Semiconductor Measurement Technology: The Use of Acoustic Emission to Determine the Integrity of Large Kovar Glass-Sealed Microelectronic Packages

摘要

The general objective of this research was to develop tests to determine the integrity of large hybrid packages under various thermal and mechanical stresses that may be encountered during assembly, during installation in systems, or in operation. Several measurement techniques were investigated, but emphasis was placed on acoustic-emission test procedures. The accomplishments were: (1) The effects of avionics environmental vibration on the seals of hybrid packages mounted on printed-circuit (PC) boards were determined. A major conclusion of this section was that lead fatigue failure occurs before seal damage on packages from high quality lots. (2) A small acoustic-emission detector was developed that is sensitive to surface waves, but relatively insensitive to vibration induced cable noise. (3) A high-temperature (125C) open-package helium leak test method was successfully developed to observe marginal seal damage. (4) An acoustic-emission test for inspection of hybrid packages during high-temperature thermal shock was developed. (5) A study of possible damage to seals during thermocompression and thermosonic bonding, during lead forming, and during other assembly operations was carried out.