Development of a chemically amplified positive resist material for single-layer deep-UV lithography

The chemistry and preliminary lithographic characteristics of chemically amplified positive acting (CAMP) resist formulations that meet the deep-UV lithography requirements of low optical density and high sensitivity were described recently.11 This paper examines the lithographic performance of a specific resist comprised of poly (t-butoxycarbonyloxystyrene-sulfur dioxide) and the onium salt, triphenylsulfonium hexafluoroarsenate as the photoacid generator. The lithographic performance was evaluated as a function of resin molecular properties, sensitizer loading effects and various process parameters. Exposures of optimum formulations of this resist (CAMP) were conducted on a GCA prototype deep-UV exposure tool with a NA = 0.35 and 5X reduction optics. Line/space patterns down to 0.35p.m with vertical wall profiles and 0.4.tm windows in 1-1.2im thick films were obtained. The paper will summarize the resolution, depth of focus, exposure latitude and processing characteristics obtained from the evaluation of CAMP and will discuss the pattern transfer results obtained with different substrates. The performance of CAMP was also evaluated on substrates with topography and the results will be presented.