Thin multi-chip flex module

Abstract

A multichip module comprises a multilayer substrate circuit having conductive patterns on its surface(s) to which microelectronic device(s) are attached. A part of the substrate is flexible and bifurcated. Two rigid members are attached lengthwise, one on either side of the substrate, and the free ends of the bifurcation are reflexed respectively about these members and bonded to them. Electrodes are located on the bifurcations so that they will be exposed outwardly and/or downwardly after reflexing. The module may further be provided with protective heat spreading covers. The electrodes and rigid members may be configured to engage a mating socket or they may be solderable to a printed circuit board.

1. A multichip module comprising:
 a multilayer dielectric substrate comprising two plies, each of said two plies having conductive patterns on both surfaces thereof; 
 a plurality of microelectronic devices attached to said substrate and operably coupled to said conductive patterns on said two plies; 
 a bonding layer joining said two plies over a first portion of their respective areas while a second portion of their respective areas is unbonded so that a bifurcated sheet is formed; 
 two generally elongated rigid dielectric members, one on each side of said multilayer dielectric substrate, configured so that the free ends of said bifurcated sheet may be reflexed respectively about said two rigid members and bonded thereto; and, 
 electrodes disposed on said bifurcated sheet so that said electrodes are exposed after said reflexing. 
 
     
     
       2. The multichip module of  claim 1  wherein said exposed electrodes are facing outwardly on respective sides of said module. 
     
     
       3. The multichip module of  claim 1  wherein said exposed electrodes are facing downwardly on the bottom edge of said module. 
     
     
       4. The multichip module of  claim 1  wherein said microelectronic devices are selected from the group consisting of: memory circuits, logic circuits, buffer devices, interface devices, optoelectronic devices, liquid crystal displays, passive RF devices, active RF devices, and microprocessors. 
     
     
       5. The multichip module of  claim 4  wherein said module comprises at least one RF device and said module further comprises an antenna operably connected to said RF device. 
     
     
       6. The multichip module of  claim 1  wherein said multilayer dielectric substrate comprises more than two plies, and each of said plies further contains conductive vias. 
     
     
       7. The multichip module of  claim 1  wherein said elongated rigid members are configured to engage a mating socket. 
     
     
       8. The multichip module of  claim 1  further comprising a protective cover. 
     
     
       9. The multichip module of  claim 8  wherein said protective cover comprises a heat spreading surface. 
     
     
       10. The multichip module of  claim 1  wherein said exposed electrodes are configured to be solderable to a printed circuit board. 
     
     
       11. The multichip module of  claim 1  wherein said elongated rigid members are attached to said multilayer substrate by adhesive bonding. 
     
     
       12. The multichip module of  claim 1  wherein said microelectronic devices are arranged substantially symmetrically on both sides of said multilayer substrate. 
     
     
       13. The multichip module of  claim 1  wherein said microelectronic devices comprise a cellular telephone transceiver circuit.