MASK DEFECT INSPECTION METHOD BY DATABASE COMPARISON WITH 0.25-0.35 MU-M SENSITIVITY

Photomasks used in the fabrication of ultra-LSI (ULSI) circuits must b e inspected for defects. For 256 Mbit dynamic random access read write memory (DRAM), it is necessary to inspect defects as small as 0.15 mu m. Moreover, inspection of defects of phase-shift masks is becoming a n important task of an inspection system, This paper describes an auto mated mask inspection system (MC-100) based on die-to-database compari son, and a defect inspection method with 0.15 mu m sensitivity for edg e and pindot defects. System configuration and the defect inspection m ethod are discussed in detail, including the difficulties of defect de tection in an attenuated phase-shift mask.