| 摘要 |
PURPOSE:To obtain a highly reliable multilayer printed wiring board by easily and adequately soldering the interior of a through hole connecting multilayer printed wiring circuits and the easily fixing each layer. CONSTITUTION:Diameters of through holes 11, 12 bored on the upper and lower printed wiring boards 30, 40 forming the printed wiring circuits to the front and rear surfaces of the substrates 1, 2 are set so that the diameter of the hole of the upper printed wiring board 30 is smaller than that of the lower printed wiring board 40. Moreover, the printed wiring boards 30, 40 are laminated, allowing provision of a spacer 21 at the interface other than the connecting lands 8, 9 and keeping a little clearance between the connecting lands 8, 9 and are then fixed with a plurality of screws. Moreover, after a plurality of fine leads 20 are inserted into the through holes 11, 12 of the laminated printed wiring board 50, the through holes 11, 12 are filled the solder 13 utilizing the capillary tube phenomenon of the fine lead 20 and the surfaces of the connecting lands 7, 8, 9, 10 are soldered to form a multilayer printed wiring board 50. |
