KEY TECHNOLOGIES IN LOWER SUBMICRON LITHOGRAPHY - ULTIMATE SUPER RESOLUTION IMAGING-SYSTEM AND CHEMICALLY AMPLIFIED RESIST USING THE SELF-SOLUBILITY ACCELERATION EFFECT

A breakthrough in lithography is necessary to realize lower submicron devices beyond 64Mbit dynamic random access memories (DRAMs) due to li mitations 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 C arlo-like method has been proposed to meet this point-of-view, which s uggests that 64 and 256Mbit DRAMs can be realized by i-line and KrF ex cimer laser exposures, respectively. In addition, a novel chemically a mplified resist has been developed using a newly synthesized dissoluti on inhibitor, t-butylcarbonate derivatives of o-cresolphthalein, which increases the dissolution rate contrast by the self-solubility accele ration effect.