| 摘要 |
PROBLEM TO BE SOLVED: To facilitate failure analysis by forming a specific in-circuit observing part, as an interconnection, on the uppermost layer and connecting the prestage and post-stage elements thereat electrically through the in-circuit observing part thereby locating malfunctions. SOLUTION: Electrical measurement is performed by probing an n-layer (uppermost layer) wiring 1b or blind vias 5a, 5b. The n-layer wiring 1b is cut at an in-circuit observing part where the cause of malfunctions is specified. Consequently, the blind vias 5a, 5b are disconnected electrically. Subsequently, the blind vias 5a, 5b are probed respectively and subjected, independently, to a desired electrical characteristic test, e.g. potential measurement, I-V characteristic test, or the like. Comparison is then made with characteristics at the time of normal operation thus making a decision whether the cause of malfunctions is present on the prestage element side or the post-stage element side or on both sides relative to the on-circuit observing part. |
