To confirm my understanding, the LPI is lifting from a metal (presumeably
Copper) surface that has had long term contact with a temporary soldermask
off?

If the above is correct, it would confirm some of our testing.   We find that
the LPI bonds mostly by chemical bonding, at least to the Copper.  And your
mask is reacting with the Copper, and forming organo-metallic residues, that
are not coming off....hence the fact that the longer the temporary mask is
on, the worse the problem.   These residues prevent the LPI from forming
chemical bonds with the surface.

To solve it?  I would consider some kind of inhibitor applied to the Copper
surface, before applying the solder stop.  Unsure if this would help.
What would definitely help would be a good chemical clean of the surface
after removal of the Solder Stop.

Hope this gives some insight.

Rudy Sedlak
RD Chemical Company

---------------------------------------------------------------------------------
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
---------------------------------------------------------------------------------