Removal Characteristics of Hillock Defects on Silicon Substrate by Chemical Uniformity Etching Enhanced Polishing Slurry

Abstract

The thermally generated defects will lower the life time in bulk silicon and cause increasing in the leakage current of individual diodes in integrated circuits, that will finally cause the malfunction with advanced devices and IC chips. The removal characteristics of hillock defects on the single bare silicon wafer generated by the thermal process were experimentally analysed with respect to the chemical additives enhanced uniform chemical etching and mechanical abrasion of high pure nano sphere colloidal silica interplaying with the alkali based polishing slurry. During the polishing, it was found that the silicon surface contacted with high speed of rotated polishing pad under the down force pressure is chemically dissolved by the slurry containing FA/O organic polyamine(R(NH2)n) agent with adding proper proportional FA/O I non ions surfactant, which effectively lowered the surface strain of slurry contacted to the reactive surface of the wafer and slurry enhanced uniform chemical etch leading to the hillock region and no hillock region. However, by the process of chemical mechanical polishing，the results show it can eliminate the hillock defects on the surface of silicon wafer thoroughly with high removal rate, and achieve lower surface roughness than before process of polishing.