Steve,
While the amount of Be is almost double what you are used to, the total and
interactive effect is still very small in relation to other constituents in
the wire/pad system. You MIGHT notice some minor looping changes if you are
using it in an auto bonder but I have not seen long term reliability issues
or failures associated with Be doping. Years ago I used wire with as much as
15ppm and saw no reliability issues and that was in the day when bonding
metallugy systems were much less pure.
Regards,
Bruce Misner
-----Original Message-----
From: Creswick, Steven [mailto:[log in to unmask]]
Sent: Monday, August 04, 2003 6:03 AM
To: [log in to unmask]
Subject: Re: [TN] Persons with wire bonding experience
Ingemar,
Good morning!
I was thinking more of any long term reliability issues associated with the
higher than normal Be contant rather than shelf life/aging concerns. I am
with you - my 'field aging studies' are very good, but none of them include
wire having >4PPM Be :-(
The aging study (was in George Harman's book) was all that I could find that
mentioned 'elevated' Be contents.
Thanks for the lead. Will check out.
.... and tomatoes are good for us!!
Steve Creswick - Gentex Corporation
A Smarter Vison
-----Original Message-----
From: Ingemar Hernefjord (KC/EMW)
[mailto:[log in to unmask]]
Sent: Monday, August 04, 2003 3:11 AM
To: 'TechNet E-Mail Forum.'; Creswick, Steven
Subject: RE: [TN] Persons with wire bonding experience
Steve, I would contact a good metalurgist. 'Aging' is a question of chemical
or physical changes, slow or fast reactions.Oftenly resulting in
crystalographic changes which have an impact on the ductility, which I
believe is what you are asking for. As far as I understand, a lot is
possible to calculate. Why not ask Andrew Niblett at duPont, Bristol, UK ?
He's got bondwires on his brain.
His adress is: [log in to unmask]
My two pesetas
Ingemar Hernefjord
PS. We treat all bondwires like tomatoes, have to be consumed quickly. Field
'aging': no negative reports last three decades.
-----Original Message-----
From: Creswick, Steven [mailto:[log in to unmask]]
Sent: den 1 augusti 2003 21:50
To: [log in to unmask]
Subject: [TN] Persons with wire bonding experience
All,
Here it is late in the day on Friday, and a surprise pops up.
For many, many years, I have been bonding and keeping tabs on the properties
of the wire we have used.
As with most people, I have been using Be doped wire. In all cases it has
been in the 4-6 PPM range (based on analysis of the wire, not the label on
the blister pack - which usually just parots what we put on the procurement
specification).
Bottom line is that the most recent melt is running at nearly 8 PPM (7.9).
This places me out of range with any 'history' that I might have. I have
seen reports on Aging & Shelf Life Stability testing, probably in one of
George Harman's books. Bottom line was that after 2 years, with <10 PPM Be,
no significant change was noted in tensile strength or % elongation.
However, this was an old study, and a lot of things have changed since then,
with respect to wire manufacture.
Quicky testing of a large number of wires and parts does not reveal any
anomalies, but .... I am wondering if something will hit me up along the
back-side of my head at a later date. Environmental testing would take too
long to be of much use in the immediate situation.
Anyone out there have any comments with respect to deleterious effects of Be
doping in the ~8 PPM range??
Think of non-hermetic packaging, automotove application, high rel.
I am inclined to say no-thanks to this particular wire.
Steven Creswick - Gentex Corporation
A Smarter Vision
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