Never heard of 'degassing' a bath...would Gaviscon help? That was a joke.

I cannot see a plating bath ever being free of bubbles, whether they're from
air-agitation, (of which an hydraulic eductor system would diminish or
eliminate) or formed during plating, i.e. hydrogen gas. As for
super-saturated solution, well if I found the bath to be super-saturated I
would look for leaks in plumbing as we have not used air-agitation in years.

Bubbles will in my opinion always be a part of electroplating copper. To
prevent them from causing problems, especially on microvia or high aspect
product you need a mechanical (we use air-vibrated racks which literally
bimp and shake bubbles lose) means to prevent them from causing damage.

Bubbles attach to product due to the surface tension (not being a physicist
I will not even attempt to describe the means in which the surface tension
causes adherence) and it is the mechanical (bump) that is needed to ensure
they do not remain on product, in the holes, or on the edges, etc.

Franklin


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of EIMCNews
Sent: Thursday, February 23, 2006 5:41 PM
To: [log in to unmask]
Subject: Re: [TN] Board etching question for you board shops out there.

Scott,

I've been reading the posts replying to this question.  From your
description and the responses from others, the problem sounds very much to
be a copper plating issue.  Specifically, super saturated air in the plating
solution causes this.  Pits, mouse bites or whatever you want to call them
are one of the reasons more advanced shops have gone to airless agitation in
their copper plating baths.

One of the dry film suppliers did a huge study on this years ago when pits
were a general problem and driving board fabs crazy trying to find a
solution.  No question that developing/rinsing issues can exacerbate the
problem.  Further, some films will develop OK but leave a sidewall that has
striations that can catch and hold air bubbles.  If you've looked at the SEM
of a resist sidewall you can see that some films are worse than others in
how clean their sidewalls look after developing.  Simply turning off the air
in a plating bath and running boards as a test won't really work unless your
fab lets the bath sit for 24 hours (without any air agitation) to properly
de-gas.

Sincerely,

Roger Mouton

EIMC - Advanced Plating Technologies
www.smartcatshield.com
[log in to unmask]

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
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 or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------