COMPOSITION FOR SOLDER PASTE

摘要

PURPOSE:To obtain a solder paste which is hardly oxidizable after coating until soldering with the solder paste for a printed wiring board by limiting the particle size of solder powder. CONSTITUTION:Solder powder having a particle size larger than 5mu is used to form a compsn. for a solder paste. If the solder powder having the larger particle size is used in such a way, the compsn. is made stable to air oxidation. The effect of preventing the oxidation is remarkable perticularly when the coated solder paste is dried by hot wind. However if the particle size of the solder powder is too large, the coatability in the stage of, for example, printing the paste is poor and therefore the adequate partizle size is about 150mu in max. in said respect.