Stackable microelectronic package structures

1. A microelectronic assembly, comprising:

a first microelectronic package, including:

a substrate having first and second opposed surfaces and substrate contacts thereon;

first and second microelectronic elements each having element contacts electrically connected with the substrate contacts, the first and second microelectronic elements being spaced apart from one another on the first surface so as to provide an interconnect area of the first surface between the first and second microelectronic elements;

a plurality of package terminals at the second surface electrically interconnected with the substrate contacts for connecting the first microelectronic package with a component external to the first microelectronic package; and

a plurality of stack terminals exposed at the first surface in the interconnect area for connecting the first microelectronic package with a component overlying the first surface of the substrate of the first microelectronic package; and

a second microelectronic package overlying the first microelectronic package and having terminals joined to the stack terminals of the first microelectronic package, the second microelectronic package including a substrate having first and second spaced apart surfaces and third and fourth microelectronic elements mounted on the second surface thereof, the third and fourth microelectronic elements being spaced apart on the substrate of the second microelectronic package to define an interconnect area therein, and the terminals being exposed at the second surface of the substrate of the second microelectronic package within the interconnect area of the second microelectronic package, the substrate of the second microelectronic package further including at least one window extending therethrough between the first and second surfaces thereof, and wherein the terminals of the second microelectronic package are electrically connected to the stack terminals of the first microelectronic package.

2. The microelectronic assembly of claim 1 , wherein wire bonds extend through the window between element contacts of the third microelectronic element and contact pads disposed at the substrate of the second microelectronic package, the contact pads being electrically connected to the package terminals of the first and second microelectronic packages.

3. The microelectronic assembly of claim 2 , wherein the substrate of the first microelectronic package further includes a window, and wire bonds extend through the window of the first microelectronic package between element contacts of the first microelectronic element and contact pads disposed at the substrate of the first microelectronic package.

4. The microelectronic assembly of claim 1 , wherein a plurality of interconnect elements extend within the interconnect area of the first microelectronic package and in a vertical direction parallel to adjacent edge surfaces of the first and second microelectronic elements, the plurality of interconnect elements electrically connecting the package terminals of the first microelectronic package with the terminals of the second microelectronic package.

5. The microelectronic assembly of claim 4 , wherein the terminals of the second microelectronic package further comprise package and stack terminals, wherein a plurality of interconnect elements extend within the interconnect area of the second microelectronic package and in a vertical direction parallel to adjacent edge surfaces of the third and fourth microelectronic elements, the plurality of interconnect elements of the second microelectronic package configured to electrically connect the first microelectronic package and stack terminals of the second microelectronic package with the package terminals of a third package.

6. The microelectronic assembly of claim 4 , further comprising an adhesive layer joining the second microelectronic package to the first microelectronic package; and a conductive bonding material disposed within the adhesive layer to conductively join the plurality of interconnect elements of the first microelectronic package with the package terminals of the second microelectronic package.

7. The microelectronic assembly of claim 4 , wherein the plurality of interconnect elements includes at least one of pins, posts, masses of bond metal, and masses of conductive material.

8. The microelectronic assembly of claim 4 , further comprising an adhesive layer joining the second microelectronic package to the first microelectronic package, wherein the plurality of interconnect elements extends through the adhesive layer and electrically interconnects the stack terminals of the first microelectronic package with the package terminals of the second microelectronic package.

9. The microelectronic assembly of claim 8 , wherein the plurality of interconnects of the first microelectronic package directly contact the stack terminals of the first microelectronic package with the terminals of the second microelectronic package.

10. The microelectronic assembly of claim 1 , wherein the interconnect area of the first microelectronic package and at least portions of the first and second microelectronic elements are encapsulated.

11. The microelectronic assembly of claim 10 , wherein the interconnect area of the second microelectronic package and at least portions of the third and fourth microelectronic elements are encapsulated.

12. The microelectronic assembly of claim 1 , wherein wire bonds electrically connect terminals of the second microelectronic package with the stack terminals of the first microelectronic package.

13. The microelectronic assembly of claim 3 , wherein the window of the substrate of the second microelectronic package is a central window aligned with the interconnect area of the second microelectronic package and positioned between the third and fourth microelectronic elements, and wherein wire bonds extend through the window to electrically connect the first and second microelectronic packages.

14. The microelectronic assembly of claim 1 , wherein the substrate of the first microelectronic package defines a first peripheral area surrounding at least one of the first and second microelectronic elements, additional stack terminals being located in the first peripheral area, wherein the substrate of the second microelectronic package defines a second peripheral area surrounding at least one of the third and fourth microelectronic elements and a peripheral edge bounding the second peripheral area, additional terminals being located in the second peripheral area thereof, and wherein at least some of the additional stack terminals of the first microelectronic package are joined with at least some of the additional terminals of the second microelectronic package by wire bonds that extend past the peripheral edge of the substrate of the second microelectronic package.

15. The microelectronic assembly of claim 1 , further including a circuit panel with circuit contacts exposed at a surface thereof, wherein the package terminals of the first microelectronic package are electrically connected with the circuit contacts.

16. The microelectronic assembly of claim 1 , wherein the terminals of the second microelectronic package are at least one of package terminals or stack terminals.

17. The microelectronic assembly of claim 1 , wherein the package terminals and the stack terminals overlie each other in respective electrically connected pairs.

18. The microelectronic assembly of claim 1 , wherein the package terminals and the stack terminals of the first and second microelectronic packages are opposite ends of conductive vias through the respective substrates of the first and second microelectronic packages.