ASTM E2246-11e1

Standard Test Method for Strain Gradient Measurements of Thin, Reflecting Films Using an Optical Interferometer

SIGNIFICANCE AND USE
5.1 Strain gradient values are an aid in the design and fabrication of MEMS devices.
SCOPE
1.1 This test method covers a procedure for measuring the strain gradient in thin, reflecting films. It applies only to films, such as found in microelectromechanical systems (MEMS) materials, which can be imaged using an optical interferometer, also called an interferometric microscope. Measurements from cantilevers that are touching the underlying layer are not accepted.  
1.2 This test method uses a non-contact optical interferometric microscope with the capability of obtaining topographical 3-D data sets. It is performed in the laboratory.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Oct-2011
• ICS: 37.040.20 - Photographic paper, films and plates. Cartridges
• Technical Committee: E08 - Fatigue and Fracture
• Drafting Committee: E08.05 - Cyclic Deformation and Fatigue Crack Formation

Relations

• Replaces: ASTM E2246-11 - Standard Test Method for Strain Gradient Measurements of Thin, Reflecting Films Using an Optical Interferometer
• Effective Date: 01-Nov-2011
• Replaced By: ASTM E2246-11(2018) - Standard Test Method for Strain Gradient Measurements of Thin, Reflecting Films Using an Optical Interferometer (Withdrawn 2023)
• Effective Date: 01-May-2018
• Referred By: ASTM E2244-11(2018) - Standard Test Method for In-Plane Length Measurements of Thin, Reflecting Films Using an Optical Interferometer (Withdrawn 2023)
• Effective Date: 01-Nov-2011
• Referred By: ASTM E2245-11(2018) - Standard Test Method for Residual Strain Measurements of Thin, Reflecting Films Using an Optical Interferometer (Withdrawn 2023)
• Effective Date: 01-Nov-2011
• Referred By: ASTM E2444-11(2018) - Standard Terminology Relating to Measurements Taken on Thin, Reflecting Films
• Effective Date: 01-Nov-2011

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
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Designation:E2246 −11
Standard Test Method for
Strain Gradient Measurements of Thin, Reflecting Films
1
Using an Optical Interferometer
This standard is issued under the fixed designation E2246; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
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ε NOTE—Reference (1) was editorially revised in September 2013.
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1. Scope 2.2 SEMI Standard:
MS2Test Method for Step Height Measurements of Thin
1.1 This test method covers a procedure for measuring the
Films
strain gradient in thin, reflecting films. It applies only to films,
such as found in microelectromechanical systems (MEMS)
3. Terminology
materials,whichcanbeimagedusinganopticalinterferometer,
also called an interferometric microscope. Measurements from 3.1 Definitions:
cantilevers that are touching the underlying layer are not 3.1.1 The following terms can be found in Terminology
accepted. E2444.
3.1.2 2-D data trace, n—a two-dimensional group of points
1.2 This test method uses a non-contact optical interfero-
that is extracted from a topographical 3-D data set and that is
metricmicroscopewiththecapabilityofobtainingtopographi-
parallel to the xz-or yz-plane of the interferometric micro-
cal 3-D data sets. It is performed in the laboratory.
scope.
1.3 This standard does not purport to address all of the
3.1.3 3-D data set, n—a three-dimensional group of points
safety concerns, if any, associated with its use. It is the
with a topographical z-value for each (x, y) pixel location
responsibility of the user of this standard to establish appro-
within the interferometric microscope’s field of view.
priate safety and health practices and determine the applica-
3.1.4 anchor, n—in a surface-micromachining process, the
bility of regulatory limitations prior to use.
portion of the test structure where a structural layer is inten-
2. Referenced Documents tionally attached to its underlying layer.
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3.1.5 anchor lip, n—in a surface-micromachining process,
2.1 ASTM Standards:
the freestanding extension of the structural layer of interest
E2244Test Method for In-Plane Length Measurements of
around the edges of the anchor to its underlying layer.
Thin, Reflecting Films Using an Optical Interferometer
3.1.5.1 Discussion—In some processes, the width of the
E2245Test Method for Residual Strain Measurements of
anchor lip may be zero.
Thin, Reflecting Films Using an Optical Interferometer
E2444Terminology Relating to Measurements Taken on
3.1.6 bulk micromachining, adj—a MEMS fabrication pro-
Thin, Reflecting Films
cess where the substrate is removed at specified locations.
E2530Practice for Calibrating the Z-Magnification of an
3.1.7 cantilever, n—a test structure that consists of a free-
Atomic Force Microscope at Subnanometer Displacement
standing beam that is fixed at one end.
Levels Using Si(111) Monatomic Steps (Withdrawn
3
3.1.8 fixed-fixed beam, n—a test structure that consists of a
2015)
freestanding beam that is fixed at both ends.
3.1.9 in-plane length (or deflection) measurement, n—the
1 experimental determination of the straight-line distance be-
This test method is under the jurisdiction ofASTM Committee E08 on Fatigue
and Fracture and is the direct responsibility of Subcommittee E08.05 on Cyclic
tween two transitional edges in a MEMS device.
Deformation and Fatigue Crack Formation.
3.1.9.1 Discussion—This length (or deflection) measure-
Current edition approved Nov. 1, 2011. Published January 2012. Originally
ment is made parallel to the underlying layer (or the xy-plane
approved in 2002. Last previous edition approved in 2005 as E2246–05.
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of the interferometric microscope).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
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The last approved version of this historical standard is referenced on For referenced Semiconductor Equipment and Materials International (SEMI)
www.astm.org. standards, visit the SEMI website, www.semi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E2246−11
3.1.10 interferometer, n—a non-contact optical instrument and σ ) where σ is the standard deviation of the six
same2 same1
used to obtain topographical 3-D data sets. step height measurements taken on the physical step height
3.1.10.1 Discussion—The height of the sample is measured standardatthesamelocationbeforethedatasessionandσ
same2
along the z-axis of the inte
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