Elimination of Tungsten-voids in middle-of-line contacts for advanced planar CMOS AND FinFET technology

As dimension of middle-of-line contacts scale down, the Tungsten (W) gap-fill capability is critical, and we starts to see function failure in SRAM and logic circuit caused by W-voids. We had observed that formation of W-voids is related to the contact profile, nucleation/barrier on sidewall, and deposition methods. Furthermore, even those initially "good" W-plugs are formed, the subsequent process steps may damage the W-plug toward voids and they lead to high resistance and failures in logic circuit and SRAM. We analyzed mechanisms and illustrated solutions systematically with in-line detection method also discussed for technology development as well as manufacturing in paper.