Solderable anisotropically conductive composition and method of using same
AssigneeW. R. Grace & Co.-Conn.
InventorEckart Mathias
Life of this patent
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Abstract
A novel anisotropically conductive solder paste and a method of use thereof to join metallic parts in electronic manufacturing processes, in particular surface-mount electronic manufacturing processes. The solder paste is fluxless and reflowable for purposes of repair and achieves electrical anisotropy by soldering component leads to circuit board pads, while maintaining electrical insulation properties between adjacent joints.
Claims15
An anisotropically-conductive solder paste composition which comprises finely-divided metal alloy particles dispersed in a solution of an organic polymer in an organic solvent which has a boiling point above the softening temperature of the polymer and no higher than the melting point of the metal alloy particles, wherein the polymer has a softening temperature at or below the melting point of the metal alloy particles and where said composition is free of a fluxing agent.
A surface mount electronic manufacturing process comprising
- a) applying an anisotropically-conductive solder paste onto the pads and spaces of a printed circuit board;
- b) placing electronic surface mount components onto the printed circuit board wherein the leads of the electronic components are in contact with the solder paste coated pads;
- c) heating the printed circuit board at a temperature and for a period of time sufficient to cause the solder paste to melt;
- and
- d) allowing the printed circuit board to cool;
- wherein the solder paste is free of a fluxing agent and comprises finely-divided metal alloy particles dispersed in a solution of an organic polymer in an organic solvent which has a boiling point above the softening temperature of the polymer and no higher than the melting temperature of the metal alloy particles and wherein the polymer has a softening temperature at or below the melting point of the metal alloy particles.
Dependencies are inferred from the claim text.