| 摘要 |
PROBLEM TO BE SOLVED: To provide an LSI soldered part abnormal joint detecting method allowing a soldered joint condition to be monitored in any time during operation of LSI and an abnormal joint to be detected in its early stages. SOLUTION: Joint checking solder balls 3, 4 are arranged in optional positions in the outermost circumference part of BGA 1, which is considered to have a short soldered joint lifetime theoretically because of application of the highest mechanical stress, and electrically connected to PWB 8 by means of solder. The joint checking solder ball 3 is electrically connected to the GND, and connected to the joint checking solder ball 4 via LSI internal wiring 2. The joint checking solder ball 4 is pulled up by means of a resistor 9 so as to be connected to one end (+) of a comparator 10. A reference power source Vref is connected to the other end (-) of the comparator 10. The output of the comparator 10 is connected to a soldered joint part monitoring part 11 detecting abnormal joint between the soldered joint parts 7a, 7b, and an output of the joint part monitoring part 11 is connected to a device control unit 12.
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