| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide highly-pure indium with a reduced amount ofαrays responding to the requirement of highly purified solder material or indium particularly used near a semiconductor device since software errors caused byαrays generated from the material near a semiconductor chip increasingly occur because of high density and high capacity of the recent semiconductor.SOLUTION: A method of producing highly purified indium comprises: vaporizing to remove impurities with a vapor pressure higher than that of indium by firstly distilling a raw material indium heated at 1,000°C or higher; thereafter once cooling to a room temperature; successively heating again a residue containing indium to melt; and thereafter, while vaporizing indium at 1,100-1,500°C, having impurities with a vapor pressure lower than that of indium remain and remove (by secondly distilling ), thereby reducingPb contained in indium to 0.1 ppm or less so that the amount ofαrays is 0.002 cph/cmor less.</p> |
