ASTM F1845-2008 Standard Test Method for Trace Metallic Impurities in Electronic Grade Aluminum-Copper Aluminum-Silicon and Aluminum-Copper-Silicon Alloys by High-Mass-Resolution G.pdf

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1、Designation: F 1845 08Standard Test Method forTrace Metallic Impurities in Electronic Grade Aluminum-Copper, Aluminum-Silicon, and Aluminum-Copper-SiliconAlloys by High-Mass-Resolution Glow Discharge MassSpectrometer1This standard is issued under the fixed designation F 1845; the number immediately

2、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.1. Scope1.1 This test me

3、thod determines the concentrations of tracemetallic impurities in high purity (99.99 wt. % pure, or purer,with respect to metallic trace impurities) aluminum-copper,aluminum-silicon and aluminum-copper-silicon alloys withmajor alloy constituents as follows:aluminum Greater than 95.0 %copper Less or

4、equal than 5.0 %silicon Less or equal than 5.0 %1.2 This test method pertains to analysis by magnetic-sectorglow discharge mass spectrometer (GDMS).1.3 This test method does not include all the informationneeded to complete GDMS analyses. Sophisticated computer-controlled laboratory equipment, skill

5、fully used by an experi-enced operator, is required to achieve the required sensitivity.This test method does cover the particular factors (for example,specimen preparation, setting of relative sensitivity factors,determination of detection limits, etc.) known by the respon-sible technical committee

6、 to effect the reliability of high purityaluminum analyses.1.4 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-bi

7、lity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE 1593 Guide for Assessing the Efficacy of Air Care Prod-ucts in Reducing Sensorly Perceived Indoor Air MalodorIntensity3. T

8、erminology3.1 Terminology in this test method is consistent withTerminology E 135. Required terminology specific to this testmethod, not covered in Terminology E 135, is indicated in 3.2.3.2 Definitions:3.2.1 campaigna test procedure to determine the accuracyof the instrument, which was normally per

9、formed at thebeginning of the day or after the instrument modification, orboth.3.2.2 reference samplematerial accepted as suitable foruse as a calibration/sensitivity reference standard by all partiesconcerned with the analyses.3.2.3 specimena suitably sized piece cut from a referenceor test sample,

10、 prepared for installation in the GDMS ionsource, and analyzed.3.2.4 test samplematerial (aluminum alloy) to be ana-lyzed for trace metallic impurities by this GDMS method.3.2.4.1 DiscussionGenerally the test sample is extractedfrom a larger batch (lot, casting) of product and is intended tobe repre

11、sentative of the batch.4. Summary of Test Method4.1 A specimen is mounted in a plasma discharge cell.Atoms subsequently sputtered from the specimen surface areionized, and then focused as an ion beam through a double-focusing magnetic-sector mass separation apparatus. The massspectrum (the ion curre

12、nt) is collected as magnetic field oracceleration voltage, (or both) is scanned.4.2 The ion current of an isotope at mass Miis the totalmeasured current, less contributions from all other interferingsources. Portions of the measured current may originate fromthe ion detector alone (detector noise).

13、Portions may be due to1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.17 on SputterMetallization.Current edition approved June 15, 2008. Published July 2008. Originallyapproved in 1997. Last previous edition approve

14、d in 2002 as F 1845 97(02).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

15、 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.incompletely mass resolved ions of an isotope or molecule withmass close to, but not identical with, Mi. In all such instancesthe interfering contributions must be estimated and subtractedfrom the measured signal.4.2.1

16、If the source of interfering contributions to the mea-sured ion current at Micannot be determined unambiguously,the measured current less the interfering contributions fromidentified sources constitutes an upper bound of the detectionlimit for the current due to the isotope.4.3 The composition of th

17、e test specimen is calculated fromthe mass spectrum by applying a relative sensitivity factor(RSF(X/M) for each contaminant element, X, compared to thematrix element, M. RSFs are determined in a separate analysisof a reference material performed under the same analyticalconditions, source configurat

18、ion, and operating protocol as forthe test specimen.4.4 The relative concentrations of elements X and Y arecalculated from the relative isotopic ion currents I (Xi) and I(Yj) in the mass spectrum, adjusted for the appropriate isotopicabundance factors (A (Xi), A (Yj) and RSFs. I (Xi) and I (Yj)refer

19、 to the measured ion current from isotopes Xiand Yj,respectively, of atomic species X and Y as follows:X!/Y!5RSFX/M!/RSFY/M!3AYj!/AXi! 3 IXi!/IYj! (1)where (X)/(Y) is the concentration ratio of atomic species Xto species Y. If species Y is taken to be the aluminum matrix(RSF (M/M) = 1.0), (X) is (wi

20、th only very small error for puremetal matrices) the absolute impurity concentration of X.5. Significance and Use5.1 This test method is intended for application in thesemiconductor industry for evaluating the purity of materials(for example, sputtering targets, evaporation sources) used inthin film

21、 metallization processes. This test method may beuseful in additional applications, not envisioned by the respon-sible technical committee, as agreed upon between the partiesconcerned.5.2 This test method is intended for use by GDMS analystsin various laboratories for unifying the protocol and param

22、etersfor determining trace impurities in aluminum-copper,aluminum-silicon, and aluminum-copper-silicon alloys. Theobjective is to improve laboratory-to-laboratory agreement ofanalysis data. This test method is also directed to the users ofGDMS analyses as an aid to understanding the determinationmet

23、hod, and the significance and reliability of reported GDMSdata.5.3 For most metallic species the detection limit for routineanalysis is on the order of 0.01 wt. ppm. With specialprecautions, detection limits to sub-ppb levels are possible.5.4 This test method may be used as a referee method forprodu

24、cers and users of electronic-grade aluminum-copper,aluminum-silicon and aluminum-copper-silicon materials.6. Apparatus6.1 Glow Discharge Mass Spectrometer, with mass resolu-tion greater than 3500, and associated equipment and supplies.The GDMS must be fitted with an ion source specimen cell thatis c

25、ooled by liquid nitrogen, Peltier cooled, or cooled by anequivalent method.6.2 Machining Apparatus, capable of preparing specimensand reference samples in the desired geometry and with smoothsurfaces.6.3 Electro-Polishing Apparatus, capable of removing thecontaminants from the surfaces of specimens.

26、7. Reagents and Materials7.1 ReagentsReagent and high purity grade reagents asrequired (MeOH, HNO3and HCl).7.2 Demineralized Water.7.3 Tantalum Reference Sample.7.4 Aluminum Reference Sample.7.4.1 To the extent available, aluminum reference materialsshall be used to produce the GDMS relative sensiti

27、vity factorsfor the various elements being determined (see Table 1).7.4.1.1 As necessary, non-aluminum reference materialsmay be used to produce the GDMS relative sensitivity factorsfor the various elements being determined.7.4.2 Reference materials should be homogeneous (see11.1) and free of cracks

28、 or porosity.7.4.3 At least two reference materials are required to estab-lish the relative sensitivity factors, including a 99.9999 % purealuminum metal to establish the background contribution inanalyses.7.4.4 The concentration of each analyte for relative sensi-tivity factor determination should

29、be at a factor of 100 greaterthan the detection limit determined using a 99.9999 % purealuminum specimen, but less than 100 ppmw.7.4.5 To meet expected analysis precision, it is necessarythat specimens of reference and test material present the samesize and configuration (shape and exposed length) i

30、n the glowdischarge ion source, with a tolerance of 0.2 mm in diameterand 0.5 mm in the distance of sample to cell ion exit slit.8. Preparation of Reference Standards and TestSpecimens8.1 The surface of the parent material must not be includedin the specimen.8.2 The machined surface of the specimen

31、must be cleanedby electropolishing or etching immediately prior to mountingthe specimen and inserting it into the glow discharge ionsource.TABLE 1 Suite of Impurity Elements to Be AnalyzedANOTEEstablish RSFs for the following suite of elements:silver arsenic gold boron beryllium calcium cerium chrom

32、ium cesium copper ironpotassium lithium magnesium manganese sodium nickel phosphorus antimony silicon tin thoriumtitanium uranium vanadium zinc zirconiumAAdditional species may be determined and reported, as agreed upon between all parties concerned with the analyses.F18450828.2.1 In order to obtain

33、 a representative bulk composition ina reasonable analytical time, surface cleaning must remove allcontaminants without altering the composition of the specimensurface.8.2.2 To minimize the possibility of contamination, cleaneach specimen separately immediately prior to mounting in theglow discharge

34、 ion source.8.2.3 Prepare and use electropolishing or etching solutionsin a clean container insoluble in the contained solution.8.2.3.1 Electropolishingperform electropolishing in asuitable electropolishing solution (2:1 MeOH:HNO3was foundapplicable). Apply 5 to 15 V (dc) across the cell, with thesp

35、ecimen as anode. Electropolish to expose smooth, cleanmetal over the entire polished surface.8.2.3.2 Etchingperform etching by immersing the speci-men in suitable acid mixture solution (4:1:1 H2O:HF:HNO3was found applicable). Etch the specimen until smooth, cleanmetal is exposed over the entire surf

36、ace.8.3 Immediately after cleaning, wash the specimen withseveral rinses of high purity methanol, or other high purityreagent able to remove water from the specimen surface, anddry the specimen in the laboratory environment.8.4 Immediately mount and insert the specimen into theglow discharge ion sou

37、rce, minimizing exposure of thecleaned, rinsed and dried specimen surface to the laboratoryenvironment.8.4.1 As necessary, use a noncontacting gage when mount-ing specimens in the analysis cell specimen holder to ensurethe proper sample configuration in the glow discharge cell (see7.4.5).8.5 Sputter

38、 etch the specimen surface in the glow dischargeplasma for a period of time before data acquisition to ensurethe cleanness of the surface (see 12.3). Pre-analysis sputteringconditions are limited by the need to maintain sample integrity.Pre-analysis sputtering at twice the power used for analysissho

39、uld be adequate for sputter etch cleaning.9. Preparation of the GDMS Apparatus9.1 Reference to Test Method F 1593, Section 9.10. Instrument Quality Control10.1 Reference to Test Method F 1593, Section 10.11. Standardization11.1 The GDMS instrument should be standardized usingNIST traceable reference

40、 materials, preferably aluminum to theextent such reference samples are available.11.1.1 RSF values should, in the best case, be determinedfrom the ion beam ratio measurements of four randomlyselected specimens from each standard required, with fourindependent measurements of each pin.11.1.2 RSF val

41、ues must be determined for the suite ofimpurity elements for which specimens are to be analyzed (seeTable 1) using selected isotopes for measurement and RSFcalculation (see Table 2).12. Analysis Procedure12.1 Establish a suitable data acquisition protocol (DAP)appropriate for the GDMS instrument use

42、d for the analysis.12.1.1 The protocol must include, but is not limited to, themeasurement of elements tabulated in Table 1 and isotopestabulated in Table 2 for respective matrix. Annex A1 listssignificant spectral interferences in this testing.12.1.2 Instrumental parameters selected for isotope mea

43、-surements must be appropriate for the analysis requirements:(a) ion current integration times to achieve desired precisionand detection limits; (b) mass ranges about the analyte masspeak over which measurements are acquired to clarify massinterferences.12.2 Insert the prepared specimen into the GDM

44、S ionsource, allow the specimen to cool to source temperature, andinitiate the glow discharge at pre-analysis sputtering condi-tions.12.3 After at least 5 min of pre-analysis sputtering, adjustthe glow discharge ion source sputtering conditions to theconditions required for analysis, ensuring that t

45、he gas pressurerequired to do so is within normal range.12.4 Analyze the specimen using the DAP protocol andaccept as final the concentration values determined only asdetection limits.12.5 Generate a MDAP protocol including only the ele-ments determined to be present in the sample (from results of12

46、.4).12.6 Measure the sample at least two additional times (withat least 10-min intervals between the measurements) using theMDAP protocol until the criteria of 12.6.1 is met.12.6.1 If the concentration differences between the last twomeasurements are less than 5, 10 or 20 %, depending onTABLE 2 Isot

47、ope SelectionANOTEUse the following isotopes for establishing RSF values and forperforming analyses on test specimens.Aluminum-Copper Aluminum-SiliconAluminum-Copper-SiliconSilver 109 109 109Arsenic 75 75 75Gold 197 197 197Boron 11 11 11Beryllium 9 9 9Calcium 44 44 44Cerium 140 140 140Chromium 52 52

48、 52Cesium 133 133 133Copper 65 65 65Iron 56 56 56Potassium 39 39 39Lithium 7 7 7Magnesium 24 24 24Manganese 55 55 55Sodium 23 23 23Nickel 58 60 60Phosphorus 31 31 31Antimony 121 121 121Silicon 28 28 28Tin 124 119 124Thorium 232 232 232Titanium 48 48 48Uranium 238 238 238Vanadium 51 51 51Zinc 66 66 6

49、6Zirconium 94 90 94AThis selection of isotopes minimizes significant interferences. Additionalspecies may be determined and reported, as agreed upon between all partiesconcerned with the analyses.F1845083concentration (Table 3), the measurements are confirmed andthe last two measurements are averaged.12.7 The confirmed values from 12.6 and the detectionlimits determined from 12.4 are reported together as the resultof the analysis.13. Detection Limit Determination13.1 Reference to Test Method F 1593, Section 13.14. GDMS Analysis for Thorium, Uranium and SimilarEl