Plasma-Damage-Induced Leakage Prevention Using Ozone Followed by SPM Solution Cleaning for Ion-Implanted Photoresist Strip

Abstract

During the device fabrication, thin dielectric layers experience a wide range of photoresist (PR) strip processes after various implantations carried out with the thin dielectric layers exposed. Degradation of the thin dielectric layers by the PR strip process using plasma is well known to cause yield reduction and reliability deterioration. This paper investigates a PR strip method using ozone followed by sulfuric-peroxide mixture (SPM) solution cleaning and finds it significantly effective in PR strip performance even at the damaged PR by high-dose and high-energy implantations. The method dramatically reduces gate leakage current, resulting in significant improvement in gate oxide integrity. The PR strip technology is significantly effective for the reduction of plasma damage-induced dark current and white pixel defects of a complementary metal oxide semiconductor image sensor fabricated with technology node.