Preparation method of multilayer co-fired ceramic plate of electrostatic chuck

Abstract

The invention discloses a preparation method of a multilayer co-fired ceramic disc of an electrostatic chuck, and belongs to the technical field of electrostatic chucks, and the preparation method comprises the following steps: S1, preparing organic suspension ceramic slurry with certain viscosity and uniform dispersion; s2, the ceramic slurry is manufactured into a ceramic green sheet with a certain thickness in a tape casting mode; s3, various holes are formed in the ceramic green sheet; s4, preparing metal electrode slurry; s5, metal conduction slurry is filled in the interconnection conduction holes of the green body sheet in a hole filling mode, and an adsorption electrode layer, a heating electrode layer, a parallel electrode layer and an interconnection conduction Pad are manufactured in a silk-screen printing mode; s6, green body blocks are manufactured; s7, laminating together by using a laminating machine in a positioning and laminating manner; s8, the laminated green ceramic plates are placed in a debinding furnace for glue discharging; and S9, performing high-temperature sintering in a high-temperature sintering furnace to obtain the ceramic.

Description

Technical Field

[0001] The invention relates to the technical field of electrostatic chucks, and in particular to a method for preparing a multi-layer co-fired ceramic disc of an electrostatic chuck. Background Art

[0002] Generally speaking, an electrostatic chuck is made of a ceramic disk and a metal base. The ceramic disk is mostly made of a simple structure of a dielectric layer and an adsorption electrode. The built-in adsorption electrode in the ceramic disk is used to adsorb and clamp the wafer after power is turned on. The heating electrode is placed outside the ceramic disk and attached between the ceramic disk and the metal base. The cooling air path is built into the metal base. Therefore, this type of commonly constructed electrostatic chuck places the adsorption electrode, heating electrode and cooling air path in three areas (inside the ceramic disk, between the ceramic disk and the metal base, and inside the metal base).

[0003] The main defects of the prior art are: this type of commonly constructed electrostatic chuck places the adsorption electrode, heating electrode and cooling gas path in three areas respectively, and the ceramic disk, heating electrode and metal base are assembled by bonding; during the operation of this type of electrostatic chuck, since the heating electrode is attached to the outside of the ceramic disk, the heating efficiency, heat conduction rate and temperature uniformity control will be affected by the thermal conductivity of the bonding material and the consistency of the thickness of the bonding layer, and the advantages of the excellent and uniform thermal conductivity of the ceramic disk are not fully utilized. At the same time, the cooling gas path is built into the metal base, which is far away from the working surface of the classic chuck, which will also cause a series of adverse effects such as poor temperature uniformity control during the operation of the electrostatic chuck and cooling gas leakage caused by insufficient sealing during the bonding process. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a multi-layer co-fired ceramic disc of an electrostatic chuck, so as to solve the problem raised in the background technology.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] A method for preparing a multi-layer co-fired ceramic disc of an electrostatic chuck, the preparation method comprising:

[0007] S1: adding a certain amount of ceramic powder, 5% to 15% of resin powder, 2% to 7% of plasticizer, 0.1% to 2% of dispersant, 1% to 6% of inorganic additive, and 50% to 100% of organic solvent into a ball mill in proportion, and ball milling is performed at a speed of 20 to 50 rpm / min for 24 to 96 hours. After ball milling, an organic suspended ceramic slurry with a certain viscosity and uniform dispersion is obtained;

[0008] S2: The ceramic slurry is tape-casted to produce a ceramic green sheet with a certain thickness, wherein the thickness of the green sheet is 200 to 800 um, and the thickness difference of a single sheet is within ±20 um. The tape-casted ceramic green sheet is cut into square ceramic green sheets of a size that meets the use requirements;

[0009] S3: machining positioning holes, interconnection holes, adsorption electrode holes and heating electrode holes on the ceramic green sheet by mechanical processing;

[0010] S4: adding a certain amount of metal powder, 5% to 20% of a binder, 1% to 30% of an inorganic additive powder, 0.1% to 1% of a dispersant, and 30% to 60% of an organic solvent into a mixer according to a certain proportion and mixing them evenly; after mixing evenly, a three-roll mill is used for rolling and dispersing to produce a metal electrode slurry with a fineness of less than 10 um and a viscosity of 50,000 to 300,000 cps;

[0011] S5: Filling the interconnection holes of the green sheet with metal conductive paste by hole filling, and respectively manufacturing the adsorption electrode layer, the heating electrode layer, the parallel electrode layer, and the interconnection conductive pad by screen printing, with the printed electrode thickness of 5 to 20 um, and the printing thickness range of within ±0.5 um;

[0012] S6: The green sheets filled with metal conductive paste and printed with interconnect conductive pads are laminated together by a laminating machine to produce green blocks, and ceramic built-in gas paths are produced on the surface of the green blocks by mechanical processing;

[0013] S7: The dielectric layer, the adsorption electrode layer, the heating electrode layer, the parallel electrode layer, the green body after the built-in gas path is processed, the green body after the adsorption electrode hole and the heating electrode hole are processed, and the positioning holes are used to position the green body according to the product construction sequence, and the positioning and laminating methods are used by a laminating machine. During the lamination, the pressure is 20T to 500T, the temperature is 30℃ to 90℃, and the time is 1min to 10min, so as to produce a green body ceramic disc with a multi-layer internal structure;

[0014] S8: placing the laminated green ceramic disc in a degreasing furnace, degreasing and debinding at 300-550° C. in an air or nitrogen atmosphere, and maintaining the highest temperature for 20 h to 96 h to completely remove the organic matter in the ceramic green disc;

[0015] S9: placing the degreased and debinded ceramic disc in a high-temperature sintering furnace, and sintering it at 1300-1800°C in any one or more protective atmospheres such as N2, H2, Ar, etc. to form porcelain.

[0016] Preferably, the ceramic powder is any one of Al2O3, AlN, SiC, and Si3N4.

[0017] Preferably, the metal powder is any one of W, Mo, Mn, Ag, Pd, and Pt.

[0018] The above technical solution has the following beneficial effects:

[0019] The present application provides a preparation method for preventing delamination and cracking of the internal electrodes and ceramics of the ceramic disk and bulging and cracking of the surface of the ceramic disk during the co-firing process by using a ceramic disk with a multi-layer structure;

[0020] The present application places the heating electrode and the gas path inside the ceramic disk, making full use of the advantages of ceramics having excellent and uniform thermal conductivity, and can provide a ceramic disk required for an electrostatic chuck with better temperature uniformity control;

[0021] The present application changes the gas path in the electrostatic chuck from the metal base to the ceramic disk. After the gas path is built into the ceramic disk, the leakage of cooling gas in the process of leading the cooling gas from the metal base to the surface of the ceramic disk can be effectively avoided. At the same time, the heating electrode is built into the ceramic disk, which further simplifies the subsequent mounting and assembly process of the electrostatic chuck. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a schematic structural diagram of a multi-layer co-fired ceramic disc of an electrostatic chuck. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] The manufacturing processes involved in this application mainly include: ceramic slurry production (ball milling), tape casting (green sheet forming), metal conductive slurry production, electrode screen printing, mechanical processing (such as positioning hole processing, conductive hole processing, electrode hole processing, gas path processing), lamination (multi-layer stacking), debinding and degreasing, high-temperature sintering, the ceramic slurry produced by ball milling is tape-casted to form a ceramic green sheet of a certain thickness, and metal electrode layers such as adsorption electrodes, heating electrodes, and parallel electrodes built into the ceramic disk are produced on the ceramic green sheet by screen printing; positioning holes for lamination, multi-layer interconnected conductive holes, electrode holes, built-in gas paths, etc. are processed on the ceramic green sheet by mechanical processing. ; Fill the multi-layer interconnected conductive holes with metal conductive slurry; after the metal electrodes, conductive layers, gas paths, etc. inside the ceramic disk are processed and manufactured, they are positioned using positioning holes, and a laminating machine is used to perform multi-layer alignment and stacking under certain temperature, pressure, and time conditions, so that the green layers of the ceramic disk are tightly fitted together, and the green ceramic disk is completed; the green ceramic disk is placed in a degreasing furnace, and the organic binder in the ceramic disk is discharged under certain temperature and atmosphere conditions; the degreased ceramic disk is placed in a high-temperature sintering furnace, and the metal electrodes and the ceramic layers are multi-layered co-fired under certain temperature and atmosphere conditions, so that the ceramic disk is sintered into porcelain, thereby producing a ceramic disk with a multi-layer structure that meets the requirements of mechanical and electrical properties;

[0025] refer to Figure 1 , a method for preparing a multilayer co-fired ceramic disc of an electrostatic chuck, the preparation method comprising:

[0026] S1: adding a certain amount of ceramic powder, 5% to 15% of resin powder, 2% to 7% of plasticizer, 0.1% to 2% of dispersant, 1% to 6% of inorganic additive, and 50% to 100% of organic solvent into a ball mill in proportion, and ball milling is performed at a speed of 20 to 50 rpm / min for 24 to 96 hours. After the ball milling is completed, an organic suspended ceramic slurry with a certain viscosity and uniform dispersion is obtained, and the ceramic powder is any one of Al2O3, AlN, SiC, and Si3N4;

[0027] In some embodiments, ceramic powder, 5% resin powder, 2% plasticizer, 0.1% dispersant, 1% inorganic additive, and 50% organic solvent are added to a ball mill in proportion, and ball milled for 24 hours at a rotation speed of 20 rpm / min. After the ball milling is completed, an organic suspended ceramic slurry with a certain viscosity and uniform dispersion is obtained, wherein the ceramic powder is any one of Al2O3, AlN, SiC, and Si3N4;

[0028] In some embodiments, ceramic powder, 15% of resin powder, 7% of plasticizer, 2% of dispersant, 6% of inorganic additive, and 100% of organic solvent are added to a ball mill in proportion, and ball milling is performed at a speed of 50 rpm / min for 96 hours. After the ball milling is completed, an organic suspended ceramic slurry with a certain viscosity and uniform dispersion is obtained, and the ceramic powder is any one of Al2O3, AlN, SiC, and Si3N4;

[0029] S2: The ceramic slurry is tape-casted to produce a ceramic green sheet with a certain thickness, wherein the thickness of the green sheet is 200 to 800 um, and the thickness difference of a single sheet is within ±20 um. The tape-casted ceramic green sheet is cut into square ceramic green sheets of a size that meets the use requirements;

[0030] In some embodiments, the ceramic slurry is tape-cast to produce a ceramic green sheet with a certain thickness, wherein the thickness of the green sheet is 200um or 800um, and the thickness difference of a single sheet is within -20um to +2;

[0031] S3: machining positioning holes, interconnection holes, adsorption electrode holes and heating electrode holes on the ceramic green sheet by mechanical processing;

[0032] S4: adding a certain amount of metal powder, 5% to 20% of a binder, 1% to 30% of an inorganic additive powder, 0.1% to 1% of a dispersant, and 30% to 60% of an organic solvent into a mixer according to a certain proportion and mixing them evenly; after mixing evenly, using a three-roll mill to roll and disperse them to produce a metal electrode slurry with a fineness of less than 10um and a viscosity of 50,000 to 300,000 cps; the metal powder is any one of W, Mo, Mn, Ag, Pd, and Pt;

[0033] In some embodiments, the metal conductive paste is prepared by the following method: metal powder, 5% binder, 1% inorganic additive powder, 0.1% dispersant, and 30% organic solvent are added to a blender in proportion and mixed evenly, and then a three-roll mill is used for rolling and dispersion to produce a metal electrode paste with a fineness of less than 10um and a viscosity of 50000cps, wherein the metal powder is any one of W, Mo, Mn, Ag, Pd, and Pt;

[0034] In some embodiments, the metal conductive paste is prepared by the following method: metal powder, 20% binder, 30% inorganic additive powder, 1% dispersant, and 60% organic solvent are added to a mixer in proportion and mixed evenly, and then a three-roll mill is used for rolling and dispersion to produce a metal electrode paste with a fineness of less than 10um and a viscosity of 300000cps, wherein the metal powder is any one of W, Mo, Mn, Ag, Pd, and Pt;

[0035] S5: Filling the interconnection conductive holes of the green sheet with metal conductive paste by hole filling, and respectively manufacturing the adsorption electrode layer 2, the heating electrode layer 3, the parallel electrode layer 5, and the interconnection conductive Pad 6 by screen printing, the printed electrode thickness is 5 to 20 um, and the printing thickness range is within ±0.5 um. In some embodiments, the thickness of the printed electrode is 5 um or 20 um, or 15 um;

[0036] S6: The green sheets filled with metal conductive paste 4 and printed with interconnect conductive Pad 6 are laminated together by a laminating machine to produce green blocks, and ceramic built-in gas paths 7 are produced on the surface of the green blocks by mechanical processing;

[0037] S7: The dielectric layer 1, the adsorption electrode layer 2, the heating electrode layer 3, the parallel electrode layer 5, the green body after the built-in gas path 7 is processed, and the green body after the adsorption electrode hole 8 and the heating electrode hole 9 are processed, according to the product construction sequence, positioned by positioning holes, and stacked together by positioning and stacking using a laminating machine. During the stacking, the pressure is 20T to 500T, the temperature is 30℃ to 90℃, and the time is 1min to 10min, so as to produce a green body ceramic disc with a multi-layer internal structure. In some embodiments, during the stacking, the pressure is 20T or 500T, the temperature is 30℃ or 90℃, and the time is 1min or 10min;

[0038] S8: placing the laminated green ceramic disc in a degreasing furnace, degreasing and debinding at 300-550° C. in an air or nitrogen atmosphere, and keeping the highest temperature for 20 h to 96 h, so as to remove organic matter from the ceramic green body. In some embodiments, the degreasing and debinding temperature is 300° C. or 550° C., and the keeping time at the highest temperature is 20 h or 96 h;

[0039] S9: placing the degreased and debinded ceramic disc in a high-temperature sintering furnace, and sintering the disc at 1300-1800° C. into ceramic in any one or more protective atmospheres such as N2, H2, Ar, etc. In some embodiments, the high-temperature sintering temperature is 1300° C. or 1800° C.;

[0040] During the preparation of the multi-layer co-fired ceramic disc, the surface and internal conditions of the ceramics fired under different parameters are shown in Table 1 below:

[0041] Table 1:

[0042]

[0043]

[0044] According to Table 1, the multilayer ceramics prepared by the method of the present application can have no delamination, no bulging and no cracking after sintering, and meet the requirements of electrostatic chuck ceramics;

[0045] The present application provides a preparation method for preventing delamination and cracking of the internal electrodes and ceramics of the ceramic disk and bulging and cracking of the surface of the ceramic disk during the co-firing process by using a ceramic disk with a multi-layer structure;

[0046] The present application places the heating electrode and the gas path inside the ceramic disk, making full use of the advantages of ceramics having excellent and uniform thermal conductivity, and can provide a ceramic disk required for an electrostatic chuck with better temperature uniformity control;

[0047] The present application changes the gas path in the electrostatic chuck from the metal base to the ceramic disk. After the gas path is built into the ceramic disk, the leakage of cooling gas in the process of leading the cooling gas from the metal base to the surface of the ceramic disk can be effectively avoided. At the same time, the heating electrode is built into the ceramic disk, which further simplifies the subsequent mounting and assembly process of the electrostatic chuck.

[0048] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. A method for preparing a multi-layer co-fired ceramic disc for an electrostatic chuck, characterized in that: The preparation method comprises: S1: adding a certain amount of ceramic powder, 5% to 15% of resin powder, 2% to 7% of plasticizer, 0.1% to 2% of dispersant, 1% to 6% of inorganic additive, and 50% to 100% of organic solvent into a ball mill in proportion, and ball milling is performed at a speed of 20 to 50 rpm / min for 24 to 96 hours. After ball milling, an organic suspended ceramic slurry with a certain viscosity and uniform dispersion is obtained; S2: The ceramic slurry is tape-casted to produce a ceramic green sheet with a certain thickness, wherein the thickness of the green sheet is 200 to 800 um, and the thickness difference of a single sheet is within ±20 um. The tape-casted ceramic green sheet is cut into square ceramic green sheets of a size that meets the use requirements; S3: machining positioning holes, interconnection holes, adsorption electrode holes and heating electrode holes on the ceramic green sheet by mechanical processing; S4: adding a certain amount of metal powder, 5% to 20% of a binder, 1% to 30% of an inorganic additive powder, 0.1% to 1% of a dispersant, and 30% to 60% of an organic solvent into a mixer according to a certain proportion and mixing them evenly; after mixing evenly, a three-roll mill is used for rolling and dispersing to produce a metal electrode slurry with a fineness of less than 10 um and a viscosity of 50,000 to 300,000 cps; S5: Filling the interconnection holes of the green sheet with metal conductive paste by hole filling, and respectively manufacturing the adsorption electrode layer, the heating electrode layer, the parallel electrode layer, and the interconnection conductive pad by screen printing, with the printed electrode thickness of 5 to 20 um, and the printing thickness range of within ±0.5 um; S6: The green sheets filled with metal conductive paste and printed with interconnect conductive pads are laminated together by a laminating machine to produce green blocks, and ceramic built-in gas paths are produced on the surface of the green blocks by mechanical processing; S7: The dielectric layer, the adsorption electrode layer, the heating electrode layer, the parallel electrode layer, the green body after the built-in gas path is processed, the green body after the adsorption electrode hole and the heating electrode hole are processed, and the positioning holes are used to position the green body according to the product construction sequence, and the positioning and laminating methods are used by a laminating machine. During the lamination, the pressure is 20T to 500T, the temperature is 30℃ to 90℃, and the time is 1min to 10min, so as to produce a green body ceramic disc with a multi-layer internal structure; S8: placing the laminated green ceramic disc in a degreasing furnace, degreasing and debinding at 300-550° C. in an air or nitrogen atmosphere, and maintaining the highest temperature for 20 h to 96 h to completely remove the organic matter in the ceramic green disc; S9: placing the degreased and debinded ceramic disc in a high-temperature sintering furnace, and sintering it at 1300-1800°C in any one or more protective atmospheres such as N2, H2, Ar, etc. to form porcelain.

2. The method for preparing a multi-layer co-fired ceramic disc for an electrostatic chuck according to claim 1, characterized in that: The ceramic powder is any one of Al2O3, AlN, SiC, and Si3N4.

3. The method for preparing a multi-layer co-fired ceramic disc for an electrostatic chuck according to claim 1, characterized in that: The metal powder is any one of W, Mo, Mn, Ag, Pd and Pt.

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