The Bell Laboratories electron-beam exposure system (EBES) is currently being used to fabricate master masks and experimental devices using a negative resist based on poly(glycidyl methacrylate-co-ethyl acrylate) (COP) and a positive resist, poly(butene-1-sulfone) (PBS). COP was designed to have a sensitivity of 2-4 multiplied by 10** minus **7 C cm** minus **2 and good wet chemical etching resistance for a variety of thin-film conductors and insulators. The resolution obtained with a 0. 6- mu m initial COP film exposed with EBES and processed on a routine line is 2. 0 mu m. These characteristics are satisfactory for current requirements; soon however, machine improvements, smaller device geometries, and new processing procedures are going to place increasing demands on resist systems. In addition to resolution requirements, it is desirable to have a resist which is resistant to ion beam milling, plasma etching, or other dry etching techniques. Each of these requirements will be discussed in detail. This paper summarizes the results of the synthesis and initial lithographic evaluation of several potential negative electron resist systems. These resists were designed to have higher resolution and improved dry etching resistance than the negative resist, COP. Specifically copolymers of glycidyl methacrylate and/or glycidyl acrylate with styrene, and phenyl methacrylate will be discussed.
