A Solution to Resist Poisoning in the Integration of 248 and 193 nm Photoresist with Low-k Dielectric Materials

摘要

This article presents a general solution to the resist poisoning problem in 248 and 193nm resists integrated with low k dielectrics in VFTL process. This study investigated the interactions of various 248nm and 193nm photoresists with spin-on low-k materials. Two kinds of experiments were conducted: (ⅰ) material characterization involving blanket film/s on bare Si wafers, and (ⅱ) interactions in the dual-damascene full via-first trench-last (VFTL) stacks. The first study facilitates a fundamental understanding of material interactions. This basic understanding can be then extended to high-resolution patterning. In particular, the VFTL process that involves photoresists, anti-reflective coatings, low-k materials, and hard masks was studied. The effects and interactions of via plasma etch and ash processes on subsequent trench lithography steps was also investigated. This article will present experimental results and strategies to reduce or eliminate photoresist poisoning in the full VFTL process.