Copper film containing tungsten nitride for improving thermal stability, electrical conductivity and electric leakage properties and a manufacturing method for the copper film

Abstract

A copper film containing tungsten nitride is manufactured by co-sputtering method under an Ar / N2 atmosphere and has a composition in ratio of tungsten nitride contained in the copper layer in atomic ratios of more than 97.5% in copper, 0.5 to 1.5% in tungsten and of less than 2.0% in nitrogen. By adding the tungsten nitride, the copper film has improvements in thermal stability, good electrical conductivity and low electrical leakage current. Moreover, the copper film attached on a silicon substrate will generate a self-passivated silicon compound layer to serve as a diffusion barrier layer between the copper film and the silicon substrate during annealing.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a copper film, and more particularly to a copper film that contains insoluble tungsten nitride in saturated situation to improve thermal stability, electrical conductivity, and electric leakage of the copper film by magnetron sputtering. A manufacturing method for the copper film is also disclosed in the present invention. [0003] 2. Description of Related Art [0004] Because cupric materials such as copper and cupric alloy have excellence in each of electrical conductivity, thermal conductivity, and mechanical properties at room temperature, these cupric materials are commonly used in the semiconductor field. However, these cupric materials have poor mechanical properties at high temperatures and thus are used at low operational temperatures, whereby the cupric materials can not be used efficiently and temperature limitation restricts further applications of these cupric materials. [0...

AI Technical Summary

Benefits of technology

[0015] A first main objective of the present invention is to provide a copper film that contains dilute tungsten nitride, whereby the copper film has fine crystallites in microstructure, excellent electrical conductivity, low electric leakage current, and good thermal stability at high temperatures.

[0024] By using the nitrides in the copper film, nitrogen atoms efficiently fill into boundaries of the copper crystallites to make the copper crystallites fine in microstructure. Moreover, nitrogen in the copper film is precipitated at the boundaries of the copper crystallites and reacts with the silicon substrate to compose a self-passivated silicon compound barrier layer) to reduce diffusion of the copper atoms.

Problems solved by technology

However, these cupric materials have poor mechanical properties at high temperatures and thus are used at low operational temperatures, whereby the cupric materials can not be used efficiently and temperature limitation restricts further applications of these cupric materials.

However, the copper films still have some drawbacks such as forming an oxidation membrane, reacting with silicon substrate at low temperature or having poor attachment thereby further incurring damages in the semiconducting elements.

Images