Share Email Print

Proceedings Paper

Contamination control for processing DUV chemically amplified photoresists
Author(s): Joseph C. Vigil; Mark William Barrick; Tim H. Grafe
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

Chemically amplified DUV photoresists have a sensitivity to certain airborne chemical contaminants. Processing these resists requires control of the environment within the process tooling. This study explores the contamination threshold levels to meet minimum established lithography criteria as well as the effectiveness of the equipment in providing such an environment. A DUV lithography cluster consisting of a SVGL MICRASCAN-II linked to an SVG Series 90 track are the platform for this study. Both the stepper and track utilize Donaldson stacked carbon filters, each is sized to design air flow rate. Measurement and control of two (2) known contaminants, n-methyl2-pyrolidone (NMP) and ammonia (NH3), are investigated in the stepper chamber, the track chamber, and the surrounding environment. Gas chromatography (GC) and ion mobility spectrometry (IMS) are used to measure NMP and NH3 levels, respectively, and provide the basis for the data presented. Criteria for resist profile, critical dimension (CD) and post exposure delay (PED) in a single layer resist system i.e., without resist top-coat (RTC), were set such that contamination effects are of no consequence. Contaminant threshold levels to meet this lithography criteria have been determined. Data that underscores the trade-off between having a single purpose filter or a dual purpose filter design that removes both NMP, an organic, and NH3, an inorganic, are analyzed. The effectiveness (efficiency and life time) of this dual purpose filter in reducing the contaminants to low enough levels for maintaining lithography acuity, as established by the criteria, are summarized. A cost analysis highlighting the economic trade-off of using either RTC in a non-filtered environment or providing a conducive filtered environment for single layer resist processing are analyzed. Conclusions based upon data from ambient conditions, both inside and outside the lithography cluster and the performance of the equipment are made. Recommendations are made on what constitutes a `clean' environment and when the use of RTC may become necessary.

Paper Details

Date Published: 9 June 1995
PDF: 18 pages
Proc. SPIE 2438, Advances in Resist Technology and Processing XII, (9 June 1995); doi: 10.1117/12.210386
Show Author Affiliations
Joseph C. Vigil, Motorola (United States)
Mark William Barrick, Motorola (United States)
Tim H. Grafe, Donaldson Co. (United States)

Published in SPIE Proceedings Vol. 2438:
Advances in Resist Technology and Processing XII
Robert D. Allen, Editor(s)

© SPIE. Terms of Use
Back to Top
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?