On Fri, 22 May 2020 16:54:20 +0100, Larry Brophy <[log in to unmask]> wrote:
>
>Sorry I have another question and it is again to do with what you have said
>, it is a conflict between the two specifications.
>We need to use a micro BGA.  Based on our PCB manufactures capabilities in
>the BGA area we need to use a blind via drilled at 6mil with a 14mil pad to
>guarantee a 2mil annular ring.
>But IPC-2221 states that the smallest blind via is 8 mil.  Table 9-4.  This
>is just another design guide v IPC-6012 issue?

I thought Table 9-4 referred to the minimum mechanically DRILLED hole size, 
(laser can be smaller diameter?)
but after reviewing the document, it does not seem clear to me.
(good question, but I only have the 2221C Working Draft OCT2013 to look at right now)