SOLDERING OF PRINTED-CIRCUIT BOARD

PURPOSE:To prevent the occurrence of a void by a method wherein, after a creamy solder has been melted by heating a printed-circuit board and has been cooled and solidified, an adhesive sheet is stripped and a chip component and the printed-circuit board are soldered. CONSTITUTION:A creamy solder 3 is coated on an adhesive face 2 of a heat- resisting adhesive sheet 1. A chip component 6 to be mounted on a printed- circuit board 4 is placed on a part where the creamy solder is coated and which corresponds to a position to be mounted. The printed-circuit board 4 and the adhesive sheet 1 are put together; the printed-circuit board 4 excluding the part of the chip component 6 and the adhesive sheet are pasted together. The whole assembly is heated by using an appropriate heating device in such a way that the printed-circuit board 4 is situated at the lower part and that the adhesive sheet 1 is situated at the upper part; the creamy solder is melted. The molten solder flows down along the side of an electrode 7 by following a flux and enters a gap between the chip component 6 and the printed-circuit board 4 due to a capillary phenomenon. Accordingly, a void due to the remaining flux is not caused. After the solder has been solidified completely, the adhesive sheet 1 is stripped from the printed-circuit board 4.