The use of silver halide emulsion as a resist

Silver halide-gelatin emulsion has been evaluated as a resist for patterning silicon integrated circuits using X-ray, E-beam, and UV exposure. The emulsion is coated on 3" wafers by a dipping process. The pattern exposed in the emulsion is developed, and a tanning agent is used to crosslink the gelatin in regions where silver is precipitated in the gelatin. The uncrosslinked gelatin is then dissolved away. We have been able to pattern 0.5µm lines and spaces in a gel-resist using X-ray exposure. The resist withstands plasma etching of underlying layers of polysilicon and SiO2.