Processing method for solving heat dissipation of contact surface of wafer and electrostatic chuck

Abstract

The invention relates to a processing method for solving heat dissipation of a contact surface of a wafer and an electrostatic chuck, which belongs to the technical field of silicon wafer processing, and comprises the following operation steps of: 1, grinding a silicon wafer; and 2, cleaning the surface of the silicon wafer through NAOH, SC1 and pure water. And 3, carrying out acid corrosion on the silicon wafer in a mixed solution of HF, HNO3 and H3PO4, wherein the corrosion rate needs to be regulated and controlled to 0.8-1 [mu] m / s so as to ensure the glossiness and roughness of the back surface. And 4, corroding the silicon wafer through PC-DH2 / TMAH, HF and pure water, and then cleaning the silicon wafer. And 5, carrying out BSD sand blasting treatment on the back surface of the silicon wafer by using a grinding liquid formed by mixing a 3000 # silicon dioxide grinding material and pure water. And 6, cleaning the silicon wafer subjected to the sand blasting treatment by adopting SC1. The problem of adapting to the temperature of the electrostatic chuck is solved. H3P04 is used for acid corrosion, and the glossiness of the back surface of the silicon wafer is ensured in a state of a relatively high corrosion rate. And meanwhile, large-particle salient points on the back surface caused by acid corrosion are filled in a BSD sand blasting manner.

Description

Technical Field

[0001] The invention relates to the technical field of silicon wafer processing, and in particular to a processing method for solving the heat dissipation problem of a contact surface between a wafer and an electrostatic chuck. Background Art

[0002] Electrostatic adsorption technology is widely used in the fields of semiconductors, optics, etc. Electrostatic chuck (E-CHUCK) is an ultra-clean wafer carrier suitable for vacuum and plasma working environments. It uses the principle of electrostatic adsorption to clamp ultra-thin wafers evenly and is a core component of high-end equipment such as PVD, ETCH, and ion implantation.

[0003] The back temperature measurement is the comprehensive result of the emissivity of the back of the wafer and the actual physical temperature of the wafer. This has led to some large chip manufacturers having certain special requirements for the back state of the silicon wafer due to equipment and process issues in order to meet the processing and production of chips. However, the actual problem is that the "large particle" bumps on the back of the silicon wafer will cause poor contact in the attached area, resulting in poor actual heat dissipation efficiency in the area. Summary of the invention

[0004] The present invention mainly solves the deficiencies in the prior art, provides a processing method for heat dissipation of the contact surface between the wafer and the electrostatic chuck, and solves the problem of adapting the temperature of the electrostatic chuck. H3PO4 is used through acid corrosion and the glossiness of the back of the silicon wafer is ensured at a higher corrosion rate. At the same time, the large particle bumps on the back caused by acid corrosion are filled by BSD sandblasting.

[0005] The above technical problems of the present invention are mainly solved by the following technical solutions:

[0006] A processing method for solving the heat dissipation of the contact surface between a wafer and an electrostatic chuck includes the following steps:

[0007] Step 1: Use 1200# grinding powder to grind the silicon wafer. 1200# grinding powder is also called 1200 mesh grinding powder.

[0008] Step 2: Clean the surface of the silicon wafer with NAOH, SC1 and pure water to remove surface impurities and oxide layers.

[0009] Step 3: The silicon wafer is acid-etched in a mixed solution of HF, HNO3, and H3PO4. The etching rate needs to be controlled to 0.8-1 μm / s to ensure the glossiness and roughness of the back side.

[0010] Step 4: Etch and clean the silicon wafer using PC-DH2 / TMAH, HF and pure water.

[0011] TMAH is mainly composed of tetramethylammonium hydroxide, which contains carbon, hydrogen, nitrogen and oxygen elements. It is an organic base with high stability and good solubility. TMAH is alkaline and can react with acids to neutralize. TMAH is a colorless, transparent liquid with low melting and boiling points. It has high solubility in water and is easy to dilute. In addition, TMAH also has low volatility and high stability.

[0012] Step 5: Use a mixture of 3000# silica abrasive and pure water to perform BSD sandblasting on the back of the silicon wafer. 3000# silica abrasive is also called 3000 mesh silica abrasive.

[0013] Step 6: Use SC1 to clean the silicon wafer after sandblasting.

[0014] Preferably, when 1200# grinding powder is used to grind silicon wafers, the grinding liquid is discharged in a straight line manner, and the carrier rotation speed is 9 to 19 rpm.

[0015] Preferably, the mixed solution of HF, HNO3, and H3PO4 has a ratio of HF: 12-14wt%, HNO3: 34-36wt%, H3PO4: 13-16wt%, and the rest is pure water.

[0016] Preferably, the acid etching processing temperature is 20-30° C., the bubbling pressure is 0.02-0.05 MPa, and the silicon wafer rotation speed is 20-30 rpm.

[0017] Preferably, the acid etching removal amount is 25 to 35 μm.

[0018] Preferably, the density of the silica abrasive liquid used in BSD sandblasting is 1.005-1.025 g / cm 3 .

[0019] Preferably, the pressure of BSD sandblasting is 0.025-0.080 MPa.

[0020] The present invention can achieve the following effects:

[0021] The present invention provides a processing method for solving the heat dissipation of the contact surface between the wafer and the electrostatic chuck. Compared with the prior art, the problem of adapting the temperature of the electrostatic chuck is solved. H3PO4 is used through acid corrosion and the glossiness of the back of the silicon wafer is ensured at a higher corrosion rate. At the same time, the large particle bumps on the back caused by acid corrosion are filled by BSD sandblasting. DETAILED DESCRIPTION

[0022] The technical solution of the invention is further specifically described below through embodiments.

[0023] Embodiment: A processing method for solving the heat dissipation of the contact surface between a wafer and an electrostatic chuck comprises the following steps:

[0024] Step 1: Use 1200# grinding powder to grind the silicon wafer. The grinding liquid is discharged in a straight line, and the carrier rotation speed is 14rpm.

[0025] Step 2: Clean the silicon wafer surface with NAOH, SC1 and pure water.

[0026] Step 3: The silicon wafer is acid-etched in a mixed solution of HF, HNO3, and H3PO4. The etching rate needs to be adjusted to 0.8-1μm / s to ensure the gloss and roughness of the back surface. The mixed solution ratio is HF: 13wt%, HNO3: 35wt%, H3PO4: 15wt%, and the rest is pure water. The acid etching processing temperature is 25℃, the bubbling pressure is 0.02-0.05Mpa, and the silicon wafer rotation speed is 26rpm. The acid etching removal amount is 27μm.

[0027] Step 4: Etch and clean the silicon wafer using PC-DH2 / TMAH, HF and pure water.

[0028] Step 5: Use 3000# silica abrasive mixed with pure water to perform BSD sandblasting on the back of the silicon wafer. The density of silica abrasive used in BSD sandblasting is 1.005-1.025g / cm 3 The pressure of BSD sandblasting is 0.025~0.080Mpa.

[0029] Step 6: Use SC1 to clean the silicon wafer after sandblasting.

[0030] In summary, the processing method for heat dissipation of the contact surface between the wafer and the electrostatic chuck solves the problem of adapting the temperature of the electrostatic chuck. H3PO4 is used through acid etching and the glossiness of the back of the silicon wafer is ensured at a higher etching rate. At the same time, BSD sandblasting is used to fill the large particle bumps on the back caused by acid etching.

[0031] The above description is only a specific embodiment of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by any technician in the field of the present invention are included in the patent scope of the present invention.

Claims

1. A method for heat dissipation between a wafer and an electrostatic chuck contact surface, characterized in that The steps are as follows: Step 1: Grind the silicon wafer using 1200# grinding powder; Step 2: Clean the surface of the silicon wafer with NAOH, SC1 and pure water; Step 3: The silicon wafer is acid-etched in a mixed solution of HF, HNO3, and H3PO4. The etching rate needs to be controlled to 0.8-1 μm / s to ensure the glossiness and roughness of the back side. Step 4: Clean the silicon wafer after etching using PC-DH2 / TMAH, HF and pure water; Step 5: Use a 3000# silica abrasive mixed with pure water to perform BSD sandblasting on the back of the silicon wafer; Step 6: Use SC1 to clean the silicon wafer after sandblasting.

2. The method for processing heat dissipation at the contact surface between a wafer and an electrostatic chuck according to claim 1, characterized in that: When 1200# grinding powder is used to grind silicon wafers, the grinding liquid is discharged in a straight line and the carrier rotation speed is 9 to 19 rpm.

3. The method for heat dissipation between the contact surface of the wafer and the electrostatic chuck according to claim 1, characterized in that: The proportions of the mixed solution of HF, HN03, and H3PO4 are HF: 12-14wt%, HNO3: 34-36wt%, H3PO4: 13-16wt%, and the rest is pure water.

4. The method for processing heat dissipation at the contact surface between the wafer and the electrostatic chuck according to claim 3, characterized in that: The acid etching processing temperature is 20-30°C, the bubbling pressure is 0.02-0.05Mpa, and the silicon wafer rotation speed is 20-30rpm.

5. The method for processing heat dissipation at the contact surface between a wafer and an electrostatic chuck according to claim 3 or 4, characterized in that: The acid etching removal amount is 25 to 35 μm.

6. The method for heat dissipation between the contact surface of the wafer and the electrostatic chuck according to claim 1, characterized in that: The density of silica abrasive slurry used in BSD sandblasting is 1.005-1.025 g / cm 3 .

7. The method for processing heat dissipation at the contact surface between a wafer and an electrostatic chuck according to claim 6, characterized in that: The pressure of BSD sandblasting is 0.025~0.080Mpa.