High purity tin and method for manufacturing same
View Patent ↗Provided is a high purity tin (Sn) having an extremely low oxygen content. A high purity tin having a tin purity of 5N (99.999% by mass, provided that carbon, nitrogen, oxygen and hydrogen are excluded) or more, wherein the high purity tin has an oxygen content of less than 10 ppb by mass, as measured by elemental analysis using Dynamic-SIMS.
1. A method for manufacturing a high purity tin, comprising subjecting tin having a purity of 3N (99.9% by mass, provided that carbon, nitrogen, oxygen and hydrogen are excluded) or more, and having an oxygen content of 5 ppm by mass or more and a carbon content of 10 ppm by mass or more as measured by elemental analysis using a nondispersive infrared absorption method, to a vacuum heating treatment until the oxygen content in the tin is decreased to be less than 10 ppb by mass as measured by elemental analysis using Dynamic-SIMS.
2. The method according to claim 1 , wherein the vacuum heating treatment is carried out at a temperature of 400° C. or more and a degree of vacuum higher than 1×10 −3 Pa (absolute pressure).
3. The method according to claim 1 , wherein the vacuum heating treatment is carried out for 3 hours or more.
4. The method according to claim 1 , further comprising electrolytically refining a raw material tin using an electrolytic solution containing at least one carbon-containing compound to obtain the tin having the purity of 3N (99.9% by mass, provided that carbon, nitrogen, oxygen and hydrogen are excluded) or more, and having the oxygen content of 5 ppm by mass or more and the carbon content of 10 ppm by mass or more as measured by elemental analysis using the nondispersive infrared absorption method, wherein the raw material tin has a purity of 3N (99.9% by mass, provided that carbon, nitrogen, oxygen and hydrogen are excluded) or more, and has an oxygen content of 5 ppm by mass or more and a carbon content of less than 10 ppm by mass, as measured by elemental analysis using a nondispersive infrared absorption method.
5. The method according to claim 4 , wherein the at least one carbon-containing compound is a leveling agent.
6. The method according to claim 1 , further comprising adding elemental carbon to a raw material tin to obtain the tin having the purity of 3N (99.9% by mass, provided that carbon, nitrogen, oxygen and hydrogen are excluded) or more, and having the oxygen content of 5 ppm by mass or more and the carbon content of 10 ppm by mass or more as measured by elemental analysis using the nondispersive infrared absorption method, wherein the raw material tin has a purity of 3N (99.9% by mass, provided that carbon, nitrogen, oxygen and hydrogen are excluded) or more, and has an oxygen content of 5 ppm by mass or more and a carbon content of less than 10 ppm by mass, as measured by elemental analysis using a nondispersive infrared absorption method.
7. The method according to claim 1 , wherein carbon atom is present at a ratio of 1 mole or more and 500 mole or less per 1 mole of oxygen atom in the tin having the purity of 3N (99.9% by mass, provided that carbon, nitrogen, oxygen and hydrogen are excluded) or more, and having the oxygen content of 5 ppm by mass or more and the carbon content of 10 ppm by mass or more as measured by elemental analysis using the nondispersive infrared absorption method.
8. The method according to claim 1 , wherein carbon atom is present at a ratio of 50 mole or more and 100 mole or less per 1 mole of oxygen atom in the tin having the purity of 3N (99.9% by mass, provided that carbon, nitrogen, oxygen and hydrogen are excluded) or more, and having the oxygen content of 5 ppm by mass or more and the carbon content of 10 ppm by mass or more as measured by elemental analysis using the nondispersive infrared absorption method.