Patent ID: 6423154
Filing Date: 2002-07-23
Classification: B23K,H05K

Abstract:
A solder paste particularly adapted for use in a method of solder coating a metallic pad provided on a surface of a substrate, whereby at least a surface of the pad is provided with a deposit of solder paste, after which the substrate is at least partially subjected to a heating process, which heating process induces localized precipitation of an essentially continuous metallic solder layer out of the solder paste, said localized precipitation occurring on the pad but not on said surface of the substrate outside borders of the pad, subsequent to which any unwanted solder paste debris on the substrate outside borders of the pad is removed, characterized in that the solder paste comprises a suspension of metallic solder particles the concentration of which metallic solder particles in the paste being about 5-11 vol. % at STP, which metallic solder particles having an average diameter of about 20-30 &mgr;m and which metallic solder particles, when molten, have a surface energy lower than the critical surface energy of the metallic pad but higher than the critical surface energy of said surface of the substrate outside borders of the pad and which metallic solder particles within the paste lying on the pad, when heated, fusing together into an essentially continuous solder layer and which metallic solder particles outside borders of the pad, when heated, forming mutually-isolated solder beads removable subsequent to heating.