1、ICS 29.045 Supersedes October 1987 edition.Prfung von Materialien fr die Halbleitertechnologie Bestimmung von Elementspuren in Flssigkeiten Teil 1:Silber (Ag), Gold (Au), Calcium (Ca), Kupfer (Cu), Eisen (Fe),Kalium (K) and Natrium (Na) in Salpetersure mittels AASIn keeping with current practice in
2、standards published by the International Organization for Standardization(ISO), a comma has been used throughout as the decimal marker.Ref. No. DIN 50451-1 : 2003-04English price group 06 Sales No. 010601.05DEUTSCHE NORM April 2003 No part of this translation may be reproduced without the prior perm
3、ission ofDIN Deutsches Institut fr Normung e.V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).Translation by DIN-Sprachendienst.In case of doubt, the German-language original should be consulted as the authoritative text.Determina
4、tion of trace elements in liquids for usein semiconductor technologyPart 1: Determination of calcium, copper, gold, iron, potassium, silverand sodium in nitric acid by atomic absorption spectrometryDocument comprises 4 pages.50451-1ForewordThis standard has been prepared by Technical Committee Prfun
5、g von Prozesschemikalien fr die Halb-leitertechnologie of the Normenausschuss Materialprfung (Materials Testing Standards Committee).AmendmentsThis standard differs from the October 1987 edition in that it has been revised in form and content.Previous editionDIN 50451-1: 1987-10.1 ScopeThis standard
6、 specifies a method of determining traces in nitric acid of calcium, copper, gold, iron, potas-sium, silver and sodium, in concentrations ranging from 0,1 ng/g to 50 ng/g, by means of graphite-furnaceatomic absorption spectrometry (AAS). This method may also be used to analyze other vaporizable liqu
7、idswhich have a percentage recovery between 75% and 125%.The presence of these metals is of relevance in the field of semiconductor technology.2 Normative referencesThis standard incorporates, by dated or undated reference, provisions from other publications. Thesenormative references are cited at t
8、he appropriate places in the text, and the titles of the publications arelisted below. For dated references, subsequent amendments to or revisions of any of these publicationsapply to this standard only when incorporated in it by amendment or revision. For undated references, thelatest edition of th
9、e publication referred to applies.DIN 8120-1 Terminology associated with weighing machines Classification Scales and balancesDIN 32645 Establishing the decision limit, detection limit and determination limit under repeatabilityconditions in chemical analysis Terminology, methods and evaluationDIN 38
10、406-29 German standard methods for the examination of water, waste water and sludge Cations(group E) Determination of 61 elements by inductively coupled plasma mass spectrometry(E 29)Page 2DIN 50451-1 : 2003-04DIN 51401-1 Atomic absorption spectrometry (AAS) TerminologySupplement 1to DIN 51401-1 Ato
11、mic absorption spectrometry (AAS) Terminology Explanatory notesDIN EN ISO 1042 Laboratory glassware One-mark volumetric flasks (ISO 1042 : 1998)DIN EN ISO 8655-2 Piston-operated volumetric apparatus Part 2: Piston pipettes(ISO 8655-2 : 2002)DIN EN ISO 14644-1 Cleanrooms and associated controlled env
12、ironments Part 1: Classification of air clean-liness (ISO 14644-1 : 1999)ISO 3696 : 1987 Water for analytical laboratory use Specification and test methodsASTM D 5127-99 Standard guide for ultra pure water used in the electronics and semiconductor industry1 Horwitz, W., Evaluation of analytical meth
13、ods used for regulation of foods and drugs. Anal. Chem., 1982: 54,6776A.2 Albert, R. and Horwitz, W., A heuristic derivation of the Horwitz curve. Anal. Chem., 1997: 69 (4), 789790.3 Concept3.1 High-purity waterFor the purposes of this standard, high-purity water is water which has been produced by
14、demineralizationfollowed by filtration or double distillation and which contains no more than 0,05 ng/g of the elements to bedetermined, i.e. Ag, Au, Ca, Cu, Fe, K and Na.NOTE: High-purity water as defined in ISO 3696 and ASTM D 5127-99 does not meet the requirements of thisstandard.4 UnitThe concen
15、tration of trace elements is to be expressed in ng/g.5 PrincipleAfter evaporating the liquid under examination to dryness under dust-free conditions, the residue is taken upin a mixture of nitric acid, hydrochloric acid (or ammonia solution, when determining silver) and high-puritywater, and analyze
16、d by means of graphite-furnace atomic absorption spectrometry. The ratio of the test portionmass to the relevant test solution mass after evaporation gives the enrichment factor.6 Reagents6.1 GeneralReagents shall not contain more than 0,5 ng/g of the elements to be determined. If the purity of comm
17、erciallyavailable reagents is inadequate, they shall be purified (e.g. by subboiling distillation).6.2 65% to 70% (m/m) nitric acid, HNO3.6.3 25% (m/m) ammonia solution, NH3.6.4 32% (m/m) hydrochloric acid, HCl.6.5 High-purity water, as in subclause 3.1.7 Apparatus and cleaning7.1 Apparatus7.1.1 Ato
18、mic absorption spectrometer, with graphite furnace atomizer, using argon as shield gas or purgegas, a radiation source appropriate for the metal to be determined, and an automatic sampler (cf. DIN 51401-1and Supplement 1 to DIN 50541-1).7.1.2 Vessel for evaporation (e.g. beaker or dish), having a vo
19、lume suitable for the test portion, of a contami-nant-free material as specified in DIN 38406-29, for example (preferably perfluoro alkoxyl alkane), and cleanedas in subclause 7.2.7.1.3 Vessels for sample changer, of a contaminant-free material as specified in DIN 38406-29, for example(preferably pe
20、rfluoro alkoxyl alkane), and cleaned as in subclause 7.2.Page 3DIN 50451-1 : 2003-047.1.4 Precision balance (cf. DIN 8120-1).7.1.5 Closable wide-neck containers, for gravimetrically prepared calibration solutions, of a material asspecified in DIN 38406-29, for example, and cleaned as in subclause 7.
21、2.7.1.6 Volumetric flasks, for volumetrically prepared calibration solutions, of a material as specified inDIN 38406-29, for example, and cleaned as in subclause 7.2.NOTE: See DIN EN ISO 1042 for accuracy classes of flasks.7.1.7 Piston-operated pipettes, of nominal capacities between 10 l and 1 000
22、l, as in DIN EN ISO 8655-2.Tips shall be cleaned as in subclause 7.2, item a).7.1.8 Equipment for evaporating liquids to dryness under dust-free and contaminant-free conditions, asspecified in DIN EN ISO 14644-1, of at least ISO Class 5.7.2 CleaningVessels, flasks and pipette tips are to be cleaned
23、either bya) leaving the apparatus to stand in a solution containing equal parts of nitric acid (as in subclause 6.2) andhigh-purity water for about 24 hours and then thoroughly rinsing with high-purity water (the cleaning timefor pipette tips may be reduced to one hour), orb) evaporating nitric acid
24、 (as in subclause 6.2) in the apparatus for at least one hour and then rinsingthoroughly with high-purity water. This method may not be used for pipette tips.Other suitable cleaning methods may be used.When determining gold, after cleaning as specified above, leave the apparatus to stand in a soluti
25、on containingtwo parts by volume of nitric acid (as in subclause 6.2) and one part by volume of hydrochloric acid (as insubclause 6.4) for at least one hour at 40 C to 60 C, and then rinse with high-purity water.8 SamplingFrom each sample, at least three test portions (i.e. i 3) shall be taken for p
26、arallel determinations.The test portion mass, mP, shall be such that, after evaporation, the lowest measurable concentration of thetrace element under examination lies above the determination limit. This limit is to be determined as specifiedin DIN 32645 using a blank solution (cf. DIN 51401-1 and S
27、upplement 1 to DIN 50541-1) as specified inclause 10 of the present standard. Each test portion (normally about 10 g to 200 g) is to be weighed into theevaporation vessel, with an uncertainty of measurement no greater than 5%.9 Sample pretreatment9.1 Evaporate a test portion in a vessel as in subcla
28、use 7.1.2 under dust-free conditions and avoiding anyuncontrolled loss of sample material.9.2 Heat the vessel to about 80 C and take up the residue first with 100 l to 500 l of nitric acid (dependingon the size of the test portion and the interior diameter of the vessel), and then with 50 l to 250 l
29、 of hydrochloricacid. If iron or gold will not be determined, then hydrochloric acid need not be added. When determining silver,ammonia solution (as in subclause 6.3) is to be used in place of nitric acid and hydrochloric acid.Ensure that the entire vessel bottom is in contact with the acid mixture
30、up to the time the residue has fullydissolved. Add 1 ml to 5 ml of high-purity water and mix by gently swirling. Determine the mass, mML, of thesolution obtained (referred to below as test solution) to an accuracy of 5% either by measuring the quantityof reagents and water added or by weighing. Usin
31、g a piston-operated pipette, transfer the necessary quantityof test solution to the sample changer.10 Preparation of blank solutionsTo establish the determination limit, prepare at least three blank solutions using the procedure specified inclause 9, but without transferring the solutions to the sam
32、ple changer.11 Procedure11.1 MeasurementAdjust the spectrometer according the manufacturers instructions and use the following wavelengths todetermine the trace elements in each test solution and in the blank solutions.Page 4DIN 50451-1 : 2003-04lAu= 242,8 nmlAg= 328,1 nmlCa= 422,7 nmlCu= 324,7 nmlF
33、e= 248,3 nmlK= 766,5 nmlNa= 589,0 nmCarry out at least three measurements (i.e. n 3) for each test solution.11.2 CalibrationCalibrate the spectrometer using a standard method (cf. DIN 51401-1 and Supplement 1 to DIN 50541-1),taking an aqueous reference solution which contains the element to be deter
34、mined and which has the same acidconcentrations (nitric acid and, where relevant, hydrochloric acid) or, when determining silver, the sameammonia solution concentration as the test solution. Calibrations shall be carried out after the spectrometerhas been adjusted and immediately prior to measuremen
35、t.The aqueous reference solution need not have the same acid concentration, if the accuracy of results will notbe significantly influenced by this.12 Calculation and expression of resultsThe enrichment factor, fi, for each test portion shall be determined using equation (1):mPifi= (1)mMLiwith i = 1,
36、 2, ., nwheremPiis the test portion mass, in g;mMLiis the test solution mass, in g.Calculate the arithmetic mean of the n values obtained for each element in the test solution, Ei. To convert theresults into concentrations for each element, divide the mean, Ei, by the relevant enrichment factor, fi.
37、Calculate the mean of the blank values, L, in the same manner, using the average value of the enrichmentfactors.After subtracting L from Ei, take the total mean for each element to be determined, expressed as a content bymass (m/m), giving either the repeatability standard deviation, sr, or the medi
38、an and the half-range, R/2.13 PrecisionInterlaboratory testing for Ag, Au and Cu yielded a reproducibility coefficient of variation between 10% and30% for a concentration of 5 ng/g, and a coefficient between 10% and 20% for a concentration of 30 ng/g. ForCa, Cu and Fe, a reproducibility coefficient
39、of variation between 20% and 30% was obtained for concentrationsranging from 0,5 ng/g to 1 ng/g. 1 and 2Experience has shown that a comparable precision of method can be assumed when analyzing other liquids.14 Test reportThe test report shall refer to this standard and include the following informat
40、ion:a) description of sample;b) type of spectrometer used and its parameters;c) mass of test portions (mPi) and of test solutions (mMLi), and enrichment factors (fi);d) number of test portions (i);e) number of blank solutions (k);f) mean of blank values (L);g) total mean for each element (calculated as in clause 12), and the repeatability standard deviation, sr, orthe median and the half-range, all expressed in ng/g;h) any deviations from this standard;i) tester, test date and location.
