Stackable molded microelectronic packages

1. A microelectronic package comprising:

a substrate having a first surface and a second surface remote from the first surface;

a microelectronic element overlying the first surface;

a conductive post projecting above at least one of the first or second surfaces, the conductive post having a top surface remote from the substrate and one or more edge surfaces extending from the substrate to the top surface of the conductive post;

a conductive bond metal contacting the top and edge surfaces of the conductive post;

conductive elements exposed at the second surface of the substrate, the conductive elements being electrically interconnected with the microelectronic element; and

an encapsulant overlying at least a portion of the microelectronic element and the surface of the substrate above which the conductive post projects, the encapsulant having an opening that partially exposes the conductive bond metal.

2. The microelectronic package as claimed in claim 1 , wherein the conductive bond metal comprises solder.

3. The microelectronic package as claimed in claim 1 , wherein the conductive post has a frusto-conical shape.

4. The microelectronic package as claimed in claim 1 , wherein at least one of the first or second surfaces has a first region and a second region extending from the first region, the microelectronic element overlies the first region, and the conductive post is aligned with the second region and projects to a first height above the second region, the encapsulant contacts the conductive post and has a major surface above the second region at a second height above the second region, the second height being greater than the first height, wherein the opening in the encapsulant is an opening in the major surface.

5. The microelectronic package as claimed in claim 4 , wherein the major surface of the encapsulant is a substantially planar surface, the encapsulant further having a second surface overlying the microelectronic element at a third height above the first surface, the third height being different from the second height.

6. The microelectronic package as claimed in claim 5 , wherein the third height is greater than the second height.

7. The microelectronic package as claimed in claim 1 , wherein the major surface of the encapsulant is a substantially planar surface overlying the first and second regions of the first surface at an at least substantially uniform second height therefrom and overlying the microelectronic element.

8. The microelectronic package as claimed in claim 1 , wherein at least one of the first or second surfaces has a first region and a second region extending from the first region, the microelectronic element overlies the first region, and the conductive post is aligned with the second region and projects to a first height above the second region, wherein the conductive post includes a tip region remote from the microelectronic element and a second region disposed below the tip region and closer to the substrate, the second region and the tip region having respective concave circumferential surfaces, and the conductive post consisting essentially of metal and having a horizontal dimension which is a first function of vertical location in the tip region and which is a second function of vertical location in the second region.

9. The microelectronic package as claimed in claim 1 , wherein the conductive elements include at least one of: conductive posts or masses of conductive bonding material, and a portion of the encapsulant overlies the second surface and further has a plurality of second openings, each second opening partially exposing at least one of the conductive elements, wherein at least some of the conductive elements are electrically insulated from one another and adapted to simultaneously carry different electric potentials.

10. The microelectronic package as claimed in claim 1 , wherein the conductive bond metal comprises solder.

11. The microelectronic package as claimed in claim 1 , wherein the conductive bond metal overlies the conductive post.

12. A microelectronic package comprising:

a substrate having a first surface and a second surface remote from the first surface;

a microelectronic element overlying the first surface;

a solder mass projecting above at least one of the first or second surfaces, the conductive mass having a top surface remote from the substrate;

conductive elements exposed at the second surface of the substrate, the conductive elements being electrically interconnected with the microelectronic element; and

an encapsulant overlying at least a portion of the microelectronic element and the surface of the substrate above which the conductive mass projects, the encapsulant having a tapered opening that partially exposes the top surface of the conductive solder mass.

13. The microelectronic package as claimed in claim 12 , wherein the top surface of the conductive mass is substantially flat.

14. A method of making a microelectronic package comprising:

providing a microelectronic assembly including a substrate, a microelectronic element mounted to the substrate and metal posts having top surfaces remote from the substrate, edge surfaces extending away from the top surfaces towards the substrate and the metal posts having frusto-conical shape, wherein first and second ones of the metal posts are electrically connected by conductive features of the substrate with the microelectronic element for carrying a first signal electric potential on the first metal post and for simultaneously carrying a second electric potential on the second metal post, the second electric potential being different from the first signal electric potential;

then forming an encapsulant layer overlying at least a portion of the substrate and overlying at least a portion of the microelectronic element and covering the top surfaces and the edge surfaces of the metal posts; and

then forming openings in the encapsulant layer, each opening aligned with at least one of the metal posts, each opening permitting an electrical connection to be made with at least one of the metal posts.

15. The method as claimed in claim 14 , wherein the encapsulant layer contacts the metal posts and the forming openings includes forming an opening which partially exposes at least one of the metal posts.

16. The method as claimed in claim 14 , wherein the microelectronic assembly further includes conductive masses joined with respective ones of the metal posts, and each of the openings formed in the encapsulant layer at least partially exposes at least one of the conductive masses.

17. The method as claimed in claim 14 , in which at least first and second microelectronic packages are made, further comprising stacking the second microelectronic package atop the first microelectronic package, the first and second microelectronic packages being electrically interconnected together using the metal posts of at least one of the first and second microelectronic packages.

18. The method as claimed in claim 14 , wherein the step of forming the encapsulant layer includes forming first and second substantially planar surfaces of the encapsulant layer above a surface of the substrate, the first surface overlying at least a portion of the substrate aligned with the microelectronic element and the second surface overlying another portion of the substrate beyond an edge of the microelectronic element, the first and second surfaces having different heights from the surface of the substrate.

19. The method as claimed in claim 14 , wherein the conductive masses are solder masses contacting the top surfaces and edge surfaces of the metal posts.