Method of forming a conductive contact

Abstract

Conductive contacts in a semiconductor structure, and methods for forming the conductive components are provided. The method comprises depositing a conductive material over a substrate to fill a contact opening, removing excess material from the substrate leaving the contact within the opening, and then heating treating the contact at a high temperature, preferably with a rapid thermal anneal process, in a reactive gas to remove an undesirable component from the contact, for example, thermal annealing a TiCl4-based titanium nitride in ammonia to remove chlorine from the contact, which can be corrosive to an overlying aluminum interconnect at a high concentration. The contacts are useful for providing electrical connection to active components in integrated circuits such as memory devices. In an embodiment of the invention, the contacts comprise boron-doped and / or undoped TiCl4-based titanium nitride having a low concentration of chlorine. Boron-doped contacts further possess an increased level of adhesion to the insulative layer to eliminate peeling from the sidewalls of the contact opening and cracking of the insulative layer when formed to a thickness of greater than about 200 angstroms in a high-aspect-ratio opening.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001] This application is a continuation of U.S. Ser. No. 09 / 941,533, filed Aug. 29, 2001 (now U.S. Pat. No. 7,067,416).FIELD OF THE INVENTION [0002] The present invention relates to the field of semiconductor device fabrication, and more particularly to methods for making conductive contacts in the formation of a semiconductor device. BACKGROUND OF THE INVENTION [0003] As semiconductor fabrication moves toward maximizing circuit density, electrical components are formed at a number of layers and different locations. This requires electrical connection between metal layers or other conductive layers at different elevations in the substrate. Such interconnections are typically provided by forming a contact opening through insulating layer to the underlying conductive feature. With increasing circuit density, the dimensions of openings for electrical contacts become narrower and deeper, posing a challenge to provide adequate conductive fill with...

AI Technical Summary

Benefits of technology

The method provides conductive contacts with enhanced adhesion and reduced chlorine content, preventing peeling and cracking, and ensuring effective electrical contact without compromising conductivity, thus overcoming limitations of tungsten plugs and pure TiCl4-based titanium nitride films.

Problems solved by technology

Pure TiCl4-based titanium nitride fills do not adhere well to the surface of insulative sidewalls of a contact opening, and can also cause the insulative layer to crack due, at least in part, to the pressure exerted when the thickness of the fill within the contact opening is about 200 angstroms or greater.

However, one drawback of titanium nitride films formed from TiCl4, including the boron-doped films described herein, is that the chlorine (Cl2) within the formed contact can diffuse into an overlying material, for example, an overlying interconnect of aluminum, and corrode and ruin the device.

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