Angelo:

Uneven oxide is ALMOST always caused by one of two causes:
1.) Dirty Copper, usually resist residues unremoved by cleaner....always have
a good alkaline cleaner as first step.

2.) Tarnish....if the panels take too long from the microetch to the oxide,
or oxide predip, tarnish may begin to form, and once tarnish begins to form,
the oxide quality turns bad.   And, the quality of the rinse water affects
how long you have before tarnish begins to form.  If there is chloride in the
rinse water, it can dramatically shorten the allowable time.

Typical allowable time will vary, depending on water quality from as low as
0ne minute, to as long as 8 minutes.

So, if things have changed, look at process cycle times, and water quality,
and preclean....

Regards,

Rudy Sedlak
RD Chemical Company

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################