Identification and solutions for a novel particulate pollution matter in wafer surface caused by concentrated sulfuric acid

The concentrated sulfuric acid is a necessary chemical for IC-Industry, especially in the wet process. The electronic grade concentrated sulfuric acid offered by major suppliers satisfies the requirements of the new technologies in metal ion impurities and insoluble particulate matters, but during the use of that offered by a core supplier in wet process, a new kind of particle contamination appeared. In this paper, the particulate pollution matter has been confirmed as carbide formed from Siloxane, which was produced at high temperature and strong acidic conditions. In order to control the generation of this new particulate pollutant, TOC (Total Organic Carbon) and Silicon content (Sc) were measured in electronic grade concentrated sulfuric acid, and used to establish the relevant mathematical model for calculating the Sr (Siloxane Relative Value) in electronic grade concentrated sulfuric acid, which was first proposed as a new quality demand for the concentrated sulfuric acid.