Safe-Solvent Alternatives for E-Beam Resists and Developers

Much effort is being devoted toward extending the resolution capability of lithographic technologies to obtain sub 0.25 micron capability. At the same time there are concurrent research programs to develop sub 0.25 micron devices using prototype imaging techniques, such as e-beam lithography. Many advanced devices with Defense applications are manufactured in compound semiconductor materials such as Gallium Arsenide where poly(methylmethacrylate) (PMMA) resists are widely used. Environmental concerns and public awareness have led to legislation encouraging the replacement of hazardous and ozone depleting chemicals in the workplace. In many cases this means the replacement of existing process chemicals, including PMMA resists and developers, with newer "safe-solvent" alternatives. We propose to focus our effort on the evaluation of suitable "safe-solvent" alternatives for the PMMA and P(MMA-co-MAA) resist systems in processes for which they are most widely used. In these bi- and tri-layer coatings there must be little or no intermixing between the layers during the coating process. We propose in Phase I to conduct a systematic study to evaluate the performance of selected materials and determine the most promising one or two systems for further characterization. Phase II will be used to develop and optimize the process using these systems for a range of applications.