Nicolas, Are the shorts consistently on two parallel sides closest to the conveyor rails. If so, the part and paste are probably sliding to one side or another on the domed pads that HASL causes. This usually happens during the soak zone in the oven when the paste becomes less viscous. We have found (like many other have found) that using a flat surface finish will significantly reduce shorts on fine pitch compared with using HASL. If you are at 38 dpmo (I assume for shorts only?) with HASL, I think you are doing pretty good. To do better than that, you will have to use a flat surface finish. Thanks Ryan Grant Advanced Technology Engineer MCMS (208) 898-1145 [log in to unmask] > -----Original Message----- > From: Nicolas Ortiz [SMTP:[log in to unmask]] > Sent: Monday, February 05, 2001 1:45 PM > To: [log in to unmask] > Subject: [TN] QFP144 solder bridging > > Currently we are experiencing solder bridging on a 0.5mm pitch, LQFP, > 144 > leads. I already reviewed the stencil design, screen printer parameters > and > reflow profile. Everything is OK. We have HASL boards. Our current process > outputs 38 dpmo's. My concern is if I reduce more the apertures, I have > the > risk to have solder open or insufficient solder, instead of bridging. Does > anybody has some input? What dpmo's do you have? > > -------------------------------------------------------------------------- > ------- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d > 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 delivery of Technet send the following message: SET > Technet NOMAIL > Search previous postings at: www.ipc.org > On-Line Resources & Databases > > E-mail Archives > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for > additional > information, or 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 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------