Abstract: A positioning system is provided for positioning a part or element in different inclinations relative to a plane normal to a central axis, and for also rotating the part about the central axis. A holder supporting the part is freely pivotable about a point on the central axis. A central spindle on the axis is coupled to a concentric tiltable ring assembly that is controllable in two directions of freedom from an input device. The tilt and rotational motions of the ring assembly are translated to the part holder by a multi-element linkage mechanism having low friction bearings at each end and allowing a wide range of motion. The part may be a semiconductor wafer to be inspected for flaws on a holder comprising a vacuum chuck. Alternatively the tiltable, rotatable mechanism may be used to support an optical camera or viewing device, or a robotic mechanism, for operation within a wide field.

Abstract: 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.