| abstract |
In flip chip attach of electronic components, underfill is filled between the component and the substrate to alleviate, for example, thermal stress. In electronic component mounting using copper pillars conducted so far, filler contained in the underfill may cause separation in the process of heating and curing the resin. Disclosed is plating the surfaces of the copper pillars with solder. Mobilization of the filler charged in the underfill due to electric fields produced by local cells that are developed upon contact between dissimilar metals, is suppressed, and occurrence of crack at connection portions is obviated. Thus, connection reliability is increased. |