Reliability Evaluation of High Pin Count Hermetic Ceramic IC Packages for Space Applications

The results to date of a reliability testing program for the European Space Agency on high pin count hermetic ceramic packages are presented. The program commenced in 1988 and has the following objectives: • to determine the fundamental reliability, for space applications, of high pin count ceramic packages from manufacturers world wide; • to measure the thermal resistances and electrical parameters of these packages and to compare these with theoretically derived values; • to evaluate the reliability of different solder assembly techniques for high pin count, fine pitch, surface mount IC packages on printed circuit boards; • to work on the generation of specifications and guidelines for the selection and assembly of high pin count IC packages for space applications. Results are presented from work on: • application of scanning acoustic microscopy (SAM) to die attach and lid seal quality assessment; • the use of thermal characterization test chips and a computer controlled thermal resistance measurement system to measure thermal impedances of ceramic quad flat pack (CQFP) and ceramic pin grid array (CPGA) packages; • numerical prediction and practical measurement of electrical parasitics of CQFP and CPGA packages; • quality and reliability testing of CQFP and CPGA packages; • quality and reliability testing of 20 and 25-mil pitch surface mount solder assemblies of high pin count CQFP packages assembled on printed circuit boards.