Vertically stackable sockets for chip modules

1. A socket system for electronic devices, said socket system comprising:

a first socket mountable on a substrate, said first socket including a first opening therein to receive a first chip module;

a second socket stackable on said first socket, said second socket including a second opening therein to receive a second chip module;

a first set of embedded contacts in said first socket to electrically connect said first chip module to said substrate;

a second set of embedded contacts in said first socket to electrically connect said second socket to said substrate;

a third set of embedded contacts in said second socket to electrically connect said second chip module to said substrate;

wherein said first socket further includes a frame surrounding said first opening and a series of first projections that extend from said frame into said first opening for mating with complementary projections on said first chip module.

2. The socket system of claim 1 wherein said second socket further includes a frame surrounding said second opening and a series of second projections that extend from said frame into said second opening for mating with complementary projections on said second chip module.

3. The socket system of claim 1 wherein said first socket surface mounts on said substrate and wherein said second socket surface mounts on an upper surface of said first socket.

4. The socket system of claim 1 further including one or more retention members to retain said second socket on said first socket.

5. The socket system of claim 1 wherein said first socket further includes a heat sink.

6. The socket system of claim 1 wherein said frames of said first and second sockets are made of a metalized plastic.

7. The socket system of claim 1 further comprising a keying mechanism to prevent incorrect alignment of said first and second sockets.

8. The socket system of claim 2 wherein said first set of contacts are disposed on said first projections and wherein said third set of contacts are disposed on said second set of projections.

9. The socket system of claim 8 wherein said projections in said first and second sockets include side surfaces and wherein said contacts in said first and third sets of contacts are disposed on the side surfaces of said projections.

10. The socket system of claim 9 wherein one or more of said projections include two contacts disposed on opposing side surfaces of the projection.

11. The socket system of claim 3 wherein said second set of contacts is disposed on said upper surface of said first socket.

12. The socket system of 4 wherein said retention members comprise pins that extend into corresponding pin holes in said first and second sockets.

13. The socket system of claim 4 wherein said retention members comprise spring clips on at least one of said sockets.

14. The socket system of claim 1 further comprising a radio frequency shield disposed between said first and second chip modules to isolate said second chip module from radio frequency emissions from said first chip module.

15. The socket system of claim 14 wherein said second socket further includes a metalized bottom forming said radio frequency shield.

16. The socket system of claim 7 wherein said keying mechanism comprises one or more locating pins on at least one of said sockets and one or more corresponding pin holes on the other one of said sockets.