Physical-Model Guided Design on Transistor Test Structures for Extracting Metal Charging Design Rules

Physical-model guided design on transistor test structures aiming for extracting backend metal charging design rules is demonstrated for the first time. Based on experimental data from a six-metal-layer technology, the demonstration shows such design methodology to be feasible. The methodology enables adequate design for the test structures from which a complete set of metal charging design rules can be extracted for a given process technology. This paper concludes that a significant reduction in the number of the required test structures and accordingly a large saving for test chip layout space during process development can be realized with the new design methodology. The number of the design-rule-extraction test structures could be reduced by a half for a six-metal-layer technology and by 77% for a thirteen-metal-layer layer technology, with a minimum number as low as four per transistor type, gate oxide thickness, and gate protection option if such methodology is adopted. The advantage inherited in the new methodology is delineated.