| 摘要 |
An apparatus and system for measuring the linewidths on masks and wafers utilizing a photodevice having a slit of predetermined dimension by moving the photodevice along the circumference of a circle whose center is coincident with the exit pupil of a microscope eyepiece. The photodevice and slit are moved through a predetermined radius (whose center coincides with the exit pupil) by means of a lead screw under the actuation of a reversible drive motor by way of a potentiometer interposed between the lead screw and the motor. The electrical resistance of the potentiometer, at any point thereof, is directly proportional to the linear position of the slit with respect to the projected image. The electrical resistance of the potentiometer is converted to a voltage value and is displayed, in arbitrary units, on a digital voltmeter. A trigger circuit controls the circuit display from the potentiometer so that the dimension from the leading edge to the trailing edge of a linewidth is displayed without any human judgment. Thus, by monitoring and controlling the digital display from the potentiometer in response to the output of the photodevice, the voltage read-out is proportional to the actual width of the line on the mask or wafer.
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