SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE

摘要

PURPOSE: To optimize the structure of a barrier film in the connection part for connecting wires and to improve the electromigration characteristics. CONSTITUTION: After forming a wiring trench HM2 and a contact hole C2 in an interlayer insulating film TH2 formed on first-layer wiring M1 on a semiconductor substrate, a barrier film PM2a is formed in them in such a way that its film thickness increases from the center of the bottom of the contact hole C2 toward the sidewall over the entire periphery of the bottom of the contact hole C2. After forming copper films (PM2b and PM2c) on the barrier film PM2a, second-layer wiring M2 and a connection part (plug) P2 are formed by polishing through CMP method. As a result, since the geometrically shortest path of the current flowing from the second-layer wiring M2 to the first-layer wiring M1 via the connection part (plug) P2 does not coincide with the thinner part of the barrier film PM2a where the electrical resistance is a minimum, a current path can be dispersed and the concentration of electrons can be made to less likely to occur.