John

Aluminum wire bonding is commonly done with gold thickness of 5 micro
inches. The gold may be deposited by an ENIG process or an electroless
process. From what I have observed, the preference is electrolytic (and
soft of course)gold.

Best regards

Lee

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of John Parsons
Sent: Wednesday, January 12, 2005 6:32 PM
To: [log in to unmask]
Subject: [TN] FAB - Al Wire Bonding

Greetings all,
I am trying to learn something about the wire bonding process.  Our
customer
has a part on which they spec the finish of some edge connector fingers
as
"Gold Plated for Wire Bonding Al Wire".  As we do not provide a wire
bondable gold finish in-house we have subcontracted the service.  The
plating service tells me that typically for Al wire bonding all that is
required is a typical ENIG process (5-10u" Au over 200u" Ni).  I believe
that in past verbal communications with the customer they have said that
an
ENIG finish would not suffice and that they require 15u" of bondable
gold
(electroless gold or electroplated??) .

What say you? Or does "it depend" :-)

Regards
John Parsons

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