A novel photoresist stripper for bumping technology

Both liquid film and dry film photoresists are used broadly in bumping technology. As of today, different strippers are used to remove them separately, which adds extra cost in handling different photoresist consumables in different process schemes. In this paper, a well-designed and unique stripper is introduced to address liquid film and dry film photoresist strip compatibility issue in mixed solvents system. The results indicate the stripper can remove both liquid film and dry film photoresists at the same operation temperature. Through the dissolution mechanism, the bumps and Cu substrate are well protected under different process time.