Microelectronic assembly with impedance controlled wirebond and reference wirebond
View Patent ↗A microelectronic device, e.g., semiconductor chip, is connected with an interconnection element having signal contacts and reference contacts, the reference contacts being connectable to a reference potential such as ground or power. Signal conductors, e.g., signal wirebonds can be connected to device contacts of the microelectronic device, and at least one reference conductor, e.g., reference wirebond can be connected with two reference contacts. The reference wirebond can have a run extending at an at least substantially uniform spacing from an at least a substantial portion of a length of a signal conductor, e.g., signal wirebond. In such manner a desired impedance may be achieved for the signal conductor.
1. The 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;
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; and
a dielectric encapsulation contacting and encapsulating the signal conductors and the reference conductors.
2. The microelectronic assembly as claimed in claim 1 , wherein the signal conductors include signal bond wires and the reference conductors include reference bond wires.
3. The microelectronic assembly as claimed in claim 1 , wherein the signal conductors are signal bond wires and the reference conductors are reference bond wires.
4. The microelectronic assembly as claimed in claim 2 , wherein the surface is a front surface, and 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 the reference bond wires extend beyond the edges of the microelectronic device.
5. The microelectronic assembly as claimed in claim 4 , wherein the runs of at least some of the signal bond wires extend in a first plane and at least some of the reference bond wires have appreciable portions extending in a second plane which is at least substantially parallel to the first plane.
6. The microelectronic assembly as claimed in claim 4 , wherein appreciable portions of the reference bond wires extend at least substantially parallel to the runs of the signal bond wires over at least about 50% of the length of the runs of the signal bond wires.
7. The microelectronic assembly as claimed in claim 4 , wherein the reference bond wires include reference bond wires disposed at a greater height from the front surface of the microelectronic device than the signal bond wires.
8. The microelectronic assembly as claimed in claim 4 , wherein the reference bond wires include reference bond wires disposed at a lower height from the front surface of the microelectronic device than the signal bond wires.
9. The microelectronic assembly as claimed in claim 2 , wherein the reference bond wires include first reference bond wires disposed at a greater height from the front surface of the microelectronic device than the signal bond wires, second reference bond wires disposed at a lower height from the front surface of the microelectronic device than the signal bond wires, and third reference bond wires interposed between individual ones of the signal bond wires.
10. The microelectronic assembly as claimed in claim 2 , 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.
11. The microelectronic assembly as claimed in claim 2 , wherein at least some of the runs are canted at an angle relative to the surface of the microelectronic device.
12. The microelectronic assembly as claimed in claim 2 , 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.
13. The microelectronic assembly as claimed in claim 4 , wherein the interconnection element is a dielectric element bearing a plurality of traces extending along the dielectric element, the traces connected to the reference contacts and the signal contacts.
14. The microelectronic assembly as claimed in claim 13 , wherein the interconnection element is a sheet-like dielectric element, the dielectric element having metal traces and a plurality of bond pads patterned thereon, the signal contacts and the reference contacts being bond pads of the plurality of bond pads.
15. The microelectronic assembly comprising:
a dielectric element having a surface and plurality of signal contacts and a plurality of reference contacts, the signal contacts and the reference contacts exposed at the surface, the reference contacts being connectable to a source of reference potential;
a microelectronic device having a rear surface, a front surface remote from the rear surface and edges extending between the front and rear surfaces, the rear surface being mounted to the surface of the dielectric element, the microelectronic device having a plurality of contacts exposed at the front surface;
signal bond wires connecting the device contacts with the signal contacts, the signal bond wires having substantial portions extending in runs above the front surface of the microelectronic device;
reference bond wires 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 bond wires, at least one of the reference bond wires being connected to two reference contacts of the interconnection element, such that a desired impedance is achieved for the signal bond wires,
wherein the signal bond wires and the reference bond wires extend beyond the edges of the microelectronic device,
the microelectronic assembly further comprising a dielectric encapsulation contacting and encapsulating the signal bond wires and the reference bond wires.
16. The microelectronic assembly as claimed in claim 15 , wherein the runs of at least some of the signal bond wires extend in a first plane and at least some of the reference bond wires have appreciable portions extending in a second plane which is at least substantially parallel to the first plane.
17. The microelectronic assembly as claimed in claim 15 , wherein appreciable portions of the reference bond wires extend at least substantially parallel to the runs of the signal bond wires over at least about 50% of the length of the runs of the signal bond wires.
18. The microelectronic assembly as claimed in claim 15 , wherein the reference bond wires include reference bond wires disposed at a greater height from the front surface of the microelectronic device than the signal bond wires.
19. The microelectronic assembly as claimed in claim 15 , wherein the reference bond wires include reference bond wires disposed at a lower height from the front surface of the microelectronic device than the signal bond wires.
20. The microelectronic assembly as claimed in claim 15 , wherein the reference bond wires include first reference bond wires disposed at a greater height from the front surface of the microelectronic device than the signal bond wires, second reference bond wires disposed at a lower height from the front surface of the microelectronic device than the signal bond wires, and third reference bond wires interposed between individual ones of the signal bond wires.