Method and apparatus for making a determination relating to resistance of probes

1. A method of determining a resistance of probes on a contactor device comprising a plurality of probes ones of which are disposed to contact an electronic device to be tested, the method comprising:

electrically connecting a pair of the probes directly one to another;

forcing with a force module located on the contactor device one of a voltage onto or a current through the pair of the probes;

sensing at a location on the contactor device with a sense module located on the contactor device the other of a voltage across or a current through the pair of the probes; and

approximating a contact resistance of ones of the probes from the one of the voltage or the current forced onto or through the pair of the probes and the other of the voltage or the current sensed across or through the pair of the probes.

2. The method of claim 1 , wherein the electrically connecting comprises bringing the pair of the probes into contact with a conductive structure on the electronic device to be tested.

3. The method of claim 2 , wherein the conductive structure comprises a terminal on the electronic device, and the terminal is electrically isolated from circuit elements of the electronic device.

4. The method of claim 2 , wherein the electronic device comprises a semiconductor wafer comprising a plurality of dies, and the conductive structure is disposed in a scribe street of the wafer.

5. The method of claim 1 , wherein the location at which the one of the voltage or the current is sensed is on a surface of the contactor device to which the probes of the contactor device are attached.

6. The method of claim 1 , wherein the location at which the one of the voltage or the current is sensed is part of a substrate to which the probes of the contactor device are attached.

7. The method of claim 1 , wherein the location at which the one of the voltage or the current is sensed is within about six inches of the pair of the probes.

8. The method of claim 1 , wherein the location at which the one of the voltage or the current is sensed is within about two inches of the pair of the probes.

9. The method of claim 1 , wherein the location at which the one of the voltage or the current is sensed includes locations on electrical connections to the pair of the probes.

10. The method of claim 1 further comprising counting a number of touchdowns of ones of the probes onto electronic devices to be tested.

11. The method of claim 10 further comprising repeating the approximating a contact resistance every N number of touchdowns counted.

12. The method of claim 11 further comprising storing in a digital memory data relating to a number of touchdowns counted, a time associated with at least one of the touchdowns, and an approximated contact resistance associated with at least one of the touchdowns.

13. The method of claim 1 , wherein the contactor device comprises a probe card assembly.

14. The method of claim 13 , wherein the probe card assembly comprises a probe substrate on which ones of the probes are disposed, and the location at which the sensing is performed is on the probe substrate.

15. The method of claim 1 , wherein each probe in the pair of the probes is one of the probes disposed to contact the electronic device to be tested.

16. The method of claim 1 , wherein sensing at a location on the contactor device comprises providing an output signal proportional to the other of a voltage across or a current through the pair of the probes.

17. The method of claim 1 , wherein the approximating is performed by a measurement module located on the contactor device.

18. The method of claim 1 , wherein the electrically connecting the pair of probes comprises electrically shorting the probes one to another.

19. The method of claim 18 , wherein the electrically shorting the probes one to another comprises bringing the pair of probes into contact with a single conductive structure.

20. The method of claim 18 , wherein the electrically shorting the probes one to another comprises bringing the pair of probes into contact with conductive structures that are directly connected one to another by an electrically conductive trace.

21. A probe card assembly comprising:

a structure;

an electrical interface disposed on the structure and configured to make electrical connections with communications channels to a tester;

a plurality of probes disposed on the structure, ones of the probes being electrically connected to the electrical interface and disposed to contact an electronic device to be tested;

forcing means for forcing one of a voltage onto or a current through a pair of the probes, the forcing means being disposed on the structure; and

sensing means for sensing the other of a voltage across or a current through the pair of the probes, the sensing means being disposed on the structure; and

means for approximating a contact resistance of ones of the probes from the one of the voltage or the current forced onto or through the pair of the probes and the other of the voltage or the current sensed across or through the pair of the probes.

22. The probe card assembly of claim 21 , wherein the pair of the probes is disposed to contact a conductive structure on the electronic device to be tested.

23. The probe card assembly of claim 21 , wherein the sensing means senses the other of the voltage or the current at electrical connections to the pair of the probes.

24. The probe card assembly of claim 21 , wherein the electrical connections to the pair of the probes are part of a substrate to which the probes are attached.

25. The probe card assembly of claim 21 further comprising counting means for counting a number of touchdowns of ones of the probes onto electronic devices to be tested.

26. The probe card assembly of claim 25 , wherein the approximating means approximates the contact resistance of the ones of the probes after the counting means counts a predetermined number N of touchdowns.

27. The probe card assembly of claim 26 further comprising a digital memory configured to store data relating to a number of touchdowns counted by the counting means, a time associated with at least one of the touchdowns, and an approximated contact resistance associated with at least one of the touchdowns.

28. The probe card assembly of claim 21 , wherein the structure comprises:

a wiring board on which the electrical interface is disposed;

a probe substrate to which the probes are attached; and

electrical connections between the wiring board and the probe substrate.

29. The probe card assembly of claim 28 , wherein the sensing means is disposed on the probe substrate.

30. The probe card assembly of claim 29 , wherein the forcing means is disposed on the probe substrate.

31. The probe card assembly of claim 21 , wherein the structure is configured to be attached to and detached from a housing in which a holder for the electronic device is located.

32. The probe card assembly of claim 21 , wherein each probe in the pair of the probes is one of the probes electrically connected to the interface and disposed to contact the electronic device to be tested.

33. The probe card assembly of claim 21 , wherein said sensing means provides an output signal proportional to the other of a voltage across or a current through the pair of the probes.

34. The probe card assembly of claim 21 , wherein the means for approximating a contact resistance is disposed on the structure.