| 摘要 |
PROBLEM TO BE SOLVED: To solve the problems that characteristics of a solder paste changes due to reaction between an alloy and an activator in a flux during storage of the solder paste, the solder paste undergoing change in the characteristics is no longer suitable for printing use, voids can be formed due to gasification of the activator remaining after melting of the alloy, and electrical reliability is lowered due to the activator remaining in the residual. SOLUTION: A hydrotalcite is added in the flux to be used for the solder paste. The hydrotalcite can intercalate the anionic activator in a layered main skeleton so that the activator cannot react to the alloy during storage period of the solder paste. Thus, the solder paste is excellent in preservability and stability for printing. Furthermore, the activator is released from the main skeleton by heating and performs a function as the activator. Then the activator is intercalated again during solidification of the alloy so that generation of the void can be suppressed and the electrical reliability can be maintained even if the activator remains in the residues. COPYRIGHT: (C)2008,JPO&INPIT
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