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Oxidizable Fuse for Integrated Circuit Personalization and Redundancy

IP.com Disclosure Number: IPCOM000121739D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 43K

Publishing Venue

IBM

Related People

Geffken, RM: AUTHOR [+2]

Abstract

A method is outlined for providing an oxidizable fuse or metal link which can be altered electrically (or by other means) while leaving the overlying passivation intact.

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This is the abbreviated version, containing approximately 71% of the total text.

Oxidizable Fuse for Integrated Circuit Personalization and Redundancy

      A method is outlined for providing an oxidizable fuse or
metal link which can be altered electrically (or by other means)
while leaving the overlying passivation intact.

      Topography associated with VLSI and SRAM technologies requires
redundancy fusing to be a part of the metal wiring structure rather
than polysilicon levels. Passivation of these blown metal fuses can
be a problem because of the many chip pads subject to being shorted.
A process is shown which allows fusing by oxidation of metal fuse
links, leaving the overlying passivation intact.

      Step 1.  A layer of interconnection metallurgy is deposited on
a SiO2 insulator. The initial metal layer (400 - 1000 angstroms
thick) should provide good adhesion and contact to the substrate and
subsequent metal layer deposited. Also, the initial metal layer must
be capable of thermodynamically reducing SiO2 . Titanium is the
preferred embodiment; however, Hf (Hafnium) or Zr (Zirconium) are
also acceptable. The final layer of interconnect metallurgy should be
any of a multitude of low resistance metals, e.g., Al, Al-Cu or other
alloys of copper.

      Step 2.  The composite layer of Ti-AlCu is patterned and dry
etched utilizing standard techniques to define interconnect and fuse
locations.

      Step 3.  To open a window over the fuse area, a block photo
mask is applied and exposed.

      Step 4.  Standard Al we...