A breakthrough in lithography is necessary to realize lower submicron devices beyond 64Mbit dynamic random access memories (DRAMs) due to limitations set by the required depth-of-focus and the k1/square-root k2 value, which represents the total performance of resist materials. An ultimate super resolution imaging system optimized by using a Monte Carlo-like method has been proposed to meet this point-of-view, which suggests that 64 and 256Mbit DRAMs can be realized by i-line and KrF excimer laser exposures, respectively. In addition, a novel chemically amplified resist has been developed using a newly synthesized dissolution inhibitor, t-butylcarbonate derivatives of o-cresolphthalein, which increases the dissolution rate contrast by the self-solubility acceleration effect.