High performance probe system

• US 7,227,371 B2
• Filed: 11/14/2005
• Issued: 06/05/2007
• Est. Priority Date: 05/08/2002
• Status: Expired due to Term

• Current Assignee: FormFactor Incorporated
• Original Assignee: FormFactor Incorporated
• Inventors: Miller, Charles A.
• Primary Examiner(s): HOLLINGTON, JERMELE M
• Application Number:
  US11/273,889
• Publication Number:
  US 20060066332A1
• Time in Patent Office: 568 Days
• Field of Search: None
• US Class Current: 324/754.14
• CPC Class Codes: G01R 1/07314 the body of the probe being perpendicular to test object, e.g. bed of nails or probe with bump contacts on a rigid support on an elastic support, e.g. a film, G01R1/0735
• CPC Class Codes: G01R 1/07378 using an intermediate adapter, e.g. space transformers G01R1/07371 takes precedence
• CPC Class Codes: G01R 31/2889 Interfaces, e.g. between probe and tester G01R31/31905 and G01R1/07364 take precedence
• CPC Class Codes: G01R 31/31905 Interface with the device under test [DUT], e.g. arrangements between the test head and the DUT, mechanical aspects, fixture
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

A probe system for providing signal paths between an integrated circuit (IC) tester and input/output, power and ground pads on the surfaces of ICs to be tested includes a probe board assembly, a flex cable and a set of probes arranged to contact the IC'"'"'s I/O pads. The probe board assembly includes one or more rigid substrate layers with traces and vias formed on or within the substrate layers providing relatively low bandwidth signal paths linking the tester to probes accessing some of the IC'"'"'s pads. The flex cable provides relatively high bandwidth signal paths linking the tester to probes accessing others of the IC'"'"'s pads.

Claims

1. An apparatus for testing integrated circuits (ICs) with first and second IC testers that provide low frequency signals and high frequency signals to pads of an IC to be tested, the apparatus comprising:

a first substrate;

a second substrate having conductive probes for contacting the IC pads;

a flexible cable residing between, and spaced apart from the first and second substrates, the flexible cable conductively connected to the first and second IC testers;

a first signal path for selectively conveying signals between the flexible cable and the IC pads through the second substrate;

a second signal path for conveying signals between the flexible cable and the first IC tester through the first substrate;

a third signal path for conveying signals through the flexible cable to the second IC tester; and

an active routing switch for selectively coupling the second and third signal paths to the first signal path.

2. The apparatus in accordance with claim 1

wherein said the first signal path comprises a first spring contact extending between the flexible cable and second substrate, and

wherein the second signal path comprises a second spring contact extending between the first substrate and the flexible cable.

3. The apparatus in accordance with claim 1 wherein the active routing switch is mounted on the flexible cable.

4. The apparatus in accordance with claim 1 further comprising a fourth signal path extending from one of the first and second IC testers to said active routing switch for conveying a control signal controlling which of said second and third signal paths said active routing switch is to selectively couple to the first signal path.

5. An apparatus for testing integrated circuits (ICs) with an IC tester by providing low frequency signals and high frequency signals from the IC tester to pads of an IC to be tested, the apparatus comprising:

a first substrate with the probes mounted thereon for connecting to the IC pads;

a flexible cable conductively linked from the IC tester to a first portion of the IC pads, the flexible cable carrying the high frequency signals; and

connectors for providing a conductive link between the IC tester through the first substrate to a second portion of the IC pads, the connectors carrying the low frequency signals.

6. The apparatus in accordance with claim 5 wherein the probes comprise spring contacts.

7. The apparatus of claim 5, the flexible cable further comprising conductive substrate fingers that extend in the space between the first substrate and the ICs.

8. The apparatus of claim 7, the first substrate further comprising one or more structural members for attaching to one or more points on the conductive substrate fingers so as to inhibit freedom of movement of the fingers relative to the first substrate.

9. The apparatus of claim 7, wherein each conductive substrate finger contacts one of the IC pads.

10. The apparatus of claim 7, wherein each conductive substrate finger contacts a plurality of the IC pads.

11. The apparatus of claim 7, wherein the conductive substrate fingers bypass at least one of the probes on a lower surface of the first substrate, wherein the bypassed probe is used for testing the ICs using the low frequency signals.

12. The apparatus of claim 7, wherein the conductive substrate fingers include pointed conductive tips formed on the underside of the fingers, the pointed conductive tips for contacting the IC pads.

13. The apparatus of claim 8, wherein the one or more structural members extend from a lower surface of the first substrate.

14. The apparatus of claim 8, wherein the one or more structural members attach to an upper surface of the substrate fingers.

15. The apparatus of claim 8, wherein the one or more structural members are not conductive.

16. The apparatus of claim 8, wherein the one or more structural members comprise spring contacts.

17. The apparatus of claim 5, further comprising a second substrate that carries the low frequency signals from the IC tester to the first substrate.

18. The apparatus of claim 17, wherein the second substrate is connected to receive the high frequency signals from the IC tester, and the flexible cable connects the second substrate to the IC pads.

19. The apparatus of claim 5, wherein the flexible cable connects to the IC pads via traces on or in the ICs.

20. The apparatus of claim 5, wherein the flexible cable resides between and spaced apart from the first substrate and the ICs, the flexible cable comprising an aperture, wherein a conductive first bypass probe links the first substrate to the IC to be tested, the first probe passing through the aperture in the flexible cable.

21. The apparatus of claim 20, wherein the first substrate comprises one or more structural members for attaching to one or more points on the flexible cable so as to inhibit freedom of movement of the flexible cable relative to the first substrate.

22. The apparatus of claim 20, wherein the flexible cable comprises conductive probe tips formed on a lower surface of the flexible cable for contacting the IC pads.

23. The apparatus of claim 21, wherein the one or more structural members extend from a lower surface of the first substrate.

24. The apparatus of claim 21, wherein the one or more structural members attach to an upper surface of the flexible cable.

25. The apparatus of claim 21, wherein the one or more structural members are not conductive.

26. The apparatus of claim 21 wherein the one or more structural members comprise spring contacts.

27. The apparatus of claim 20, wherein the flexible cable is connected to the IC pads via traces on or in the ICs.

28. The apparatus of claim 20, further comprising a second substrate which connects the flexible cable to the IC tester.

29. The apparatus of claim 20, wherein the flexible cable comprises an island of flexible cable material within each aperture of the flexible cable, each island connected to the flexible cable by a plurality of bridges of flexible cable material and surrounding the bypass probe within the aperture.

30. An apparatus for testing integrated circuits (ICs) with an IC tester by providing low frequency signals and high frequency signals from the IC tester to pads of an IC to be tested, the apparatus comprising:

a flexible cable conductively connected to the IC tester to receive the high frequency signals; and

means for conductively connecting the flexible cable to the IC pads.

31. The apparatus of claim 30, wherein the flexible cable is connected to the IC pads via traces in or on the ICs.

32. An apparatus for testing integrated circuits (ICs) with an IC tester by providing low frequency signals and high frequency signals from the IC tester to pads of an IC to be tested, the apparatus comprising:

a first substrate with the probes mounted thereon for connecting to the IC pads;

a flexible cable conductively linked from the IC tester to a portion of the substrate probes, the flexible cable carrying the high frequency signals; and

connectors for providing a conductive link between the IC tester through the first substrate to a portion of the IC pads, the connectors carrying the low frequency signals.

33. The apparatus in accordance with claim 32, wherein the flexible cable is connected to the portion of the substrate probes via traces on or in the first substrate.