| 摘要 |
<p>A high purity ruthenium sputtering target suitable for use in forming a semiconductor thin film, having a low content of impurities and being reduced in occurrence of particles, which may be prepared by a method comprising adding a crude ruthenium powder into a sodium hydroxide solution, blowing into the resulting mixture a chlorine gas and an ozone-containing gas at the same time or firstly a chlorine gas and subsequently an ozone-containing gas, to thereby form ruthenium tetraoxide, allowing a solution of hydrochloric acid or a mixture of hydrochloric acid and ammonium chloride to absorb the ruthenium tetraoxide, evaporating the resultant solution to dryness, roasting the resulting ruthenium salt in a hydrogen atmosphere to give a high purity ruthenium powder, and subjecting the ruthenium powder to hot press or EB dissolution, to thereby prepare a high purity ruthenium sputtering target, which has the respective contents of carbon, oxygen and chlorine elements of 100 ppm or less.</p> |
