High purity tin and tin alloy are provided in which the respective contents of U and Th are 5 ppb or less, the respective contents of Pb and Bi are 1 ppm or less, and the purity is 5N or higher, provided that this excludes the gas components of O, C, N, H, S and P. A cast ingot of the tin or alloy has an α ray count of 0.001 cph/cm² or less. Since recent semiconductor devices are densified and of large capacity, there is risk of a soft error occurring due to α ray from materials in the vicinity of the semiconductor chip. Thus, there are demands for purifying soldering material used in the vicinity of semiconductor devices, and materials with fewer α rays. The disclosed tin, alloy, and method reduce α dose of tin so as to be adaptable as the foregoing material.

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