The effect of drying rate on pattern collapse performance in thin film lithography

Wei-Ming Yeh; Richard A. Lawson; Laren M. Tolbert; Clifford L. Henderson

doi:10.1117/12.895114

15 April 2011 The effect of drying rate on pattern collapse performance in thin film lithography

Wei-Ming Yeh, Richard A. Lawson, Laren M. Tolbert, Clifford L. Henderson

Proceedings Volume 7972, Advances in Resist Materials and Processing Technology XXVIII; 79721Y (2011) https://doi.org/10.1117/12.895114
Event: SPIE Advanced Lithography, 2011, San Jose, California, United States

Abstract

As the semiconductor industry continues to push the limits of the lithography processes used to fabricate integrated circuits, pattern collapse during development and drying can have a substantial impact on process viability. This pattern collapse in general is caused by unbalanced capillary forces present during the drying step of the lithographic process. Significant research has focused on developing methods to reduce such capillary forces and improve the pattern collapse of photoresists. However, it appears that relatively little attention has been paid to other process dependent factors which may also significantly impact such collapse behavior. For example, another potential factor which may affect pattern collapse is the length of time during which the resist features are actually stressed during drying. As such, processes which result in different drying rates may be expected to yield different levels of pattern collapse. In this work, e-beam lithography was used to generate high resolution line-space pair arrays which contain different size spaces between a pair of adjacent lines in a model chemically amplified resist. Such line pairs present an excellent tool for studying pattern collapse and quantifying the level of stress required to cause collapse and failure of resist features. After development and rinse, such pattern collapse test structures were dried using a variety of different processes possessing a variety of different drying rates, and the impact of these different drying methods on pattern collapse was quantified. It was indeed found that drying rate has a dramatic impact on pattern collapse, with spin drying techniques performing better than most other techniques. However, it was discovered that such spin drying methods also yield a significant pattern orientation dependence of the degree of pattern collapse. Such behavior is explained in terms of additional mechanical forces caused by the centrifugal forces exerted during spin drying methods.

Citation Download Citation

Wei-Ming Yeh, Richard A. Lawson, Laren M. Tolbert, and Clifford L. Henderson "The effect of drying rate on pattern collapse performance in thin film lithography", Proc. SPIE 7972, Advances in Resist Materials and Processing Technology XXVIII, 79721Y (15 April 2011); https://doi.org/10.1117/12.895114

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