electrical connection member.

[0008] However, since both the CCL 20 and the through-hole 18 are in a solid state having a certain hardness, the CCL 20 and the through-hole 18 can not be closely adhered to each other, resulting in a problem of a slight gap in the contact portion A. At this time, in a process using the electrostatic chuck 10, when the temperature of the ceramic plate 12 rises, a bubble existing in the gap of the contact portion A expands, resulting in a poor contact between the CCL 20 and the through-hole 18. In addition, since the ceramic plate 12 is used in an environment having a large temperature difference of -100°C to 200°C, a poor contact can occur in the contact portion A due to expansion and contraction of the polyimide of the CCL 20.

[0009] Furthermore, due to such a temperature difference, the ceramic plate 12 and the base 14 also expand and contract. At this time, since the ceramic plate 12 and the base 14 formed of different materials have different thermal expansion coefficients, stress can occur due to expansion and contraction. The silicone resin adhesive between the ceramic plate 12 and the base 14 functions to disperse and relieve such stress. However, when the CCL 20 including the metal layer 22 and the polyimide layer 24 exists in the bonding layer of the ceramic plate 12 and the base 14, dispersion of such stress is hindered, resulting in peeling or cracking of the ceramic plate 12. SUMMARY

[0010] PROBLEMS TO BE SOLVED BY THE INVENTION An object of the present invention is to provide an electrical connection member capable of closely adhering to a through-hole.

[0011] In addition, an object of the present invention is to provide an electrical connection member capable of relieving thermal stress between a ceramic plate and a base.

[0012] MEANS FOR SOLVING THE PROBLEMS An embodiment of the present invention provides an electrostatic chuck including a ceramic plate having a first surface and a second surface, the ceramic plate including: a plurality of ceramic layers; a first electrode and a second electrode disposed between the plurality of ceramic layers; a first through-hole and a second through-hole penetrating a portion of the ceramic layers, the first through-hole being connected to the first electrode, the second through-hole being connected to the second electrode, one end of the first through-hole and one end of the second through-hole being exposed to the second surface of the ceramic plate; and a conductive silicone pad disposed on the second surface of the ceramic plate and joined to one end of the first through-hole and one end of the second through-hole to electrically connect the first through-hole and the second through-hole.

[0013] An embodiment of the present invention provides an electrostatic chuck, wherein the conductive silicone pad is formed by applying a liquid conductive silicone.

[0014] An embodiment of the present invention provides an electrostatic chuck, wherein a portion of the conductive silicone is disposed between one end of the first through-hole and the ceramic layer penetrated by the first through-hole.

[0015] An electrostatic chuck according to an embodiment of the present application includes a conductive silicone pad including a conductive filler composed of silver (Ag), nickel (Ni), graphite, or a mixture thereof.

[0016] An electrostatic chuck according to an embodiment of the present application includes a conductive silicone pad having a thickness of 50 μm or more and 150 μm or less.

[0017] An electrostatic chuck according to an embodiment of the present application includes a conductive silicone pad having an elastic modulus of about 10 MPa at 25 °C.

[0018] An electrostatic chuck according to an embodiment of the present application includes a ceramic plate including a cavity formed in a second face of the ceramic plate to a prescribed depth, one end of a first through-hole and one end of a second through-hole being exposed to the cavity, and a conductive silicone pad being disposed in the cavity.

[0019] An electrostatic chuck according to an embodiment of the present application includes a cavity having a depth of 50 μm or more and 150 μm or less.

[0020] An electrostatic chuck according to an embodiment of the present application includes a ceramic plate having a first face and a second face, the ceramic plate including an electrode disposed inside the ceramic plate, a through-hole penetrating a portion of the ceramic plate and connected to the electrode, one end of the through-hole being exposed to the second face of the ceramic plate, and a conductive silicone pad disposed on the second face of the ceramic plate and joined to one end of the through-hole, a portion of the conductive silicone pad being disposed between one end of the through-hole and the ceramic plate penetrated by the through-hole.

[0021] Effects of Invention According to an embodiment of the present application, short-circuiting of electrical connections between electrodes built into a ceramic plate can be prevented.

[0022] Further, according to an embodiment of the present application, thermal stress between a ceramic plate and a base can be alleviated. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 FIG. 1 is a cross-sectional view showing a ceramic-type electrostatic chuck according to the prior art.

[0024] Figure 2 FIG. 3 is a bottom view showing a bottom face of a ceramic plate according to the prior art.

[0025] Figure 3 FIG. 6 is a schematic cross-sectional view of an electrostatic chuck according to an embodiment of the present application.

[0026] Figure 4 FIG. 9 is a cross-sectional view of a ceramic plate according to an embodiment of the present application before a conductive silicone pad is formed.

[0027] Figure 5 is a cross-sectional view of a ceramic board according to an embodiment of the present application before formation of a conductive silicon pad.

[0028] Figure 6 is a cross-sectional view of a ceramic board according to an embodiment of the present application after formation of a conductive silicon pad.

[0029] Figure 7 is a plan view of a ceramic board according to an embodiment of the present application after formation of a conductive silicon pad.

[0030] Figure 8 is a plan view of a ceramic board according to an embodiment of the present application showing a state in which a conductive silicon pad is in close contact with a through hole.

[0031] Figure 9 is a cross-sectional view of a ceramic board according to another embodiment of the present application before formation of a conductive silicon pad.

[0032] Figure 10 is a cross-sectional view of a ceramic board according to another embodiment of the present application after formation of a conductive silicon pad.

[0033] Explanation of Reference Numerals 100: electrostatic chuck 112: ceramic board 114: base 116, 117: electrode 118, 119: through hole 120: conductive silicon pad DETAILED DESCRIPTION Hereinafter, embodiments disclosed in the present specification are explained in detail with reference to the accompanying drawings, but the same or similar constituent elements are assigned the same reference numerals regardless of the drawings, and repeated explanation thereof is omitted. Hereinafter, in the explanation of the embodiments of the present application, when it is written that each layer (film), region, pattern, or structure is formed "on" or "under" a substrate, each layer (film), region, pad, or pattern, "on" and "under" include both "directly" or "indirectly" formed cases.

[0034] Further, the reference of up / upper, down / lower, left / left side, right / right side, vertical (up and down), and horizontal (left and right) of each layer is explained with reference to the drawings. The thickness or size of each layer in the drawings is exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size of each constituent element does not completely reflect the actual size.

[0035] In the present specification, "comprising", "having", "including", or "containing", or the like, does not exclude the presence of one or more other features, numbers, steps, operations, elements, or a part or combination thereof.

[0036] In addition, the terms of first, second, and the like can be used to describe various constituent elements, but the constituent elements are not limited by the terms, and the terms are used only for the purpose of distinguishing one constituent element from another.

[0037] In addition, the term "about" indicates a conventional error range of each value easily known to those skilled in the art, and the term "about" can indicate ±0.5% or at most 1% of the indicated value. In addition, the term "about" can indicate a measurement error due to the limitation of a measurement method.

[0038] In addition, in explaining the embodiments disclosed in the present specification, if it is judged that a detailed description of the related known technology can obscure the gist of the embodiments disclosed in the present specification, the detailed description thereof is omitted.

[0039] The accompanying drawings are merely provided for the convenience of understanding the embodiments disclosed in the present specification, and should not limit the technical idea disclosed in the present specification by the drawings, and it should be understood that all modifications, equivalents, and even alternatives included in the inventive idea and technical scope are included.

[0040] Hereinafter, the embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0041] Figure 3 is a schematic sectional view of an electrostatic chuck according to an embodiment of the present application.

[0042] The electrostatic chuck 100 according to the embodiment of the present application is provided in an apparatus for performing a semiconductor process, for supporting various process object substrates such as a glass substrate, a flexible substrate, and a semiconductor wafer substrate, etc. in a process such as a plasma enhanced chemical vapor deposition, and can also be used as a heater for achieving accurate temperature control and heat treatment requirements in a plasma deposition process, etc. in order to achieve a fine process such as wiring miniaturization of a semiconductor device.

[0043] Referring to Figure 3 The electrostatic chuck 100 according to the embodiment of the present application has a ceramic plate 112 and a base 114. The ceramic plate 112 has a laminated structure of a plurality of ceramic layers 112a, 112b, 112c, a plurality of electrodes 116, 117, through holes 118, 119, and a conductive silicon pad 120.

[0044] The ceramic plate 112 is a member that adsorbs and holds a substrate such as a semiconductor wafer. The ceramic plate 112 has a plate surface (first surface) 113a and a plate back surface (second surface) 113b, and the first surface 113a of the ceramic plate 112 is an adsorption surface that adsorbs a substrate such as a semiconductor wafer. The ceramic plate 112 can be formed into a disc shape having a diameter of about 300 mm and a thickness of about 3 mm by laminating a plurality of ceramic layers 112a, 112b, 112c.

[0045] The ceramic plate 112 is formed of an insulator or dielectric ceramic material, and can be formed of Al2O3, Y2O3, ZrO2, AlC, TiN, AlN, TiC, MgO, CaO, CeO2, TiO2, B x C y , BN, SiO2, SiC, YAG, Mullite, AlF3, or a material in which two or more of these are used in combination.

[0046] The electrodes 116, 117 are arranged inside the ceramic plate 112. The electrodes 116, 117 of the ceramic plate 112 can be chucking electrodes, radio frequency (RF) electrodes, and / or a heater layer. The electrodes 116, 117 can be formed using CVD, PVC, thermal spraying processes, or screen printing processes, etc.

[0047] The chucking electrodes 116, 117 are electrodes that generate an electrostatic force for adsorbing and fixing a substrate by generating an electric field between the electrodes and a substrate such as a semiconductor wafer by a direct current (DC) voltage. The RF electrodes perform an RF grounding function that discharges an electric current charged by plasma inside a chamber to an external grounding terminal during a wafer deposition process. The heater layer performs a function of heating a substrate in an etching process of a thin film layer formed on the substrate or a baking process of a photoresist, etc. In the embodiment of the present application, the electrodes 116, 117 can be chucking electrodes, but the present application is not limited thereto.

[0048] The chucking electrodes 116, 117 can be formed in a structure of two or more layers to more uniformly distribute an electric field and precisely control a fixing force of a semiconductor wafer by voltage adjustment between the electrodes. The electrodes 116, 117 are arranged between the plurality of ceramic layers 112a, 112b, 112c. Each of the electrodes 116, 117 and the ceramic layers 112a, 112b, 112c can be alternately laminated layer by layer. In other words, they can be laminated in the order of a first ceramic layer 112a, a first electrode 116, a second ceramic layer 112b, a second electrode 117, and a third ceramic layer 112c.

[0049] The first electrode 116 and the second electrode 117 are disposed on different planes within the ceramic plate 112. Specifically, the first electrode 116 may be disposed on the plane between the first ceramic layer 112a and the second ceramic layer 112b, and the second electrode 117 may be disposed on the plane between the second ceramic layer 112b and the third ceramic layer 112c. Electrodes 116 and 117 may be formed of tungsten (W), molybdenum (Mo), silver (Ag), gold (Au), niobium (Nb), titanium (Ti), or alloys thereof. The electrode layers 116 and 117 embedded in the ceramic plate 112 receive current supply through electrode rods 128 disposed within the base 114.

[0050] The first electrode 116 and the second electrode 117 are electrically connected through conductive vias 118 and 119. The conductive vias 118 and 119 may be cylindrical with one end and the other end. The first via 118 and the second via 119 penetrate a portion of ceramic layers 112a, 112b, and 112c and are connected to the first electrode 116 and the second electrode 117. The first via 118 vertically penetrates the second ceramic layer 112b and the third ceramic layer 112c, with one end connected to the lower surface of the first electrode 116. The second via 119 vertically penetrates the third ceramic layer 112c at a different location than the first via 118, with one end connected to the lower surface of the second electrode 117. The other ends of the first via 118 and the second via 119 are connected to a conductive silicon pad 120 on the second surface 112b of the ceramic plate. The vias 118 and 119 and the conductive silicon pad 120 will be described in detail below.

[0051] A base 114 is attached to the second surface 113b of the ceramic plate. The base 114 is a component made of metal or metal-ceramic composite material (Al-SiC, Al-TiC, etc.) formed in a disc shape, such as aluminum or aluminum alloy. The base 114 can be formed as a multi-layer structure consisting of multiple metal layers or multiple metal-ceramic composite layers. These metal layers or metal-ceramic composite layers can be joined by processes such as brazing, welding, or bonding. The base 114 can be formed in the shape of a disc with a diameter of 340 mm and a thickness of 32 mm.

[0052] An adhesive layer 124 is disposed between the ceramic plate 112 and the base 114 to bond the ceramic plate 112 to the base 114. The adhesive layer 124 may be made of an adhesive made of silicone resin. In this case, a conductive silicone pad 120 is embedded in the adhesive layer 124, and the conductive silicone pad 120 is electrically insulated from the metal base 114 through the adhesive layer 124. Alternatively, the ceramic plate 112 may be fixed to the base 114 using a pre-defined fixing unit. The base 114 and the ceramic plate 112 may be manufactured separately and then joined together, or the structure of the ceramic plate 112 may be formed directly on the upper surface of the base 114.

[0053] Figure 4 This is a cross-sectional view of a ceramic plate according to an embodiment of the present invention before the formation of the conductive silicon pad. Figure 5 This is a bottom view of a ceramic plate according to an embodiment of the present invention before the formation of the conductive silicon pad.

[0054] Reference Figure 4 and Figure 5 One end of the first through hole 118 is connected to the lower surface of the first electrode 116, and one end of the second through hole 119 is connected to the lower surface of the second electrode 117. The other ends 118a of the first through hole and 119a of the second through hole are exposed to the second surface 113b of the ceramic plate. In embodiments of the present invention, the term "exposed" does not only mean that a specific component is exposed to the atmosphere outside the electrostatic chuck, but also includes situations where a specific component is exposed in a manner that can be observed from the outside, and then covered, coated, or layered by other components and cannot be observed. The ceramic plate 112 according to an embodiment of the present invention will be described in detail below.

[0055] The ceramic plate 112 is manufactured by sintering multiple ceramic layers 112a, 112b, and 112c. At this time, electrodes 116 and 117 are formed on the surface of a portion of the ceramic layers 112a, 112b, and 112c, thereby forming a stacked structure.

[0056] To form conductive vias 118 and 119 for electrical connections between the stacked electrodes 116 and 117, holes are formed along a direction perpendicular to the electrodes 116 and 117. The holes extend from the second surface 113b of the ceramic plate through the third ceramic layer 112c and / or the second ceramic layer 112b, exposing the lower surfaces of the first electrode 116 and the second electrode 117. The holes can be formed using processes such as drilling, bead blasting, and etching.

[0057] To form conductive vias 118 and 119, the interior of the vias can be filled with a conductive material using conductive metal paste, physical vapor deposition (PVD), chemical vapor deposition (CVD), brazing, or other metal deposition methods. After being filled with the conductive material, one end 118a and 119a of the first and second vias are exposed on the second surface 113b of the ceramic plate and can be electrically connected via a conductive silicon pad 120 as described below. At this time, one end 118a and 119a of the first and second vias can be exposed by lapping the second surface 113b of the ceramic plate. (Refer to...) Figure 5 It can be seen that one end 118a, 119a of four pairs of first through holes and second through holes is exposed on the second surface 113b of the ceramic plate.

[0058] Figure 6This is a cross-sectional view of a ceramic plate according to an embodiment of the present invention after the conductive silicon pad has been formed. Figure 7 This is a bottom view of a ceramic plate according to an embodiment of the present invention after the conductive silicon pad has been formed.

[0059] Reference Figure 6 and Figure 7 In order to electrically connect the first electrode 116 and the second electrode 117, the conductive silicon pad 120 is joined to one end 118a and 119a of the first through hole and the second through hole at the second surface 113b of the ceramic plate.

[0060] The conductive silicone pad 120 is formed by coating liquid conductive silicone, which includes conductive fillers composed of silver (Ag), nickel (Ni), graphite, or mixtures thereof. The conductive silicone, coated to bond the conductive silicone pad 120 to one end 118a, 119a of the first and second through holes, is cured at a temperature of 100°C to 150°C. The conductive silicone pad 120 formed by curing the conductive silicone can, for example, be a rectangular hexahedron with a thickness of 50 μm or more but less than 150 μm. If the thickness of the conductive silicone pad 120 is less than 50 μm, it is difficult to achieve a uniform thickness; if it exceeds 150 μm, the bonding between the ceramic plate 112 and the base 114 may be unstable.

[0061] The conductive silicone is in a liquid state and may contain silver (Ag), silica, ethyl ester, siloxane, silicone, and copper oxide. The conductive filler may be silver (Ag) or a conductive filler composed of silver (Ag), nickel (Ni), graphite, or mixtures thereof. Relative to 100 parts by weight (wt%) of the conductive silicone, it may contain 80-100 parts by weight of silver (Ag), 1-5 parts by weight of silica and / or ethyl ester, 1-5 parts by weight of siloxane and silicone, and 0.1-1 parts by weight of copper oxide. In this case, the siloxane and silicone may be dimethyl or methyl hydrogen.

[0062] The conductive silicon pad 120 has an elastic modulus of less than 100 MPa at room temperature (25°C), preferably about 10 MPa. In contrast, the polyimide used in prior art CCLs has a high elastic modulus of over 10,000 MPa. Therefore, the conductive silicon pad 120 can alleviate the thermal stress applied to the ceramic plate 112 due to temperature differences.

[0063] Figure 8This is a bottom view of a ceramic plate according to an embodiment of the present invention, showing the conductive silicon pad tightly attached to the through hole.

[0064] The conductive silicon pad 120 is formed by coating liquid conductive silicone. The liquid conductive silicone is applied in close contact with and onto one end 118a and 119a of the first and second through holes, thus eliminating or minimizing the contact area between the conductive silicon pad 120 and one end 118a and 119a of the through holes. Figure 3 The gap formed at point B).

[0065] Furthermore, when there is a gap 122 between the through holes 118 and 119 and the ceramic layers 112b and 112c, the applied conductive silicone can fill the gap 122 to eliminate air bubbles. Specific details are as follows.

[0066] As described above, through holes 118 and 119 are formed by filling the holes penetrating the ceramic layers 112b and 112c with a conductive material. At this time, gaps or crevices 122 may be formed between the filled conductive material and the ceramic layers 112b and 112c. In this case, liquid conductive silicone can fill the gap 122 between one end 118a and 119a of the through hole and the surrounding ceramic layer.

[0067] Table 1 compares the resistance of ceramic plates in embodiments of the present invention with those in the prior art. In embodiments of the present invention, a conductive silicon pad 120 is used to electrically connect the first electrode 116 and the second electrode 117, while in the prior art, a CCL 20 is used to electrically connect the first electrode 16 and the second electrode 17.

[0068] [Table 1]

[0069] The resistance between the first and second electrodes was measured using a resistance meter at 25°C and 200°C. At 25°C, resistance values ​​below 10Ω were measured in both the embodiments of the present invention and in the ceramic plates of the prior art.

[0070] At 200°C, the embodiments of the present invention show resistance values ​​below 100Ω, while the resistance of prior art ceramic plates was not measured. That is, in the embodiments of the present invention, because the conductive silicon pad 120 is in close contact with the vias 118 and 119, and the conductive silicon pad 120 is used to relieve thermal stress, the electrical connection between the conductive silicon pad 120 and the vias 118 and 119 is maintained. However, in the case of prior art ceramic plates, it was confirmed that poor contact between CCL 20 and vias 16 and 17 resulted in no resistance being measured.

[0071] Figure 9 This is a cross-sectional view of a ceramic plate according to another embodiment of the present invention before the formation of the conductive silicon pad. Figure 10This is a cross-sectional view of a ceramic plate according to another embodiment of the present invention after the formation of a conductive silicon pad.

[0072] Regarding the content mentioned above, and Figure 9 and Figure 10 Repeated parts will have their related explanations omitted.

[0073] Reference Figure 9 and Figure 10 A cavity 130 is formed by removing a portion of the third ceramic layer 112c from the second surface 113b of the ceramic plate. The cavity 130 is formed in the exposed portions of the first and second through holes. Therefore, the ends 118a and 119a of the first and second through holes are exposed to the outside via the cavity 130. The cavity 130 can, for example, be formed in a rectangular hexahedral shape, and its depth d can be more than 50 μm and less than 150 μm.

[0074] The conductive silicone is applied in a manner that fills the cavity 130. Therefore, the conductive silicone pad 132 is disposed within the cavity 130. Since the conductive silicone pad 132 is disposed within the cavity 130, it can be formed so that it does not protrude from the second surface 113b of the ceramic plate. Thus, when the second surface 113b of the ceramic plate bonded to the base 114 has a flat shape, the base 114 and the ceramic plate 112 can be better bonded.

[0075] As described above, although the present invention has been illustrated with specific constituent elements and defined embodiments and drawings, this is only provided to help to more fully understand the present invention. The present invention is not limited to the above embodiments, and those skilled in the art can make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the concept of the present invention should not be limited to the illustrated embodiments, but should be understood to include not only the appended claims, but also all technical ideas that are equivalent to or have equivalent variations of the appended claims. Furthermore, the above embodiments can be combined and applied to each other as needed.

Claims

1. An electrostatic chuck comprising a ceramic plate having a first side and a second side, wherein, The ceramic plate includes: Multiple ceramic layers; The first electrode and the second electrode are disposed between the plurality of ceramic layers; A first through-hole and a second through-hole penetrate a portion of the ceramic layer. The first through-hole is connected to the first electrode, and the second through-hole is connected to the second electrode. One end of the first through-hole and one end of the second through-hole are exposed on the second surface of the ceramic plate. A conductive silicon pad is disposed on the second side of the ceramic plate and is joined to one end of the first through hole and one end of the second through hole to electrically connect the first through hole and the second through hole.

2. The electrostatic chuck according to claim 1, wherein, The conductive silicon pad is formed by coating liquid conductive silicone.

3. The electrostatic chuck according to claim 2, wherein, A portion of the conductive silicone is disposed between one end of the first through hole and the ceramic layer through which the first through hole penetrates.

4. The electrostatic chuck according to claim 2, wherein, The conductive silicone includes conductive fillers composed of silver, nickel, graphite, or mixtures thereof.

5. The electrostatic chuck according to claim 1, wherein, The thickness of the conductive silicon pad is greater than 50 μm and less than 150 μm.

6. The electrostatic chuck according to claim 1, wherein, The elastic modulus of the conductive silicon pad at 25°C is close to 10 MPa.

7. The electrostatic chuck according to claim 1, wherein, The ceramic plate includes a cavity formed at a predetermined depth on the second surface. One end of the first through hole and one end of the second through hole are exposed in the cavity. The conductive silicon pad is disposed within the cavity.

8. The electrostatic chuck according to claim 7, wherein, The depth of the cavity is greater than 50 μm and less than 150 μm.

Images