| 摘要 |
PURPOSE:To easily detect any defective power supply leakage due to floating node by a method wherein a part of diffused layer of a circuit pattern formed on the surface of a chip of a semiconductor integrated circuit is photoirradiated to detect a leakage current while shifting the photoirradiated positions. CONSTITUTION:A whole chip is theoretically divided into multiple blocks assuming a size corresponding to a photoirradiated space on the chip surface of a device under testing (DUT) 3 as one block. Next, the DUT 3 is impressed with a power supply voltage and an input pattern by a pattern generator 6 and a DC measuring unit 7 to set up a power supply leakage in the measurable state. The power supply leakage is measured by means of irradiating respective blocks by command of a controller 8 to record measured values of power supply leakage and positions of blocks. If there is any block wherein the measured values of power supply leakage are fluctuated by photoirradiation, it may be estimated that a floating node exists in a circuit of the block. Through these procedures, the time required for trouble shooting can be cut down.
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