On Sat, 1 Feb 2014 20:59:27 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Sat, 1 Feb 2014 15:33:35 -0500, "Jim Wilkins"
wrote:

"Ignoramus23944" wrote in
message ...
On 2014-02-01, Larry Jaques
wrote:

http://tinyurl.com/n83bc5q

ME WANT!


Looks great. I keep wondering how it works exactly, why does it
remove
paint and dirt, but not underlaying material.

Good question. I tried to learn how to use an excimer laser to dig
into an integrated circuit but never got the hang of it. I couldn't
completely sever a metallization trace on an upper layer without
gouging into the one below it.

What kind of power control did you have over the laser beam?

And was the color of the PCB somewhat responsible for the problem in
control? I know some color bandwidths absorb more of certain
types/spectrums of lasers. Was eximer the proper color, or just the
only one they had for you to use to do the job? Which gas/color?

Tell us more, por favor!

The ICs were still on the wafer. There were 3 wavelengths and a pulse
timing control. At that point I didn't understand integrated circuit
construction very well and was unsure what I was seeing anyway.

That explains your results pretty well. What was under the
traces, a more volatile substrate than the trace itself?

Wasn't that in the Bible?
"Know Thine Enemy, iffen ya wanna lase it correctly!"

--
I have the consolation of having added nothing to my private fortune during
my public service, and of retiring with hands clean as they are empty.
-- Thomas Jefferson, letter to Count Diodati, 1807

Too bad -none- of the current CONgresscritters are willing to do that. -LJ