Quarter Micron KrF Excimer Laser Lithography

Masaru SASAGO  Masayuki ENDO  Yoshiyuki TANI  Satoshi KOBAYASHI  Taichi KOIZUMI  Takahiro MATSUO  Kazuhiro YAMASHITA  Noboru NOMURA  

IEICE TRANSACTIONS on Electronics   Vol.E76-C   No.4   pp.582-587
Publication Date: 1993/04/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Sub-Half Micron Si Device and Process Technologies)
Category: Process Technology
lithography,  resist,  excimer laser,  anti-reflection,  

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This paper describes the potential of KrF excimer laser lithography for the development and production of 64 M and 256 Mbit DRAMs on the basis of our recent developed results. Quarter micron KrF excimer laser lithography has been developed. A new chemically amplified positive resist realizes high stability and process compatibility for 0.25 micron line and space patterns and 0.35 micron contact hole patterns. This developed resist is characterized as the increase of dissolution characteristics in exposed areas, and hence means the high resolution is obtained. A multiple interference effect was greatly reduced by using our over coat film or anti-reflective coating. This over coat film has no intermixing to the resist and it is simultaneously removed when the resist is developed. This anti-reflective coating has low etch selectivity to the resist, and hence the over coat film is etched away when etching the substrate. The two major results indicate that the KrF excimer laser lithography is promising for the development of 256 MDRAMs.