Hello T'Netters, I've not received a single reply from the last posting of this question, so I'd like to repeat: What document defines a low aspect via? Is there a numerical cut-off between a low aspect via and other vias? Certainly, in the 6012A document, acceptable minimum average copper thickness and absolute minimum copper thickness are defined for typical vias and low aspect vias. Is 3:1 a low aspect via? How about 4:1? Or 5:1? Any help out there? Mike Simms Trace Laboratories - Central --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------