Alain - Is the defect area isolated to the solder side of the board or is it on both sides? The mask manufacturers can probably provide you information on the compatibility of their masks with your process chemistries (flux and whatever else). This generally results in an appearance on the surface of the board that the mask has been partially dissolved and partially peeled. I would suggest a couple of quick phone calls to the mask suppliers tech support people for this information. When you use the words "peeling" and "blistering" I am more suspicious of there being a surface contaminant present on the boards at the time of mask application. This is an item the board fab house will have to isolate and deal with. Some of the higher capability test labs may also be able to assist in this area. IPC-SM-840 contains a quick cure test, using a dab of methylene chloride, as I recall. This takes just a matter of minutes to perform and can be done safely by any competent chemist. (Methylene chloride is quite unfriendly.) What it comes down to first is to isolate the cause. Regards - Kelly -----Original Message----- From: Alain Mathieu <[log in to unmask]> To: [log in to unmask] <[log in to unmask]> Date: Wednesday, December 15, 1999 3:52 PM Subject: [TN] Soldermask peeling and blistering Hi TechNetters. We are a OEM that manufactures Hi-frequency products ( 5Mhz to 1Ghz range) and therefore we use pcb (bare board) with big ground planes on both sides. all our boards are FR-4 with solderMask over bare copper. When we go thru the wave soldering process we experiment blistering and peeling offon the ground plane. We use Alpha No-Clean 26F flux , preheat top side at 230oF-240oF, bottom side 300-320oF and a dwell time of 2.4-2.6 sec. Solder Bath temp is 480oF. In the past the pcb mfr was using a different Soldermask but now he uses 2 brands with approximately the same results : Epic #200 and Entone #3242. The pcb Mfr was suspecting a problem with the curing, the thickness or a contamination before soldermask application that could explain Is there any one who had the same or similar problem? Any help on how to resolve this would be greatly appreciated. Alain Mathieu Electroline Equipment Inc. [log in to unmask] ############################################################## 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 ############################################################## ############################################################## 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 ##############################################################