Boundary conditions and solution for Si and poly-Si pitting defects induced by ion implanted PR popping during dry strip process

This paper presents our study on the new mode of yield loss caused by Si and poly-Si pitting defects. This is due to ion implanted photoresist popping during high temperature dry strip process as a result of insufficient PR treatment, which exposed these areas to fluorine radicals attack. It was found that for popping to occur during dry strip process, two factors need to be considered, i.e. in terms of ion implant dosage and photoresist coverage, where both must be fulfilled. The solution to prevent Si and poly-Si pitting defects is also discussed and provided in this paper.