DRY TYPE DEVELOPMENT METHOD

PURPOSE:To form a high precision pattern, by executing electron beam patternwise exposure and ultraviolet ray irradiation on a positive type resist. CONSTITUTION:An electron beam positive type rsist decreasing in molecular weight under electron beam irradiation and increasing in molecular weight under its high irradiation is coated on a substrate, the resist is patternwise exposed to electron beams, and the unexposed part to the electron beams and the weakly exposed part are removed by irradiation of ultraviolet rays. In the figure, (a), (b), (c) represent changes of molecular weights of polymethyl methacrylate, polyhexafluoro- methacrylate, and polytetrafluoropropylmethacrylate, respectively, and in the case of the small irradiation region, the main chain is cut and the molecular weight decreases. Under the intense irradiation, cross-linking reaction occurs, the molecular weight increases, but the product is different in ractivity and physical property from the undeveloped part because of the side reactions different from the cross- linking reaction of the negative type resist. The parts except the electron beam exposed part are decomposed and removed.