High purity cobalt sputter target and process of manufacturing the same

Abstract

A high purity cobalt sputter target is disclosed which contains a face centered cubic (fcc) phase and a hexagonal close packed (hcp) phase, wherein the value of the ratio of X-ray diffraction peak intensity, I (200)/I (10 {overscore (1)}1), is smaller than the value of the same ratio in a high purity cobalt material obtained by cooling fcc cobalt to room temperature from the high temperature at which it is molten. High purity cobalt is defined as having an oxygen content of not more than 500 ppm, a Ni content of not more than 200 ppm, contents of Fe, Al and Cr of not more than 50 ppm each, and Na and K of less than 0.5 ppm. The disclosed sputter target is manufactured by subjecting the material to cold-working treatments (less than 422° C.). Annealing the material, at a temperature in the range 300-422° C. for several hours, between cold working treatments significantly increases the amount of cold work which could be imparted into the material. The high purity cobalt is deformed in such a way so as to cause the (0002) hcp plane to be tilted between 10-35° from the target normal. The aforementioned phase proportions and crystallographic texture significantly improves the sputtering efficiency and material utilization.