Thermal enhancement methods for ECL gate array packaging

Three different approaches used for thermal conductivity enhancement of emitter-coupled logic (ECL) gate array packaging are described. The approaches presented are: material substitution; package modification; and process modification. The method of thermal resistance measurement, the methods and process of modification of packaging, and the results of measurement are also described. Material substitution consisted of replacing the electrically conducting Cu-W alloy substrate with high thermal conductivity, electrically insulating inserts of BeO/AIN. This approach, though successful in achieving desired thermal enhancements, was not cost effective. Package modification together with process modification was needed to produce packages with thermal resistance less than 1° C/W and natural convection of less than 3° C/W at 1000 ft/min. Data at various air speeds from 250 to 1000 ft/min are presented for various thermal enhancement methods