A method and apparatus for soldering electronic, surface compositions, especially with components populated circuit boards

摘要

During the pickling process in the novel method of soldering electronic printed circuit boards, in particular component-carrying printed circuit boards, a condensable auxiliary substance, for example water, is first adsorbed in defects in the oxide layers on the solder connection pads and at least partly condensed in the defects. The oxide layers are then subjected to such fast heating that the auxiliary substance condensed in the defects explosively evaporates and consequently breaks up the oxide layer, which detaches itself from the metallic base material in such a way that the solder connection pads are converted to a virgin state for the subsequent soldering process itself. In the case of wave soldering, the fast heating is preferably carried out by the solder wave itself. If nonoxidic passive layers have also to be removed by pickling, this is preferably done in a preceding step in the pickling process, during which the oxide layer is rendered hydrophilic. A plasma pretreatment is suitable for this purpose. The novel apparatus has a moistening chamber in which the condensable auxiliary substance is presented to the hydrophilic oxide layers and is adsorbed by the latter. …IMAGE…