The characteristics of the photoresist (PR) ashing process with respect to the dual damascene structure in its low-k materials scheme were investigated. The O2 plasma used in the conventional PR ashing oxidizes low-k material and makes an SiO2-like layer, which causes the increase of the dielectric constant and the leakage current. The oxygen contributes to damaging the low-k material by breaking the Si-CH3 and C-H bonds and thus by changing the low-k dielectric layer to the SiO2-like material, which can be easily removed by the HF solution. The optimized condition for high PR ashing rate and low ashing damage was achieved with the help of O2/(N2 + O2) gas flow ratio of 0.1. It was observed that the ashing process removes both PR on top of the structure and inside the via hole.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering