Package and method for attaching an integrated heat spreader

Abstract

In some embodiments, an integrated circuit package includes a substrate and a heat spreader coupled to the substrate by fasteners. Thermal interface material thermally couples the die to the heat spreader. The heat spreader is provided over the die and is attached to the substrate with fasteners rather than a sealant-adhesive. Some examples of suitable fasteners may include rivets, barbed connectors, and gripping clips.

What is claimed is:  
     
         1 . A package comprising: 
 a substrate;    a heat spreader coupled to the substrate with a plurality of fasteners; and    a die mounted on the substrate and thermally coupled to the heat spreader with an interface material.    
     
     
         2 . The package of  claim 1  wherein the heat spreader has recesses on a surface opposite the substrate to receive heads of the fasteners.  
     
     
         3 . The package of  claim 2  wherein the fasteners are rivets and wherein the substrate has holes therethrough aligned with holes in a perimeter region of the heat spreader, the rivets to extend through the aligned holes in the substrate and the perimeter region.  
     
     
         4 . The package of  claim 1  wherein the die is coupled to a central region of the heat spreader with thermal interface material, wherein the fasteners couple a perimeter region of the heat spreader region to the substrate.  
     
     
         5 . The package of  claim 4  wherein the perimeter region has a thickness greater than the central region by approximately a height of the die plus a thickness of the thermal interface material, the fasteners provided through holes in the perimeter region.  
     
     
         6 . The package of  claim 4  wherein the perimeter region has a thickness less than or approximately equal to a thickness of the central region, and wherein the substrate has standoffs to align with portions of the perimeter region, the standoffs having a height approximately at least as great as a height of the die plus a thickness of the thermal interface material, the fasteners to be received through holes in the perimeter region aligned with holes in the standoffs.  
     
     
         7 . The package of  claim 4  further comprising standoffs to align with portions of the perimeter region, the standoffs having a height approximately at least as great as a height of the die plus a thickness of the thermal interface material, the standoffs adhered to the substrate with an adhesive.  
     
     
         8 . The package of  claim 4  wherein the substrate includes standoffs to align with portions of the perimeter region, the standoffs having a height approximately at least as great as a height of the die plus a thickness of the thermal interface material, the standoffs being part of the substrate.  
     
     
         9 . The package of  claim 6  wherein the standoffs provide at least a partial cavity between a surface of the substrate to receive an end of the fasteners, the fasteners extending through the holes in the heat spreader into the at least partial cavities of the standoffs, the fasteners having a length not exceeding a height approximately at least as great as a height of the die plus a thickness of the thermal interface material plus a thickness of the heat spreader in the perimeter region so as not to extend through the surface of the substrate.  
     
     
         10 . The package of  claim 4  wherein the heat spreader has a substantially uniform thickness throughout the central region and the perimeter region, 
 and wherein the package further comprises one or more spacers between the substrate and heat spreader in the perimeter region, the one or more spacers having a height approximately equal to a height of the die and a thickness of the thermal interface material, the fasteners to be received through holes in the perimeter region aligned with holes in the spacers and holes in the substrate.  
 
     
     
         11 . The package of  claim 6  wherein the fasteners comprise push-broach rivets, the standoffs to retain a head of the rivets.  
     
     
         12 . The package of  claim 6  wherein the fasteners comprise pull broach rivets.  
     
     
         13 . The package of  claim 6  wherein the fasteners comprise barbed fasteners, the barbed fasteners to be received by either retaining rings or blind-cage retaining elements coupled to the substrate.  
     
     
         14 . The package of  claim 13  wherein the barbed fasteners allow the heat spreader to be snapped into position over the die.  
     
     
         15 . The package of  claim 6  wherein the fasteners comprise external gripping clips, the gripping clips being soldered to a surface of the substrate.  
     
     
         16 . The package of  claim 6  wherein the fasteners comprise external gripping clips, the gripping clips extending through the substrate.  
     
     
         17 . The package of  claim 1  wherein the fasteners comprise threaded fasteners.  
     
     
         18 . The package of  claim 1  wherein the substrate has one of either an organic core, or a metallic core, or is a ceramic substrate.  
     
     
         19 . A method comprising: 
 positioning a heat spreader over a die region of a substrate;    aligning holes in a perimeter region of the heat spreader with holes in the substrate; and    fastening the heat spreader to the substrate with fasteners through the aligned holes.    
     
     
         20 . The method of  claim 19  wherein fastening comprises riveting the heat spreader to the substrate with rivets.  
     
     
         21 . The method of  claim 19  wherein the fasteners comprise barbed connectors, and wherein the substrate includes standoffs, and wherein fastening comprises pushing the barbed connectors through the aligned holes into the standoffs.  
     
     
         22 . The method of  claim 19  wherein the substrate includes standoffs and wherein the barbed connectors are provided in the aligned holes of the heat spreader, and wherein fastening comprises snapping the barbed connectors into retaining elements in the standoffs.  
     
     
         23 . The method of  claim 19  further comprising: 
 adhering the fasteners to the substrate, the fasteners comprising gripping pins; and  
 sliding the pins through the aligned holes of the heat spreader,  
 wherein fastening comprises sliding a clip over ends of the pins to hold the heat spreader in position over the die.  
 
     
     
         24 . The method of  claim 19  wherein a thermal interface material thermally couples the die to the heat spreader, and wherein the method further comprises after fastening, curing the interface material at an elevated temperature.  
     
     
         25 . A system comprising: 
 an organic circuit board; and    one or more packages mounted on the circuit board, at least one of the one or more packages comprising a substrate and a heat spreader coupled to the substrate with a plurality of fasteners.    
     
     
         26 . The system of  claim 25  wherein the heat spreader has recesses on a surface opposite the substrate to receive heads of the fasteners, and wherein the fasteners are rivets and wherein the substrate has holes therethrough aligned with holes in a perimeter region of the heat spreader, the rivets to extend through the aligned holes in the substrate and the perimeter region.  
     
     
         27 . The system of  claim 25  wherein at least one of the packages further comprises a die coupled to a central region of the heat spreader with thermal interface material, the die being mounted on the substrate, wherein the fasteners couple a perimeter region of the heat spreader region to the substrate, 
 wherein the perimeter region has a thickness less than or approximately equal to a thickness of the central region, and wherein the substrate has standoffs to align with portions of the perimeter region, the standoffs having a height approximately at least as great as a height of the die plus a thickness of the thermal interface material, the fasteners to be received through holes in the perimeter region aligned with holes in the standoffs