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The demand for smaller device dimensions in microlithography drives the need to understand and control diffusion during photoresist processing. In advanced chemically amplified systems the lithographic performance is strongly influenced by diffusion of acid and base additives. Photoacid generation efficiencies and diffusion parameters were quantitatively evaluated using an established in situ photometric method employing a pH-sensitive organic dye. [ 1-3 ] A kinetic model for the post-exposure bake (PEB) has been proposed, transferred to molecular reaction dynamics and extanded to transport properties. The experimental data for this model have been obtained from UV/VIS spectroscopy measurements. The UV/VIS data show that a photoacid loss reaction during post-exposure bake has to be taken into account. Rough estimations of the acid diffusion lengths are given by the rate of the diffusion-controlled neutralization reaction for blanket exposures. The acid diffusion range was minimized, as the temperature of pre baking was raised and the PEB temperature was reduced. Chemical kinetics around the glass transition temperature of the resist are discussed. Furthermore, a face-to-face contact experiment (wafer-sandwich) involving the dye was used to determine acid loss during PEB. Comprehensively, the acid diffusion within the matrix and acid evaporation out of the matrix could be quantified. Results are used to improve the lithographic performance of the dual-wavelength CARL® [4,5] resist system presently used at Infineon Technologies.

Significant improvement in 157nm optical components lifetime is required for successful implementation of pilot and production scale 157nm lithography. To date, most of the 157nm optics lifetime data has been collected in controlled laboratory conditions by introducing predetermined concentrations of contaminants and monitoring degradation in terms of transmission loss. This publication compliments prior work by documenting field experience with the 157nm Exitech Microstepper currently in operation at International SEMATECH. Failure mechanisms of various optical components are presented and molecular contamination levels in purge gas, tool enclosure, and clean room are documented. Finally the impacts of contaminant deposition and degradation of components on imaging performance is discussed.