Reticle Quality Management System
The SL3 STARlight (simultaneous transmitted and reflected light) contamination inspection system and the Model 91 reticle inspection data management server are key contributors to KLA-Tencor's reticle quality management (RQM) technology. A comprehensive RQM solution can provide consistent photomask contamination inspection for the life of the photomask - from the time it leaves the photomask manufacturer through multiple uses in the fab lithography process. Regularly scheduled photomask inspection helps prevent mask degradation that can result in either wafer yield excursions or decreased yield value from lower device performance.
The SL3 is designed to perform final reticle inspections prior to shipment from the mask manufacturer, as well as mask inspections at wafer fab incoming quality control (IQC) and photolithography process requalification. The Model 91, in addition to storing, displaying and printing photomask inspection results, provides a vital connectivity link between reticle inspection and wafer yield. Both systems have been specifically designed for the wafer fab environment, with smaller configurations, increased automation and integrated process analysis capabilities.
The SL3 uses a single laser light source to illuminate the photomask and then capture the reflected and transmitted light with sensors. A loss in light intensity indicates a defect. The system inspects the mask for contamination, such as particulate matter, transmission errors and electrostatic discharge (ESD) damage, on its chrome surface. Its unpatterned reticle surface analysis (URSA) option enables the system to inspect all reticle surfaces including the pellicle and backside of the reticle. This tool, the successor to the SL300; delivers improved ease-of-use, lower operator time and a reduced system footprint (48 sq. ft smaller). An upgrade path for the established base of SL300s is currently available.
The Model 91 is the information management component of KLA-Tencor's RQM technology. In addition to storing, viewing and printing reticle inspection results, it carries out basic analysis functions, such as sensitivity analysis and process monitoring, and is designed to host other analysis applications, such as wafer analysis software and defect printability evaluations. Additional functionality under development will provide the ability to export reticle inspection results that can be read by wafer analysis software.
KLA-Tencor Corporation, 160 Rio Robles, San Jose, CA 95134. Tel: 408-875-4200; Fax: 408/571-3030.