This study investigates the metal pitch 18 (MP18) via critical dimension (CD) and overlay process window (PW) for a two-metal-layer Ru semi-damascene integration scheme with a fully self-aligned via (FSAV) approach. The via CD and overlay PW was experimentally assessed from electrical tests probing the Kelvin via resistance yield and via-to-line leakage yield under a changing via CD and via y-overlay. Results show that >80% yield can be obtained for a 26.3 +/−2.0 nm via litho CD and a +/−4 nm via y-overlay PW for FSAV semi-damascene.
