Abstract: A solder composition of the invention includes: a flux composition containing a component (A) in a form of a rosin-based resin, a component (B) in a form of an activator, a component (C) in a form of a solvent and a component (D) in a form of a thixotropic agent; and a component (E) in a form of a solder powder. The component (C) in a form of the solvent contains a component (C1) in a form of a isobornyl cyclohexanol and a component (C2) in a form of a solvent whose viscosity at 20 degrees C. is 10 mPa·s or less and whose boiling point ranges from 220 degrees C. to 245 degrees C.

Abstract: A solder composition of the invention includes: a flux composition containing a component (A) in a form of a rosin-based resin, a component (B) in a form of an activator, a component (C) in a form of a solvent and a component (D) in a form of a thixotropic agent; and a component (E) in a form of a solder powder. The component (C) in a form of the solvent contains a component (C1) in a form of a isobornyl cyclohexanol and a component (C2) in a form of a solvent whose viscosity at 20 degrees C. is 10 mPa·s or less and whose boiling point ranges from 220 degrees C. to 245 degrees C.

Abstract: There is provided an in-oil atomization method wherein a solder is fused and dispersed in a heated particle dispersion medium, the method being featured in that even if the quantity of the particle dispersion medium to be employed is relatively small, fine solder particles can be effectively obtained. Namely, this invention provides a method of manufacturing fine particles, wherein solder is fused in the heated particle dispersion medium to obtain a molten solder, which is then dispersed by means of an agitator to obtain molten solder particles which are subsequently cooled and solidify, the method being characterized in that the above dispersing step is performed in the presence of a particle coalescence-preventing agent. This invention also provides a fine metal particles-containing substance and a paste solder composition.

Abstract: There is provided a lead-free solder which makes it possible to reliably and accurately perform the inspection of various kinds of defective soldering in the inspection using an image inspection apparatus after the reflow soldering. According to this lead-free solder, the delustering of the metallic luster of fillet is realized in order to minimize the probability of generating a dark portion at the area where no defective soldering is existed and instead to increase the area of whitish portion which can be generated through the irregular reflection of beam. Specifically, this invention provides a lead-free solder comprising an Sn—Ag—Cu-based lead-free solder containing a small quantity of Bi and Sb as an element which is capable of generating a delustering component for minimizing metallic luster of the fillet.

Abstract: The invention provides an industrially efficient, low-cost, mass-production system for the process of producing fine solder powders using an in-oil atomization method wherein solder is melted in a heated dispersion medium for fine granulation. Molten solder melted in a solder melting tank and a mixture of a particle dispersion medium and a particle coalescence-preventing agent, prepared in a dispersion medium heating tank, are fed to a fine-granulation machine, in which dispersion energy is applied to obtain a dispersion of molten solder particles. The dispersion is processed in a solidifier-by-cooling to obtain a dispersion of solid solder particles, which is processed in a solid-liquid separator to separate the solid solder particles. The solid solder particles are washed and dried to obtain fine powders. The respective devices at these steps are connected together by way of piping, so that fine solder powders can continuously be produced.

Abstract: There is provided a lead-free solder which makes it possible to reliably and accurately perform the inspection of various kinds of defective soldering in the inspection using an image inspection apparatus after the reflow soldering. According to this lead-free solder, the delustering of the metallic luster of fillet is realized in order to minimize the probability of generating a dark portion at the area where no defective soldering is existed and instead to increase the area of whitish portion which can be generated through the irregular reflection of beam. Specifically, this invention provides a lead-free solder comprising an Sn—Ag—Cu-based lead-free solder containing a small quantity of Bi and Sb as an element which is capable of generating a delustering component for minimizing metallic luster of the fillet.

Abstract: There is provided an in-oil atomization method wherein a solder is fused and dispersed in a heated particle dispersion medium, the method being featured in that even if the quantity of the particle dispersion medium to be employed is relatively small, fine solder particles can be effectively obtained. Namely, this invention provides a method of manufacturing fine particles, wherein solder is fused in the heated particle dispersion medium to obtain a molten solder, which is then dispersed by means of an agitator to obtain molten solder particles which are subsequently cooled and solidify, the method being characterized in that the above dispersing step is performed in the presence of a particle coalescence-preventing agent. This invention also provides a fine metal particles-containing substance and a paste solder composition.