durusmail: mems-talk: Re:measurement of sidewall roughness
Re:measurement of sidewall roughness
2002-02-07
Re:measurement of sidewall roughness
Jean-Bernard Pourciel
2002-02-05
Dear Vic

OK, that's it. I have now time enough to reply to your aggressive emails of
the last week in the "mems-talk" forum on the subject "measurement of
sidewall roughness".

First, I apologize to all the "mems-talk" subscribers for disturbing them by
this reply to Vic.

Vic, you don't know me; . I am the French researcher who is doing "unusable
and silly work" in Japan by using MEMS for vertical profilometry into deep
and narrow micro-holes.
I'll make a two-point reply about:
the discourteous lines which you wrote about my work
your low opinion on the French research labs and the French researchers in
Mems

To start with what you said about my work, I really must give you advice:
when you want to criticize a work, and when a paper about this work is open
on a web site, please, read it until the end and not only the first page!
Usually, and most probably you do the same, on the first page we put the
introduction, and in the introduction we write about the previous works to
give an information on the starting position of the research.. YOU HAVE READ
ONLY THE FIRST PAGE!!!! Somewhere in this page, you have found an accuracy
of 500 nm (more, you say that the "paper clearly states this limitation" of
our work.), it was about a research which was done in 1998 on
 "VibroScanning" probes.!!!

For my part, I have never said or written that our system is the best one!
You did so about the IBM SXM ! You don't know the goal of our research! As
you don't like to read the papers entirely I'm going to explain to you! We
want to measure profiles (not only roughness) inside micro-holes  with some
tens of microns in diameter and more than 1mm in depth! The IBM system
cannot do that! You said in a previous email that "it was certainly doable",
but, even if you are working with AFM since many years, you don't have done
it. We work on our project only since two years and we have results, not an
accuracy of 500nm (as you said) but +/-30nm and the precision can be
improved. This accuracy fits with the characterization requests in the field
of the inkjet printing or the making of micro-nozzles for fuel injection and
spraying into the engines. The companies want to know the inner profile of
their micro-holes; now we can give a profile, and if we can add some
information about the roughness, why not?

As a goal, we wanted to find a solution as simple as possible. Of course we
know the capabilities of AFM techniques( and "we are aware of this decade
old work by our countryman"), but I repeat that we wanted to use other
method, simpler and more fitting with our goals. We are now improving our
system and the software to render vertical strips of the inner surfaces into
micro-holes.

I agree that the IBM system (which you sell) is very efficient (you said a
resolution better than 1nm) but you cannot use it in every situation, above
all in narrow and deep micro-holes !
As a comparison, if you want to do some shopping in a very very narrow
street you don't need (and you cannot) to drive into the street with an
expensive and beautiful Rolls Royce but it is better to come in with a bike
(You see! I give you the opportunity to compare our system to a bike!).

Fabrice said that he is not aware of any major publication about this work.
For example, consult the proceedings of Transducers'01/Eurosensors XV (June
2001 in Munich) or SPIE Micro/Mems International Symposium (December 2001 in
Adelaide).

Now, about your low opinion about the French researchers and the French
labs:

I think that you are free to have any opinion about the researchers from
other countries (different than US). But I think also that there is no space
on the mems-talk forum to write this opinion as you did.

Unlike researchers from many countries, the French researchers  don't
hesitate to stay several years in a foreign country, even with a very
different culture such as Japan, to share the ideas and so to establish
strong links which can be continued after going back to their own country. It
's really a very good experience. And the aim is not, as you said so
discourteously, "to reinvent the wheel"!
The most of French researchers for Mems in Japan are young (I don't speak
for me.. I am 54 years old!) Everyone knows that in France we have great
labs for Mems (certainly with not as much funds than US or Japan) and when
these young researchers come back in the French labs, they have acquired a
lot of experience to work efficiently on Mems design.
Make enquiries and prove to me that it's wrong!

OK! Now I've got other better things to do, and I must inform you that I don't
want to continue this debate on the mems-talk forum.
But, if by chance you plan to go via Tokyo, I'll be very pleased to show you
our lab and our experimental setup. Maybe, we'll imagine that we could work
together?

This time, I hope that you have read this answer completely, from the first
line to the last one!
No hard feelings!

Scientifically yours

Jean-Bernard

PS: Franck, thanks for your prompt reply.


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Jean-Bernard POURCIEL
CNRS Senior Researcher
LIMMS/CNRS
University of Tokyo
4-6-1, Komaba,Meguro-Ku
153-8505 Tokyo

Tel : +81 3 5452 6165
Fax: +81 3 5452 6082
http://www.fujita3.iis.u-tokyo.ac.jp/~limms/
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