Method for manufacturing a semiconductor device
A semiconductor device includes a semiconductor substrate, a copper-containing metal interconnect over the semiconductor substrate, and a copper-containing connection plug, and the metal interconnect includes metal elements other than copper, and a concentration of different metal elements in a connection portion between the metal interconnect and the connection plug is higher than a concentration of the different metal elements in a center portion of the metal interconnect, and higher than a concentration of different elements in upper face portion of the metal interconnect other than the connection portion.
1. A method for manufacturing a semiconductor device, comprising:
forming a first insulating film on a substrate;
forming a first interconnect trench in said first insulating film;
forming a first copper containing metal film in said first interconnect trench;
forming a second insulating film on said first copper containing metal film and said first insulating film;
forming a connection hole reaching an upper face of said first copper containing metal film, and a second interconnect trench located on said connection hole, in said second insulating film;
forming a barrier metal film within said connection hole and contacting said upper face of said first copper containing metal film;
removing a portion of said barrier metal film contacting said first copper containing metal film to expose a portion of said upper surface;
forming a seed metal film including a copper element and different metal elements so as to come into contact with the exposed upper face of said first copper containing metal film, on inner portions of said connection hole and said second interconnect trench;
forming a second copper containing metal film so as to come into contact with an upper face of said seed metal film, on inner portions of said connection hole and said second interconnect trench; and
carrying out heat treatment of said first copper containing metal film and said seed metal film, thereby distributing the different metal elements into the first copper containing metal film.
2. The method for manufacturing a semiconductor device according to claim 1 , wherein said forming said first copper containing metal film, comprises:
forming lower layer seed metal film including copper element and different metal elements in said first interconnect trench; and
forming said first copper containing metal film so as to come into contact with an upper face of said lower layer seed metal film, in said first interconnect trench, and
further comprises:
carrying out heat treatment of said first copper containing metal film and said lower layer seed metal film.
3. The method for manufacturing a semiconductor device according to claim 2 , wherein said forming said lower layer seed metal film comprises:
forming said lower layer seed metal film including not less than one kind of elements selected from a group composed of Sn, Al and Ti as said different metal elements.
4. The method for manufacturing a semiconductor device according to claim 1 , wherein said forming said seed metal film comprises:
forming said seed metal film including not less than one kind of elements selected from a group composed of Sn, Al and Ti as said different metal elements.
5. A method for manufacturing a semiconductor device, comprising:
forming a first insulating film on a substrate;
forming an first interconnect trench in said first insulating film;
forming a first copper containing metal film in said first interconnect trench;
forming a second insulating film on said first copper containing metal film and said first insulating film;
forming a connection hole reaching an upper face of said first copper containing metal film, and a second interconnect trench located on said connection hole, in said second insulating film;
forming a barrier metal film in said connection hole and said second interconnect trench, the barrier metal film contacting said first copper containing metal film;
removing said barrier metal film residing on a bottom of said connection hole in such a way as to expose a portion of said first copper containing metal film;
forming a seed metal film including a copper element and different metal elements so as to come into contact with the exposed portion of said upper face of said first copper containing metal film, on inner portions of said connection hole and said second interconnect trench;
forming a second copper containing metal film so as to come into contact with an upper face of said seed metal film, on inner portions of said connection hole and said second interconnect trench; and
carrying out heat treatment of said first copper containing metal film and said seed metal film, thereby distributing the different metal elements into the first copper containing metal film.
6. The method for manufacturing a semiconductor device according to claim 5 , wherein said forming a barrier metal film in said connection hole and said second interconnect trench, comprises:
forming the tantalum containing barrier metal film.