Some Discussions on the Fixed Methods in Helium Mass Spectrum Leak Testing

The fixed methods of leak testing in testing method 1014.2 “Seal” from GJB 548B-2005 standards,divide the internal free volume of sealed packages into 5 ranges,each with a given condition for helium bombing and a corresponding reject limit R₁for the measured leak rate.As this ranges dividing is not sufficient,for some given internal free volume of sealed packages,the equivalent standard leak rate L is lenient with respect to that for the flexible methods,which is subject to the risk of miss testing for some fine leak components.Besides,for the ceramic packages with large cavity volume,helium bombing at the minimum pressure of 310 kPa for fixed methods may lead to the lid deflection,seal damage,etc.The difference of the equivalent standard leak rates between fix methods and flexible methods is analyzed,and the issues on the packages with large cavity during higher pressure of helium bombing,and the method with the lower pressure of helium bombing is also raised.