Method of Making a Low Profile Flip Chip Power Module

Abstract

A power module is proposed to package an electronic system having flip chip power MOSFET devices. The power module includes a front surface cover board and a multi-layer printed circuit laminate bonded thereto. Notably, the front surface of the printed circuit laminate includes recessed pockets each having printed circuit traces atop its floor. Inside the recessed pockets are power MOSFET and other circuit components bonded to the printed circuit traces. As the circuit components are encased inside the power module, it features a low profile, an increased mechanical robustness and EMI/RFI immunity. Additionally, some circuit components can be provided with a front-side bonding layer that is also bonded to the front surface cover board to realize a double-side bonding to the interior of the power module. Methods for making the low profile power module are also described.

1 . A method of making a low profile power module that encases a plurality of circuit components, the method comprising:
 A) forming a multi-layer printed circuit laminate having:
 (1) a plurality of bonded printed circuit layers each having a circuit forming means thereon; and, 
 (2) along the front surface of the multi-layer printed circuit laminate:
 (2a) a plurality of recessed pockets each having the circuit forming means atop its floor; and 
 (2b) a plurality of circuit components, located inside the plurality of recessed pockets, each having a back-side component bonding means that is conductively bonded to the circuit forming means; 
 
   B) providing an electrically conductive front surface cover board; and   C) physically and electrically bonding the front surface of the multi-layer printed circuit laminate to a back surface of the front surface cover board.   
     
     
         2 . The method of making a low profile power module of  claim 1  wherein forming a multi-layer printed circuit laminate further comprising:
 A1) forming the plurality of bonded printed circuit layers each having a circuit forming means thereon; 
 A2) along the front surface of the plurality of bonded printed circuit layers, creating the plurality of recessed pockets by selectively removing a corresponding plurality of material pockets from a corresponding number of layers of printed circuit layers; 
 A3) placing the plurality of circuit components inside the plurality of recessed pockets; and 
 A4) conductively bonding the plurality of circuit components, via their back-side component bonding means, to the circuit forming means. 
 
     
     
         3 . The method of making a low profile power module of  claim 1  wherein forming a multi-layer printed circuit laminate further comprising:
 A1) providing a number, according to the layer requirement of the multi-layer printed circuit laminate, of printed circuit layers each having a circuit forming means thereon; 
 A2) for each printed circuit layer, determining and pre-cutting out a specific number of windows each of a specific geometry such that, upon later lamination, the number of printed circuit layers would form said plurality of recessed pockets; 
 A3) stacking and laminating the number of printed circuit layers hence simultaneously forming said plurality of recessed pockets; 
 A4) creating, if necessary as specified by the multi-layer printed circuit laminate, additional circuit forming means on each of the number of laminated printed circuit layers; 
 A5) placing the plurality of circuit components inside the plurality of recessed pockets; and 
 A6) conductively bonding the plurality of circuit components, via their back-side component bonding means, to the circuit forming means. 
 
     
     
         4 . A method of making a low profile power module that encases a plurality of circuit components, the method comprising:
 A) providing an electrically conductive front surface cover board;   B) forming a multi-layer printed circuit laminate having:
 (1) a plurality of bonded printed circuit layers each having a circuit forming means thereon; and, 
 (2) along the front surface of the multi-layer printed circuit laminate:
 (2a) a plurality of recessed pockets each having the circuit forming means atop its floor; and 
 (2b) a plurality of circuit components, located inside the plurality of recessed pockets, each having a front-side component bonding means that is capable of being conductively bonded to the front surface cover board and a back-side component bonding means that is conductively bonded to the circuit forming means; and 
 
   C) physically and electrically bonding both the front surface of the multi-layer printed circuit laminate and all the front-side component bonding means to the front surface cover board.   
     
     
         5 . The method of making a low profile power module of  claim 4  wherein providing an electrically conductive front surface cover board further comprises using a front surface cover board material that is heat conductive whereby facilitate heat dissipation from said plurality of circuit components.