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

• US 9,099,449 B2
• Filed: 01/08/2015
• Issued: 08/04/2015
• Est. Priority Date: 11/04/2010
• Status: Expired due to Fees

• Current Assignee: FormFactor Beaverton, Inc. (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:
  US14/592,749
• Publication Number:
  US 20150114925A1
• Time in Patent Office: 208 Days
• Field of Search: 324/754, 324/755, 439/65, 439/66, 439/591, 439/862, 295/93, 298/37, 298/40, 298/50
• US Class Current: 1/1
• 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. A method of forming an electrical interposer including a resilient dielectric body that includes an elastomeric layer, the method comprising:

forming a plurality of interposer conduits on a surface of a substrate;

forming the elastomeric layer on a carrier surface, wherein the elastomeric layer includes an exposed surface;

pressing the exposed surface of the elastomeric layer and the surface of the substrate into contact with one another;

embedding the plurality of interposer conduits in the elastomeric layer, wherein the embedding includes mechanically contacting at least a portion of each of the plurality of interposer conduits with the carrier surface;

separating the carrier surface from the elastomeric layer; and

separating the surface of the substrate from the elastomeric layer while leaving the plurality of interposer conduits embedded within the elastomeric layer.

2. The method of claim 1, wherein, prior to the pressing, the method includes applying an adhesive layer to at least one of the surface of the substrate, the plurality of interposer conduits, and the exposed surface of the elastomeric layer.

3. The method of claim 1, wherein forming the elastomeric layer includes curing the elastomeric layer.

4. The method of claim 3, wherein the curing includes curing the elastomeric layer prior to the pressing.

5. The method of claim 3, wherein the curing includes curing the elastomeric layer subsequent to the pressing.

6. The method of claim 5, wherein the curing includes forming an adhesive bond between the elastomeric layer and the plurality of interposer conduits.

7. The method of claim 1, wherein the forming the elastomeric layer includes at least one of applying the elastomeric layer to the carrier surface and casting the elastomeric layer on the carrier surface.

8. The method of claim 1, wherein the embedding includes forming an adhesive bond between the plurality of interposer conduits and the elastomeric layer.

9. The method of claim 1, wherein forming the plurality of interposer conduits includes performing at least one of a deposition process, a lithography process, an etch process, and a mechanical dimpling process.

10. The method of claim 1, wherein the separating the carrier surface from the elastomeric layer includes at least one of etching the carrier surface and dissolving the carrier surface.

11. The method of claim 1, wherein the separating the surface of the substrate from the elastomeric layer includes at least one of etching the substrate and dissolving the substrate.

12. The method of claim 1, wherein the plurality of interposer conduits includes a plurality of rocking beam electrical conduits, wherein the plurality of rocking beam electrical conduits includes a plurality of beam structures, wherein a first end of each of the plurality of beam structures includes a tip that extends from the beam structure and is configured to contact a device under test, and further wherein an opposed second end of each of the plurality of beam structures includes a beam contact that extends from the beam structure.

13. The method of claim 12, wherein the forming the plurality of interposer conduits includes polishing the beam structure to a desired thickness and polishing the beam contact to a desired length to produce a desired thickness for the elastomeric layer subsequent to the pressing and the embedding.

14. The method of claim 12, wherein the forming the plurality of interposer conduits includes polishing the beam structure to a desired planarity to produce a desired planarity of the elastomeric layer subsequent to the pressing and the embedding.

15. The method of claim 1, wherein the method further includes forming a dimensional stability layer at least one of within the electrical interposer and on a surface of the electrical interposer, wherein the dimensional stability layer is configured to maintain a relative orientation of the plurality of interposer conduits.

16. The method of claim 15, wherein the dimensional stability layer includes a polyimide layer.

17. The method of claim 15, wherein the forming the dimensional stability layer includes forming the dimensional stability layer prior to the separating.

18. The method of claim 15, wherein the forming the dimensional stability layer includes forming the dimensional stability layer subsequent to the separating.

19. The method of claim 1, wherein the substrate includes at least one of a crystalline substrate, a semiconductor substrate, a silicon substrate, a glass substrate, a metallic substrate, and a copper substrate.

20. The method of claim 1, wherein the forming the plurality of interposer conduits includes polishing the plurality of interposer conduits to a desired thickness to produce a desired thickness for the elastomeric layer subsequent to the pressing and the embedding.

21. A method of forming an electrical interposer including a resilient dielectric body that includes an elastomeric layer, the method comprising:

forming a plurality of interposer conduits on a surface of a substrate;

applying the elastomeric layer to the surface of the substrate, wherein the applying includes covering the plurality of interposer conduits with the elastomeric layer, and further wherein the elastomeric layer includes an exposed surface;

pressing a carrier surface and the exposed surface into contact with one another, wherein the pressing includes mechanically contacting the carrier surface with at least a portion of each of the plurality of interposer conduits;

curing the elastomeric layer;

separating the carrier surface from the elastomeric layer; and

separating the surface of the substrate from the elastomeric layer while leaving the plurality of interposer conduits embedded within the elastomeric layer.

22. The method of claim 21, wherein, prior to applying the elastomeric layer, the method includes applying an adhesive layer to at least one of the surface of the substrate and the plurality of interposer conduits.

23. The method of claim 21, wherein curing the elastomeric layer includes forming an adhesive bond between the plurality of interposer conduits and the elastomeric layer.