Browse Prior Art Database

Conducting Metal Oxides (Ruo2) As Diffusion Barriers for Copper

IP.com Disclosure Number: IPCOM000102076D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 34K

Publishing Venue

IBM

Related People

Aboelfotoh, MO: AUTHOR [+4]

Abstract

This article describes a structure which prevents contact copper from diffusing into the shallow junction and protects shallow junction integrity.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Conducting Metal Oxides (Ruo2) As Diffusion Barriers for Copper

       This article describes a structure which prevents contact
copper from diffusing into the shallow junction and protects shallow
junction integrity.

      Copper is currently being considered as possible
back-end-of-the-line metallization.  However, it is very well known
that copper diffuses relatively easily into silicon at moderately
high temperatures producing deep-level defects in Si which, in turn,
result in severe degradation of the electrical characteristics of
devices, such as Schottky-barrier contacts and p-n junctions.  Ta, V
and Nb have recently been proposed as effective copper diffusion
barriers.  However, all existing experimental data show that Ta and V
are not effective as barriers for Cu even at temperatures as low as
350oC.

      This article proposes the use of the conducting oxide, such as
RuO2, reactively sputtered with 80% oxygen in the sputtering chamber
as an effective Cu diffusion barrier. Experimental data show that
RuO2 (80% O2) can act as an effect Cu diffusion barrier to Cu
diffusion up to 550oC.  An alternative structure which has also been
found to be effective as Cu diffusion barrier consists of a thin
layer of Al having thickness of 50Ao or less over a layer of RuO2,
then followed by a copper layer on top of the aluminum layer.  This
structure has been found to be stable against copper diffusion up to
600oC for 30 minutes in Ar and N2 .