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Product Briefing Outline: KLA-Tencor has launched the ‘TeraScanHR' system, a production-capable 45nm-generation photomask inspection system. The TeraScanHR system features higher imaging resolution and precise database modeling for high defect detection sensitivity and low false detections in both die-to-die and die-to-database modes.  The system also has higher-speed image processing for improved productivity, according to the company. KLA-Tencor has already shipped multiple TeraScanHR systems, and has received orders from all leading-edge merchant photomask suppliers, as well as logic, memory and foundry IC manufacturers for 45nm pre-production and 32nm development and demonstration.

Problem: The current generation of reticle defect inspection systems has inadequate optical imaging resolution and inadequate database modeling for the 45nm and 32nm nodes considering the small features and defects.  This inadequacy typically results in high false detections and insufficient sensitivity to meet the needed quality requirements. Transmitted illumination mode (T) has been traditionally used for inspection; however, reflected illumination (R) has become a requirement at 65nm and beyond to ensure that all defects are detected with the best sensitivity possible. For example, reflected light mode can better detect some defect types, such as pinholes, clear extensions, clear bridges and contamination. Reflected illumination mode improves performance for clear SRAF designs which are becoming increasingly common for the advanced mask generations.
 
Solution: The TeraScanHR features a new image acquisition system with high NA, ultra-low aberration optics, a new high-precision autofocus capability, and an improved stage with lower vibration. It uses a new optical imaging sub-systems and a new 72nm pixel to resolve small OPC structures, small lines and spaces, and small defects. The autofocus capability is enhanced with a separate beam and a pre-mapping technique to maintain proper focus on the photomask surface while compensating for photomask flatness, bow, tilt, vibration, thermal effects, etc.  The autofocus system also enables the tool to maintain proper focus on complex photomasks with significant topology, such as etched quartz and tri-tone mask types. In addition, new database modeling algorithms significantly improve the handling of complex OPC shapes, which provides higher defect sensitivity and a lower rate of nuisance and false detections, the company claims. While the T+R mode was available on prior-generation systems, the TeraScanHR's new supercomputer offers much faster T+R inspection.

Applications: Reticle inspection for binary (COG), 6% EPSM, and dark field alternating PSM reticles for 65nm and 45nm nodes.  

Platform: The TeraScanHR system can be configured into many different models to best match the inspection needs and economics of each user.  Different models offer a range of features, including various mode, sensitivity, and speed configurations. Field upgrades are available to add capability as needs change.  

Availability: March 2007 onwards.