Anisotropic conductive adhesive
View Patent ↗An anisotropic conductive adhesive for anisotropic conductive connection of an electronic component to a wiring board under no pressure or a low pressure is prepared by dispersing conductive particles in a binder resin composition. A metal flake powder having a major axis of 10 to 40 μm, a thickness of 0.5 to 2 μm, and an aspect ratio of 5 to 50, is used as the conductive particles. The amount of the conductive particles contained in the anisotropic conductive adhesive is 5 to 35 mass %. This anisotropic conductive adhesive is supplied to a connection terminal of a wiring board, and a connection terminal of an electronic component is preliminarily connected to a connection terminal of a substrate while arranging the anisotropic conductive adhesive therebetween. Then, the electronic component is heated without applying a pressure or while applying a low pressure to the electronic component to connect the substrate with the electronic component.
1. An anisotropic conductive connection method comprising:
supplying an anisotropic conductive adhesive to a connection terminal of a wiring board;
preliminarily connecting a connection terminal of an electronic component to the connection terminal of the wiring board while arranging the anisotropic conductive adhesive therebetween; and
heating the electronic component while applying a pressure of 1 MPa or less to the electronic component to connect the wiring board with the electronic component and to completely or almost completely cure the adhesive;
wherein the adhesive comprises:
a binder resin composition and conductive particles that include a metal flake powder and are dispersed in the binder resin composition, wherein:
the metal flake powder enables electrical connection between the connection terminals and the conductive particles due to surface connection;
the metal flake powder has a major axis of 10 to 40 μm, a thickness of 0.5 to 2 μm, and an aspect ratio of 5 to 50; and
an amount of the conductive particles contained in the anisotropic conductive adhesive is 5 to 35 mass %.
2. The anisotropic conductive connection method according to claim 1 , wherein the metal flake powder is a nickel flake powder.
3. The anisotropic conductive connection method according to claim 1 , wherein the binder resin composition comprises an epoxy resin and an imidazole curing agent.
4. The anisotropic conductive connection method according to claim 1 , wherein the adhesive has a viscosity of 50 to 200 Pa·s at 25° C.
5. The anisotropic conductive connection method according to claim 1 , wherein a pressure of 0.1 to 1 MPa is applied to the electronic component during the preliminary connecting.
6. The anisotropic conductive connection method according to claim 1 , wherein the electronic component is heated without applying a pressure.
7. The anisotropic conductive connection method according to claim 2 , wherein the binder resin composition comprises an epoxy resin and an imidazole curing agent.
8. The anisotropic conductive connection method according to claim 2 , wherein the adhesive has a viscosity of 50 to 200 Pa·s at 25° C.
9. The anisotropic conductive connection method according to claim 3 , wherein the adhesive has a viscosity of 50 to 200 Pa·s at 25° C.
10. The anisotropic conductive connection method according to claim 7 , wherein the adhesive has a viscosity of 50 to 200 Pa·s at 25° C.