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Proceedings Paper

Investigating positive DUV resist profile on TiN
Author(s): Qizhi He; William L. Krisa; Wei W. Lee; Wei-Yung Hsu; Hong Yang
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Paper Abstract

It is well known that chemically amplified positive tone DUV resists are sensitive to substrate contamination, manifesting themselves as a 'foot' on TiN substrates. Studies have proposed that there is an interaction between nitrogen used in the formation of the TiN and the chemically amplified resist. This reaction occurs when the acid generated in the resist is neutralized by nitrogen and hence a foot is formed. However, the 'foot' abnormality of DUV resist over TiN substrates has not been fully understood or eliminated. In this paper, we study the performance of 0.25 mm features using Shipley's UVIIHS resist on a TiN/metal layer. When UVIIHS was initially evaluated the primary problem was the presence of a 'foot' at the bottom of the resist line. Subsequent studies were conducted on the effects of TiN thickness and composition. The results show the TiN thickness has little effect on the 'foot' while the TiN composition has a profound effect. As the N content in the TiN film increases the size of the food decreases. The foot decreases significantly when a very low nitrogen concentration is used and eliminated completely when using a barrier layer of 100 Ang Ti. Our results also demonstrate that surface pre-treatment of TiN using oxygen plasma can result in good 0.25 mm resist profiles with no noticeable foot present. The results we obtained indicate that chemical and physical properties of the TiN surface play a critical role in DUV resist performance. Therefore multiple spectroscopies have been employed to characterize TiN films including Rutherford backscattering, x-ray photoelectron, and time of flight secondary ion mass. These analysis provide many insights into the mechanism of the resist 'foot' phenomenon.

Paper Details

Date Published: 7 July 1997
PDF: 9 pages
Proc. SPIE 3049, Advances in Resist Technology and Processing XIV, (7 July 1997); doi: 10.1117/12.275899
Show Author Affiliations
Qizhi He, Texas Instruments (United States)
William L. Krisa, Texas Instruments (United States)
Wei W. Lee, Texas Instruments (United States)
Wei-Yung Hsu, Texas Instruments (United States)
Hong Yang, Texas Instruments (United States)

Published in SPIE Proceedings Vol. 3049:
Advances in Resist Technology and Processing XIV
Regine G. Tarascon-Auriol, Editor(s)

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