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Proceedings Paper

Improvement of pattern collapse issue by additive-added D.I. water rinse process
Author(s): Keiichi Tanaka; Ryoichiro Naito; Tomohiro Kitada; Yukio Kiba; Yoshiaki Yamada; Masakazu Kobayashi; Hiroyuki Ichikawa
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Paper Abstract

Reduction of critical dimension in lithography technology is aggressively promoted. At the same time, further resist thickness reduction is being pursued to increase the resolution capabilities of resist. However, thin film has its limitation because of etch requirements etc. As that result, the promotion of reduction results in increasing the aspect ratio, which leads to pattern collapse. It is well known that at drying step in developing process the capillary effect operates the photoresist pattern. If the force of the capillary effect is greater than the aggregation force of the resist pattern, the pattern collapse is generated. And the key parameters of the capillary effect are the space width between patterns, the aspect ratio, the contact angle of the D.I water rinse and the surface tension of rinse solution. Among these parameters the surface tension of rinse solution can be controlled by us. On the other hand, we've already reported that the penetration of TMAH and D.I water into the resist plays an important role on the lithographic latitude. For example, when we use the resist which TMA ion can be easily diffuse into, D.I water and TMA ion which are penetrated in the resist decreases the aggregation force of resist pattern and causes the pattern collapse even by the weak force against resist pattern. These results indicate that the swelling of photoresist by TMA ion and water is very important factor for controlling the pattern collapse. Currently, two methods are mainly tried to reduce the surface tension of rinse solution: SCF (Super Critical Fluid) and addition of additive to D.I water rinse. We used the latter method this time, because this technique has retrofittability and not special tool. And in this evaluation, we found that the degree of suppressing pattern collapse depends on the additive chemistry or formulation. With consideration given to process factors such as above, we investigated what factors contribute to suppressing pattern collapse for each resist platform when using additive-added rinse solutions. This report describes the results of our examinations and discussions of the pattern collapse mechanism.

Paper Details

Date Published: 12 June 2003
PDF: 16 pages
Proc. SPIE 5039, Advances in Resist Technology and Processing XX, (12 June 2003); doi: 10.1117/12.485069
Show Author Affiliations
Keiichi Tanaka, Tokyo Electron Kyushu Ltd. (Japan)
Ryoichiro Naito, Tokyo Electron Kyushu Ltd. (Japan)
Tomohiro Kitada, Tokyo Electron FE Ltd. (Japan)
Yukio Kiba, Tokyo Electron Kyushu Ltd. (Japan)
Yoshiaki Yamada, Tokyo Electron Kyushu Ltd. (Japan)
Masakazu Kobayashi, Clariant Japan K.K. (Japan)
Hiroyuki Ichikawa, Clariant Japan K.K. (Japan)

Published in SPIE Proceedings Vol. 5039:
Advances in Resist Technology and Processing XX
Theodore H. Fedynyshyn, Editor(s)

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