US Patent 11488965 SRAM device and manufacturing method thereof

An SRAM memory device includes a substrate, a first transistor, a second transistor, a metal interconnect structure, and a capacitor. The metal interconnect structure is formed on the first and second transistors. The capacitor is disposed in the metal interconnect structure and coupled between the first transistor and the second transistor. The capacitor includes a lower metal layer, a first electrode layer, a dielectric layer, a second electrode layer, and an upper metal layer from bottom to top. The lower metal layer is coupled to a source node of the first transistor and a source node of the second transistor. The lower metal layer and an n-th metal layer in the metal interconnect structure are formed of a same material, wherein n≥1; the upper metal layer and an m-th metal layer in the metal interconnect structure are formed of a same material, wherein m≥n+1.