Electrostatic chuck ceramic plate dry-pressing method

Abstract

The application discloses a kind of electrostatic chuck ceramic plate dry pressing forming methods, belong to electrostatic chuck technical field, comprising: S1: after the ceramic powder needed weight of medium layer is laid, heat pressing is carried out, and first ceramic forming body is obtained;S2: after the ceramic powder needed weight half of lower medium layer is laid, heat pressing is carried out, and second ceramic forming body is obtained;S3: after the ceramic powder needed weight half of lower medium layer is laid, heat pressing is carried out, and third ceramic forming body is obtained;S4: first ceramic forming body, third ceramic forming body carries out single side grinding, and second ceramic forming body is double side ground;S5: first ceramic forming body, second ceramic forming body, third ceramic forming body is according to requirement and is opened hole;S6: the hole position of three forming bodies is aligned, and heat pressing is sintered.The forming method can avoid the problem of glue removal, reduce the problem of inaccurate positioning, prevent the problem of subsequent processing damage electrode, compared with prior art, its process flow is shorter, and control point is less.

Description

Technical Field

[0001] The invention relates to the technical field of electrostatic chucks, in particular to a dry pressing method for an electrostatic chuck ceramic plate. Background Art

[0002] There are two methods for forming green parts for electrostatic chucks: tape casting and dry pressing. The tape casting process includes batching, ball milling, discharging, degassing, tape casting, lamination, printing, hot pressing, punching, binder removal, and hot pressing sintering. The tape casting process has many steps and many control points, making the entire process more complicated. The dry pressing process includes batching, ball milling, discharging, hot pressing, punching, binder removal, and hot pressing sintering. The dry pressing process is shorter and has relatively fewer control points. Therefore, a method for forming electrostatic chuck ceramics with a shorter process and fewer control points is needed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a dry pressing forming method for an electrostatic chuck ceramic plate, which has a short process flow, fewer control points, improves positioning accuracy, and prevents subsequent processing from damaging the electrode.

[0004] In order to solve the above technical problems, the technical solution of the present invention is:

[0005] A dry pressing method for an electrostatic chuck ceramic plate, the forming method comprising:

[0006] S1: Applying BN as a release agent on the upper dielectric layer mold, covering it with the required weight of ceramic powder for the upper dielectric layer, and then hot pressing to obtain a first ceramic formed body after hot pressing. The first ceramic formed body is polygonal;

[0007] S2: Applying BN as a release agent on the lower dielectric layer mold, covering it with half the weight of ceramic powder required for the lower dielectric layer, and then hot pressing to obtain a second ceramic formed body. The second ceramic formed body has a polygonal structure of the same size as the first ceramic formed body.

[0008] S3: Applying BN as a release agent on the lower dielectric layer mold, covering it with half the weight of ceramic powder required for the lower dielectric layer, and then hot pressing to obtain a third ceramic formed body. The third ceramic formed body has a polygonal structure of the same size as the second ceramic formed body.

[0009] S4: After hot pressing, the first ceramic formed body, the second ceramic formed body, and the third ceramic formed body are all ground. The first ceramic formed body and the third ceramic formed body are ground on one side, and the second ceramic formed body is ground on both sides. During sintering, the second ceramic formed body is located between the first ceramic formed body and the second ceramic formed body, and the first ceramic formed body and the third ceramic formed body are both with their ground sides facing the second ceramic formed body. The first ceramic formed body is located above the second ceramic formed body, and the third ceramic formed body is located below the second ceramic formed body.

[0010] S5: The first ceramic formed body is provided with a first pin hole, which is a blind hole. The first pin hole is opened on the side of the first ceramic formed body that has not been ground. The size of the first pin hole is 60% to 80% of its final size. The first pin hole is filled with BN. The first ceramic formed body is also provided with a first groove whose size is consistent with the size of the electrode mesh. The first groove is provided on the side of the first ceramic formed body that has been ground. The depth of the first groove is half the thickness of the electrode mesh.

[0011] The second ceramic formed body is provided with a second pin hole and a first electrode hole, the second pin hole is a blind hole, and is filled with BN, the size of the second pin hole is 60% to 80% of its final size, the central axis of the second pin hole coincides with the central axis of the first pin hole, the first electrode hole is a blind hole, and is filled with WC, the size of the first electrode hole is 60% to 80% of its final size, the second ceramic formed body is further provided with a second groove having a size consistent with the size of the electrode mesh, the second groove is arranged on the side facing the first groove, the size of the second groove is the same as the size of the first groove, and the depth of the second groove is half the thickness of the electrode mesh, and when the second ceramic formed body is bonded and sintered with the first ceramic formed body, the edge of the first groove is aligned with the edge of the second groove;

[0012] The third ceramic formed body is provided with a third pin hole and a second electrode hole, the third pin hole being a blind hole and filled with BN, and the size of the third pin hole being 60% to 80% of its final size, the third pin hole being arranged on a side of the third ceramic formed body away from the second ceramic formed body, and when the third ceramic formed body and the second ceramic formed body are bonded and sintered, the central axis of the first pin hole coincides with the central axis of the second pin hole, the second electrode hole being a blind hole and filled with WC, and the second electrode hole being 60% to 80% of its final size, and when the third ceramic formed body and the second ceramic formed body are bonded and sintered, the central axis of the second electrode hole coincides with the central axis of the first electrode hole;

[0013] S6: Place the second ceramic formed body with the ground side of the third ceramic formed body facing upwards, align the second pin hole with the third pin hole, align the first electrode hole with the second electrode hole, place the electrode mesh in the second groove, and then place the first ceramic formed body, align the center line of the first pin hole with the center line of the second pin hole. After the first, second and third ceramic formed bodies are stacked, place them back into the hot pressing mold and sinter them under hot pressing.

[0014] Preferably, the pressure during hot pressing in S1, S2 and S3 is 5-15 MPA, the temperature of hot pressing is 1200-1500° C., and the first ceramic formed body, the second ceramic formed body and the third ceramic formed body are obtained after hot pressing.

[0015] Preferably, in said S4, the flatness of the surface of the first ceramic formed body, the second ceramic formed body, and the third ceramic formed body after grinding is less than 20 microns, and the surface roughness is less than 6 microns.

[0016] Preferably, the pressure in the hot pressing mold in S6 is 5-30 MPa, and the temperature of hot pressing sintering is 1600-2100°C.

[0017] The above technical solution has the following beneficial effects:

[0018] By first hot-pressing the first, second, and third ceramic molded bodies, and then stacking the three and hot-pressing and sintering them, the problem of debonding can be avoided. The first, second, and third ceramic molded bodies are processed with their own holes respectively, which reduces the problem of inaccurate positioning and prevents the problem of subsequent processing damaging the electrodes. Compared with the existing technology, the process flow is shorter and the control points are fewer. DETAILED DESCRIPTION

[0019] The following is a further description of specific embodiments of the present invention. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and 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 may be combined with each other as long as they do not conflict with each other.

[0020] The dry pressing method for an electrostatic chuck ceramic plate comprises the following steps:

[0021] S1: Applying BN (boron nitride) as a release agent on the upper dielectric layer mold, and then covering it with the required weight of ceramic powder for the upper dielectric layer, and then hot pressing is performed. The pressure during hot pressing is 5 MPa, and the hot pressing temperature is 1200° C. In other implementations of this embodiment, the pressure during hot pressing can also be 15 MPa, and the hot pressing temperature can also be 1500° C. After hot pressing, a first ceramic formed body, a second ceramic formed body, and a third ceramic formed body are obtained. After hot pressing, the first ceramic formed body is obtained, and the first ceramic formed body is polygonal.

[0022] S2: Applying boron nitride (BN) as a release agent on the mold for the lower dielectric layer, and then covering it with half the weight of ceramic powder required for the lower dielectric layer, and then hot pressing is performed. The pressure during hot pressing is 5 MPa and the temperature during hot pressing is 1200° C. In other embodiments of this embodiment, the pressure during hot pressing can also be 15 MPa and the temperature during hot pressing can also be 1500° C. to obtain a second ceramic formed body. The second ceramic formed body is a polygonal structure of the same size as the first ceramic formed body.

[0023] S3: Applying boron nitride (BN) as a release agent on the mold for the lower dielectric layer, and then covering it with half the weight of ceramic powder required for the lower dielectric layer, and then hot pressing is performed. The pressure during hot pressing is 5 MPa and the temperature during hot pressing is 1200° C. In other embodiments of this embodiment, the pressure during hot pressing can also be 15 MPa and the temperature during hot pressing can also be 1500° C. to obtain a third ceramic formed body. The third ceramic formed body is a polygonal structure of the same size as the second ceramic formed body.

[0024] The first ceramic formed body, the second ceramic formed body, and the third ceramic formed body all have the same multi-deformed shape, which can be a hexagon or a dodecagon, or an octagon or a decagon. The three are all arranged into polygons. On the one hand, it is convenient for the three to be superimposed during the final sintering so that the hole positions of their respective corresponding holes can be aligned, which also facilitates the alignment of the first ceramic formed body, the second ceramic formed body, and the third ceramic formed body. In addition, since the final electrostatic chuck ceramic plate needs to be processed into a disc shape, less part is removed when processing the polygonal structure into a circular structure;

[0025] S4: After hot pressing, the first ceramic formed body, the second ceramic formed body, and the third ceramic formed body are all ground. The first ceramic formed body and the third ceramic formed body are ground on one side, and the second ceramic formed body is ground on both sides. During sintering, the second ceramic formed body is located between the first ceramic formed body and the second ceramic formed body, and the ground side of the first ceramic formed body and the third ceramic formed body are both facing the second ceramic formed body. The first ceramic formed body is located above the second ceramic formed body, and the third ceramic formed body is located below the second ceramic formed body.

[0026] The flatness of the surface of the first, second, and third ceramic formed bodies after grinding is less than 20 microns, and the surface roughness is less than 6 microns, so as to ensure the surface quality of the ground surfaces and make the three bodies better sintered together after bonding, thereby ensuring the sintering quality;

[0027] S5: A first pin hole is provided on the first ceramic formed body. The first pin hole is a blind hole and is opened on the side of the first ceramic formed body that has not been ground. The size of the first pin hole is 60% of its final size. In other implementations of this embodiment, the size of the first pin hole can also be 80% of its final size. The first pin hole is filled with BN. The first ceramic formed body is also provided with a first groove having a size consistent with that of the electrode mesh. The first groove is provided on the side of the first ceramic formed body that has been ground. The depth of the first groove is half the thickness of the electrode mesh.

[0028] The second ceramic formed body is provided with a second pin hole and a first electrode hole, the second pin hole is a blind hole, and is filled with BN. The size of the second pin hole is 60% of its final size. In other embodiments of this embodiment, the size of the second pin hole may also be 80% of its final size. The central axis of the second pin hole coincides with the central axis of the first pin hole. The first electrode hole is a blind hole, and is filled with WC, which is tungsten carbide. The size of the first electrode hole is 60% of its final size. In other embodiments of this embodiment, the size of the first electrode hole may also be 80% of its final size. The second ceramic formed body is further provided with a second groove having a size consistent with that of the electrode mesh. The second groove is provided on the side facing the first groove, has the same size as that of the first groove, and has a depth of half the thickness of the electrode mesh. When the second ceramic formed body and the first ceramic formed body are bonded and sintered, the edge of the first groove is aligned with the edge of the second groove.

[0029] The third ceramic forming body is provided with a third pin hole and a second electrode hole. The third pin hole is a blind hole, BN is filled in the third pin hole, and the size of the third pin hole is 60% of the final size. In other embodiments of the present embodiment, the size of the third pin hole can also be 80% of the final size. The third pin hole is arranged on the side of the third ceramic forming body away from the second ceramic forming body. When the third ceramic forming body is sintered in combination with the second ceramic forming body, the center axis of the first pin hole coincides with the center axis of the second pin hole. The second electrode hole is a blind hole, and WC is filled in the second electrode hole. WC is tungsten carbide. The size of the second electrode hole is 60% of the final size. In other embodiments of the present embodiment, the size of the second electrode hole can also be 80% of the final size. When the third ceramic forming body is sintered in combination with the second ceramic forming body, the center axis of the second electrode hole coincides with the center axis of the first electrode hole.

[0030] After the first ceramic forming body, the second ceramic forming body, and the third ceramic forming body are stacked together, the center lines of the first pin hole, the second pin hole, and the third pin hole coincide. The first pin hole, the second pin hole, and the third pin hole are each 60% to 80% of their respective final sizes, leaving a final processing allowance. Finally, the first pin hole, the second pin hole, and the third pin hole are punched through to form the final pin hole, i.e., the ejector pin hole. The processing allowance of the process can ensure the quality of the ejector pin hole.

[0031] Similarly, after the first electrode hole and the second electrode hole are combined in the second ceramic forming body and the third ceramic forming body, the center axes of the two holes are aligned, and the diameters of the two holes are each 60% to 80% of the final diameter, leaving a processing allowance for later processing to ensure the quality and consistency of the final hole.

[0032] S6: Place the second ceramic forming body with the ground side of the third ceramic forming body facing up, and align the second pin hole with the third pin hole and the first electrode hole with the second electrode hole. Place the electrode mesh in the second groove, and then place the first ceramic forming body with the center line of the first pin hole aligned with the center line of the second pin hole. After the first ceramic forming body, the second ceramic forming body, and the third ceramic forming body are combined, they are re-placed in the hot pressing mold. The pressure in the hot pressing mold is 5MPA. In other embodiments of the present embodiment, the pressure in the hot pressing mold at this time can be 30MPA. After being placed in the hot pressing mold, hot pressing sintering is performed. The temperature of the hot pressing sintering is 1600℃. In other embodiments of the present embodiment, the temperature of the hot pressing sintering can also be 2100℃.

[0033] By first hot-pressing the first ceramic formed body, the second ceramic formed body, and the third ceramic formed body, and then stacking the three and hot-pressing and sintering them, the problem of debinding can be avoided. The first ceramic formed body, the second ceramic formed body, and the third ceramic formed body are respectively processed with their own holes, which reduces the problem of inaccurate positioning and prevents the problem of subsequent processing damaging the electrode. Compared with the existing technology, its process flow is shorter and has fewer control points, which can better control the processing quality of the electrostatic chuck ceramic plate, reduce the production cost of the electrostatic chuck ceramic plate, and improve production efficiency.

[0034] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations of these embodiments may be made without departing from the principles and spirit of the present invention, and the changes still fall within the scope of protection of the present invention.

Claims

1. A method for dry pressing a ceramic plate of an electrostatic chuck, characterized in that: The molding method comprises: S1: Applying BN as a release agent on the upper dielectric layer mold, covering it with the required weight of ceramic powder for the upper dielectric layer, and then hot pressing to obtain a first ceramic formed body after hot pressing. The first ceramic formed body is polygonal; S2: Applying BN as a release agent on the lower dielectric layer mold, covering it with half the weight of ceramic powder required for the lower dielectric layer, and then hot pressing to obtain a second ceramic formed body. The second ceramic formed body has a polygonal structure of the same size as the first ceramic formed body. S3: Applying BN as a release agent on the lower dielectric layer mold, covering it with half the weight of ceramic powder required for the lower dielectric layer, and then hot pressing to obtain a third ceramic formed body. The third ceramic formed body has a polygonal structure of the same size as the second ceramic formed body. S4: After hot pressing, the first ceramic formed body, the second ceramic formed body, and the third ceramic formed body are all ground. The first ceramic formed body and the third ceramic formed body are ground on one side, and the second ceramic formed body is ground on both sides. During sintering, the second ceramic formed body is located between the first ceramic formed body and the second ceramic formed body, and the first ceramic formed body and the third ceramic formed body are both with their ground sides facing the second ceramic formed body. The first ceramic formed body is located above the second ceramic formed body, and the third ceramic formed body is located below the second ceramic formed body. S5: The first ceramic formed body is provided with a first pin hole, which is a blind hole. The first pin hole is opened on the side of the first ceramic formed body that has not been ground. The size of the first pin hole is 60% to 80% of its final size. The first pin hole is filled with BN. The first ceramic formed body is also provided with a first groove whose size is consistent with the size of the electrode mesh. The first groove is provided on the side of the first ceramic formed body that has been ground. The depth of the first groove is half the thickness of the electrode mesh. The second ceramic formed body is provided with a second pin hole and a first electrode hole, the second pin hole is a blind hole, and is filled with BN, the size of the second pin hole is 60% to 80% of its final size, the central axis of the second pin hole coincides with the central axis of the first pin hole, the first electrode hole is a blind hole, and is filled with WC, the size of the first electrode hole is 60% to 80% of its final size, the second ceramic formed body is further provided with a second groove having a size consistent with the size of the electrode mesh, the second groove is arranged on the side facing the first groove, the size of the second groove is the same as the size of the first groove, and the depth of the second groove is half the thickness of the electrode mesh, and when the second ceramic formed body is bonded and sintered with the first ceramic formed body, the edge of the first groove is aligned with the edge of the second groove; The third ceramic formed body is provided with a third pin hole and a second electrode hole, the third pin hole being a blind hole and filled with BN, and the size of the third pin hole being 60% to 80% of its final size, the third pin hole being arranged on a side of the third ceramic formed body away from the second ceramic formed body, and when the third ceramic formed body and the second ceramic formed body are bonded and sintered, the central axis of the first pin hole coincides with the central axis of the second pin hole, the second electrode hole being a blind hole and filled with WC, and the second electrode hole being 60% to 80% of its final size, and when the third ceramic formed body and the second ceramic formed body are bonded and sintered, the central axis of the second electrode hole coincides with the central axis of the first electrode hole; S6: Place the second ceramic formed body with the ground side of the third ceramic formed body facing upwards, align the second pin hole with the third pin hole, align the first electrode hole with the second electrode hole, place the electrode mesh in the second groove, and then place the first ceramic formed body, align the center line of the first pin hole with the center line of the second pin hole. After the first, second and third ceramic formed bodies are stacked, place them back into the hot pressing mold and sinter them under hot pressing.

2. The dry pressing method for an electrostatic chuck ceramic plate according to claim 1, characterized in that: The pressure during hot pressing in S1, S2 and S3 is 5-15 MPa, and the temperature of hot pressing is 1200-1500° C. After hot pressing, a first ceramic formed body, a second ceramic formed body and a third ceramic formed body are obtained.

3. The dry pressing method for an electrostatic chuck ceramic plate according to claim 1, characterized in that: In the S4, the flatness of the surfaces of the first ceramic formed body, the second ceramic formed body, and the third ceramic formed body after grinding is less than 20 microns, and the surface roughness is less than 6 microns.

4. The dry pressing method for an electrostatic chuck ceramic plate according to claim 1, characterized in that: The pressure in the hot pressing mold in S6 is 5-30 MPa, and the temperature of hot pressing sintering is 1600-2100°C.