Method of disposing of insulated gate bipolar translator (IGBT) silicon wafer polishing piece edge oxidation film in extrusion mode

Abstract

The invention relates to a method of disposing of an insulated gate bipolar translator (IGBT) silicon wafer polishing piece edge oxidation film in an extrusion mode and applies a specialized extrusion trimming machine to the treatment process of the silicon wafer polishing piece edge oxidation film. The method of disposing of the IGBT silicon wafer polishing piece edge oxidation film in an extrusion mode includes: 1, aligning a silicon wafer back seal face and a rubber ring spacer rubber ring face, arranging a reference surface down, placing the silicon wafer back seal face and the rubber ring spacer rubber ring face on a positioning table of the extrusion trimming machine to position; 2, enabling the positioned silicon wafer and the rubber ring spacer to be pressed tightly through turning a threaded extrusion rod; 3, placing the extrusion trimming machine clamping the silicon wafer and the rubber ring spacer on a cavity filled with hydrogen fluoride (HF) steam or dipping the clamped silicon wafer and the rubber ring spacer into the HF solution partially, shaking a rocking handle to enable an extrusion plate at the right side to rotate; 4, rinsing the residual HF on the surface of the silicon wafer, separating the silicon wafer and the rubber ring spacer. The method of disposing of the IGBT silicon wafer polishing piece edge oxidation film in an extrusion mode is capable of accurately controlling the elimination range of HF to a Sio2 film, improving production efficiency, lowering cost, benefit for production a large range and capable of meeting the production requirement of eliminating silicon wafer polishing piece edge oxidation film of any specification.

Description

technical field [0001] The invention relates to the back treatment technology of a semiconductor silicon wafer polishing sheet, in particular to a method for removing an oxide film on the edge of a silicon wafer polishing sheet for IGBT by means of extrusion. Background technique [0002] The processing of polished silicon wafers generally includes slicing, chamfering, grinding, etching, back treatment, polishing, and cleaning processes. The back treatment process generally includes back damage treatment, back sealing treatment and edge oxide film removal treatment. Edge oxide film removal is an important process in the processing of silicon wafer polishing, which plays a vital role in the yield of silicon wafer polishing and subsequent epitaxy and IGBT devices: the chamfered surface caused by the back sealing process , SiO on the front side of the silicon wafer 2 residues, even SiO on the backside edge of the silicon wafer 2 Residues may become nucleation centers in the ...

AI Technical Summary

Problems solved by technology

The lattice defects at the edge of the epitaxy can cause the edge yield of the device to be low

[0003] Unfortunately, at present, domestic silicon wafer polishing wafer manufacturers have their own limitations in edge oxide film removal technology: usually include the following methods: method 1 is : Use HF gas to remove the oxide film on the edge of the silicon wafer in the reaction chamber (hereinafter referred to as the reaction chamber edge removal technology). The disadvantage of this technology is that the HF gas is volatile, and a large amount of HF is required for one etching, which is not conducive to cost control. , may also cause harm to the operator; in addition, the HF removal range cannot be precisely controlled, and the back-sealing SiO2 film in the center of the back of the silicon wafer may be removed together

Method 2: Align the rack with silicon wafers on the runner, so that the silicon wafer is in contact with the runner (herein referred to as the roller-type edge removal technology); use the runner to drive the When the rack rotates, there is an HF groove under the wheel. While the wheel rotates, the SiO2 film on the edge of the silicon wafer is etched by HF; although this technology can ensure that the back center The back-sealing SiO2 film is not removed, but because the HF liquid is always flowing, it is difficult to accurately control the removal range of the SiO2 film by HF and the edge removal range. Its edges are often uneven, and the processing pass rate is low

Method 3: Adhere the circular plastic blue film that is not corroded by HF to the surface of the silicon wafer and the suction cup by manual attachment (referred to as the hand-applied film edge removal technology in the text), and the silicon wafer does not need to be removed from the back seal. Part of the SiO2 film is protected, and then placed in HF acid vapor or HF liquid to remove the edge back-sealing silicon dioxide film; this method can control the removal time of HF acid vapor, In this way, the use of HF is limited, and the removal range of SiO2 film by HF can be precisely controlled; however, since the special circular plastic blue film is monopolized by a few manufacturers, the cost is usually very high; and the process Accuracy control depends entirely on the accuracy of the artificially attached round plastic blue film, which has high requirements for operators and is not conducive to mass production; in addition, due to the limited specifications of the circular plastic blue film, it often cannot meet the actual wafer edge oxidation. Production needs for membrane removal

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