Preliminary results for photomask haze mitigation in a fab environment
Abstract
A persistent industry problem impacting photomask yield and costs has been haze formation. The haze nucleation and growth phenomenon on critical photomask surfaces has periodically gained attention as it has significantly impacted wafer printability for different technology nodes over the years. A number of process solutions have been promoted in the semiconductor industry which has been shown to suppress or minimize the propensity for haze formation, but none of these technologies can stop every instance of haze. Thus some capability will always be needed to remove haze on photomasks with their final pellicles mounted both at the manufacture and long term maintenance stages of a mask's lifetime. A novel technology is reviewed here which uses a dry (no chemical effluents) removal system to sweep the entire printable region of a pelliclized photomask to eliminate all removable haze regardless of the mask substrate materials or the presence of critical patterns. An operational process technique for this system and performance in removal is shown for haze located on the mask pattern surface. Finally, preliminary data from tool acceptance and preliminary use in a production environment will also be reviewed.
- Publication:
-
Metrology, Inspection, and Process Control for Microlithography XXIV
- Pub Date:
- March 2010
- DOI:
- 10.1117/12.848283
- Bibcode:
- 2010SPIE.7638E..17K