ASTM_D_7980_-_15.pdf

Designation:D798015Standard Guide forIon-Chromatographic Analysis of Anions in Grab Samplesof Ultrapure Water(UPW)in the Semiconductor Industry1This standard is issued under the fixed designation D7980;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.1.Scope1.1 This guide applies to ultrapure water that is thought tocontain low ppt(parts-per-trillion,weight/weight)levels ofanionic contaminants(for example,bromide,chloride,fluoride,nitrate,nitrite,phosphate,and sulfate).To minimize carry-overproblems between analyses,it is best to limit the concentrationof any one contaminant to approximately 200 ppt(althoughthis limit is only an approximation and may vary,depending onthe users application).1.2 This guide is intended to help analysts avoid contami-nation of ultrapure-water samples,since contamination controlis the primary challenge when quantifying ppt-level anions ingrab samples.1.3 This guide does not include recommendations for col-lecting samples from the water source.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-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD5127 Guide for Ultra-Pure Water Used in the Electronicsand Semiconductor Industries3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminology D1129.3.2 Acronyms:3.2.1 HDPE,nhigh-density polyethylene3.2.2 IC,nion chromatograph3.2.3 PEEK,npolyether ether ketone3.2.4 ppb,nparts-per-billion(weight/weight)3.2.5 ppt,nparts-per-trillion(weight/weight)3.2.6 UPW,nultrapure water4.Significance and Use4.1 This guide is intended to help analysts in the semicon-ductor industry.Examples of the usefulness of anion monitor-ing include:(1)determining when ion-exchange resin beds(inwater-purification systems)need to be regenerated,and(2)ensuring that anion levels are low enough to allow the water tobe used for the manufacture of semiconductor devices.4.2 To ensure that the anions are indeed at low-ppt levels,itis recommended to check the conductivity of a subsamplebefore proceeding with Section 5 of this guide.This check doesnot need to be exact;its purpose is simply to let the analystknow if the conductivity is higher than that of the highest-levelstandard solution being tested.Any high reading signifies thatthe sample,if analyzed,might contaminate the instrument.5.Guidelines5.1 General Considerations:5.1.1 In working with grab samples of ultrapure water,concentrate on controlling contamination,which is the over-riding challenge when analyzing for anions in UPW.Precau-tions must be taken,including the following.Wear gloves(forexample,nitrile)that do not shed anions.Do not touchanything that might contact the samples.Minimize anioniccontamination in the laboratory air;for example,do not workin the same lab where concentrated mineral acids are beingused or where acid fumes might be brought in by means of theventilation system.5.1.2 Use only fresh,running-from-the-tap UPW wheneverwater is needed.For guidelines regarding maximum contami-nation levels allowed in this water,consult Guide D5127;recommendations are based on the type of semiconductordevice that ultimately is involved.To ensure highest purity and1This guide is under the jurisdiction of ASTM Committee D19 on Water and isthe direct responsibility of Subcommittee D19.05 on Inorganic Constituents inWater.Current edition approved Feb.15,2015.Published March 2015.DOI:10.1520/D7980-15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 minimize the build-up of contamination,keep the water streamflowing at all times(a slow rate is acceptable when the waterstream is not in use).5.2 Ion Chromatograph(IC):5.2.1 Use caution in selecting the IC that will be used forthese analyses.While an entirely new instrument is notmandatory,a unit that has been used for,for example,parts-per-million-level samples often needs extensive clean-up be-fore the anion levels are acceptably low.When utilizing such“used”chromatographs,replace all tubing with new lengthsand clean the Load/Inject valve thoroughly with fresh,running-from-the-tap UPW;in some cases,the internal parts of thisvalve will need to be replaced with new ones.5.2.2 Use new PEEK(polyether ether ketone)tubing toplumb the instrument.5.2.3 Use a l