Probe card configuration for low mechanical flexural strength electrical routing substrates

• US 7,071,715 B2
• Filed: 02/02/2004
• Issued: 07/04/2006
• Est. Priority Date: 01/16/2004
• Status: Expired due to Fees

• Current Assignee: FormFactor Incorporated
• Original Assignee: FormFactor Incorporated
• Inventors: Cooper, Timothy E., Eldridge, Benjamin N., Shenoy, Ravindra V., Shinde, Makarand S., Larder, Richard A.
• Primary Examiner(s): Nguyen, Vinh
• Assistant Examiner(s): Chan, Emily Y
• Application Number:
  US10/771,099
• Publication Number:
  US 20050156611A1
• Time in Patent Office: 883 Days
• Field of Search: 324/754, 324750-765
• US Class Current: 324/756.03
• 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

Abstract

A mechanical support configuration for a probe card of a wafer test system is provided to increase support for a very low flexural strength substrate that supports spring probes. Increased mechanical support is provided by: (1) a frame around the periphery of the substrate having an increased sized horizontal extension over the surface of the substrate; (2) leaf springs with a bend enabling the leaf springs to extend vertically and engage the inner frame closer to the spring probes; (3) an insulating flexible membrane, or load support member machined into the inner frame, to engage the low flexural strength substrate farther away from its edge; (4) a support structure, such as support pins, added to provide support to counteract probe loading near the center of the space transformer substrate; and/or (5) a highly rigid interface tile provided between the probes and a lower flexural strength space transformer substrate.

Claims

1. A probe card assembly for testing a device comprising:

a substrate with probe contacts on a first surface;

a probe card to electrically connect said probe contacts to a test system;

an electrical connection means to connect the probe contacts to the probe card; and

support means positioned against a second surface of the substrate substantially opposite said probe contacts without electrically connecting to the probe contacts, the support means transmitting probe forces introduced when the probe contacts are urged against corresponding contacts on the device being tested; and

a frame provided around a peripheral edge of the substrate, the frame including a horizontal extension extending over the surface of the substrate, wherein the probe forces are transmitted by the support means to the frame, wherein the horizontal extension of the frame includes a load support member extending vertically from a surface of the horizontal extension to engage the first surface of the substrate in an area separated from the peripheral edge of the substrate.

2. A probe card assembly for testing a device comprising:

a substrate with probe contacts on a first surface;

a probe card to electrically connect said probe contacts to a test system;

an electrical connection means to connect the probe contacts to the probe card; and

support means positioned against a second surface of the substrate substantially opposite said probe contacts without electrically connecting to the probe contacts, the support means transmitted probe forces introduced when the probe contacts are urged against corresponding contacts or the device being tested;

a frame provided around a peripheral edge of the substrate, the frame including a horizontal extension extending over the surface of the substrate, wherein the probe forces are transmitted by the support means to the frame;

a first membrane provided between a surface of the horizontal extension of the frame and the first substrate surface; and

a second membrane provided between the first membrane and the substrate to engage the substrate in an area separated from the peripheral edge of the substrate.

3. A probe card assembly for testing a wafer comprising:

a substrate having a surface supporting probe contacts; and

a frame provided around a peripheral edge of the substrate, the frame including a horizontal extension extending over the surface of the substrate supporting the probe contacts, the horizontal extension comprising a load support member extending vertically from a surface of the horizontal extension to engage the surface of the substrate supporting the probe contacts in an area from the peripheral edge of the substrate.

4. The probe card assembly of claim 3, wherein the load support member is machined into the frame.

5. The probe card assembly of claim 3, wherein the load support member comprises flexible membrane.

6. A probe card assembly of claim 5, wherein the flexible membrane comprises:

a first membrane provided between a surface of the horizontal extension of the frame and the substrate surface; and

a second membrane provided between the first membrane and the substrate to engage the surface of the substrate supporting the probe contacts in the area separated from the peripheral edge of the substrate.

7. The probe card assembly of claim 6, wherein the first membrane and the second membrane comprise an electrically insulating material.

8. A probe card assembly of claim 3, wherein the horizontal extension extends over an area comprising 70% or more of the surface of the substrate supporting the probe contacts.

9. A probe card assembly for testing a device comprising:

a first substrate with probe contacts on a first surface, the first substrate comprising a first material;

a second substrate attached to a second surface of the first substrate, the second substrate including routing lines electrically connecting to the probe contacts, the routing lines further providing connections to a test system, the second substrate comprising a second material different than the first material;

a printed circuit board (PCB) having connectors for connecting to a test head on one side, and electrical connections provided on a second side for connecting to the routing lines of a second substrate;

an bracket fixedly connected to the PCB;

a frame provided around a peripheral edge of the second substrate, the frame including a horizontal extension extending over the first surface of the second substrate, wherein the horizontal extension comprises a load support member extending vertically from a surface of the horizontal extension to engage the surface of the second substrate supporting the probe contacts in an area separated from the peripheral edge of the second substrate; and

leaf springs having a first end attached to the bracket, and a second end to engage a surface of the frame.

10. The probe card assembly of claim 9, wherein the load support member is machined the frame.

11. The probe card assembly of claim 9, wherein the load support member comprises a flexible membrane.

12. The probe card assembly of claim 9, wherein the leaf springs include bends between the first end and the second end to enable the peripheral edge of the frame to extend vertically from the bracket.