Feasibility Study of Silylation Process for Submicron Manufacturing

Abstract

Surface imaging using silylation treatment is explored with the aim of understanding the size of the process window for submicron lithography. The influences of resist materials and process temperature were investigated. Resist material strongly influenced the quality of imaging. However, the optimum processing conditions for the conventional diazoquinone/novolac resist and specially formulated dry develop resist were similar. Soft bake temperature, presilylation bake temperature, and silylation bake temperature strongly influenced critical dimension (CD) control in the temperature regimes investigated. The large effect of presilylation bake and silylation bake temperature on CD control can probably be overcome by driving the diazoquinone induced cross linking reaction to completion. However, it is unclear whether a similar scheme will control the 0.025μm per degree centigrade line width variation with soft bake temperature. Considering both the depth of focus and exposure latitude data, the dry develop process appears to conservatively extend the manufacturable resolution to a k of about 0.65 in the Rayleigh resolution equation. At this resolution, our data indicate a depth of focus of about 1.5μ to 2.0μ and an exposure latitude of about 30% (for 0.6μ lines/spaces printed with a 0.40 NA i-line stepper).