It's been a long time since I've done any gold electroplating, but... one thing I remember is that the gold plate is too thin too have any significant influence on the surface topography. Any pits or nodules are most likely due to the underlying copper, sometimes to the nickel, but highly, highly unlikely to be due to the gold. So, focus first on the copper process, then on the nickel process.
Much more troubleshooting info can be found in Section 10.0 (Electroplating) of IPC-PE-740, Troubleshooting Guide for Printed Board Manufacture and Assembly. Section 10.6 deals with gold plating.
Patty
Patricia J. Goldman
PPG Industries, Inc.
724-274-3417
[log in to unmask]
-----Original Message-----
From: Chuck Brummer [mailto:[log in to unmask]]
Sent: Wednesday, September 05, 2001 5:01 PM
To: [log in to unmask]
Subject: Re: [TN] phenomenon with Ni/Au plating
Wow,
Does the board shop purchase their laminate by peel strength. For fine features we use a low
profile copper, which of course has lower peel. Here you may have copper left behind from a
very large copper tooth structure. If the gold is electrolytic (amazing how often we write
about that recently) the plating will grow faster on the high current density points.
If print and etch copper, not a pattern plate job, then there may have been resist residue
that protected copper at the foot of the trace (inadequate development). If this is the case
you would see this on the traces under the mask.
Cross section will tell you the most.
Chuck Brummer
Acuson
"Busko, Wolfgang" wrote:
> Hi all,
>
> I got some new pictures on Steveīs page
> http://stevezeva.homestead.com/index.html
> <http://stevezeva.homestead.com/index.html> .
> They show an interesting phenomenom that obviously occurred during Ni/Au
> plating.
> These "pimples" and "pumples" at the base of the metallic structure right on
> the FR4 surface that surround the pads look like miserable paintwork, yanno,
> like if you paint your windowframes yourself.
> Has anybody seen something similar before and what could have caused that
> and what would you think would be the risk if we use those boards.
>
> We have to come to a quick decision and canīt afford to wait for a
> laboratory result.
>
> Thanks in advance
>
> Wolfgang
>
>
> ---------------------------------------------------------------------------------
> Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL
> Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
> Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
> ---------------------------------------------------------------------------------
---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
