Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

High Electromigration Resistance Metallurgy for Back-End-of-Line Applications

IP.com Disclosure Number: IPCOM000112247D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Aboelfotoh, MO: AUTHOR [+5]

Abstract

Disclosed is a new metallurgy with improved electromigration resistance, low electrical resistivity, and reduced stress, which provides a corrosion resistance surface. Current state of the art techniques use a metallurgy based on Al containing 0.5-4 wt.% Cu for the Back-End-of-Line (BEOL) metallizations. The addition of Ge to this composition, provides a solution to electromigration by "stuffing" the grain boundaries of the Al-Cu structure. In addition, the new alloy Al-Cu-Ge, provides a reduction in the film stress, does not change the electrical resistance, and has the unique feature of providing a corrosion resistance surface by the formation of a Cu germanide compound.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 66% of the total text.

High Electromigration Resistance Metallurgy for Back-End-of-Line
Applications

      Disclosed is a new metallurgy with improved electromigration
resistance, low electrical resistivity, and reduced stress, which
provides a corrosion resistance surface.  Current state of the art
techniques use a metallurgy based on Al containing 0.5-4 wt.% Cu for
the Back-End-of-Line (BEOL) metallizations.  The addition of Ge to
this composition, provides a solution to electromigration by
"stuffing" the grain boundaries of the Al-Cu structure.  In addition,
the new alloy Al-Cu-Ge, provides a reduction in the film stress, does
not change the electrical resistance, and has the unique feature of
providing a corrosion resistance surface by the formation of a Cu
germanide compound.

      A sequential deposition of Al containing 0.5-8 wt.  % of Cu,
followed by a layer of Ge was deposited over single crystal Si, or
thermally oxidized Si substrates.  The structure is then annealed at
temperatures in the range of 200 to 300 C for a period of 1 hour in
an atmosphere of forming gas.  Rutherford Back Scattering (RBS)
analysis revealed the following effects after the anneal treatment;
(1)  A thin layer of Cu3Ge is formed near the surface.  This compound
provides a corrosion resistant cap to the Al-Cu alloy.  (2)  Some of
the Ge is dissolved inside the Al-Cu matrix, which is desirable for
two reasons: stress relief in the Al-Cu alloy is achieved, and more
importantly, the excess Ge "stuf...