Semiconductor device having an interconnect structure and a reinforcing insulating film

A semiconductor device, comprising:

• an first interconnect layer including a plurality of interconnects;
• a first cap metal film provided to contact an upper portion of said interconnect and covering the upper portion of said interconnect;
• a conductive via provided on an upper portion of said first cap metal film and connected to said interconnect;
• a first contiguously integrated insulating film provided from a side wall of said interconnect to a side wall of said conductive via and formed so as to cover the side wall of said interconnect, the upper portion of said interconnect, and the side wall of said conductive via, and an upper portion of said first contiguously integrated insulating film is denser than a lower portion of said first contiguously integrated insulating film;
• a first reinforcing insulating film disposed under said first contiguously integrated insulating film and contact with a lower portion of the side wall of said interconnect, a thickness of said first reinforcing insulating film being substantially uniform and said first reinforcing insulating film having greater film density than said first contiguously integrated insulating film,
• a second interconnect layer made of a copper-containing metal and provided on an upper portion of said conductive via to be connected to said conductive via;
• and
• a second reinforcing insulating film disposed as an upper layer of said first contiguously integrated insulating film so as to contact a lower portion of a sidewall of said second interconnect with greater film density than said first contiguously integrated insulating film, a thickness of said second reinforcing insulating film being substantially uniform and said second reinforcing insulating film having greater film density than said first contiguously integrated insulating film.