| 摘要 |
PURPOSE:To prevent of the parasitic capacitance of a pad for a needle pad from affecting normal operation by connecting the pad connected to an internal circuit and the internal circuit through a gate and transmitting a control signal turning the gate ON-OFF over the gate. CONSTITUTION:FETs 7 operated as gates are each formed among respective metallic wiring 3 for an internal circuit and metallic pads 4 for needle pads shaped in response to these metallic wirings. A control signal being at an 'H' level at the time of the signal measurement of the internal circuit and being at an 'L' level in other cases is applied to the gate 12 for the FET 7. The gate potential of the FET 7 is brought to the 'L' level and the FET 7 is kept under the state of cut-off on the normal operation of the internal circuit except the time of signal measurement, and the metallic wirings 3 for the internal circuit and the metallic pads 4 for the needle pads corresponding to the metallic wirings 3 are cut off. Accordingly, the parasitic capacitance of the metallic pad 4 side for the needle pad is detached completely from the internal circuit, and has no effect on the normal operation of the internal circuit.
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