A new algorithm for ESD protection device extraction based on subgraph isomorphism

An efficient device recognition algorithm is critical to ESD (electrostatic discharge) protection device extraction. In this paper, we propose a new algorithm based on a subgraph isomorphism, where subgraphs appearing multiple times within the same or different device model graphs are presented once only, thus reducing computational effort of detecting them in an input layout file. The mechanism to detect and reduce redundant devices is also presented. The algorithm is implemented in a new CAD tool, ESDExtractor, developed to extract ESD devices of arbitrary shapes. Examples are provided to demonstrate the application of ESDExtractor and efficiency of the new algorithm.