| 摘要 |
PURPOSE:To enable the tentative fixing of a package to an insulating board by a method wherein heating pads are provided on the insulating board, on which connection pads joined to the solder bumps of the package are arranged, so as to be located outside the outer shape of the package, and the heating pads and the connection pads are connected together with heat transfer patterns provided with a solder dam on their surfaces. CONSTITUTION:A printed circuit board is formed in such a structure that connection pads 3-1 are formed at positions in matrix on the primary face of an insulating board 2 so as to be opposed to the solder bumps of a package, heating pads 14 are provided close to the connection pads 3-1, for instance, located at the four corners of foot patterns 3, and the heating pads 14 and the connection pads 3-1 tentatively fixed to the solder bumps are connected together through a heat transfer pattern 15 which is excellent in thermal conductivity and provided with a solder dam that prevents molten solder on the connection pad 3-1 from flowing to the heating pad 14. When the heating pads 14 are heated as making the connection pads the solder bumps 1-1 bear against the connection pads 3-1, the connection pads 3-1 rise in temperature by the heat transfer pattern 15 and the solder bumps 1-1 which bear against the connection pads 3-1 are fused and they are joined together. At this point, self- alignment is made and the relative position of a connection pad to a solder pad is corrected and they are tentatively fixed together. |
