Hi, I don't fab bare PCB and I know little about the processes. I have a customer that is a little more "Quality Conscious" so I figured I would ask around about a few things. Most of what I do is prototype related so I started asking question at various proto shops. I could not get very good answers about Desmear and Etch back processes. In fact, it almost sounds like some board houses do not have desmear processes. So, 3 Questions: 1. Is no Desmear possible? Is the copper contact area on interlayer connections sufficiently clean to where reliable interlayer connections can be made without a desmear process? 2. Plasma etch back. Sounds like this is a specialized and highly improved way for treating holes so plated through barrels make good interlayer connections. How Much Better is it? Cost? 3. Drill to Copper spacing is important as copper wicks into glass weave spaces. Seems like my existing houses demand 12 mil. Some new places say "We can do 10mil". If I am assuming generic FR4 (it that exists) then how can someone just kiss away 2 mils out of 12? Should I disregard anyone with such a light approach to rules? I assume they are using the same drill bits, material and copper plating techniques. Is that a reasonable approach? The board in question is 5/5 rules, 8 layer, 8 mil via in 18 mil pad. Material is .062 FR4 or Equiv. Thanks, Bob K. ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 16.0 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------