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 film on a surface of a semiconductor substrate, the method comprising:
positioning said semiconductor substrate within a deposition chamber; prior to forming any tungsten on the substrate surface, performing an initiation soak, which comprises exposing the surface to a boron-containing compound; exposing the substrate to a tungsten-containing gas that is reduced to form a first portion of a tungsten nucleation layer on the substrate; after forming the first portion of the tungsten-nucleation later, flowing a silane into said deposition chamber; and flowing a tungsten-containing gas into said deposition chamber and reducing the tungsten-containing gas to form another portion of the tungsten nucleation layer, wherein said deposition chamber has multiple stations and wherein one or more stations is used for pulsed nucleation to form the nucleation layer and the remainder of the stations are used for CVD plugfill.