METHOD FOR FORMING INSULATOR FILM ON METAL FILM
According to one embodiment, forming a metal film on an underlying layer, and depositing an oxide film on the metal film using plasma of a mixed gas induced above the metal film. The mixed gas includes a gaseous material source, a gaseous oxidant, and a gaseous reductant.
1 . A film formation method comprising:
forming a metal film on an underlying layer; and
depositing an oxide film on the metal film using plasma of a mixed gas induced above the metal film, the mixed gas including a gaseous material source, a gaseous oxidant, and a gaseous reductant.
2 . The method according to claim 1 , wherein
the gaseous material source includes one of monosilane, disilane, tetraethoxysilane and tetramethoxysilane; and the oxide film is a silicon oxide film.
3 . The method according to claim 1 , wherein
the gaseous oxidant includes one of nitrous oxide and nitrogen oxide.
4 . The method according to claim 1 , wherein
the gaseous reductant includes at least one selected from hydrogen, nitrogen monoxide, and carbon monoxide.
5 . The method according to claim 1 , wherein
the gaseous reductant is supplied in an initial period of a deposition time of the oxide film, and not supplied in a remaining period.
6 . The method according to claim 1 , wherein
a plurality of metal films stacked via the oxide film are formed on the underlying layer by repeating the steps of forming the metal film and depositing the oxide film.
7 . The method according to claim 1 , further comprising:
treating a surface of the metal film using inert gas plasma before depositing the oxide film.
8 . The method according to claim 7 , further comprising:
treating the surface of the metal film using reductive gas plasma after the treatment using the inert gas plasma.
9 . The method according to claim 1 , further comprising:
treating a surface of the metal film using reductive gas plasma before depositing the metal film; and
treating the surface of the metal film using inert gas plasma after the treatment using the reductive gas plasma.
10 . The method according to claim 1 , further comprising:
treating a surface of the metal film before depositing the oxide film, using plasma of a mixed gas that includes an inert gas and a gaseous reductant.
11 . The method according to claim 1 , wherein
the metal film is one of a tungsten film and a molybdenum film.
12 . The method according to claim 1 , wherein
plasma is induced between a first electrode and a second electrode, wherein a wafer including the underlying layer is placed on the first electrode, and a second electrode having a plurality of holes through which the mixed gas is supplied; and
the oxide film is deposited under a prescribed bias applied between the first electrode and the second electrode.
13 . The method according to claim 1 , wherein the metal film and the oxide film are continuously deposited in a same deposition chamber.
14 . A method for manufacturing a semiconductor device comprising:
forming a plurality of metal films stacked on an underlying layer comprising:
forming an initial metal film on the underlying layer;
depositing an oxide film on the initial metal film using plasma of a mixed gas induced above the initial metal film, the mixed gas including a gaseous material source, a gaseous oxidant, and a gaseous reductant; and
repeating steps of forming a metal film on the oxide film and depositing an oxide film on the metal film using plasma of the mixed gas;
forming a memory hole piercing through the plurality of metal films in the stacking direction;
forming a memory film on an inner surface of the memory hole; and
forming a semiconductor layer on the memory film inside the memory hole.
15 . The method according to claim 14 , wherein
the gaseous material source includes one of monosilane, disilane, tetraethoxysilane and tetramethoxysilane; and the oxide film is a silicon oxide film.
16 . The method according to claim 14 , wherein
each of the plurality of metal films is one of a tungsten film and a molybdenum film.
17 . The method according to claim 14 , wherein
each of the plurality of metal films has a stacked structure that includes a barrier metal and a metal having higher conductivity than a conductivity of the barrier metal.
18 . The method according to claim 14 , wherein
each of the plurality of metal films and the oxide film are continuously deposited in a same deposition chamber.