| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a junction with excellent heat resistance and thermal fatigue properties using a soldering material including no lead, to join a wiring conductor to a surface electrode of a semiconductor element, and to join the semiconductor element to a conductor substrate at a high position accuracy. <P>SOLUTION: A soldering paste of an Sn3.5Ag0.5Cu particle (melting temperature: 220°C) is coated on the surface of the conductor substrate 12, and the semiconductor element 14 is placed on it. A cream solder of an Sn20Ag5Cu particle (temperature of solidus line: 220°C, temperature of liquidus line: 345°C) is coated on the surface electrode of the semiconductor element 14 and the wiring conductor 16 is placed on it. It is heated up to 250°C under the state, the soldering paste of the Sn3.5Ag0.5Cu particle is molten, and the cream solder of the Sn20Ag5Cu particle becomes in a solid-liquid coexistence. It is cooled, and the conductor substrate 12, the semiconductor element 14 and the wiring conductor 16 are joined through the Sn3.5Ag0.5Cu joining member 17 and the Sn20Ag5Cu joining member 15. <P>COPYRIGHT: (C)2007,JPO&INPIT |
