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Date: | Thu, 4 Nov 2004 18:43:17 -0500 |
Content-Type: | text/plain |
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The void seems to be in the center of the hole and circular. This is
normally caused by air entrapment during the electro copper process after
drilling. However, most of the time the voiding due to these is larger so it
is possible that there was a thermal cycle was performed prior to tin and
the board expanded and fractured. The picture is not that clear. I do not
see a lot of roughness due to drilling so I would assume that it is due to
air entrapment and I would ask the supplier why it was not caught during
electrical test
----- Original Message -----
From: "Al Onderick" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, November 04, 2004 5:55 PM
Subject: [TN] Via hole failures (with pictures)
>I have a couple of boards that have failed at a customer site. After
> testing, a via was identified as open. The following link is a picture of
> the cross section.
>
> http://www.tier1gear.com/temp/via_crack.jpg
>
> The board was .062, the via .010 and the surface finish immersion white
> tin.
>
> I would appreciate any insight into what may cause a failure like this.
>
> Al Onderick
> National Instruments
>
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