Browse Prior Art Database

New Contactless Method to Burn-In Bipolar Chips

IP.com Disclosure Number: IPCOM000114006D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Arienzo, M: AUTHOR [+4]

Abstract

Disclosed is a contactless method to burn-in bipolar chips which uses electromagnetic waves to induce currents in metal lines.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 58% of the total text.

New Contactless Method to Burn-In Bipolar Chips

      Disclosed is a contactless method to burn-in bipolar chips
which uses electromagnetic waves to induce currents in metal lines.

This method, coupled with temperature, can be used to burn-in bipolar
chips at wafer level without the need to contact pads or solder
balls.

      Burn-in of bipolar chips is necessary to decrease field fails
and increase machine reliability.  This burn-in is performed in an
oven while the chips are powered and stimulated with random I/O
signals.  The junction temperature of the transistors is kept below
200º  to prevent chip thermal runaway and permanent damage.  The
objective of burn-in, in the specific case of bipolar circuits, is to
accelerate the fails in the metallization layers.  Most of the fails
observed empirically, in fact, are related to the metal layers, and
are thermally activated with an activation energy of approx.  0.5eV,
and can be accelerated by temperature and current.  Therefore, by
powering and heating the chips, currents flows in the metallization
layers, and by combined Joule heating and thermal heating, the chips
having faults will have early life fallout and be eliminated.  The
bipolar transistors do limit the highest currents that can flow in
the metal layers.  Furthermore, to cover 100%  of the metal layers,
all solder balls have to be contacted, necessitating complex
contacting schemes (very high number of solder balls, increasing
rapidly), and cos...