Increased Stand-Off Height Integrated Circuit Assemblies, Systems, and Methods

Abstract

Disclosed are integrated circuit assemblies with increased stand-off height and methods and systems for their manufacture. Methods of the invention provide for assembling a semiconductor device by aligning a die with a substrate and interposing solder between corresponding substrate and die bond pads. A lifting force is applied to the die during heating of the solder to a liquescent state, thereby increasing the stand-off height of the die above the substrate. The lifting force is maintained during cooling of the solder to a solid state, thereby forming increased stand-off height solder connections.

1 . An integrated circuit assembly comprising:
 a substrate having a plurality of solder pads;   a semiconductor die adjacent to the substrate and having a plurality of corresponding bond pads aligned with solder pads of the substrate;   an aperture through the substrate and covered by the die adapted to pass a push pin;   a plurality of solder bonds between corresponding substrate solder pads and die bond pads, the vertical dimension of the solder bonds is greater than the horizontal dimension of the solder bonds.   
   
   
       2 . An integrated circuit assembly according to  claim 1  wherein the shaped of the solder bonds are such that:
   1.2* Dd>Ds> 0.7* Dd      
     where,
 Dd is the widest dimension of the solder bond, and 
 Ds is the narrowest dimension of the solder bond. 
 
   
   
       3 . An integrated circuit assembly according to  claim 1  further comprising multiple apertures covered by the die in the substrate filled with encapsulant. 
   
   
       4 . An integrated circuit assembly according to  claim 1  further comprising multiple apertures in the substrate filled with underfill material. 
   
   
       5 . A system for the manufacture of integrated circuit assembly comprising:
 means for aligning a surface mountable die with a substrate;   means for interposing solder bumps between the die and substrate for the formation of solder bonds;   means for heating the solder bumps to liquescence;   means for applying a separating force to increase the stand-off height between the die and the substrate during solder bump liquescence; and   means for permitting the solder to solidify during the application of the separating force, thereby forming solder joints between the die and substrate.   
   
   
       6 . A system for the manufacture of an increased stand-off height integrated circuit assembly according to  claim 5  wherein the shape of the solder joints are such that:
   1.2 *Dd>Ds> 0.7* Dd,      
     where,
 Dd is the widest dimension of the solder joint, and 
 Ds is the narrowest dimension of the solder joint.