Method of producing tin emitted low alpha radiation by using vacuum refining

摘要

A method of producing a purified tin, which emits low alpha radiation by using a vacuum refining has developed: the steps are comprising: preparing a crude tin; containing the crude tin in a crucible and placing it in a vacuum furnace; and removing the impurities, which have higher vapor pressures and low boiling points than that of the tin from the vacuum furnace. The impurities, such as a lead and bismuth can be removed as much as possible by utilizing the difference of the vapor pressure of the elements in the tin. It is possible to minimize the emission of alpha radiation, so that it can be prevented the occurrence of the software errors.

主权项

1. A method of producing a tin, which emits low alpha radiation, by using a vacuum refining, the method is comprised of steps of:
(A) preparing a crude tin (S110); (B) containing said crude tin in a crucible and placing it in a vacuum furnace (S150), and (C) removing impurities, which have higher vapor pressures and lower boiling points than that of the crude tin from the vacuum furnace (S160), wherein the removing step is further consisting of supplying steam to said vacuum furnace at a temperature 1000° C.˜4300° C., at a pressure 0.01˜30 millitorr and for 2-6 hours to remove the impurities from said crude tin for obtaining a purified tin.