You can use blind vias in the SMT pads.  There are several ways to 
     manufacture small blind vias, such as laser drilling, plasma ablation 
     and photodefined vias.  You can then use soldermask to plug only the 
     through vias.
     
     Mason Hu
     Zycon


______________________________ Reply Separator _________________________________
Subject: PLUGGED VIAS
Author:  [log in to unmask] at corp
Date:    10/14/96 10:24 AM


I have run into a problem with a board that has vias in smt pads.  We 
need all of the vias plugged, and I am told that solder mask is the best 
way to do that.  This is to ensure that a good vacuum is maintained for 
our ATE equipment.  That is the problem.  I can not have a via covered 
with solder mask on top of an smt pad.  The board house I am using says 
this is difficult for them because they have to determine which vias are 
plugged and which are not.  Anyone out there with any suggestions?
     
Thanks,
     
    Barry Darnell
(864)627-8800 Ext. 231
[log in to unmask]
CD Electronics, Inc.
Printed Circuit Board Designer
     
*************************************************************************** 
* TechNet mail list is provided as a service by IPC using SmartList v3.05 * 
*************************************************************************** 
* To unsubscribe from this list at any time, send a message to:           * 
* [log in to unmask] with <subject: unsubscribe> and no text.        * 
***************************************************************************
     

***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to:           *
* [log in to unmask] with <subject: unsubscribe> and no text.        *
***************************************************************************