Look in the IPC-SM-782, IPC-SM-840 and IPC-2221 / IPC-2222. It does not sound like the Solder Mask is your problem. 10 mils wide leaves 10 mils between lands. How thick is the stencil? What is the ratio of the paste brick to the land area? I would put my money on a process problem, paste, printing, then reflow profile, last solderability of pads or parts. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Jorge A Rodriguez Sent: Wednesday, July 19, 2000 4:07 PM To: [log in to unmask] Subject: [TN] Solder mask clearance Fellow technetters, Can someone help me to find out what's the maximum clearance on all sides of pads for a HASL board on a 20 mil pitch QFP. We are having bridging problems with this device and we are suspecting of the solder mask between the pads. Currently the PWB we are using shows 10 mils pads followed by a clearance of 2.5 mils and then 5 mils of solder mask. Also what is a normal thickness of the plating on a HASL board? Any information will be appreciated Jorge A Rodriguez Process Engineer Conexant Systems Inc ############################################################## 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 ##############################################################