Evaluation and application of resist for alkaline wet etching

ProTEK PSB and ProTEK B3 (Brewer Science, Inc.) are negative type photosensitive resist and non-photosensitive resist for alkaline wet etching, respectively. This paper mainly reports the patterning characteristics, etch resistance and removal characteristics of ProTEK PSB under practical conditions for a real application. Our study found two problems of ProTEK PSB: unacceptably-large side-etching and difficulty in removing the primer by organic solvents or O₂ ashing. For the fabrication of a LSI-integrated tactile sensor, we used ProTEK PSB with a low temperature oxide underlayer. This combination solves both side etching problem for ProTEK PSB and pinhole problem for low temperature oxide, providing the practical alkaline etching mask which can be prepared at low temperature.