Chris, 
Guess I don't remember it coming up.  Maybe it's a trick question right?


Anyway, I guess I would say NO.  T-50 implies a microvia is "drilled
size" of less than 0.006 inch being stated as "formation followed by a
plating operation".  So it would be treated as through hole in 6012 for
plating thickness, wrap, etc.

Make sense? 

ref. T-50
Microvia: A blind or subsequently buried hole that is <0.15 mm
[0.006 in] in diameter and formed either through laser or
mechanical drilling, wet/dry etching, photo imaging, or
conductive ink-formation followed by a plating operation.


C. D. (Don) Dupriest
Lockheed Martin Missiles and Fire Control - Dallas
Electronics Manufacturing Engineering
SME - PWB/CCA Technology Development
Ph. 972/603-7724 fax: 972/603-0410
Email: [log in to unmask]

-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Chris
Mahanna
Sent: Monday, April 14, 2008 1:48 PM
To: [log in to unmask]
Subject: [IPC-600-6012] Looking for more feedback on micro via
definition

Hello all,

For those of you who were in Vegas, this will sound familiar.  Sorry.
Due diligence forces me to ask again.

Is a 7.5mil (prior to plating) via with a 3:5 aspect ratio a "micro
via"?

Thanks!
Chris 

Chris Mahanna 
President, Technical Manager
Robisan Laboratory Inc. 
6502 E 21st Street 
Indianapolis, Indiana 46219 
317.353.6249