Underfill film having thermally conductive sheet

Abstract

An underfill film for an electronic device includes a thermally conductive sheet. The electronic device may include a printed circuit board, an electrical component, an underfill, and the thermally conductive sheet. The underfill is situated between the circuit board and the component. The thermally conductive sheet is situated within the underfill, and together with the underfill, constitutes the underfill film. The device may include solder bumps affixing the component to the circuit board, the underfill film having holes within which the solder bumps are aligned. There may be solder bumps on the underside of the circuit board promoting heat dissipation. There may be heat sinks on the circuit board to which the thermally conductive sheet is affixed promoting heat dissipation. The thermally conductive sheet may be affixed to a chassis promoting heat dissipation. The thermally conductive sheet thus promotes heat dissipation from the component to at least the circuit board.

1 . An electronic device comprising: 
 a printed circuit board;    an electrical component;    an underfill situated between the printed circuit board and the electrical component; and,    a thermally conductive sheet situated within the underfill.    
   
   
       2 . The electronic device of  claim 1 , further comprising a plurality of solder bumps affixing the electrical component to the printed circuit board, where the underfill and the thermally conductive sheet have a plurality of holes within which the solder bumps are aligned.  
   
   
       3 . The electronic device of  claim 1 , further comprising a plurality of solder bumps affixing the electrical component to the printed circuit board, where the thermally conductive sheet has a plurality of holes within which the solder bumps are aligned.  
   
   
       4 . The electronic device of  claim 1 , further comprising a plurality of solder bumps on an underside of the printed circuit board to promote heat dissipation from the underside of the printed circuit board.  
   
   
       5 . The electronic device of  claim 1 , further comprising one or more heat sinks situated on the printed circuit board, the thermally conductive sheet affixed to the heat sinks to promote heat dissipation from the electrical component to the heat sinks.  
   
   
       6 . The electronic device of  claim 1 , wherein the thermally conductive sheet is affixed to a chassis for the electronic device to promote heat dissipation from the electrical component to the chassis.  
   
   
       7 . The electronic device of  claim 1 , wherein the thermally conductive sheet promotes heat dissipation from the electrical component to the printed circuit board.  
   
   
       8 . The electronic device of  claim 1 , wherein the underfill has relatively poor thermal conductivity.  
   
   
       9 . The electronic device of  claim 1 , wherein the underfill comprises a resin.  
   
   
       10 . The electronic device of  claim 1 , wherein the thermally conductive sheet comprises at least one of a metal sheet, graphite sheet, and a resin or silicone sheet.  
   
   
       11 . The electronic device of  claim 1 , wherein the underfill has a first coefficient of thermal expansion (CTE), the thermally conductive sheet has a second CTE, and the first CTE and the second CTE are substantially equal to one another.  
   
   
       12 . An underfill film for disposal between an electrical component of an electronic device and a circuit board of the electronic device, where the electrical component is affixed to the circuit board by a plurality of a solder bumps, the underfill film comprising: 
 a material to relax thermal stresses resulting from a difference in coefficients of thermal expansion (CTE's) of the circuit board and the solder bumps and from a difference in CTE's of the electrical component and the solder bumps; and,    a thermally conductive sheet situated within the material.    
   
   
       13 . The underfill film of  claim 12 , wherein the material comprises a resin having relatively poor thermal conductivity.  
   
   
       14 . The underfill film of  claim 12 , wherein the thermally conductive sheet comprises at least one of a metal sheet, graphite sheet, and a resin or silicone sheet.  
   
   
       15 . The underfill film of  claim 12 , wherein a CTE of the thermally conductive sheet is substantially equal to a CTE of the material.  
   
   
       16 . The underfill film of  claim 12 , further comprising a plurality of holes through the material and the thermally conductive sheet within which the solder bumps are aligned.  
   
   
       17 . The underfill film of  claim 12 , further comprising a plurality of holes through the thermally conductive sheet within which the solder bumps are aligned.