Defect analysis of Cl2/HBr/He/O2 etching process by imaging time-of-flight secondary ion mass spectrometry

Abstract

Defects appeared during Cl2/HBr/He/O2 etching process were investigated by high laterally resolved imaging time-of-flight secondary ion mass spectrometry (TOF-SIMS). The defects with size of one to several microns appeared after the etching process. These defects are electron-beam sensitive during Auger electron spectroscopy and energy dispersive spectrometry analysis. Imaging TOF-SIMS clearly shows that the defect consists of bromine and H2O. Relatively weak oxygen and silicon signals were detected from the defect site. A negative secondary ion mass spectrum from region of interest (ROI) analysis of the defect area shows a very strong Br− signal. A positive secondary ion mass spectrum from ROI analysis has a very strong H2O+ signal from the defect. These results amply demonstrate that imaging TOF-SIMS enables chemical analysis of small defect at outmost surface with high lateral resolution and submonolayer sputtering damage under static SIMS analytical conditions.