A UNIFIED APPROACH TO RESIST MATERIALS DESIGN FOR THE ADVANCED LITHOGRAPHIC TECHNOLOGIES

New resist materials and processes are necessary to pattern less-than-or-equal-to 0.25 mum design rule circuits with advanced deep-UV, X-ray and e-beam lithographic technologies. Chemically amplified positive resist systems introduced to meet the high sensitivity and resolution requirements of the deep-uv, e-beam and x-ray exposure tools suffered from marginal adhesion, poor etch resistance and deteriorating process performance with post-exposure delay (PED) time. Improved resist systems such as those based on materials poly(4-acetoxystyrene-4-t-butoxycarbonyloxystyrene-sulfone) (PASTBSS) terpolymers resolved the adhesion problems and improved the etch resistance and post-exposure delay time stability. Theses resists, however, still required a covercoat for good process performance. Additionally, all the current commerical chemically amplified positive resists show varied degrees of ''foot'' formation on Titanium Nitride and Silicon Nitride substrates and strong linewidth dependence on PEB temperature (large DELTAlw/-degrees-C). We have developed a new multi-component positive chemically amplified resist called ARCH (Advanced Resist CHemically Amplified), that in addition to exhibiting excellent resolution with deep-uv, x-ray and e-beam exposures, displays no noticeable foot on Titanium Nitride, Silicon Nitride and BPSG substrates. Initial results with deep-uv lithography also indicate that linewidth dependence on post-exposure bake (PEB) is minimal. This chemically amplified resist system exhibits linear 0.25 mum resolution with a GCA XLS excimer laser stepper (0.53 NA, 248 nm) and 0.14 mum resolution with a pulsed laser point source proximity print x-ray stepper (lambda centered at 1.4 nm) and 0.1 mum resolution with a JEOL JBX-5DII e-beam exposure system (at 50 keV).