All;
As previously mentioned, the IPC-2221, Generic Standard on Printed Board
Design, is currently in committee, as a replacement for the current
IPC-D-275. It contains a much expanded table on copper finishes, which
includes the thinner gold and nickel requirements you have all eluded to.
Sincerely,
Gary Ferrari
Chairman - IPC-D-275
At 11:33 AM 4/24/96 -0500, George Franck X2648 N408 wrote:
>Be sure to note that the 3-8 microinches that Tracy calls out is much less
>than the minimum 50 microinches that IPC-D-275 Table 3-8 calls out. There
>has been a large shift in the use of Gold as a replacement for solder which
>has not been reflected in the IPC specs. (OK, OK, The IPC guys will
>probably prove me wrong, but I haven't found it in my small cache of
>Specs.)
>
>A lot of this shift is due to getting fine pitch pads flat, PWB
>solderability shelf life issues, no clean solder process improvements, and
>to a (much) lesser degree the pursuit of an enviromentally-friendly
>"unleaded" PWB.
>
>Steve,
>When will the snows start in New South Wales? Have a great winter! ;-)
>
> ====================================================================
> George Franck
> PWB Product Assurance Phone (703) 560-5000 x2648
> E-Systems M/S N408 Fax (703) 280-4613
> 7700 Arlington Blvd E-Mail: [log in to unmask]
> Falls Church Va 22046 E-Mail: [log in to unmask]
> ====================================================================
>
>
>>You're going to need to spec a nickel underlayer (barrier and soldered to)
>>and a max gold thickness to prevent voiding and gold embrittlement of solder
>>joints.
>>
>>We spec that the nickel be an electroless nickel/immersion gold process be
>>used and that the nickel thickness is a minimum of 100 microinches followed
>>by 3 - 8 microinches of 99.9% gold. The gold is also soft, <90 Knoop, and
>>can be wire bonded to. This gold finish is a Type III Hardness Grade A
>>strike according to MIL-G-45204.
>>
>>The immersion gold process is electroless but self limiting, nickel is
>>displaced and replaced by gold. As soon as the surface layer of nickel is
>>no longer exposed, the plating process comes to a halt. Depending on who/what
>>PCB shop or chemical supplier you talk to, the resultant gold thickness is in
>>the 2 - 12 microinch range.
>>
>>Tracy Tennant
>>[log in to unmask]
>>
>> ---------- Start of forwarded message ----------
>>
>> Message#
802373
>> 24-APR-1996
06:42:42.00
>>From: [log in to unmask]
>>To: STHUMMEL,TTENNANT,[log in to unmask]
>>Subj: Re: Gold Flash on PWB's
>>
>>
>>Received: from micron.co by BOGEN4 Wed, 24 APR 96 06:42:13 MDT
>>Received: from is04.micron.com by micron.com (SMI-8.6/SMI-SVR4)
>> id GAA01635; Wed, 24 Apr 1996 06:41:51 -0600
>>Received: from simon.ipc.org ([168.113.24.64]) by relay.micron.com with
>>SMTP id
>> <185386>; Wed, 24 Apr 1996 06:42:11 -0600
>>Received: from ipc.org by simon.ipc.org via SMTP (940816.SGI.8.6.9/940406.SGI)
>> id HAA28011; Wed, 24 Apr 1996 07:40:35 -0700
>>Resent-Date: Wed, 24 Apr 1996 08:40:35 -0600
>>Received: by ipc.org (Smail3.1.28.1 #2)
>> id m0uC3AT-00007KC; Wed, 24 Apr 96 06:55 CDT
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>>Date: Wed, 24 Apr 1996 08:01:25 -0600
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>>To: [log in to unmask]
>>Resent-To: <[log in to unmask]>
>>Resent-To: <[log in to unmask]>
>>Resent-To: <[log in to unmask]>
>>Subject: Re: Gold Flash on PWB's
>>Resent-Message-ID: <"LqCG41.0.HA9.mQXVn"@ipc>
>>Resent-From: [log in to unmask]
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>>
>> STEPHEN,
>> IPC-D-275 SECT 3.8.4.3 (SOUNDS LIKE A STAR DATE DOESN'T?),
>> CONTAINS INFORMATION ON GOLD PLATING. ALSO REFERENCE SECTION 3.8.4.4
>> ON NICKEL UNDERPLATING. TABLES 3-8 AND 3-9 WILL GIVE YOU AN IDEA OF
>> WHAT YOU NEED FOR YOU'RE END PRODUCT. AS TO WETHER IT'S WORTH IT, YOU
>> MUST CONSIDER YOUR END USAGE AND THEN TALK WITH YOU'RE FAB HOUSE.
>> REGARDS,
>>
>> ROB BUTTERWORTH
>> SR PWB DESIGNER
>> ADC VIDEO SYSTEMS
>> 999 RESEARCH PARKWAY
>> MERIDEN, CT 06450
>> [log in to unmask]
>>
>>
>>______________________________ Reply Separator
>>_________________________________
>>Subject: Gold Flash on PWB's
>>Author: [log in to unmask] at internet-mail
>>Date: 4/24/96 2:52 AM
>>
>>
>>Can anyone supply a specification to call up when requesting a Gold
>>Flash finish on a PWB and is it worth it today, with the advances
>>with the HASL finishes.
>>
>>Regards
>>
>>Stephen Cooper
>>Manufacturing Projects Manager
>>SCITEC LIMITED
>>Apollo Place
>>Lane Cove NSW 2066
>>Australia
>>PH : +612 428 9500
>>Fax : +612 428 9589
>>Email : [log in to unmask]
>>
>>
>>
>>
>>
>
>
>
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