| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce residual resistivity increased by high temp. heating and to improve thermal conductivity and electric conductivity. SOLUTION: Oxygen-free copper of <=10ppm oxygen concentration is temporarily heated at >=700 deg.C, and this oxygen-free copper after heating is reheated at a temp. in the prescribed range centering around 600 deg.C for >=10min. By carrying out reheating at the temp. in the prescribed range as mentioned above, excess impurities over their limits of solid solubility at the reheating temp. are rapidly precipitated and their amounts in the form of solid solutions are reduced, and as a result, residual resistivity can be recovered and consequently thermal conductivity and electric conductivity can be improved.</p> |
