Hi Steve - I echo your gold wire bond experiences with ENIG, I have tried a
number of times to develop a gold wirebond process but have not achieved
consistent success. There are lots of folks who have implemented very
successful Al wirebond process to ENIG (the IPC 4552 committee talked with
many of those folks as the specification was developed). Your question on
electroless Ni/Pd/Au - I consider that finish the "silver bullet" finish
for the industry. It is both solderable and wirebondable which is a real
enabler. However, it isn't a cheap finish and its availability is pretty
restricted as few pwb fabricators have it in their shops.
Dave Hillman
Rockwell Collins
[log in to unmask]
"Creswick,
Steven"
<SCreswick@GENTEX To
.COM> [log in to unmask]
Sent by: TechNet cc
<[log in to unmask]>
Subject
Re: [TN] wire bonding - ENIG and
10/12/2005 05:25 ENEPIG
AM
Please respond to
TechNet E-Mail
Forum
<[log in to unmask]>
; Please respond
to
"Creswick,
Steven"
<SCreswick@GENTEX
.COM>
George,
I strongly ditto your comments on theromosonic gold bonding to ENIG -
electroless nickel, immersion gold. I have not been able to obtain a
stable process with theromsonic gold wire bonding and ENIG. If someone
has, I would certainly like to hear and learn.
With aluminum ultrasonic wedge bonding, we are attempting to bond through
the gold layer - actually bonding to the nickel below. With thermosonic
gold bonding we are attempting to bond to the gold. Being very thin, and
usually very hard [compared to thick electrolytic gold], thermosonic gold
bonding is not a very stable process.
Just out of curiousity, where do you feel that ENEPIG [electroless Ni -
electroless Pd - immersion Au] lays in the ultrasonic aluminum &
thermosonic gold wire bonding spectrum?
Would you lump elecrolytic Ni-Pd-Au in the same category/s as the
electroless Ni-Pd-Au?
I would generally like to open that question up to any of the other bath
suppliers/users on TechNet as well. We have some very knowledgeable
individuals out there...
At the present time, I have some very strong interest in the ENEPIG
process, and its suitablity for thermosonic gold wire bonding.
FYI - Back in the late 80's or so, with Dr. Joe Abys and Lucent
Technologies thermosonic gold bonding to ELECTROLYTIC Ni-Pd-Au was pretty
much a dial and forget type of process. Agreed, it took some effort to
come up with a suitable bond schedule [and capillary], but it appeared to
be quite stable, once determined. It definitely is different than the
pure, soft, electrolytic golds of my [innocent] youth in the Mil and
implantable medical arenas, but nonetheless appeared to work well.
Interested in your comments ..
Steve Creswick - Gentex Corp
-----Original Message-----
From: George Milad [mailto:[log in to unmask]]
Sent: Tuesday, October 11, 2005 7:43 PM
To: [log in to unmask]
Subject: Re: [TN] <List>[TN] wire bonding
No soldering material of any kind is used in wire bonding.
It is based on the compatibility of metals and their ability to fuse into
each using ultrasound energy for aluminum wire and heat the ultrasound for
bonding gold wire.
For your info ENIG is a good surface for aluminum wire bonding, not so for
gold wire bonding.
Best regards
George Milad
[log in to unmask]
National Accounts Manager for Technology
Uyemura International Corporation
Technical Center
240 Town LIne Rd
Southington CT 06489
(516) 901 3874 (mobile)
(860) 793-4011 (office)
(860) 793-4020 (fax)
-----Original Message-----
From: Kathy [mailto:[log in to unmask]]
Sent: Tuesday, October 11, 2005 3:42 PM
To: [log in to unmask]
Subject: [TN] wire bonding
Question for the assemblers:
When wirebonding to ENIG, do you use any solder paste or other
"facilitator"
to create the bond?
Thanks for your reply...
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