Method for removing polished section crystal round edge used for IGBT (insulated gate bipolar transistor) in a row grinding manner

Abstract

The invention relates to a method for removing a polished section crystal round edge used for an IGBT (insulated gate bipolar transistor) in a row grinding manner. The method is characterized in that a special cutting edge machine is applied to a polished section crystal round edge oxide film treatment process, and firstly, a package plastic blue film is adhered on a silicon die back surface through a pyrocondensation machine; the special cutting edge machine marks different sizes of roundness incisions on the plastic blue film adhered on the silicon die back surface according to different specification of a silicon slice, the annular roundness plastic blue film required to be corroded is torn up along the incisions, thereby protecting the part of which a back sealed Si02 film is not required to remove; the row ground type cutting edge technology can be used for preparing a raw material substrate of an epitaxial wafer used for electric power electron devices such as IGBT and the like;and the method provided by the invention has the advantages of simple operation, low cost, high production efficiency, strong practicability, and is technology which is suitable for removing the backSi02 film in large-scale industry production.

Description

technical field [0001] The invention relates to a back treatment technology of a semiconductor wafer silicon polishing sheet, in particular to a method for removing an oxide film on the edge of a polishing sheet used for IGBTs by means of scratching. Background technique [0002] With the rapid development of China's economy, various domestic infrastructure and energy construction are in a period of rapid development. A number of national key projects that have a huge stimulating effect on the national economy, represented by the State Grid Project, high-speed rail transit, electric vehicles and hybrid vehicles, and green energy-saving industries, all have strong demand for new power electronic devices. With the rapid growth of new power electronic devices represented by IGBT, the development of polished silicon wafers, the raw material substrate for IBGT epitaxial wafers, provides a broad market space and rare opportunities. The processing of polished silicon wafe...

AI Technical Summary

Problems solved by technology

Edge oxide film removal is an important process in the processing of silicon wafer polishing, which plays a vital role in the yield of polished wafers, subsequent epitaxy and IGBT devices: chamfers, silicon wafers caused by the back-sealing process Front SiO 2 Residues, even SiO on the back edge of the wafer 2 Residues may become nucleation centers during epitaxial growth, forming polycrystalline and amorphous (amorphous silicon) at the edge; thus affecting the quality of epitaxial growth and reducing the effective area of ​​epitaxial growth

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 wafer manufacturers have their own limitations in the edge oxide film removal treatment 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 (abbreviated in the text) Reaction chamber edge removal technology), the disadvantage of this technology is that HF ​​gas is volatile, and a large amount of HF will be consumed for one corrosion, which is not conducive to cost control, and may also cause harm to operators; in addition, the range of HF removal cannot be precisely controlled, which may cause Back-sealed SiO in the center of the backside of the silicon wafer 2 remove the membrane

[0004] Method 2: Align the rack with the silicon wafers on the runner, so that the silicon wafers are in contact with the runner (referred to as the roller-type edge removal technology in the text); use the runner to drive the rack with the silicon wafers to rotate, and the runner There is an HF groove under the wheel, and while the wheel is rotating, the SiO on the edge of the silicon wafer 2 The film is etched by HF; this technique ensures that the back-sealing SiO 2 The film is not removed, but since the HF liquid is always flowing, this method is difficult to precisely control the HF on SiO 2 The removal range of the film and its edge removal range are often uneven, and the processing pass rate is low

[0005] Method 3: Adhere the round 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-sealed SiO 2 Part of the 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, thereby limiting the use of HF, and can accurately Controlling HF on SiO 2 However, since the special circular plastic blue film is monopolized by a small number of manufacturers, the cost is usually very high; and the precision control of this process depends entirely on whether the manual attachment of the circular plastic blue film is accurate, and the operating requirements for the operator It is very high, which is not conducive to mass production; in addition, due to the limited specifications of the circular plastic blue film, it often cannot meet the production needs of the actual wafer edge oxide film removal

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