Electrostatic chuck

Abstract

This invention provides an electrostatic chuck. According to an embodiment of the invention, the electrostatic chuck includes a ceramic plate having a first side and a second side. The ceramic plate includes: 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 and 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 on the second side of the ceramic plate; and a conductive silicon pad disposed on the second side 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] This invention relates to an electrostatic chuck, which uses conductive silicone to electrically connect electrodes embedded in a ceramic plate. Background Technology

[0002] Typically, semiconductor devices or LCD display devices are manufactured by sequentially stacking multiple thin film layers, including dielectric and electrode layers, on a glass substrate, flexible substrate, or semiconductor wafer substrate, and then patterning them. To support the glass substrate, flexible substrate, semiconductor wafer substrate, etc., and to perform semiconductor processing, ceramic holders (also known as ceramic substrates) such as electrostatic chucks (ESCs) or ceramic heaters are used. Electrostatic chucks are primarily used in dry etching processes for the thin film layers formed on the substrate.

[0003] Electrostatic chucks are structural components used inside the vacuum chambers of semiconductor and LCD manufacturing equipment to place substrates such as semiconductor wafers. They are components that use electrostatic force to hold the substrate in place and to heat or cool it. A representative example of an electrostatic chuck is the ceramic electrostatic chuck.

[0004] Figure 1 This is a cross-sectional view showing a prior art ceramic electrostatic chuck. Figure 2 This is a bottom view showing the bottom surface of a ceramic plate from the prior art.

[0005] Reference Figure 1 and Figure 2 The electrostatic chuck 10 consists of a ceramic plate 12 and a base 14. The base 14 can be formed of materials such as metal or metal-ceramic composites (Al-SiC, Al-TiC, etc.). The ceramic plate 12 and the base 14 are bonded together with an adhesive such as silicone resin.

[0006] The ceramic plate 12 is used to adsorb semiconductor wafers and the like, and is composed of multiple ceramic layers stacked together. Inside the ceramic plate 12, electrodes 16, such as chucking electrodes, RF electrodes, and heating element layers, are disposed between the ceramic layers. Figure 1 An example is shown of an electrostatic chuck with two layers of attracting electrodes (electrode 16).

[0007] The two attracting electrodes (electrode 16) are electrically connected through conductive vias 18 and copper clad laminate (CCL) 20 for bridging these conductive vias 18. The film-shaped CCL 20 serves as the electrical connection component and consists of a metal layer (e.g., copper) 22 and a polyimide layer 24 for electrically insulating the metal layer 22.

[0008] However, since both CCL 20 and through-hole 18 are solids with a certain degree of hardness, they may not adhere tightly together, resulting in a small gap at contact A. In this case, during the process of using the electrostatic chuck 10, when the temperature of the ceramic plate 12 rises, air bubbles present in the gap at contact A will expand, causing poor contact between CCL 20 and through-hole 18. Furthermore, since the ceramic plate 12 is used in environments with large temperature differences, such as -100℃ to 200℃, poor contact may also occur at contact A due to the expansion and contraction of the polyimide in CCL 20.

[0009] Furthermore, due to this temperature difference, the ceramic plate 12 and the base 14 will expand and contract. At this time, the ceramic plate 12 and the base 14, formed of different materials, have different coefficients of thermal expansion, thus generating stress due to expansion and contraction. The silicone resin adhesive between the ceramic plate 12 and the base 14 serves to disperse and alleviate this stress. However, when CCL 20, including the metal layer 22 and the polyimide layer 24, is present in the bonding layer between the ceramic plate 12 and the base 14, it hinders the dispersion of this stress, leading to the ceramic plate 12 peeling or cracking. Summary of the Invention

[0010] The problem the invention aims to solve

[0011] The purpose of this invention is to provide an electrical connection component that can be tightly joined with a through hole.

[0012] Furthermore, the present invention aims to provide an electrical connection component that can alleviate thermal stress between the ceramic plate and the base.

[0013] means for solving problems

[0014] An embodiment of the present invention provides an electrostatic chuck, comprising a ceramic plate having a first side and a second side, the ceramic plate comprising: 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 and 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 on the second side of the ceramic plate; and a conductive silicon pad disposed on the second side of the ceramic plate and coupled 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.

[0015] An embodiment of the present invention provides an electrostatic chuck, wherein the conductive silicon pad is formed by coating liquid conductive silicone.

[0016] 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 through which the first through hole penetrates.

[0017] An embodiment of the present invention provides an electrostatic chuck, wherein the conductive silicone comprises a conductive filler composed of silver (Ag), nickel (Ni), graphite, or a mixture thereof.

[0018] An embodiment of the present invention provides an electrostatic chuck, wherein the thickness of the conductive silicon pad is more than 50 μm and less than 150 μm.

[0019] An embodiment of the present invention provides an electrostatic chuck, wherein the conductive silicon pad has an elastic modulus of approximately 10 MPa at 25°C.

[0020] An embodiment of the present invention provides an electrostatic chuck, 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, and the conductive silicon pad is disposed in the cavity.

[0021] An embodiment of the present invention provides an electrostatic chuck, wherein the depth of the cavity is more than 50 μm and less than 150 μm.

[0022] An embodiment of the present invention provides an electrostatic chuck, comprising a ceramic plate having a first side and a second side, the ceramic plate comprising: 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 on the second side of the ceramic plate; and a conductive silicon pad disposed on the second side of the ceramic plate and engaged with one end of the through hole, a portion of the conductive silicon pad being disposed between one end of the through hole and the ceramic plate through which the through hole penetrates.

[0023] Invention Effects

[0024] According to embodiments of the present invention, short circuits can be prevented in the electrical connections between electrodes embedded in the ceramic plate.

[0025] Furthermore, according to embodiments of the present invention, thermal stress between the ceramic plate and the base can be alleviated. Attached Figure Description

[0026] Figure 1 This is a cross-sectional view showing a prior art ceramic electrostatic chuck.

[0027] Figure 2 This is a bottom view showing the bottom surface of a ceramic plate from the prior art.

[0028] Figure 3 This is a schematic cross-sectional view of an electrostatic chuck according to an embodiment of the present invention.

[0029] 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.

[0030] 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.

[0031] Figure 6 This is a cross-sectional view of a ceramic plate according to an embodiment of the present invention after the formation of a conductive silicon pad.

[0032] 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.

[0033] Figure 8 This 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.

[0034] 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.

[0035] Figure 10 This 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.

[0036] Explanation of reference numerals in the attached figures

[0037] 100: Electrostatic chuck

[0038] 112: Ceramic slab

[0039] 114: Base

[0040] 116: First electrode

[0041] 117: Second electrode

[0042] 118: First through hole

[0043] 119: Second through hole

[0044] 120: Conductive Silicon Pad Detailed Implementation

[0045] In the following description, embodiments disclosed in this specification will be described in detail with reference to the accompanying drawings. However, regardless of the reference numerals, the same or similar constituent elements will be given the same reference numerals, and repeated descriptions thereof will be omitted. In the following description of embodiments of the invention, when referring to layers (films), regions, patterns, or structures formed on a substrate, layers (films), regions, pads, or patterns as "on" or "under", both "on" and "under" include cases where they are formed "directly" or "indirectly through other layers".

[0046] Furthermore, the reference datums for the top / above, bottom / below, left / left side, right / right side, vertical (vertical), and horizontal (horizontal) of each layer are explained with reference to the accompanying drawings. The thickness or size of each layer in the accompanying drawings has been exaggerated, omitted, or shown schematically for ease of explanation and clarity. Also, the sizes of the constituent elements do not fully reflect their actual sizes.

[0047] In this description, expressions such as “include,” “possess,” or “comprise” are intended to indicate certain features, figures, steps, operations, elements, or combinations thereof, and should not be construed as the presence or possibility of one or more other features, figures, steps, operations, elements, or combinations thereof other than those described.

[0048] Furthermore, terms such as "first," "second," etc., can be used to describe a variety of constituent elements, but the constituent elements are not limited by the terms; the terms are only used for the purpose of distinguishing one constituent element from another.

[0049] Furthermore, the term "about" refers to the general error range of various values ​​that is readily known to those skilled in the art, and the term "about" may mean within ±0.5% or at most 1% of the indicated value. Additionally, the term "about" may indicate measurement error due to limitations of the measurement method.

[0050] Furthermore, when describing the embodiments disclosed in this specification, if it is determined that the detailed description of relevant known technologies may obscure the main idea of ​​the embodiments disclosed in this specification, its detailed description will be omitted.

[0051] The accompanying drawings are provided only to facilitate understanding of the embodiments disclosed in this specification. They should not be construed as limiting the technical ideas disclosed in this specification, but should be understood to include all modifications, equivalents, and even substitutions within the scope of the inventive concept and technology.

[0052] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0053] Figure 3 This is a schematic cross-sectional view of an electrostatic chuck according to an embodiment of the present invention.

[0054] According to an embodiment of the present invention, an electrostatic chuck 100 is provided in an apparatus for performing semiconductor processes. It is used to support various substrates for processing, such as glass substrates, flexible substrates, and semiconductor wafer substrates, in processes such as plasma-enhanced chemical vapor deposition. It can also be used as a heater to achieve accurate temperature control and heat treatment requirements in processes such as plasma deposition in order to realize precision processes such as miniaturization of wiring in semiconductor devices.

[0055] Reference Figure 3 According to an embodiment of the present invention, the electrostatic chuck 100 has a ceramic plate 112 and a base 114. The ceramic plate 112 has a stacked structure of multiple ceramic layers (first ceramic layer 112a, second ceramic layer 112b, third ceramic layer 112c), multiple electrodes (first electrode 116, second electrode 117), multiple through holes (first through hole 118, second through hole 119) and a conductive silicon pad 120.

[0056] The ceramic plate 112 is a component for adsorbing and holding substrates such as semiconductor wafers. The ceramic plate 112 has a plate surface (first surface) 113a and a plate back surface (second surface) 113b. The first surface 113a of the ceramic plate 112 is the adsorption surface for adsorbing substrates such as semiconductor wafers. The ceramic plate 112 can be formed into a disk shape with a diameter of about 300 mm and a thickness of about 3 mm by stacking multiple ceramic layers (first ceramic layer 112a, second ceramic layer 112b, and third ceramic layer 112c).

[0057] The ceramic plate 112 is formed of an insulating or dielectric ceramic material, such as Al2O3, Y2O3, ZrO2, AlC, TiN, AlN, TiC, MgO, CaO, CeO2, TiO2, or B. x C y It is formed from materials such as BN, SiO2, SiC, YAG, Mullite, AlF3, or a combination of two or more of them.

[0058] Electrodes (first electrode 116, second electrode 117) are disposed inside the ceramic plate 112. The electrodes (first electrode 116, second electrode 117) of the ceramic plate 112 can be chucking electrodes, radio frequency (RF) electrodes, and / or heating element layers. The electrodes (first electrode 116, second electrode 117) can be formed using processes such as CVD, PVC, thermal spraying, or screen printing.

[0059] The chucking electrodes (first electrode 116, second electrode 117) generate an electric field between the electrode and the substrate, such as a semiconductor wafer, using a direct current (DC) voltage, thereby creating an electrostatic force for attracting and fixing the substrate. During the wafer deposition process, the RF electrode performs an RF grounding function, discharging the current charged by the plasma inside the cavity through an external ground terminal. The heating element layer performs the function of heating the substrate in processes such as etching of the thin film layer formed on the substrate or firing of the photoresist. In embodiments of the present invention, the electrodes (first electrode 116, second electrode 117) may be chucking electrodes, but the present invention is not limited thereto.

[0060] The attracting electrodes (first electrode 116, second electrode 117) can be formed into a structure of two or more layers to distribute the electric field more uniformly and to precisely control the fixing force of the semiconductor wafer by adjusting the voltage between the electrodes. The electrodes (first electrode 116, second electrode 117) are disposed between multiple ceramic layers (first ceramic layer 112a, second ceramic layer 112b, third ceramic layer 112c). Each electrode (first electrode 116, second electrode 117) and the ceramic layers (first ceramic layer 112a, second ceramic layer 112b, third ceramic layer 112c) can be stacked alternately layer by layer. In other words, they can be stacked in the order of first ceramic layer 112a, first electrode 116, second ceramic layer 112b, second electrode 117, and third ceramic layer 112c.

[0061] 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. The electrodes (first electrode 116, second electrode 117) may be formed of tungsten (W), molybdenum (Mo), silver (Ag), gold (Au), niobium (Nb), titanium (Ti), or alloys thereof. The electrodes (first electrode 116, second electrode 117) embedded in the ceramic plate 112 receive current supply through electrode rods 128 disposed within the base 114.

[0062] The first electrode 116 and the second electrode 117 are electrically connected through conductive vias (first via 118 and second via 119). The conductive vias (first via 118 and second via 119) may be cylindrical with one end and the other end. The first via 118 and the second via 119 penetrate a portion of the ceramic layers (first ceramic layer 112a, second ceramic layer 112b, and third ceramic layer 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, and one end of the first via 118 is connected to the lower surface of the first electrode 116. The second via 119 vertically penetrates the third ceramic layer 112c at a different position than the first via 118, and one end of the second via 119 is 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 the conductive silicon pad 120 on the second surface 113b of the ceramic plate. The vias (first via 118, second via 119) and the conductive silicon pad 120 will be described in detail below.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] Reference Figure 4 and Figure 5One 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.

[0067] The ceramic plate 112 is manufactured by sintering multiple ceramic layers (first ceramic layer 112a, second ceramic layer 112b, and third ceramic layer 112c). At this time, electrodes (first electrode 116 and second electrode 117) are formed on the surface of a portion of the ceramic layers (first ceramic layer 112a, second ceramic layer 112b, and third ceramic layer 112c), thereby forming a stacked structure.

[0068] To form conductive vias (first via 118, second via 119) for electrical connection between the stacked electrodes (first electrode 116, second electrode 117), holes are formed along a direction vertically intersecting the electrodes (first electrode 116, second electrode 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.

[0069] To form conductive vias (first via 118, second via 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, 119a of the first and second vias is 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, 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.

[0070] Figure 6 This 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] Figure 8 This 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.

[0076] 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).

[0077] Furthermore, when there is a gap 122 between the through holes (first through hole 118, second through hole 119) and the ceramic layers (second ceramic layer 112b, third ceramic layer 112c), the applied conductive silicone can fill the gap 122 to eliminate air bubbles. Specific details are as follows.

[0078] As described above, the through holes (first through hole 118, second through hole 119) are formed by filling the holes penetrating the ceramic layers (second ceramic layer 112b, third ceramic layer 112c) with a conductive material. At this time, a gap 122 (or slit) may be formed between the filled conductive material and the ceramic layers (second ceramic layer 112b, third ceramic layer 112c). In this case, liquid conductive silicone can fill the gap 122 between one end 118a, 119a of the through hole and the surrounding ceramic layer.

[0079] 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 two layers of attracting electrodes (electrode 16) serving as the first and second electrodes.

[0080] [Table 1]

[0081]

[0082] 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.

[0083] 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 through holes (first through hole 118, second through hole 119), and the conductive silicon pad 120 is used to relieve thermal stress, the electrical connection between the conductive silicon pad 120 and the through holes (first through hole 118, second through hole 119) is maintained. However, in the case of prior art ceramic plates, it was confirmed that poor contact between CCL 20 and through hole 18 resulted in no resistance being measured.

[0084] Figure 9This 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 10 This 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.

[0085] Regarding the content mentioned above, and Figure 9 and Figure 10 Repeated parts will have their related explanations omitted.

[0086] 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.

[0087] 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.

[0088] 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 conductive silicon pad has an elastic modulus of 10 MPa to 100 MPa at 25°C.

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.

9. The electrostatic chuck according to claim 1, wherein, The first electrode and the second electrode are disposed on different planes between the plurality of ceramic layers.

Images