| 摘要 |
A circuit board of the invention comprises: an insulating base, which has a semiconductor element mounting portion on an top or bottom side thereof, and on which wiring patterns led out of the semiconductor element mounting portion are installed; and a plurality of substantially circular terminal pads, which are formed on the bottom side of the insulating base, which are connected to the wiring patterns, and to which solder terminals will be joined, wherein each of the terminal pads is provided with a solder lead portion which projects from a center side toward a perimeter side of the insulating base in a diametrical direction of the terminal pad. A part of the solder terminal is pulled out at the solder lead portion, whereby it is possible to prevent a fatigue failure of a joint of the terminal pad and the solder terminal due to a concentration of thermal stress, to electrically connect the solder terminal to the terminal pad in a stable manner for a long time period.
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