Resilient electrical interposers, systems that include the interposers, and methods for using and forming the same

• US 8,970,240 B2
• Filed: 11/02/2011
• Issued: 03/03/2015
• Est. Priority Date: 11/04/2010
• Status: Active Grant

• Current Assignee: FormFactor Incorporated
• Original Assignee: Cascade Microtech Incorporated (FormFactor Incorporated)
• Inventors: Smith, Kenneth R., Jolley, Mike, Strid, Eric, Hanaway, Peter, Gleason, K. Reed, Duckworth, Koby L.
• Primary Examiner(s): Vazquez, Arleen M
• Assistant Examiner(s): SHAH, NEEL D
• Application Number:
  US13/287,794
• Publication Number:
  US 20120112779A1
• Time in Patent Office: 1,217 Days
• Field of Search: 324/754, 324/755.01, 324/756, 324/755.09, 324/762.05, 324/754.03, 257/778, 257/781
• US Class Current: 324/755.01
• CPC Class Codes: G01R 1/06727 Cantilever beams
• CPC Class Codes: G01R 1/06733 Geometry aspects G01R1/06727 takes precedence
• CPC Class Codes: G01R 1/07342 the body of the probe being at an angle other than perpendicular to test object, e.g. probe card
• CPC Class Codes: G01R 1/0735 arranged on a flexible frame or film
• CPC Class Codes: H01L 21/4825 Connection or disconnection of other leads to or from flat leads, e.g. wires, bumps, other flat leads
• CPC Class Codes: H01L 21/4828 Etching etching for cleaning without patterning H01L21/4835
• CPC Class Codes: H01L 21/4842 Mechanical treatment, e.g. punching, cutting, deforming, cold welding
• CPC Class Codes: H01L 21/4853 Connection or disconnection of other leads to or from a metallisation, e.g. pins, wires, bumps
• CPC Class Codes: H01L 21/4857 Multilayer substrates multilayer metallisation on monolayer substrate H01L21/4846
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

Resilient electrical interposers that may be utilized to form a plurality of electrical connections between a first device and a second device, as well as systems that may utilize the resilient electrical interposers and methods of use and/or fabrication thereof. The resilient electrical interposers may include a resilient dielectric body with a plurality of electrical conduits contained therein. The plurality of electrical conduits may be configured to provide a plurality of electrical connections between a first surface of the electrical interposer and/or the resilient dielectric body and a second, opposed, surface of the electrical interposer and/or the resilient dielectric body. The systems and methods disclosed herein may provide for improved vertical compliance, improved contact force control, and/or improved dimensional stability of the resilient electrical interposers.

Claims

1. An electrical interposer, comprising:

a resilient dielectric body, wherein the resilient dielectric body includes a first surface and an opposed second surface;

a plurality of rocking beam electrical conduits located within the resilient dielectric body and configured to provide a plurality of electrical connections between a first device that is proximal to the first surface and a second device that is proximal to the second surface, wherein each of the plurality of rocking beam electrical conduits includes a beam structure that is at least substantially parallel to at least one of the first surface and the second surface when the resilient dielectric body is in an undeformed configuration, wherein each of the plurality of rocking beam electrical conduits further includes a probe tip that extends from a first end of the beam structure and is configured to electrically contact the first device, wherein each of the plurality of rocking beam electrical conduits further includes a beam contact that extends from an opposed second end of the beam structure and is configured to electrically contact the second device, wherein the beam contact extends between the beam structure and the second surface, wherein each of the plurality of rocking beam electrical conduits is configured to deflect upon application of a contact force by at least one of the first device and the second device, and further wherein at least a portion of a restoring force for the plurality of rocking beam electrical conduits is provided by the resilient dielectric body; and

a plurality of compliance modifying structures that includes a plurality of compliance modifying regions that is defined within the resilient dielectric body and that includes a different composition than a remainder of the resilient dielectric body, wherein the plurality of compliance modifying regions is configured to change the portion of the restoring force that is provided to the plurality of rocking beam electrical conduits by the resilient dielectric body, and further wherein each of the plurality of compliance modifying regions is directly adjacent to a respective beam structure and extends from only one of the first surface and the second surface.

2. The electrical interposer of claim 1, wherein the plurality of compliance modifying regions includes a plurality of voids within the resilient dielectric body.

3. The electrical interposer of claim 1, wherein the plurality of compliance modifying regions at least one of is not uniformly distributed within the resilient dielectric body, is not uniform in a direction that is parallel to at least one of the first surface and the second surface, is systematically distributed within the resilient dielectric body, separates at least a portion of the plurality of rocking beam electrical conduits from the resilient dielectric body, and extends in a direction that is at least substantially perpendicular to at least one of the first surface and the second surface.

4. The electrical interposer of claim 1, wherein the probe tip extends from the beam structure in a first direction, and further wherein the beam contact extends from the beam structure in a second direction that is generally opposed to the first direction.

5. The electrical interposer of claim 4, wherein the plurality of compliance modifying regions is at least one of associated with, proximal to, and in mechanical communication with the beam contact, and further wherein the plurality of compliance modifying regions is configured to at least one of change, decrease, and increase a scrubbing motion of the probe tip when the probe tip contacts the first device.

6. The electrical interposer of claim 1, wherein the plurality of compliance modifying structures includes a non-circular beam contact cross-section that is configured to increase a distance between a central axis of the beam contact and a central axis of the probe tip for a given beam length.

7. The electrical interposer of claim 1, wherein the resilient dielectric body includes at least one of an elastomer and silicone.

8. The electrical interposer of claim 1, wherein the resilient dielectric body includes at least one of a foam and a closed-cell foam.

9. The electrical interposer of claim 1, wherein at least one of the first device and the second device includes at least one of a space transformer, an electronic device, a device under test, an integrated circuit, an electrical interposer, a socket, a tier of a three-dimensional integrated circuit, a probe head, a portion of a probe head, a probe system, and a portion of a probe system.

10. A layered interposer including a first outer surface and an opposed second outer surface, the layered interposer comprising:

a first electrical interposer, wherein the first electrical interposer includes the electrical interposer of claim 1; and

a second electrical interposer, wherein the second electrical interposer includes the electrical interposer of claim 1, wherein a first surface of the first electrical interposer forms the first outer surface of the layered interposer, wherein a second surface of the first electrical interposer is proximal to and in electrical communication with a first surface of the second electrical interposer, wherein a second surface of the second electrical interposer forms the second outer surface of the layered interposer, and further wherein at least a portion of the plurality of rocking beam electrical conduits of the first electrical interposer is in electrical communication with a respective portion of the plurality of rocking beam electrical conduits of the second electrical interposer and configured to provide the plurality of electrical connections between the first outer surface and the second outer surface.

11. The layered interposer of claim 10, wherein the layered interposer further includes at least a first intermediate interposer between the first interposer and the second interposer.

12. The layered interposer of claim 10, wherein the layered interposer further includes a gap between the resilient dielectric body of the first electrical interposer and the resilient dielectric body of the second electrical interposer, wherein the gap includes at least one of an air gap and a filled gap that includes a dielectric material that is configured to be compressed between the resilient dielectric body of the first electrical interposer and the resilient dielectric body of the second electrical interposer.

13. The electrical interposer of claim 1, wherein the plurality of compliance modifying regions includes a plurality of foam domains within the resilient dielectric body.

14. The electrical interposer of claim 1, wherein the different composition includes at least one of:

(i) a different chemical composition than that of the remainder of the resilient dielectric body;

(ii) a different viscoelasticity than that of the remainder of the resilient dielectric body;

(iii) a different density than that of the remainder of the resilient dielectric body;

(iv) a different Young'"'"'s modulus than that of the remainder of the resilient dielectric body; and

(v) a different yield strain than that of the remainder of the resilient dielectric body.

15. An electrical interposer, comprising:

a resilient dielectric body, wherein the resilient dielectric body includes a first surface and an opposed second surface;

a plurality of rocking beam electrical conduits located within the resilient dielectric body and configured to provide a plurality of electrical connections between a first device that is proximal to the first surface and a second device that is proximal to the second surface, wherein each of the plurality of rocking beam electrical conduits includes a beam structure that is at least substantially parallel to at least one of the first surface and the second surface when the resilient dielectric body is in an undeformed configuration, wherein each of the plurality of rocking beam electrical conduits further includes a probe tip that extends from a first end of the beam structure and is configured to electrically contact the first device, wherein each of the plurality of rocking beam electrical conduits further includes a beam contact that extends from an opposed second end of the beam structure and is configured to electrically contact the second device, wherein the beam contact extends between the beam structure and the second surface, wherein each of the plurality of rocking beam electrical conduits is configured to deflect upon application of a contact force by at least one of the first device and the second device, and further wherein at least a portion of a restoring force for the plurality of rocking beam electrical conduits is provided by the resilient dielectric body; and

a plurality of compliance modifying regions, wherein the plurality of compliance modifying regions is configured to change the portion of the restoring force that is provided to the plurality of rocking beam electrical conduits by the resilient dielectric body, wherein the plurality of compliance modifying regions is defined within the resilient dielectric body and includes a different composition than a remainder of the resilient dielectric body, and further wherein each of the plurality of compliance modifying regions is directly adjacent to a respective first end of a respective beam structure.

16. The electrical interposer of claim 15, wherein the plurality of compliance modifying regions includes a plurality of voids within the resilient dielectric body.

17. The electrical interposer of claim 15, wherein the plurality of compliance modifying regions includes a plurality of foam domains within the resilient dielectric body.

18. The electrical interposer of claim 15, wherein the different composition includes at least one of:

(i) a different chemical composition than that of the remainder of the resilient dielectric body;

(ii) a different viscoelasticity than that of the remainder of the resilient dielectric body;

(iii) a different density than that of the remainder of the resilient dielectric body;

(iv) a different Young'"'"'s modulus than that of the remainder of the resilient dielectric body; and

(v) a different yield strain than that of the remainder of the resilient dielectric body.