Purification method of ultra-pure silicon dioxide sol

Abstract

The invention discloses a method for purifying a silica sol with superhigh purity in the technical field of chemical mechanical polishing. The purification process comprises taht: strong acid type cation exchange resin, strong alkali type anion exchange resin and strong acid and strong alkali mixed-bed resin are filled to an ion exchange column and are subjected to regeneration treatment; the temperature of the silica sol is controlled between 0 and 60 DEG C and inversely flows through a strong acid type cation exchange bed; the obtained acid silica sol inversely flows through a strong alkalitype anion exchange bed and is added with a chelator so that pH of the silica sol is between 1.0 and 3.0; and the silica sol added with the chelator inversely flows through a strong acid and strong alkali ion exchange resin mixed bed to obtain the purified silica sol. The method has good purification effect, can obtain the silica sol of which the superhigh purity meets the requirement of the chemical mechanical polishing, has short purification time and high efficiency, and can be used for continuous industrialized production.

Description

technical field [0001] The invention belongs to the technical field of chemical mechanical polishing, and in particular relates to a purification method of ultra-high-purity silica sol. Background technique [0002] Over the past few decades, a society of beliefs has emerged, built on computers, the Internet, wireless communications, and global positioning systems. The core part of this information society is supported and constituted by many small integrated circuit (IC) chips built into the system, and integrated circuits have been widely used in various fields of life. In the field of electronics manufacturing, Gordon Moore made his famous observation in 1965, known as "Moore's Law". Moore discovered and predicted that the number of transistors on an integrated circuit chip of the same size would double every two years. Moore's Law has had a huge impact on the semiconductor industry and has inspired all practitioners. During the more than 40 years since it was proposed,...

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Problems solved by technology

[0007] (2) Point defects: solvents, alcohols, amines;

However, the raw material (TMOS / TEOS) of this method is more expensive, the cost is higher (the utilization rate of the raw material is less than 30%), and the ethanol or methanol produced by heating pollutes the environment

In addition, although the silica sol prepared by this method has high purity, some ammonia and alcohol remain in the silica sol, which will have an adverse effect on the polishing of the new generation of chips.

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