Copper alloy sputtering target and method for manufacturing the target
View Patent ↗A copper alloy sputtering target most suitable for formation of an interconnection material of a semiconductor device, particularly for formation of a seed layer, characterized in that the target contains 0.4 to 5 wt % of Sn, and the structure of the target does not substantially contain any precipitates, and the resistivity of the target material is 2.2 μΩcm or more. This target enables formation of an interconnection material of a semiconductor device, particularly a uniform seed layer stable during copper electroplating and is excellent in sputtering deposition characteristics. A method for manufacturing such a target is also disclosed.
1. A sputtering target for forming a seed layer of a semiconductor device, comprising: a copper alloy sputtering target containing 0.2 to 5 wt % of Al and having a sputtering face, said target having a resistivity of 2.2 μΩcm or more and an average crystal grain size of 50 μm or less, said target having a ratio I(111)/(200) of an X-ray diffraction peak intensity I(111) of a (111) face and an X-ray diffraction peak intensity I(200) of a (200) face of 2.2 or more in said sputtering face, and variation in I(111)/I(200) in said sputtering face is respectively within ±30%.
2. A copper alloy sputtering target according to claim 1 , wherein said target contains 0.5 to 1 wt % of Al.
3. A sputtering target for forming a seed layer of a semiconductor device, comprising: a copper alloy sputtering target containing 0.2 to 5 wt % of an alloying component of Al and having a sputtering face, said target having a resistivity of greater than a resistivity of a copper alloy having the same composition in a thermal equilibrium state and an average crystal grain size of 50 μm or less, wherein a ratio I(111)/I(200) of an X-ray diffraction peak intensity I(111) of a (111) face and an X-ray diffraction peak intensity I(200) of a (200) face is 2.2 or more in said sputtering face, and variation in I(111)/I(200) in said sputtering face is respectively within ±30%.
4. A copper alloy sputtering target according to claim 3 , wherein said target contains a total of 0.5 to 1 wt % of Al.
5. A copper alloy sputtering target according to claim 3 , wherein an increase in resistivity due to said alloying component in said target is 1.2 times or more than that of said copper alloy in said thermal equilibrium state.
6. A copper alloy sputtering target according to claim 3 , wherein variation in average grain size by location is within ±20%.
7. A copper alloy sputtering target according to claim 3 , wherein variation in the content of said alloying component of Al by location in said target is within 0.2%.
8. A copper alloy sputtering target according to claim 3 , wherein each of Na and K contained within said target is 0.1 ppm or less; each of Fe, Ni, Cr and Ca contained within said target is 1 ppm or less; each of U and Th contained within said target is 1 ppb or less, oxygen contained in said target is 5 ppm or less, hydrogen contained in said target is 2 ppm or less; and unavoidable impurities excluding alloying elements are 10 ppm or less.
9. A copper alloy sputtering target according to claim 1 , wherein each of Na and K contained within said target is 0.5 ppm or less; each of Fe, Ni, Cr and Ca contained within said target is 2 ppm or less; each of U and Th contained within said target is 1 ppb or less, oxygen contained in said target is 5 ppm or less, hydrogen contained in said target is 2 ppm or less; and unavoidable impurities excluding alloying elements are 50 ppm or less.
10. A copper alloy sputtering target according to claim 1 , wherein variation in average grain size by location is within ±20%.
11. A copper alloy sputtering target according to claim 1 , prepared by a process comprising the steps of:
obtaining a high purity copper alloy ingot by vacuum melting;
performing at least one of hot forging and hot rolling to said high purity copper alloy ingot;
thereafter, cold rolling said high purity copper alloy; and
thereafter sandwiching said high purity copper alloy with copper plates underwater and performing forced cooling thereto.
12. A copper alloy sputtering target for forming a seed layer of a semiconductor device, comprising:
a sputtering target body consisting of copper and 0.5 to 1 wt % of Al, said body having a sputtering face, an average crystal grain size of 50 μm or less, and a resistivity of 2.2 μΩcm or more;
said target having a ratio I(111)/I(200) of an X-ray diffraction peak intensity I(111) of a (111) face and an X-ray diffraction peak intensity I(200) of a (200) face of 2.2 or more in said sputtering face, and a variation in I(111)/I(200) in said sputtering face of respectively within ±30%.
13. A copper alloy sputtering target according to claim 12 , wherein said resistivity of said sputtering target body is 2.8 to 4.3 μΩ·cm.
14. A copper alloy sputtering target according to claim 12 , wherein said ratio I(111)/I(200) in said sputtering face is of 2.2 to 2.25.