First of all, the overall board thickness: consult your PCB manufacturer on his aspect ration limit: it can be anywhere between 1:7 to 1:14. The minimal hole diameter should not be less than the PCB depth divided by the aspect ration. After this, consider the current capacity of every via: 0.01 mils via can carry 0.4 A; 0.012" via can carry 0.5A. Third, consider signal integrity and skin effect. The difference should not be big in most cases, but RF boards and very high frequency digital boards may be affected. Regards Ofer Cohen Quality Assurance Manager Seabridge Ltd. -----Original Message----- From: Genny Gibbard [mailto:[log in to unmask]] Sent: Wednesday, March 05, 2003 18:42 To: [log in to unmask] Subject: [TN] info requested We have an 8 layer board that we need to turn into a 10 layer board. We have adjusted our layer stackup to accommodate the extra layers without any significant change in overall thickness, but we are still having trouble fitting everything we need onto the layout. What are the implications of going from a minimum .012" via to a 0.010" via? What do we need to take into consideration? What things might be critical to spec to the board fab house? Genny Gibbard ( mailto:[log in to unmask] <mailto:[log in to unmask]> ) --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------