New phase shifting mask with self-aligned phase shifters for a quarter micron photolithography

Akihiro Nitayama, Takashi Sato, Kohji Hashimoto, Fumiaki Shigemitsu, Makoto Nakase

Research output: Contribution to journalConference articlepeer-review

52 Citations (Scopus)


In order to markedly improve the resolution of photolithography without improving the resolution of exposure systems, the authors propose a simple and effective phase shifting mask technology. The mask has self-aligned phase shifters which do not require assistant patterns and or complicated design of the phase shifter patterns, which are essential to the conventional phase shifting mask. The mask with a phase shifter size of 0.5 μm reduces the width of photointensity to 60% of that without phase shifters, while keeping high contrasts. The authors have fabricated the phase shifting mask and obtained 0.2-μm line resist patterns with a high-contrast resist profile by a KrF excimer laser stepper with resolution capability of 0.4 μm. The proposed phase shifting mask method is extremely attractive for a future ULSI lithography tool in 256-Mb DRAM (dynamic RAM) and beyond.

Original languageEnglish
Pages (from-to)57-60
Number of pages4
JournalTechnical Digest - International Electron Devices Meeting
Publication statusPublished - 1989 Dec 1
Event1989 International Electron Devices Meeting - Technical Digest - Washington, DC, USA
Duration: 1989 Dec 31989 Dec 6

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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