Semiconductor device and method for manufacturing same
View Patent ↗A technology for inhibiting the dielectric breakdown occurred in a semiconductor device is provided. A semiconductor device includes a semiconductor substrate (not shown), an interlayer insulating film 102 formed on the semiconductor substrate and a multiple-layered insulating film 140 provided on the interlayer insulating film 102 . The semiconductor device also includes an electric conductor that extends through the multiple-layered insulating film 140 and includes a Cu film 120 and a barrier metal film 118 . The barrier metal film 118 is covers side surfaces and a bottom surface of the Cu film 120 . An insulating film 116 is disposed between the multiple-layered insulating film 140 and the electric conductor (i.e., Cu film 120 and barrier metal film 118 ).
1. A method for manufacturing a semiconductor device, comprising:
forming on an upper portion of the semiconductor substrate a multiple-layered insulating film that includes a first insulating layer, a second insulating layer and a third insulating layer, said second insulating layer being provided on said first insulating layer and having lower dielectric constant than the dielectric constant of said first insulating layer, said third insulating layer being provided on said second insulating layer and having higher dielectric constant than the dielectric constant of said second insulating layer;
forming an insulating film by forming an opening, which extends through said multiple-layered insulating film, and covering a portion of a side surface of said opening in vicinity of an interface between said first insulating layer and said second insulating layer and a portion of a side surface of said opening in vicinity of an interface between said second insulating layer and said third insulating layer; and
forming an electric conductor containing copper or copper alloy on a portion inside of said insulating film within said opening so as to extend through said multiple-layered insulating film.
2. The method according to claim 1 , wherein said forming said insulating film includes providing an adhesion of a portion of said first insulating layer onto a side surface of said opening when said opening is formed, by sputter etching a portion of said first insulating layer.
3. The method according to claim 2 , wherein said forming said insulating film includes: forming a bottom surface of said opening being included within said first insulating layer by sputter etching a portion of said first insulating layer; and forming said opening extending through said multiple-layered insulating film by partially removing the first insulating layer right under the bottom surface of said opening.
4. The method according to claim 1 , wherein said forming said insulating film includes providing an adhesion of a portion of said first insulating layer onto a side surface of said opening when said opening is formed by conducting an anisotropic dry etching of a portion of said first insulating layer.
5. The method according to claim 4 , wherein said providing the adhesion of a portion of said first insulating layer includes conducting an anisotropic dry etching by employing an etchant gas containing fluorocarbon gas and nitrogen gas or hydrogen gas.
6. The method according to claim 1 , wherein said forming said electric conductor includes forming a barrier metal film on a portion inside of said insulating film within said opening,
and forming a layer of copper or copper alloy on a portion inside of said barrier metal film within said opening.
7. The method according to claim 1 , wherein the inside of said insulating film is formed to be a forwardly tapered shape.