ASTM_F_1372_-_93_2012.pdf

Designation:F137293(Reapproved 2012)Standard Test Method forScanning Electron Microscope(SEM)Analysis of MetallicSurface Condition for Gas Distribution SystemComponents1This standard is issued under the fixed designation F1372;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 parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONSemiconductor clean rooms are serviced by high-purity 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 surfacemorphology.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 assessment 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 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 determine 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:3.1.1defecta pit,scratch,groove,inclusion,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.3.1.2grid sizethe grid size(length of the x-and y-axisgrid dimension)will be 1.814 m multiplied by the magnifi-cation of the photomicrograph.For example,for a standard 4by 5-in.photographic image at 3500 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 depth 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 any substance(and is essentially insoluble in themetal matrix).1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.10 on Contamina-tion Control.Current edition published July 1,2012.Approved August 2012.Originallyapproved in 1992.Last previous edition approved in 2005 as F1372 93(2005).DOI:10.1520/F1372-93R12.2Available from National Institute of Standards and Technology,Gaithersburg,MD 20899.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.5 number of anomaliesthe total number of defects perphotomicrograph(see 10.1.1).3.1.6 particles that loosely adhereparticles in which over34of the bulk of the particle is above the plane of the surface.3.1.6.1 DiscussionThese particles 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).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 on 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 grains.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 removed 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 c