Robert,
The things I would look at are solder pot temperature, material Tg,
thickness of the copper plating.
If I was you I would measure the temperature of the solder pot in
several areas. (Different depths) Don't rely on the temperature read
out. We have seen major temperature differences in our pot. Very
common if one of your heaters is out. (The remaining heaters are
running too hot trying to keep the pot to temperature)
The next issue is the Tg of the material. Our experiance is that
lower glass transition temperature laminate will produce the lifted
lands your pictures show. The last time I worked on this specific
issue the laminators all said that the higher Tg's would not make a
difference. In practice it makes a huge difference.
Finally the copper thickness. I don't know that I subscribe to this
answer but I have heard it often. When your panel hits the solder
the glass epoxy will move, quickly. If your plating is too thick it
moves, but moves much slower. The difference in the coefficient of
expansion and the speed the material is moving causes lifted
lands. Plate less and the copper will move faster.
Good luck, let us know what you find.
pete
On 10 Apr 03, at 7:15, Robert Coburn wrote:
> Hi Werner;
>
> My apologies for providing little information.
> I just became a member of TechNet yesterday and this is my first inquiry.
>
> The condition is being seen on .062, double sided boards.
> The lift being seen is both foil separation from the resin and tearing of
> the resin below the foil without the foil separating from the resin.
>
> The dwell time in HASL has been reduced to approx. 1 second with a
> temperature ramp down after HASL of about 5 minutes prior to
> post-cleaning.
> The copper plating tanks have recently been carbon treated and the
> elongation of the copper has been tested (currently 13%).
> Different laminate manufacturers have been processed and the problem
> appears regardless of laminate manufacturer.
>
> This condition is appearing on the bare board, not assembled product.
>
> Does TechNet etiquette allow me to attach a picture with my initial
> inquiry or responses?
>
> Regards,
> Rob
>
>
>
>
>
> Werner Engelmaier <[log in to unmask]>
> Sent by: TechNet <[log in to unmask]>
> 04/09/03 11:35 PM
> Please respond to "TechNet E-Mail Forum."; Please respond to Engelmaier
>
>
> To: [log in to unmask]
> cc:
> Subject: Re: [TN] TechNet E-mail forum / Lifted lands / As Received sample / Root
> causes?
>
>
> Hi Robert,
> You provide precious little info on your problem.
> When you say "lifted lands" what do you mean? Land rotation?
> How thick the PCB?
> On the basis of what have"Thermal, copper elongation and material factors
> have been removed from the equation as non-influences"?
> Is this a PTH or a PTV?
> What is the history?
> If it is a PTV, what kind of component lead is in the PTV?
> What kind of soldering processes have been used?
>
> Werner Engelmaier
> Engelmaier Associates, L.C.
> Electronic Packaging, Interconnection and Reliability Consulting
> 7 Jasmine Run
> Ormond Beach, FL 32174 USA
> Phone: 386-437-8747, Fax: 386-437-8737
> E-mail: [log in to unmask], Website: www.engelmaier.com
>
> ---------------------------------------------------
> Technet Mail List provided as a free 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/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 1.8e
> 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 Techne
t NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Dig
est
> Search the archives of previous posts at: http://listserv.ipc.org/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
> -----------------------------------------------------
>
Peter Menuez
QA Manager
Proto Circuit, Inc.
330-572-3400
[log in to unmask]
---------------------------------------------------
Technet Mail List provided as a free 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/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------
|
