Lithographers have steadily reduced exposure wavelength and increased numerical aperture (NA) to maintain process window and simplicity. The G-line systems of the 1970s gave way to the I-line systems of the late 80s, and then to the deep ultraviolet (DUV) systems of today. This paper describes our characterization of a DUV lithography system for the manufacture of 16-Mb DRAM chips at 500-nm ground rules. The process consists of a positive-tone, aqueous-base developable photoresist with an overcoat for sensitivity control, and an anti- reflective coating (ARC) on selected levels. The exposure tools used are step-and-scan systems with a 0.36 NA and expose bandpass of 240 - 255 nm. Apply and develop processes are clustered with the expose tool to minimize defects, reduce cycle time, and eliminate process variables.

Date Published: 9 July 1992
PDF: 19 pages
Proc. SPIE 1671, Electron-Beam, X-Ray, and Ion-Beam Submicrometer Lithographies for Manufacturing II, (9 July 1992); doi: 10.1117/12.136040

Published in SPIE Proceedings Vol. 1671:
Electron-Beam, X-Ray, and Ion-Beam Submicrometer Lithographies for Manufacturing II
Martin C. Peckerar, Editor(s)