Transmission line coupler for testing of integrated circuits
View Patent ↗The present disclosure describes a semiconductor wafer testing environment for routing signals used for testing integrated circuits formed onto a semiconductor wafer. The semiconductor wafer testing environment includes a semiconductor wafer tester to control overall operation and/or configuration of the semiconductor wafer testing environment and a semiconductor wafer prober to test the integrated circuits formed onto the semiconductor wafer. The semiconductor wafer prober includes a probe card having a transmission line coupler formed onto a flexible substrate. The transmission line coupler includes multiple transmission line coupling blocks that extend radially from a central point of the flexible substrate in a circular manner.
1. A transmission line coupling circuit, comprising:
a flexible substrate; and
a plurality of transmission line coupling blocks formed onto the flexible substrate in a circular manner around a central point of the flexible substrate, the plurality of transmission line coupling blocks comprising:
a plurality of first coupled transmission lines implemented on a top side of the flexible substrate and connected to the central point,
a plurality of first conductive traces implemented on the top side of the flexible substrate and connected between the plurality of first coupled transmission lines and a plurality of ports,
a plurality of second coupled transmission lines implemented on a bottom side of the flexible substrate and connected to a plurality of vias, and
a plurality of second conductive traces implemented on the top side of the flexible substrate and connected between the plurality of vias and a plurality of load resistors.
2. The transmission line coupling circuit of claim 1 , wherein the plurality of first coupled transmission lines and the plurality of second coupled transmission lines each comprises:
conductive foil material.
3. The transmission line coupling circuit of claim 1 , wherein the plurality of load resistors comprises:
a plurality of surface mount resistors.
4. The transmission line coupling circuit of claim 1 , wherein the flexible substrate comprises:
polyimide.
5. The transmission line coupling circuit of claim 1 , wherein the plurality of load resistors is configured to match impedances present on the plurality of ports to an internal impedance of the transmission line coupling circuit.
6. The transmission line coupling circuit of claim 1 , wherein the plurality of second coupled transmission lines is not connected to the central point.
7. The transmission line coupling circuit of claim 1 , wherein the plurality of first coupled transmission lines and the plurality of second coupled transmission lines are configured to form a plurality of transmission line couplers.
8. The transmission line coupling circuit of claim 1 , wherein dimensions of first coupled transmission lines and the plurality of second coupled transmission lines are fractionally related to a wavelength of signals routed by the transmission line coupling circuit.
9. A probe card for testing a plurality of integrated circuits formed onto a semiconductor substrate forming a semiconductor wafer, the probe card comprising:
a plurality of mechanical probes configured to contact a plurality of contact pads on the semiconductor wafer; and
a plurality of transmission line coupling circuits connected to the plurality of mechanical probes, the plurality of transmission line coupling circuits configured to route a plurality of testing signals between the semiconductor wafer and a semiconductor wafer tester,
wherein a transmission line coupling circuit from among the plurality of transmission line coupling circuits comprises:
a flexible substrate,
a plurality of transmission line coupling blocks formed onto the flexible substrate in a circular manner around a central point of the flexible substrate, the plurality of transmission line coupling blocks comprising:
a plurality of first coupled transmission lines implemented on a top side of the flexible substrate and connected to the central point,
a plurality of first conductive traces implemented on the top side of the flexible substrate and connected between the plurality of first coupled transmission lines and a plurality of ports, one or more of the plurality of ports being configured to route one or more testing signals from among the plurality of testing signals between the semiconductor wafer and the semiconductor wafer tester,
a plurality of second coupled transmission lines implemented on a bottom side of the flexible substrate and connected to a plurality of vias, and
a plurality of second conductive traces implemented on the top side of the flexible substrate and connected between the plurality of vias and a plurality of load resistors.
10. The probe card of claim 9 , wherein the plurality of first coupled transmission lines and the plurality of second coupled transmission lines each comprises:
thin film deposition.
11. The probe card of claim 9 , wherein the plurality of load resistors comprises:
a plurality of surface mount resistors.
12. The probe card of claim 9 , wherein the flexible substrate comprises:
polyimide.
13. The probe card of claim 9 , wherein the plurality of load resistors is configured to match impedances present on the plurality of ports to an internal impedance of the transmission line coupling circuit.
14. The probe card of claim 9 , wherein the plurality of second coupled transmission lines is not connected to the central point.
15. The probe card of claim 9 , wherein the plurality of first coupled transmission lines and the plurality of second coupled transmission lines are configured to form a plurality of transmission line couplers.
16. The probe card of claim 9 , wherein dimensions of first coupled transmission lines and the plurality of second coupled transmission lines are fractionally related to a wavelength of the plurality of testing signals.
17. A transmission line coupling block of a transmission line coupling circuit, the transmission line coupling block comprising:
a transmission line coupler having a first coupled transmission line and a second coupled transmission line; and
a flexible substrate having a top side and a bottom side,
wherein the first coupled transmission line is implemented on the top side of the flexible substrate and the second coupled transmission line is implemented on the bottom side of the flexible substrate,
a first conductive trace connected between a port and the first coupled transmission line, and
a second conductive trace connected between a load resistor and a via, the via being connected to the second coupled transmission line,
wherein the transmission line coupling block is from among a plurality of transmission line coupling blocks, the plurality of transmission line coupling blocks formed onto the flexible substrate in a circular manner around a central point of the flexible substrate.
18. The transmission line coupling block of claim 17 , wherein the flexible substrate comprises:
polyimide.
19. The transmission line coupling block of claim 17 , wherein the first coupled transmission line is connected to the central point, and
wherein the second coupled transmission line is not connected to the central point.