Hello Technetters, I have a question about layer stack-ups. Some time ago a respected contributor to this forum presented us with some valuable information in the form of a specification he developed. In this specification, under the title, MASTER DRAWING NOTES 1.0 Laminate, Core and Prepreg Material, section 1.9 states,"There shall be no 7628 glass style prepreg used facing copper. If required, single ply or multi-ply 7628 core material may be used. If used as prepreg, 7628 only may be used between two other more resin rich glass styles." My question is what does this mean to the stack-up? Why should you not use 7628 facing copper? Does it have to do with the amount of resin not present in 7628 and may not bond to the copper sufficiently? What should be used? and Why? I hope this question is not too imposing. Thank you in advance. Tom Burek, CID+ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------