SOLDER PARTICLE, SOLDER PASTE, MANUFACTURE OF SOLDER PARTICLE AND METHOD OF MOUNTING DEVICE ON CIRCUIT BOARD

PROBLEM TO BE SOLVED: To prevent occurrence of defect in wire bonding by forming solder particles flat in shape so that no particles are rolled easily with the wind or the like, and generating a state where the surfaces of the particles are in contact with each other so that no particles are blown away or rolled over by a hot blast even if they are exposed from a solder paste layer. SOLUTION: A solder paste containing flat-shaped solder particles 11 is printed on a conductor layer on a wiring board, with devices temporarily fixed on the conductor layer, and then with the wiring board brought in a reflow furnace, preheating is performed by a hot blast. Since the flat solder particle 11 has a large contact surface, they stick to each other through a viscous compound in the solder paste to form a large mass, which therefore is hard to be blown away and rolled over by a hot blast. In manufacturing the flat solder particles 11, the solder particles in a quantity capable of monodispersion are sprayed on a press surface and given vibration in a horizontal direction, so that the spherical solder particles are crushed through press working by lowering the upper part of a metallic die, thereby forming the flat solder particles 11.