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At 32nm technology node and beyond, the number of defect to be repaired is increased because pattern size is shrunk
and the detecting ability of inspection system higher than before. In repair system, mask surface is exposed to the
various contaminations such as contamination from vacuum chamber wall, reaction gas for repair etc. Although
contaminations deposited on mask surface are removed by followed cleaning process, it makes reflectance change on
scan area detected by high resolution inspection system. This reflectance change on scan area in repair system detected
during inspection is big burden for mask making because the number of scan area requires more time to confirm and
need AIMS simulation if there is any issue on the area. Most of all, it is hard to find where the exact repaired pattern is
and verify whether there are no problems because inspection system does not detect exact repaired pattern but detect all
scan area. Especially, this phenomenon is more observed to MoSi absorber of OMOG mask.
In this paper, we demonstrate the findings of contamination source and the root cause of contamination using surface
analyzing methods, ToF-SIMS(Time of Flight-SIMS) and AFM(Atomic Force Microscope). In addition, preventive
strategy to minimize and remove reflectance change issue in repair system will be discussed.
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