METHOD FOR PRODUCING ULTRA-THIN TUNGSTEN LAYERS WITH IMPROVED STEP COVERAGE

摘要

A tungsten nucleation film is formed on a surface of a semiconductor substrate by alternatively providing to that surface, reducing gases and tungsten-containing gases. Each cycle of the method provides for one or more monolayers of the tungsten film. The film is conformal and has improved step coverage, even for a high aspect ratio contact hole.

主权项

1. A method of forming a tungsten nucleation layer a surface of a semiconductor substrate comprising the steps of:
positioning said semiconductor substrate at a deposition station within a deposition chamber; heating said semiconductor substrate to a temperature between approximately 250 to 475° C. at said deposition station; performing an initiation soak step, which consists of exposure of the substrate to a gas in a gaseous or plasma state for about 2 to about 60 seconds; flowing a reducing gas into said deposition chamber whereby about one or more monolayers of reducing gas are deposited onto said surface of said substrate; purging the reducing gas from the deposition chamber; and flowing a tungsten-containing gas into said deposition chamber, whereby said deposited reducing gas is substantially replaced by tungsten to provide said nucleation layer.