Hi John, Since I didn't see a response, I thought I'd take a stab at your questions. I'm not as familiar as others which is why I waited to respond. It's hard to be specific as so much falls into the category of "it depends." Don't you just hate that, but here goes. A) What sort of yields can be expected from COB technology? In general, I think we plan for 95 to 99 % due to process only with most around 98, but I'm just guessing here. Wire bonding only has a very high final yield rate simply because it can inspected and reworked fairly easily. B) How long would an 80 wire bond COB take to complete (on average)? Time for wire bonding only would be from 1 1/2 to 4 minutes. Factors affecting this would be complexity of design, number of reference points, setup time, and of course wire bonding equipment. The whole assembly can take anywhere from four to 15 days, depending on number of steps. Limiting factors I've seen are epoxy cure steps, device screening (burn-in, electrical test), and capacity issues. C) What are the process steps for COB? Let's see if I can get this right. Take for example a complex board with SMT, Die, heatsink, and interconnect. 1) SMT 2) DI wash 3) Plasma Clean 4) Die Mount 5) Wire Bond 6) Encapsulate or Lid attach 7) Mark 8) Heatsink Attach 9) Pin Attach 10) Final test Now, some of these steps may be interchanged. For example, if it was chip on heatsink, you would have to perform heatsink attach prior to die attach. Don't forget to add any inline electrical and visual inspection steps. D) What encapsulation material is used? Usually an epoxy formulation, but I have seen some silicones. Sometimes, there is both silicone and epoxy used to provide for greater environmental and mechanical protection. Hope this helps, Glenn http://www.maxtek.com ############################################################## 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 ##############################################################