A method for preparing a silicon wafer vacuum chuck with a multi-element composite ceramic coating

Abstract

The application provides a preparation method of a silicon wafer vacuum chuck with a multi-element composite ceramic coating. The silicon wafer vacuum chuck with the multi-element composite ceramic coating comprises, from bottom to top, a vacuum chuck blank, a nickel-aluminum bonding layer and a chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating. The preparation method comprises the following steps: S1. mixing aluminum powder, SiC powder with a metal plating layer on the surface and paraffin to obtain a mixture; S2. pressing the mixture into a vacuum chuck blank; S3. sintering; S4. primary annealing; S5. sequentially spraying the nickel-aluminum bonding layer and the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating on the vacuum chuck blank by plasma spraying to obtain a vacuum chuck semi-finished product; and S6. secondary annealing, grinding and polishing to obtain the silicon wafer vacuum chuck with the multi-element composite ceramic coating. The application obtains the vacuum chuck with light quality, high strength and rigidity and a wear-resistant surface, so as to effectively overcome the defects of the original alloy silicon wafer vacuum chuck, such as large weight and poor wear resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of filling materials, and in particular to a method for preparing a silicon wafer vacuum suction cup with a multi-component composite ceramic coating. Background Art

[0002] Silicon wafers are widely used in the photovoltaic and new energy industries. After being cut, silicon wafers must undergo various grinding and polishing processes. During this process, the silicon wafers are grasped using vacuum suction cups. The following requirements are imposed on the vacuum chuck for silicon wafers: (1) High lightweight: To reduce the inertia of motion, reduce the load on the motor, and improve motion efficiency, positioning accuracy, and stability, lightweight structural design is generally adopted for structural parts, with a lightweight rate of 60% to 80%, and up to 90%; (2) High form and position accuracy: To achieve high-precision motion and positioning, structural parts are required to have extremely high form and position accuracy, with flatness, parallelism, and perpendicularity required to be less than 1 μm, and form and position accuracy required to be less than 5 μm; (3) High dimensional stability: To achieve high-precision motion and positioning, structural parts are required to have extremely high dimensional stability, not prone to strain, with a small expansion coefficient, and high thermal conductivity, and not prone to large dimensional deformation; (4) The working surface of the chuck needs to have high hardness: Due to the high hardness of the silicon wafer, repeated contact with the chuck and the high-hardness silicon particles adhering to the working surface of the chuck will cause certain wear on the working surface of the chuck. Therefore, the working surface of the traditional alloy chuck is often worn after a period of use, resulting in surface roughening and decreased adsorption force of the chuck. Summary of the Invention

[0003] The purpose of the present invention is to overcome and supplement the deficiencies in the prior art and provide a method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating. The blank of the silicon wafer vacuum chuck is prepared by an aluminum alloy ceramic powder metallurgy process. Then, an alloy bonding layer and a high-hardness multi-component composite ceramic coating are sprayed on the working surface of the chuck in sequence using plasma, thereby preparing a new silicon wafer vacuum chuck with light weight, small expansion coefficient, and wear-resistant working surface.

[0004] The technical solution adopted in the present invention is:

[0005] A method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating, wherein: the silicon wafer vacuum chuck with the multi-component composite ceramic coating comprises, from bottom to top, a vacuum chuck blank, a nickel-aluminum bonding layer, and a chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating;

[0006] The preparation method comprises the following steps:

[0007] Step S1. mixing aluminum powder, SiC powder with a metal coating on the surface, and paraffin to obtain a mixture;

[0008] Step S2. The mixture is pressed into a vacuum chuck body by pressing, and then dried;

[0009] Step S3: Sintering and densifying the dried vacuum chuck green body;

[0010] Step S4. annealing the sintered vacuum chuck blank, and then sandblasting and cleaning the vacuum chuck blank;

[0011] Step S5. A nickel-aluminum bonding layer having a thickness of 50 to 150 microns and a chromium oxide - aluminum oxide - lanthanum oxide composite ceramic coating having a thickness of 100 to 500 microns are sequentially sprayed on the vacuum chuck blank by plasma spraying to obtain a semi-finished vacuum chuck;

[0012] Step S6: The vacuum chuck semi-finished product of step S5 is subjected to secondary annealing, and then the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating is ground and polished using a surface grinder and a grinding device in sequence to obtain a silicon wafer vacuum chuck with a multi-component composite ceramic coating.

[0013] Preferably, the method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating is characterized in that the mass ratio of the aluminum powder, the SiC powder with a metal coating on the surface, and the paraffin in step S1 is 23-35:63-75:2-5.

[0014] Preferably, in the method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating, the metal coating on the surface of the SiC powder with a metal coating is made of Ni or Cu, and the average thickness of the coating is 0.01 to 10 µm.

[0015] Preferably, in the method for preparing the silicon wafer vacuum chuck with a multi-component composite ceramic coating, the pressure of pressing the mixture in step S2 is 50-300 MPa, the drying temperature is 40-60° C., and the drying time is 12-24 hours.

[0016] Preferably, the method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating, wherein: the sintering and densification process in step S3 is specifically: placing the vacuum chuck blank in a vacuum furnace and heating it to 350°C and keeping it warm for 1 hour, then heating it to 500°C and keeping it warm for 1 hour, and finally heating it to 560-620°C and keeping it warm for 1.5 hours.

[0017] Preferably, in the method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating, the temperature of the primary annealing in step S4 is 160-190° C., and the holding time of the primary annealing is 6-12 hours.

[0018] Preferably, the method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating is described, wherein: in step S5, the nickel-aluminum bonding layer comprises 10-30% aluminum and 70-90% nickel, calculated by mass percentage; and the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating comprises 75%-85% chromium oxide, 13%-20% aluminum oxide and 2-5% lanthanum oxide.

[0019] Preferably, the method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating, wherein: the plasma spraying parameters in step S5 are: voltage of 40-60V, current of 450-650A, argon flow rate of 30-60L / min, hydrogen flow rate of 5-15L / min, powder feeding rate of 30-60g / min, and spraying distance of 60-100mm.

[0020] Preferably, in the method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating, the temperature of the secondary annealing in step S6 is 160-190° C., and the holding time of the secondary annealing is 6-12 hours.

[0021] Preferably, in the method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating, the surface roughness of the silicon wafer vacuum chuck with the multi-component composite ceramic coating in step S6 is Ra 0.1-0.2.

[0022] Advantages of the present invention:

[0023] The present invention discloses a method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating. First, a powder metallurgy process is used to prepare a blank of an Al-SiC molded silicon wafer vacuum chuck. Then, an alloy bonding layer and a ceramic working layer are sequentially sprayed on the working surface of the chuck by plasma spraying. Then, grinding, polishing and stress relief annealing are combined to stabilize the dimensions. Thus, a vacuum chuck with light weight, high strength and rigidity, and a wear-resistant surface is obtained, thereby effectively overcoming the defects of the original alloy silicon wafer vacuum chuck, such as heavy weight and poor wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a silicon wafer vacuum chuck with a multi-component composite ceramic coating according to the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0026] The manufacturer of SiC powder with Cu or Ni coating on the surface is Yichang Huabang Graphite Co., Ltd.

[0027] Example 1

[0028] like Figure 1A method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating, wherein the silicon wafer vacuum chuck with the multi-component composite ceramic coating comprises, from bottom to top, a vacuum chuck blank 1, a nickel-aluminum bonding layer 2, and a chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating 3;

[0029] Wherein: the preparation method comprises the following steps:

[0030] Step S1. A mixture is prepared by mixing aluminum powder, SiC powder with a metal coating, and paraffin wax; the mass ratio of the aluminum powder, the SiC powder with a metal coating, and the paraffin wax is 30%:67%:3%, the metal coating of the SiC powder with a metal coating is made of Ni, and the average thickness of the coating is 100 nm;

[0031] Step S2. The mixture is pressed into a vacuum chuck body 1 at a pressure of 100 MPa, and then dried at a temperature of 50°C for 20 hours.

[0032] Step S3. Sintering the dried vacuum chuck body to densify it. The sintering densification process is as follows: heating the vacuum chuck body in a vacuum furnace to 350°C for 1 hour, then to 500°C for 1 hour, and finally to 585°C for 1.5 hours.

[0033] Step S4. The sintered vacuum chuck blank is subjected to a primary annealing process at a temperature of 180°C for a holding time of 10 hours, followed by sandblasting, roughening, and cleaning of the vacuum chuck blank.

[0034] Step S5. A 100-μm-thick nickel-aluminum bonding layer 2 and a 300-μm-thick chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating 3 are sequentially sprayed on the vacuum chuck blank by plasma spraying. In step S5, the nickel-aluminum bonding layer comprises 20% aluminum and 80% nickel by mass percentage; the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating comprises 80% chromium oxide, 17% aluminum oxide, and 3% lanthanum oxide. The plasma spraying parameters for the nickel-aluminum bonding layer are: voltage 55 V, current 500 A, argon flow rate 40 L / min, hydrogen flow rate 5 L / min, powder feed rate 45 g / min, and spraying distance 95 mm; the plasma spraying parameters for the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating are: voltage 55 V, current 550 A, argon flow rate 45 L / min, hydrogen flow rate 8 L / min, powder feed rate 35 g / min, and spraying distance 75 mm, to obtain a semi-finished vacuum chuck;

[0035] Step S6: The vacuum chuck semi-finished product of step S5 is subjected to secondary annealing at a temperature of 185°C and a holding time of 10 hours. Subsequently, the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating is ground and polished using a surface grinder and a grinding device in sequence to obtain a silicon wafer vacuum chuck with a surface roughness of Ra0.12 and a multi-component composite ceramic coating.

[0036] The thermal expansion coefficient of the silicon wafer vacuum chuck with the multi-component composite ceramic coating prepared in Example 1 is 7 × 10 -6 / ℃, and its abrasion resistance is more than 20 times higher than that of ordinary cast iron.

[0037] Example 2

[0038] like Figure 1 A method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating, wherein the silicon wafer vacuum chuck with the multi-component composite ceramic coating comprises, from bottom to top, a vacuum chuck blank 1, a nickel-aluminum bonding layer 2, and a chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating 3;

[0039] Wherein: the preparation method comprises the following steps:

[0040] Step S1. A mixture is prepared by mixing aluminum powder, SiC powder with a metal coating, and paraffin wax; the mass ratio of the aluminum powder, the SiC powder with a metal coating, and the paraffin wax is 20%:75%:5%, the metal coating of the SiC powder with a metal coating is made of Ni, and the average thickness of the coating is 200 nm;

[0041] Step S2. The mixture is pressed into a vacuum chuck body at a pressure of 120 MPa, and then dried at a temperature of 50°C for 20 hours.

[0042] Step S3. Sintering the dried vacuum chuck body to densify it. The sintering densification process is as follows: heating the vacuum chuck body in a vacuum furnace to 350°C for 1 hour, then to 500°C for 1 hour, and finally to 580°C for 1.5 hours.

[0043] Step S4. The sintered vacuum chuck body is subjected to a primary annealing process at a temperature of 185°C for a holding time of 8 hours, followed by sandblasting, roughening, and cleaning of the vacuum chuck body.

[0044] Step S5. A 100-μm-thick nickel-aluminum bonding layer and a 300-μm-thick chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating were sequentially sprayed onto the vacuum chuck body using plasma spraying. In step S5, the nickel-aluminum bonding layer comprised 25% aluminum and 75% nickel, and the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating comprised 84% chromium oxide, 13% aluminum oxide, and 3% lanthanum oxide. The plasma spraying parameters were: voltage 55 V, current 550 A, argon flow rate 45 L / min, hydrogen flow rate 8 L / min, powder feed rate 35 g / min, and spraying distance 75 mm.

[0045] Step S6: The vacuum chuck semi-finished product of step S5 is subjected to secondary annealing at a temperature of 190°C and a holding time of 8 hours. Subsequently, the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating is ground and polished using a surface grinder and a grinding device in sequence to obtain a silicon wafer vacuum chuck with a surface roughness of Ra0.12 and a multi-component composite ceramic coating.

[0046] The thermal expansion coefficient of the silicon wafer vacuum chuck with the multi-component composite ceramic coating prepared in Example 2 is 6.8 × 10 -6 / ℃, and its abrasion resistance is more than 20 times higher than that of ordinary cast iron.

[0047] Example 3

[0048] like Figure 1 A method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating, wherein the silicon wafer vacuum chuck with the multi-component composite ceramic coating comprises, from bottom to top, a vacuum chuck blank 1, a nickel-aluminum bonding layer 2, and a chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating 3;

[0049] Wherein: the preparation method comprises the following steps:

[0050] Step S1. A mixture is prepared by mixing aluminum powder, SiC powder with a metal coating, and paraffin wax; the mass ratio of the aluminum powder, the SiC powder with a metal coating, and the paraffin wax is 25%:73%:2%, the metal coating of the SiC powder with a metal coating is made of Ni or Cu, and the average thickness of the coating is 2µm;

[0051] Step S2. The mixture is pressed into a vacuum chuck body at a pressure of 200 MPa, and then dried at a temperature of 50°C for 20 hours.

[0052] Step S3. Sintering the dried vacuum chuck body to densify it. The sintering densification process is as follows: heating the vacuum chuck body in a vacuum furnace to 350°C for 1 hour, then to 500°C for 1 hour, and finally to 620°C for 1.5 hours.

[0053] Step S4. The sintered vacuum chuck body is subjected to a primary annealing process at a temperature of 190°C for a holding time of 6 hours, followed by sandblasting, roughening, and cleaning of the vacuum chuck body.

[0054] Step S5. A 100-μm-thick nickel-aluminum bonding layer and a 300-μm-thick chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating were sequentially sprayed onto the vacuum chuck blank by plasma spraying. In step S5, the nickel-aluminum bonding layer comprised 28% aluminum and 82% nickel; the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating comprised 78% chromium oxide, 18% aluminum oxide, and 4% lanthanum oxide. The plasma spraying parameters were: voltage 50 V, current 550 A, argon flow rate 45 L / min, hydrogen flow rate 8 L / min, powder feed rate 35 g / min, and spraying distance 75 mm, yielding a semi-finished vacuum chuck.

[0055] Step S6: The vacuum chuck semi-finished product of step S5 is subjected to secondary annealing at a temperature of 190°C and a holding time of 8 hours. Subsequently, the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating is ground and polished using a surface grinder and a grinding device in sequence to obtain a silicon wafer vacuum chuck with a surface roughness of Ra0.1 and a multi-component composite ceramic coating.

[0056] The thermal expansion coefficient of the silicon wafer vacuum chuck with the multi-component composite ceramic coating prepared in Example 3 is 6.9 × 10 -6 / ℃, and its abrasion resistance is more than 20 times higher than that of ordinary cast iron.

[0057] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating, characterized by: The silicon wafer vacuum chuck with a multi-component composite ceramic coating comprises, from bottom to top, a vacuum chuck blank (1), a nickel-aluminum bonding layer (2), and a chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating (3); The preparation method comprises the following steps: Step S1. mixing aluminum powder, SiC powder with a metal coating on the surface, and paraffin to obtain a mixture; Step S2. Pressing the mixture into a vacuum suction cup blank (1) by pressing, and then drying; Step S3: Sintering and densifying the dried vacuum chuck green body; Step S4. annealing the sintered vacuum chuck blank, and then sandblasting and cleaning the vacuum chuck blank; Step S5. Using plasma spraying, a nickel-aluminum bonding layer (2) with a thickness of 50 to 150 microns and a chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating (3) with a thickness of 100 to 500 microns are sequentially sprayed on the vacuum chuck blank to obtain a semi-finished vacuum chuck; Step S6: performing secondary annealing on the semi-finished vacuum chuck of step S5, and then grinding and polishing the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating using a surface grinder and a grinding device in sequence to obtain a silicon wafer vacuum chuck with a multi-component composite ceramic coating; In step S1 , the mass ratio of the aluminum powder, the SiC powder with a metal coating on the surface, and the paraffin wax is 23-35:63-75:2-5, and the material of the metal coating in the SiC powder with a metal coating on the surface is Ni or Cu.

2. The method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating according to claim 1, characterized in that: The average thickness of the coating is 0.01 to 10 μm.

3. The method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating according to claim 1, characterized in that: In step S2, the pressure of pressing the mixed material is 50-300 MPa, the temperature of drying is 40-60° C., and the drying time is 12-24 hours.

4. The method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating according to claim 1, wherein: The sintering and densification process in step S3 is as follows: the vacuum chuck green body is placed in a vacuum furnace and heated to 350°C for 1 hour, then heated to 500°C for 1 hour, and finally heated to 560-620°C for 1.5 hours.

5. The method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating according to claim 1, wherein: The temperature of the primary annealing in step S4 is 160-190° C., and the holding time of the primary annealing is 6-12 hours.

6. The method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating according to claim 1, wherein: In terms of mass percentage, the nickel-aluminum bonding layer in step S5 includes 10-30% aluminum and 70-90% nickel; the chromium oxide-aluminum oxide-lanthanum oxide composite ceramic coating includes 75-85% chromium oxide, 13-20% aluminum oxide and 2-5% lanthanum oxide.

7. The method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating according to claim 1, wherein: The plasma spraying parameters in step S5 are: voltage of 40-60V, current of 450-650A, argon flow rate of 30-60L / min, hydrogen flow rate of 5-15L / min, powder feeding rate of 30-60g / min, and spraying distance of 60-100mm.

8. The method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating according to claim 1, wherein: The temperature of the secondary annealing in step S6 is 160-190° C., and the holding time of the secondary annealing is 6-12 hours.

9. The method for preparing a silicon wafer vacuum chuck with a multi-component composite ceramic coating according to claim 1, wherein: The surface roughness of the silicon wafer vacuum chuck with the multi-component composite ceramic coating in step S6 is Ra0.1-0.2.

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