Implementation of new reticle inspection technology for progressive mask defect detection strategy in wafer fabs

Abstract

Progressive and haze defects continue to be the primary cause of mask degradation and mask re-clean due mainly to intensified density of photon energy involved with ArF exposure. To monitor and prevent haze in production, the methodology of direct reticle inspection has been widely implemented in wafer fabs to provide early warning of haze defects before they reach a critical level. With the continuous shrinkage of IC design rules for scaling devices, reticle inspection systems are increasingly challenged by aggressive OPC and high sensitivity requirements to detect printable defects. In this paper, two new reticle inspection technologies: STARlight2+^TM (SL2+) and Thin-line De-sense (TLD) on Die-to-Die (D2D) mode have been studied and evaluated on ArF production test reticles. The haze defect capture rate, defect residue modulation, and rendering on SL2+ mode have been compared with STARlight2 (SL2); the false defect count and usable sensitivity for D2D with TLD have been compared with D2D mode without TLD. The results of the two new technologies revealed significant improvement on sensitivity, inspectability.