A supercritical carbon dioxide silicon block cleaning device, silicon block processing system and method

Abstract

The invention relates to the technical field of semiconductor processing, in particular to a supercritical carbon dioxide silicon block cleaning device, comprising: a tank body providing a closed space for cleaning silicon blocks; It is based on the supercritical pressure of carbon dioxide, and keeps the pressure constant during the cleaning process; and, after the silicon block is cleaned, the pressure in the tank is reduced to make the carbon dioxide vaporize; the temperature control device, before the silicon block is cleaned, the closed space The temperature is adjusted to be higher than the supercritical temperature of carbon dioxide, and the temperature is kept constant during the cleaning process; the compression device compresses the gasified carbon dioxide from the tank to form liquid carbon dioxide; the carbon dioxide storage tank performs liquid carbon dioxide Storage, supply and recycling. Through the invention, the residues in the micropores of the silicon block can be effectively flushed out, so that the impurities on the surface of the silicon block are qualified. The invention also claims a silicon block processing system and method.

Description

technical field [0001] The invention relates to the technical field of semiconductor processing, in particular to a supercritical carbon dioxide silicon block cleaning device, a silicon block processing system and a method. Background technique [0002] Electronic-grade polysilicon is the basic raw material of the integrated circuit industry. In order to ensure high purity, the improved Siemens method is generally used to remove impurities from the liquid raw material trichlorosilane through rectification and other purification methods, and then produce it through chemical vapor deposition in the reduction furnace. . The products produced in the reduction furnace are polysilicon rods, which cannot be directly drawn by downstream silicon wafer customers. They need to be crushed into polysilicon blocks of appropriate size, but trace impurities are easily introduced during the crushing process. Compared with The ultra-high purity requirements of the polysilicon body are unacce...

AI Technical Summary

Problems solved by technology

The products produced in the reduction furnace are polysilicon rods, which cannot be directly drawn by downstream silicon wafer customers. They need to be crushed into polysilicon blocks of appropriate size, but trace impurities are easily introduced during the crushing process. Compared with The ultra-high purity requirements of the polysilicon body are unacceptable, so the surface needs to be cleaned

[0003] The commonly used cleaning methods use various acids or mixed acids to etch the surface of silicon blocks, but in the process of etching, it is easy to cause uneven etching, stains or other surface abnormalities due to the difference in surface microstructure. At the same time, it is easy to make the appearance of the silicon block poor due to the difficulty of process control

In addition, after using acid for surface etching, high-purity water needs to be used for rinsing to clean the acid residue and impurities, and then it needs to be dried. In this process, incomplete rinsing and drying are very likely to occur, making silicon Impurities on the surface of the block exceed the standard, resulting in failure of crystal pulling in downstream applications

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