Patent ID: 8123875

Claim:
An Ag sputtering target having a sputtering surface, wherein the Ag sputtering target has three-dimensional fluctuation of grain sizes not more than 18%; and wherein the three-dimensional fluctuation of the grain sizes is measured by: exposing a plurality of layers having additional sputtering surfaces by slicing the Ag sputtering target in planes parallel to a sputtering starting surface, selecting a plurality of locations on each of the exposed sputtering surfaces of the layers, and measuring grain sizes D at all the selected locations of all the exposed sputtering surfaces of the layers by executing i) to iv) below, i) taking an optical micrograph of the selected location, ii) drawing a plurality of straight lines equal to or more than four in a grid pattern on the obtained micrograph, iii) investigating a number n of grain boundaries on each of the straight lines, and calculating a grain size d (unit: μm) for each of the straight lines on the basis of the following formula: d=L /( n·m ) wherein L: length of the straight line, n: number of the grain boundaries on the straight line, m: magnification of the optical micrograph, and iv) calculating the grain size D at the selected location as an average value of the grain sizes d for the plurality of straight lines; calculating values A 1 and B 1 using the formula below and based on the results of measurement of the grain sizes D at all the selected locations of all the exposed sputtering surfaces: A 1=( D max− D ave)/ D ave×100(%) B 1=( D ave− D min)/ D ave×100(%) wherein Dmax: maximum value among the grain sizes D at all the selected locations Dmin: minimum value among the grain sizes D at all the selected locations Dave: average value of the grain sizes D at all the selected locations; and selecting larger one of the values A 1 and B 1 as the three-dimensional fluctuation of the grain sizes.