Preparation method of electrode slurry for electrostatic chuck

Abstract

The invention discloses a preparation method of electrode slurry for an electrostatic chuck, and belongs to the technical field of electrostatic chucks, powder is dispersed in an organic solvent through a ball mill, the powder is aluminum oxide powder and two or more kinds of carbide powder with different particle sizes, the D50 particle size of the aluminum oxide powder is 3-6 [mu] m, and the D50 particle size of the carbide powder is 3-6 [mu] m; powder with different particle sizes can have higher stacking density, few organic solvents are needed in the dispersion process, shrinkage after sintering is small, and cracking and layering of electrode slurry are not prone to being caused; ball-milling and dispersing the powder, drying in a drying oven for 24 hours, grinding by using a mortar, and sieving for later use; and mixing the sieved powder with an organic carrier with the solid content of 60-80%, mixing for 30-60 minutes in a mixing and kneading machine, and then rolling in a three-roller machine to obtain the required electrode slurry. According to the invention, three kinds of particles with different particle sizes are mixed, so that the powder bulk density is greatly improved, the electrode thickness controllability is improved, and the shrinkage ratio after burning is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of electrostatic chucks, and in particular to a method for preparing electrode slurry for electrostatic chucks. Background Art

[0002] The conductive particles of electrostatic chuck electrode slurry are usually metal particles such as W and Mo. The advantage is that the conductivity is good, but there are the following defects:

[0003] 1. The bonding strength between the electrode layer and the ceramic layer is poor, and delamination and cracking are prone to occur after sintering shrinkage;

[0004] 2. The metal particles will react with the carbon elements in the ceramic plate to produce carbonization, resulting in changes in resistivity and unstable adsorption;

[0005] 3. Metal electrodes are easily oxidized.

[0006] In addition to the influence of conductive particles, the particle size of the electrode slurry powder will also have a great impact on the electrode slurry. Using powders with similar particle sizes will have a lower packing density and a large shrinkage ratio after sintering, resulting in a large gap between the printed thickness and the thickness of the electrode after sintering, making the thickness difficult to control. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method for preparing electrode slurry for an electrostatic chuck, so as to solve the problem raised in the background technology.

[0008] In order to solve the above technical problems, the technical solution of the present invention is:

[0009] A method for preparing an electrode slurry for an electrostatic chuck, the method comprising the following steps:

[0010] Dispersing the powder in an organic solvent by a ball mill, wherein the powder is alumina powder and two or more carbide powders with different particle sizes, the D50 particle size of the alumina powder is 3 to 6 μm, the powders with different particle sizes can have a higher packing density, less organic solvent is required during the dispersion process, the shrinkage after sintering is relatively small, and it is not easy to cause cracking and stratification of the electrode slurry;

[0011] The powder is dispersed by ball milling and then dried in an oven for 24 hours. It is ground and sieved in a mortar for later use.

[0012] The sieved powder is mixed with an organic carrier with a solid content of 60-80%, mixed in a crusher for 30-60 minutes, and then rolled in a three-roller mill to obtain the desired electrode slurry.

[0013] Preferably, the D50 particle size of the alumina powder is 4 to 5 μm, and the D50 particle size of the carbide powder is 1 to 3 μm.

[0014] Preferably, the organic solvent is any one of ethanol, toluene and n-butanol.

[0015] Preferably, the ball milling time is 5 to 12 hours.

[0016] Preferably, the solid content of the sieved powder after mixing with the organic carrier is 70-75%.

[0017] Preferably, the carbide powder is tungsten carbide powder.

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

[0019] 1. The use of three different particle size particles mixed to greatly increase the powder packing density, improve the controllability of electrode thickness and reduce the post-firing shrinkage ratio;

[0020] 2. Use carbides to replace metal particles, effectively improving the matching between the electrode layer and the ceramic plate, reducing oxidation, and stabilizing adsorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a diagram showing the stacking effect of three powder particles with different particle sizes used in the present invention;

[0022] Figure 2 This is a diagram showing the stacking effect of powder particles with the same particle size used in the present invention. 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] Example 1

[0025] A method for preparing an electrode slurry for an electrostatic chuck comprises the following steps:

[0026] The powder is dispersed in an organic solvent by a ball mill. The powder is selected from 3-6 μm alumina powder, preferably 4-5 μm, and two carbide powders with different particle sizes, with a particle size range of 1-3 μm. Figure 1 The mixing of three powders with different particle sizes can have a higher packing density, less organic solvent is required during the dispersion process, the shrinkage after sintering is relatively small, and it is not easy to cause cracking and stratification of the electrode slurry. Figure 2The packing density of the powder particles with the same particle size is lower than that of the mixture of three powders with different particle sizes, and stratification and cracking are prone to occur; wherein the organic solvent can be ethanol, toluene, n-butanol, etc., preferably ethanol, the ball milling time is 5 to 12 hours, preferably 8 to 10 hours, and the powder is dried in an oven for 24 hours after ball milling, and ground and sieved in a mortar for subsequent use;

[0027] The sieved powder is mixed with an organic carrier with a solid content of 60-80%, preferably 70-75%, mixed in a crusher for 30-60 minutes, and then rolled in a three-roll mill to obtain the desired electrode slurry;

[0028] The preparation method of the electrode slurry for the electrostatic chuck of the present application adopts metal carbides to replace metal elements as the conductive particles of the electrode slurry. The chemical properties of carbides are relatively stable, the oxidation temperature is higher than that of metal particles, and they are not affected by carbonization, and can maintain adsorption force. The conductivity of carbides can meet the conductivity requirements of the electrode slurry for the electrostatic chuck.

[0029] The electrode slurry for the electrostatic chuck of the present application uses three or more powders with different particle sizes to increase the packing density, reduce the post-firing shrinkage ratio, and improve the controllability of the thickness of the electrode slurry for the electrostatic chuck.

[0030] Example 2

[0031] A method for preparing an electrode slurry for an electrostatic chuck comprises the following steps:

[0032] The powders were dispersed in an organic solvent by a ball mill. The powders were 3 μm alumina powder and two carbide powders with different particle sizes, each with a particle size of 1 μm. Figure 1 The mixing of three powders with different particle sizes can have a higher packing density, less organic solvent is required during the dispersion process, the shrinkage after sintering is relatively small, and it is not easy to cause cracking and stratification of the electrode slurry. Figure 2 The packing density of the powder particles with the same particle size is lower than that of the mixture of three powders with different particle sizes, which is prone to stratification and cracking; wherein the organic solvent can be ethanol, toluene, n-butanol, etc., preferably ethanol, the ball milling time is 5h, and the powder is dried in an oven for 24h after ball milling, and ground and sieved with a mortar for subsequent use;

[0033] The sieved powder was mixed with an organic carrier with a solid content of 60%, mixed in a crusher for 30 minutes, and then rolled in a three-roll mill to obtain the desired electrode slurry.

[0034] Example 3

[0035] A method for preparing an electrode slurry for an electrostatic chuck comprises the following steps:

[0036] The powders were dispersed in an organic solvent by a ball mill. The powders were 6 μm alumina powder and two carbide powders with different particle sizes, with a particle size of 3 μm. Figure 1 The mixing of three powders with different particle sizes can have a higher packing density, less organic solvent is required during the dispersion process, the shrinkage after sintering is relatively small, and it is not easy to cause cracking and stratification of the electrode slurry. Figure 2 The packing density of the powder particles with the same particle size is lower than that of the mixture of three powders with different particle sizes, which is prone to stratification and cracking; wherein the organic solvent can be ethanol, toluene, n-butanol, etc., preferably ethanol, the ball milling time is 12h, preferably 10h, and the powder is dried in an oven for 24h after ball milling, and ground and sieved with a mortar for subsequent use;

[0037] The sieved powder was mixed with an organic carrier with a solid content of 80%, mixed in a crusher for 60 minutes, and then rolled in a three-roll mill to obtain the desired electrode slurry.

[0038] Embodiment 4: A method for preparing an electrode slurry for an electrostatic chuck, comprising the following steps:

[0039] Step 1: Select alumina powder with a D50 of 4 μm, tungsten carbide powder with a D50 of 2 μm and 1 μm respectively, mix them with ethanol, and disperse and mix them in a ball mill for 10 hours;

[0040] Step 2: After ball milling, dry in an oven at 80°C for 24 hours, grind and crush using an agate mortar, and then sieve to obtain a mixed and dispersed powder;

[0041] Step 3: Mix the powder with the organic carrier, with a solid content of 73%, and mix in a crusher for 50 minutes after a preliminary simple mixing;

[0042] Step 4: transfer the crushed slurry into a three-roll mill and grind it 5 to 7 times, adjusting the number of times of grinding according to the viscosity and fineness to obtain tungsten carbide electrode slurry;

[0043] Comparative Example 1:

[0044] Step 1: Select alumina powder with a D50 of 4 μm and tungsten carbide powder with a D50 of 4 μm, mix them with ethanol, and disperse and mix them in a ball mill for 10 hours;

[0045] Step 2: After ball milling, dry in an oven at 80°C for 24 hours, grind and crush using an agate mortar, and then sieve to obtain a mixed and dispersed powder;

[0046] Step 3: Mix the powder with the organic carrier, with a solid content of 73%, and mix in a crusher for 50 minutes after a preliminary simple mixing;

[0047] Step 4: Transfer the crushed slurry into a three-roll mill and grind it 5 to 7 times. Adjust the number of grinding times according to the viscosity and fineness to obtain tungsten carbide electrode slurry.

[0048] Comparative Example 2:

[0049] Step 1: Select alumina powder with a D50 of 4 μm and tungsten carbide powder with a D50 of 4 μm, mix them with ethanol, and disperse and mix them in a ball mill for 10 hours;

[0050] Step 2: After ball milling, dry in an oven at 80°C for 24 hours, grind and crush using an agate mortar, and then sieve to obtain a mixed and dispersed powder;

[0051] Step 3: Mix the powder with the organic carrier, with a solid content of 73%, and mix in a crusher for 50 minutes after a preliminary simple mixing;

[0052] Step 4: Transfer the crushed slurry into a three-roll mill and grind it 5 to 7 times. Adjust the number of grinding times according to the viscosity and fineness to obtain tungsten carbide electrode slurry.

[0053] The thickness of the electrode slurries obtained in the above Example 1, Comparative Example 1 and Comparative Example 2 before and after sintering and the cracking and delamination phenomena are shown in Table 1 below;

[0054] Table 1:

[0055] Trial plan Printed electrode thickness Electrode thickness after burning Cracking and delamination Example 4 20μm 18μm No cracking or delamination Comparative Example 1 20μm 14μm Cracking Comparative Example 2 20μm 16μm Slight cracking

[0056] As can be seen from Table 1, compared with Comparative Examples 1 and 2, the thickness of the electrode in Example 4, which includes aluminum oxide powder, 2μm tungsten carbide powder and 1μm electrostatic chuck electrode slurry, reaches 18μm after firing, and there is no cracking and delamination, and the printed electrode thickness shrinks relatively little after firing.

[0057] 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.

[0058] 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 an electrode slurry for an electrostatic chuck, characterized in that: The preparation method comprises the following steps: Dispersing the powder in an organic solvent by a ball mill, wherein the powder is alumina powder and two or more carbide powders with different particle sizes, the D50 particle size of the alumina powder is 3 to 6 μm, the powders with different particle sizes can have a higher packing density, less organic solvent is required during the dispersion process, the shrinkage after sintering is relatively small, and it is not easy to cause cracking and stratification of the electrode slurry; The powder is dispersed by ball milling and then dried in an oven for 24 hours. It is ground and sieved in a mortar for later use. The sieved powder is mixed with an organic carrier with a solid content of 60-80%, mixed in a crusher for 30-60 minutes, and then rolled in a three-roller mill to obtain the desired electrode slurry.

2. The method for preparing an electrode slurry for an electrostatic chuck according to claim 1, characterized in that: The D50 particle size of the alumina powder is 4 to 5 μm, and the D50 particle size of the carbide powder is 1 to 3 μm.

3. The method for preparing an electrode slurry for an electrostatic chuck according to claim 1, characterized in that: The organic solvent is any one of ethanol, toluene and n-butanol.

4. The method for preparing an electrode slurry for an electrostatic chuck according to claim 3, characterized in that: The ball milling time is 5 to 12 hours.

5. The method for preparing an electrode slurry for an electrostatic chuck according to claim 1, characterized in that: The solid content of the sieved powder after mixing with the organic carrier is 70-75%.

6. The method for preparing an electrode slurry for an electrostatic chuck according to claim 1, characterized in that: The carbide powder is tungsten carbide powder.

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