Vertically-aligned and conductive dummies in integrated circuit layers for capacitance reduction and bias independence and methods of manufacture

Abstract

Vertically-aligned and conductive dummies in integrated circuit (IC) layers reduce capacitance and bias independence. Dummies are islands of material in areas of metal and semiconductor IC layers without circuit features to avoid non-uniform polishing ('dishing'). Conductive diffusion layer dummies in a diffusion layer and conductive polysilicon dummies in a polysilicon layer above the diffusion layer reduce bias dependence and nonlinear circuit operation in the presence of an applied varying voltage. ICs with metal dummies vertically aligned in at least one metal layer above the polysilicon dummies and diffusion dummies reduce lateral coupling capacitance compared to ICs in which dummies are dispersed in a non-overlapping layout by a foundry layout tool. Avoiding lateral resistance-capacitance (RC) ladder networks created by dispersed dummies improves signal delays and power consumption in radio-frequency (RF) ICs.