1、Designation: E1634 11Standard Guide forPerforming Sputter Crater Depth Measurements1This standard is issued under the fixed designation E1634; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in p
2、arentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers the preferred procedure for acquiringand post-processing of sputter crater depth measurements. Thisguide is limited to stylus-ty
3、pe surface profilometers equippedwith a stage, stylus, associated scan and sensing electronics,video system for sample and scan alignment, and computerizedsystem.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This stand
4、ard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 AS
5、TM Standards:2E673 Terminology Relating to Surface Analysis3. Terminology3.1 Definitions:3.1.1 Terms used in surface analysis are defined in Termi-nology E673.4. Significance and Use4.1 Sputter crater depth measurements are performed inorder to determine a sputter rate (depth/time) for each matrixsp
6、uttered during a sputter depth profile or similar in-depth typeanalyses. From sputter rate values, a linear depth scale can becalculated and displayed for the sputter depth profile.4.2 Data obtained from surface profilometry are useful inmonitoring instrumental parameters (for example, raster size,s
7、hape, and any irregularities in topography of the sputteredcrater) used for depth profiles.5. General Procedure5.1 Upon completing a sputter depth profile, mark the craterfor future identification (one can mark the exterior corner(s) ofa crater with features, for example, lines, holes, etc., produce
8、dusing an unrastered ion beam). Note the crater orientation withrespect to the other sample features5.2 Place the sample on the profilometer stage surface. If thesample has an area of less than 1 cm2, mount the sample ontoanother larger flat surface to prevent sample movement whenprofilometry is per
9、formed. The system should be reasonablyleveled; for details on instrumental adjustments, see manufac-turers operating manual(s). Keep the environment as dust-freeas possible and dust-off the sample surface with a clean air/gasjet before performing the measurement.5.3 Pre-select surface profilometer
10、operational settings;computerized models are commonly used. Most surface profi-lometers commonly permit selection of the following param-eters:5.3.1 Stylus type (for example, diamond stylus).5.3.2 Stylus radius (for example, 5 m; various stylus radiiare available depending upon desired resolution of
11、 measure-ment, and to a certain degree the strength of the stylus tip forvarying hardness of materials).5.3.3 Stylus force (that is, force exerted on the analyticalsample during operation, for example, 15 mg; this is animportant variable when profiling a sample with high hardnesslevels; damage to th
12、e stylus may occur, and hence damage tothe instrumentation or errors in profilometry measurements, orboth, may result), similarly, excessive force can damage softsamples such as polymers or photoresists and result in errone-ous measurements.5.3.4 Scan speed (for example, 50 m/s; this value isdepende
13、nt upon permissible noise levels, accuracy, etc., and istypically determined experimentally).5.3.5 Scan length (one typically uses twice the crater size toallow for scanning over the level areas about the sputteredcrater.5.3.6 Number of scans for signal averaging (for example,three repetitive scans
14、averaged to improve the signal-to-noiseratio).5.4 Lower the stylus in an area outside the sputtered crater,at a distance from the crater edge of approximately one-half theactual crater size, and in a reasonably smooth area to traverse1This guide is under the jurisdiction of ASTM Committee E42 on Sur
15、faceAnalysis and is the direct responsibility of Subcommittee E42.06 on SIMS.Current edition approved Nov. 1, 2011. Published November 2011. Originallyapproved in 2002. Last previous edition approved in 2007 as E1634 02 (2007).DOI: 10.1520/E1634-11.2For referenced ASTM standards, visit the ASTM webs
16、ite, 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, United Stat
17、es.the entire crater length. The scan path is typically chosen acrossthe center of the sputtered crater in one direction with arepetitive measurement in the perpendicular direction.6. Interpretation of Results6.1 In general, a plot representative of a sputtered crater willresult (see Fig. 1). The da
18、ta may then need post-processing,including leveling, rescaling, zeroing of surface depth, averag-ing top and bottom surface(s), etc. In the leveling process, onenormally chooses a cursor position on the top left and right(outer surface of the crater). Upon leveling, rescaling, andzeroing, the full c
19、rater shape should be visible on the graph,with both top surfaces at the same zero point and the bottomsurface of the crater relatively flat. Some systems permit cursorlocation to define ranges on the top and bottom surfaces of thecrater. The computer would then average and calculate thedifferences
20、to determine an accurate sputter crater depthmeasurement.7. Modified Procedure for Large-Area Craters7.1 For larger diameter ion beam sputter craters, such as arefrequently used for Auger electron spectroscopy and X-rayphotoelectron spectroscopy, it may be too difficult to define theoriginal surface
21、 height and crater depth from the profilometerscan. In these cases, sputter crater depths have been success-fully measured by sputtering the specimen through a metalmesh, such as a 3-mm TEM grid with 500 m openings, thenusing the stylus profilometer to measure the heights of thereplicated mesh patte
22、rn on the sputtered specimen surface.3,4An example is shown in Fig. 2.7.2 It is important for an accurate step-height measure of theoriginal surface and the crater depth that the mesh grid bepositioned directly onto the specimen surface, with no gapseparating the two. Additionally, the mesh material
23、 must beselected so that sputtered contamination from the mesh doesnot interfere with signal from the elements of interest in thespecimen material. This sputtered contamination from themesh will also modestly alter the sputter rate of the specimenmaterial, which may be a concern in some experiments.
24、8. Precision and Accuracy8.1 PrecisionThe precision is determined by repeatingmeasurements several times and reporting the standard devia-tion among values.8.2 AccuracyThe accuracy of the measurement can bedetermined by measuring a calibrated depth standard typicallysupplied with commercial surface
25、profilometers, and calculat-ing a percent difference from the measured value. Bias oftendepends upon stylus limited point size, scan speeds/distances,vibration during measurement(s), condition of apparatus; cali-bration of surface profilometer equipment, etc., and should beconsidered carefully when
26、measuring sputtered crater depthand reporting subsequent data.9. Keywords9.1 Auger electron spectroscopy; secondary ion mass spec-trometry; stylus profilometry; surface analysis; X-ray photo-electron spectroscopy3Suzuki, M., Mogi, K., and Ando, H., “Technical Proposal for Measurement ofSputtered Dep
27、th Using a MeshEspecially for Auger Depth Profiling,” Journalof Surface Analysis, Vol 5, 1999, pp. 188191.4Seah, M.P., Geller, J., and Suzuki, M., “Accurate Measurement of SputteredDepth for Ion Sputtering Rates and Yields: the mesh replica method,” Surface andInterface Analysis, Vol 39, 2007, pp. 6
28、978.FIG. 1 Typical Stylus Profilometer Scan of a Sputtered CraterNOTE 1(a) Scanning electron photomicrograph showing replicationof mesh grid pattern on a specimen after sputtering.(b) Stylus profilometry scan across replicated grid pattern to measuresputter crater depth. Crater depth is marked by do
29、uble-headed arrow.Source: Suzuki, M., Mogi, K., and Ando, H., “Technical Proposal forMeasurement of Sputtered Depth Using a MeshEspecially for AugerDepth Profiling,” Journal of Surface Analysis, Vol 5, 1999, pp. 188191.FIG. 2 Example of Sputter Crater Depth ProfilesE1634 112ASTM International takes
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