Sapphire polishing waste liquid reuse method

Abstract

The invention relates to a sapphire polishing waste liquid reuse method. The invention relates to a method for polishing a high-k metal gate. The polishing liquid for polishing the high-k metal gate is the sapphire polishing waste liquid which has been used for polishing for more than 1h. The sapphire polishing waste liquid contains silicon dioxide grinding particles with particle size between 1-1000nm. The pH value of the sapphire polishing waste liquid is between 9-11. With the method provided by the invention, the high-k metal gate requirement of ultrahigh Al/SiO2 polishing selection ratio can be satisfied, and sapphire polishing waste liquid retreatment can be realized.

Description

technical field [0001] The invention relates to a method for reusing sapphire polishing waste liquid, and is also a new method for polishing high-k metal grids. Background technique [0002] With the promotion of energy-saving lamps and intelligent terminal equipment, sapphire substrates have been more and more widely used. Sapphire is hard (9 on the Mohs scale, second only to diamond), chemically inert, and difficult to machine. However, in order to achieve the required mirror effect, it usually still takes several hours to carry out chemical mechanical polishing and fine polishing process. At present, there is a large demand for sapphire fine polishing liquid. For example, many large sapphire factories need tens or even hundreds of tons of fine polishing liquid per month. At the same time, waste liquid treatment has become a difficult problem. Colloidal silicon dioxide (SiO 2 )-based alkaline sapphire polishing waste liquid, direct dumping does not meet the environment...

AI Technical Summary

Problems solved by technology

Colloidal silicon dioxide (SiO 2 ), usually only 100 magnitudes of Al to SiO can be obtained 2 The polishing selection ratio of the material is high, but the polishing liquid system is stable and there are few defects after polishing; w

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