Pushed-rule bit cells with new functionality

Abstract

A memory bit cell suitable for use in semiconductor integrated circuits that utilizes pushed design rules and layout geometries optimized by a semiconductor foundry for standard memory bit cells and edge-cell structures that provides a different functionality from that provided by the foundry standard bit cell. This different functionality is achieved by interconnecting the elements of one or a plurality of standard foundry bit cells and edge cells to implement a different circuit with different operation from the original bit cells and edge cells. The positioning and interconnection of the standard bit cells and edge cells are implemented in a manner so as to maintain the same periodic geometric proximity effects to the maximum degree possible. A preferred embodiment of this invention is to interconnect two standard foundry six-transistor SRAM bit cells and two edge cells to create a Ternary Content Addressable Memory bit cell with mask and compare functionality in addition to bit storage functionality.