Study on Resist Removal Using Electrolyzed Sulfuric Acid Solution in Comparison with SPM

Abstract

It is known that resist removal capability of SPM gradually deteriorates during the stripping process. The deterioration is theoretically explained to be the decrease in the concentration of sulfuric acid. On the contrary, in the case of electrolyzed sulfuric acid method, both concentrations of sulfuric acid and of peroxodisulfuric acid produced by electrolysis are kept constant, so that the resist removal capability is maintained for a long term even without addition of hydrogen peroxide. It is proved that resist patterned on φ300mm wafers and implanted at 1E14 atoms/cm2 can be removed using electrolyzed sulfuric acid solution without ashing process.