Method for forming a metal plug

摘要

A method for forming a metal plug is provided. The method is used to form a metal plug without a hole on a glue/barrier layer within a trench when the glue/barrier layer has been formed for a while. A substrate with a trench therein and a glue/barrier layer formed conformal to the profile of the substrate is provided. A post-treatment is performed on the glue/barrier layer to prevent moisture absorption and to make the glue/barrier become dense. The post-treatment comprises a plasma treatment or a deep UV plus laser treatment. After performing the post-treatment step, a metal layer is formed on the glue/barrier layer at least to fill in the trench. The metal layer other than that filling the trench is removed to form a metal plug.