Improved photolithography process using two photoresist layers for device fabrication.

摘要

An improved two layer photolithographic process is disclosed for use in the construction of an integrated circuit structure. The improvements comprise applying over a first photoresist layer sensitive to light below about 250 nm a second photoresist layer containing a selective solvent which is not a solvent for the first photoresist layer to inhibit reaction between the layers to form an interfacial layer therebetween; baking the second photoresist layer at a temperature below the glass transition temperature of the resin in the second photoresist layer to further suppress formation of the interfacial layer; and photostabilizing the remaining portions of the second layer after development at a wavelength range which will crosslink the remaining photoresist in the second layer to permit subsequent development of the lower photoresist layer, after exposure, with a high resolution developer which will not dissolve the crosslinked upper photoresist. The crosslinked portions of the second photoresist layer protect the corresponding patterned portions of the first layer thereunder during subsequent dry etching to prevent erosion of the patterned first photoresist.