Browse Prior Art Database

Method of Eliminating Ta Hydride Formation During Cu Plating On Ta Films

IP.com Disclosure Number: IPCOM000122454D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 40K

Publishing Venue

IBM

Related People

Colgan, EG: AUTHOR [+1]

Abstract

Copper, due to its lower electrical resistivity and high melting point, when compared to Al or Al-Cu alloys, is an attractive material for integrated-circuit wiring applications. For VLSI applications, it is essential to fill narrow lines and features without voids in dielectric films. From cost considerations, one of the most attractive methods of depositing Cu in high aspect ratio VSLI features is by the electroless Cu process.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 80% of the total text.

Method of Eliminating Ta Hydride Formation During Cu Plating On Ta
Films

      Copper, due to its lower electrical resistivity and high
melting point, when compared to Al or Al-Cu alloys, is an attractive
material for integrated-circuit wiring applications.  For VLSI
applications, it is essential to fill narrow lines and features
without voids in dielectric films.  From cost considerations, one of
the most attractive methods of depositing Cu in high aspect ratio
VSLI features is by the electroless Cu process.

      Because dielectric degradation due to Cu migration into the
dielectric is a serious concern, it is essential to interpose a thin
barrier film between Cu and the dielectric. The barrier film is
required to provide good adhesion between the insulator and Cu, and
serve as a diffusion barrier both for oxygen and other contaminants
diffusing into the Cu and Cu diffusing out from the wiring.  In the
electroless Cu process, the barrier film plays an additional critical
role, the suppression of blister formation.  The blisters are the
result of the preferential segregation of H2 produced during Cu
reduction into the barrier film.  The resulting gas pressure causes
local delamination and swelling, often referred to as blisters.

      We have solved the blister problem during electroless Cu
plating, by using a reactively sputtered Ta(N) layer as a barrier for
Cu [*].  We found that H2 uptake is at least ten times (10X) lower in
Ta(N) films than that obs...