Processing technology for improving back sealing appearance of silicon wafer

Abstract

The invention relates to a processing technology for improving the back sealing appearance of a silicon wafer, which belongs to the technical field of silicon wafer processing, and comprises the following operation steps of: 1, cleaning a silicon wafer subjected to double-sided polishing before APCVD (Amplitude Plasma Chemical Vapor Deposition) processing; 2, the silicon wafer enters a machine table to be subjected to SiO2 film forming reaction, and the wafer conveying speed is 190-210 mm / min; 3, the temperatures T1 of three reaction nozzles for APCVD processing are set to be 620-700 DEG C respectively; t2 is equal to 560 to 640 DEG C; and T3 is equal to 460 to 540 DEG C. And 4, plating a layer of SiO2 thin film, namely LTO, on the back surface of the silicon wafer, wherein the thickness of the thin film is 0.3-0.6 mu m. And 5, cleaning the silicon wafer after back sealing. And 6, the silicon wafer after APCVD processing is used for subsequent polishing and cleaning processing. The method has the advantages of convenient process operation and good back sealing film forming stability. By improving technological parameters in the machining process of APCVD back sealing products, powdery stains attached to the surfaces of the machined wafers are avoided, and film forming is even and free of other appearance abnormity. And the one-time processing finished product yield of the product is improved.

Description

Technical Field

[0001] The invention relates to the technical field of silicon wafer processing, and in particular to a processing technology for improving the appearance of a silicon wafer back seal. Background Art

[0002] In the semiconductor manufacturing industry, the surface quality of silicon wafers is crucial to the performance of the final product. In the chemical vapor deposition (CVD) process, the quality of the silicon wafer surface is particularly critical to the subsequent processing flow and the performance of the final product. However, in the existing atmospheric pressure chemical vapor deposition (APCVD) technology, affected by the reaction conditions, such as the reaction gas silane (SiH4), oxygen (O2), hydrogen (H2), etc., the temperature field, the morphology of the silicon wafer itself, etc., incomplete reaction products will appear, mostly white powdery SiO2, attached to the surface of the silicon wafer. The powder caused by the above reasons will cause contamination of the silicon wafer surface, thereby affecting the subsequent polishing and cleaning processes, and causing poor appearance, and in severe cases, the product will be scrapped.

[0003] Powdered pollution attached to the surface of silicon wafers will remain on the contact position, such as trays, robotic arms, etc., after the silicon wafers come into contact with machine parts during processing, and it is difficult to clean. In the subsequent processing of products, the contaminated contact parts will cause contamination of normal silicon wafers, resulting in serious losses of processed products. Summary of the invention

[0004] The present invention mainly solves the deficiencies in the prior art and provides a processing technology for improving the appearance of silicon wafer back seals, which has the advantages of convenient process operation and good back seal film formation stability. By improving the process parameters of the APCVD back seal product processing process, powder stains attached to the surface of the wafer after processing are avoided, and the film is formed uniformly without other appearance abnormalities. The first-time processing finished product yield of the product is improved.

[0005] The above technical problems of the present invention are mainly solved by the following technical solutions: A processing technology for improving the appearance of a silicon wafer back seal comprises the following steps: The first step: clean the double-sided polished silicon wafer before APCVD processing to remove particles and metal impurities on the surface of the silicon wafer, making the subsequent SiO2 film formation more stable.

[0006] Step 2: The silicon wafer enters the machine for SiO2 film formation reaction, and the wafer transfer speed is 190-210 mm / min; Step 3: The temperatures of the three reaction nozzles for APCVD processing are set as T1=620~700℃; T2=560~640℃; T3=460~540℃ respectively.

[0007] Step 4: A layer of SiO2 film, namely LTO, is coated on the back of the silicon wafer with a thickness of 0.3 to 0.6 μm.

[0008] Step 5: After the silicon wafer is back-sealed, clean it again to remove excess impurities on the SiO2 film surface.

[0009] Step 6: The silicon wafer after APCVD processing is used for subsequent polishing and cleaning.

[0010] Preferably, the silicon wafer is cleaned before APCVD processing and again after back sealing with SC-1 solution for 5 to 15 minutes; then cleaned with HF solution at a concentration of 0.1 to 0.4% for 5 to 15 minutes; washed with pure water for 5 to 15 minutes and then dried for use.

[0011] Preferably, the gas flow ratio of the reaction gas SiH4 to O2 is in the range of 1:6 to 1:16, preferably 1:8 to 1:14, to ensure an excess of O2 and complete reaction of SiH4.

[0012] Preferably, the temperature difference between T1 and T2 is set to be ≤60° C. This prevents the edge of the wafer from warping due to excessive temperature difference at the initial stage of processing, and prevents SiO2 from being uniformly film-formed in the warped area, thereby generating powdered SiO2 attached to the area.

[0013] Preferably, the three reaction nozzles extend sequentially from the center to the edge, T1 is the processing temperature of the center of the silicon wafer, and T3 is the processing temperature of the edge of the silicon wafer.

[0014] Preferably, during the heating process, the temperature at the edge gradually increases according to a gradient of 55°C to 60°C; and the temperature at the center gradually increases according to a gradient of 60°C to 65°C.

[0015] The present invention can achieve the following effects: The present invention provides a processing technology for improving the appearance of silicon wafer back seals. Compared with the prior art, the present invention has the advantages of convenient process operation and good back seal film forming stability. By improving the process parameters of the APCVD back seal product processing process, powder stains attached to the surface of the wafer after processing are avoided, and the film is formed uniformly without other appearance abnormalities. The first-time processing finished product yield of the product is improved. DETAILED DESCRIPTION

[0016] The technical solution of the invention is further specifically described below through embodiments.

[0017] Embodiment: A processing technology for improving the appearance of a silicon wafer back seal comprises the following steps: Step 1: Clean the double-sided polished silicon wafer before APCVD processing. Use SC-1 solution to clean for 5 to 15 minutes; then use HF solution with a concentration of 0.3% for 10 minutes; wash with pure water for 11 minutes and dry for use.

[0018] Step 2: The silicon wafer enters the machine for SiO2 film formation reaction, and the wafer transfer speed is 200mm / min; the gas flow ratio range of the reaction gas SiH4 and O2 is 1:12.

[0019] Step 3: The temperatures of the three reaction nozzles for APCVD processing are set to T1=660℃, T2=600℃ and T3=500℃ respectively. T 1 and T2 The set temperature difference is ≤60° C. The three reaction nozzles extend from the center to the edge in sequence, T1 is the processing temperature of the center of the silicon wafer, and T3 is the processing temperature of the edge of the silicon wafer.

[0020] During the heating process, the temperature at the edge gradually increases at a gradient of 57°C; the temperature at the center gradually increases at a gradient of 62°C.

[0021] Step 4: A layer of SiO2 film, namely LTO, is coated on the back of the silicon wafer with a thickness of 0.45μm.

[0022] Step 5: After the silicon wafer is back-sealed, clean it again. Use SC-1 solution to clean for 11 minutes; then use HF solution with a concentration of 0.25% for 9 minutes; wash with pure water for 11 minutes and dry for later use.

[0023] Step 6: The silicon wafer after APCVD processing is used for subsequent polishing and cleaning.

[0024] In summary, the processing technology for improving the appearance of silicon wafer back seal has the advantages of convenient process operation and good stability of back seal film formation. By improving the process parameters of the APCVD back seal product processing process, powder stains attached to the surface of the wafer after processing are avoided, and the film is uniform without other appearance abnormalities. The first-time processing finished product yield of the product is improved.

[0025] 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 processing technology for improving the appearance of silicon wafer back seal, characterized in that The steps are as follows: Step 1: Clean the double-sided polished silicon wafer before APCVD processing; Step 2: The silicon wafer enters the machine for SiO2 film formation reaction, and the wafer transfer speed is 190-210 mm / min; Step 3: The temperatures of the three reaction nozzles for APCVD processing are set to T1=620~700℃; T2=560~640℃; T3=460~540℃; Step 4: A layer of SiO2 film, i.e. LTO, is coated on the back of the silicon wafer, with a thickness of 0.3 to 0.6 μm; Step 5: Clean the silicon wafer again after back sealing; Step 6: The silicon wafer after APCVD processing is used for subsequent polishing and cleaning.

2. The process for improving the appearance of silicon wafer back seal according to claim 1, characterized in that: Silicon wafers are cleaned before APCVD processing and again after back sealing, both with SC-1 solution for 5 to 15 minutes; then with HF solution at a concentration of 0.1 to 0.4% for 5 to 15 minutes; washed with pure water for 5 to 15 minutes and then dried for use.

3. The process for improving the appearance of silicon wafer back seal according to claim 1, characterized in that: The gas flow ratio of the reaction gas SiH4 to O2 ranges from 1:6 to 1:

16.

4. The process for improving the appearance of silicon wafer back seal according to claim 1, characterized in that: The T 1 and T2 The set temperature difference is ≤60℃.

5. The process for improving the appearance of silicon wafer back seal according to claim 1 or 4, characterized in that: The three reaction nozzles extend from the center to the edge in sequence, T1 is the processing temperature of the center of the silicon wafer, and T3 is the processing temperature of the edge of the silicon wafer.

6. The process for improving the appearance of silicon wafer back seal according to claim 5, characterized in that: During the heating process, the temperature at the edge gradually increases according to the gradient of 55°C to 60°C; the temperature at the center gradually increases according to the gradient of 60°C to 65°C.