Microelectronic packaging and methods for thermally protecting package interconnects and components

Abstract

Apparatus and methods are provided wherein the reflowable electrically conductive interconnect material coupling the interconnects and/or land-side components of a microelectronic package is protected from elevated temperatures, such as those associated with reflow processes and environments which exceed the melting temperature of the interconnect material. One embodiment of the method provides covering the interconnect material about the interconnects and/or land-side components with heat-resistant curable material which protects the interconnect material from the elevated temperature and provides structural support to the interconnects and/or land-side components at the elevated temperature. One embodiment of the apparatus provides a substrate comprising interconnects and/or land-side components coupled to a carrier substrate with reflowable electrically conductive interconnect material, and a layer of heat-resistant curable material covering the interconnect material and forming fillets about the interconnects and/or land-side components.

1 . A method, comprising: 
 providing a carrier substrate having a land side and a die side opposite the land side, the land side including a pin that is coupled to the land side with reflowable electrically conductive interconnect material;    covering a layer of curable material on the interconnect material about the pin; and    curing the curable material into a hardened state to contain the pin from de-coupling with an interconnect land pad on the surface of the land side of the carrier substrate at temperatures exceeding the melting temperature of the interconnect material.    
   
   
       2 . The method of  claim 1 , further comprising: 
 coupling a land-side component to the land side of the carrier substrate with another collection of reflowable electrically conductive interconnect material,    covering the other collection of interconnect-material about the land-side component with another layer of curable material; and    curing the curable material covering the other collection of interconnect material about the land-side component into a hardened state to contain the land-side component from de-coupling from a component land pad on the land side of the carrier substrate at temperatures exceeding the melting temperature of the other collection of interconnect material.    
   
   
       3 . The method  claim 1 , further comprising coupling a microelectronic die to the die side of the carrier substrate.  
   
   
       4 . The method  claim 3 , further comprising-coupling a heat dissipation device to the die.  
   
   
       5 . The method of  claim 1 , wherein said providing comprises providing a carrier substrate including a pin selected from the group consisting of a flat-headed pin and a through-hole pin.  
   
   
       6 . The method of  claim 1 , wherein said providing comprises providing a carrier substrate including a pin of a flip chip-pin grid array package.  
   
   
       7 . The method of  claim 1 , wherein said providing comprises coupling the pin to the land side with a reflowable electrically conductive interconnect material selected from the group consisting of lead-free solder and solder comprising lead.  
   
   
       8 . The method  claim 1 , wherein said covering comprises covering a layer of curable material that is at least 0.010 inches thick on the interconnect material about the pin.  
   
   
       9 . The method of  claim 1 , wherein said covering comprises covering the interconnect material about the pin with a curable material having a viscosity that allows the curable material to form a fillet about the pin.  
   
   
       10 . The method of  claim 1 , further comprising: 
 coupling a land-side component to the land side of the carrier substrate with another collection of reflowable electrically conductive interconnect material;    coupling a microelectronic die to the die side of the carrier substrate;    coupling a heat dissipation device to the die; and    covering the other collection of reflowable electrically conductive interconnect material about the land-side component with another-layer of curable material and curing the curable material into a hardened state to contain the land-side component from de-coupling from a component land pad on the land side of the carrier substrate at temperatures exceeding the melting temperature of the interconnect material, and the layer of curable material having a predetermined viscosity that allows the curable material to form fillets about the pin and land-side component.    
   
   
       11 . A method, comprising: 
 providing a substrate with a land side and a die side opposite the land side, the land side having a plurality of interconnect land pad arrays, each of the plurality of interconnect land-pad arrays having a plurality of interconnect land pads;    coupling one or more pins to one or more of the plurality of interconnect land pads with reflowable electrically conductive interconnect material;    covering a layer of curable material on the reflowable electrically conductive interconnect material about the one or more pins; and    curing the curable material into a harden state to contain the one or more pins from decoupling from the one or more of the plurality of interconnect land pads at temperatures exceeding the melting temperature of the interconnect material.    
   
   
       12 . The method of  claim 11 , wherein one or more of the plurality of interconnect land pad arrays further includes one or more component land-pads, and the method further comprises: 
 coupling one or more land-side components to the one or more component land-pads with another collection of reflowable electrically conductive interconnect material;    covering the other collection of interconnect material about the land-side components with another layer of curable material; and    curing the curable material and hardening the curable material to contain the one or more land-side components from de-coupling with the one or more of the component land-pads at temperatures exceeding the melting temperature of the other collection of interconnect material.    
   
   
       13 . The method of  claim 12 , further comprising forming one or more die land-pad arrays on the die side of the substrate, the one or more die land-pad arrays corresponding to one or more of the plurality of interconnect land pad arrays, one die land-pad array being opposite to one interconnect land pad array, each die land-pad array having a plurality of die land pads.  
   
   
       14 . The method of  claim 13 , further comprising coupling a microelectronic die having an array of bond pads that are located on the microelectronic die in a complementary manner to one die land-pad array, wherein the coupling includes coupling the bond pads to the die land pads with still another collection of reflowable electrically conductive interconnect material.  
   
   
       15 . A method for assembling a microelectronic package, comprising: 
 providing a carrier substrate including an array of interconnects coupled to a land side with reflowable electrically conductive interconnect material;    applying a layer of curable material on the interconnect material about the interconnects, wherein the curable material, once cured to a solid state, contains the interconnects from de-coupling from the land side at temperatures exceeding the melting temperature of the interconnect material; and    curing the layer of curable material.    
   
   
       16 . The method of  claim 15 , wherein applying a layer of curable material on the interconnect material comprises applying a layer of material having reflowable electrically conductive particulate interconnect material commixed with curable material to the interconnect material.  
   
   
       17 . The method of  claim 15 , further comprising coupling one or more land-side components to the land side with another collection of reflowable electrically conductive interconnect material; and 
 applying a layer of curable material about the other collection of interconnect material of the one or more land-side components, and wherein the curable material about the one or more land-side components, once cured to a solid state, contain the land-side components from de-coupling at temperatures exceeding the melting temperature of the other collection of interconnect material.    
   
   
       18 . The method of  claim 17 , wherein the array of interconnects are oriented around an outer portion of the land side defining a central portion having no interconnect land-pads, the one or more land-side components being coupled within the central portion, and wherein applying a layer of curable material on the interconnect material about the interconnects comprises depositing the curable material onto the land side between the array of interconnects and the one or more land-side components, wherein the curable material migrates to and covers the interconnect material and form fillets about the interconnects and the one or more land-side components via capillary action.  
   
   
       19 . The method of  claim 15 , wherein applying a layer of curable material comprises dispensing the curable material in a liquid or semi-liquid form, flowing the curable material about the interconnects to cover the interconnect material, and forming fillets about the interconnects via capillary action.  
   
   
       20 . The method of  claim 19 , further comprising heating the carrier substrate prior to dispensing the curable material.