A Recommendation of Thermal Measurement Techniques for IC Chips and Packages

New techniques and nomenclature are recommended to provide fast, repeatable and meaningful thermal characteristics for IC chips and packages. Techniques for measuring thermal resistance and temperature responses curves, including MIL-STD-883 Method 1012 (Thermal Characteristics), were evaluated to determine improved methods of measuring MIL-M-38510 microelectronic packages. Problems and solutions associated with the present test methods are described. Computer simulations, infrared measurements and electrical (temperature sensitive parameter) measurements on special thermal test packages were used as the basis for evaluations and comparisons. A difference of about 5:1 was shown to exist for the thermal resistance values of the Junction Peak, Junction Average and Junction Region, as measured relative to the Chip Carrier. Based on these results, a new Method 1012 has been recommended.1 This method enables the user to make direct comparisons between thermal data provided by different vendors; moreover, the data provides a meaningful interface for integrating vendor's data into the thermal design of the user's electronic system.