Method of fabricating a multi-die semiconductor package assembly

Abstract

An apparatus and method for increasing integrated circuit density comprising an upper die and a lower die, the latter preferably a flip chip, which are connected to a conductor-carrying substrate or a leadframe. The upper die is attached back-to-back to the lower die with a layer of adhesive applied over the back side of the lower die. Bond wires or TAB leads are attached between bond pads on the upper die and corresponding conductive trace or lead ends on the substrate. The upper die may be smaller than the lower die such that a small discrete component such as a resistor, capacitor, or the like can be attached to the adhesive not covered by the upper die. Bond wires can be attached between the upper die and the component, as well as between the component and the substrate. One or more additional die may be stacked on the upper die and electrically connected to the substrate. Furthermore, multiple lower dice can be arranged on the substrate to support upper dice bridged between the lower dice.

1 . A method of fabricating a multi-die assembly, comprising: 
 providing a substrate including conductors;    securing an active face-down base die to the substrate    electrically connecting the base die with a conductor of the substrate;    securing an active face-up stack die to the base die;    electrically connecting the stack die with a conductor of the substrate;    securing another stack die to the assembly;    electrically connecting the other stack die wit a conductor of the substrate;    securing a discrete component to at least one of the stack die, the other stack die, and the base die; and    electrically connecting the discrete component to at least one of the stack die, the other stack die, and the base die.    
     
     
         2 . The method of  claim 1 , further comprising electrically connecting the discrete component to a conductor of the substrate.  
     
     
         3 . The method of  claim 2 , further comprising electrically connecting the discrete component to at least one other of the stack die, the other stack die, and the base die.  
     
     
         4 . The method of  claim 1 , wherein electrically connecting the discrete component to at least one of the stack die, the other stack die, and the base die includes extending a bond wire between the discrete component and at least one of the stack die, the other stack die, and the base die.  
     
     
         5 . The method of  claim 1 , further comprising: 
 securing another discrete component to at least one of the stack die, the other stack die, the base die, and the substrate;    electrically connecting the other discrete component to at least one of the stack die, the other stack die, the base die, and a conductor of the substrate; and    electrically connecting the other discrete component to at least another of the stack die, the other stack die, the base die, and a conductor of the substrate.    
     
     
         6 . The method of  claim 1 , wherein securing the stack die to the base die further includes providing a layer of epoxy adhesive between the stack die and the base die.  
     
     
         7 . The method of  claim 6 , wherein providing a layer of epoxy adhesive includes providing a layer of electrically conductive epoxy adhesive.  
     
     
         8 . The method of  claim 7 , further comprising electrically grounding the base die and the stack die via the layer of electrically conductive epoxy adhesive.  
     
     
         9 . The method of  claim 6 , wherein securing a layer of epoxy adhesive between the stack die and the base die further includes curing the layer of epoxy adhesive.  
     
     
         10 . The method of  claim 1 , wherein securing the other stack die to the assembly includes securing the other stack die to the stack die.  
     
     
         11 . The method of  claim 1 , further comprising attaching a second active face-down base die to the substrate and electrically connecting the second base die with a conductor of the substrate.  
     
     
         12 . The method of  claim 11 , further comprising bridging the stack die between the base die and the second base die.  
     
     
         13 . The method of  claim 12 , further comprising: 
 securing an other discrete component to at least one of the stack die, the base die, the second base die, and the substrate; and    electrically connecting the other discrete component to at least one of the stack die, the base die, the second base die, and a conductor of the substrate.    
     
     
         14 . The method of  claim 13 , further comprising electrically connecting the other discrete component to a different at least one of the stack die, the base die, the second base die, and a conductor of the substrate.  
     
     
         15 . The method of  claim 12 , further comprising attaching an additional stack die to the bridge stack die.  
     
     
         16 . A method of fabricating a semiconductor device, comprising: 
 attaching analogous sides of a first die and second die;    securing a discrete component to at least one of the first die and the second die; and    electrically connecting the discrete component to at least one of the first die and the second die.    
     
     
         17 . The method of  claim 16 , wherein attaching analogous sides of the first die and the second die includes attaching the first die and the second die back-to-back.  
     
     
         18 . The method of  claim 16 , further comprising attaching the first die to a substrate including conductors.  
     
     
         19 . The method of  claim 18 , wherein attaching the first die to the substrate includes attaching an active face of the first die to the substrate.  
     
     
         20 . The method of  claim 18 , further comprising electrically connecting the first die to a conductor of the substrate.  
     
     
         21 . The method of  claim 20 , wherein electrically connecting the first die to a conductor of the substrate includes at least one of refluxing a solder ball, curing a conductive polymer ball, soldering a pin, and soldering a J-lead.  
     
     
         22 . The method of  claim 18 , further comprising electrically connecting the discrete component to a conductor of the substrate.  
     
     
         23 . The method of  claim 18 , further comprising electrically connecting the second die to a conductor of the substrate.  
     
     
         24 . The method of  claim 16 , further comprising electrically connecting the discrete component to both the first die and the second die.  
     
     
         25 . The method of  claim 16 , wherein attaching analogous sides of the first die and the second die includes attaching analogous sides of the first die and the second die such that the first die is laterally offset relative to the second die.  
     
     
         26 . The method of  claim 25 , further comprising attaching an analogous side of a third die to the second die.  
     
     
         27 . The method of  claim 26 , further comprising attaching another discrete component to at least one of the first die, the second die, and the third die and electrically connecting the other discrete component to at least one of the first die, the second die, and the third die.  
     
     
         28 . The method of  claim 27 , further comprising electrically connecting the other discrete component to at least another of the first die, the second die, and the third die not previously electrically connected to the other discrete component.  
     
     
         29 . The method of  claim 16 , further comprising attaching an additional die to the second die.  
     
     
         30 . A method of assembling dice, comprising: 
 mounting a plurality of dice over a substrate, wherein at least two dice of the plurality exhibit different electrical connections to conductors of the substrate; and    mounting a discrete component to one of the plurality of dice, wherein the discrete component is electrically connected to at least one of the plurality of dice.    
     
     
         31 . The method of  claim 30 , further comprising extending a wire bond to electrically connect one die of the at least two dice with a conductor of the substrate.  
     
     
         32 . The method of  claim 30 , wherein mounting the die over the substrate includes forming a flip-chip arrangement with at least one of the at least two dice.  
     
     
         33 . A method of fabricating a semiconductor device, comprising: 
 mounting a plurality of dice over a surface of a support structure, wherein at least one die's contact pads face towards the support surface and at least one other die's pads face away from the support surface; and    mounting a discrete component on at least one of the plurality of dice.    
     
     
         34 . The method of  claim 33 , further comprising electrically connecting the plurality of dice to at least one conductor of the support surface.  
     
     
         35 . The method of  claim 33 , further comprising electrically connecting the discrete component to at least one die of the plurality of dice.  
     
     
         36 . The method of  claim 35 , further comprising electrically connecting the discrete component to a conductor of the support surface.  
     
     
         37 . A method of fabricating a multi-die assembly, comprising: 
 providing a substrate including conductors;    attaching at least one base die to the substrate in electrical communication with a conductor of the substrate;    attaching at least one other base die to the substrate in electrical communication with a conductor of the substrate;    attaching at least one stack die back-to-back with the at least one base die and the at least one other base die such that the at least one stack die bridges the at least one base die and the at least one other base die;    electrically connecting the at least one stack die to a conductor of the substrate;    securing at least one discrete component to at least one of the at least one stack die, the at least one base die, the at least one other base die, and the substrate; and    electrically connecting the at least one discrete component and at least one of the at least one stack die, the at least one base die, the at least one other base die, and a conductor of the substrate.    
     
     
         38 . A method of fabricating a dice stack, comprising: 
 providing a substrate including conductors;    attaching two base dice to the substrate, each being in electrical communication with at least one conductor of the substrate;    bridging the two base dice with a stack die such that similar sides of the stack die and the two base dice are attached;    electrically connecting the stack die to a conductor of the substrate;    securing a discrete component to at least one of the stack die, at least one of two base dice, and the substrate; and    electrically connecting the discrete component and at least one of the stack die, at least one of the two base dice, and a conductor of the substrate.    
     
     
         39 . The method of  claim 38 , wherein attaching two base dice to the substrate further includes attaching an active face of at least one of the two base dice to the substrate.  
     
     
         40 . A method of fabricating a multi-die assembly, comprising: 
 providing a substrate including conductors;    securing a base die to the substrate    electrically connecting the base die with a conductor of the substrate;    securing a stack die to the based die with a layer of electrically conductive epoxy adhesive;    providing a direct electrical path between the stack die and a conductor of the substrate; and    electrically grounding the at least one base die via the layer of electrically conductive epoxy adhesive and the at least one stack die.