Pattern collapse mitigation by controlling atmosphere during development process for semiconductor lithography

The negative pressure atmosphere during the development process was investigated to mitigate the photoresist pattern collapse which is one of the traditional issues in the lithography processes for every generation of photoresists; i-line, KrF, ArF, ArF immersion, and recently extreme ultraviolet. The pattern collapse is caused by the capillary force between resist patterns during rinsing and drying in the development process. The main factors of capillary force are the surface tension and the contact angle of rinsing liquid and also the pattern structure (line width, space width, and height). On the other hand, the capillary force is influenced by the atmosphere pressure. In this paper, we controlled the chamber pressure during the rinsing and drying processes for the pattern collapse mitigation. The minimum critical dimension without pattern collapse under the negative pressure was found to be smaller (approximately 10% improvement) than that obtained with atmosphere pressure.