New system for fast submicron laser direct writing

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. A SLM with 512x464 pixels has been developed and fabricated using a CMOS active matrix and a reflective, deformable viscoelastic layer on top. Using this modulator for image generation a demonstrator exposure tool for 0.6µm minimum feature size has been designed and set up including all the components necessary for the exposure of a complete lithography layer from VAD layout data. The demonstrator is shown to give good quality photoresist pattern on the wafer at a throughput of roughly one 4"-wafer per hour. Based on our experimental results we propose a tool with a throughput of nine 6"-wafers per hour and conclude that the new principle of operation has the potential of high performance optical direct writing lithography.