Formulation and Evaluation of Diluted Sulfuric-Peroxide-HF (DSP+) Mixtures for Cleaning High-Aspect Ratio Contacts in 3D NAND

In this study, organic strip, particle removal efficiency and wettability were investigated at different mixing concentrations of diluted Sulfuric-Peroxide-HF (DSP + ) solutions with and without the addition of IPA. Organic strip evaluation was carried out with KrF photoresist (PR), and the strip rate was increased rapidly with the increase in H 2 SO 4 concentration mixed with DI water (DIW). The effects of H 2 O 2 and IPA addition on diluted H 2 SO 4 were observed below 30 vol% of H 2 SO 4 . The thickness of PR was increased with the addition of H 2 O 2 to the solutions and the strip rate was increased when IPA was added. Silica particles were used to evaluate particle removal efficiency. The concentration of HF was the predominant factor of increasing PRE, and the addition of H 2 SO 4 and H 2 O 2 assisted in obtaining high PRE, while IPA addition reduced PRE. Decreasing of contact angle was observed with an increase of IPA addition to DSP + solutions, and improved wettability of DSP + solutions was expected to effectively clean particles in high-aspect-ratio (HAR) contact holes.