Composite polymer-metal electrical contacts

• US 9,277,654 B2
• Filed: 05/27/2010
• Issued: 03/01/2016
• Est. Priority Date: 06/02/2009
• Status: Active Grant

• Current Assignee: LCP Medical Technologies Incorporated
• Original Assignee: HSIO Technologies LLC
• Inventors: Rathburn, James
• Primary Examiner(s): Nguyen, Chau N
• Assistant Examiner(s): VARGHESE, ROSHN K
• Application Number:
  US13/318,369
• Publication Number:
  US 20120043119A1
• Time in Patent Office: 2,105 Days
• Field of Search: 174/255, 174/260, 174/261, 174/267
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/0554 External layer
• CPC Class Codes: H01L 2224/0555 Shape
• CPC Class Codes: H01L 2224/0556 Disposition
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 23/49811 Additional leads joined to the metallisation on the insulating substrate, e.g. pins, bumps, wires, flat leads H01L23/49827 takes precedence
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/12044 OLED
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01R 12/52 connecting to other rigid printed circuits or like structures
• CPC Class Codes: H05K 2201/0133 Elastomeric or compliant polymer
• CPC Class Codes: H05K 2201/0311 Metallic part with specific elastic properties, e.g. bent piece of metal as electrical contact
• CPC Class Codes: H05K 3/325 by abutting or pinching, i.e. without alloying process; mechanical auxiliary parts therefor adaptations of leads inserted in holes for press-fit connections H05K3/308
• CPC Class Codes: Y10T 29/49224 with coating

Abstract

An array of composite polymer-metal contact members adapted to form solder free electrical connections with a first circuit member. The contact members include a resilient polymeric base layer and an array of metalized traces printed on selected portions of the base layer. Conductive plating is applied to the metalized layer to create an array of conductive paths. The resilient polymeric base layer, the metalized layer, and the conductive plating have an aggregate spring constant sufficient to maintain distal portions of the contact members in a cantilevered configuration and to form a stable electrical connection between the distal portions and the first circuit member solely by compressive engagement.

Claims

1. An array of composite polymer-metal contact members forming solder free electrical connections with a first circuit member, the contact members comprising:

a resilient base layer comprising a continuous sheet of a liquid crystal polymer;

at least one polymeric dielectric layer selectively positioned on the polymeric base to form recesses corresponding to a desired circuit trace;

a conductive material deposited in at least a portion of the recesses comprising conductive traces surrounded on at least one side by the resilient base layer and on at least two sides by the polymeric dielectric layer, the conductive traces comprising exposed terminals that electrically couple to the first circuit member; and

the resilient polymeric base layer, the dielectric material, and the conductive traces comprising an aggregate spring constant maintaining distal portions of the contact members in a cantilevered configuration that flexes to form a stable, solder free electrical connection between the distal portions and the first circuit member solely by compressive engagement.

2. The contact members of claim 1 comprising a mechanically stable metalized portion printed on proximal portions of the contact members, the metalized portion adapted to bond to a second circuit member.

3. The contact members of claim 1 comprising:

a metalized portion at proximal ends of the contact members; and

a solder balls bonded to the metalized portions.

4. The contact members of claim 1 comprising a housing coupled to proximal portions of the contact members, wherein the distal portions flex relative to the housing during compressive engagement with the first circuit member.

5. The contact members of claim 1 wherein a proximal portion of the polymeric base layer is bonded to a second circuit member so the distal portions of the contact members are maintained in a cantilevered relationship to the second circuit member.

6. The contact members of claim 1 wherein proximal portions of the conductive paths are bonded to contact pads on a second circuit member so the distal portions of the contact members are maintained in a cantilevered relationship to the second circuit member.

7. The contact members of claim 1 comprising a plurality of electrical devices printed on the polymeric base layer and electrically coupled to at, least one of the conductive paths.

8. The contact members of claim 1 wherein conductive traces comprise substantially rectangular cross-sectional shapes.

9. An electrical assembly comprising proximal portions of the contact members of claim 1 bonded to contact pads on a second circuit member and distal portions of the contact members compressively coupled to contact pads on the first circuit member.

10. The electrical assembly of claim 9 wherein the first and second circuit members are selected from one of a dielectric layer, a printed circuit board. a flexible circuit, a bare die device, an integrated circuit device, organic or inorganic substrates, or a rigid, circuit.

11. A method that forms an array of composite polymer-metal contact members forming a solder free electrical connections with a first circuit member, the method comprising:

selectively printing at least one polymeric dielectric layer on a polymeric base layer comprising a continuous sheet of a liquid crystal polymer to form recesses corresponding to the array of metalized traces;

printing a conductive material in at least a portion of the recesses;

plating an array of conductive paths on the array of metalized traces surrounded on at least one side by the polymeric base layer and on at least two sides by the polymeric dielectric layer, the resilient polymeric base layer, the metalized layer, and the conductive plating comprising an aggregate spring constant maintaining distal portions of the contact members in a cantilevered configuration;

securing proximal portions of the contact members; and

forming a stable electrical connection between the distal portions of the contact members and the first circuit member solely by flexing the contact member in response to compressive engagement.

12. The method of claim 11 comprising the steps of

printing mechanically stable metalized portions at proximal portions of the contact members;

and

bonding the metalized portions to contact pads on a second circuit member.

13. The method of claim 11 comprising:

printing metalized portions at proximal ends of the contact members; and

bonding solder balls to the metalized portions.

14. The method of claim 11 comprising coupling proximal portions of the contact members to a housing, wherein the distal portions of the contact members flex relative to the housing during compressive engagement with the first circuit member.

15. The method of claim 11 comprising bonding a proximal portion of the polymeric base layer to a second circuit member so the distal portions are maintained in a cantilevered relationship to the second circuit member.

16. The method, of claim 11 comprising bonding proximal portions of the conductive paths to contact pads on a second circuit member so the distal portions are maintained in a cantilevered relationship to the second circuit member.

17. The method of claim 11 comprising printing a plurality of electrical devices on the polymeric base layer and electrically coupling the electrical devices to at least one of the conductive paths.

18. The method of claim 11 comprising forming the polymeric base layer into a non-planar shape.

19. A method of forming an electrical assembly comprising the steps of:

bonding proximal portions of the contact members of claim 11 to contact pads on a second circuit member; and

compressively coupling distal portions of the contact members to contact pads on the first circuit member.