Electronic devices employing adhesive interconnections including plated particles

• US 6,297,564 B1
• Filed: 03/25/1999
• Issued: 10/02/2001
• Est. Priority Date: 04/24/1998
• Status: Expired due to Fees

• Current Assignee: Amerasia International Technology, Inc.
• Original Assignee: Amerasia International Technology, Inc.
• Inventors: Chung, Kevin Kwong-Tai
• Primary Examiner(s): Chaudhuri, Olik
• Assistant Examiner(s): PIZARRO CRESPO, MARCOS D
• Application Number:
  US09/276,259
• Time in Patent Office: 922 Days
• Field of Search: 257/783, 257/787, 156/306.6, 438/118, 438/112, 438/124, 438/127
• US Class Current: 257/783
• CPC Class Codes: H01L 2224/1329 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/133 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 2224/16237 the bump connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/29101 the principal constituent melting at a temperature of less than 400°C
• 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 2224/293 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 2224/29386 with a principal constituent of the material being a non metallic, non metalloid inorganic material
• CPC Class Codes: H01L 2224/2939 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/294 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 2224/29499 Shape or distribution of the fillers
• CPC Class Codes: H01L 2224/2989 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/8319 Arrangement of the layer connectors prior to mounting
• CPC Class Codes: H01L 2224/83855 Hardening the adhesive by curing, i.e. thermosetting
• CPC Class Codes: H01L 2224/8388 Hardening the adhesive by cooling, e.g. for thermoplastics or hot-melt adhesives
• CPC Class Codes: H01L 2224/83885 Combinations of two or more hardening methods provided for in at least two different groups from H01L2224/83855 - H01L2224/8388, e.g. for hybrid thermoplastic-thermosetting adhesives
• CPC Class Codes: H01L 24/29 of an individual layer 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 2924/01029 : 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 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01087 : Francium [Fr]
• 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 2924/15787 : Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/19043 : being a resistor
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/3512 : Cracking
• CPC Class Codes: H05K 2201/0129 : Thermoplastic polymer, e.g. auto-adhesive layer; Shaping of thermoplastic polymer
• CPC Class Codes: H05K 2201/0133 : Elastomeric or compliant polymer elastomeric conductor H05K2201/0314
• CPC Class Codes: H05K 2201/10636 : Leadless chip, e.g. chip capacitor or resistor
• CPC Class Codes: H05K 2201/10674 : Flip chip
• CPC Class Codes: H05K 2201/10977 : Encapsulated connections applying non-metallic protective coatings for encapsulating mounted components H05K3/284
• CPC Class Codes: H05K 2201/10984 : Component carrying a connection agent, e.g. solder, adhesive soldering leadless components having an array of bottom contacts H05K3/3436; BGA components H05K2201/10734
• CPC Class Codes: H05K 3/244 : Finish plating of conductors, especially of copper conductors, e.g. for pads or lands selective plating methods H05K3/243; finish plating of conductors made by printing techniques H05K3/246; solder as finish H05K3/3457, e.g. by plating H05K3/3473
• CPC Class Codes: H05K 3/321 : by conductive adhesives
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

Electronic devices formed by bonding and interconnecting one or more electronic components to an electronic circuit substrate employ specialized adhesives comprising gold-plated, platinum-plated and/or palladium-plated particles in a polymeric adhesive system which may include thermoplastic or thermosetting resins. These plated particles beneficially provide electrical conductivity through the polymeric adhesive for electrically interconnecting contact pads on the electronic components with contact pads on the electronic circuit substrate and provide resistance to migration of metal, thereby enabling interconnection and bonding at very fine pitch and spacing. Polymers with substantial flexibility and a low glass transition temperature are preferred over more rigid resins. Particles having a morphology and shapes that include higher aspect ratios are preferred because lesser volume fraction loading is needed to establish good electrical conductivity through the polymeric adhesive. A combination of high aspect ratio plated particles and spherical particles may be employed to enhance the thermal conductivity of the polymeric adhesive without substantially increasing the overall cost of the conductive polymer adhesive system. Electronic devices employing the invention include such applications as semiconductor die attachment, flip-chip device interconnection, electronic component attachment, electronic substrate attachment to printed wiring boards, jumper interconnection, and the like.

Claims

1. An electronic device comprising:

a substrate having contact pads thereon, wherein the contact pads are coated with an oxidation-resistant metal;

a semiconductor chip having contact pads thereon coated with an oxidationresistant metal, wherein said semiconductor chip is connected in a flip chip manner to said substrate, wherein said substrate and said semiconductor chip have corresponding contact pads, wherein connections between corresponding contact pads on said semiconductor chip and on said substrate are made with a conductive adhesive including;

an adhesive selected from the group consisting of thermosetting and thermoplastic polymer adhesives, a blend thereof and a copolymer thereof, wherein the polymer adhesive has a modulus of elasticity of less than 300,000 psi at temperatures above a glass transition temperature of 25°

C. or lower and has more than 30% elongation of linear dimension before fracture, and

a multiplicity of core particles formed of a material other than a precious metal selected from the group consisting of copper, aluminum, nickel, carbon, graphite, glass, and polymers, wherein said core particles are plated with a precious metal selected from the group consisting of gold, platinum and palladium, and wherein said plating with a precious metal is about 10% to about 30% by weight of the core particle weight.

2. The electronic device of claim 1 wherein said core particles include at least one of flakes, rods, and fibers.

3. The electronic device of claim 1 wherein said core particles have an aspect ratio of at least 2:

1.

4. An electronic circuit assembly comprising:

a plurality of electronic components including at least one semiconductor chip and at least one of a resistor and a capacitor, and each including contacts having an oxidation-resistant metal coating thereon, and

a substrate having contact pads having an oxidation-resistant metal coating thereon to which contacts of said electronic components are mounted, wherein said electronic components including said semiconductor chip are connected in a flip chip manner to corresponding contact pads on said substrate, and wherein connections between corresponding contact pads of said electronic components and of said substrate include a conductive adhesive including;

an adhesive selected from the group consisting of thermosetting and thermoplastic polymer adhesives, a blend thereof and a copolymer thereof, wherein the polymer adhesive has a modulus of elasticity of less than 300,000 psi at temperatures above a glass transition temperature of 25°

C. or lower and has more than 30% elongation of linear dimension before fracture, and

a multiplicity of core particles formed of a material other than a precious metal formed of a material selected from the group consisting of copper, aluminum, nickel, carbon, graphite, glass, and polymers, wherein said core particles are plated with a precious metal selected from the group consisting of gold, platinum and palladium, and wherein said plating with a precious metal is about 10% to about 30% by weight of the core particle weight.

5. The electronic circuit assembly of claim 4 wherein said core particles include at least one of flakes, rods, and fibers.

6. The electronic circuit assembly of claim 4 wherein said core particles have an aspect ratio of at least 2:

1.

7. An electronic device comprising:

at least one electronic component having a plurality of contact pads coated with an oxidation-resistant metal on a first surface thereof;

a substrate having a plurality of contact pads coated with an oxidation-resistant metal on a first surface thereof, wherein said contact pads of said substrate are arranged in a pattern to correspond to the contact pads on said electronic component and wherein said electronic component and said substrate are positioned with their respective first surfaces proximate each other; and

a plurality of conductive adhesive connections between respective ones of the contact pads of said electronic component and of the corresponding contact pads of said substrate, wherein said conductive adhesive includes;

an adhesive selected from the group consisting of thermosetting polymer adhesives, thermoplastic polymer adhesives, and blends, copolymers and combinations thereof, wherein the polymer adhesive has a modulus of elasticity of less than 300,000 psi at temperatures above a glass transition temperature of 25°

C. or lower and has more than 30% elongation of linear dimension before fracture, and

a multiplicity of core particles formed of a material other than a precious metal selected from the group consisting of copper, aluminum, nickel, carbon, graphite, glass, and polymers, wherein said core particles are plated with a precious metal selected from the group consisting of gold, platinum and palladium, and wherein said plating with a precious metal is about 10% to about 30% by weight of the core particle weight.

8. The electronic device of claim 7 wherein said core particles include at least one of flakes, rods, and fibers.

9. The electronic device of claim 7 wherein said core particles have an aspect ratio of at least 2:

1.

10. An electronic device comprising:

a substrate having contact pads thereon;

a semiconductor chip having contact pads thereon, wherein said semiconductor chip is connected in a flip chip manner to said substrate, wherein said substrate and said semiconductor chip have corresponding contact pads, wherein connections between corresponding contact pads on said semiconductor chip and on said substrate are made with a conductive adhesive including;

an adhesive selected from the group consisting of thermosetting and thermoplastic polymer adhesives, a blend thereof and a copolymer thereof, wherein the polymer adhesive has a modulus of elasticity of less than 300,000 psi at temperatures above a glass transition temperature of 25°

C. or lower and has more than 30% elongation of linear dimension before fracture, and

a multiplicity of core particles formed of a material other than a precious metal, wherein said core particles are plated with a precious metal selected from the group consisting of gold, platinum and palladium, and wherein said plating with a precious metal is about 10% to about 30% by weight of the core particle weight.

11. The electronic device of claim 10 wherein said core particle is formed of a material selected from the group consisting of copper, aluminum, nickel, carbon, graphite, glass, and polymers.

12. The electronic device of claim 10 wherein said core particles include at least one of flakes, rods, and fibers.

13. The electronic device of claim 10 wherein said core particles have an aspect ratio of at least 2:

1.

14. An electronic circuit assembly comprising:

a plurality of electronic components including at least one semiconductor chip and at least one of a resistor and a capacitor, and

a substrate having contact pads to which contacts of said electronic components are mounted, wherein said electronic components including said semiconductor chip are connected in a flip chip manner to corresponding contact pads on said substrate, and wherein connections between corresponding contact pads of said electronic components and of said substrate include a conductive adhesive including;

an adhesive selected from the group consisting of thermosetting and thermoplastic polymer adhesives, a blend thereof and a copolymer thereof, wherein the polymer adhesive has a modulus of elasticity of less than 300,000 psi at temperatures above a glass transition temperature of 25°

C. or lower and has more than 30% elongation of linear dimension before fracture, and

a multiplicity of core particles formed of a material other than a precious metal, wherein said core particles are plated with a precious metal selected from the group consisting of gold, platinum and palladium, and wherein said plating with a precious metal is about 10% to about 30% by weight of the core particle weight.

15. The electronic circuit assembly of claim 14 wherein said core particle is formed of a material selected from the group consisting of copper, aluminum, nickel, carbon, graphite, glass, and polymers.

16. The electronic circuit assembly of claim 14 wherein said core particles include at least one of flakes, rods, and fibers.

17. The electronic circuit assembly of claim 14 wherein said core particles have an aspect ratio of at least 2:

1.

18. An electronic device comprising:

at least one electronic component having a plurality of contact pads on a first surface thereof;

a substrate having a plurality of contact pads on a first surface thereof, wherein said contact pads of said substrate are arranged in a pattern to correspond to the contact pads on said electronic component and wherein said electronic component and said substrate are positioned with their respective first surfaces proximate each other; and

a plurality of conductive adhesive connections between respective ones of the contact pads of said electronic component and of the corresponding contact pads of said substrate, wherein said conductive adhesive includes;

an adhesive selected from the group consisting of thermosetting polymer adhesives, thermoplastic polymer adhesives, and blends, copolymers and combinations thereof, wherein the polymer adhesive has a modulus of elasticity of less than 300,000 psi at temperatures above a glass transition temperature of 25°

C. or lower and has more than 30% elongation of linear dimension before fracture, and

a multiplicity of core particles formed of a material other than a precious metal, wherein said core particles are plated with a precious metal selected from the group consisting of gold, platinum and palladium, and wherein said plating with a precious metal is about 10% to about 30% by weight of the core particle weight.

19. The electronic device of claim 18 wherein said core particle is formed of a material selected from the group consisting of copper, aluminum, nickel, carbon, graphite, glass, and polymers.

20. The electronic device of claim 18 wherein said core particles include at least one of flakes, rods, and fibers.

21. The electronic device of claim 18 wherein said core particles have an aspect ratio of at least 2:

1.