High-purity copper-chromium alloy sputtering target
View Patent ↗Provided is a high-purity copper-chromium alloy sputtering target comprising 0.1 to 10 wt % of Cr and the remainder being Cu and inevitable impurities, wherein when the number of precipitated Cr grains in a 100 μm square area is counted at different five areas randomly selected on the surface of the target, the difference between the largest and the smallest numbers of counted precipitated Cr grains is less than 40. The term “precipitated Cr grains” refers to the grains each having a Cr content of 70% or more and having a grain size of 1 to 20 μm. Thus, a thin film having excellent uniformity can be formed by adding an appropriate amount of a Cr element to copper and reducing the in-plane Cr variation of the sputtering target. In particular, the invention provides a high-purity copper-chromium alloy sputtering target that is useful for improving the yield and the reliability of semiconductor products, which have been progressing in miniaturization and integration.
1. A high-purity copper-chromium alloy sputtering target produced from a cast ingot comprising 0.1 to 10 wt % of Cr and the remainder being Cu and inevitable impurities, wherein when the number of precipitated Cr grains in a 100 μm square area is counted at different five areas randomly selected on the surface of the target, the difference between the largest and the smallest numbers of counted precipitated Cr grains is less than 40; the precipitated Cr grains to be counted are grains each having a Cr content of 70% or more and a grain size of 1 to 20 μm.
2. The high-purity copper-chromium alloy sputtering target according to claim 1 , wherein the contents of Na and K are each 5 wt ppm or less, the contents of Fe, Al, and Mg are each 1 wt ppm or less, the contents of S and Cl are each 1 wt ppm or less, the contents of C and O are each 10 wt ppm or less, and the contents of U and Th are each 1 wt ppb or less.
3. The high-purity copper-chromium alloy sputtering target according to claim 1 , wherein the contents of S and Cl are each 1 wt ppm or less.
4. The high-purity copper-chromium alloy sputtering target according to claim 3 , wherein the contents of C and O are each 10 wt ppm or less.
5. The high-purity copper-chromium alloy sputtering target according to claim 3 , wherein the contents of U and Th are each 1 wt ppb or less.
6. A high-purity copper-chromium alloy sputtering target produced from a cast ingot comprising 0.1 to 5 wt % of Cr and the remainder being Cu and inevitable impurities, wherein, when a number of precipitated Cr grains having a Cr content of 70% or more and a grain size of 1 to 20 μm in a 100 μm square area is counted at five different areas on a surface of the target, a difference between a largest number and a smallest number of counted precipitated Cr grains is less than 40.
7. The high-purity copper-chromium alloy sputtering target according to claim 6 , wherein said target has 5 wt ppm or less of each of Na and K, 1 wt ppm or less of each of Fe, Al, and Mg, 1 wt ppm or less of each of S and Cl, 10 wt ppm or less of each of C and O, and 1 wt ppb or less of each of U and Th.