Testing of Optical Materials for 193-nm Applications
Abstract
We present an assessment of bulk fused silica and calcium fluoride, and of antireflective coatings for 193-nm lithographic applications. In the course of extensive marathon studies we have accumulated 1 - 5 billion laser pulses on over 100 bulk material samples at fluences from 0.2 to 4 mJ/sq cm/pulse. The results show large variation in both initial and induced absorption of fused silica (up to 40x for comparable irradiation doses) and in densification of fused silica (almost an order of magnitude spread at the equivalent 10-year system lifetime). For antireflective coatings, there are samples that undergo no appreciable degradation when irradiated for > 1 billion pulses at 15 mJ/sq cm/pulse. However, initial losses in some coatings (up to 2%) may be unacceptably high for lithographic applications.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 23, 1998
- Accession Number
- ADA366551
Entities
People
- A. Grenville
- J. H. Sedlacek
- M. Rothschild
- R. S. Uttaro
- V. Liberman
Organizations
- Massachusetts Institute of Technology