Enhanced die-up ball grid array and method for making the same

Abstract

An electrically and thermally enhanced die-up tape substrate ball grid array (BGA) package and die-up plastic substrate BGA package are described. A substrate that has a first surface and a second surface is provided. The stiffener has a first surface and a second surface. The second stiffener surface is attached to the first substrate surface. An IC die has a first surface and a second surface. The first IC die surface is mounted to the first stiffener surface. A plurality of solder balls is attached to the second substrate surface. In one aspect, a heat spreader is mounted to the second IC die surface. In another aspect, the stiffener is coupled to ground to act as a ground plane. In another aspect, the substrate has a window opening that exposes a portion of the second stiffener surface. The exposed portion of the second stiffener surface is configured to be coupled to a printed circuit board (PCB). In another aspect, a metal ring is attached to the first stiffener surface. In another aspect, wire bond openings in the stiffener are bridged by one or more studs.

1 - 33 . (canceled).  
   
   
       34 . A method of assembling a ball grid array (BGA) package, comprising the steps of: 
 providing a tape substrate that has a first surface and a second surface;    attaching a first surface of a stiffener to the first substrate surface;    mounting an IC die to the second stiffener surface;    mounting a heat spreader to the IC die; and    attaching a plurality of solder balls to the second substrate surface.    
   
   
       35 . The method of  claim 34 , wherein said heat spreader mounting step comprises the step of: 
 causing thermal stress to be reduced at an interface of the IC die and the first stiffener surface during operation of the IC die.    
   
   
       36 . A method of assembling a ball grid array (BGA) package, comprising the steps of: 
 providing a substrate that has a first surface and a second surface;    providing at least one opening in a stiffener from a first surface of the stiffener to the second surface of the stiffener;    attaching the first stiffener surface to the first substrate surface;    mounting an integrated circuit (IC) die to the second stiffener surface, wherein a first surface of the IC die includes a contact pad,    coupling the contact pad to the second stiffener surface;    attaching a plurality of solder balls to the second substrate surface, inside an outer dimensional profile of the IC die; and    coupling the plurality of solder balls through corresponding vias in the substrate to the first stiffener surface.    
   
   
       37 . The method of  claim 36 , wherein the substrate includes a metal layer, wherein the metal layer is coupled to a second potential; 
 wherein the stiffener has at least one opening extending from the first stiffener surface to the second stiffener surface;    wherein the second IC die surface includes a second contact pad, wherein the method further comprises the step of:    coupling the second contact pad to the metal layer through one of the at least one openings in the stiffener and through a corresponding via that extends through the substrate.    
   
   
       38 . The method of  claim 36 , further comprising the step of: coupling the contact pad to a ground potential in the IC die.  
   
   
       39 . The method of  claim 37 , further comprising the step of: 
 coupling the second contact pad to a power potential in the IC die.    
   
   
       40 . A method of assembling a ball grid array (BGA) package, comprising the steps of: 
 providing a substrate that has a first surface and a second surface;    attaching a first surface of a stiffener to the first substrate surface;    exposing a portion of the first stiffener surface through a window opening in the substrate;    mounting an IC die to a second stiffener surface, wherein a surface of the IC die includes at least one contact pad; and    attaching a plurality of solder balls to the second substrate surface;    configuring the exposed portion of the first stiffener surface to be coupled to a printed circuit board (PCB), whereby electrical and thermal performance of the BGA package is improved.    
   
   
       41 . The method of  claim 40 , wherein said configuring step comprises the steps of: 
 coupling a heat spreader to the exposed portion of the first stiffener surface; and    configuring a surface of the heat spreader to be coupled to the PCB.    
   
   
       42 . The method of  claim 41 , wherein said configuring step further comprises the step of: 
 plating the heat spreader surface with solder to allow the heat spreader surface to be surface mounted to soldering pads on the PCB.    
   
   
       43 . The method of  claim 40 , wherein said configuring step comprises the step of: 
 shaping the stiffener to have a centrally-located cavity shaped portion that protrudes through the window opening.    
   
   
       44 . The method of  claim 43 , wherein said configuring step further comprises the step of: 
 plating a surface of the cavity shaped portion with a conductive material to allow the stiffener to be surface mounted to contact pads on the PCB.    
   
   
       45 . The method of  claim 43 , further comprising the steps of: 
 coupling the stiffener to a potential;    coupling each of the at least one contact pads to the second stiffener surface with corresponding wire bonds.    
   
   
       46 . The method of  45 , wherein the stiffener coupling step comprises the steps of: 
 coupling the stiffener to a ground potential; and    allowing the stiffener to serve as a ground plane.    
   
   
       47 . A method of assembling a ball grid array (BGA) package, comprising the steps of: 
 providing a substrate that has a first surface and a second surface;    attaching a first surface of a stiffener to the first substrate surface;    mounting an IC die to the first stiffener surface;    attaching a plurality of solder balls to the second substrate surface; and    attaching a metal ring to the first stiffener surface.    
   
   
       48 . The method of  claim 47 , wherein said metal ring attaching step comprises the step of dissipating heat from the stiffener with the metal ring.  
   
   
       49 . The method of  claim 46 , further comprising the step of: 
 mounting an IC die to the first stiffener surface.    
   
   
       50 . A method of assembling a ball grid array (BGA) package, comprising the steps of: 
 providing a substrate that has a first surface and a second surface;    creating a wire bond opening along each edge of an IC die mount position on a stiffener, wherein each wire bond opening extends through the stiffener;    attaching a first surface of the stiffener to the first substrate surface;    mounting an IC die to the IC die mount position on a second surface of the stiffener;    bridging at least one of the wire bond openings with at least one stud; and    attaching a plurality of solder balls to the second substrate surface.    
   
   
       51 . The method of  claim 50 , wherein the IC die includes a contact pad, wherein the method further comprises the step of: 
 coupling the contact pad to the substrate with a wire bond, wherein the wire bond passes through one of the wire bond openings in the stiffener.    
   
   
       52 . A method of assembling a ball grid array (BGA) package, comprising the steps of: 
 providing a substrate that has a first surface and a second surface;    mounting an IC die to the first substrate surface;    attaching a plurality of solder balls to the second substrate surface;    coupling a first surface of a heat spreader to the second substrate surface; and    configuring a second surface of the heat spreader to be coupled to a printed circuit board (PCB).    
   
   
       53 . The method of  claim 52 , further comprising the step of coupling the first substrate surface to the heat spreader through at least one via that extends through the substrate.  
   
   
       54 . The method of  claim 53 , wherein said mounting step comprises the steps of: 
 exposing a copper plated die-attach pad to the center of the first substrate surface; and    mounting the IC die to the copper plated die-attach pad.    
   
   
       55 . The method of  claim 53 , wherein said step of coupling the first substrate surface to the heat spreader comprises the steps of: 
 exposing a copper plated plane to the center of the second substrate surface; and    coupling the die-attach pad to the copper plated plane with the at least one via.    
   
   
       56 . The method of  claim 52 , wherein said configuring step comprises the step of: 
 plating the second surface of the heat spreader with solder.    
   
   
       57 . (canceled)  
   
   
       58 . The method of  claim 43 , further comprising the step of: 
 patterning at least a portion of the second stiffener surface.    
   
   
       59 . The method of  claim 58 , wherein said patterning step comprises: 
 patterning the second stiffener surface with a surface treatment, wherein the surface treatment enhances said step of mounting the IC die to the second stiffener surface.    
   
   
       60 . The method of  claim 58 , wherein said patterning step comprises: 
 patterning the second stiffener surface with a surface texture, wherein the surface texture enhances said step of mounting the IC die to the second stiffener surface.    
   
   
       61 . The method of  claim 43 , wherein said configuring step further comprises the step of: 
 plating a surface of the cavity shaped portion with at least one of a solder, silver, tin, or gold material to allow the stiffener to be surface mounted to contact pads on the PCB.    
   
   
       62 . The method of  claim 45 , further comprising the step of: 
 plating at least one area of the second stiffener surface, wherein the at least one plated area enhances said step of coupling each of the at least one contact pads to the second stiffener surface with the corresponding wire bonds.    
   
   
       63 . The method of  claim 62 , wherein said plating step includes plating the at least one area with a solder, copper, nickel, tin, gold, or silver material.  
   
   
       64 . The method of  claim 43 , wherein said attaching step comprises arranging the plurality of solder balls in an array on a peripheral area of the second substrate surface to accommodate the centrally-located cavity shaped portion of the stiffener that protrudes through the window opening in the substrate.  
   
   
       65 . The method of  claim 43 , further comprising the steps of: 
 forming at least one opening through the stiffener that is open at the first and second stiffener surfaces; and    coupling the at least one contact pad of the IC die to at least one contact point on the first substrate surface with a corresponding wire bond that extends through the at least one opening through the stiffener.    
   
   
       66 . The method of  claim 43 , further comprising the steps of: 
 forming at least one opening through the stiffener that is open at the first and second stiffener surfaces; and    coupling the at least one contact pad of the IC die to the plurality of solder balls with a corresponding wire bond that extends through the at least one opening through the stiffener to at least one via through the substrate.    
   
   
       67 . The method of  claim 43 , further comprising the step of: 
 encapsulating the second stiffener surface with an encapsulating material.    
   
   
       68 . The method of  claim 44 , wherein the contact pads on the PCB are formed from at least one of a copper, nickel, tin, or gold material.