Cap-metal of the lower metal can be partially etched at shallow via contacts in actual LSI devices. Influence of the cap-metal which partially remains in via contacts on via electromigration (EM) was investigated in cases where the cap-metal was WSi and TiN/Ti. The EM lifetime of via contacts where cap-metal remains is longer than that of via contacts where cap-metal is partially etched when using WSi cap-metal. However, the EM lifetime of via contacts where cap-metal is etched partially is longer than that of via contacts where cap-metal remains when using the TiN/Ti cap-metal. These mechanisms are discussed. Furthermore, EM characteristics of via contacts where aluminum and aluminum are connected directly are reinvestigated and also discussed.