Selective cobalt deposition on copper surfaces

Abstract

Embodiments of the invention provide processes to selectively form a cobalt layer on a copper surface over exposed dielectric surfaces. In one embodiment, a method for capping a copper surface on a substrate is provided which includes positioning a substrate within a processing chamber, wherein the substrate contains a contaminated copper surface and a dielectric surface, exposing the contaminated copper surface to a reducing agent while forming a copper surface during a pre-treatment process, exposing the substrate to a cobalt precursor gas to selectively form a cobalt capping layer over the copper surface while leaving exposed the dielectric surface during a vapor deposition process, and depositing a dielectric barrier layer over the cobalt capping layer and the dielectric surface. In another embodiment, a deposition-treatment cycle includes performing the vapor deposition process and subsequently a post-treatment process, which deposition-treatment cycle may be repeated to form multiple cobalt capping layers.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]Embodiments of the invention generally relate to a metallization process for manufacturing semiconductor devices, more particularly, embodiments relate to preventing copper dewetting by depositing cobalt materials on a substrate.[0003]2. Description of the Related Art[0004]Copper is the current metal of choice for use in multilevel metallization processes that are crucial to semiconductor device manufacturing. The multilevel interconnects that drive the manufacturing processes require planarization of high aspect ratio apertures including contacts, vias, lines, and other features. Filling the features without creating voids or deforming the feature geometry is more difficult when the features have higher aspect ratios. Reliable formation of interconnects is also more difficult as manufacturers strive to increase circuit density and quality.[0005]As the use of copper has permeated the marketplace because of its relative ...

AI Technical Summary

Benefits of technology

[0009]Embodiments of the invention provide processes to selectively form a cobalt layer on a copper surface over exposed dielectric surfaces. In one embodiment, a method for capping a copper surface on a substrate is provided which includes positioning a substrate within a processing chamber, wherein the substrate contains a contaminated copper surface and a dielectric surface, exposing the contaminated...

Problems solved by technology

Filling the features without creating voids or deforming the feature geometry is more difficult when the features have higher aspect ratios.

Reliable formation of interconnects is also more difficult as manufacturers strive to increase circuit density and quality.

Each processing method may increase the likelihood of errors such as copper diffusion across boundary regions, copper crystalline structure deformation, and dewetting.

These options are costly or only partially effective or both.

The stress migration and electromigration of copper across the dielectric layers or other structures increases the resistivity of the resulting structures and reduces the reliability of the resulting devices.

PVD processes to deposit cobalt are often hard to control precise deposition thicknesses.

CVD processes usually suffer from poor conformality and contaminants in the deposited cobalt layer.

However, the deposition rates of an ALD process are often too slow, so that ALD processes are not often used in commercial applications.

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