Automatic generation of thin film process flows. I. Basic algorithms

This paper is the first in a series of two papers describing the algorithms used in the development of MISTIC (Michigan synthesis tools for integrated circuits). MISTIC is a planar device process compiler that generates process flows for thin film devices from schematics of their structure. This software uses a laboratory specific database of process recipes to produce process flows for a specific set of laboratory resources (furnaces, etchers, lithography equipment, etc.) and generates process statistics that help to choose the most suitable process flow in a comparative manner. The process compiler is augmented by several auxiliary modules: a device builder, process viewer, and database editor thus forming a self-contained process design environment. This paper concentrates on the algorithms used to construct process flows from schematic device representations. The compiler algorithms first extract a directed graph representation of the device organization stored in the form of a restricted square boolean matrix. This matrix is used to generate linear ordered lists of device layers which serve as footprints for the construction of process flows. Process flows are then constructed from these lists through a series of conversions, expansions, and insertions of process steps