Experimental and Theoretical Study on the Influence of Fatty Alcohol Polyoxyethylene Ether on the Surface Roughness of Silicon in Alkaline Solutions

Abstract

In the final polishing process of silicon, it is susceptible to alkaline anisotropic chemical etch and may have residual silicon sol on the surface, leading to an increase in the surface roughness of the wafer. To address this issue, this study investigates the mechanisms of how fatty alcohol polyoxyethylene ether AEO-9 and O-20 affect the surface roughness of silicon through systematic experimental measurements and theoretical calculations. The research results demonstrate that both AEO-9 and O-20 exhibit strong molecular activity and can adsorb on the silicon surface in a parallel manner, forming a protective film that effectively shields against corrosive particle erosion. Additionally, AEO-9 and O-20 can enhance the wetting of corrosive solutions on the silicon surface, resulting in more uniform chemical etch and reduced formation of etching pits. Furthermore, AEO-9 and O-20 can reduce the residual silicon sol on the silicon surface, thereby decreasing surface roughness. These findings shed new light on how AEO-9 and O-20 affect surface roughness on silicon, and suggest their potential use in the final polishing of silicon wafers.