SOLDER FLUX AND SOLDER PASTE

摘要

A solder flux and a cream solder is provided to improve the thermal stability and to lighten the color by including the polymerized rosin or the hydrogenation polymerized rosin. A solder flux and a cream solder comprises a metal content of less than 50 ppm and the rosin-based compound(A) whose ethanol solution is 1.0muS/cm or less, if it is 20 weight% ethanol solution. The content of the seventeenth group element and the first group element excepting the hydrogen include in the rosin-based compound is 20 ppm or less. The rosin-based compound is obtained by hydrogenating the additive reactant of alpha, beta - unsaturated carboxylic acid(a) and the rosin(b).