Automating mask shop data preparation

Abstract

In the late 1970's and early 1980's it became apparent that soft-contact and projection aligners were not going to produce acceptable yields for the one- to three-micron technologies that would be demanded by the mid 1980's. Projection step-and-repeat systems appeared to be the preferred method of wafer imaging, with non-optically generated (e-beam) reticles providing the best masks. Compounded by denser, more complicated circuit designs, this new wave of technology demanded new philosophies for data preparation. With mean-time-between-failure on optical pattern generators shorter than the time it would take to generate some of these new masks, it also became obvious that pattern generators were not going to handle any of the newer technologies. Mask shops were soon faced with the problems associated with multiple tooling techniques, the different data preparation techniques required to support each, as well as the responsibility of maintaining the existing tooling on the older systems.