Method for selectively oxidizing a silicon/metal composite film stack
AssigneeApplied Materials, Inc.
InventorsHyun Song Joo, David R. Lopes
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Abstract
A method of selectively oxidizing a composite film. According to the present invention a substrate of having a composite film comprising of lower silicon film, a barrier layer, and upper metal film on the barrier layer is placed into a reaction chamber. An inert gas is then fed into reaction chamber to create an inert ambient in the reaction chamber. The temperature of the substrate is then raised or ramped from first temperature to a second temperature in the inert ambient. After the temperature of the substrate is raised to the second temperature the substrate is exposed to an ambient which oxidizes the silicon but which does not oxidize the metal.
Claims20
A method of selectively oxidizing a composite film comprising:
- placing a substrate having a composite film comprising a lower silicon film, a barrier layer and an upper metal film on the barrier layer;
- flowing an inert gas into said chamber to create an inert ambient in said chamber;
- raising the temperature of said substrate from the first temperature to a second temperature in said inert ambient;
- and
- after raising said temperature of said substrate to said second temperature, exposing said substrate to an ambient which oxidizes said silicon film and not said metal film.
A method of selecting oxidizing a composite electrode comprising:
- placing a substrate into a reaction chamber, said substrate having an electrode comprising a lower polysilicon film, a tungsten nitride barrier layer on the polysilicon film, and a tungsten film on the tungsten nitride barrier layer;
- providing an inert gas into said chamber to create an inert ambient in said chamber;
- raising the temperature of said substrate from a first temperature to a second temperature in said inert ambient;
- and
- after raising said temperature of said substrate to said second temperature forming an ambient in said chamber which selectively oxidizes said composite electrode.
A method of selectively oxidizing an electrode comprising:
- placing a substrate into a reaction chamber, said substrate having an electrode comprising a lower polysilicon film, a tungsten nitride barrier layer on the polysilicon film, and a tungsten film on the tungsten nitride barrier layer;
- providing nitrogen gas (N2) into said chamber while raising said substrate temperature from a first temperature of less than 100° C. to a second temperature greater than 800 ° C.;
- after raising said substrate to said second temperature, providing H2 and O2 into said chamber and reacting said H2 and O2in said chamber to form an oxidizing ambient comprising H2 and H2O wherein said oxidizing ambient consist of between 5-20% H2O and between 95-80% H2.
Dependencies are inferred from the claim text.