Rewritable Direct-Write Photomask for Microcircuit Litography

Advances in integrated circuit fabrication require large numbers of high resolution masks for lithographic purposes. State-of-the-art lithographic tools have showed good submicron resolution, but are generally made on chrome-coated glass. The associated chrome coating, writing, photoresist processing, and etching have produced enormous chemical waste for the IC industry.. Physical Optics Corporation proposes a high-energy-beam sensitive glass as the mask blank for mask fabrication. The mask's pattern can be written into a thin layer of an ion-exchanged glass medium by high energy beams, like E-beams, deep UV, or short wavelength laser beams (180-200 nm), with high resolution (~0.2 um). The writing can also be performed by longer wavelength beams (400 to 900 nm) on an E-beam pre-exposed mask blank using an erasure mode. Low cost mask writing and replication provide enormous advantages. Stability of the masks under actinic radiation is expected. Phase I will demonstrate the concept's feasibility, good resolution, and high optical density in the darkened areas. A cost effective mask making machine will also be designed. Phase II will produce a new generation mask machine, based on the high-energy-beam-sensitive glass technology.