Browse Prior Art Database

Aluminum-Tungsten-Aluminum Sandwich for Semiconductor Chip Wirebond Pad

IP.com Disclosure Number: IPCOM000118752D
Original Publication Date: 1997-Jun-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Bombardier, SG: AUTHOR [+6]

Abstract

Disclosed is a sandwich structure for a semiconductor chip wirebond pad. The sandwich is comprised of a first-aluminum film, a continuous tungsten film, and a second-aluminum film wherein the tungsten film is positioned between the first- and second-aluminum films.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 54% of the total text.

Aluminum-Tungsten-Aluminum Sandwich for Semiconductor Chip Wirebond
Pad

      Disclosed is a sandwich structure for a semiconductor chip
wirebond pad.  The sandwich is comprised of a first-aluminum film, a
continuous tungsten film, and a second-aluminum film wherein the
tungsten film is positioned between the first- and second-aluminum
films.

      An alternate version of the wirebond pad structure is also
disclosed wherein the tungsten is non-continuous across the bondpad
forming an area in which the first-aluminum film contacts the
second-aluminum film and the connecting area is surrounded by
tungsten.

      A typical semiconductor chip has thousands of small (e.g., 1 um
diam) vias forming interconnect between within-chip metal wiring
levels and perhaps a dozen large (e.g., 100 um x 100 um square) vias
for chip-to-package wiring bondpads.

      Historically, all structures within the chip have been removed
from below Aluminum bondpads due to bondpad peeling or cracking.
Aluminum (soft) over Dielectric (hard) with Aluminum (soft) below can
result in cracked Dielectric.  A sea of small Tungsten Stud Vias in
the bondpad between Last Metal Aluminum and Last-Metal-Minus-One
Aluminum can also result in wirebond failures due to cracked
Dielectric and Tungsten dissolved during subsequent processing.
Changing the underlying Aluminum layer and/or small Tungsten Stud
layout with either of these options can produce unacceptably high
bondpad resistance and resulti...