| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a non-leaded In-based solder alloy which can be joined at 260°C or lower of soldering temperature, can absorb mechanical stress caused by a difference in a thermal expansion coefficient between a chip and a package, can absorb mechanical stress even during surface mounting and is suitable for a CPU for a server. <P>SOLUTION: The non-leaded In-based solder alloy is mainly composed of In and does not contain Pb, and either one or more elements of Au, Ag, Cu, Sb and Zn are added to the non-leaded In-based solder alloy. Casting is performed by setting a temperature difference ΔT between a molten metal temperature and a mold temperature during melting casting to be 300°C or higher, and warm extruding of its ingot is performed at 30-100 °C. Thus, the non-leaded In-based solder alloy, in which an average grain size of an intermetallic compound or primary crystal within the solder alloy is controlled to 25 μm or less, can be provided. <P>COPYRIGHT: (C)2013,JPO&INPIT |
