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Refractory Intermetallic Compounds for Local Interconnections

IP.com Disclosure Number: IPCOM000101299D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 1 page(s) / 42K

Publishing Venue

IBM

Related People

Hu, CK: AUTHOR [+2]

Abstract

Disclosed is the use of refractory Al intermetallic compounds for local interconnects, such as TiAl3, TaAl3, WAl12, etc. Such metal lines can also be used as an etch stop for SiO2 RIE.

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Refractory Intermetallic Compounds for Local Interconnections

       Disclosed is the use of refractory Al intermetallic
compounds for local interconnects, such as TiAl3, TaAl3, WAl12, etc.
Such metal lines can also be used as an etch stop for SiO2 RIE.

      The density of VLSI devices can be improved using a local
interconnection scheme which links adjacent devices and is delineated
before the interlevel dielectric deposition (1).  It also reduces the
total number of vertical vias which need to be constructed through
the dielectric.  Although TiSi2, MoSi2, or WSi2 have been proposed as
a local wiring, the refractory Al intermetallic compounds (e.g.,
TiAl3) can also be used as a local wiring. The advantage of use TiAl3
is that it can be easily fabricated, deposited over topography, and
patterned.  In addition, intermetallic compounds provide a good etch
stop for via hole etching in VLSI processing, especially for the
planarized dielectric structures, where there are large variations in
depth.  A good diffusion barrier (e.g., metallic nitride film) under
intermetallic can also be readily provided as part of the process.

      Patterning the TiN/Ti/Al(Cu) local interconnections over 0.7 mm
topographic features by using a reactive ion etching (RIE) process
has been shown (2).  TiAl3 can be formed by annealing the Ti/Al
bilayer lines.  The growth rate of TiAl3 from the Ti/Al bilayer film
is about 100 nm in 30 minutes at 400oC (3).

      Because of its...