US 5,913,144 AGranted

Oxidized diffusion barrier surface for the adherence of copper and method for same

AssigneesSharp Microelectronics Technology, Inc., Sharp Kabushiki Kaisha

InventorsTue Nguyen, Lawrence J. Charneski, Lynn R. Allen

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Abstract

A method has been provided for improving the adhesion of Cu to a diffusion barrier material, such as TiN, in an integrated circuit substrate. The diffusion barrier is exposed to either a reactive oxygen species, or a plasma containing oxygen. A thin layer of the diffusion barrier is oxidized, typically less than 50 .ANG., in response to exposure to the oxygen environment. CVD copper is then deposited over the oxidized diffusion barrier surface. The oxide layer improves bonding between the copper and diffusion barrier surfaces. The oxide layer permits the control of tolerances in the diffusion barrier preparation processes, and copper precursor, to be relaxed. An integrated circuit comprising an oxide layer between the diffusion barrier and the copper layer is also provided.

Claims10

Dependent claims

A method of adhering Cu to selected integrated circuit (IC) surfaces, the selected Cu-receiving surfaces being predominately on diffusion barrier material applied to selected regions of the IC, the method comprising the steps of:

a) generating a reactive oxygen species from a predominately oxygen plasma and exposing each selected Cu-receiving surface to the anisotropic etching of the reactive oxygen species, whereby a plasma of reactive ions and radicals combine with the selected surface;
b) in response to the ion etch of Step a), oxidizing a thin layer of the diffusion barrier material surface in response to the oxygen exposure in step a);
c) stopping the exposure of the diffusion barrier material to the oxygen in step a) before the oxide layer formed in step b) exceeds approximately 30 .ANG., whereby the relatively thin oxide layer prepares the diffusion barrier material receiving surface for adhesion to Cu;
and
d) following step c), adhering deposited CVD Cu with the diffusion barrier material surface oxidized in step b), whereby the Cu is adhered to a material which prevents the diffusion of Cu into regions of the IC underlying the diffusion barrier.

2 more elements

Dependencies are inferred from the claim text.