| 摘要 |
PURPOSE:To prevent occurrences of defective soldering by providing each metal piece that is superior in thermal conductivity and soldering properties in a manner that its metal piece passes through a connection land to reach the opposite side of a printed wiring board. CONSTITUTION:As a remedy for a partial temperature difference produced transiently, the difference between a temperature produced in a terminal 2 transiently and that of each connection land 4 is removed by increasing the heat received in the connection land 4. In other words, each metal piece 5 which is superior in thermal conductivity and soldering properties, for example, a short copper wire that is covered with solder and the like is provided in each connection land 4 after making it pass through up to the rear of the connection land 4. When it is used, the end surface of each metal piece 5 that is provided after passing through the rear of a printed wiring board 3 is heated and its heat is fed to the connection land 4 through the metal piece 5. Receiving more heat than that received by a conventional connection land, each connection land is heated, and then the temperature difference between the temperature of the above connection land and that of each terminal 2 produced transiently is lessened and the development of wicking phenomenon in soldering is suppressed fully. In the same manner, even a Manhattan phenomenon, relief and slippage phenomena and the like which are caused by the temperature difference between a pair of terminals 2 are suppressed by decreasing transient temperature difference even with respect to chip-type components. |
