We do boards every day that are 3 and 3 with microvias in pad. The board shops completely fill the hole with copper and then plate over it. They then planerize the copper so the pad is flat. I think it's pretty standard nowadays. We simply add a note to the fab drawing to plate the microvia closed and to "repad" so the surface is flat. Douglas G. Stanley PC Board Designer, Sr. Staff Broadcom Corporation <outbind://49/www.broadcom.com> - Irvine, CA dstanley@xxxxxxxxxxxx (949) 926-5889 ________________________________ From: icu-pcb-forum-bounce@xxxxxxxxxxxxx [mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of O Migs Sent: Monday, May 19, 2008 9:58 AM To: icu-pcb-forum@xxxxxxxxxxxxx Subject: [PCB_FORUM] copper filling of micro vias. Hi All, Does anyone know the requirements to copper fill or epoxy fill a microvia? microvia is via in pad. Is there an alternative? I have a design that requires a fanout of 3.5 mil trace and 3mil airgap out of a finepitch bga. -oscar ____________________________________________________ oscar miguelino | lead pcb engineer | OQO, inc. 583 shotwell street | san francisco, ca 94110 (this message constitutes confidential information proprietary to OQO, Inc.)