A new method of laminating ceramic disc green bodies

Abstract

The application provides a new ceramic disc green body lamination method, comprising the following steps: fixing a plurality of ceramic green bodies through positioning pins and stacking them together; taking out the positioning pins in the stacked ceramic green bodies, injecting wax liquid into the cavity formed by the positioning holes, and obtaining a lamination structure after the wax liquid solidifies; and performing isostatic pressing on the lamination structure. The method provided by the application can ensure that the lamination green body does not displace, greatly reduces the problems of glass breakage during isostatic pressing and water leakage of plastic packaging bags, greatly improves the yield of ceramic green bodies, and reduces the labor cost and time cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrostatic chuck, in particular to a new method for laminating ceramic green bodies. BACKGROUND

[0002] Electrostatic chuck (ESC) is widely used in semiconductor wafer etching, optics and other fields. The ceramic plate made of different materials has strong pertinence to the ESC product. With the development of production technology, the requirements for high-end chips are becoming higher and higher, and various performance indicators of ceramic plates are becoming more and more stringent. At the same time, the electrostatic chuck will be continuously corroded and worn during use, so a new ceramic plate needs to be replaced every certain period of time. As a consumable, the green body before sintering is a single body multilayer laminated, and finally obtained by isostatic pressing.

[0003] In the prior art, the green body lamination method generally punches a positioning hole on each batch of body, and a positioning pin is placed in the positioning hole to fix the position of the green body lamination. When the green body lamination is good, it needs to be placed in a plastic bag for vacuum packaging. Since the ceramic green body before sintering is relatively soft, the body is easily displaced during vacuum extraction by simply fixing the positioning pin on the body, resulting in the green body being scrapped after isostatic pressing. Moreover, the green body lamination contains a positioning pin, and the glass is unevenly stressed during isostatic pressing, which can easily cause the glass to break and the green body to leak water, thereby increasing the labor cost and time cost. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a new method for laminating ceramic green bodies, which can greatly improve the yield of ceramic green bodies and reduce labor cost and time cost.

[0005] The present application provides a new method for laminating ceramic green bodies, comprising:

[0006] Fixing and stacking a plurality of ceramic green bodies together by positioning pins;

[0007] Removing the positioning pins from the stacked ceramic green bodies, injecting wax liquid into the cavity formed by the positioning hole, and obtaining a laminated structure after the wax liquid solidifies;

[0008] Isostatic pressing the laminated structure.

[0009] In the embodiments of the present application, the new method for laminating ceramic green bodies is used in the process of preparing ceramic plates for electrostatic chuck, in which a plurality of ceramic green bodies are stacked together for isostatic pressing. Those skilled in the art can set the ceramic plates for electrostatic chuck and the ceramic green bodies and the stacking structure of the ceramic green bodies in the process of preparing the ceramic plates according to the well-known technology in the art.

[0010] In the embodiment of the present application, the shape of the ceramic green body can be circular; the diameter of the ceramic green body can be selected from 280-320 mm, such as 290 mm, 300 mm, 310 mm; the thickness of the ceramic green body can be selected from 0.4-0.5 mm, such as 0.42 mm, 0.44 mm, 0.45 mm, 0.46 mm, 0.48 mm; and the composition of the ceramic green body can include alumina.

[0011] In the embodiment of the present application, the method for preparing the ceramic green body is not particularly limited, and the ceramic green body can be prepared according to actual needs by using a method well known in the art, such as a raw material tape slicing method, a laser drilling method, or an electrode printing method.

[0012] In the embodiment of the present application, the plurality of ceramic green bodies can be arranged according to the ceramic structure of the electrostatic chuck obtained in advance; for example, 5-12 ceramic green bodies can be stacked, or 6, 7, 8, 9, 10, or 11 ceramic green bodies can be stacked; and the thickness of the stacked ceramic green bodies can be selected from 4-5 mm, such as 4.2 mm, 4.4 mm, 4.5 mm, 4.6 mm, or 4.8 mm.

[0013] In the embodiment of the present application, the composition, structure size, and stacking order of the ceramic green bodies can be arranged according to the structure of the ceramic disc of the electrostatic chuck obtained in advance; for example, the shape of all the ceramic green bodies can be circular, and the diameters of the ceramic green bodies can be the same; and the materials of all the ceramic green bodies can be the same. In the embodiment of the present application, 10 layers of ceramic green bodies can be stacked, and an electrode can be arranged on the second layer of ceramic green body or the third layer of ceramic green body in the direction from the top end to the bottom end; the electrode pattern can be prepared on the surface of the second layer of ceramic green body or the surface of the third layer of ceramic green body by printing, and the specific method includes the following steps: customizing a silk screen with an electrode pattern, fixing the screen frame on a printing machine, aligning the Mark hole drilled by laser on the ceramic green body, pouring tungsten paste on the silk screen, setting the printing parameters of the equipment, taking out the green body with the electrode pattern after printing, measuring the size by an image measuring instrument to determine whether the size is qualified, and placing the green body in an oven for drying for 10-20 minutes.

[0014] In the embodiment of the present application, each ceramic green body can be cut separately; 2-4 positioning holes can be arranged on each ceramic green body, or 3 positioning holes can be arranged, such as 3 positioning holes arranged in a triangular distribution for alignment; the positioning holes on each ceramic green body can be arranged at the same position, and the plurality of ceramic green bodies can be stacked together, and the plurality of ceramic green bodies can be fixed by the positioning holes on each ceramic green body by using positioning pins, one positioning pin can pass through the positioning holes at the corresponding positions of each ceramic green body to pass the plurality of ceramic green bodies together; the length of the positioning pin is greater than or equal to the total thickness of the plurality of ceramic green bodies stacked together; the number of positioning pins used can be determined according to the number of positioning holes; the diameters of each positioning hole can be the same or different; the diameters of each positioning pin can be the same or different. In the embodiment of the present application, the diameters of the plurality of positioning holes are the same, and the diameters of the plurality of positioning pins are the same. In the embodiment of the present application, the diameter of the positioning hole can be selected from 1-2 mm, such as 1.5 mm.

[0015] In the embodiment of the present application, the single thickness of the ceramic green body is 0.45 mm, the total number of layers is 10, the total thickness is 4.5 mm, and the diameter of the ceramic green body is 300 mm; during the stacking process, from the bottom end to the top end direction, the laser cutting circle is performed during the preparation process of the 1-8 layer ceramic green body, and three positioning holes are punched out at the same time, and the second layer is printed with an electrode pattern; the laser cutting circle is performed during the preparation process of the 9-10 layer ceramic green body, and three positioning holes and two electrode holes are punched out.

[0016] In the embodiment of the present application, after the plurality of ceramic green bodies are fixed together by the positioning pins, glue is brushed on the outer circle of the lower surface of each ceramic green body (the ceramic green body is relatively soft, and can be lifted to brush the glue), and then the plurality of ceramic green bodies are bonded together; the outer extension of the outer circle coincides with the outer extension of the ceramic body; the width of the outer circle can be selected from 5-10 mm, such as 6 mm, 7 mm, 8 mm, 9 mm; the brushed glue includes ethyl cellulose and terpineol; the mass content of the ethyl cellulose in the glue can be selected from 70-80%, such as 75%; the mass content of the terpineol in the glue can be selected from 20-30%, such as 25%. In the embodiment of the present application, the thickness of the brushed glue can be selected from 0.005-0.012 mm, such as 0.008 mm, 0.01 mm.

[0017] In the embodiment of the present application, the composition of the wax liquid is selected from paraffin wax, such as industrial paraffin wax (chemical composition straight-chain alkane); the injected wax liquid can fill the cavity formed after the positioning pin is pulled out.

[0018] In the embodiment of the present application, before isostatic pressing, it can also include:

[0019] The obtained laminated structure is loaded into a plastic packaging bag and vacuumized.

[0020] In the embodiment of the present application, the material of the plastic sealing bag can be selected from PVC heat shrinkable film; the thickness of the plastic sealing bag can be selected from 0.3-0.6 mm, such as 0.4 mm, 0.5 mm; the time for vacuumizing can be selected from 20-40 s, such as 25 s, 30 s, 35 s; the vacuum degree for vacuumizing can be selected from-0.01 MPa; after vacuumizing, the plastic sealing bag can be sealed by using the method of heat sealing; the time for heat sealing can be selected from 2-3 s, such as 2.6 s; the temperature for heat sealing can be selected from 70-90 DEG C, such as 75 DEG C, 80 DEG C, 85 DEG C.

[0021] In the embodiment of the present application, the isostatic pressing can be carried out in a warm isostatic pressing machine; the temperature (water temperature) during the isostatic pressing process can be selected from 50-70 DEG C, such as 55 DEG C, 60 DEG C, 65 DEG C; the pressure maintaining time can be selected from 70-90 s, such as 75 s, 80 s, 85 s; the preheating time can be selected from 550-650 s, such as 580 s, 600 s, 620 s; the pressure can be selected from 70-90 MPa, such as 75 MPa, 80 MPa, 85 MPa.

[0022] In the embodiment of the present application, when the ceramic green compact is made, each piece of the compact body is cut separately, and three positioning holes for alignment are left at the middle part; according to the number of the designed layers, the ceramic disc compact bodies are stacked one by one by fixing through three positioning pins; the stacked green compact is fixed by separately brushing glue on the outer circle; finally, the positioning pins are taken out, liquid wax is dripped into the positioning holes, and after the liquid wax is solidified, it plays a role of fixing and protecting the hole position. Figure 1 and Figure 2 As shown.

[0023] In the embodiment of the present application, the new method for stacking the ceramic disc green compact can comprise:

[0024] A small hole with a diameter of about 1.5 mm is punched at the fixed position of each ceramic compact body, and the shape circle is cut out; during the stacking, the positioning pins with the same diameter are inserted into the three positioning holes, and then the remaining compact bodies are stacked one by one by fixing through the positioning pins; after the stacking, a layer of glue is brushed on the outer circle of each compact body, the positioning pins are taken out after the glue is solidified, and at the same time, the wax liquid is sealed in the positioning holes, and after the wax liquid is completely solidified, the stacked compact body is placed on the glass and loaded into the plastic sealing bag for isostatic pressing.

[0025] In the prior art, the displacement of the green compact during the stacking and the glass breakage during the isostatic pressing process can cause the sealing bag to leak, and the method provided by the present application can ensure that the stacked green compact will not be displaced, greatly reducing the problems of glass breakage during the isostatic pressing and the leakage of the plastic sealing bag; the method can greatly improve the yield of the ceramic green compact, and reduce the labor cost and time cost. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The figure is a schematic diagram of the stacking process in the embodiment of the present application.

[0027] Figure 2 The figure is a schematic diagram of the glue brushing process in the embodiment of the present application. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0029] Embodiment 1

[0030] Ceramic green bodies made of alumina were used, each ceramic green body had a thickness of 0.45 mm and a diameter of 300 mm, 5 ceramic green bodies were stacked together, and the total thickness after stacking was 2.25 mm; each ceramic green body had three positioning holes arranged in a triangular shape at the same position, each positioning hole had a diameter of 1.5 mm, and the 5 ceramic green bodies were stacked together by positioning pins passing through the positioning holes.

[0031] The outer circle of the lower surface of the stacked ceramic green bodies was brushed with glue, the glue including 75 wt% of ethyl cellulose and 25 wt% of terpineol; the edge of the outer circle coincided with the outer edge of the ceramic green body, the width of the outer circle was 6 mm, and the thickness of the brushed glue was 0.005 mm; the 5 ceramic green bodies were bonded together.

[0032] The positioning pins in the bonded ceramic green bodies were pulled out, the cavities formed by the positioning pins were filled with paraffin liquid, and after the paraffin solidified, the ceramic green bodies were stacked and fixed together; then they were put into a plastic sealing bag for vacuumizing, the vacuum degree was-0.01 MPa, vacuumizing was performed for 30 s, then the plastic sealing bag was sealed by heating and plasticizing, the heating and plasticizing time was 2.6 s, and the temperature was 80℃.

[0033] The stacked structure after plasticizing was subjected to isostatic pressing, the water temperature for isostatic pressing was 60℃, the pressure maintaining time was 80 s, the preheating time was 600 s, and the pressure was 80 MPa.

[0034] The stacked structure after isostatic pressing in the test embodiment 1 was tested, which was not water leakage, the diameter size (tested by a vernier caliper) was 300.5 mm, the density (tested according to GB / T 611-2021) was 2.8 kg / m 3 , and the total thickness (tested by a vernier caliper) was 2.18 mm.

[0035] Embodiment 2

[0036] The stacked structure was prepared according to the method of embodiment 1, and the difference from embodiment 1 was that the pressure for isostatic pressing was 40 MPa.

[0037] The isostatic pressed laminated structure of Example 2 was tested and no water leakage was found, the diameter size was 300.4mm, the density was 2.6kg / m 3 ; and the total thickness was 2.21mm.

[0038] Example 3

[0039] The laminated structure was prepared according to the method of Example 1, and the difference from Example 1 was that the width of the outer ring was 2mm.

[0040] The isostatic pressed laminated structure of Example 3 was tested and no water leakage was found, the diameter size (size deviation) was 300.6mm, the density was 2.8kg / m 3 ; and the total thickness was 2.18mm.

[0041] Comparative Example 1

[0042] The laminated structure was prepared according to the method of Example 1, and the difference from Example 1 was that the positioning pins were not pulled out after being positioned, and wax sealing was not performed.

[0043] The isostatic pressed laminated structure of Comparative Example 1 was tested and water leakage and cracking were found, the diameter size was 300.5mm, the density was 2.8kg / m 3 ; and the total thickness was 2.18mm.

[0044] In the prior art, there are three positioning pins on the platform, and the ceramic green body is stacked in order from 1 to 10 layers. After the stacking is completed, the positioning pins are not removed (to serve as a fixing function). The semi-finished product is placed on a glass plate, and is placed in a plastic sealing bag to be vacuumized. Finally, the entire product is isostatic pressed. Since the positioning pins are hard, they can easily break through the glass plate and the plastic sealing bag under the pressure of tens of megapascals in the isostatic pressing equipment, resulting in water leakage and product scrap. If the isostatic pressing pressure is not increased, the product will not be dense enough. In the present application, the positioning pins are used for stacking, and glue is brushed around each ceramic green body. After the stacking is completed, the positioning pins are removed, and wax is dripped into the positioning holes of the ceramic green body to serve as a fixing function. Similarly, the semi-finished product is placed on a glass plate, and is placed in a plastic sealing bag to be vacuumized. Finally, the entire product is isostatic pressed. In the present application, the product will not leak after the positioning pins are removed and the wax is sealed. If the width of the glue brushing is within the range of 5-10mm, the product will not be deviated after isostatic pressing.

[0045] The present application provides a new laminating method for ceramic disc green bodies, which is characterized in that glue is brushed around each layer of green body after the ceramic body is stacked, and the positioning pins are removed and sealed with wax. The method provided by the present application can ensure that the stacked green bodies will not be displaced, greatly reducing the problems of glass breakage and plastic sealing bag water leakage during isostatic pressing. Through the method provided by the present application, the work efficiency is improved, and the labor cost is also reduced.

[0046] While the application has been described and illustrated with reference to specific embodiments thereof, those skilled in the art will appreciate that various adaptations, changes, modifications, substitutions, developments, improvements, and permutations can be made in the specific embodiments described without departing from the true spirit and scope of the application as defined by the appended claims. All such modifications are intended to be within the scope of the claims. Although methods disclosed herein have been described with reference to particular operations performed in a particular order, it will be understood that these operations can be combined, sub-divided, or re-ordered to form equivalent methods without departing from the teachings of the present application. Accordingly, unless specifically indicated herein, the order and grouping of operations are not a limitation of this application.

Claims

1. A new method for stacking green bodies of ceramic discs, comprising: stacking a plurality of green bodies of ceramic together by positioning pins; removing the positioning pins from the stacked green bodies of ceramic, injecting a wax liquid into the cavities formed by the positioning holes, and obtaining a stacked structure after the wax liquid solidifies; isostatic pressing the stacked structure.

2. The method of claim 1, wherein, The green bodies of ceramic are circular in shape.

3. The method of claim 1, wherein, The diameter of the green bodies of ceramic is selected from 280-320 mm; and the thickness of the green bodies of ceramic is selected from 0.4-0.5 mm.

4. The method of claim 1, wherein, The plurality of green bodies of ceramic is 5-12 green bodies of ceramic.

5. The method of claim 1, wherein, 2-4 positioning holes are provided on each green body of ceramic.

6. The method of claim 1, wherein, After the plurality of green bodies of ceramic are stacked together by the positioning pins, the method further comprises: applying glue to the outer circle of the surface of each green body of ceramic to bond the plurality of green bodies of ceramic together.

7. The method of claim 1, wherein, The wax liquid comprises paraffin wax.

8. The method of claim 1, wherein, The thickness of the stacked structure is selected from 4-5 mm.

9. The method of claim 6, wherein, The thickness of the applied glue is selected from 0.005-0.012 mm.

10. The method of claim 1, wherein, The pressure in the isostatic pressing process is selected from 70-90 MPa.

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