Analysis of amine contamination on silicon oxide surfaces using ToF-SIMS

Abstract

Contamination detection and control play a critical role in achieving the semiconductor industry’s roadmap. Compared to metal and particle contamination, knowledge on organic contamination and its detrimental effects is still limited. As the devices are continuously scaled down, organic contamination is increasingly become a major yield-affecting factor. Previous studies of organic contamination on silicon oxide surfaces have focused on total carbon contamination and its effects on gate-oxide integrity. During wafer fabrication process, there are many possibilities for organic contamination. Wet cleaning-induced organic contamination is one of them. In this paper, amine contamination on silicon dioxide surfaces caused by wet cleaning is investigated using thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). A semi-quantitative method is adopted to evaluate amine contamination on silicon oxide surfaces. The amount of amine contamination on the oxide surfaces depends on the wet cleaning process and wafer storage conditions. The effect of amine contamination on the photoresist poisoning is also discussed.