1、Designation: E 2444 05e1Terminology Relating toMeasurements Taken on Thin, Reflecting Films1This standard is issued under the fixed designation E 2444; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEEditorial changes were made throughout in January 2006.1. Scope1.1 This standard consists of terms and definitions pertain-ing to measurements
3、 taken on thin, reflecting films, such asfound in microelectromechanical systems (MEMS) materials.In particular, the terms are related to the standards in Section 2,which were generated by Committee E08 on Fatigue andFracture. Terminology E 1823 Relating to Fatigue and FractureTesting is applicable
4、to this standard.1.2 The terms are listed in alphabetical order.2. Referenced Documents2.1 ASTM Standards:2E 1823 Terminology Relating to Fatigue and Fracture Test-ingE 2244 Test Method for In-Plane Length Measurements ofThin, Reflecting Films Using an Optical InterferometerE 2245 Test Method for Re
5、sidual Strain Measurements ofThin, Reflecting Films Using an Optical InterferometerE 2246 Test Method for Strain Gradient Measurements ofThin, Reflecting Films Using an Optical Interferometer3. Terminology3.1 Terms and Their Definitions:2-D data tracea two-dimensional group of points that isextracte
6、d from a topographical 3-D data set and that isparallel to the xz-oryz-plane of the interferometer. E 22443-D data seta three-dimensional group of points with atopographical z-value for each (x, y) pixel location within theinterferometers field of view. E 2244anchorin a surface-micromachining proces
7、s, the portion ofthe test structure where a structural layer is intentionallyattached to its underlying layer. E 2244anchor lipin a surface-micromachining process, the free-standing extension of the structural layer of interest aroundthe edges of the anchor to its underlying layer.DISCUSSIONIn some
8、processes, the width of the anchor lip may bezero. E 2244bulk micromachininga MEMS fabrication process wherethe substrate is removed at specified locations. E 2244cantilevera test structure that consists of a freestandingbeam that is fixed at one end. E 2246fixed-fixed beam a test structure that con
9、sists of a freestand-ing beam that is fixed at both ends. E 2245in-plane length (or deflection) measurement, L (or D)Lthe experimental determination of the straight-linedistance between two transitional edges in a MEMS device.DISCUSSIONThis length (or deflection) measurement is made paral-lel to the
10、 underlying layer (or the xy-plane of the interferometer).E 2244interferometera non-contact optical instrument used toobtain topographical 3-D data sets.DISCUSSIONThe height of the sample is measured along the z-axisof the interferometer. The interferometers x-axis is typically alignedparallel or pe
11、rpendicular to the transitional edges to be measured.E 2244MEMSmicroelectromechanical systems. E 2244microelectromechanical systems, MEMSin general, thisterm is used to describe micron-scale structures, sensors, andactuators and the technologies used for their manufacture(such as, silicon process te
12、chnologies), or both. E 2244out-of-plane measurements Lexperimental data taken onstructures that are curved in the interferometers z-direction(that is, perpendicular to the underlying layer). E 2444residual strain, erin a MEMS process, the amount ofdeformation (or displacement) per unit length const
13、rained1This test method is under the jurisdiction of ASTM Committee E08 on Fatigueand Fracture and is the direct responsibility of Subcommittee E08.05 on CyclicDeformation and Fatigue Crack Formation.Current edition approved May 1, 2005. Published May 2005.2For referenced ASTM standards, visit the A
14、STM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Uni
15、ted States.within the structural layer of interest after fabrication yetbefore the constraint of the sacrificial layer (or substrate) isremoved (in whole or in part) E 2245sacrificial layera single thickness of material that is inten-tionally deposited (or added) then removed (in whole or inpart) du
16、ring the micromachining process, to allow freestand-ing microstructures. E 2244stictionadhesion between the portion of a structural layerthat is intended to be freestanding and its underlying layer.E 2246(residual) strain gradient, sgL1a through-thicknessvariation (of the residual strain) in the str
17、uctural layer ofinterest before it is released.DISCUSSIONIf the variation through the thickness in the structurallayer is assumed to be linear, it is calculated to be the positivedifference in the residual strain between the top and bottom of acantilever divided by its thickness. Directional informa
18、tion is assignedto the value of s. E 2246structural layera single thickness of material present in thefinal MEMS device. E 2444substratethe thick, starting material (often single crystalsilicon or glass) in a fabrication process that can be used tobuild MEMS devices. E 2244support regionin a bulk-mi
19、cromachining process, the areathat marks the end of the suspended structure. E 2244surface micromachininga MEMS fabrication processwhere micron-scale components are formed on a substrateby the deposition (or addition) and removal (in whole or inpart) of structural and sacrificial layers. E 2244test
20、structurea component (such as, a fixed-fixed beam orcantilever) that is used to extract information (such as, theresidual strain or the strain gradient of a layer) about afabrication process. E 2244transitional edgethe side of a MEMS structure that ischaracterized by a distinctive out-of-plane verti
21、cal displace-ment as seen in an interferometric 2-D data trace. E 2244underlying layer the single thickness of material directlybeneath the material of interest.DISCUSSIONThis layer could be the substrate. E 22444. Keywords4.1 cantilevers; definitions; fixed-fixed beams; interferom-etry; length meas
22、urements; microelectromechanical systems;MEMS; polysilicon; residual strain; stiction; strain gradient;terminology; test structureASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard a
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25、ou may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).E244405e12
