Resistive extraction of polysilicon gate linewidth

The polysilicon gate linewidth manufacturing control strategy typically includes an electrical resistance measurement to extract the gate dimension. The extraction method usually assumes that wide (reference) and narrow (gate dimension) resistors have the same absolute sheet resistance. However, upon deeper examination, we found that this assumption is frequently invalid, submicron resistors do not necessarily have the same sheet resistance as wide resistors. Moreover, N-type and P-type narrow resistors exhibit quite divergent behaviors.