Anisotropic-electroconductive adhesive composition, method for connecting circuits using the same, and connected circuit structure thus obtained

• US 4,740,657 A
• Filed: 02/12/1987
• Issued: 04/26/1988
• Est. Priority Date: 02/14/1986
• Status: Expired due to Term

• Current Assignee: Hitachi Chemical Company Limited (Resonac Holdings Corp.)
• Original Assignee: Hitachi Chemical Company Limited (Resonac Holdings Corp.)
• Inventors: Muto, Kuniteru, Ikezoe, Yoshiyuki, Yamaguchi, Yutaka, Tsukagoshi, Isao, Nakajima, Atsuo, Mikami, Yoshikatsu
• Primary Examiner(s): NIMMO, MORRIS
• Application Number:
  US07/013,904
• Time in Patent Office: 439 Days
• Field of Search: 174/84 R, 174/88 R, 174/94 R, 29/868, 252/512, 252/513, 252/514
• US Class Current: 174/88.00R
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01L 2224/293 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/29399 Coating material
• CPC Class Codes: H01L 2224/81903 by means of a layer connector
• CPC Class Codes: H01L 2224/83851 being an anisotropic conductive adhesive
• CPC Class Codes: H01L 2224/9211 Parallel connecting processes
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01R 4/04 using electrically conductive adhesives
• CPC Class Codes: H05K 2201/0221 Insulating particles having an electrically conductive coating
• CPC Class Codes: H05K 2201/0233 Deformable particles insulating particles having an electrically conductive coating H05K2201/0221
• CPC Class Codes: H05K 2201/068 wherein the coefficient of thermal expansion is important
• CPC Class Codes: H05K 3/323 by applying an anisotropic conductive adhesive layer over an array of pads
• CPC Class Codes: H05K 3/361 Assembling flexible printed circuits with other printed circuits
• CPC Class Codes: Y10T 29/49194 Assembling elongated conductors, e.g., splicing, etc.

Abstract

Excellent connection of conductors with high reliability can be accomplished by using an adhesive composition or flim capable of exhibiting anisotropic-electroconductivity comprising electroconductive particles comprising polymeric core materials coated with thin metal layers, and electrically insulating adhesive component.

Claims

1. An adhesive composition for connecting conductors and capable of exhibiting anisotropic-electroconductivity by applying pressure or pressure with heating comprising 0.1 to 15% by volume of electroconductive particles and 99.9 to 85% by volume of an electrically insulating adhesive component, each electroconductive particle comprising a polymeric material as a core, material and an electrically conductive thin metallic layer coated on almost the whole surface of said core material.

2. An adhesive composition according to claim 1, wherein the electroconductive particles have an aspect ratio of 0.05 to 1.0 and an average particle size (diameter) of 0.5 to 300 μ

m, and the ratio of the thermal expansion coefficient of the adhesive component to that of the core material being 0.1/1 to 10/1 and the ratio of the modulus of elasticity in tension of the adhesive component to that of the core material being 1.2/1 to 0.01/1.

3. An adhesive composition according to claim 1, wherein the core material has plastic deformation properties under a pressure or a pressure with heating.

4. An adhesive composition according to claim 2, wherein the core material has a thermal expansion coefficient of 20×

10^-5 (1/°

C.) to 2×

10^-5 (1/°

C.).

5. An adhesive composition according to claim 2, wherein the thickness of the metal thin layer is 0.01 to 5 μ

m and 1/5 to 1/1000 of the average particle size diameter of the electroconductive particles.

6. An adhesive composition according to claim 2, wherein the adhesive component has heat-sensitive adhesiveness.

7. An adhesive composition according to claim 2, wherein the adhesive component has pressure-sensitive adhesiveness.

8. An adhesive composition according to claim 2, wherein the adhesive component is at least one material selected from the group consisting of a heat curing type and a photocuring type.

9. An adhesive film for connecting conductors and capable of exhibiting anisotropic-electroconductivity by applying pressure or pressure with heating comprising 0.1 to 15% by volume of electroconductive particles and 99.9 to 85% by volume of an electrically insulating adhesive component, each electroconductive particle comprising a polymeric material as a core material and an electrically conductive this metallic layer coated on almost the whole surface of said core material.

10. An adhesive film according to claim 9, wherein the electroconductive particles have an aspect ratio of 0.05 to 1.0 and an average particle size (diameter) of 0.5 to 300 μ

m, and the ratio of the thermal expansion coefficient of the adhesive component to that of the core material being 0.5/1 to 10/1 and the ratio of the modulus of elasticity in tension of the adhesive component to that of the core material being 1.2/1 to 0.01/1.

11. An adhesive film according to claim 10, wherein the core material has plastic deformation properties under a pressure or a pressure with heating.

12. An adhesive film according to claim 10, wherein the core material has a thermal expansion coefficient of 20×

10^-5 (1/°

C.) to 2×

10^-5 (1/°

C.).

13. An adhesive film according to claim 10, wherein the thickness of the metal thin layer is 0.1 to 1.0 μ

m and 1/5 to 1/1000 of the average particle size diameter of the electroconductive particles.

14. An adhesive film according to claim 10, wherein the adhesive component has heat-sensitive adhesiveness.

15. An adhesive film according to claim 10, wherein the adhesive component has pressure-sensitive adhesiveness.

16. An adhesive film according to claim 10, wherein the adhesive component is at least one material selected from the group consisting of a heat curing type and a photocuring type.

17. A adhesive film according to claim 10, wherein the adhesive film has a thickness of 1 to 300 μ

m.

18. A adhesive film according to claim 10, wherein the adhesive film has a total light transmittance of 40% or more.

19. A method for connecting conductors which comprises

interposing an adhesive composition or an adhesive film capable of exhibiting anisotropic-electro-conductivity by applying pressure or pressure with heating comprising 0.1 to 15% by volume of electroconductive particles, each electroconductive particle comprising a polymeric material as a core material and an electrically conductive thin metallic layer coated on almost the whole surface of said core material, said electroconductive particles being dispersed in 99.9 to 85% by volume of an adhesive component, between electrode conductors standing opposite to each other, and

pressing without heating or pressing with heating said conductors so as to make the thickness of the adhesive layer between the conductors in the range of 0.02 to 0.95 of the initial thickness so as to provide electrical connection and mechanical bonding between the conductors.

20. A method according to claim 19, wherein the electroconductive particles have an aspect ratio of 0.05 to 1.0 and an average particle size (diameter) of 0.5 to 300 μ

m, and a ratio of the thermal expansion coefficient of the adhesive component to that of the core material being 0.5/1 to 10/1 and a ratio of the modulus of elasticity in tension of the adhesive component to that of the core material being 1.2/1 to 0.01/1.

21. A method according to claim 19, wherein a conductor connection portion is crosslinked and cured with heating and/or light irradiation at the time of connection of conductors and/or after connection of conductors.

22. A connected conductor structure comprising conductors standing opposite to each other and connecting materials connecting said conductors electrically, said connecting materials comprising 0.1 to 15% by volume of electroconductive particles and 99.9 to 85% by volume of an electrically insulating adhesive component, each electroconductive particle comprising a polymeric material as a core material and an electrically conductive thin metallic layer coated on almost the whole surface of said core material, and said electroconductive particles being fixed between the conductors standing opposite to each other in a deformed state pressed by the conductors.

23. A connected conductor structure according to claim 22, wherein the electroconductive particles have an aspect ratio of 0.05 to 1.0 and an average particle size (diameter) of 0.5 to 300 μ

m, and a ratio of the thermal expansion coefficient of the adhesive component to that of the core material being 0.5/1 to 10/1 and a ratio of the modulus of elasticity in tension of the adhesive component to that of the core material being 1.2/1 to 0.01/1.

24. A connected conductor structure according to claim 22, wherein at least one conductor standing opposite to each other is a transparent electroconductive film.

25. A connected conductor structure according to claim 22, wherein said connecting material further comprises highly rigid spacer particles which can control the distance between the conductors to be connected.