Microelectronic assembly with impedance controlled wirebond and reference wirebond
View Patent ↗A microelectronic assembly can include a microelectronic device, e.g., semiconductor chip, connected together with an interconnection element, e.g., substrate, the latter having signal contacts and reference contacts. The reference contacts can be connectable to a source of reference potential such as ground or a voltage source other than ground such as a voltage source used for power. Signal conductors, e.g., signal wirebonds can be connected to device contacts exposed at a surface of the microelectronic device. Reference conductors, e.g., reference wirebonds can be provided, at least one of which can be connected with two reference contacts of the interconnection element. The reference wirebond can have a run which extends at an at least substantially uniform spacing from a signal conductor, e.g., signal wirebond that is connected to the microelectronic device over at least a substantial portion of the length of the signal conductor. In such manner a desired impedance may be achieved for the signal conductor.
1. A microelectronic assembly comprising:
a microelectronic device having device contacts exposed at a surface thereof;
an interconnection element having a plurality of signal contacts and a plurality of reference contacts, the reference contacts being connectable to a source of reference potential;
signal conductors connecting the device contacts with the signal contacts, the signal conductors having substantial portions extending in runs above the surface of the microelectronic device; and
reference conductors connected to the reference contacts and having substantial portions extending in runs spaced at an at least substantially uniform spacing from the runs of the signal conductors, at least one of the reference conductors being connected to two reference contacts of the interconnection element, such that a desired impedance is achieved for the signal conductors.
2. A microelectronic assembly comprising:
a microelectronic device having device contacts on a surface thereof;
an interconnection element having a plurality of signal contacts and a plurality of reference contacts, the reference contacts being connectable to a source of reference potential;
signal conductors connecting the device contacts with the signal contacts, the signal conductors having substantial portions extending in runs above the surface of the microelectronic device; and
reference conductors connected to the reference contacts and extending at least substantially in parallel with appreciable portions of the runs of the signal conductors, the reference conductors being disposed at least one of above the signal conductors or below the signal conductors, at least one of the reference conductors being connected to two reference contacts of the interconnection element, such that a desired impedance is achieved for the signal conductors.
3. A microelectronic assembly as claimed in claim 1 or claim 2 , wherein the runs of at least some of the signal conductors extend in a first plane and at least some of the reference conductors have appreciable portions extending in a second plane which is at least substantially parallel to the first plane.
4. A microelectronic assembly as claimed in claim 1 or claim 2 , wherein appreciable portions of the reference conductors extend at least substantially parallel to the runs of the signal conductors over at least about 50% of the length of the runs of the signal conductors.
5. A microelectronic assembly as claimed in claim 1 or claim 2 , wherein the signal conductors include signal bond wires and the reference conductors include reference bond wires.
6. A microelectronic assembly as claimed in claim 1 or claim 2 , wherein the signal conductors are signal bond wires and the reference conductors are reference bond wires.
7. A microelectronic assembly as claimed in claim 6 , wherein at least one of the reference bond wires is bonded to respective reference contacts of the interconnection element.
8. A microelectronic assembly as claimed in claim 1 , wherein the reference bond wires include first reference bond wires disposed at a greater height from the microelectronic device than the signal bond wires, second reference bond wires disposed at a lower height from the microelectronic device than the signal bond wires, and third reference bond wires interposed between individual ones of the signal bond wires.
9. A microelectronic assembly as claimed in claim 5 , wherein the reference bond wires have first ends and second ends remote from the first ends, at least one of the reference bond wires having a first end connected to a reference contact and a second end connected to a device contact.
10. A microelectronic assembly as claimed in claim 6 , wherein the surface is a front surface, the microelectronic device has a rear surface remote from the front surface and edges extending between the front and rear surfaces, the rear surface being mounted to the interconnect element such that the signal bond wires and reference bond wires extend beyond the edges of the microelectronic device.
11. A microelectronic assembly as claimed in claim 6 , wherein at least some of the runs are canted at an angle relative to the surface of the microelectronic device.
12. A microelectronic assembly as claimed in claim 5 , wherein the plurality of runs includes at least portions of bond wires.
13. A microelectronic assembly as claimed in claim 12 , wherein at least one of the signal bond wires extends in a stepwise manner as a plurality of connected steps, and at least one of the reference bond wires extends in a stepwise manner at an at least substantially uniform spacing from at least some steps of such signal bond wire.
14. A microelectronic assembly as claimed in claim 13 , wherein the runs of at least some of the signal conductors extend in a first plane and at least some of the reference conductors have appreciable portions extending in a second plane which is at least substantially parallel to the first plane.
15. A microelectronic assembly as claimed in claim 13 , wherein appreciable p ortions of the reference conductors extend at least substantially parallel to the runs of the signal conductors over at least about 50% of the length of the runs of the signal conductors.
16. A microelectronic assembly as claimed in claim 13 , wherein the signal conductors include signal bond wires and the reference conductors include reference bond wires.
17. A microelectronic assembly as claimed in claim 13 , wherein the signal conductors are signal bond wires and the reference conductors are reference bond wires.
18. A microelectronic assembly as claimed in claim 17 , wherein at least one of the reference bond wires is bonded to respective reference contacts of the interconnection element.
19. A microelectronic assembly as claimed in claim 16 , wherein the reference bond wires have first ends and second ends remote from the first ends, at least one of the reference bond wires having a first end connected to a reference contact and a second end connected to a device contact.
20. A microelectronic assembly as claimed in claim 17 , wherein the surface is a front surface, the microelectronic device has a rear surface remote from the front surface and edges extending between the front and rear surfaces, the rear surface being mounted to the interconnect element such that the signal bond wires and reference bond wires extend beyond the edges of the microelectronic device.
21. A microelectronic assembly as claimed in claim 17 , wherein at least some of the runs are canted at an angle relative to the surface of the microelectronic device.
22. A microelectronic assembly as claimed in claim 16 , wherein the plurality of runs includes at least portions of bond wires.
23. A microelectronic assembly as claimed in claim 22 , wherein at least one of the signal bond wires extends in a stepwise manner as a plurality of connected steps,