Study On Removal Of Helium Adsorption Method Of Sealing Test Of Electronic Components

With rapid development of packaging technology, plastic package has been widely usedin high reliability application. However, the military used microelectronic devices are mainlypacked by ceramics, glass and metal materials because the packages are usually vacuumsealed to meet the higher performance requirements. The internal structure of microelectronicdevice is précising, and is very sensitive to moisture and ion pollution as well. This pollutionnot only changes the surface state of the device, but also degradates the device performance.The heavy corrosion on the internal structure of components can even result in fatal failure toopen. Hence the sealing performance will have a direct impact on product performance.Therefore, it is important significant to the assurance of high reliability devices for the studyof the leak test.In sealing test standard of GJB548B, GJB360B and GJB128A, it is clearly defined thatthe sample taken from the pressure box should remove adsorption from sample surface, butthe standard does not explain how to remove of the helium adsorption. This work is to studythe microelectronic device helium leak test process by use of mass spectrometer, to explorehow to remove the helium adsorption as the device takes out from vacuum pressure box, totest the sealing performance of the microelectronic package, and hence to meet therequirements of the testing standard. In the study, the combination sealing test of a number ofdifferent packaging materials and packed devices were studied, and a lot of helium adsorptiondata were collected, summarized and analyzed. The formula if molecular flowing is simplified.Through strict mathematical derivation, the extreme detection parameter is determined. Basedon the experiment data and standard requirement, the "principle of choosing fixed method andthe flexible method” was suggested. And then the high temperature baking process and airflow method for effective removal of helium adsorption on this basis were verified, and hencethe testing standards were improved and the common difficult problem on detection andremoval of helium in industry was solved.