Hello Neal.

Try some of these sources. I have used them many years ago when we had
problems. I assume that you are aware that problems seldom occur until
you run lots of current and/or exceed +125C.

re 1: IEEE 82 Proc. IRPS "The influence of contaminations on
aluminium-to-gold intermetallics" by Charles, Romanesco et al at Applied
Physics Labs, Maryland.

re 2: IEEE 82 CH1781-4/82/0000-0421500 "Low Temperature void formation
jin gold-to-aluminium contacts" by Plunkett at Sandia Labs Albuguerque
New Mexico.

re 3:IEEE 82 CH1990-1/84/0000-0037 "Epoxy Degradation Induced Au-Al
Intermetallics void formation in Plastic encapsulated MOS memories, by
Rebecca J.Gale at AT&T Bell Labs, PA.

re 4: IEEE 91 0569-5503/91/0000-0859, "Resistance drift in Aluminium to
Gold US Wire bonds, by Robert M. Murcko et al at IBM Endicott NY.

re 5: "The resistance increase in Gold-to-Aluminium interconnects with
time and temperature" by D.W.Bushmire at Sandia Labs Alb. New Mexico

re 6: "Ambient Effects on Gold-Aluminium Bonds" by Thomas J.Rossiter at
Romw Air Development Center, Griffis Air Force Base, NY.

re 7:"Gold Aluminium Interconnect stability on Thin Film Hybrid
Microcircuit Substrates" by D.W.Bushmire at Sandia Labs, Alb. New Mexico

re 8: "Metallurgical Aspects of Aluminium wire bonds to Gold
Metallization" by James L. Newsome at Honeywell Inc Aerospace Div,
St.Petersburg, Fl.

re 9:"Failure Modes and Mechanisms in Electronic Packages" by
Viswanadham Singh. Can be ordered at [log in to unmask]

I also recommend you to speak with Erich Polzer at duPont if you want to
know what dopants should be used in the gold to reduce intermetallic
growth. His e-mail is [log in to unmask]

If you think of PWBs I'm sure you have a lot of references already, if
not try Simon Huetter at Optiprint e-mail [log in to unmask]
I suppose you are already drowned by information in the matter.

                                     Good Luck!
                                   Ingemar Hernefjord
                                 Ericsson Microwave System

PS. This information is sent also to my friends within Ericsson. DS.

-----------------------------------------------------------------------
> I am looking for more recent material on the growth, care and feeding
of
> Au/Al intermetallics in gold ball on aluminum IC pad wire bonds than
George
> G. Harman's excellent though all too brief book, "Wire Bonding In
> Microelectronics" with a 1989 copyright.  More specifically, I am
interested
> in known contaminants that reduce the time and/or temperature
components
> required to grow the intermetallic layer.  I would also like to know
what a
> "typical" intermetallic layer thickness is, if there is such a thing
as
> typical.
>
> I would greatly appreciate if someone would at least refer me to
relevant
> material.
>
> Thank you.
>
> Neal Forss
>
> fax:    (408) 738-8364
> work:  (408) 522-6304
> email:  [log in to unmask]

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