Craig It depends on the definition of first pass yields. I've heard and seen it defined many ways. You can report a first pass yield through an imaging sequence (IL and OL) where you're looking at the amount of product produced with no defects (opens, shorts, etc). At electrical test, I've seen it reported on a piece-by-piece basis or a lot-by-lot basis. I've seen the same metrics at a Final Audit operation, also, measuring escapes from previous processes. Sometimes, first-pass will refer to the first-time build of part. Can you provide a clearer definition of "first-pass"? Otherwise it's hard to assess if 50-75% is "typical". ---------- From: Craig Patterson [SMTP:[log in to unmask]] Sent: Friday, August 27, 1999 3:15 AM To: [log in to unmask] Subject: [TN] First Pass Yields Recently our bare board manufacturer indicated that his first pass yields from his electrical test for our six layer board (FR4, couple of BGA, some 20mil QFPs, 7" x 11") was about 70%. We were concerned that this may mean his process is not under control. He said that 50 to 75% first pass yield was typical in the industry. The failures were for various reasons from opens to mask on pads. Does anyone have an opinion regarding 75% reflecting the first pass yield as a benchmark of the board fab industry? ############################################################## 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 ##############################################################