New system for fast submicron laser direct writing.

ABSTRACT We report on a new system for submicron lithography by fast laser direct writing, where a programmable phase modulating spatial light modulator (SLM) is imaged onto the wafer using flash on the fly exposure with an excimer laser light source. This new principle for maskiess optical lithography has been investigated for the first time. A SLM with 5 1 2x464 pixels has been developed and fabricated using a CMOS active mairix and a reflective, deformable viscoelastic layer on top. Using this light modulator for image generation a demonstrator exposure tool for O.6pm minimum feature size has been designed and set up including all the components necessary for the exposure of a complete lithographic layer from CAD layout data. The demonstrator is shown togive good quality photoresist pattern on the wafer at a throughput of roughly one 4"-wafer per hour. Based on ourexperimental results we propose a tool with a throughput of nine 6"-wafers per hour and conclude that the newprinciple of operation has the potential of high performance optical direct writing lithography.Keywords: laser direct writing, optical lithography, spatial ligrit modulator, deformable viscoelastic layer,exposure on the fly, excimer laser, DUV lithography