ADVANCED DEVELOPMENT PROCESS FOR ULTRA-FINE PHOTORESIST PATTERNS

Addition of appropriate surfactant to developer will improve wettabili ty of the developer, thus promoting dissolution uniformity of exposed photoresist. Surface smoothness of the Si substrate is also improved w hen developer contains surfactant. The only disadvantage is that surfa ctant is adsorbed onto the water surface; however, it can be removed b y a Pt-H2O2 treatment without degrading the photoresist pattern. The o ptimal tetramethylammonium hydroxide (TMAH) concentration in the devel oper was investigated by measuring the developing selectivity of the p hotoresist against various TMAH concentration levels. The developing s electivity is considered to directly affect the photoresist profile an d resolution in the development process.