A high contrast single layer i-line resist process was developed using Aspect Systems 9 resist for a GCA 5X wafer stepper equipped with a Tropel 20 mm diameter, 0.40 NA lens. The process development sequence is described, where surface response experiments are used to evaluate the effects on resist contrast of process factors. These factors include prebake time and temperature, post exposure bake time and temperature, metal-ion free developer concentration, develop time, and develop temperature. Contrast is found to depend upon standing wave interference. Results of a factorial comparison of the single layer process for critical dimension control with and without CEM 388 made for site-to-site and wafer-to-wafer variations yielded similar results. SEM micrographs for the optimized single layer process illustrate near verticle resist profiles with good depth of focus latitude, and agree well with PROSIMulations except under large defocus conditions. The optimized single layer resist process has been employed to evaluate a new Tropel 20 mm diameter, 0.40 numerical aperture, i-line lens with good results.