| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a Ta sputtering target having a uniform crystalline microstructure and a method for the production of the same. <P>SOLUTION: A Ta ingot is subjected to a forging pattern over at least 3 times or not less than 3 times, wherein each forging pattern is äa cold forging step comprising stamp-forging and upset-forging operations alternatively repeated over at least 3 times or not less than 3 times}, and is also subjected to in-process vacuum heat-treating carried out between every successive two forging patterns to thus prepare a billet. From this billet, a sputtering target is produced. At this time, an ingot having an aspect ratio (length/diameter) ranging from 0.7 to 1.5 is used, and the change in shape of the ingot during the stamp-forging and upset-forging operations is performed within an aspect ratio (length/diameter) ranging from 0.7 to 1.5. Further, the billet is subjected to cold rolling in at least 4 axial directions at a total draft percentage ranging from 65 to 75%, and thereafter, the rolled plate is subjected to vacuum heat-treating at a temperature ranging from 850 to 950°C. The sputtering target has an average grain size ranging from 30 to 50μm and whose grain size never varies widely. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
