Test chips, test systems and thermal test data for multichip modules in the ESPRIT-APACHIP project

This paper presents details of four multichip module cooling techniques using common test chips and test methods in the ESPRIT Project 2075, APACHIP. The project is concerned with the development of technology and manufacturing capabilities for single-chip packages and multichip modules. The paper presents descriptions and test results of cooling techniques investigated for multichip modules. These include heat-pipes (Bull), immersion in inert fluid (GEC-Marconi), water-cooled thin membrane (GEC-Marconi) and direct-chip on water-cooled cold plate (Siemens Nixdorf Informationssysteme AG). Two 12 mm square thermal test chips are described which have been developed (NMRC) for characterisation of thermal demonstrators. Test systems, established at four partner sites for diode temperature sensor calibration and thermal characterisation of demonstrators are described and compared. Statistical errors amounted to less than ±1%. Systematic errors were less than ±10%. The thermal test data has enabled the project partners to compare the various cooling methods in terms of current and future system designs and to make decisions as to which system is most appropriate from both a technical and economic viewpoint.