HIGH-THROUGHPUT OPTICAL DIRECT WRITE LITHOGRAPHY

This article describes a new system for submicron lithography by fast laser direct writing, where a programmable phase-modulating spatial li ght modulator (SLM) is imaged onto the wafer using flash-on-the-fly-ex posure by an excimer laser. A 512 x 464 pixel SLM has been developed a nd fabricated using a CMOS active matrix with a reflective, deformable viscoelastic reflective layer. A demonstration exposure tool for 0.6- mu m minimum feature size performs all the functions necessary for exp osure of a complete lithographic layer from GDSII CAD layout data. The initial prototype gives good quality 0.6-mu m photoresist patterns. A prototype with an increased throughput of several 150-mm wafers/hr is being designed.