Stacked microelectronic assemblies with central contacts

Abstract

A stacked microelectronic assembly includes a dielectric element and a first and second microelectronic element stacked one on top of the other with the first microelectronic element underlying at least a portion of the second microelectronic element. The first microelectronic element and the second microelectronic element have front surfaces on which exposed on a central region of the front surface are contacts. A spacer layer may be provided under a portion of the second microelectronic element opposite a portion of the second microelectronic element overlying the first microelectronic element. Additionally, a third microelectronic element may be substituted in for the spacer layer so that the first microelectronic element and the third microelectronic element are underlying opposing sides of the second microelectronic element.

The invention claimed is: 
     
       1. A microelectronic assembly comprising:
 a dielectric element having an upwardly-facing first surface and a downwardly-facing second surface and having, terminals exposed at said second surface, a first aperture, and a second aperture; 
 a first microelectronic element overlying said dielectric element, the first microelectronic element having an upwardly-facing rear surface and a downwardly-facing front surface and having contacts exposed at said front surface; and 
 a second microelectronic element having an upwardly-facing rear surface and a downwardly-facing front surface, having contacts exposed at said front surface, said front surface of said second microelectronic element including a central region and a first and second end region regions on opposite sides of said central region, said contacts of said second microelectronic element being disposed in said central region and facing downwardly toward said dielectric element, said first side end region overlying said first microelectronic element, said central region and said second side end region projecting outwardly from said first microelectronic element, said first aperture underlying said contacts of said first microelectronic element, said second aperture underlying said contacts of said second microelectronic element, wherein said first and second microelectronic elements are electrically connected with said terminals. 
 
     
     
       2. The microelectronic assembly of  claim 1 , wherein said first microelectronic element has a central region and a first and second side region, said contacts of said first microelectronic element being disposed within said central region of said first microelectronic element. 
     
     
       3. The microelectronic assembly of  claim 1 , wherein said dielectric element includes at least one aperture, said aperture substantially underlying said contacts of said front surface of said first microelectronic element. 
     
     
       4. The microelectronic assembly of  claim 1 , wherein said dielectric element includes at least one aperture, said aperture substantially underlying said contacts of said front surface of said second microelectronic element. 
     
     
       5. The microelectronic assembly of  claim 1 , further comprising a spacer layer, wherein said second side end region of said second microelectronic element overlies said spacer layer. 
     
     
       6. The microelectronic assembly of  claim 1 , further comprising a third microelectronic element, wherein said second side end region of said second microelectronic element overlies said third microelectronic element. 
     
     
       7. The microelectronic assembly of  claim 6 , further comprising an adhesive layer, wherein said adhesive layer connects said first microelectronic element and said third microelectronic element to said second microelectronic element. 
     
     
       8. The microelectronic assembly of  claim 2 , further comprising a third microelectronic element, wherein said second end region of said second microelectronic element overlies said third microelectronic element. 
     
     
       9. The microelectronic assembly of  claim 8 , wherein said third microelectronic element is substantially similar to said first microelectronic element. 
     
     
       10. The microelectronic assembly of  claim 9 , wherein said dielectric element underlies at least a portion of said third microelectronic element. 
     
     
       11. The microelectronic assembly of  claim 1 , further comprising a first encapsulant material, wherein said first encapsulant material is disposed in contact with said first microelectronic element and said second microelectronic element. 
     
     
       12. The microelectronic assembly of  claim 6 , further comprising a first encapsulant material, wherein said first encapsulant material is disposed in contact with said first microelectronic element, said second microelectronic element and said third microelectronic element. 
     
     
       13. The microelectronic assembly of  claim 1 , further comprising an adhesive layer, wherein said adhesive layer connects said first microelectronic element to said second microelectronic element. 
     
     
       14. The microelectronic assembly of  claim 1 , further comprising wire leads, wherein said first and second microelectronic elements are electrically connected with said terminals via said wire leads. 
     
     
       15. The microelectronic assembly of  claim 1 , further comprising traces on said dielectric element connected to said terminals and leads integral with said traces, wherein said first and second microelectronic elements are electrically connected with said terminals via said leads. 
     
     
       16. A microelectronic assembly comprising:
 a dielectric element having an upwardly-facing first surface and a downwardly-facing second surface and having terminals exposed at said second surface;   a first microelectronic element having an upwardly-facing rear surface and a downwardly-facing front surface and having contacts exposed at said front surface; and   a second microelectronic element having an upwardly-facing rear surface and a downwardly-facing front surface, having contacts exposed at said front surface, said front surface of said second microelectronic element including a central region and a first and second region on opposite sides of said central region, said contacts of said second microelectronic element being disposed in said central region, further wherein said first side region overlies said first microelectronic element, said central region and said second side region projecting outwardly from said first microelectronic element wherein said first and second microelectronic elements are electrically connected with said terminals.   
     
     
       17. A microelectronic assembly comprising:
 a first microelectronic element having an upwardly-facing rear surface and a downwardly-facing front surface and having contacts exposed at said front surface; and   a second microelectronic element having an upwardly-facing rear surface and a downwardly-facing front surface, having contacts exposed at said front surface, said front surface of said second microelectronic element including a central region and a first and second end region on opposite sides of said central region, said contacts of said second microelectronic element being disposed in said central region, said first side region overlying said first microelectronic element, said central region and said second side region projecting outwardly from said first microelectronic element.   
     
     
       18. The microelectronic assembly of  claim 17 , wherein said first microelectronic element has a central region and a first and second side region, said contacts of said first microelectronic element being disposed in said central region of said first microelectronic element. 
     
     
       19. The microelectronic assembly of  claim 17 , further comprising a spacer layer, wherein said second side region of said second microelectronic element is overlying said spacer layer. 
     
     
       20. The microelectronic assembly of  claim 17 , further comprising a third microelectronic element, wherein said second side region of said second microelectronic element is overlying said third microelectronic element. 
     
     
       21. The microelectronic assembly of  claim 18 , further comprising a third microelectronic element, wherein said second region of said second microelectronic element overlies said third microelectronic element. 
     
     
       22. The microelectronic assembly of  claim 20 , wherein said third microelectronic element is substantially similar to said first microelectronic element. 
     
     
       23. The microelectronic assembly of  claim 17 , further comprising a first encapsulant material, wherein said first encapsulant material is disposed in contact with said first microelectronic element and said second microelectronic element. 
     
     
       24. The microelectronic assembly of  claim 17 , further including an adhesive layer, wherein said adhesive layer connects said first microelectronic element to said second microelectronic element. 
     
     
       25. The microelectronic assembly of  claim 20 , further comprising an adhesive layer, wherein said adhesive layer connects said first microelectronic element and said third microelectronic element to said second microelectronic element. 
     
     
       26. The microelectronic assembly of  claim 17 , further comprising a circuit board and masses of conductive material, said masses of conductive material connecting said contacts of said first microelectronic element and said contacts of said second microelectronic element to said circuit board. 
     
     
       27. The microelectronic element assembly of  claim 26 , wherein said conductive material includes solder. 
     
     
       28. The microelectronic assembly of claim 1, wherein said dielectric element includes a first intermediate portion disposed between said first and second apertures, and said terminals include intermediate terminals disposed on said first intermediate portion. 
     
     
       29. The microelectronic assembly of claim 28 further comprising a third microelectronic element overlying said dielectric element, wherein said second end region of said second microelectronic element overlies said third microelectronic element. 
     
     
       30. The microelectronic assembly of claim 28 wherein said third microelectronic element has an upwardly-facing rear surface, a downwardly-facing front surface and contacts exposed at the front surface of the third microelectronic element. 
     
     
       31. The microelectronic assembly of claim 30 wherein said dielectric element includes a third aperture underlying said contacts of said third microelectronic element. 
     
     
       32. The microelectronic assembly of claim 31 wherein said dielectric element includes a second intermediate portion disposed between said second and third apertures and said terminals include second intermediate terminals disposed on said second intermediate portion. 
     
     
       33. The microelectronic assembly of claim 1, further comprising leads extending through said apertures, said contacts being connected to said terminals via said leads. 
     
     
       34. The microelectronic assembly of claim 33, wherein said leads include first leads extending through said first aperture to said contacts of said first microelectronic element and second leads extending through said second aperture to said contacts of said second microelectronic element. 
     
     
       35. The microelectronic assembly of claim 33 wherein said dielectric element includes bond pads exposed at said second surface and electrically connected to said terminals, and said leads include wire bonds extending through said apertures from said contacts to said bond pads. 
     
     
       36. The microelectronic assembly of claim 33, wherein said dielectric element includes a first intermediate portion disposed between said first and second apertures and said terminals include first intermediate terminals disposed on said first intermediate portion. 
     
     
       37. The microelectronic assembly of claim 36, wherein said leads include first leads extending through said first aperture to said contacts of said first microelectronic element and second leads extending through said second aperture to said contacts of said second microelectronic element.