Gabby
        See if you can get a copy of the work done by the Ultrafine
Pitch Consortium that Universal sponsored in I believe 94-95 time frame.
It had a lot of work dealing with dammed versus non dammed pads and the
effects on shorts and solderflow. I have a CD of the final report
somewhere in my files I can start looking for if you run into trouble
trying to find out about the work.
I believe the Fellow at Universal up in Binghampton NY was George
Westerby. It has been a long time ago and the names and dates are
fuzzy...
Any way hope it helps.
Russ
 ----------
From: Gabriela Bogdan
To: [log in to unmask]
Subject: [TN] solder mask between pads part2
Date: Thursday, June 25, 1998 7:06AM

Hi. TechNetters!
Thank you all for your reply!
As you see, everybody has his reasons to apply it or not.
I would like to extend my question to those who specify electroless
AU/NI on the smt pads.
Depending on artwork and plating process control of different PCB
vendors, we have seen
shadow plating on the base material and solder mask ONLY on the 16 mil
 -which is the smallest we have right now.
1.When shadow plating extends so much, is it possible that it
contributes to shorts ?
2.Without the dam, there is no shadow plating, but will we expect
difficulties in our assembly
process?
3.Do we play safe by changing the artwork for 16mil pitch GOLD FINISH?
Thank you,
Gaby

################################################################
TechNet E-Mail Forum 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://jefry.ipc.org/forum.htm) for
additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or
847-509-9700 ext.312
################################################################

################################################################
TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################