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Proceedings Paper

Non-ARC solution to metal reflective notching: its evaluation and selection
Author(s): Stephen Jack Buffat
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Paper Abstract

Patterning photoresists on reflective topography such as aluminum is one of the more difficult problems in device manufacturing. Interference effects caused by reflected light from the substrate/photoresist interface and surface topography result in coupling of additional energy into the film. This leads to linewidth variation known as reflective notching which severely impacts process latitude and increases critical dimension variation. For many years, suppliers approached the problem by adding dyes that absorb in the actinic region to create a larger non-bleachable absorption. In recent years, strongly absorbing intermediate layers or ARC's, both organic and inorganic, have seen widespread implementation to control reflective notching. However, if a fab is not equipped to accommodate the required ARC process, the processing can be very time consuming, cumbersome and costly. This study was undertaken to determine if a non-ARC, i-line photoresist process could be developed to reduce or eliminate aluminum reflective notching and accompanying critical dimension variation. This study was designed to screen, identify, and characterize various resist chemistries. Based on the screening characterization, a final, cost effective resist chemistry without ARC was selected, fully characterized and transferred into production. The selected material is currently being used in a high volume 0.60 micrometers CMOS, 200 mm wafer manufacturing process.

Paper Details

Date Published: 7 July 1997
PDF: 15 pages
Proc. SPIE 3051, Optical Microlithography X, (7 July 1997); doi: 10.1117/12.276029
Show Author Affiliations
Stephen Jack Buffat, Zilog, Inc. (United States)

Published in SPIE Proceedings Vol. 3051:
Optical Microlithography X
Gene E. Fuller, Editor(s)

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