The automatic synthesis of planar fabrication process flows for surface micromachined devices

A method which automatically generates fabricating sequences for surface micromachined structures starting from a two dimensional geometrical description is presented. This method translates the device geometry into layers and a mathematical representation of layer order. It is shown that all possible process sequences are extracted from the layer order in terms of fundamental processing steps like deposition, lithography, and etching using topological sorting techniques. In general, the fabrication sequence is not unique. Hence, an optimal sequence is selected from the set using a cost function based upon a database of materials and processes. A synthesis program that implements the sequencing algorithm and optimization was developed. The output of the synthesizer is a complete optimal fabrication sequence in human-readable form.