High resolution resist structures with steep edges are obtained using standard equipment, even in cases involving critical contact-hole planes. First, a photoresist layer containing a polymer with chemically reactive groups and a photoactive component based on diazoketone or quinone diazide is deposited on a substrate. The photoresist layer is then irradiated with a patterned image and treated with a polyfunctional organic compound having functional groups that can chemically react with the reactive groups of the polymer. This step is followed by a maskless flood exposure. The photoresist layer irradiated in this manner is then treated with a metal-containing organic compound having at least one functional group capable of chemical reaction with the reactive groups of the polymer, followed by etching in an oxygen-containing plasma.