ELECTRONIC DEVICE

摘要

PROBLEM TO BE SOLVED: To suppress deterioration in a protection film caused after solder reflow in an electronic device wherein the surface of a metallic wire layer formed on one side of a substrate is covered by an insulating protection film and the metallic wire layer and a solder bump are joined through an opening formed to the protection film.

SOLUTION: The metallic wire layer 20 has at its uppermost layer an Au layer 22 made of Au with which an alloy can be formed with an Sn component being a component of the solder bump 40, the Sn component being diffused by heat produced at the solder reflow. Adopting a configuration of the film thickness of the Au layer 22 selected to be 0.01μm or over and 0.1μm or below can suppress growing of an Au-Sn alloy layer 52 resulting from diffusion of the Sn being the component of the solder bump into the Au layer 22 placed under the protection film 30 during the solder reflow.

COPYRIGHT: (C)2004,JPO