Frank,
Two thoughts:
1. Are your NPTHs drilled, run through electroless copper,
tented then etched out? If so, check to make sure you etch
all of the metal out of these holes before going through
'chemical' Ni/Au (is this electroless nickel, immersion
gold?)
2. Are you using a palladium catalyst on your electroless
Ni, immersion gold line? Leaving some of this catalyst in
the NPTHs will cause plate out in these holes. I've
certainly seen plateout on laminate areas with these
not-so-stable catalysts even with good rinsing after the
catalyst step. When this begins to happen, changing out the
catalyst seemed to be the only thing which worked to get rid
of this plateout.
To check out the second of these ideas, run some NPTH test
boards through the electroless nickel, immersion gold line
skipping the catalyst and catalyst rinse steps. If the
plating in NPTHs goes away, yet returns when you go through
the catalyst and rinse, you've come close to pinpointing the
source of your plateout.
I hope this helps.
Regards,
Dave Sullivan
Rockwell Collins, Inc.
[log in to unmask]
______________________________ Reply Separator _________________________________
Subject: chemical Ni/Au in NPTH.
Author: [log in to unmask] at ccmgw1
Date: 4/15/97 3:48 AM
Hello everybody,
Now and than we are seeing that chemical Ni/Au is covering the NPTH
wall. We and also the supplier of chemicals doesn't know what is causing
this phenomenon.
Is there somebody out there who does?
Any help would be appreciated.
Frank Petit
ACB
Belgium
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]> *
* with <subject: subscribe/unsubscribe> and no text in the body. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
Received: from by ccmgw1.cacd.rockwell.com (SMTPLINK V2.11)
; Tue, 15 Apr 97 03:48:01 cst
Return-Path: <[log in to unmask]>
Received: from stealth.cacd.rockwell.com (stealth) by mailserv with ESMTP
(1.40.112.8/16.2) id AA084394082; Tue, 15 Apr 1997 03:48:02 -0500
Received: by stealth.cacd.rockwell.com; id DAA14113; Tue, 15 Apr 1997 03:45:35 -0500
Received: from unknown(168.113.24.64) by stealth.cacd.rockwell.com via smap (3.2)
id xma014110; Tue, 15 Apr 97 03:45:25 -0500
Received: from ipc.org by simon.ipc.org via SMTP (940816.SGI.8.6.9/940406.SGI)
id DAA12338; Tue, 15 Apr 1997 03:35:28 -0700
Resent-Date: Tue, 15 Apr 1997 03:35:28 -0700
Received: by ipc.org (Smail3.1.28.1 #2)
id m0wH3IQ-000Bj1C; Tue, 15 Apr 97 03:08 CDT
Resent-Sender: [log in to unmask]
Old-Return-Path: <[log in to unmask]>
Message-Id: <[log in to unmask]>
From: frp <[log in to unmask]>
To: "[log in to unmask]" <[log in to unmask]>
Subject: chemical Ni/Au in NPTH.
Date: Tue, 15 Apr 1997 10:17:59 +0100
X-Mailer: Microsoft Exchange Server Internet Mail Connector Version 4.0.837.3
Encoding: 12 TEXT
Resent-Message-Id: <"jdDAa2.0.NgI.LUpKp"@ipc>
Resent-From: [log in to unmask]
X-Mailing-List: <[log in to unmask]> archive/latest/11949
X-Loop: [log in to unmask]
Precedence: list
Resent-Sender: [log in to unmask]
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]> *
* with <subject: subscribe/unsubscribe> and no text in the body. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
|
