Probe card configuration for low mechanical flexural strength electrical routing substrates

• US 20060244470A1
• Filed: 06/30/2006
• Published: 11/02/2006
• Est. Priority Date: 01/16/2004
• Status: Active Grant

• Current Assignee: FormFactor Incorporated
• Original Assignee: FormFactor Incorporated
• Inventors: Cooper, Timothy E., Eldridge, Benjamin N., Shenoy, Ravindra V., Shinde, Makarand S., Larder, Richard A.
• Granted Patent: US 7,825,674 B2
• Time in Patent Office: Days
• US Class Current: 324/756.30
• 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

1-49. -49. (canceled)

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

a substrate with probe contacts on a first surface, the probe contacts being provided in a defined area of the substrate;

electrical contacts provided on a second surface of the substrate, the electrical contacts being electrically connected through the substrate to the probes;

an interface to electrically connect the electrical contacts to a test system; and

support means positioned against a second surface of the substrate, wherein the support means contacts the second side of the substrate within the defined area 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.

51. The probe card assembly of claim 50, wherein the substrate comprises a ceramic material.

52. The probe card assembly of claim 50, wherein the substrate comprises an organic material.

53. The probe card assembly of claim 50, wherein the support means comprises a screw element.

54. The probe card assembly of claim 50, wherein the support means comprises an elastomer pad.

55. The probe card assembly of claim 50, wherein the support means comprises a gimble.

56. The probe card assembly of claim 50, wherein the support means comprises a rigid support member attached to the substrate.

57. The probe card assembly of claim 50, wherein the support means comprises a gimble removably contacting a rigid support member attached to the substrate.

58. The probe card assembly of claim 50, further comprising:

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.

59. The probe card assembly of claim 58, wherein the interface comprises:

a printed circuit board (PCB) having connectors to connect with a test head on a first side, and electrical connection pads on an opposing second side for connecting to the electrical contacts, the probe card assembly further comprising;

a bracket fixedly attached to the second side of the PCB, the bracket being provided around the peripheral edge of the frame; and

leaf springs having a first end attached to the bracket, and a second end contacting the frame so that the force applied by the leaf springs and support means support the substrate within the frame.

60. The probe card assembly of claim 57, wherein the interface comprises:

a printed circuit board (PCB) having connectors to connect to the test head on a first side, and electrical connection pads on an opposing side, the PCB including an opening through which the screw element passes; and

an interposer having electrically conductive spring contacts on each side to connect the pads of the PCB to the electrical contacts on the second surface of the substrate, the interposer including an opening through which the screw element passes.

61. The probe card assembly of claim 50, wherein the substrate comprises:

a first substrate layer having probe contacts on a first surface, the first substrate comprising a first material; and

a second substrate attached to a second surface of the first substrate, the second substrate including routing lines electrically connecting the probe contacts, the routing lines further providing connections to connect to the probe card, the second substrate comprising a second material having a lower flexural strength than the first material.

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

a substrate with an array of probe contacts on a first surface;

electrical contacts provided on a second surface of the substrate, the electrical contacts being electrically connected through the substrate to the probes; and

support means positioned against a second surface of the substrate 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.

63. The probe card assembly of claim 62, wherein the support means comprises a screw element.

64. The probe card assembly of claim 62, wherein the support means comprises an elastomer pad.

65. The probe card assembly of claim 62, wherein the support means comprises a gimble.

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

a substrate with probe contacts on a first surface;

electrical contacts provided on a second surface of the substrate, the electrical contacts being electrically connected through the substrate to the probes; and

support pins positioned against a second surface of the substrate opposite said probe contacts and separated from said electrical contacts, the support pins transmitting probe forces introduced when the probe contacts are urged against corresponding contacts on the device being tested.

67. The probe card assembly of claim 66, wherein the support pins include an elastomer pad tip that contacts the substrate.

68. The probe card assembly of claim 66, wherein the support pins comprise a rigid support member attached to the substrate.

69. The probe card assembly of claim 66, wherein the support pins connect to gimbles attached to the substrate.