| 摘要 |
PURPOSE:To enable terminals of a hybrid integrated circuit to be mounted without any damage even if thermal history such as heat cycle is repeated with the terminals having improved resistance against high temperature by using a solder material used for mounting the terminals to materials with a large growth for the lower-surface side of the printed-circuit board at the upper-surface mounting side of the printed-circuit board. CONSTITUTION:When joining a circuit pattern at the upper part of a substrate and a circuit pattern at the lower part of the substrate through a terminal pin 3, a high-temperature solder with a higher fluxing temperature than that of a eutectic solder which is generally used used to join a mounting land 4 at the lower-surface side of the first layer and a mounting land 5 of a second-layer substrate. A metal pin constituting a terminal pin has a low linear coefficients of expansion, while a soldering part connecting the terminal pin and the substrate becomes a region which absorbs distortion accompanied by the amount of displacement. A soldering material with a large growth as compared with the lower-surface side of the substrate is used for the upper-surface side. It is possible to absorb the amount of displacement accompanied by increased and decreased temperature at the upper-surface side with increase growth. On the other hand, the lower-surface side has a high fluxing point, thus obtaining a terminal pin joining state without any breakdown at the solder-joined part. |
