We have developed an advanced micro-lithographic process for producing 0.1 µm contact holes (CH). A chemical shrink technology, resolution enhancement lithography assisted by chemical shrink (RELACS) utilizes the cross-linking reaction catalyzed by the acid component existing in a predefined resist pattern. This “RELACS” process is a hole shrinking procedure that includes simple coating, baking, and rinse steps applied after conventional photolithography. We evaluated the dependency of CH shrinkage on resist formulation. Though the acetal type KrF positive resist (low activation energy system) can achieve around 0.1 µm CH after RELACS processing under the optimized condition, the acrylate type positive resist (high activation energy system) showed less shrinkage under the same process condition. The shrinkage performance of the RELACS process largely depends on the resist chemistry used as the underlying layer. The results of these studies are discussed in terms of the influence of the base polymer on shrinkage performance and tendency.