Lithography is a photographic process that is used to transfer the geometric patterns describing an integrated circuit to the silicon wafer. After a lithography step, chemical, etching, impurity deposition, or oxidation process steps are performed on the silicon wafer to further delineate the circuit structure. These sequential lithography and processing steps precisely form the three-dimensional electrical circuit on the silicon surface, thus producing the integrated circuits used in all types of electronic communications, displays, and signal processing equipment.