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March 2000

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Subject:
From:
Ryan Grant <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 16 Mar 2000 13:05:23 -0700
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Jethro,
        I have tried the method that KK Chin spoke of and had some trouble.
I didn't find it as easy as it sounded.

        First of all, not clearly mentioned is that the "easy" migration
will only occur with exposed metal.  So scrape off the solder masking where
ever you intend to place the drop of water.  Also, Gold doesn't migrate
easily, so make sure the board is a HASL (as mentioned by Dr William) or
OSP.  Second, the hydrolysising (is that a word?) water obscures being able
to see anything.  Third, I tried to measure the resistance between the
traces so I knew when I had a bridge.  I found the water would conduct (of
course), but conduction stopped when the water was completely evaporated.
Evaporating a drop of water doesn't take very long.  So I had to continually
add water.  Finally, in my impatience, I found that I had to place a tiny
drop of flux on the spot to get thing started.  (Maybe my boards may were
too clean to get quick results.)

        However, when every works, it works as advertised.  I found that I
could bridge pads or traces quite easily and quickly.  I just had to wait
for the foaming water to disappear and monitor the ammeter to verify
conduction still existed.

Da tater faarma in Idaho

> -----Original Message-----
> From: Stephen R. Gregory [SMTP:[log in to unmask]]
> Sent: Thursday, March 16, 2000 11:49 AM
> To:   [log in to unmask]
> Subject:      [TN] Electromigration demonstration...
>
> How the heck are yew good ol' boys doin'?
>
> (Spitoooie!!)...'scuse me thar...hadda get rid of my chew, cain't talk
> with a
> mouthful of terbacky...(hitchin' my bib overalls up)
>
> Anyhoo, a while back, some good ol' boy posted a simple way to actually
> show
> electromigration (fancy word for us country boys ain't it) in
> progress...you
> could actually see it happening. Something about using an overhead
> projector
> and a 9-volt battery...or something like that.
>
> Does anybody remember that? I need some way to graphically show this
> phenomena  happening...('nuther fancy word huh?...phenomena...)
>
> YEEEE-HAW!!!
> (that's good ol' boy talk for thanks a lot!)
>
> -Steve "Jethro" Gregory- (GRIN)
>
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