ASSESSMENT OF FERRITE IMPREGNATED PWBS AS A THERMAL TRANSFER MECHANISM FOR HIGH DENSITY/SPEED ELECTRONIC PACKAGING

THE TREND OF SYSTEM DESIGN AND DEVELOPMENT HAS BEEN TOWARD COMPACT, LOW POWER CONFIGURATIONS THAT ARE ACHIEVABLE THROUGH THE USE OF LARGE SCALE INTEGRATION (LSI) CIRCUITS AND INCREASED PACKAGING DENSITY. RECENT ADVANCES IN INTEGRATED CIRCUIT DEVICE TECHNOLOGIES HAVE INDICATED THAT LIMITATIONS EXIST WITH MANY OF THE CURRENT INTERCONNECTION TECHNOLOGIES. THEREFORE, CONCURRENTLY WITH THE GENERATION IF IC PACKAGING SOLUTIONS, THE TECHNOLOGICAL AREA OF THE PRINTED WIRING BOARD (PWB) CONFIGURATION MUST ALSO BE ADDRESSED. HIGH SPEED SYSTEM DESIGN PRESENTLY REQUIRE THE USE OF TRANSMISSION LINE THEORY IN THEIR LAYOUT. THE APPROACH PROPOSED HEREIN DEFINES AN APPROACH WHICH DOES NOT REQUIRE THE ROUTING OF MULTIPLE GROUND TRACES AND THUS PRODUCES A MUCH MORE EFFICIENT DESIGN. THE PROPOSED CONCEPT FOR A NEXT GENERATION PWB TECHNOLOGY WOULD STILL BE ABLE TO USE CURRENT PWB DESIGN RULE LAYOUTS FOR STANDARD PRINTED WIRING BOARDS. IN ADDITION, THE FERRITE IMPREGNATION OF THE PWB INNER LAYERS SHOULD PROVIDE A HEAT TRANSFER MECHANISM WITHOUT REQUIRING A HEAVY INTERNAL HEAT SINK.