ASTM_F_979_-_86_2003.pdf

Designation:F 979 86(Reapproved 2003)Standard Test Method forHermeticity of Hybrid Microcircuit Packages Prior toLidding1This standard is issued under the fixed designation F 979;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 The hermetic integrity of hybrid microcircuit packagesis an important material or parts acceptance requirement.Determination of this parameter should be made before thehybrid circuit is assembled and sealed inside the package.1.2 This test method covers a test for leaks in a package thatis intended to be hermetically sealed after hybrid circuitassembly.Various types of hybrid packages may be tested bythis test method.The test method is nondestructive andtherefore suitable for 100%inspection.1.3 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2.Referenced Documents2.1 ASTM Standards:2F 78 Test Method for Calibration of Helium Leak Detectorsby Use of Secondary StandardsF 134 Test Methods for Determining Hermeticity of Elec-tron Devices with a Helium Mass Spectrometer LeakDetector32.2Federal Standard:Fed.Std.No.209Clean Room and Work Station Require-ments,Controlled Environment43.Summary of Method3.1 The specimen package is placed on an elastomer surfacewith the inside cavity of the package facing an orifice in theelastomer.This orifice is an opening to the vacuum section ofa mass spectrometer leak detector.Helium gas,to which themass spectrometer is sensitive,is flooded over the outside ofthe package.Indication of a leak is detected by suitableinstrumentation on the mass spectrometer.4.Significance and Use4.1 Hermeticity test methods,for example,Test MethodsF 134,deal with sealed packages only and do not apply directlyto unsealed packages.This test method is most applicable fordetermining the hermeticity of a package before it has beensealed with a lid or a cover.Packages that are intended forhermetic seal use are manufactured so as to prevent leakage ofhelium at a rate in excess of 1 3 108atm cc/s under apressure differential of 1 atm when tested on a helium massspectrometer leak detector.This test should be conducted in aclean work area such as would be provided by a laminar flowclean bench as specified in Fed.Std.No.209.This test methodis not recommended for use in commerce until the precisionhas been determined.4.2 Acceptance and rejection criteria for this test methodshall be agreed upon by the purchaser and the supplier as partof the purchase contract.NOTE1Packages that are not capable of meeting a maximum leakrate of 1 3 108atm cc/s of helium at a pressure differential of 1 atm arecustomarily rejected on the basis that good quality assurance is achievedwith this performance level.5.Apparatus5.1 Fixtures and Fittings,suitable for vacuum apparatusapplications that will properly fit to the input plumbing on themass spectrometer and hold the package style of interest on theseal gasket(see Fig.1).5.2 Surgical Rubber Gasket,or equivalent that has a surfacedimension matching that of the seal ring on the packagespecimen.5.3 Vacuum Grease.55.4 Helium Mass Spectrometer Leak Detector,with a detec-tion sensitivity of one part of helium in ten million parts of air1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.03 on MetallicMaterials.Current edition approved March 27,1986.Published June 1986.2For 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.3Discontinued;see l996 Annual Book of ASTM Standards,Vol 10.04.4Available from Standardization Documents Order Desk,Bldg.4 Section D,700Robbins Ave.,Philadelphia,PA 19111-5094,Attn:NPODS.5The sole source of supply of vacuum grease,Apiezon Type M or N known tothe committee at this time is Miconite Ltd.,P.O.Box 136 Manchester,M601AN,England,U.K.If you are aware of alternative supppliers,please provide thisinformation to ASTM Headquarters.Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.at a manifold pressure of 0.2 m Hg(0.0267 Pa).The minimumdetectable leak rate of this apparatus should be 5 3 1011atmcc/s for helium gas.NOTE2Additional technical information on leak detecting with thehelium mass spectrometer is provided in Test Methods F 134.Infor