SOLDER POWDER, FLUX, SOLDER PASTE, METHOD FOR SOLDERING, SOLDERED CIRCUIT BOARD AND SOLDERED JUNCTION PRODUCT

摘要

A solder powder, flux and solder paste which have excellent storage stability and reflow characteristics as well as a soldering method, a circuit board, a method for junction of electronic parts and a junction product which are ready for employment of a finer pitch and diversification of parts are provided. Use is made of a solder powder having a content of particles having a size of 20 mu m or less of 30 % or less in terms of the number of particles and having a oxygen content of 500 ppm or less. Or use is made of a flux which is comprised of an organic acid component comprising an organic acid ester and an ester decomposition catalyst, an organic halide, a reducing agent and a pH adjusting agent. Or a solder paste containing the aforementioned flux and solder powder has a water content of 0.5 wt.% or less.