The recent trend towards the shrinkage of semiconductor devices is sparking the miniaturization of photomask patterns. In turn, this has resulted in a demand for photomask cleaning technology that can eliminate contamination without causing damage, such as mask pattern collapsing and degradation of photomask optical properties. A two-fluid cleaning technology that can remove contamination without causing pattern collapsing has been gaining attention as a recent physical cleaning technology. It is now known that the advanced technology photomask cleaning is possible by controlling the diameter and the flow velocity of the liquid droplets discharged from the nozzle with two-fluid cleaning. However, it becomes impossible to explain damage only by the diameter of liquid droplets and flow velocity. In order to achieve a further improvement of the two-fluid cleaning technology, it is necessary to understand the mechanism of the damage accurately. We pay attention the study on a new parameter of damage and particle removal. The new parameter is liquid film thickness. We can rigorously describe the relation between damage and particle removal in terms of liquid droplet diameter, flow velocity and liquid film thickness by this study.

Date Published: 26 May 2010
PDF: 9 pages
Proc. SPIE 7748, Photomask and Next-Generation Lithography Mask Technology XVII, 77480Z (26 May 2010); doi: 10.1117/12.867980

Published in SPIE Proceedings Vol. 7748:
Photomask and Next-Generation Lithography Mask Technology XVII
Kunihiro Hosono, Editor(s)