Steve, I would bet you are right about the shorting... I have seen shorting in similar conditions due to 2 conditions... 1) Contamination of the adhesive structures around the traces by the material manufacturing process and fabrication process 2) The adhesive structure is incorrect for the high temp and humidty environment...i.e. TCE is too high, adhesive is microcracking and absorbing moisture, or the adhesive is too hydroscopic... If the adhesive is the problem, you might try baking the assembly to see if this extends the MTTF... I don't know of a good way to determine if it is a contamination problem.... Paul Edwards Process/Quality Engineering [log in to unmask] Tel: 408-433-4700 FAX: 408-433-9988 Surface Art Engineering 81Bonaventura Dr. San Jose, CA 95134 DUNS: 944740570 CAGE/NCAGE: 1XZ48 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Kelly Sent: Friday, July 14, 2006 7:31 AM To: [log in to unmask] Subject: [TN] Flex Circuit Voltage Failures Good Morning, I apologize for this long e-mail but I thought it best to try and provide as much info as possible. We have a customer who is experiencing voltage failures on the following build : S/M .0007 Copper (pads layer) .008 FR-4 (Isola 410) .0007 Copper (pads layer) .001 DuPont Acrylic adhesive (bag layer) .001 DuPont FR Kapton (bag layer) 1080 pre-preg .0005 DuPont kapton .0005 DuPont Adhesive .0007 Copper (signals) .001 Kapton .0007 Copper (signals) .0005 adhesive .0005 kapton .0005 adhesive .0007 copper (signals) .001 kapton .0007 copper (signals) .0005 adhesive .0005 kapton 1080 pre-preg .001 kapton .001 adhesive .0007 copper (pads layer) .008 FR-4 .0007 copper (pads layer) S/M Finish ENIG Lines are .004-.005 and spaces .008. The part is run at 75 C , 90 % RH, with 300 volts run on line 1 , 0 on line 2 etc. Failures start to occur after approx. 48 hours and we think it is track to track. Any thoughts or suggestions would be appreciated. Steve Kelly PH: (416) 750-8433 FAX: (416) 750-0016 CELL: (416) 577-8433 --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------