| 摘要 |
PROBLEM TO BE SOLVED: To obtain a solder paste containing leadless solder powder having a low melting point by consisting the solder paste of metallic powder including a combination of >=2 kinds of metals capable of forming an intermetallic compound and incorporating the unreacted phase prior to the formation of the intermetallic compound and an amorphous phase therein. SOLUTION: Preferably two or more kinds of the metals capable of forming the intermetallic compound are the metals selected from the group consisting of Sn, Ag, Cu, Bi, Zn, In, Au, Ni, Sb, Pd, Pt, and Ge and the combinations of >=2 kinds of the metals capable of forming the intermetallic compound are the combinations of the metals selected from the group consisting of Cu-Sn, Ag-Sn, Au-Bi, Au-In, Ni-Sn, Ag-Sb, Bi-In, Cu-Ge, In-Pd, Sb-Zn, etc. The leadless solder powder is obtained by further adding >=1 kind of metals to the metals and metal combinations described above. The grain size of the powder is 10 nm to 100μm. Since the leadless solder powder does not contain hazardous lead, the powder has the excellent safety of soldering work and does not adversely affect the environment at the time of disposal.
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