Patent ID: 7391115

Claim:
A semiconductor device equipped with an interconnection or a via plug, being formed by a damascene structure; which comprises the structure in which a barrier film made of only two layered films, each of said two layered films containing silicon, carbon and nitrogen and having different carbon concentrations, is disposed between said interconnection or said via plug and its overlying layer that is an insulating interlayer, wherein said barrier film comprises, on the side of said interconnection or said via plug, a low-carbon-concentration film with a small carbon concentration and, on the side of said insulating interlayer, a high-carbon-concentration film with a carbon concentration larger than that of said low-carbon-concentration film and wherein when, the infrared absorption spectrum for said barrier film, infrared absorption areas of infrared absorption bands having a peak in the vicinity of 810 cm-1 and having a peak in the vicinity of 1250 cm 1 are denoted by I1 and I2, respectively, a value of I2/I1 for said low-carbon-concentration film in said barrier film is approximately 0.004 to 0.0067, and a value of I2/I1 for said high-carbon-concentration film in said barrier film is approximately 0.0067 to 0.014.