Interconnect assemblies and methods

• US 6,713,374 B2
• Filed: 12/29/2000
• Issued: 03/30/2004
• Est. Priority Date: 07/30/1999
• Status: Expired due to Fees

• Current Assignee: FormFactor Incorporated
• Original Assignee: FormFactor Incorporated
• Inventors: Mathieu, Gaetan, Eldridge, Benjamin N.
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): MALSAWMA, LALRINFAMKIM HMAR
• Application Number:
  US09/752,640
• Publication Number:
  US 20010001080A1
• Time in Patent Office: 1,187 Days
• Field of Search: 438/117, 438/106, 438/611, 438/670, 438/597, 257/735
• US Class Current: 438/611
• CPC Class Codes: H01L 23/4822 Beam leads
• CPC Class Codes: H01L 24/01 Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/12042 LASER
• CPC Class Codes: H01L 2924/14 Integrated circuits

Abstract

An interconnect assembly and methods for making and using the assembly. An exemplary embodiment of an aspect of the invention includes a contact element which includes a base portion adapted to be adhered to a substrate and a beam portion connected to and extending from the base portion. The beam portion is designed to have a geometry which substantially optimizes stress across the beam portion when deflected (e.g. it is triangular in shape) and is adapted to be freestanding. An exemplary embodiment of another aspect of the invention involves a method for forming a contact element. This method includes forming a base portion to adhere to a substrate of an electrical assembly and forming a beam portion connected to the base portion. The beam portion extends from the base portion and is designed to have a geometry which substantially evenly distributes stress across the beam portion when deflected and is adapted to be freestanding. It will be appreciated that in certain embodiments of the invention, a plurality of contact elements are used together to create an interconnect assembly. Various other assemblies and methods are also described below in conjunction with the following figures.

Claims

1. A method of forming a contact element comprising a base portion to adhere to an electronic device and a beam portion connected to said base portion and configured to slope away from said electronic device, said method comprising:

forming a first masking layer comprising a first opening, said first opening comprising a first region corresponding to said base portion and a second region defining said slope of said beam portion;

depositing a conductive material into said first opening;

forming a second masking layer comprising a second opening, wherein said second opening defines a planar shape of said beam portion; and

depositing a contact element material into said second opening.

2. The method of claim 1, wherein said planar shape of said beam portion is substantially triangular.

3. The method of claim 1, wherein said planar shape of said beam portion substantially evenly distributes throughout said beam stress from deflection of said beam.

4. The method of claim 1, wherein said planar shape of said beam portion substantially optimizes a stress parameter given a desired size constraint of said beam portion and a desired spring constant for said contact element.

5. The method of claim 1, wherein said beam portion is configured to slope away from said electronic device at an oblique angle relative to a surface of said electronic device.

6. The method of claim 1, wherein said beam portion comprises a contact portion for contacting a second electronic device, and said beam portion is configured to resiliently deflect upon application of a force to said contact portion.

7. The method of claim 1, wherein said beam portion is further configured to laterally wipe said second electronic device as said second electronic device applies said force to said contact portion.

8. The method of claim 1, said step of depositing a contact element wherein material comprises plating said contact element material into said conductive material.