HIGH-PURITY TIN OR TIN ALLOY AND PROCESS FOR PRODUCING HIGH-PURITY TIN

摘要

Provided is high purity tin or tin alloy wherein the respective contents of U and Th are 5ppb 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). This high purity tin or tin alloy is characterized in that the ± ray count of high purity tin having a cast structure is 0.001 cph/cm 2 or less. Since recent semiconductor devices are densified and are of large capacity, there is considerable risk of a soft error occurring due to the influence of the ± ray from materials in the vicinity of the semiconductor chip. In particular, there are strong demands for purifying the soldering material or tin to be used in the vicinity of semiconductor devices, as well as for materials with fewer ± rays. Thus, the present invention aims to provide high purity tin or tin alloy and the manufacturing method of such high purity tin by reducing the ± dose of tin so as to be adaptable as the foregoing material.