Method for producing a multi-layer circuit board using anisotropic electro-conductive adhesive layer

• US 6,544,428 B1
• Filed: 09/26/2000
• Issued: 04/08/2003
• Est. Priority Date: 08/12/1996
• Status: Expired due to Fees

• Current Assignee: Shinko Electric Industries Company Limited (Fujitsu Limited)
• Original Assignee: Shinko Electric Industries Company Limited (Fujitsu Limited)
• Inventors: Higashi, Mitsutoshi
• Primary Examiner(s): Gulakowski, Randy
• Application Number:
  US09/669,729
• Time in Patent Office: 924 Days
• Field of Search: 216/13, 216/15, 216/17, 216/18, 156/47, 156/50, 156/55, 156/60, 174/264
• US Class Current: 216/13
• 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 2224/0231 Manufacturing methods of the redistribution layers
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/73203 Bump and layer connectors
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 23/49827 Via connections through the substrates, e.g. pins going through the substrate, coaxial cables H01L23/49822, H01L23/49833, H01L23/4985, H01L23/49861 take precedence
• CPC Class Codes: H01L 23/49833 the chip support structure consisting of a plurality of insulating substrates
• 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 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: H05K 2203/0195 Tool for a process not provided for in H05K3/00, e.g. tool for handling objects using suction, for deforming objects, for applying local pressure
• CPC Class Codes: H05K 2203/1189 Pressing leads, bumps or a die through an insulating layer
• CPC Class Codes: H05K 3/323 by applying an anisotropic conductive adhesive layer over an array of pads
• CPC Class Codes: H05K 3/4084 by deforming at least one of the conductive layers

Abstract

An anisotropic electro-conductive adhesive layer 14 including an adhesive 15 made of a thermosetting or thermoplastic resin containing electro-conductive particles 16 dispersed therein is formed on a basic circuit board 11 carrying a first circuit pattern 12. A second circuit pattern 18 is formed on the anisotropic electro-conductive adhesive layer 14. An end of the second circuit pattern 18 is curved into the anisotropic electro-conductive adhesive layer 14 to be electrically connected with first circuit pattern 12 via the electro-conductive particles 16. Thereby, the production process can be simplified and the production cost can be reduced. Also, the micro-circuit patterns can be arranged at a high density.

Claims

1. A method for producing a multilayer circuit board using an anisotropic electro-conductive adhesive layer, comprising the following steps of:

a) preparing a substrate carrying a first circuit pattern thereon;

b) forming an anisotropic electro-conductive adhesive layer consisting of a thermosetting or thermoplastic resin adhesive containing electro-conductive particles dispersed therein on a surface of the substrate carrying the first circuit pattern;

c) forming an electro-conductive layer on the anisotropic electro-conductive adhesive layer, which is then processed to a second circuit pattern; and

d) heating and softening the anisotropic electro-conductive adhesive layer to enhance the curvature of an end of the second circuit pattern into the anisotropic electro-conductive adhesive layer to be closer to the substrate whereby the second circuit pattern is electrically connected to the first circuit pattern via the electro-conductive particles.

2. A method for producing a multilayer circuit board as defined by claim 1, wherein the above steps b) to d) are repeated to form three layers or more of circuit patterns overlaid with each other.

3. A method for producing a multilayer circuit board as defined by claim 2, wherein the anisotropic electro-conductive adhesive layer is an epoxy type thermosetting resin containing metallic particles dispersed therein.

4. A method for producing a multilayer circuit board as defined by claim 2, wherein the metallic particle is made of at least one selected from a group consisting of solder, nickel or gold.

5. A method for producing a multilayer circuit board using an anisotropic electro-conductive adhesive layer is provided, comprising the steps of:

a) forming a conductive layer on an anisotropic electro-conductive adhesive film prepared by dispersing electro-conductive particles in an adhesive consisting of a thermosetting or thermoplastic resin;

b) forming a second circuit pattern on the conductive layer;

c) overlaying the anisotropic electro-conductive adhesive layer on a substrate carrying a first circuit pattern; and

d) heating and softening the anisotropic electro-conductive adhesive layer to enhance the curvature of an end of the second circuit-pattern into the anisotropic electro-conductive adhesive layer whereby the second circuit pattern is electrically connected to the first circuit pattern via the electro-conductive particles.

6. A method for producing a multilayer circuit board as defined by claim 5, wherein the above steps a) to c) may be repeated to form three layers or more of circuit patterns overlaid with each other and the step d) may be simultaneously carried out for all the layers.