The present invention relates to norbornene monomers with a novel functional group containing an organometal as shown in the following Formula (I) or (II), a photoresist containing its polymers, manufacturing method thereof, and a method of forming photoresist patterns. ##STR1## Unlike existing polymers for photoresist matrix, polymers made by norbornene monomers described in the present invention is a chemical amplification type induced by photosensitive acids and can result in difference in silicon content between the exposed area and unexposed area due to dissociation of side chain containing silicon. The difference in the silicon content results in different etch rate with respect to oxygen plasma which makes dry developing possible.