Probe and method for testing a populated circuit board

• US 4,963,821 A
• Filed: 04/14/1989
• Issued: 10/16/1990
• Est. Priority Date: 04/14/1989
• Status: Expired due to Term

• Current Assignee: Tektronix Incorporated (Fortive Corp.), The Boeing Co.
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: Sekulic, Zoran O., Bitetto, Mark F., Janko, Bozidar
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Nguyen, Vinh P.
• Application Number:
  US07/338,786
• Time in Patent Office: 550 Days
• Field of Search: 324/158 F, 324/158 P, 324/73 PC, 324/72.5, 361/386, 361/387, 361/398, 439/482
• US Class Current: 324/754.03
• CPC Class Codes: G01R 1/07307 with individual probe elements, e.g. needles, cantilever beams or bump contacts, fixed in relation to each other, e.g. bed of nails fixture or probe card

Abstract

A probe includes a flexible sheet of dielectric material having an opening therein sized and shaped to receive an electronic component mounted on a support member at a major surface thereof, a contact pad exposed at a first main face of the sheet and adjacent the opening therein, and a conductor connecting the contact pad to a terminal of the probe. The probe is positioned with its first main face in confronting relationship with the major surface of the support member and with the opening in the sheet in registration with the electronic component, and pressure is applied to the flexible sheet to bring the contact pad into contact with the test point.

Claims

1. A probe for testing a populated circuit board that comprises a support member having a major surface, and an electronic component which is mounted on the support member at the major surface thereof and has a topp surface spaced from the major surface of the support member, the circuit board having a test point exposed at the major surface adjacent said component, the test point having a top surface that is closer to the major surface of the circuit board than is the top surface of the electronic component, said probe comprising a flexible sheet of dielectric material having first and second main faces and formed with an opening extending therethrough and sized and shaped to receive the electronic component, at least one contact pad exposed at the first main face of the flexible sheet, and at least one conductor run adhered to the flexible sheet and connecting the contact pad to a probe terminal.

2. A probe according to claim 1, wherein the probe comprises a plurality of contact pads exposed at the first main face of the flexible sheet about the opening in the sheet in a predetermined pattern, and a plurality of conductors adhered to the flexible sheet and connecting the contact pads to respective probe terminals, so that when the first main face of the probe is placed in confronting relationship with a circuit board that has a plurality of test points exposed at the major surface thereof and distributed about an electronic component in a pattern that corresponds to the pattern of contact pads on the first main face of the flexible sheet, the contact pads can be brought into contact with the test points respectively,

3. A probe according to claim 1, wherein the conductor run extends over said first main face of the sheet of dielectric material, and the probe further comprises a second flexible sheet of dielectric material covering the conductor run.

4. A probe according to claim 1, wherein the conductor extends over the second main face of the sheet of dielectric material.

5. A probe according to claim 1, wherein the sheet of dielectric material is transparent.

6. A method of testing a populated circuit board that comprises a support member having a major surface, and an electronic component mounted on the support member at the major surface thereof and having a top surface spaced from the major surface of the support member, the circuit board having a test point adjacent said component, the test point having a top surface that is closer to the major surface of the circuit board than is the top surface of the electronic component, the method comprising:

providing a probe comprising a flexible sheet of dielectric material having an opening extending therethrough and sized and shaped to receive the electronic component, a contact pad exposed at a first main face of the sheet and adjacent the opening therein, and a conductor run adhered to the flexible sheet and connecting the contact pad to a terminal of the probe,

positioning the probe with the first main face of the flexible sheet in confronting relationship with the major surface of the support member and with the opening in the sheet in registration with the electronic component, and

applying pressure to a second main face of the flexible sheet, opposite the first main face thereof, whereby the contact pad is brought into contact with the test point.

7. In combination:

a populated circuit board comprising a support member having a major surface and an electronic component mounted on the support member at the major surface thereof, the circuit board having a plurality of test points exposed at the major surface at predetermined positions relative to said component, and

apparatus for testing the circuit board, the apparatus comprising;

a probe comprising a flexible sheet of dielectric material having first and second main faces and formed with an opening extending therethrough and sized and shaped to receive the electronic component, contact pads exposed at the first main face of the sheet at positions relative to the opening corresponding to the positions of the test points relative to the electronic component, and conductor runs adhered to the flexible sheet and connecting the contact pads to probe terminals,

means for applying pressure to the probe when the probe is positioned with the first surface of the sheet in confronting relationship with the circuit board and the opening in the sheet is in registration with the electronic component, whereby the contact pads are brought into contact with the test points respectively, and

a test instrument connected to the terminals of the probe for observing electrical signals transmitted from the test points by the probe.

8. A combination according to claim 7 wherein the conductor runs and adhered to said first main face of the sheet of dielectric material, and the probe further comprises a second flexible sheet of dielectric material covering the conductor runs.