I have been leaving through IPC-2221 on aspect ratio but did not have any value on this information. Can some kind soul provide the answers to my questions : 1. what is the current achievable/acceptable aspect ratio for plated through hole? 2. Is there a different on the aspect ratio for PTH via? If yes, please provide. 3. What is the aspect ratio for micro via of HDI Type 1 and Type II board? 4. How about the aspect ratio for blind via on normal PTH board? A big THANK YOU to all who will be responding! Regards - Wee Mei --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------