Done thousands of these perimiter/super BGA's and found one solution using SRT 1000 and up machines. After tremendous frustration, raised the "pro" nozzle 80 to 100 mils off board surface, using paste flux, and eliminated problem forever. Sure! Talk to "Big Ernie" and brother about what we did at HP a couple of years ago. Had to thermally insulate close proximity devices using ceramic in some cases and Kapton tape in lesser affected areas. This worked so well, provided other problems as dogbones at right angles and exposed dogbone traces, several places at which I worked gave me a big hug, uhg! Another thing, for us at Cray, etc. - we had the luxury/need to remove heat sinks and go from there. Also used micro stencils taped to board surface using microscope when applying solder paste though hardly ever did after achieving success with paste flux unless using hard balls. So much more. Wish I could remember. --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------