Abstract: A system for determining surface profiles of specimens such as semiconductor wafers and for making linewidth measurements thereon includes a drive for mounting the wafer for oscillatory movement along a line and an optical imaging system overlying the wafer for focusing a beam on a small spot on the wafer and including a photodetector for detecting the reflected spot from the wafer. The spot is scanned along the line on the wafer while the focal depth of the imaging system is progressively changed while the photodetector and connected digital circuitry generate a plurality of spaced output signals for each scan along the line so that data comprised of a series of spaced signals are provided at a plurality of focus levels extending through the surface profile of the wafer. Computer means are provided for analyzing the data and providing a graphical output of the surface profile from which accurate linewidth measurements are made.

Abstract: A semiconductor wafer scanning system includes a confocal optical imaging system with a laser beam being focused on a small spot on the wafer surface to be scanned. The optics include an objective lens located closest to the wafer with means being provided to vary the spacing of the lens from the wafer over small distances to thus change the focal plane of the system. The wafer may be independently driven in two orthogonal directions in a plane generally perpendicular to the imaging system to bring selected portions thereof into view of the optics. During scanning, the wafer is rapidly vibrated in one of the directions while it is slowly moved in the other direction with a series of digital output signals being provided by the light reflected back from the laser spot on the moving wafer to provide precise information for constructing a three dimensional representation of the surface pattern of the wafer.

Abstract: This invention relates to aminoalkylphenoxyalkyl substituted heterocycles. These compounds antagonize the action of histamine on histamine H.sub.2 -receptors in the brain. A compound of the invention is 2-[3-[3-(piperidinomethyl)phenoxy]propylamino]benzthiazole.

Abstract: A confocal optical imaging system includes a laser for producing a linearly polarized beam which is transmitted through the optical elements of the system, focused on a small spot on the target, and reflected back through the optical elements to a photodetector where the reflectance from the spot is determined. The optical elements include a pinhole plate for restricting the size of the transmitted and reflected beams which plate, along with other of the optical elements, can produce unwanted reflections adding optical noise to the reflected beam from the target. A retardation plate between the pinhole plate and the target alters the polarization of the transmitted beam relative to the reflected beam so that a polarizer will discriminate between the true reflected beam signal and the unwanted reflections to thereby improve the signal-to-noise ratio at the photodetector.

Abstract: The invention comprises a compact substantially frictionless positioning device for guiding the motion of an object accurately along one or two axes. The object is supported on a pair of parallel motion solid hinges disposed either side of the axis of motion, each hinge comprising two flexible arms disposed in one plane. Springs are provided at one end of each hinge arm to permit the movement of the object along the axis and to restore it to its rest position when the displacing force is removed. Preferably the hinge arms and the springs are of rectangular cross-section to confine the motion of the object to one plane without the need for additional guides. The displacing force may conveniently be provided by an electromagnetic drive motor, the stator of which may be mounted on a further double parallel motion solid hinge assembly to minimize the change in the center of gravity which would otherwise occur when the object is displaced.

Abstract: Dark field viewing apparatus comprises either (a) a source of coherent plane wave radiation and focused coherent receiving means, or (b) a source of focused coherent radiation and a coherent receiver of plane wave radiation, the source and receiver being axially aligned in both cases; and elimination means to eliminate any radiation which in the region of the focus would travel substantially parallel to the axis of the apparatus. The apparatus may be a transmission or a reflection scanning acoustic microscope or a holographic recording system, and the elimination means may be a small acoustically-absorbent stop.