METHOD FOR SOLDERING AND SOLDERED JOINT

摘要

A method for soldering, characterized as comprising a step of coating a Cu electrode of an electronic device with a rust-proof coating film comprising an organic compound containing N, and a step of forming a soldered joint on the resulting coated Cu electrode by use of a soldering material comprising 2.0 wt % or more and less than 3 wt % of Ag, 0.5 to 0.8 wt %, with the balance of the material being Sn and inevitable impurities. The soldering material may further comprise at least one element selected from the group consisting of Sb, In, Au, Zn, Bi and Al in an amount of 3 wt % in total. The method for soldering can be employed for providing, with no increase in production cost, a soldered joint which is free from the adverse effect on the environment and can exhibit a joint strength comparable to that with the conventional Pb-Sn solder.