| 摘要 |
PROBLEM TO BE SOLVED: To reduce alpha rays emitted from a solder bump and reduce the soft error inversion ratio of a semiconductor device, by causing a solder alloy to be an alloy of Sn and Bi or an element having a specified atomic number and not related with specified alpha decay. SOLUTION: A solder bump 12 is formed on a pad electrode of a semiconductor substrate 10 by a plating method and a solder ball, thus forming a semiconductor device 14. A solder alloy is caused to be an alloy of Sn and Bi or an element having an atomic number smaller than 81 and not related with alpha decay. Among elements having atomic numbers smaller than the atomic number 82 of Pb, there exists no element related with decay series, such as, U and Th. Therefore, no alpha decay is generated and hence no alpha ray is emitted. Thus, the soft error inversion ratio of the semiconductor device 14 may be reduced. Also, by reducing the quantity of alpha rays emitted from the solder alloy, the solder bump 12 may be arranged in a matrix. Therefore, finer pad diameter and pitch size of the bump are not necessary and deterioration in fatigue life of the solder bump 12 may be prevented. |
