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

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 O 2 plasma is well known to cause yield reduction and reliability deterioration. This paper investigates a PR strip method using ozone (O 3 ) 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 1.3 mega-pixel complementary metal oxide semiconductor image sensor fabricated with 0.18 μm technology node.