1 mil, technically, is not breakout. Back in the good old days with H-P
(1970 something), their specification clearly required a 1 mil annular ring
throughout the MLB structure. This was reasoned based on minimum hole wall
plating. In other words it was, and is, not possible to have breakout with
that much plating in the hole. Something to consider along with all that
goes with it as minimum ductility and plating quality, etc.

Earl Moon
----- Original Message -----
From: Ken Patel <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, October 14, 1999 1:00 PM
Subject: [TN] Risk involved in accepting inner layer misregistration


> What are the consequences of accepting board with inner layer
> misregistration (90 degree break out)? This misregistration occurred at 1
> mil micro-BGA location.
>
> We have heard that: There are no reliability issues with breakout from
inner
> layer via's and that the industry may be moving away from this
requirement.
> Is it true? Currently, IPC-600 Class3 calls out for .001" annular ring.
>
> re,
> ken patel
> ______________________________________________________
> Ken Patel                       Phone:  (408) 490-6804
> 1708 McCarthy Blvd.             Fax:    (408) 490-6859
> Milpitas, CA 95035              Beeper: (888) 769-1808
>
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