As the number of masks per wafer product set is increasing and low k1 lithography requires tight mask specifications, the patterning process below sub 20nm tech. node for critical layers will be much more expensive compared with previous tech. generations. Besides, the improved resolution and the zero defect level are necessary to meet tighter specifications on a mask and these resulted in the increased the blank mask price as well as the mask fabrication cost. Unfortunately, in spite of expensive price of blank masks, the certain number of defects on the blank mask is transformed into the mask defects and its ratio is increased. But using high quality blank mask is not a good idea to avoid defects on the blank mask because the price of a blank mask is proportional to specifications related to defect level. Furthermore, particular defects generated from the specific process during manufacturing a blank mask are detected as a smaller defect than real size by blank inspection tools because of its physical properties. As a result, it is almost impossible to prevent defects caused by blank masks during the mask manufacturing. In this paper, blank defect types which is evolved into mask defects and its unique characteristics are observed. Also, the repair issues are reviewed such as the pattern damage according to the defect types and the repair solution is suggested to satisfy the AIMS (Arial Image Measurement System) specification using a nanomachining tool.

Date Published: 16 September 2014
PDF: 8 pages
Proc. SPIE 9235, Photomask Technology 2014, 92350G (16 September 2014); doi: 10.1117/12.2066278

Published in SPIE Proceedings Vol. 9235:
Photomask Technology 2014
Paul W. Ackmann; Naoya Hayashi, Editor(s)