COMPUTER AIDED METHOD OF CIRCUIT EXTRACTION

A method and apparatus for extracting circuit design information from a pre-existing semiconductor integrated circuit (IC) or at least a portion thereof is described. It includes imaging at least a portion of two or more physical layers of the pre-existing IC to obtain stored electronic images of the physical IC layers, converting the stored electronic images of the physical IC layers to a vector format data, horizontally and vertically aligning the vector format data of the electronic stored images of the physical IC layers, and providing a multi-layer display of the aligned vector format data. A net-list or schematic is generated from the multi-layer display of the vector format data. The net-list and/or schematic may be generated as a number of individual pages by providing a template of circuit elements and placing a circuit element over a portion of the display corresponding to the circuit element. The template of circuit elements may include transistors, logic gates or complex circuit blocks. The vector format data may be altered to correct errors in the images or manipulated to correct the alignment of the images. In addition, the schematic may be traced to the image of the physical IC layer.