A Metal Gate Height Variation Control Method by the Metal Gate Etch at the FinFET Technology

The metal gate (MG) height composed of complicated work function metal (WFM) films is crucial to the device and yield performance at the FinFET Technology. The parasitic capacitance between MGs and conductors gets increased with the increasing MG height while an disproportional relation is found between the channel resistance and MG height. In this paper, temperature sensitivities of various MG films were investigated and a new MG structure was proposed for the Hydra implementation. The MG height variation across the 300mm wafer was controlled with a Hydra based MG etching on the proposed sidewall WFM chamfered structure. The final MG height uniformity was improved 24%. Current work could be extended to the control of the wafer-to-wafer MG height variation.