| abstract |
In order to connect components to printed circuit boards, the connections of the components are soldered to connecting surfaces on the printed circuit board. In the course of the reduction in size of the components, soldering methods have been modified in order to take account of the smaller dimensions of the connections, the smaller distances between them and the reduced thermal insulation of the semiconductor substrate. The laser soldering method has been proven, in particular, in the case of which the laser beam is moved to the solder points individually and the heat energy required for melting is supplied by the laser beam. However, this method has the disadvantage that it takes a relatively long time for all the connections to be soldered and not all the connections of a component can reach the melting temperature simultaneously. The invention provides a remedy for this in that the solder points are heated by a fuel which is added to the solder paste or is applied onto it. In this case, the excitation energy to ignite the fuel is transmitted by a laser beam. However, since the rest of the heat energy is produced by the fuel, the laser beam can immediately be moved to the next solder point once the fuel has been ignited, and the process can be repeated there. In consequence, the rate of soldering can be increased by a factor of approximately 50. |