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Proceedings Paper

New imaging technique for 64M-DRAM
Author(s): Naomasa Shiraishi; Shigeru Hirukawa; Yuichiro Takeuchi; Nobutaka Magome
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Paper Abstract

We have established a new photolithographic technique called SHRINC ( Super High Resolution by I I tumi-Nation Control ) which is based on an innovative illumination system. SHRINC improves the resolution and depth-of-focus ( DOF ) by optimum arrangement of the illumination system in respect of the angle of the Ist-order of diffraction generated by the reticle pitch. The capabilities of SHRINC have been studied by computer simulation. Results from phase shift, annular illumination, and conventional illumination are compared with those of SHRINC. The results show that using SHRINC with 0.35? m line and space patterns, the DOF, defined as the distance over which the aerial image contrast exceeds 60%, is 2. 5x larger than that obtained with conventional illumination, and almost the same as that with phase shift techniques. In our experiments we have obtained a critical resolution of 0. 275 ? m and more than 2.8 ? m DOF with 0.35? m L/S patterns, using an i-line stepper and SHRINC illumination. Moreover SHRINC is effective not only for simple line and space patterns, but also for complicated patterns with 0.30 or 0.35?m design rules, such as memory cell patterns or peripheral circuit patterns in the DRAM. From these results we conclude that i-line steppers with SHRINC will make possible mass production of 64M-DRAMs with single layer resist.

Paper Details

Date Published: 1 June 1992
PDF: 12 pages
Proc. SPIE 1674, Optical/Laser Microlithography V, (1 June 1992); doi: 10.1117/12.130364
Show Author Affiliations
Naomasa Shiraishi, Nikon Corp. (Japan)
Shigeru Hirukawa, Nikon Corp. (Japan)
Yuichiro Takeuchi, Nikon Corp. (Japan)
Nobutaka Magome, Nikon Corp. (Japan)

Published in SPIE Proceedings Vol. 1674:
Optical/Laser Microlithography V
John D. Cuthbert, Editor(s)

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