Temperature rising effect of 193-nm chemically amplified resist during postexposure bake

The deprotection of chemically amplified resist is amplified by photogenerated acid during post exposure bake. The deprotection rate is mainly dependent on bake temperature and time. It has been assumed that the temperature of wafer surface and photoresist is to be raised instantaneously up to desired set temperature, but in real world it can not happen. We investigated the temperature change of wafer surface on a hot plate and obtained effective post exposure bake time. We applied the effective post exposure bake time to our simulation tool and the simulation results showed a better agreement with the experimental resist profile.