A new high-resolution photomask inspection system for contamination detection

STARlight2+ TM (SL2+) is a new high-resolution contamination inspection system based upon the KLA-Tencor TerascanHR platform. Building upon the proven technology of STARlight TM (SL2), SL2+ uses transmitted and reflected images to detect potentially yield-limiting contamination defects on photomasks for wafer fabs and mask shops. It extends the contamination inspection capability to the 32nm logic/45nm Half Pitch (HP) technology nodes using the newly developed 72nm pixel image resolution as well as a significantly improved rendering model in the algorithm. In this paper, we present inspection results on a wide variety of photomasks, spanning the 32nm to 110nm technology nodes, in the recently concluded period of Alpha tests on the SL2+ system. The test results show that the sensitivity and the inspection capability of the new SL2+ system have been greatly improved. Such improvement enables wafer fabs and mask shops to inspect and qualify photomasks for 32nm node development and 45nm node production.