Abstract: Obtained are fine-pitched pad electrodes and also solder bumps with a large amount of solder and a less difference in the amount. First, in an inert liquid in a liquid tank, a substrate is positioned with a surface facing up. Subsequently, the inert liquid containing solder fine particles is fed from a solder fine particle forming unit to the liquid tank and the solder fine particles are dropped from a supply pipe onto the substrate in the inert liquid. The solder fine particles naturally fall down by the gravity, thereby reaching the substrate. The solder fine particles reached on the pad electrodes on the substrate stay there due to the gravity, and spread on the surfaces of the pad electrodes after the solder wet time, thereby forming solder coating.

Abstract: Obtained are fine-pitched pad electrodes and also solder bumps with a large amount of solder and a less difference in the amount. First, in an inert liquid (13) in a liquid tank (11), a substrate (20) is positioned with a surface (21) facing up. Subsequently, the inert liquid (13) containing solder fine particles (14) is fed from a solder fine particle forming unit (15) to the liquid tank (11) and the solder fine particles (14) are dropped from a supply pipe (16) onto the substrate (20) in the inert liquid (13). The solder fine particles (14) naturally fall down by the gravity, thereby reaching the substrate (20). The solder fine particles (14) reached on the pad electrodes on the substrate (20) stay there due to the gravity, and spread on the surfaces of the pad electrodes after the solder wet time, thereby forming solder coating.