dear associates!
all the mems group.
we are the system integrators for different applcations on mems.

we are at job now to;

1. devise an electonics signal conditioning circuit for mems sensor  with output
of 5pf + - femto pf sensitivity.
2. make the measurements of incremental pf on the sensor.

we understand that  a synchronous demodulation technique is needed so as to
increase the noise immunity.

we welcome any suggestions, equipment available, procedures.
regards
rpsoni
[email protected]


  ----- Original Message -----
  From: [email protected]
  To: [email protected]
  Sent: Monday, August 16, 2004 9:31 PM
  Subject: MEMS-talk Digest, Vol 22, Issue 16


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  Today's Topics:

     1. Re: refractive index measurement of thick films (Kamal Yadav)
     2. Piezoelectric Beam Simulation by using Ansys (Siripon Sukuabol)
     3. Removal of reflowed AZ resist (Erik Jung)
     4. Double depth SU-8 (Matthew Davies)


  ----------------------------------------------------------------------

  Message: 1
  Date: Sun, 15 Aug 2004 12:48:11 -0500
  From: Kamal Yadav 
  Subject: Re: [mems-talk] refractive index measurement of thick films
  To: [email protected], General MEMS discussion 
  Message-ID: <[email protected]>
  Content-Type: text/plain; charset=US-ASCII

  Hi,

  I am a optics student. Brewster's angle measurement is also a good
  reliable technique in measuring the index. I have done it very
  recently. At brewster's angle your reflected power goes to almost
  zero. Input light should be TM polarized i.e horizontle polarized.

  regards,
  kamal

  On Sat, 14 Aug 2004 21:22:45 -0400, sxy154  wrote:
  > Hello Xianling
  > You might want to try prism coupling technique to measure the refractive
  > index of film. The basic assumption of this method is you already know exact
  > thickness of film. Even thought, this technique is widely used for thin film
  > rather than thick film, I don't see any restriction in thickness range.
  >
  > Good Luck
  >
  > Sung
  >
  >
  >
  > -----Original Message-----
  > From: X Chen [mailto:[email protected]]
  > Sent: Friday, August 13, 2004 7:12 PM
  > To: [email protected]
  > Subject: [mems-talk] refractive index measurement of thick films
  >
  > Hello MEMS talkers,
  >
  > Does anyone know a way to measure refractive index of thick films? I used
  > spectrophotometer to measure the VIS spectral transmission of 50 micron
  > SU-8 on Borofloat wafer. However, the transmittance modulation is just too
  > weak for reliable index fitting. With a large film thickness, light
  > coherence is lost due to finite bandwidth and surface vaiation. Reducing
  > film thickness to a few microns using SU-8 thinner will solve this problem
  > but I doubt the index will be different. I need to have a precise
  > dispersion curve (index vs. wavelength) for optical devices. The index
  > mentioned in publised papers varies greatly and is available only for a
  > few individual wavelengths. This index variation could be caused by
  > different processing conditions. Therefore, the index should ideally be
  > measured for my own process. But I would appreciate if someone can give me
  > a dispersion curve for SU-8 in VIS-NIR range.
  >
  > Best regards,
  >
  > Xianling Chen
  >
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  > Visit us at http://www.memsnet.org/
  >


  --
  "Its better to lose your pride for someone you love,
   than to lose that someone you love for your useless pride"

  "Whether it happens in a hundred years or a thousand years or a
  million years, eventually our sun will grow cold and go out. When that
  happens, it won't just take us. It'll take Marilyn Monroe and Lao-Tzu
  and Einstein and Morobuto and Buddy Holly and Aristophanes... and all
  of this... all of this was for nothing, unless we go to the stars. -
  Commander Sinclair, "Infection" "

  Kamal Yadav
  Graduate Student
  Rose Hulman Institute of Technology
  Terre Haute
  Indiana 47803


  ------------------------------

  Message: 2
  Date: Sun, 15 Aug 2004 23:33:08 -0700 (PDT)
  From: Siripon Sukuabol 
  Subject: [mems-talk] Piezoelectric Beam Simulation by using Ansys
  To: [email protected]
  Message-ID: <[email protected]>
  Content-Type: text/plain; charset=us-ascii

  Hi..All;


  Please give me your advices.

  Does anyone know where I can find/get the
  examples/tutorials of piezoelectric beam simulation by
  using Ansys software?


  Thanks for your kindness.


  Siripon










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  ------------------------------

  Message: 3
  Date: Mon, 16 Aug 2004 11:25:53 +0200
  From: "Erik Jung" 
  Subject: [mems-talk] Removal of reflowed AZ resist
  To: "General MEMS discussion" 
  Message-ID: 
  Content-Type: text/plain; charset="us-ascii"

  Dear all,
  anyone of you has experience in completely removing AZ photoresist after
  reflowing SnAg solder in the openings (Tmax~230?C, t@Tmax ~ 40sec)
  Thank you!

  Erik
  TU Berlin



  ------------------------------

  Message: 4
  Date: Mon, 16 Aug 2004 15:22:11 +0100
  From: "Matthew Davies" 
  Subject: [mems-talk] Double depth SU-8
  To: 
  Message-ID: <001d01c4839c$6bec94a0$ec8cc593@bagger>
  Content-Type: text/plain; charset="Windows-1252"

  Hi all

  I'm trying to find out if there is an easy method for seeing developed
  SU-8 through another layer of SU-8.  We are trying to make devices
  requiring double depth processing and the aligning of the photomask for
  the second layer is very difficult as we are currently unable to see the
  developed SU-8 on the bottom layer.  At the moment we need to
  overdevelop the bottom SU-8 layer until cracks appear at which point we
  can see the cracks through the top layer of SU-8.

  Any suggestions would be much appreciated.

  Thanks all

  Matt Davies
  STRC, University of Hertfordshire

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