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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.

The design of 193 nm photoresists with improved reactive ion etch (RIE) resistance has been a longstanding aim of both industrial and academic research and development programs. A variety of correlations between photoresist polymer structure and etch resistance have been developed,'3 however, the universality of these approaches, and in particular, the practicality of making comparisons across specific polymer families and specific RIE processes has recently been called in to question.4 In order to examine structure:RIE correlations in more detail, we have developed a new model based on the incremental structural parameter (ISP.)This model makes use of a molecular fragment-based definition of polymer structure which incorporates and extends aspects of previous parameters such as the Ohnishi and Ring parameters. An initial study revealed that this model allowed quantitative correlations between polymer families and across etch processes to be made.Continuing studies which examine the use of the ISP model in integrating 193 nm photoresists in prototype production processes will be described. Various polymer families used in deep-UV and 193 nm photoresists including methacrylates, alternating copolymers, styrenes, and cyclic olefins will be compared. We will present a more detailed description of the ISP model and of the follow-on 'new' ISP method which has been developed based on insights gained from the original ISP model, and make extended comparisons between the two ISP models.

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