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Abstract

A process for applying a TiN contact/via adhesion layer to high aspect ratio contact/via openings etched in a dielectric comprises providing a first layer of TiN on the bottom of the contact/via openings and then depositing the second layer of TiN on the first layer of TiN and on the sidewalls of the contact/via openings. The second layer of TiN serves as the contact/via adhesion layer for structurally supporting the adhesion of a tungsten plug in the contact/via openings. In the case where a contact is etched in the dielectric down to a junction with a titanium silicide layer on top, the first layer of TiN on the bottom of the contact opening is provided by a rapid thermal anneal in a nitrogen-containing atmosphere which converts the top part of the titanium silicide layer in the contact into a barrier TiN layer. Alternatively, in the case where a contact is etched in the dielectric down to an underlying barrier TiN layer, the first layer of TiN on the bottom of the contact opening can be provided by a contact etch which is able to stop on an underlying barrier TiN layer with minimum TiN loss. In the case where a via is etched in the dielectric down to an underlying TiN anti-reflection coating on top of a metal layer, the first layer of TiN on the bottom of the via is provided by a via etch which is able to stop on the underlying TiN anti-reflection coating on top of the metal layer with minimum TiN loss.

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