Submicron Al–Si–Cu filled via formation by a high‐temperature sputter deposition method employing Ti underlayers and via electrical properties were studied. It was found that degree of filling, via chain resistance, and variation of the via chain resistance depend on the Ti underlayer thickness. The via chain resistance and its variation with thick Ti underlayer (50–100 nm) are smaller than those with thin Ti underlayer (20 nm). This might be because of improvement in wettability of Al–Si–Cu films at via sidewall, which is caused by uniform interfacial reaction between the Ti underlayer and the Al–Si–Cu film. It was shown that Al films at the via holes consist of one or two single crystalline. With Ti underlayer thickness of 20 nm, electromigration resistance for Al–Si–Cu filled via chains with low resistance was a factor of about 20 times greater than that of Al unfilled vias by a conventional sputter deposition method. On the contrary, the filled via chains with high resistance failed at an initial stage during electromigration testing. Also, it was found that via resistance increase during electromigration is caused by the depletion of Al–Ti–Si compounds in the vicinity of the Al plug via interface.