1、Designation: F 1372 93 (Reapproved 2005)Standard Test Method forScanning Electron Microscope (SEM) Analysis of MetallicSurface Condition for Gas Distribution SystemComponents1This standard is issued under the fixed designation F 1372; the number immediately following the designation indicates the ye
2、ar oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONSemiconductor clean rooms are serviced by high-purity
3、 gas distribution systems. This test methodpresents a procedure that may be applied for the evaluation of one or more components considered foruse in such systems.1. Scope1.1 This test method covers the testing of interior surfacesof components such as tubing, fittings, and valves for surfacemorphol
4、ogy.1.2 This test method applies to all surfaces of tubing,connectors, regulators, valves, and any metal component,regardless of size.1.3 Limitations:1.3.1 This methodology assumes a SEM operator skill leveltypically achieved over a 12-month period.1.3.2 This test method shall be limited to the asse
5、ssment ofpits, stringer, tears, grooves, scratches, inclusions, steppedgrain boundaries, and other surface anomalies. However, stainsand particles that may be produced during specimen prepara-tion should be excluded in the assessment of anomalies.1.4 The values stated in SI units are to be regarded
6、as thestandard. The inch-pound units given in parentheses are forinformation only.1.5 This standard 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 d
7、etermine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 6.2. Referenced Documents2.1 NIST Standards:SRM 484 F SEM Magnification Standard2SRM 20690 SEM Performance Standard23. Terminology3.1 Definitions:3.1.1 defecta pit, scratch, groove, inc
8、lusion, stringer,stepped grain boundary, crack, or other surface feature that iseither characteristic of the material or a result of its processingthat is not a result of the sample preparation.3.1.2 grid sizethe grid size (length of the x- and y-axisgrid dimension) will be 1.814 m multiplied by the
9、 magnifi-cation of the photomicrograph. For example, for a standard 4by 5-in. photographic image at 3500 3 magnification, the gridwould be 0.635 by 0.635 cm (0.25 by 0.25 in.).3.1.3 groovea two-dimensional defect on the surface thathas depth and width.3.1.3.1 DiscussionFor this kind of defect, the d
10、epth isgreater than the width, or, conversely, the width is greater thanthe depth.3.1.4 inclusion particles of a foreign material in a metallicmatrix (see Fig. 1).3.1.4.1 DiscussionThese particles are usually compounds(such as oxides, nitrides, carbo-nitrides, sulfides, or silicates),but may be of a
11、ny substance (and is essentially insoluble in themetal matrix).3.1.5 number of anomaliesthe total number of defects perphotomicrograph (see 10.1.1).3.1.6 particles that loosely adhereparticles in which over34 of the bulk of the particle is above the plane of the surface.3.1.6.1 DiscussionThese parti
12、cles generally appear verybright, and little detail of the surface of the particle is seenwhen the contrast and brightness are adjusted to image thesample surface.3.1.7 pita small, sharp, roughly circular cavity in themetal surface (see Fig. 2).1This test method is under the jurisdiction of ASTM Com
13、mittee F01 onElectronics and is the direct responsibility of Subcommittee F01.10 on ProcessingEnvironments.Current edition published Jan. 1, 2005. Approved January 2005. Originallyapproved in 1992. Last previous edition approved in 1999 as F 1372 93(1999).2Available from National Institute of Standa
14、rds and Technology, Gaithersburg,MD 20899.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.8 sample anglethat angle measured normal to theincoming electron beam.3.1.9 scratch a one-dimensional defect on the surfacesuch as a line o
15、n the surface.3.1.9.1 DiscussionFor this type of defect, the depth of thedefect is no deeper than the width of the defect.3.1.10 standard conditions101.3 kPa, 0.0C (14.73 psia,32.0F).3.1.11 stepped grain boundarya grain boundary that hasbeen etched to form a sudden change in height betweenadjacent g
16、rains.3.1.12 stringerin wrought materials, an elongated con-figuration of microconstituents or inclusions aligned in thedirection of working (see Fig. 3).3.1.12.1 DiscussionIn electropolished stainless steel(SST), the stringer defect may have inclusion material on it, orthe material may have been re
17、moved during electropolishing orcleaning, leaving an elongated void.3.1.13 working distancethe distance between the bottomof the objective lens and the sample.4. Significance and Use4.1 The purpose of this test method is to define a procedurefor testing components being considered for installation i
18、nto ahigh-purity gas distribution system. Application of this testmethod is expected to yield comparable data among compo-nents tested for purposes of qualification for this installation.5. Apparatus5.1 Materials:5.1.1 Mounting Stubs, specific to the instrument used arerequired.5.1.2 Adhesives, must
19、 be vacuum stable, to attach samplesto sample stubs. Any adhesive that provides a conductive pathis acceptable.5.1.3 Photomicrosamples, must include the following infor-mation through the use of electronic notation on the SEMscreen or ink on the back of the photomicrograph: sampleidentification, mag
20、nification, and date.5.1.4 Scale Marker, (calibration bar) must be present andclearly visible on all photographs.5.2 Instrumentation:5.2.1 Scanning Electron Microscope (SEM) The SEMused for this study should have a minimum point-to-pointresolution of 30 nm as measured with NIST Standard SRM20696 or
21、equivalent. A high resolution commercially availableSEM with photographic capabilities is recommended. The hardcopy photomicrographic medium from which the defect countis taken must have an area of 100 cm2.5.2.2 Instrument Operating Parameters, shall be as follows:accelerating voltage, 20 KeV; worki
22、ng distance, 10 to 30 mm;sample tilt, 0; and, final aperture size, 150 m or less.5.2.3 Magnification for quantitative pass/fail analysis shallbe five randomly chosen areas photographed at 3500 6 1003.5.2.4 Instruments will be calibrated every 6 months andcalibration verified prior to starting a seri
23、es of test methodFIG. 1 Example of Inclusion (3600 3 magnification)FIG. 2 Example of Pit Defect (3600 3 magnification)FIG. 3 Example of Stringer (3600 3 magnification)F 1372 93 (2005)2measurements using standard laboratory practices and manu-facturers recommendations. Archive or supply magnification
24、calibration check with results.5.2.5 Setup and Schematic, to be furnished by instrumentmanufacturer.6. Hazards6.1 Observe all normal and acceptable precautions regard-ing use of high voltage, X-ray producing equipment.7. Sampling, Test Specimens, and Test Units7.1 Prepare the samples according to 9.
25、1 of this test methodto expose the surface.7.2 Sample preparation shall not cause the temperature ofthe sample to exceed 90C (194F).7.3 Mount the samples onto SEM compatible mounts in amanner that avoids contamination of the surface to be ana-lyzed.7.4 Use adhesives, when necessary, in a manner that
26、 doesnot contaminate the area of interest.7.5 Do not coat samples with a conductive thin layer (forexample, gold or carbon).8. Calibration8.1 Calibrate instruments regularly using standard labora-tory practices and manufacturers recommendations.9. Procedure9.1 Sample Cutting and Mounting:9.1.1 Use a
27、ny mechanical cutting method that minimizesalteration of the surface. A clean, dry hacksaw is preferred.9.1.2 After cutting, clean samples in a reagent grade solventand rinse with a reagent grade isopropyl alcohol (IPA). Placesamples in a nitrogen-filled, resealable, non-outgassing con-tainer.9.1.3
28、Mount samples on the instrument stub.9.2 Introduce the sample stub into the SEM vacuum cham-ber.9.3 Activate the electron beam when vacuum conditionsmeet those recommended by the manufacturer.9.4 Move the sample until an area of interest on thesamples surface comes into focus. Make sure that the are
29、a ofinterest is representative of the whole, avoiding gross defor-mities.9.5 Orient the sample to the degree that the longitudinal axisof the sample curvature, if applicable, is aligned with the axisof the secondary detector.9.6 Increase the magnification to 20 000 to 40 0003 forfinal focus, correct
30、ing astigmatism, and other instrumentanomalies to yield a clear image.9.7 Decrease the magnification to 3500 6 1003 and recordthe image on a photographic medium.9.8 Move to a second random area and repeat the proce-dures in 9.5 through 9.7 for four additional sample sites. Ifadditional analyses are
31、required, they may be performed at thistime, for example, energy dispersive X-ray spectrometer(EDX).9.9 Turn off the SEM electron beam and remove the samplefrom the vacuum chamber.10. Interpretation of Results10.1 Data Presentation:10.1.1 Overlay the recorded images with a scale as definedin 3.1.4.
32、The grid line should be as fine as possible and stillremain clearly visible. The lower left corner of the grid is tocorrespond with the lower left corner of the photograph. Sumthe number of surface anomalies per square (such as pits,scratches, inclusions, and stringers) as the total per micrograph.D
33、efects that appear in one or more adjacent squares shall countas one defect for each square occupied by the defect. Particlesthat loosely adhere to the surface must be presumed to beartifacts from atmosphere or sample preparation techniques,etc, and therefore will be ignored.10.1.2 Present the data
34、as photomicrographs (five from eachsample) and in tabular form, showing total number of particlescounted (per area analyzed) in the grid overlay. Photomicro-graphs must include the following information through the useof electronic notation on the SEM screen or ink on the back ofthe photomicrograph:
35、 sample identification, magnification, anddate. The data table shall include a summation of the totalcounts for all five micrographs with the average and themaximum count for any one micrograph.10.1.3 Use illustrations wherever confusion may exist re-garding the area of analysis or whenever multiple
36、 sites on onesample must be identified.10.1.4 The EDX spectra and corresponding photographsshould be appropriately labeled so that the elemental compo-sition of any specific defect, particle, or anomaly is readilyapparent to any third party.11. Report11.1 Report the following information:11.1.1 EDX
37、spectra and related photomicrographs mustinclude the following information: sample identification, date,peak identification, tilt angle, and voltage,11.1.2 All data reported must identify the SEM equipmentmanufacturer and model number, and11.1.3 Any special modifications in equipment or procedurenec
38、essary to acquire data must also be documented and fullydescribed.12. Precision and Bias12.1 Precision and bias for this test method are beingdetermined.13. Keywords13.1 components; contamination; gas distribution; metallicsurface condition; SEM analysis; semiconductor processing;surface conditionF
39、1372 93 (2005)3ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of s
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42、he 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).F 1372 93 (2005)4
