George; Actually not too hard. Extending dwell in developer may help. Rinse Spray pressures are another obvious spot to play. Type of LPI will probably also have an affect. We have no trouble with residual soldermask until very high aspect ratios (greater than 10:1-12:1) or smaller than 8 mil holes. We continue to try to push that envelope too. The 2 mils finished hole tolerance isn't too bad with Immersion Au or with an OSP on Copper. Overall, your board probably won't be buildable in the far east, but it doesn't sound too bad. We build similar all the time, and there are several other shops with similar abilities. Jim Herard KBL, Product Quality Engineering IBM Microelectronics Endicott t/l 857-7026 ---------------------- Forwarded by Jim Herard/Endicott/IBM on 07/30/97 07:42 AM --------------------------- [log in to unmask] 07/29/97 09:14 AM Please respond to [log in to unmask] @ internet To: [log in to unmask] @ internet cc: Subject: Fab: soldermask capability Hello Colleagues One of my favorite 'smaller-is-better' design Engineers found a Nanionics connector which uses 30 AGW wire for thru-hole leads, and recommends a thru hole diameter of 12-16 mils. (Tight tolerance, too, huh?) Question: Has anyone had problems with soldermask being left in these small holes. The alleged failure mode is from the LPI-developer not able to develop out soldermask in these holes, due their small diameter. This is reasonable, since LPI developing likes alot of impingement. I am looking for individuals who can commiserate, and who may have worked out an alternative. Other topic we could also talk about is holding a +/- .002 hole size with solder coating; HASL?; Plate and reflow?; Ni/ Immersion Gold? Finally, who in the Board industry told Nanionics this was an 'easy' thing to do? (just kidding) George Franck Raytheon E-Systems *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************