METHOD OF MANUFACTURING SEMICONDUCTOR MODULE

PROBLEM TO BE SOLVED: To provide the method of manufacturing a semiconductor module having a temperature hierarchy connection in which the defect of a void is reduced and the connection reliability of a high temperature side connection portion is maintained even in the case where the soldering of a lead-free solder material is carried out in the air. SOLUTION: There is provided the method of manufacturing an electron device comprising an electron component, a first substrate on which the electron component is mounted, and a second substrate on which the first substrate is mounted. The method comprises the first step of connecting the electrode of the electron component and the electrode of the first substrate by reflowing first lead-free solder which has a metal ball whose melting point is higher than those of an Sn solder ball and the Sn solder at temperature equal to or more than 240°C and equal to or less than the heat-resistant temperature of the electron component and in which the metal ball is covered with an Ni layer and the Ni layer is covered with an Au layer, and the second step of connecting the first substrate on which the electron component is mounted and the second substrate by reflowing second lead-free solder at temperature lower than a reflow temperature in the first step. COPYRIGHT: (C)2008,JPO&INPIT