Middle of line dielectric layer engineering for via void prevention
Embodiments of the present disclosure are provide a method for fabricating a semiconductor device with fewer via voids (e.g., gaps between a dielectric layer and a metal fill of the semiconductor device). One such technique involves forming a dielectric layer, wherein at least a portion of the dielectric layer comprises a nonstoichiometric compound; forming one or more openings in the dielectric layer; filling the one or more openings with a metal, wherein the metal is disposed on a surface of each of the one or more openings; and exposing the dielectric layer and metal disposed in the openings to an oxidizing atmosphere, wherein exposing the dielectric layer and metal in the openings causes oxidation of the nonstoichiometric compound.
1 . A method for fabricating a semiconductor device, comprising:
depositing a stoichiometric film;
forming one or more openings in the stoichiometric film;
depositing a liner in the one or more openings, the liner comprising a nonstoichiometric compound, wherein the stoichiometric film and the liner form a dielectric layer;
filling the one or more openings with a metal, wherein the metal is disposed on a surface of each of the one or more openings; and
exposing the dielectric layer and the metal disposed in the one or more openings to an oxidizing atmosphere, wherein exposing the dielectric layer and the metal causes oxidation of the nonstoichiometric compound.
2 . The method of claim 1 , wherein the nonstoichiometric compound of the dielectric layer comprises a silicon-rich silicon oxide.
3 . The method of claim 1 , wherein the exposing the dielectric layer and the metal disposed in the one or more openings to an oxidizing atmosphere comprises annealing the nonstoichiometric compound in a low-temperature oxidizing ambient.
4 . The method of claim 1 , wherein the exposing the dielectric layer and the metal disposed in the one or more openings to an oxidizing atmosphere causes the dielectric layer at the surface of each of the one or more openings to grow.
5 . The method of claim 1 , wherein the exposing the dielectric layer and the metal disposed in the one or more openings to an oxidizing atmosphere causes the dielectric layer at the surface of each of the one or more openings to expand.
6 . The method of claim 1 , wherein
the filling the one or more openings with the metal further comprises forming a layer of the metal on a surface of the dielectric layer, and
the method further comprises:
removing the layer of the metal from the surface of the dielectric layer before exposing the dielectric layer and the metal disposed in the one or more openings to an oxidizing atmosphere.
7 . A method for fabricating a semiconductor device, comprising:
exposing a patterned dielectric layer disposed on a substrate to an oxidizing atmosphere, wherein:
the patterned dielectric layer comprises a first dielectric layer having openings, the first dielectric layer comprising:
a stoichiometric film in which the openings are formed; and
a liner in one or more of the openings, the liner comprising a nonstoichiometric compound,
each of the openings comprises a metal layer that is disposed on a surface of the opening,
the first dielectric layer comprises the nonstoichiometric compound, and
exposing the patterned dielectric layer to an oxidizing atmosphere causes oxidation of the nonstoichiometric compound at the surfaces of the openings.
8 . The method of claim 7 , wherein the nonstoichiometric compound of the first dielectric layer comprises a silicon-rich silicon oxide.
9 . The method of claim 7 , wherein the exposing the patterned dielectric layer to an oxidizing atmosphere comprises annealing the nonstoichiometric compound in a low-temperature oxidizing ambient.
10 . The method of claim 7 , wherein the exposing the patterned dielectric layer to an oxidizing atmosphere causes the dielectric layer at the surface of one or more of the openings to grow.
11 . The method of claim 7 , wherein the exposing the patterned dielectric layer to an oxidizing atmosphere causes the dielectric layer at the surface of one or more of the openings to expand.