One of the main challenges in photomask cleaning is balancing particle removal efficiency (PRE) with pattern damage control. To overcome this challenge, a high frequency megasonic cleaning strategy is implemented. Apart from megasonic frequency and power, photomask surface conditioning also influences cleaning performance. With improved wettability, cleanliness is enhanced while pattern damage risk is simultaneously reduced. Therefore, a particle removal process based on higher megasonic frequencies, combined with proper surface pre-treatment, provides improved cleanliness without the unintended side effects of pattern damage, thus supporting the extension of megasonic cleaning technology into 10nm half pitch (hp) device node and beyond.

Date Published: 4 October 2016
PDF: 7 pages
Proc. SPIE 9985, Photomask Technology 2016, 998515 (4 October 2016); doi: 10.1117/12.2241143

Published in SPIE Proceedings Vol. 9985:
Photomask Technology 2016
Bryan S. Kasprowicz; Peter D. Buck, Editor(s)