Semiconductor module with serial bus connection to multiple dies

Abstract

A semiconductor module is provided which includes a beat heat spreader, at least two semiconductors thermally coupled to the heat spreader, and a plurality of electrically conductive leads electrically connected to the semiconductors. At least one of the electrically conductive leads is common to both of the semiconductors. The semiconductor module also includes a termination resistor electrically coupled to at least one of the semiconductors. A method of making a semiconductor module is also taught, whereby a plurality of electrically conductive leads are provided. At least two semiconductors are electrically coupled to the plurality of electrically conductive leads, where at least one of the electrically conductive leads is common to both of the semiconductors. The semiconductors are then thermally coupled to a heat spreader. Subsequently, a termination resistor is electrically coupled to at least one of the semiconductors.

1. A semiconductor module, comprising:
 a heat spreader;   at least two semiconductors thermally coupled to said heat spreader;   a plurality of electrically conductive leads electrically connected to said semiconductors, where at least one of said electrically conductive leads is common to both of said semiconductors; and   a termination resistor electrically coupled to at least one of said semiconductors.   
     
     
       2. A semiconductor module according to  claim 1 , wherein said semiconductors are electrically coupled to one another in series, and where said semiconductors are capable of being electrically coupled to a transmission channel. 
     
     
       3. A semiconductor module according to  claim 2 , wherein a final semiconductor in said series, remote from said transmission channel, is electrically coupled to said termination resistor. 
     
     
       4. A semiconductor module according to  claim 1 , wherein one semiconductor of the semiconductors is not connected to said termination resistor, and an additional termination resistor is electrically coupled to the one semiconductor not connected to said termination resistor. 
     
     
       5. A semiconductor module according to  claim 1 , wherein a resistance value of the termination resistor is selected such that an impedance of said termination resistor substantially matches an impedance of a transmission channel and a signal source to which said termination resistor is connected. 
     
     
       6. A semiconductor module according to  claim 1 , wherein said termination resistor's form of termination is selected from a group consisting of: parallel termination, Thevenin termination, series termination, AC termination, and Schotty-diode termination. 
     
     
       7. A semiconductor module according to  claim 1 , wherein said termination resistor is thermally coupled to said heat spreader. 
     
     
       8. A semiconductor module according to  claim 1 , wherein said termination resistor is bonded directly to a side wall of said heat spreader. 
     
     
       9. A semiconductor module according to  claim 1 , wherein said two semiconductors are mounted on opposing side walls of said heat spreader. 
     
     
       10. A semiconductor module according to  claim 2 , wherein each of said semiconductors are bonded directly to said side wall of said heat spreader. 
     
     
       11. A semiconductor module according to  claim 1 , wherein said leads form part of a flexible circuit at least partially attached to said heat spreader. 
     
     
       12. A semiconductor module according to  claim 11 , wherein said flexible circuit is a flexible dielectric tape. 
     
     
       13. A semiconductor module according to  claim 12 , wherein said flexible circuit is bonded directly to said side wall of said heat spreader. 
     
     
       14. A semiconductor module according to  claim 1 , wherein said common electrically conductive lead is selected from a group consisting of a voltage supply node, a reference voltage node, and an electrical ground node. 
     
     
       15. A semiconductor module according to  claim 1 , wherein said heat spreader is a solid block of heat dissipating material. 
     
     
       16. A semiconductor module according to  claim 1 , wherein said heat spreader is “u” shaped. 
     
     
       17. A method of making a semiconductor module, comprising:
 providing a plurality of electrically conductive leads;   electrically coupling at least two semiconductors to said plurality of electrically conductive leads, where at least one of said electrically conductive leads is common to both of said semiconductors;   thermally coupling said semiconductors to a heat spreader; and   electrically coupling a termination resistor to at least one of said semiconductors.   
     
     
       18. A method according to  claim 17 , initially comprising electrically coupling said semiconductors in series, where said semiconductors are capable of being electrically coupled to a transmission channel. 
     
     
       19. A method according to  claim 17 , further comprising electrically coupling an additional termination resistor to the semiconductor not already connected to said termination resistor, where each of said semiconductors is capable of being electrically coupled to a separate transmission channel. 
     
     
       20. A method according to  claim 17 , including bonding said termination resistor directly to a side wall of said heat spreader. 
     
     
       21. A method according to  claim 17 , including mounting said two semiconductors on opposing side walls of said heat spreader. 
     
     
       22. A method according to  claim 17 , including bonding each of said semiconductors directly to a side wall of said heat spreader. 
     
     
       23. A method according to  claim 17 , wherein said leads form part of a flexible circuit at least partially attached to said heat spreader, said method including bonding said flexible circuit directly to a side wall of said heat spreader. 
     
     
       24. A semiconductor module, comprising:
 a heat spreader having at least three substantially planar sides including first and second opposing sides and a third side substantially perpendicular to the first and second sides;   a first semiconductor thermally coupled to the first side, where the first semiconductor includes first circuitry;   a second semiconductor thermally coupled to the second side, where the second semiconductor includes second circuitry;   a flexible circuit, including a plurality of electrically conductive leads electrically connected to the circuitry of the first and second semiconductors, where the flexible circuit is at least partially bonded to the heat spreader and includes a segment of the flexible circuit that is wrapped around the third side of the heat spreader; and   a plurality of electrical contacts disposed on the flexible circuit proximate to the third side of the heat spreader, where respective ones of the plurality of electrical contacts are electrically coupled to respective ones of the plurality of electrically conductive leads, wherein the plurality of electrical contacts are configured to removeably couple the semiconductor module to corresponding electrical contacts formed in a slot on a circuit board when a portion of the semiconductor module, including the third side the heat spreader, the segment of the flexible circuit that is wrapped around the third side of the heat spreader, and at least a portion of each of the plurality of electrical contacts, is inserted into the slot.   
     
     
       25. The semiconductor module according to claim 24, wherein the flexible circuit is flexible tape. 
     
     
       26. The semiconductor module according to claim 24, wherein the flexible circuit is bonded to the heat spreader along the first and second sides. 
     
     
       27. The semiconductor module according to claim 24, further comprising:
 a termination circuit electrically coupled to the circuitry of at least one of the first and second semiconductors, wherein one semiconductor of the semiconductors is not connected to the termination circuit; and   an additional termination circuit electrically coupled to the one semiconductor that is not connected to the termination circuit.   
     
     
       28. The semiconductor module according to claim 24, further comprising a termination circuit electrically coupled to the circuitry of at least one of the first and second semiconductors, wherein the termination circuit is a termination resistor having a resistance value selected such that an impedance of the termination resistor substantially matches an impedance of a transmission channel and a signal source to which the termination resistor is connected. 
     
     
       29. The semiconductor module according to claim 24, further comprising a termination circuit electrically coupled to the circuitry of at least one of the first and second semiconductors, wherein the termination circuit is thermally coupled to the heat spreader. 
     
     
       30. The semiconductor module according to claim 24, further comprising a termination circuit electrically coupled to the circuitry of at least one of the first and second semiconductors, wherein the termination circuit is bonded directly to a side wall of the heat spreader. 
     
     
       31. The semiconductor module according to claim 24, wherein the heat spreader is a solid block of heat dissipating material. 
     
     
       32. The semiconductor module according to claim 24, wherein:
 the heat spreader is configured to removeably mechanically engage directly to a fastening mechanism mounted to the circuit board so as to maintain contact between the plurality of electrical contacts disposed on the flexible circuit and corresponding electrical contacts in the slot on the circuit board.   
     
     
       33. The semiconductor module according to claim 32, wherein the fastening mechanism includes with one or more opposing clamps each engaging with a respective opposite side of the heat spreader for anchoring the semiconductor module to the circuit board. 
     
     
       34. The semiconductor module according to claim 24, wherein the plurality of electrical contacts comprise a plurality of electrical contact pads electrically and mechanically coupled to the plurality of electrically conductive leads. 
     
     
       35. The semiconductor module according to claim 34, wherein the plurality of electrical contact pads are an array of bond pads. 
     
     
       36. The semiconductor module according to claim 34, wherein the plurality of electrical contact pads are an array of metal points. 
     
     
       37. The semiconductor module according to claim 24, wherein the semiconductors are bonded to the heat spreader using a bonding adhesive with thermal expansion properties similar to those of the semiconductors and the heat spreader. 
     
     
       38. The semiconductor module according to claim 24, wherein the plurality of electrically conductive leads are contained within the flexible circuit. 
     
     
       39. The semiconductor module according to claim 24, wherein the flexible circuit is bonded to the heat spreader using a bonding adhesive with thermal expansion properties similar to those of the flexible circuit and the heat spreader. 
     
     
       40. The semiconductor module according to claim 24, wherein the flexible circuit is at least partially bonded to the heat spreader and the semiconductors. 
     
     
       41. The semiconductor module according to claim 24, wherein the semiconductor module is configured to connect to a pin grid array (PGA) socket that in turn connects to a circuit board. 
     
     
       42. The semiconductor module according to claim 24, further comprising shielding to protect the semiconductors from electromagnetic forces. 
     
     
       43. The semiconductor module according to claim 24, further comprising a first set of semiconductors including the first semiconductor, wherein the first set of semiconductors are connected to one another in series. 
     
     
       44. The semiconductor module according to claim 24, wherein the semiconductor module is a memory module. 
     
     
       45. The semiconductor module according to claim 24, wherein when the plurality of electrical contacts on the flexible circuit make contact with the corresponding electrical contacts formed in the slot, the opposing sides of the heat spreader are substantially perpendicular to the circuit board. 
     
     
       46. The semiconductor module according to claim 24, wherein the plurality of electrical contacts are substantially equally distanced from the first and second semiconductors. 
     
     
       47. The semiconductor module according to claim 24, wherein the flexible circuit includes a flexible tape having opposing first and second sides, the first side of the flexible tape facing the heat spreader, and wherein the plurality of electrically conductive leads are disposed on the second side of the flexible tape. 
     
     
       48. The semiconductor module according to claim 24, wherein the flexible circuit is bonded to the heat spreader along the first and second sides of the heat spreader, and the first and second semiconductors are bonded to the flexible circuit and thermally coupled to the heat spreader through the flexible circuit. 
     
     
       49. A semiconductor module, comprising:
 a heat spreader having at least one edge;   a plurality of semiconductors that are thermally coupled to the heat spreader, wherein each semiconductor of the plurality of semiconductors is connected to its own transmission channel and each transmission channel is separately terminated;   a flexible circuit electrically coupled to the plurality of semiconductors, having a segment that is wrapped around the edge of the heat spreader; and   a plurality of electrical contacts disposed on the flexible circuit proximate to the edge of the heat spreader, where the plurality of electrical contacts are electrically coupled to the semiconductors via the flexible circuit, wherein the plurality of electrical contacts are configured to removeably couple the semiconductor module to corresponding electrical contacts formed in a slot on a circuit board when a portion of the semiconductor module, including the edge of the heat spreader, the segment of the flexible circuit that is wrapped around the edge of the heat spreader, and at least a portion of each of the plurality of electrical contacts, is inserted into the slot.   
     
     
       50. The semiconductor module according to claim 49, further comprising a plurality of termination circuits, each transmission channel having its own termination circuit, wherein the termination circuits are termination resistors, and resistance values of the termination resistors are selected such that the impedances of the termination resistors substantially matches an impedance of a transmission channel and a signal source to which the termination resistor is connected. 
     
     
       51. The semiconductor module according to claim 49, further comprising a plurality of termination circuits, each transmission channel having its own termination circuit, wherein the termination circuits are thermally coupled to the heat spreader. 
     
     
       52. The semiconductor module according to claim 49, further comprising a plurality of termination circuits, each transmission channel having its own termination circuit, wherein the termination circuits are bonded directly to a side wall of the heat spreader. 
     
     
       53. The semiconductor module according to claim 49, wherein the heat spreader is a solid block of heat dissipating material. 
     
     
       54. The semiconductor module according to claim 49, wherein the flexible circuit is bonded to the heat spreader using a bonding adhesive with thermal expansion properties similar to those of the flexible circuit and the heat spreader. 
     
     
       55. The semiconductor module according to claim 49, wherein:
 the plurality of semiconductors includes:
 a first set of two semiconductors each comprising circuitry, where the semiconductors are thermally coupled to the heat spreader; 
 a second set of two semiconductors each comprising circuitry, where the semiconductors are thermally coupled to the heat spreader; and 
   the plurality of electrically conductive leads includes:
 a first set of electrically conductive leads electrically connected to the semiconductors of the first set of semiconductors, where a first common lead of the first set of electrically conductive leads is common to both of the semiconductors of the first set of semiconductors; and 
 a second set of electrically conductive leads electrically connected to the semiconductors of the second set of semiconductors, where a second common lead of the second set of electrically conductive leads is common to both of the semiconductors of the second set of semiconductors, wherein the first common lead is distinct from second common lead. 
   
     
     
       56. The semiconductor module according to claim 49, wherein the semiconductor module is a memory module. 
     
     
       57. The semiconductor module according to claim 49, wherein the heat spreader comprises a solid block of heat spreading material with substantially planar opposing sides that are substantially perpendicular to the edge of the heat spreader; and when the electrical contacts on the flexible circuit are coupled with the corresponding electrical contacts formed in the slot, the substantially planar opposing sides of the heat spreader are substantially perpendicular to the circuit board. 
     
     
       58. A method of making a semiconductor module, comprising:
 thermally coupling a first semiconductor to a first side of a heat spreader;   thermally coupling a second semiconductor to a second side of the heat spreader, where the second side is opposite the first side;   electrically coupling circuitry of the first and second semiconductors to a flexible circuit including a plurality of electrically conductive leads, where at least one of the electrically conductive leads is common to both of the semiconductors, where a segment of the flexible circuit is wrapped around an edge of the heat spreader, where the edge of the heat spreader is between the first side and the second side; and   electrically coupling a plurality of electrical contacts to the plurality of electrically conductive leads, where the electrical contacts are disposed on the flexible circuit proximate to the edge of the heat spreader, wherein the plurality of electrical contacts are configured to removeably couple the semiconductor module to corresponding electrical contacts formed in a slot on a circuit board when a portion of the semiconductor module, including the edge the heat spreader, the segment of the flexible circuit that is wrapped around the edge of the heat spreader, and at least a portion of each of the plurality of electrical contacts, is inserted into the slot.   
     
     
       59. The method according to claim 58, further comprising: electrically coupling a termination circuit to the circuitry of at least one of the semiconductors, wherein the plurality of electrically conductive leads are bonded to at least a portion of the first side, the second side, and the edge of the heat spreader, wherein the edge of the heat spreader is substantially perpendicular to and connects the first and second sides. 
     
     
       60. A method according to claim 58, initially comprising electrically coupling the semiconductors in series, where the semiconductors are capable of being electrically coupled to a transmission channel. 
     
     
       61. A method according to claim 58, further comprising:
 electrically coupling a termination circuit to the circuitry of at least one of the semiconductors; and   electrically coupling an additional termination circuit to the semiconductor not already connected to the termination circuit, where each of the semiconductors is capable of being electrically coupled to a separate transmission channel.   
     
     
       62. A method according to claim 58, further comprising electrically coupling a termination circuit to the circuitry of at least one of the semiconductors, wherein the termination circuit is bonded directly to the first side or the second side of the heat spreader. 
     
     
       63. A method according to claim 58, including bonding each of the semiconductors directly to the first side or the second side of the heat spreader. 
     
     
       64. A method according to claim 58, including:
 electrically coupling circuitry of a first plurality of semiconductors to the plurality of electrically conductive leads of the flexible circuit, wherein the first plurality of semiconductors includes the first semiconductor and the plurality of electrically conductive leads includes a first common lead that is common to the semiconductors in the first set of semiconductors; and   electrically coupling circuitry of a second plurality of semiconductors to the plurality of electrically conductive leads of the flexible circuit, wherein the second plurality of semiconductors includes the second semiconductor and the plurality of electrically conductive leads includes a second common lead that is common to the semiconductors in the second set of semiconductors, wherein the first common lead is distinct from the second common lead.   
     
     
       65. The method according to claim 58 wherein the heat spreader comprises a solid block of heat spreading material with substantially planar opposing sides that are substantially perpendicular to the edge of the heat spreader; and when the electrical contacts on the flexible circuit are coupled with the corresponding electrical contacts in the slot, the substantially planar opposing sides of the heat spreader are substantially perpendicular to the circuit board.