1、Designation: E2444 11Terminology Relating toMeasurements Taken on Thin, Reflecting Films1This standard is issued under the fixed designation E2444; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、 in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This standard consists of terms and definitions pertain-ing to measurements taken on thin, reflecting films, such asfound in microelectromech
3、anical 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 E1823 Relating to Fatigue and FractureTesting is applicable to this standard.1.2 The terms are listed in alphabetical order.2.
4、Referenced Documents2.1 ASTM Standards:2E1823 Terminology Relating to Fatigue and Fracture Test-ingE2244 Test Method for In-Plane Length Measurements ofThin, Reflecting Films Using an Optical InterferometerE2245 Test Method for Residual Strain Measurements ofThin, Reflecting Films Using an Optical I
5、nterferometerE2246 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 isextracted from a topographical 3-D data set and that isparallel to the xz-oryz-
6、plane of the interferometric micro-scope. E22443-D data seta three-dimensional group of points with atopographical z-value for each (x, y) pixel location within theinterferometric microscopes field of view. E2244anchorin a surface-micromachining process, the portion ofthe test structure where a stru
7、ctural layer is intentionallyattached to its underlying layer. E2244anchor 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 processes, the width of the anchor lip may bezero
8、. E2244bulk micromachininga MEMS fabrication process wherethe substrate is removed at specified locations. E2244cantilevera test structure that consists of a freestandingbeam that is fixed at one end. E2246fixed-fixed beam a test structure that consists of a freestand-ing beam that is fixed at both
9、ends. E2245in-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 underlying layer (or the xy-plane of the interferome
10、tricmicroscope). E2244interferometera 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 x-axis is typically aligned parallel orperpendicular to the transitional edges to be measured. E224
11、4MEMSmicroelectromechanical systems. E2244microelectromechanical systems, MEMSin general, thisterm is used to describe micron-scale structures, sensors,actuators, and technologies used for their manufacture (suchas, silicon process technologies), or combinations thereof.E2244residual strain, rin a M
12、EMS process, the amount ofdeformation (or displacement) per unit length constrainedwithin the structural layer of interest after fabrication yetbefore the constraint of the sacrificial layer (or substrate) isremoved (in whole or in part) E2245sacrificial layera single thickness of material that is i
13、nten-tionally deposited (or added) then removed (in whole or inpart) during the micromachining process, to allow freestand-ing microstructures. E2244stictionadhesion between the portion of a structural layerthat is intended to be freestanding and its underlying layer.E22461This test method is under
14、the jurisdiction of ASTM Committee E08 on Fatigueand Fracture and is the direct responsibility of Subcommittee E08.02 on Standardsand Terminology.Current edition approved Oct. 15, 2011. Published December 2011. Orginiallyapproved in 2005. Last previous edition approved in 2005 as E2444051. DOI:10.15
15、20/E2444-11.2For referenced ASTM standards, visit the ASTM 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 Dr
16、ive, PO Box C700, West Conshohocken, PA 19428-2959, United States.(residual) strain gradient, sgL1a through-thicknessvariation (of the residual strain) in the structural layer ofinterest before it is released.DISCUSSIONIf the variation through the thickness in the structurallayer is assumed to be li
17、near, it is calculated to be the positivedifference in the residual strain between the top and bottom of acantilever divided by its thickness. Directional information is assignedto the value of s. E2246structural layera single thickness of material present in thefinal MEMS device. E2244substratethe
18、thick, starting material (often single crystalsilicon or glass) in a fabrication process that can be used tobuild MEMS devices. E2244support regionin a bulk-micromachining process, the areathat marks the end of the suspended structure. E2244surface micromachininga MEMS fabrication processwhere micro
19、n-scale components are formed on a substrateby the deposition (or addition) and removal (in whole or inpart) of structural and sacrificial layers. E2244test structurea component (such as, a fixed-fixed beam orcantilever) that is used to extract information (such as, theresidual strain or the strain
20、gradient of a layer) about afabrication process. E2244transitional edgethe side of a MEMS structure that ischaracterized by a distinctive out-of-plane vertical displace-ment as seen in an interferometric 2-D data trace. E2244underlying layer the single thickness of material directlybeneath the mater
21、ial of interest.DISCUSSIONThis layer could be the substrate. E22444. Keywords4.1 cantilevers; definitions; fixed-fixed beams; interferom-etry; length measurements; microelectromechanical systems;MEMS; polysilicon; residual strain; stiction; strain gradient;terminology; test structureASTM Internation
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