Cecilia- Reliability of conductive adhesive joints on PWB, under environmental conditions such as humidity and thermal cycling, is a topic of great interest to me. Recently found good references on this topic. See IEEE Trans. on Components and Packaging Technologies, June 1999 Issue [Vol.22 No.2] Continuous Electrical Resistance Monitoring, Pull Strength, and Fatigue Life of Isotropically Conductive Adhesive Joints, by J. H. Constable, T. Kache, H. Teichmann, S. Mühle, and M. A. Gaynes A Reliable and Environmentally Friendly Packaging Technology--Flip-Chip Joining Using Anisotropically Conductive Adhesive, by J. Liu, A. Tolvga˚rd, J. Malmodin, and Z. Lai Full Table of Contents at: http://www.cpmt.org/past_trans/capt_toc_9906.html Johan Liu [from the second paper listed] was with IVF in Sweden for many years, and is now exclusively at Chalmers University, and has always published extensively on anisotropic (ACA) and (ICA) isotropic conductive adhesives. ICAs are what most of us use, or are considering using these days. He also edited and co-authored a recent text on conductive adhesives, "CONDUCTIVE ADHESIVES FOR ELECTRONICS PACKAGING"; see- http://www.elchempub.com/epfiles/ep35.htm One thing I'd like to see characterized in more detail is the influence of component [chip cap or resistor] terminal metallization, and the finish on the PWB mounting pads for these components. Regards, Michael Alderete Cecilia Alkhagen WROTE... ------------------------------ Date: Mon, 30 Aug 1999 17:33:33 +0200 From: "Cecilia Alkhagen (EMW)" <[log in to unmask]> Subject: Resisitivity change in conductive adhesives Hello, Here is another question related to materials in the electronic = industry...(I've got millions!) On using conductive adhesives in micro electronics we have found that = sometimes the resistivity in conductive adhesives, epoxi and silver = flakes, increases upon repeated curing/heating. A test was performed and a resistivity change was recorded upon = repeated curing. Some time later the experiment was repeated, under = exactly the same conditions as far as we know, but no change in = resistivity ocurred. Has anyone experienced the same? What can be done about it? Can it be avoided or is it a "naturally occuring" phenomena?=20 Cecilia Alkhagen ****************************************** Ericsson Microwave Systems AB Production Engineering Development Bergfotsgatan 2 S-431 84 M=F6lndal Telephone +46 31 747 0000 Direct +46 31 747 0288 Fax +46 31 747 2635 ------------------------------ ############################################################## 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 Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################