Preparation method of multilayer interconnected ceramic disc of electrostatic chuck

Abstract

The invention discloses a preparation method of a multilayer interconnected ceramic disc of an electrostatic chuck, and belongs to the technical field of electrostatic chucks, and the preparation method comprises the following steps: carrying out ball milling on ceramic powder, resin powder, a plasticizer, a dispersant, an inorganic additive and an organic solvent to obtain ceramic slurry, and preparing a ceramic green sheet; positioning holes, interconnection conducting holes and electrode holes are machined in the cut ceramic green body pieces in a machining mode, and when the interconnection conducting holes in each layer are machined, machining needs to be conducted according to hole machining position coordinates designed in a drawing; metal conduction slurry is filled into interconnection conduction holes of a machined ceramic green body sheet in a hole filling mode, adsorption electrodes and interconnection conduction electrodes are manufactured in a silk-screen printing mode, and when the interconnection conduction electrodes are printed, due to the fact that the positions of all layers of interconnection conduction electrodes are different, according to the requirements of design drawings, the adsorption electrodes and the interconnection conduction electrodes need to be separated from each other. A silk-screen printing plate meeting different position requirements is manufactured; and laminating after filling holes, degreasing after laminating, and sintering at high temperature to obtain the ceramic after degreasing.

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 interconnected ceramic disc of an electrostatic chuck. Background Art

[0002] The electrostatic chuck of the multi-layer interconnected ceramic disk in the prior art mainly includes a dielectric layer, an adsorption electrode, and a multi-layer interconnected conductive layer. Generally speaking, the electrostatic chuck electrostatic ceramic disk is mostly simply constructed of a dielectric layer and an adsorption electrode. The thickness of the ceramic disk is 1 to 2 mm. For ceramic disks with a thickness of more than 2 mm, usually only an interconnected conductive layer is simply added and the position of each layer of the multi-layer interconnected electrodes is fixed.

[0003] The main drawback is that the thickness of the ceramic disc of the common electrostatic chuck of this type is mostly 1 to 2 mm. For thicker ceramic discs above 2 mm, usually Figure 1 As shown, the interconnection conductive layer is simply increased to make the thickness of the ceramic disk meet the requirements; when this method is used to make ceramic disks larger than 2 mm, as the thickness of the ceramic disk continues to increase, the number of multi-layer interconnection layers increases accordingly, and the number of conductive electrodes in the multi-layer interconnection layers continues to increase, so that the thickness of this area continues to stack, resulting in the thickness of this area being significantly higher than other areas without conductive interconnection electrodes after the ceramic disk is sintered, resulting in poor uniformity of the ceramic thickness after sintering. At the same time, when the electrostatic chuck is working, due to continuous power supply, the conductive interconnection electrodes will also generate heat. Due to the heat superposition of the conductive interconnection electrodes in the same position, it is easy to cause the temperature of this area to be higher than other areas, which has an adverse effect on the processing and manufacturing of the wafer. 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 interconnected ceramic disc of an electrostatic chuck 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 interconnected ceramic disc of an electrostatic chuck, wherein the multi-layer interconnected ceramic disc comprises a dielectric layer, an adsorption electrode layer, a plurality of multi-layer interconnected conductive layers, a metal conductive slurry, and an electrode hole, wherein the plurality of multi-layer interconnected conductive layers are staggered with each other, and the method for preparing the multi-layer interconnected ceramic disc comprises the following steps:

[0007] S1: Add a certain amount of ceramic powder, which is any one of Al2O3, AlN, SiC, and Si3N4 materials, 6% to 15% of resin powder, 1% to 6% of plasticizer, 0.1% to 2% of dispersant, 1% to 6% of inorganic additives, and 50% to 120% of organic solvent into a ball mill in proportion, and mill the ball mill 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;

[0008] S2: The organic suspended ceramic slurry is tape-casted to produce a ceramic green sheet of a certain thickness, wherein the thickness of the ceramic green sheet is 200 to 700 μm, and the thickness range of a single ceramic green sheet is within ±20 μm. 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 via holes, and electrode holes from the cut ceramic green sheets by mechanical processing. When machining each layer of interconnection via holes, it is necessary to design the hole machining position coordinates according to the drawings, and machine the interconnection via holes at the corresponding positions of each interconnection layer;

[0010] S4: metal conductive slurry is filled into the interconnection conductive holes of the machined ceramic green sheet by a hole filling method, and adsorption electrodes and interconnection conductive electrodes are respectively produced by a screen printing method. The thickness of the adsorption electrodes and the interconnection conductive electrodes is 5 to 20 um, and the thickness range of the adsorption electrodes and the interconnection conductive electrodes is within ±0.5 um. When the interconnection conductive electrodes are printed, since the positions of each layer of interconnection conductive electrodes are different, it is necessary to produce a screen printing screen that meets the requirements of different positions according to the requirements of the design drawings to ensure that each layer of interconnection conductive electrodes corresponds to the interconnection conductive holes one by one;

[0011] S5: The ceramic green sheets after the holes are filled are positioned by positioning holes according to the product construction sequence, and are stacked together by positioning and stacking using a stacking machine. During the stacking, the pressure is 50T to 500T, the temperature is 30℃ to 80℃, and the time is 1min to 20min, so as to produce a green ceramic disc with a multi-layer interconnection structure, and the multi-layer interconnection conductive layer is evenly distributed inside the ceramic disc;

[0012] S6: placing the laminated green ceramic disc in a degreasing furnace, degreasing and debinding at 350° C. to 550° C. in an air or nitrogen atmosphere, and keeping the highest temperature for 10 h to 96 h to completely remove the organic matter in the ceramic green body;

[0013] S7: placing the degreased and debinded ceramic disc in a high-temperature sintering furnace, and sintering the disc into ceramic at a temperature of 1200°C to 1700°C in any one or more protective atmospheres of N2, H2, and Ar.

[0014] Preferably, in step S1, the inorganic additive is any one of SiO2, MgO, CaO, Y2O3 or a mixture of two or more thereof.

[0015] Preferably, in step S2, the side length of the square ceramic green sheet is 200-600 mm.

[0016] The above technical solution has the following beneficial effects:

[0017] The present application can produce ceramic disks with multi-layer structures with thicknesses ranging from 2 to 10 mm by adding multiple layers of interconnected conductive layers to meet the requirements of different semiconductor devices for different thicknesses of electrostatic chuck ceramic disks;

[0018] The present application evenly distributes multiple layers of interconnected electrodes inside the ceramic disk, so that the thickness of the ceramic disk is consistent while meeting the thickness of the ceramic disk, and is not affected by the superposition of the thickness of the interconnected electrodes;

[0019] The present application evenly distributes multiple layers of interconnected electrodes inside the ceramic disk, so that when the ceramic disk is powered on, it will not generate heat due to local interconnected electrodes, resulting in uneven temperature distribution caused by heat accumulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic cross-sectional structure diagram of a method for preparing a common electrostatic chuck multilayer interconnected ceramic disk;

[0021] Figure 2 It is a schematic cross-sectional structure diagram of a method for preparing a multi-layer interconnected ceramic disk of an electrostatic chuck according to the present invention. DETAILED DESCRIPTION

[0022] 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.

[0023] The manufacturing processes involved in the preparation method of the present application mainly include: preparing ceramic slurry by ball milling, forming green sheets by tape casting, electrode screen printing, mechanical processing of positioning holes, vias, electrode holes 5, lamination of ceramic green sheets by multi-layer stacking, debinding and degreasing, and high-temperature sintering;

[0024] The ceramic slurry produced by ball milling is cast into a ceramic green sheet of a certain thickness by a casting process, and an adsorption electrode 2 and an interconnection conductive electrode 3 built into the ceramic disk are produced on the ceramic green sheet by screen printing. Positioning holes for lamination, multi-layer interconnection conductive holes 4, and electrode holes 5 are respectively produced on the ceramic green sheet by mechanical processing. The metal conductive slurry 4 is filled in the multi-layer interconnection conductive holes. After the metal electrodes, conductive interconnection electrodes, etc. inside the ceramic disk are processed and manufactured, the positioning holes are used for positioning, and the dielectric layer 1, the adsorption electrode 3, and the dielectric layer 1 are laminated by a laminating machine under certain temperature, pressure, and time conditions. 2. The interconnected conductive layer 3 and the ceramic green body with the electrode hole 5 are stacked in position, so that the green layers of the ceramic disk are tightly attached 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 electrode and the ceramic layer are multi-layered co-fired under certain temperature and atmosphere conditions to sinter the ceramic disk into porcelain, thereby producing a ceramic disk with a multi-layer interconnected structure that meets the requirements of mechanical properties and electrical properties and meets the requirements of thickness. The structure of the multi-layer interconnected ceramic disk of this application is referenced Figure 2 , the multi-layer interconnected ceramic disk structure is not limited to Figure 1 In the structure, ceramic plates of any thickness can be made by adding interconnection conductive layers; Figure 1 , which is common and simple to increase the interconnection conduction layer so that the thickness of the ceramic plate meets the requirements;

[0025] The main purpose of this application is to produce a ceramic disc with a thickness of more than 2 mm by adding multiple interconnection layers to meet the requirements of semiconductor equipment for different thicknesses of electrostatic chuck ceramic discs, and at the same time, the multi-layer interconnection electrodes of each layer are evenly placed in different positions to produce a thicker ceramic disc with a thickness of more than 2 mm with good thickness consistency, uniform temperature during use, and no local high temperature;

[0026] refer to Figure 2 The multi-layer interconnected ceramic disk includes a dielectric layer 1, an adsorption electrode layer 2, a multi-layer interconnected conductive layer 3, a metal conductive slurry 4, and an electrode hole 5. Between the multi-layer ceramic green bodies, the multi-layer interconnected conductive layers 3 are staggered from top to bottom. The preparation method of the multi-layer interconnected ceramic disk includes the following steps:

[0027] S1: Add a certain amount of ceramic powder, 6% to 15% of resin powder, 1% to 6% of plasticizer, 0.1% to 2% of dispersant, 1% to 6% of inorganic additives, and 50% to 120% of organic solvent into a ball mill according to the proportion, and mill the ball mill 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;

[0028] In other implementations of this embodiment, when preparing the organic suspended ceramic slurry, 6% or 15% of resin powder, 1% or 6% of plasticizer, 0.1% or 2% of dispersant, 1% or 6% of inorganic additive, and 50% or 120% of organic solvent are added to the ceramic powder, and added to the ball mill in proportion, and the ball mill is milled at a speed of 20pm / min or 50rpm / min for 24h or 96h, and the ball milling is completed;

[0029] In other implementations of this embodiment, when preparing the organic suspended ceramic slurry, 10% of resin powder, 3% of plasticizer, 1% of dispersant, 3% of inorganic additive, and 70% of organic solvent are added to 13% of ceramic powder, and added to a ball mill in proportion. The ball mill is milled at a speed of 35 rpm / min for 72 hours. After the ball milling is completed,

[0030] Wherein, the ceramic powder is any one of Al2O3, AlN, SiC, and Si3N4 materials, which can be selected according to needs or requirements;

[0031] S2: The organic suspended ceramic slurry is tape-casted to produce a ceramic green sheet of a certain thickness, wherein the thickness of the ceramic green sheet is 200 to 700 μm, and the thickness range of a single ceramic green sheet is within ±20 μm. The tape-casted ceramic green sheet is cut into square ceramic green sheets of a size that meets the use requirements;

[0032] In other implementations of this embodiment, the thickness of the ceramic green sheet is 200um or 700um, and the thickness range of a single ceramic green sheet is within ±20um;

[0033] S3: machining the cut ceramic green sheet into positioning holes 5, interconnection via holes, and electrode holes 5 by mechanical machining. When machining each layer of interconnection via holes, it is necessary to design the hole machining position coordinates according to the drawings, and respectively machine the interconnection via holes at the corresponding positions of each interconnection layer 3;

[0034] S4: metal conductive paste 4 is filled into the interconnection conductive holes of the machined ceramic green sheet by a hole filling method, and adsorption electrodes and interconnection conductive electrodes are respectively produced by screen printing. The thickness of the adsorption electrodes and the interconnection conductive electrodes is 5um or 20um. In other implementations of this embodiment, the thickness of the adsorption electrodes and the interconnection conductive electrodes is 12um, and the thickness range of the adsorption electrodes and the interconnection conductive electrodes is within ±0.5um. When the interconnection conductive electrodes are printed, since the positions of each layer of interconnection conductive electrodes are different, it is necessary to produce a screen printing screen that meets the requirements of different positions according to the requirements of the design drawings to ensure that each layer of interconnection conductive electrodes corresponds to the interconnection conductive holes one by one;

[0035] S5: The ceramic green sheets after the holes are filled are positioned by positioning holes according to the product construction sequence, and are stacked together by positioning and stacking using a laminating machine. During the stacking, the pressure is 50T to 500T, the temperature is 30°C to 80°C, and the time is 1min to 20min, so as to produce a green ceramic disc with a multi-layer interconnection structure, and the multi-layer interconnection conductive layer 3 is evenly distributed inside the ceramic disc;

[0036] In other implementations of this embodiment, during lamination, the pressure is 50T or 500T, the temperature is 30°C or 80°C, and the time is 1min or 20min, so as to produce a green ceramic disc with a multi-layer interconnection structure, and the multi-layer interconnection conductive layer 3 is evenly distributed inside the ceramic disc. Lamination can also be performed at a pressure of 250T, a temperature of 55°C, and a lamination time of 10min;

[0037] S6: placing the laminated green ceramic disc in a degreasing furnace, degreasing and debinding at 350°C to 550°C in an air or nitrogen atmosphere, and keeping the highest temperature for 10h to 96h, so as to remove all organic matter in the ceramic green body. In other embodiments of this embodiment, degreasing and debinding are carried out at 450°C in an air or nitrogen atmosphere, and the highest temperature is kept for 55h to remove all organic matter in the ceramic green body;

[0038] S7: placing the degreased and debinded ceramic disc in a high-temperature sintering furnace, and sintering the disc into ceramic at a temperature of 1200° C. to 1700° C. in any one or more protective atmospheres of N2, H2, and Ar. In other implementations of this embodiment, the sintering temperature is 1200° C. or 1700° C., and the sintering temperature may also be 1500° C.;

[0039] In step S1, the inorganic additive is any one of SiO2, MgO, CaO, Y2O3 or a mixture of two or more thereof; in the above step S2, the side length of the square ceramic green sheet is 200 to 600 mm, which is selected according to the needs;

[0040] The present application can produce a ceramic disk with a multi-layer structure having a thickness of 2 to 10 mm by adding a multi-layer interconnection conductive layer 3 to meet the requirements of different semiconductor devices for different thicknesses of electrostatic chuck ceramic disks;

[0041] The present application evenly distributes multiple layers of interconnected electrodes inside the ceramic disk, so that the thickness of the ceramic disk is consistent while meeting the thickness of the ceramic disk, and is not affected by the superposition of the thickness of the interconnected electrodes;

[0042] The present application evenly distributes multiple layers of interconnected electrodes inside the ceramic disk, so that when the ceramic disk is powered on, it will not generate heat due to local interconnected electrodes, resulting in uneven temperature distribution caused by heat accumulation.

[0043] 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 interconnected ceramic disc of an electrostatic chuck, characterized in that: The multi-layer interconnected ceramic disk comprises a dielectric layer, an adsorption electrode layer, a plurality of multi-layer interconnected conductive layers, a metal conductive slurry, and an electrode hole, wherein the plurality of multi-layer interconnected conductive layers are staggered with each other. The preparation method of the multi-layer interconnected ceramic disk comprises the following steps: S1: Add a certain amount of ceramic powder, which is any one of Al2O3, AlN, SiC, and Si3N4 materials, 6% to 15% of resin powder, 1% to 6% of plasticizer, 0.1% to 2% of dispersant, 1% to 6% of inorganic additives, and 50% to 120% of organic solvent into a ball mill in proportion, and mill the ball mill 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; S2: The organic suspended ceramic slurry is tape-casted to produce a ceramic green sheet of a certain thickness, wherein the thickness of the ceramic green sheet is 200 to 700 μm, and the thickness range of a single ceramic green sheet is within ±20 μm. 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 via holes, and electrode holes from the cut ceramic green sheets by mechanical processing. When machining each layer of interconnection via holes, it is necessary to design the hole machining position coordinates according to the drawings, and machine the interconnection via holes at the corresponding positions of each interconnection layer; S4: metal conductive slurry is filled into the interconnection conductive holes of the machined ceramic green sheet by a hole filling method, and adsorption electrodes and interconnection conductive electrodes are respectively produced by a screen printing method. The thickness of the adsorption electrodes and the interconnection conductive electrodes is 5 to 20 um, and the thickness range of the adsorption electrodes and the interconnection conductive electrodes is within ±0.5 um. When the interconnection conductive electrodes are printed, since the positions of each layer of interconnection conductive electrodes are different, it is necessary to produce a screen printing screen that meets the requirements of different positions according to the requirements of the design drawings to ensure that each layer of interconnection conductive electrodes corresponds to the interconnection conductive holes one by one; S5: The ceramic green sheets after the holes are filled are positioned by positioning holes according to the product construction sequence, and are stacked together by positioning and stacking using a stacking machine. During the stacking, the pressure is 50T to 500T, the temperature is 30℃ to 80℃, and the time is 1min to 20min, so as to produce a green ceramic disc with a multi-layer interconnection structure, and the multi-layer interconnection conductive layer is evenly distributed inside the ceramic disc; S6: placing the laminated green ceramic disc in a degreasing furnace, degreasing and debinding at 350° C. to 550° C. in an air or nitrogen atmosphere, and keeping the highest temperature for 10 h to 96 h to completely remove the organic matter in the ceramic green body; S7: placing the degreased and debinded ceramic disc in a high-temperature sintering furnace, and sintering the disc into ceramic at a temperature of 1200°C to 1700°C in any one or more protective atmospheres of N2, H2, and Ar.

2. The method for preparing a multi-layer interconnected ceramic disc of an electrostatic chuck according to claim 1, characterized in that: In the step S1, the inorganic additive is any one of SiO2, MgO, CaO, Y2O3 or a mixture of two or more thereof.

3. The method for preparing a multi-layer interconnected ceramic disc for an electrostatic chuck according to claim 1, characterized in that: In the step S2, the side length of the square ceramic green sheet is 200-600 mm.

Images