Electrical interconnection means

• US 4,640,981 A
• Filed: 08/14/1985
• Issued: 02/03/1987
• Est. Priority Date: 10/04/1984
• Status: Expired due to Term

• Current Assignee: AMP Incorporated (Johnson Controls International plc)
• Original Assignee: AMP Incorporated (Johnson Controls International plc)
• Inventors: Jones, Warren C., Dery, Ronald A.
• Primary Examiner(s): Grimley, Arthur T.
• Assistant Examiner(s): Nimmo, Morris H.
• Application Number:
  US06/765,625
• Time in Patent Office: 538 Days
• Field of Search: 174/88 R, 174/117 A, 174/117 PC, 174/117 FF, 174/71 R, 174/72 C, 361/398, 361/411, 156/47, 156/51, 156/52, 29/830, 29/832, 29/846
• US Class Current: 174/88.00R
• CPC Class Codes: H01R 12/61 connecting to flexible printed circuits, flat or ribbon cables or like structures
• CPC Class Codes: H01R 4/04 using electrically conductive adhesives
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder
• CPC Class Codes: H05K 2201/0272 Mixed conductive particles, i.e. using different conductive particles, e.g. differing in shape
• CPC Class Codes: H05K 2201/10727 Leadless chip carrier [LCC], e.g. chip-modules for cards
• CPC Class Codes: H05K 2201/10977 Encapsulated connections
• CPC Class Codes: H05K 2203/0278 Flat pressure, e.g. for connecting terminals with anisotropic conductive adhesive
• CPC Class Codes: H05K 2203/1189 Pressing leads, bumps or a die through an insulating layer
• CPC Class Codes: H05K 2203/1453 Applying the circuit pattern before another process, e.g. before filling of vias with conductive paste, before making printed resistors
• CPC Class Codes: H05K 3/305 Affixing by adhesive
• CPC Class Codes: H05K 3/321 by conductive adhesives
• CPC Class Codes: H05K 3/361 Assembling flexible printed circuits with other printed circuits

Abstract

An interconnecting means is comprised of one or more conductive ink conductors screen printed onto a first substrate, the conductive ink being comprised of an insulating polymer medium having first and second groups of conductive particles therein, and an insulating layer of flowable adhesive in covering relationship to the conductors. The first group of particles are finely divided particles which are suspended in the medium and form a continuous conductive path along the length of the conductor. The second group of particles are agglomerates of large particles which are randomly scattered throughout the conductive path and project above the surface of the medium. Interconnection is effected by positioning the first substrate conductors in an overlapping conducting relationship to the conductors on the second substrate such that the flowable adhesive is deposited between the two substrates and applying pressure to the positioned conductors and surrounding areas. The adhesive flows from the positioned areas, exposes the protruding agglomerates, thus bringing the agglomerates into contact and electrical interconnection with the second substrate conductors accompanied by the adhesion of the remaining first substrate surface to the surface of the second substrate.

Claims

1. An electrical interconnection means of the type comprising a first insulating substrate having a plurality of conductors on one surface thereof and having an insulating adhesive in covering relationship to the conductors, the adhesive being flowable under pressure, the interconnecting means being characterized in that:

the conductors are of conductive ink comprising an insulating polymer medium having first and second groups of conductive particles therein,

the first group of particles are finely divided particles which are suspended in the medium and form a continuous conductive path along the length of each conductor,

the second group of particles are agglomerates of large size particles which are randomly scattered throughout the conductive path and project above the surface of the medium, and

the flowable adhesive extends over the surface of the insulating substrate, conductors, and projecting agglomerates to provide insulation whereby

upon locating and positioning the first insulating substrate conductors in an overlapping conducting relationship to conductors on a second substrate such that the flowable adhesive is disposed between the two substrates and applying pressure to the positioned conductors and surrounding area, the adhesive flows from the positioned areas and exposes the protruding agglomerates thus bringing the exposed agglomerates into contact and electrical interconnection with the conductors on the second substrate accompanied by the adhesion of the remaining first substrate surface to the surface of the second substrate.

2. An electrical interconnection means as recited in claim 1 wherein the flowable adhesive is a thermoplastic flowable adhesive which will flow when heat and pressure are applied.

3. An electrical interconnecting means as recited in claim 1 wherein the first substrate is flexible.

4. An electrical interconnecting means as recited in claim 1 wherein the first substrate is rigid.

5. An electrical interconnecting means as recited in claim 1 wherein the finely divided particles have a major axis of approximately 15 micrometers and a minor axis of approximately 3 micrometers and the large size particles are essentially spheroidal and have a diameter ranging from 15 to 90 micrometers.

6. An electrical interconnecting means comprising:

a first insulating member having at least one first conductive path means thereon, said first conductive path means in the form of a conductive ink including an insulating medium having a first group of finely divided conductive particles uniformly suspended and dispersed throughout said insulating medium and a second group of large size conductive particles randomly scattered throughout said insulating medium, some of the large size conductive particles projecting outwardly from said insulating medium;

an insulating adhesive layer secured onto said first insulating member covering said at least one first conductive path means thereon;

a second insulating member having at least one second conductive path means thereon;

said at least one first conductive path means is positioned in conducting relationship to said at least one second conductive path means, such that the adhesive layer is disposed between said first and second insulating members, and said first and second conductive path means; and

said large conductive particles on said at least one first conductive path means extend through said insulating adhesive layer and make electrical connection with said at least one second conductive path means.

7. An electrical interconnection means as defined in claim 6, wherein said adhesive in said adhesive layer is a pressure sensitive adhesive which will flow when pressure is applied.

8. An electrical interconnection means as defined in claim 6, wherein said adhesive in said adhesive layer is thermoplastic flowable adhesive which will flow when heat and pressure are applied.

9. An insulating substrate comprising:

an insulating member having at least one conductive path means thereon, said conductive path means in the form of a conductive ink including an insulating medium having a first group of finely divided conductive particles uniformly suspended and dispersed throughout said insulating medium and a second group of large size conductive particles randomly scattered throughout said insulating medium, some of the large size conductive particles projecting outwardly from said insulating medium, and

an insulating layer secured onto the insulating member covering the conductive path means.

10. An insulating substrate as recited in claim 9 wherein said insulating layer is a thermoplastic flowable adhesive which will flow when heat and pressure are applied.

11. An insulating substrate as recited in claim 9 wherein said insulating layer is a pressure sensitive adhesive which will flow when pressure is applied.

12. An insulating substrate as recited in claim 9 wherein the substrate is selected from the group comprised of flexible, semiflexible and rigid substrates.

13. An insulating substrate as recited in claim 9 wherein the finely divided particles have a major axis of approximately 15 micrometers and a minor axis of approximately 3 micrometers and the large size particles are essentially spheroidal and have a diameter ranging from 15 to 90 micrometers.

14. An insulating substrate as recited in claim 9 further comprising an electrical component having at least one conductive pad member thereon mounted to said insulating substrate with said at least one conductive pad electrically connected to said at least one conductive path means, said at least one conductive pad being positioned in conducting relationship to said at least one conductive path means such that the adhesive layer is between said pad member and said path means;

and said large conductive particles on said at least one conductive path means extend through said adhesive layer and make electrical connection with said at least one conductive pad member.

15. An insulating substrate as defined in claim 14 wherein said adhesive in said adhesive layer is a pressure sensitive adhesive which will flow when pressure is applied.

16. An insulating substrate as defined in claim 14 wherein said adhesive in said adhesive layer is thermoplastic flowable adhesive which will flow when heat and pressure are applied.

17. An adhesive electrical interconnection cable comprised of:

an insulating continuous flexible strip having at least one conductive path means thereon, said conductive path means being in the form of a conductive ink including an insulating medium having a first group of finely divided conductive particles uniformly suspended and dispersed throughout said insulating medium and a second group of large size conductive particles randomly scattered throughout said insulating medium, some of the large size conductive particles, projecting outwardly from said insulating medium, and

an insulating thermoplastic flowable adhesive layer secured onto said flexible strip and covering said conductive path means.

18. An adhesive electrical interconnecting cable comprised of:

an insulating continuous flexible strip having at least one conductive path means thereon, said conductive path means being in the form of a conductive ink including an insulating medium having a first group of finely divided conductive particles uniformly suspended and dispersed throughout said insulating medium and a second group of large size conductive particles randomly scattered throughout said insulating medium, some of the large size conductive particles, projecting outwardly from said insulating medium, and

an insulating pressure sensitive flowable adhesive layer secured onto said flexible strip and covering said conductive path means.

19. An interconnection means made in accordance with the method comprised of the steps of:

selecting a first insulating member;

applying at least one conductive path to said first insulating member, said conductive path being in the form of a conductive ink including an insulating medium having a first group of finely divided conductive particles uniformly suspended and dispersed throughout said insulating medium and a second group of large size conductive particles randomly scattered throughout said insulating medium, some of said large size conductive particles projecting outwardly from said insulating member;

applying an insulating pressure sensitive adhesive layer secured onto said first insulating member covering said at least one conductive path;

positioning said at least one conductive path in a conducting relationship with at least one conductive means on a second insulating member such that said pressure sensitive adhesive layer is disposed between said at least one conductive path and said at least one conductive means;

applying pressure to the positioned at least one conductive path and at least one conductive means causing said pressure sensitive adhesive to flow and become thinner thus causing said large conductive particles on said at least one conductive path to extend through said pressure sensitive adhesive layer and make electrical connection with said at least one conductive means.

20. An electrical interconnection means as recited in claim 19 wherein said second insulating member is a leadless electrical component having at least one conductive pad thereon.