Heat sink cooled power semiconductor device assembly having liquid metal interface

Claim 1

A HIGH PRESSURE-INTERFACE-FREE HEAT-PIPE COOLED POWER SEMICONDUCTOR DEVICE ASSEMBLY COMPRISING A PRESSURE-INTERFACE-FREE THIN INTEGRAL POWER SEMICONDUCTOR DEVICE-CUP MEMBER UNIT INCLUDING A POWER SEMICONDUCTOR DEVICE CONSISTING OF A BODY OF SEMICONDUCTOR MATERIAL DEFINED BY FIRST AND SECOND FLAT PARALLEL MAJOR SURFACES, FIRST AND SECOND THIN CUP-LIKE MEMBERS HAVING OUTER BOTTOM SURFACES RESPECTIVELY BONDED DIRECTLY TO THE FIRST AND SECOND FLAT PARALLEL SURFACES OF THE BODY OF SEMICONDUCTOR MATERIAL SO THAT THE INTEGRAL POWER SEMICONDUCTOR DEVICECUP MEMBER UNIT IS PRESSURE-INTERFACE-FREE, SAID CUP-LIKE MEMBERS FABRICATED OF A GOOD ELECTRICALLY AND THERMALLY CONDUCTIVE MATERIAL, AND CREEPAGE PATH LENGTHENING MEANS FORMED ALONG OUTER SIDE WALL PORTIONS OF SAID CUP-LIKE MEMBERS FOR INCREASING THE CREEPAGE PATH ACROSS SAID POWER SEMICONDUCTOR DEVICE, SAID POWER SEMICONDUCTOR DEVICE DEFINED AS DEVELOPING A THERMAL DENSITY OF AT LEAST 100 WATTS PER SQUARE INCH OF SURFACE AREA, A FIRST LONG NONWICKED GRAVITY-RETURN HEAT PIPE HAVING AN EVAPORATING SURFACE END WALL IN THERMAL CONTACT WITH AN INNER BOTTOM SURFACE OF SAID FIRST CUP-LIKE MEMBER FOR REMOVINMG HEAT THEREFROM, SAID FIRST NONWICKED GRAVITY-RETURN HEAT PIPES COMPRISING A FIRST ENCLOSED ELONGATED HOLLOW CHAMBER HAVING AN EVAPORATIO SECTION AT A FIRST END THEREOF RESPECTIVELY DEFINED BY THE EVAPORATING SURFACE END WALL AND A CONDENSER SECTION AT A SECOND END THEREOF REMOTE FROM THE FIRST END, AND A TWO-PHASE FLUID COOLANT CONTAINED WITHIN SAID FIRST CHAMBER AND BEING OF SUFFICIENT VOLUME IN THE LIQUID STATE TO CAUSE FULL IMMERSION OF AT LEAST THE HEATED PORTION OF THE EVAPORATING SURFACE, FIRST AND SECOND ELECTRICAL CONDUCTORS RESPECTIVELY CONNECTED TO SAID ASSEMBLY FOR SUPPLYING ELECTRICAL POWER TO SAID POWER SEMICONDUCTOR DEVICE, A STATIC FIRST THIN FILM OF A HIGH THERMAL AND ELECTRICAL CONDUCTIVITY METAL DISPOSED EXTERNAL OF SAID INTEGRAL SEMICONDUCTOR DEVICE-CUP MEMBER UNIT BETWEEN THE INNER BOTTOM SURFACE OF SAID FIRST CUP-LIKE MEMBER AND EVAPORATING SURFACE END WALL OF SAID FIRST HEAT PIPE AND IN WETTING CONTACT THEREWITH AND FORMING A STATIC FIRST THIN LIQUID METAL INTERFACE THEREBETWEEN DURING OPERATION OF SAID SEMICONDUCTOR DEVICE, SAID FIRST THIN FILM OF METAL OF THICKNESS IN THE RANGE OF 1/10 TO 5 MOLS, THE THIN LIQUID METAL INTERFACE NOT MECHANICALLY STRESSING THE THIN INTEGRAL POWER SEMICONDUCTOR DEVICE-CUP MEMBER UNIT AND THE HIGH THERMAL AND ELECTRICAL CONDUCTIVITY OF THE LIQUID METAL PERMITTING THE COOLING OF LARGE DIAMETER SEMICONDUCTOR DEVICES WITHOUT THE NEED FOR LARGE CLAMPING FORCES TO OBTAIN HIGH PRESSURE JOINTS BETWEEN SAID HEAT PIPE AND SAID THIN INTEGRAL POWER SEMICONDUCTOR DEVICE-CUP MEMBER UNIT, THE CLOSE SPACING BETWEEN THE FIRST HEAT PIPE AND HEAT-EMITTING POWER SEMICONDUCTOR DEVICE AND LACK OF PRESSURE INTERFACES THEREBETWEEN AND IN THE INTEGRAL POWER SEMICONDUCTOR DEVICE-CUP MEMBER UNIT SUBSTANTIALLY DECREASING THE STEADY-STATE THERMAL RESISTANCE AS WALL AS IMPROVING THE TRANSIENT RESPONSE OF THE HEAT-PIPE COOLED POWER SEMICONDUCTOR DEVICE ASSEMBLY TO OBTAIN IMPROVED SINGLE-SIDED COOLING OF THE DEVICE WITHOUT REQUIRING A COSTLY AND MECHANICALLY COMPLEX CLAMPING DEVICE, AND MEANS CONNECTED ONLY TO THE EVAPORATING SURFACE OF SAID FIRST HEAT PIPE FOR ENHANCING THE EVAPORATING SURFACE SO AS TO INCREASE THE RATE OF HEAT TRANSFER FROM THE FIRST CUP-LIKE MEMBER TO THE FLUID COOLANT IN SAID FIRST HEAT PIPE.