The invention is directed to a method for obtaining a developer solvent for radiation-sensitive negative resists which are used in lithographic processes for the production of electronic microchips.The negative resist polymer is applied to the surface of the microchip substrate directly, or through an appropriate bonding agent layer, in any conventional manner suitable to the particular polymer. Once the resist polymer coating is obtained on the substrate, the resist polymer is irradiated using a suitable radiation source to obtain a latent image therein. The latent image exists within the polymeric resist coating in the form of crosslinked polymer surrounded by areas of nonirradiated, non-crosslinked polymer which must be removed in order to develop the image, thus producing the desired resist pattern on the substrate.Wet development of the image requires the use of solvents capable of dissolving away the non-crosslinked polymer while leaving a substantially undisturbed, undistorted crosslinked polymer image upon the substrate.The present invention provides for use of a developer solvent comprised of a mixture of organic compounds, each of which, when applied singly, acts as a nonsolvent for such non-crosslinked polymer, but which, when applied as a mixture, works as a solvent.Images developed using the developer solvents of the present invention are superior to images produced using development processes of the prior art in that swelling, profile distortion, surface erosion and line irregularity of the developed image are substantially eliminated.