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-----Original Message-----
From: Comtois John H MAJ AFRL/VSSE
Sent: Thursday, June 17, 1999 9:28 AM
To: ' at smtpgw1'; '[email protected] at
smtpgw1'
Subject: RE: L-edit as a MEMS design tool


Yahong,

I've used a lot of CAD tools for MEMS (Magic, Cadence, L-Edit, AutoCAD), and
L-Edit is good'n'cheap, though you have to overlook certain 'features', like
'saving as' a .DAT file instead of a .TDB file.  Also, you can't flatten a
single cell - you have to go into the cell, copy it, back out and paste the
polygons - if you say 'flatten, it flattens ALL the cells.  That's not
necessarily bad, just different from other tools.  Also, each different tool
will call an object or activity by a different name, you just have to
decipher each now tool's nomenclature.

CAD tools generally don't come with MEMS library parts, you usually get
those from the fabrication vendor because they are specific to that process.
I know that MCNC (now spun off as Cronos) was putting together a library of
parts for the MUMPS process, and Sandia has a library of parts for the
SUMMiT process (for AutoCAD).

However, as Ying Xu says, library parts are mostly good for learning
purposes, or you can flatten them and re-use the polygons.  By and large
most MEMS devices are drawn from scratch or built from a library of cells
that you have put together yourself.  Apart from hinges and simple
actuators, there's really no way a MEMS library could hold exactly the parts
you need with the exact dimensions and features you need.  The parts in
there mostly serve as examples.  MEMS is generally not like CMOS where
'parts is parts' and you can wire them together like one of those 100-in-1
electronic kits, and whole designs can be generated automatically by
software like Synopsis.

Having just spent nearly 2 days straight with L-Edit, so I would say start
drawing your own personnal library of cells now.  Start by copying designs
from the pictures in journals.  I just saw a neat fold-up pyramidal-shaped
microphone (from Lucent I think) in a commercial magazine.  Re-drawing
things like that are good practice.

Good Luck and have fun.

John



-----Original Message-----
From:  at smtpgw1
Sent: Tuesday, May 25, 1999 8:27 AM
To: [email protected] at smtpgw1
Subject: RE: L-edit as a MEMS design tool


Hi, mems designers,

It is true that the library elements in MEMS Pro don't have much practical
value for MEMS designers, but it is good for educational purpose.

Besides this, MEMS Pro provides a lot features to enhance the practical
designs,

1. Besides the well known features of L-edit for IC design, MEMS Pro L-edit
has improved drawing functions of arbitrary curved features, which is very
helpful to mems 'arbitrary' geometry drawing requirement.
2. MEMS Pro 3D Tool can generate 3D structure automatically from 2D layout
based on your customized process steps. It has and cross section view on 3D
structure at any 'cut' you want.
3. Besides the commercial foundry technology setups (ADIMEMS, Sandia ITT,
MCNC MUMPs, MOSIS), it is very easy to set up your own layers and
fabrication process and design rules.
4. For modeling purpose:
(1) you can do FEA by interfacing with ANSYS (export the 3D structure to ANF
format-ANSYS Native Format). You can further extract model parameters to
build macro models for your device for system level simulation at much
faster speed.
(2) You can write C, C++ program to do the modeling of your device then use
MEMS Pro T-Spice engine to do simulation
(3) You can generate a table from experiments, and T-Spice can take in the
data to do simulation.

Just listed some. You are welcome to do evaluation of the tool by contacting
(626)-792-3000 or visit our website http://www.tanner.com/eda

Ying Xu
MEMS Applications Engineer
Tanner Research Inc.
2650 E. Foothill Blvd.
Pasadena, CA 91107
phone: (626)-792-3000
fax: (626)-432-5705

-----Original Message-----
From: Yahong Yao [mailto:[email protected]]
Sent: Saturday, May 22, 1999 9:50 PM
To: [email protected]
Subject: L-edit as a MEMS design tool


Hello everyone,

I am going to use L-edit to design mask layout for MEMS. It seems very
convenient to be used in IC layout because there are many standard devices
regarding to microelectronics for instance, CMOS, FET, NPN and so on.
What's the advantage to use it in MEMS? I think we can't use the standard
cells because they are meaningless to MEMS, is that right?

Any comments are greatly appreciated!

Yahong
------------------------
Yahong Yao
705K University Village
Columbia, MO 65203
Tel: (573)771-0382
Email:[email protected]


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