Gap control between interposer and substrate in electronic assemblies

Abstract

Electronic assemblies and methods for forming assemblies are described. One embodiment includes a method of forming an electronic assembly, including forming a plurality of first solder bumps on one of a substrate and an interposer. The substrate and interposer are positioned so that the first solder bumps are located between the substrate and the interposer. A gap control structure is positioned between the substrate and the interposer. A first reflow operation that reflows and then solidifies the first solder bumps is performed. The first reflow operation couples the interposer to the substrate. A plurality of second solder bumps are formed on one of the interposer and a die. The interposer and die are positioned so that the second solder bumps are located between the interposer and the die. A second reflow operation that reflows and then solidifies the second solder bumps is performed. The second reflow operation couples the die to the interposer. The second reflow operation also reflows the first solder bumps, and the gap control structure between the substrate and the interposer inhibits a change in a gap between the substrate and the interposer during the second reflow operation. Other embodiments are described and claimed.

1 - 14 . (canceled)  
   
   
       15 . An electronic assembly comprising: 
 a substrate;    an interposer coupled to the substrate through first solder bumps,    a gap control structure positioned between the substrate and the interposer, the gap control structure spaced apart from the first solder bumps, the gap control structure formed from a material having a higher melting point than the solder bumps;    wherein the interposer is separated from the substrate by the first solder bumps and by gap control structures; and    a die coupled to the interposer through second solder bumps, the die separated from the substrate by the second solder bumps.    
   
   
       16 . An electronic assembly as in  claim 15 , wherein the gap control structure comprises a plurality of spaced apart bodies positioned between the substrate and the interposer.  
   
   
       17 . An electronic assembly as in  claim 16 , wherein the gap control structure is formed from a polymer material that remains rigid at a temperature that reflows the first solder bumps.  
   
   
       18 . An electronic assembly as in  claim 15 , further comprising an underfill polymer material positioned between the substrate and the interposer and between the interposer and the die.