Anisotropic conductive adhesive and encapsulant material

• US 5,136,365 A
• Filed: 09/27/1990
• Issued: 08/04/1992
• Est. Priority Date: 09/27/1990
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Pennisi, Robert W., Urbish, Glenn F., Papageorge, Marc V.
• Primary Examiner(s): James, Andrew J.
• Assistant Examiner(s): Crane, Sara W.
• Application Number:
  US07/588,889
• Time in Patent Office: 677 Days
• Field of Search: 357/81, 357/72, 357/80, 148/24, 148/25, 252/511, 252/514
• US Class Current: 257/783
• CPC Class Codes: H01L 21/563 Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• CPC Class Codes: H01L 2224/13111 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/29101 the principal constituent melting at a temperature of less than 400°C
• CPC Class Codes: H01L 2224/29111 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/2919 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/2929 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• 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 2224/29309 Indium [In] as principal constituent
• CPC Class Codes: H01L 2224/29311 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/29313 Bismuth [Bi] as principal constituent
• CPC Class Codes: H01L 2224/29316 Lead [Pb] as principal constituent
• CPC Class Codes: H01L 2224/2932 Antimony [Sb] as principal constituent
• CPC Class Codes: H01L 2224/29339 Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/73203 Bump and layer connectors
• CPC Class Codes: H01L 2224/81801 Soldering or alloying
• CPC Class Codes: H01L 2224/83191 wherein the layer connectors are disposed only on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83855 Hardening the adhesive by curing, i.e. thermosetting
• CPC Class Codes: H01L 2224/83862 Heat curing
• CPC Class Codes: H01L 23/4828 : Conductive organic material or pastes, e.g. conductive adhesives, inks
• CPC Class Codes: H01L 23/49883 : the conductive materials containing organic materials or pastes, e.g. for thick films for printed circuits H05K1/092
• CPC Class Codes: H01L 24/29 : of an individual layer connector
• CPC Class Codes: H01L 24/81 : using a bump connector
• CPC Class Codes: H01L 24/83 : using a layer connector
• 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 2924/00014 : 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 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01016 : Sulfur [S]
• CPC Class Codes: H01L 2924/01027 : Cobalt [Co]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01051 : Antimony [Sb]
• CPC Class Codes: H01L 2924/01067 : Holmium [Ho]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/0132 : Binary Alloys
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/0665 : Epoxy resin
• CPC Class Codes: H01L 2924/0781 : being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/07811 : Extrinsic, i.e. with electrical conductive fillers
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15787 : Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2924/351 : Thermal stress
• CPC Class Codes: H01L 2924/3512 : Cracking
• CPC Class Codes: H05K 2201/0145 : Polyester, e.g. polyethylene terephthalate [PET], polyethylene naphthalate [PEN]
• CPC Class Codes: H05K 3/321 : by conductive adhesives
• CPC Class Codes: H05K 3/323 : by applying an anisotropic conductive adhesive layer over an array of pads
• CPC Class Codes: H05K 3/3489 : Composition of fluxes; Methods of application thereof; Other methods of activating the contact surfaces

Abstract

An adhesive material 220 including a fluxing agent and metal particles 240 is applied to either a substrate 200 having a metallization pattern 210 or an electrical component 230. The component 230 is positioned on the substrate 210 and heated. During the heating step, the fluxing agent promotes adhesion of the metal particles 240 to the substrate metallization pattern 210 and the component, and the adhesive material 220 is cured, to mechanically interconnect and encapsulate the substrate 210 and the component 230.

Claims

1. An adhesive having a fluxing agent and metal particles for use in reflow soldering and interconnecting an electrical component and a substrate, comprising;

a thermoset resin,

a fluxing agent,

a curing agent, and

metal particles, said metal particles melting to form a metallurgical bond to the electrical component and the substrate during the reflow soldering, and said adhesive having the property of being anisotropically conductive after the reflow.

2. The adhesive of claim 1 wherein the thermoset resin is epoxy or polyester.

3. The adhesive of claim 1, wherein the fluxing agent comprises a compound having the formula:

##STR2## where R is an electron withdrawing group.

4. The fluxing agent of claim 3, wherein R is selected from the group consisting of fluorine, chlorine, bromine, iodine, sulfur, hydroxyl, nitrile, and benzyl.

5. The adhesive of claim 1, wherein the fluxing agent is malic acid.

6. The adhesive of claim 1, wherein the proportion of the fluxing agent in the adhesive ranges from about 0.1 to about 16 weight % of the adhesive.

7. The adhesive of claim 1, wherein the metal is selected from the group consisting of lead, tin, indium, bismuth, antimony, and silver.

8. The adhesive of claim 7, wherein the metal particles are an alloy of solder.

9. The adhesive of claim 1, wherein the size of the metal particles is greater than 1 micron but less than 20 microns.

10. The adhesive of claim 1, wherein the proportion of the metal particles is greater than 50 but less than 85 weight % of the adhesive.

11. An electrical component assembly, comprising:

an electrical component having a plurality of electrical terminations;

a component carrying substrate having a plurality of electrical terminations corresponding to the terminations of the electrical component; and

an anisotropically conductive adhesive material for connecting the electrical component to the substrate, comprising;

an epoxy resin,

a fluxing agent,

a curing agent, and

solder particles reflowed to form a metallurgical bond between and electrically connecting the electrical component and the substrate, said anisotropic adhesive material being disposed between and bonding the electrical component and the substrate, and having different conductivity in different directions.

12. The adhesive material of claim 11, wherein the fluxing agent comprises a compound having the formula:

##STR3## where R is an electron withdrawing group.

13. The fluxing agent of claim 12, wherein R is selected from the group consisting of fluorine, chlorine, bromine, iodine, sulfur, hydroxyl, nitrile, and benzyl.

14. The fluxing agent of claim 12, wherein the compound is malic acid.

15. The adhesive material of claim 11, wherein the proportion of the fluxing agent in the adhesive ranges from about 0.1 to about 16 weight % of the adhesive material.

16. The adhesive of claim 11, wherein the solder is selected from the group consisting of lead, tin, indium, bismuth, antimony, silver, and alloys thereof.

17. The adhesive of claim 11, wherein the size of the solder particles is greater than 1 micron but less than 20 microns.

18. The adhesive of claim 11, wherein the proportion of the solder particles is greater than 50 but less than 85 weight % of the adhesive.

19. The electrical component assembly of claim 11, wherein the component is an integrated circuit.