GaAs or AlGaAs surface need somewhat different treatment before spin
photoresist than Si surface.
GaAs surface requires of removal of surface oxide layer before the coating.
That can be achieved by dip the whole wafer in a dilute acid follow by a
quick vac-bake then coat photoresist right away.

Chul Park
Agilent Technology

-----Original Message-----
From: [email protected]
[mailto:[email protected]]
Sent: Monday, January 28, 2002 9:01 AM
To: [email protected]
Subject: mems-talk digest, Vol 1 #169 - 13 msgs


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Today's Topics:

   1. RE: NEMS oscillators (Anatoli Olkhovets)
   2. Teflon foil. (Nathalia)
   3. RE: How to prevent the ethant from creeping along
       the interface between photoresist and semiconductor material?
(Qingwei Mo)
   4. Re: any method to measure residul stress in bonding
       membrane (Karl Cazzini)
   5. RE: electrostatic pull-in voltage for cantilever
       beam (Zhang Xuming)
   6. RE: NEMS oscillators (Zhang Xuming)
   7. RE: measurement of sidewall roughness (Franck Alexis Chollet (Asst
Prof))
   8. Wafer Dicing (Emil Jun Burgos)
   9. Statistical Process Control (SPC) (Roger Brennan)
  10. SV: [mems-talk] RE: Need 3" Si wafers (Jan Vedde)

--__--__--

Message: 1
From: "Anatoli Olkhovets" 
To: 
Subject: RE: [mems-talk] NEMS oscillators
Date: Fri, 25 Jan 2002 17:47:19 -0500
Reply-To: [email protected]

Tim,

there are several groups that work on just what you described. There is
Craighead group at Cornell U (http://www.hgc.cornell.edu/index.html) (I am a
former member of that group, now at Bell Labs), also Clark Nguyen's group at
the U of Michigan (http://www.eecs.umich.edu/~ctnguyen/), Roukes's group at
CalTech (http://www.cmp.caltech.edu/~roukes/). The devices they make are
indeed sub-micron. For example, Cornell group made wires down to 50 nm in
width, with resonating frequencies up to 400 MHz. Nguyen's group makes
electric circuits out of small resonators. As for the Q factor, you have
less air resistance, but the dominance of surface (and surface defects)
actually creates more dissipation, so higher frequency oscillators tend to
have lower Q-factors.

So when you move from MEMS to NEMS, you do get higher frequencies, higher
sensitivities, less power. But they are also more difficult to manufacture
(need E-beam litho), have lower Q, more difficult to couple to.

Anatoli.

--------------------------------------
Anatoli Olkhovets
Member of Technical Staff
Bell Laboratories, Lucent Technologies
600 Mountain Avenue
Murray Hill, NJ 07974
Tel (908) 582-3999         Fax (908) 582-6904
Email: [email protected]

> Deal all,
>
> Moving from MEMs to NEMs (from Micro to Nano, or at least sub 100
> micron) it
> would seem that moving to smaller sizes would result more sensitivity for
> sensors, higher frequency operation for oscillators, less power
> dissipation,
> less dissipative effects (higher Q factor). I am aware that there is some
> activity on developing high frequency mechanical oscillators, with strong
> applications in communication technology, but could anyone point me in the
> direction of who is doing the work?
>
> Any general comments on moving from MEMs to NEMS would also be
> appreciated.
>
> Regards
>
> Tim
>
>
>
> *****************************************************************
> Tim E. Harper                    CEO
> CMP Cientifica s.l.
> Phone +34 91 640 71 85       Fax  +34 91 640 71 86
> http://www.cmp-cientifica.com/
> _______________________________________________
> [email protected] mailing list: to unsubscribe or change your list
> options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk
> Hosted by the MEMS Exchange, providers of MEMS processing services.
> Visit us at http://www.mems-exchange.org/

--__--__--

Message: 2
From: "Nathalia" 
To: 
Date: Fri, 25 Jan 2002 15:34:27 -0800
Subject: [mems-talk] Teflon foil.
Reply-To: [email protected]

Hi Heiko,

depending on the teflon you're looking for, Durafilm might have it.
Write me an email if you need more info/their webpage.
([email protected]).

Regards,
Nathalia
http://transducers.stanford.edu

--__--__--

Message: 3
From: "Qingwei Mo" 
To: 
Subject: RE: [mems-talk] How to prevent the ethant from creeping along
  the interface between photoresist and semiconductor material?
Date: Fri, 25 Jan 2002 17:46:05 -0800
Reply-To: [email protected]

Hi, Thank you, Mike.
I use diluted HCL(2:1), and the AlGaAs contains 80%Al.
I need to undercut 8um. So, the 0.1um/min etch rate will take 80mins, which
may be too long for the photoresist.
I will try baking the wafer before spin and HCl(1:1) to see whether there is
any improvements.

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of Michael Yakimov
Sent: Friday, January 25, 2002 8:37 AM
To: [email protected]
Subject: RE: [mems-talk] How to prevent the ethant from creeping along
the interface between photoresist and semiconductor material?


What is the concentration of HCl? composition of AlGaAs?
from our experience, we found that photoresist may haveadhesion problems
with concentrated  (36%) HCl, baking the wafer before spin  and photoresist
hard bake before etrching slightly improve the situation.. Diluted HCL (1:1)
has no adhesion problems- but I'm not sure about the etch rate.
 For higher Al content you may try to use diluted BHF. I don't have the
reference right now, but for diluted BHF ( BHF(6:1) :DI = 1:20 the etch rate
for 85%Al is about 0.1 um/min, and it has no problems with photoresist
adhesion

Mike

> -----Original Message-----
> From: Qingwei Mo [SMTP:[email protected]]
> Sent: Thursday, January 24, 2002 8:14 PM
> To:   Mems-Talk
> Subject:      [mems-talk] How to prevent the ethant from creeping along
> the interface between photoresist and semiconductor material?
>
> Hi, I am trying to etch the AlGaAs under a GaAs layer using HCl. The
> AlGaAs
> is exposed to the etchant at the sidewall of a trech. To protect the most
> part of the trench, I covered the whole thing with photoresist AZ4330.
> There
> is only a small opening left to let the echant in. However, what I found
> is,
> somehow, the etchant creeped along the interface between the photoresist
> and
> the sidewall. And etch away the material they are not supposed to. I have
> tried both wet etch are RIE to make the sidewall, it doesn't change much.
> Anyone has any idea, or similar experience? Is there something wrong with
> the sidewall or the recipe of the photoresist?
>
> Thanks a lot for your help
>
> Qingwei
>
> **********************************************************
> Mo, Qingwei                                              *
> Phone:(512)-476-4746 (H)                                 *
>       (512)-471-7917 (O)                                 *
> Fax:  (512)-471-8575 (O)                                 *
> Email: [email protected], [email protected]              *
>                                                          *
> /------   \ | | /  ---------------------\                *
> |          -----       | |Microelectronic Research Center*
> |        [  @ @  ]      | Electrical and Computer Eng.   *
> \--oOOO-----(_)----OO0o-| University of Texas at Austin  *
> **********************************************************
> _______________________________________________
> [email protected] mailing list: to unsubscribe or change your list
> options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk
> Hosted by the MEMS Exchange, providers of MEMS processing services.
> Visit us at http://www.mems-exchange.org/
_______________________________________________
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options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk
Hosted by the MEMS Exchange, providers of MEMS processing services.
Visit us at http://www.mems-exchange.org/

--__--__--

Message: 4
From: "Karl Cazzini" 
To: 
Subject: Re: [mems-talk] any method to measure residul stress in bonding
  membrane
Date: Fri, 25 Jan 2002 20:00:02 -0500
Reply-To: [email protected]

The easiest way to observe areas of possible stress in such a composite
system, is to illuminate with a polarised light source (s or p polarised
HeNe). Illuminate at an angle of about 30 degress to the surface normal, and
view the reflected light through a polariser. By orienting the polariser,
you will see modulations in the reflected light intensity, indicative of
residual stress in the system.

K. Cazzini (Ph.D)


----- Original Message -----
From: "li shifeng" 
To: 
Sent: Friday, January 25, 2002 9:35 PM
Subject: [mems-talk] any method to measure residul stress in bonding
membrane


> Hi, friendsI am interest to measure the residual stress in glass membrane
> after Si-Glass bonding. As i know, eventhough thermal coefficient is
> pretty closed between silicon and Preyx7740, there is some stress left
> after bonding. The residual stress affects membrane vibriation
> performance somehow.Anyone has done similar experiment before or has the
> same idea? maybe you can share some information. any information
> will appreciated. thanksshifeng
>
> ------------------------------------------------------------------------
>
> Chat with friends online, try MSN Messenger: Click Here
> _______________________________________________
> [email protected] mailing list: to unsubscribe or change your list
> options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk
> Hosted by the MEMS Exchange, providers of MEMS processing services.
> Visit us at http://www.mems-exchange.org/

--__--__--

Message: 5
Subject: RE: [mems-talk] electrostatic pull-in voltage for cantilever
  beam
Date: Sat, 26 Jan 2002 09:52:40 +0800
From: "Zhang Xuming" 
To: 
Reply-To: [email protected]

Dear Leow Cheah Wei:

Below are some papers discussing the pull-in phenomenon. Not directly for
cantilever beam, but they may be helpful.

[1]     X. M. Zhang, F. S. Chau, C. Quan, Y. L. Lam and A. Q. Liu, A study
of the
static characteristics of a torsional micromirror, Sensors and Actuators A:
Physical 90 (1-2) (2001) pp. 73-81.
[2]     H. Toshiyoshi and H. Fujita, Electrostatic micro torsion mirrors for
an
optical switch matrix, J. Microelectromechanical Systems, 5(4) (1996)
231-237.
[3]     O. Degani, E. Socher, A. Lipson, T. Leitner, D.J. Setter, S. Kaldor,
and
Y. Nemirovsky, Pull-in study of an electrostatic torsion microactuator, J.
Microelectromechanical Systems, 7(4) (1998) 373-379.
[4]     J. B|hler, J. Funk, J.G. Korvink, F-P Steiner, P.M. Sarro, and H.
Baltes,
Electrostatic aluminum micromirrors using double-pass metalliztion, J.
Microelectromechanical Systems, 6(2) (1997) 126-135.

Regarding to bilaye cantilever beam, a paper from M.C. Wu's group may be
useful for you.

[1]     R.T. Chen, H. Nguyen, and M.C. Wu. A low voltage micromachined
optical
switch by stress-induced bending. In Proceedings of Twelfth IEEE
International
Conference on Micro Electro Mechanical Systems (MEMS 99), Florida USA, pp.
424-428, 1999.

Rgds,

Zhang Xuming

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of LEOW Cheah Wei
Sent: Friday, January 25, 2002 7:41 PM
To: [email protected]
Subject: [mems-talk] electrostatic pull-in voltage for cantilever beam


Dear everybody,

       can somebody post or point to some link on measured data for pull-in
voltage of a
1) cantilever beam
2) bilayer cantilver beam (e.g. poly2 with metal from MUMPS and it is curved
)
3) related structure
     i'm interested in simulating/modeling the pull in voltage Vs beam
length. The data will be very useful in verifying the result.

thank you

LEOW Cheah Wei
master student
Universiti Teknologi Malaysia
http://www.geocities.com/cheah_wei

[demime 0.98e removed an attachment of type image/gif]
_______________________________________________
[email protected] mailing list: to unsubscribe or change your list
options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk
Hosted by the MEMS Exchange, providers of MEMS processing services.
Visit us at http://www.mems-exchange.org/

--__--__--

Message: 6
Subject: RE: [mems-talk] NEMS oscillators
Date: Sat, 26 Jan 2002 10:07:36 +0800
From: "Zhang Xuming" 
To: 
Reply-To: [email protected]

HI, Tim:

Some useful papers discussing NEMS are as follows. Hope they can start your
route to do literature survey.
[1] H.G. Craighead, Naoelectromechnaical systems, Science, vol. 290, 24 Nov
2000, pp. 1532-1535.
[2] S.R. Quake and A. Scherer, From Micro- to Nanofabrication with soft
materials, Science, vol. 290, 24 Nov 2000, pp. 1536-1539.
[3] M.L. Roukes, Nanoelectromechanical systems, Solid-State Sensor and
Actuator Workshop, Hilton Head Island, South Carolina, June 4-8, 2000, pp.
367-376.

Regards,

Zhang Xuming


-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of Tim E. Harper
Sent: Saturday, January 26, 2002 1:15 AM
To: '[email protected]'
Subject: [mems-talk] NEMS oscillators


Deal all,

Moving from MEMs to NEMs (from Micro to Nano, or at least sub 100 micron) it
would seem that moving to smaller sizes would result more sensitivity for
sensors, higher frequency operation for oscillators, less power dissipation,
less dissipative effects (higher Q factor). I am aware that there is some
activity on developing high frequency mechanical oscillators, with strong
applications in communication technology, but could anyone point me in the
direction of who is doing the work?

Any general comments on moving from MEMs to NEMS would also be appreciated.

Regards

Tim



*****************************************************************
Tim E. Harper                    CEO
CMP Cientifica s.l.
Phone +34 91 640 71 85       Fax  +34 91 640 71 86
http://www.cmp-cientifica.com/
_______________________________________________
[email protected] mailing list: to unsubscribe or change your list
options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk
Hosted by the MEMS Exchange, providers of MEMS processing services.
Visit us at http://www.mems-exchange.org/

--__--__--

Message: 7
Subject: RE: [mems-talk] measurement of sidewall roughness
Date: Sat, 26 Jan 2002 11:24:36 +0800
From: "Franck Alexis Chollet (Asst Prof)" 
To: 
Reply-To: [email protected]

Hi Vic,
the probe developed allows, in principle, to measure sidewall roughness in
hole... up to 1mm deep, and about 25um diameter. I don't believe the AFM
probe
of IBM can do that... but, OK, I never used it :-)
Moreover, the depth profile resolution seems to be about 70nm and not 500nm.
Thus the tool developed here has certainly a use, but, it is true that it
may
not be what the original poster wanted and IBM probe may be the best
suited...
for his application.

BTW, on a historical note, the first idea of the probe comes from the team
of
Professor Masuzawa at Tokyo University... a long time ago (more than a
decade...) - at a time where when I saw MEMS written I just thought it was
misspelled for 'nems' (which is how the Chinese spring rolls are called in
French :-)

Happy Chinese new year to everyone!
Franck
PS: who cares about the citizenship of inventors? Intelligence has no
boundary!

"-----Original Message-----
"From: Vic Kley [mailto:[email protected]]
"Sent: Friday, 25 January, 2002 16:12
"To: [email protected]
"Subject: Re: [mems-talk] measurement of sidewall roughness
"
"
"Fabrice and Emer
"
"The first link you provided is bogus. The proper link to the paper of
"interest is http://www.fujita3.iis.u-tokyo.ac.jp/~limms/
"
"However the paper clearly states that the resolution limit of
"their reported
"method is presently 500nm! This is unusable and again it is silly to
"continue looking when in fact the IBM SXM series sidewall profiling AFM
"already resolves better then 1nm and has been doing so for a
"decade.  These
"microscopes have been sold and are in use in Japan where
"apparently they
"very much like to reinvent the wheel in collaboration with the
"French. The
"funny thing is the IBM scientist who invented the sidewall
"profiling AFM
"about 13 years ago is a Frenchman!
"
"Vic Kley
"_______________________________________________
"[email protected] mailing list: to unsubscribe or change your list
"options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk
"Hosted by the MEMS Exchange, providers of MEMS processing services.
"Visit us at http://www.mems-exchange.org/
"

--__--__--

Message: 8
Date: Sun, 27 Jan 2002 14:45:09 -0800 (PST)
From: Emil Jun Burgos 
To: [email protected]
Subject: [mems-talk] Wafer Dicing
Reply-To: [email protected]

Hello,

Can somebody point me any technical reference for
wafer (silicon) dicing (wet process). I'm currently
working in improving the yield of our product which is
attribute to wafer dicing.

Thank you very much.

Emil Burgos
Senior Process/Product Development Engineer
Great stuff seeking new owners in Yahoo! Auctions!
http://auctions.yahoo.com

--__--__--

Message: 9
From: Roger Brennan 
To: "[email protected]" 
Date: Sun, 27 Jan 2002 19:49:39 -0800
Subject: [mems-talk] Statistical Process Control (SPC)
Reply-To: [email protected]

Has anyone found a Statistical Process Control (SPC) book or software
program they like?
I need to set up something for a small fab and track the usual things: sheet
rho, thicknesses, etch depths, critical dimensions, etc.

Thanks very much,

Roger Brennan
Home:
1403 Forrestal Avenue
San Jose, CA 95110
(408)453-0711 (telephone)
(408)573-9407 (fax)
[email protected]

Work:
Endevco
355 N. Pastoria Ave.
Sunnyvale, CA 94085
408-739-3533 ext 204
[email protected]

--__--__--

Message: 10
From: Jan Vedde 
To: "'[email protected]'" 
Subject: SV: [mems-talk] RE: Need 3" Si wafers
Date: Mon, 28 Jan 2002 16:43:09 +0100
Reply-To: [email protected]

Dear QF

You might contact our sales department ([email protected]) , or even look at
our web page, as we might have some wafers ready on stock.

Best reagards,

Jan Vedde
Topsil Semiconductor Materials
FZ silicon crystal grower and wafer manufacture.

www.topsil.com


 -----Oprindelig meddelelse-----
Fra:    Qifa Zhou [mailto:[email protected]]
Sendt:  23. januar 2002 02:53
Til:    [email protected]
Emne:   [mems-talk] RE: Need 3" Si wafers

Hi

   We need 3" Silicon wafers with one side polish, thickness is about 300um.
 Would you tell me some information?

    Thanks in advance!

    QF Zhou
_______________________________________________
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Hosted by the MEMS Exchange, providers of MEMS processing services.
Visit us at http://www.mems-exchange.org/


--__--__--

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End of mems-talk Digest