Werner, What about tented vias using LPISM. And...is this done by flooding using a dot pattern for the vias only? We typically tent using DFSM however, at times there are requirements for LPI. TIA, Rick Howieson http://www.gt-corp.com >-----Original Message----- >From: Werner Engelmaier [SMTP:[log in to unmask]] >Sent: Thursday, June 29, 2000 7:17 AM >To: [log in to unmask] >Subject: Re: [TN] Filled via holes > >Hi Ruby, >Yes, there are some concerns about PTVs partially filled with solder. The >transition from solder-filled to non-solder-filled produces a stress riser in >the Cu PTV barrel walls. This is of no practical concern for applications for >which the thermal cyclic environment is not severe; for severe environments, >e.g., automotive, military, some satellites, this stress riser can be >enoughto cause premature failure. > >Werner Engelmaier >Engelmaier Associates, L.C. >Electronic Packaging, Interconnection and Reliability Consulting >7 Jasmine Run >Ormond Beach, FL 32174 USA >Phone: 904-437-8747, Fax: 904-437-8737 >E-mail: [log in to unmask], Website: www.engelmaier.com > >In a message dated 6/28/00 11:19:14, [log in to unmask] writes: >>Hello all: >>We try to fully or partially fill the via holes (<0.025" diameter) with >>solder due to the process. I'm wondering that if there are some concerns >>(such as fatigue). >>Any information are very welcome. Thanks a lot! >>R.H. > >############################################################## >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 >############################################################## ############################################################## 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 ##############################################################