Polishing agent for synthetic quartz glass substrate

Abstract

Disclosed is a polishing agent for synthetic quartz glass substrates, which is characterized by containing a colloidal solution of a colloidal silica or the like having a colloid concentration of 20-50% by mass, and a polycarboxylic acid polymer, an acidic amino acid, a phenol or a glycosaminoglycan.

Description

TECHNICAL FIELD[0001]This invention relates to a polishing slurry for use with synthetic quartz glass substrates for main use in semiconductor-related electronic materials, nano-imprint-related materials, and display-related materials, especially synthetic quartz glass substrates for use in the advanced semiconductor-related electronic materials and liquid crystal-related materials.BACKGROUND ART[0002]Qualities of synthetic quartz glass substrates include the size and density of defects on substrates, flatness, surface roughness, photochemical stability of material, and surface chemical stability. Of these, the quality relating to defects on substrates encounters increasingly rigorous requirements in accordance with the trend of IC technology toward finer feature size processing and of display panels toward larger size.[0003]While improvements in the defective quality of synthetic quartz glass substrates have been continuously made, the substrates used so far in the semiconductor te...

AI Technical Summary

Benefits of technology

[0021]In the manufacture of synthetic quartz glass such as synthetic quartz glass substrates for forming photomasks to be used in the photolithography that is important in the manufacture of IC or the like, according to the invention, the formation of defects on the surface of synthetic quartz glass substrates which are detectable by the high-sensitivity defect inspector is inhibited, an increase in the yield of manufacture of semiconductor devices or the like is expectable, and a further reduction of feature size in the semiconductor industry is achievable.

[0022]Also, for photomask-forming synthetic quartz glass substrates with end faces having a certain thickness used in display-related materials, the invention inhibits the formation of defects during polishing and improves the yield of manufacture.

Problems solved by technology

This leads to a delay in the substrate quality improving approach.

While JP-A S64-40267 (Patent Document 3) describes a process of polishing a glass substrate with colloidal silica to produce a precise mirror finish surface, this was found unsatisfactory as the microscopic defect controlling process because an analysis of surface defects by said high-sensitivity defect inspector demonstrated the presence of microscopic raised / recessed defects.

However, when synthetic quartz glass substrates are polished in the above-described concentration range, numerous defects with a size of up to 0.5 μm are generated.

It is then undesirable as the polishing slurry for photomask-forming glass substrates.

In fact, it is impossible to use such colloidal silica in the neutral range in a consistent manner because even those high purity products having minimal contents of metals and other impurities tend to gel or thicken or change the particle size distribution of abrasive grains with iteration of polishing.

Accordingly, such a process has a serious issue that recycling of the polishing slurry for repeated use is difficult, and inevitably the polishing slurry has to be utilized as a one-way stream, which is unfavorable in economical and environmental aspects.