<title>Novel architecture for high-speed dual-image generation of pattern data for phase-shifting reticle inspection</title>

Abstract

The pattern data representing ULSI photolithography layers continues to grow exponentially when viewed at the image plane. Data derivation, verification, conversion, and movement have resulted in significant logistical problems and reticle production bottlenecks even with current device densities and reticle manufacturing technologies. With the advent of phase shifting reticle manufacturing and even more dense ULSI devices, database image generation for reticle defect inspection becomes an even more serious issue. Examination of 64 MBit pattern characteristics show that total figure counts per layer approach 1 billion figures per layer. Phase shifting structures increase figure counts per layer to over 1 billion figures. Defect sensitivities of 0.40 micrometers for chrome defects and 0.30 micrometers for phase shift defects are required for 64 MBit reticle inspection. Single die inspection area exceeds 5000 mm2 and die pixel counts are over 1011 pixels. Current reticle inspection database image generation technology requires ten hours per inspection pass. Data load times exceed one hour and data conversion to the inspection format exceeds ten hours. Total reticle inspection time in the manufacturing environment may approach 40 hours. A novel pattern generator architecture allowing 64 MBit reticle inspection in one hour is proposed. The NPG architecture includes a new data format, an integrated data conversion package, and a high resolution, high speed image generator. NPG data conversion performance is analyzed and 782 million figure 64 MBit data conversions are performed in less than one minute. Resulting file sizes are one million bytes. The NPG data format is shown to allow increased edge placement resolution to support increased inspection sensitivity. A method for simultaneously generating chrome and phase shift images is presented.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.