Inter-circuit encapsulated packaging

Abstract

An encapsulated circuit assembly and a method for making an encapsulated circuit assembly are disclosed. The assembly comprises a first printed circuit board, a second printed circuit board, and a heat transfer device. The second printed circuit board comprises a heatsink, and the heat transfer device couples between a device mounted on the first printed circuit board and the second printed circuit board for transferring heat from the device to the heatsink of the second printed circuit board.

What is claimed is:  
     
         1 . A printed circuit board assembly, comprising: 
 a first printed circuit board;    a second printed circuit board, coupled to the first printed circuit board, wherein the second printed circuit board comprises a heatsink; and    a heat transfer device, wherein the heat transfer device couples between a device mounted on the first printed circuit board and the second printed circuit board, for transferring heat from the device to the heatsink of the second printed circuit board.    
     
     
         2 . The printed circuit board assembly of    claim 1   , wherein the second printed circuit board further comprises an area designed to transfer heat from the device to the heatsink.  
     
     
         3 . The printed circuit board assembly of    claim 1   , further comprising a plate, coupled between the heat transfer device and the second printed circuit board, for providing a larger contact area to the heatsink.  
     
     
         4 . The printed circuit board assembly of    claim 1   , wherein the heatsink is selected from a group comprising a finned heat sink, a heat pipe, and a metallic layer.  
     
     
         5 . The printed circuit board assembly of    claim 1   , wherein the heat transfer device is selected from a group comprising thermal grease, thermal epoxy, and metal.  
     
     
         6 . The printed circuit board assembly of    claim 1   , wherein the second circuit board includes areas where devices are electrically coupled to the second circuit board.  
     
     
         7 . The printed circuit board assembly of    claim 1   , wherein the device is mounted to the first printed circuit board using a ball grid array.  
     
     
         8 . The printed circuit board assembly of    claim 1   , wherein multiple devices are thermally coupled to the second printed circuit board.  
     
     
         9 . The printed circuit board assembly of    claim 1   , wherein the heatsink is situated outboard both the first printed circuit board and the second printed circuit board using a lateral heat spreader block.  
     
     
         10 . The printed circuit board assembly of    claim 1   , further comprising a spacer, wherein the spacer substantially surrounds the device.  
     
     
         11 . The printed circuit board assembly of    claim 10   , wherein the spacer comprises metal spacers for providing electrical conduction between the first printed circuit board and the second printed circuit board.  
     
     
         12 . The printed circuit board assembly of    claim 1   , wherein a spacer is mounted substantially at the periphery of the first printed circuit board.  
     
     
         13 . The printed circuit board assembly of    claim 1   , wherein the second printed circuit board includes plated through holes.  
     
     
         14 . The printed circuit board assembly of    claim 13   , wherein the plated through holes substantially equalize temperatures between a first device and a second device.  
     
     
         15 . The printed circuit board assembly of    claim 1   , wherein the heat transfer device has a variable height to accommodate a first device having a first height and a second device having a second height.  
     
     
         16 . A method for dissipating heat from a device, comprising the steps of: 
 mounting a heat generating device on a first printed circuit board; and    thermally coupling the heat generating device to a heatsink coupled to a second printed circuit board, wherein a thermal path passes through the second printed circuit board.    
     
     
         17 . The method of    claim 16   , wherein the second printed circuit board further comprises an area designed to transfer heat from the device to the heatsink.  
     
     
         18 . The method of    claim 16   , further comprising the step of providing a larger contact area for the heat generating device to the heatsink to dissipate more heat from the heat generating device.  
     
     
         19 . The method of    claim 16   , wherein the heatsink is selected from a group comprising a finned heat sink, a heat pipe, and a metallic layer.  
     
     
         20 . The method of    claim 16   , wherein the thermal coupling between the heat generating device and the second printed circuit board is selected from a group comprising thermal grease, thermal epoxy, and metal.  
     
     
         21 . The method of    claim 16   , wherein the second circuit board includes areas where a device is electrically coupled to the second circuit board.  
     
     
         22 . The method of    claim 16   , wherein the heat generating device is mounted to the first printed circuit board using a ball grid array.  
     
     
         23 . The method of    claim 16   , wherein multiple heat generating devices are thermally coupled to the second printed circuit board.  
     
     
         24 . The method of    claim 16   , wherein the heatsink is situated outboard both the first printed circuit board and the second printed circuit board.  
     
     
         25 . A printed circuit board assembly manufactured by the steps comprising: 
 mounting a heat generating device on a first printed circuit board; and    thermally coupling the heat generating devices to a heatsink coupled to a second printed circuit board; wherein a thermal path passes through the second printed circuit board.    
     
     
         26 . The printed circuit board of    claim 25   , wherein multiple heat generating devices are thermally coupled to the second printed circuit board.