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MEMS Calculator
developed
at the National Institute of Standards and Technology for
use with ASTM and SEMI standards |
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This MEMS
Calculator
determines the following thin film properties from data taken with
an optical interferometer: a) residual strain from fixed-fixed beams,
b) strain gradient from
cantilevers, c) step heights or thicknesses from step-height
test structures, and d) in-plane lengths or deflections. An optical vibrometer is used to obtain
Young's modulus from resonating cantilevers, and a material test
machine is used to obtain the wafer bond strength from micro-chevron
test structures. |
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Two symbols can be used to help navigate through this
web page:
 -
This symbol denotes items applicable to the 2008 MEMS Young's Modulus
and Step Height Round Robin Experiment; however, the pertinent data
sheets should be considered generic.
 - This symbol denotes items applicable to the MNT 5-in-1
Standard Reference Material (SRM);
however, the pertinent data sheets should be considered generic.
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For the MEMS Calculator, the following material is
available:
1) User
Guides:
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a) |
UsersGuide.YM.pdf |
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This User's
Guide provides helpful information pertaining to the 2008
MEMS Young's
Modulus and Step Height Round Robin Experiment. |
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b) |
UsersGuide.SRM.pdf |
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This User's
Guide (currently being developed) provides helpful information pertaining to the MNT
5-in-1 SRM. Click here
for additional information. |
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c) |
UsersGuide.L&S.pdf |
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This User's
Guide was used during the 2002 ASTM MEMS Length and Strain Round Robin
Experiment and provides helpful information pertaining to residual
strain, strain gradient, and in-plane length measurements. |
2)
Parameters under consideration and the data sheets used for on-line
calculations:
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a) |
Young's
modulus (using SEMI standard MS4) |
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i) |
Data Sheet YM.1- Using single layered resonating
cantilevers |
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ii) |
Data Sheet YM.2 - For all the layers in a CMOS process
(under development) |
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b) |
Residual
strain (using ASTM standard E 2245) |
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i) |
Data Sheet
RS.1- Using fixed-fixed beam test structures |
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ii) |
Data Sheet
RS.2 - Using fixed-fixed beam test structures
and a more detailed calculation of the combined standard
uncertainty, uc
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c) |
Strain
gradient (using ASTM standard E 2246) |
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i) |
Data Sheet
SG.1- Using cantilever test structures |
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ii) |
Data Sheet
SG.2 - Using cantilever test structures and a
more detailed calculation of uc
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d) |
Step height or
Thickness (using SEMI standard MS2) |
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i) |
Data Sheet
SH.1- Step heights from one 3-D data
set |
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ii) |
Data Sheet
SH.2 - Step heights from two 3-D data
sets taken during the same data session |
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iii) |
Data Sheet
SH.3 - Step heights from two 3-D data
sets taken during different data sessions |
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iv) |
Data Sheet
SH.4 - Thicknesses of all the layers in a CMOS
process using electro-physical technique |
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e) |
In-plane
length or Deflection (using ASTM standard E 2244) |
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i) |
Data Sheet
L.1- In-plane lengths with two ends anchored |
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ii) |
Data Sheet
L.2 -
In-plane lengths with transitional edges
oriented in the same direction |
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iii) |
Data Sheet
L.3 -
In-plane lengths with one end anchored |
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iv) |
Data Sheet
L.4 -
In-plane lengths with two ends
unanchored |
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v) |
Data Sheet
L.5 -
In-plane deflections from released part
to released part |
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vi) |
Data Sheet
L.6 -
In-plane deflections from released part
to fixed location |
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f) |
Wafer bond
strength (using SEMI standard MS5) |
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i) |
Data Sheet
WBS.1 - Using micro-chevron test structures |
3) Design files and accompanying tiff files:
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The following two design files (in
GDS-II format), as shown in the
accompanying tiff files, were used to fabricate
the 2008 MEMS Young's Modulus and Step Height
Round Robin Experiment Test Chips.
These files also double as the design
files for the prototype MNT 5-in-1 SRMs: |
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a) |
5n1MUMPs80.gds
5n1MUMPs80.tif |
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This design file
(in GDS-II format) and corresponding tiff file are for the chip fabricated on the MUMPs80.
Visit
MEMSCAP
(http://www.memscap.com) for fabrication specifics. |
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b) |
5n1CMOS.gds
5n1CMOS.tif |
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This design file
(in GDS-II format) and corresponding tiff file are for the
chip fabricated on a
1.5 mm CMOS process
available through MOSIS.
Visit
MOSIS
(http://www.mosis.com) for fabrication specifics. |
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The following two design files (in
GDS-II format), as shown in the
accompanying tiff files, were used to fabricate
the 2002 ASTM MEMS Length and Strain Round Robin
Experiment Test Chips and may
also be used for instructional purposes
in conjunction with Data Sheets RS, SG,
and L: |
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c) |
mumps46.gds
mumps46.tif |
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This design file
(in GDS-II format) and corresponding tiff file are for the chip fabricated on the MUMPs46.
Visit
MEMSCAP
(http://www.memscap.com) for fabrication specifics. |
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d) |
music1.gds
music1.tif |
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This design file
(in GDS-II format) and corresponding tiff file are for the chip fabricated on the second
surface-micromachining MUSiC processing run. |
4)
List of pertinent SEMI standard test methods:
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Consult the following three SEMI
standards for details concerning
the inputs
to Data Sheets SH, YM, and WBS: |
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a)
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SEMI
MS2, Test Method for
Step-Height Measurements
of Thin, Reflecting
Films Using an Optical
Interferometer.
Click here
for ordering
information.
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b)
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SEMI
MS4, Test Method for
Young's Modulus
Measurements of Thin,
Reflecting Films Based
on the Frequency of
Beams in Resonance.
Click here
for ordering
information.
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c)
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SEMI
MS5, Test Method for
Wafer Bond Strength
Measurements Using
Micro-Chevron Test
Structures.
Click here
for ordering
information.
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5) List of
pertinent ASTM standard test methods:
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Consult the following three
ASTM standards for details
concerning the inputs to Data Sheets L, RS,
and SG: |
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a) |
ASTM E 2244, Standard
Test Method for In-Plane Length Measurements of Thin,
Reflecting Films Using an Optical Interferometer.Click here
for ordering
information. |
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b) |
ASTM E 2245, Standard
Test Method for Residual Strain Measurements of Thin,
Reflecting Films Using an Optical Interferometer.Click here
for ordering
information. |
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c) |
ASTM E 2246, Standard
Test Method for Strain Gradient Measurements of Thin,
Reflecting Films Using an Optical Interferometer.Click here
for ordering
information. |
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These standards are also available in the
Annual Book of ASTM Standards,
Vol. 03.01.
Click here
for ordering
information. |
6)
List of MEMS terminology standards:
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a) |
ASTM E 2444,
Terminology Relating to Measurements Taken on Thin,
Reflecting Films.
Click here
for ordering
information.
This standard is also available in the
Annual Book of ASTM Standards,
Vol. 03.01.
Click here
for ordering
information. |
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b) |
SEMI MS3,
Terminology for MEMS Technology. Click here
for ordering
information. |
7)
List of other pertinent references:
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a) |
EDL.vol.28.11.07.pdf |
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This Electron Device Letter
presents a method of obtaining the Young's modulus values of
all the layers in a CMOS process. The thicknesses
obtained from the electro-physical technique are amongst the
inputs for the optimization program. |
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b) |
NISTJRes.V112.No5.07.pdf |
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This NIST Journal of Research article
presents the electro-physical technique used to obtain all
the thicknesses in a CMOS process using Data Sheet SH.4.
It also provides the user with a more in-depth understanding
of SEMI standard MS2. |
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c) |
NISTSP1048.pdf |
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This 2006 NIST Special
Publication (NISTSP 1048) lists (on page 309) the US
Measurement System (USMS) critical measurement targets for
accelerating innovation in Micro Nano Technology. |
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d) |
NISTIR7291.pdf |
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This NIST
Internal Report (NISTIR #7291) presents the 2002 ASTM MEMS Length and
Strain Round Robin
Results and the uncertainty equations used in Data Sheets
RS, SG, and L. |
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e) |
NISTIR6779.pdf |
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This NIST
Internal Report (NISTIR #6779) provides the user with a
more in-depth understanding of the ASTM standard test
methods used in Data Sheets RS, SG, and L. |
Email questions or comments to mems-support@nist.gov.
Adobe Acrobat Reader (version 4.0x or
greater) will be needed to view many of these documents. If you do
not have this program, you may
download
it free of charge. The software is identified in order to assist
users of this information service. In no case does such
identification imply recommendation or endorsement by the National
Institute of Standards and Technology.
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