Paper
26 March 1993 Real and imaginary phase-shifting masks
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Abstract
Use of the phase-shifting mask in lithography allows substantial improvement of the resolution of commercial steppers for periodic circuit patterns, and, in certain cases, features smaller than 200 nm can be fabricated using i-line steppers ((lambda) equals 365 nm). There has therefore been much interest in developing this technology in recent years. In this paper, we examine and compare several approaches to evaluating mask designs for terminated periodic features, narrow gate lines, and contact holes, and compare the simulations with the actual results obtained when one attempts to use these designs in practice. Although we have found atomic force microscopy (AFM) to be a key tool for metrology, we conclude that there is a vital need for mask simulation, fabrication, inspection, and repair techniques to be developed further before these `imaginary' masks can be useful in the real world.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Franklin M. Schellenberg and David Levenson "Real and imaginary phase-shifting masks", Proc. SPIE 1809, 12th Annual BACUS Symposium on Photomask Technology and Management, (26 March 1993); https://doi.org/10.1117/12.142145
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CITATIONS
Cited by 7 scholarly publications and 4 patents.
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KEYWORDS
Photomasks

Phase shifts

Fourier transforms

Lithography

Computer aided design

Photoresist materials

Solids

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