COMPOSITIONS AND METHODS FOR PROVIDING ANISOTROPIC CONDUCTIVE PATHWAYS AND BONDS BETWEEN TWO SETS OF CONDUCTORS

• Main Authors: MCARDLE, CIARAN BERNARD, BURKE, JOSEPH
• Format: Patent
• Language: English; French
• Published: 03.08.1995
• Edition: 6
• Subjects: ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; ADHESIVES; BASIC ELECTRIC ELEMENTS; CABLES; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; CHEMISTRY; CONDUCTORS; CURRENT COLLECTORS; DYES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; INDUCTANCES; INSULATORS; LINE CONNECTORS; MAGNETS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; PAINTS; POLISHES; PRINTED CIRCUITS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING ORDIELECTRIC PROPERTIES; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; SEMICONDUCTOR DEVICES; TRANSFORMERS; USE OF MATERIALS AS ADHESIVES

The invention provides a composition (3) comprising: (i) a ferrofluid comprising a colloidal suspension (4) of ferromagnetic particles in a nonmagnetic carrier liquid, and (ii) a plurality of electrically-conductive particles (5) having substantially uniform sizes and shapes, dispersed in the ferrofluid. Various types of substantially non-magnetic electricallyconductive particles (5) are described. Application of a substantially uniform magnetic field by magnet means (8) to the composition (3) causes the electrically-conductive particles (5) to form a regular pattern (9). The composition is used for providing anisotropic conductive pathways (9a, 9b) between two sets of conductors (2a, 2b; 7a, 7b) in the electronics industry. The composition may be a curable adhesive composition which bonds the conductors. Alternatively or in addition the electrically-conductive particles may have a latent adhesive property e.g. the particles may be solder particles. The ferrofluid may be a colloidal suspension of ferromagnetic particles in a liquid monomer.