Parameter extraction for 157nm photoresists

The design of 157nm photoresist is a daunting task since air, water, and most organic compounds are opaque at this wavelength. Spectroscopic studies' led to the observation that fluorinated hydrocarbons improve the transparency of 157nm resist materials rather dramatically. These fluorinated resists have quickly become the prominent material platform for a variety of research activities. Regardless of wavelength, developing a practical photoresist material is always challenging; the added difficulties associated with 157nm radiation complicates the overall design problem and severely limits the choice of material classes to work with. This paper will discuss our 157nm simulation and parameter extraction efforts that have been completed over the past few months at International SEMATECH. During the past year we have developed the methodologies and practical test methods that are needed to study the lithographic behavior of 157nm. resist systems. Our work is based on procedures in the open literature and augmented by internal research.