Hi Mei,

Have you used a chain saw?  I've been investigating thousands of vias, and
I think I'm right when I say that you can't get reliable and useful
information if you don't polish correctly. Start with grit 600 for a few
seconds, then 1200, 2500 and 4000.  Use rotating sample holders to avoid
smearing of copper. After polishing, a light dip in a copper etchant and
then DI rinse. Yeah, it's a boring job, but you will find that  the
analysis becomes more interesting. AND.....read the below report of Paul
Reid (he may see this, hope he won't accuse me for copyright trespassing).
See the difference between the poor prepared samples and the correctly
prepared ones. Read the whole paper and you will learn LOTS!

Good Luck!

Inge




On 9 March 2012 13:25, Steve Gregory <[log in to unmask]> wrote:

> Hi Wee Mei!
>
>
>
> I have your pictures posted:
>
>
>
> http://stevezeva.homestead.com/first_microvia__1-2_.jpg
>
>
>
> http://stevezeva.homestead.com/2nd_microvia__3-4_.jpg
>
>
>
> http://stevezeva.homestead.com/microvia-1__9-10_.jpg
>
>
>
> http://stevezeva.homestead.com/microvia-2__9-10_.jpg
>
>
>
> http://stevezeva.homestead.com/buried_via.jpg
>
>
>
> Maybe some Technetters can steer you in the right direction….
>
>
>
> Steve
>
>
>
>
>
> From: Lum Wee Mei <mailto:[log in to unmask]>
>
> Sent: Thursday, March 08, 2012 7:04 PM
>
> To: Steve Gregory <mailto:[log in to unmask]>
>
> Subject: HDI PCB - micro-via
>
>
>
> Steve,
>
>
>
> I have never inspected any HDI PCBs before and was asked to perform
> inspection to them in accordance to IPC-A-600 and if necessary IPC-6012. I
> have no idea what I am looking for as I stare at those pictures which I
> randomly took from two of the cross-section buttons. I flipped through the
> whole IPC-A-600 and 6012 but not able to see any images/pictures that
> correspond to what I see. Also am I suppose to use 6012 or 6016 to assist
> in the inspection criteria? I am totally lost.
>
>
>
> Kindly post the pictures to TechNet so that some kind souls can help me
> out of this dark tunnel. J
>
>
>
> Thanks and regards,
>
> ~wee mei~
>
>
> DSO 40th Anniversary – Celebrating 40 years of Serious Fun. 1972 – 2012
>
>
> ______________________________________________________________________
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