Improving COO on KLA-Tencor wafer fab reticle inspections by implementing pixel migration as new STARlight2+ capability

KLA-Tencor has introduced the new TeraFab reticle inspection systems for wafer fabs to address market demand for systems with high productivity and high sensitivity. The core inspection technology of the TeraFab systems is STARlight2+ (SL2+). STARlight is the industry accepted method for mask inspection in wafer fabs for reticle requalification. STARlight uses transmitted and reflected light images of a reticle to generate reference images of the reticle that are used to detect defects that have been added to the reticle while the reticle has was exposed or in storage. The improvements in reference generation in SL2+ relative to previous generations of STARlight is made possible, in part, by increases in computation resources for TeraFab systems. Improved modeling capability of SL2+ leads to increased usable sensitivity in dense geometries. Improved modeling capability also allows the user to optimize inspection cost of ownership (COO) if the maximum sensitivity of the TeraFab system is not required for a specific application. This paper describes an investigation of sensitivity versus throughput using SL2+ on multi-die production reticles with haze at the 65nm technology node. SL2+ data is also provided showing the feasibility of using larger inspection pixels (pixel migration) while retaining good sensitivity at the 45nm technology node.