Abstract: A method is provided for determining the magnitude of flatness deviation in high density information discs, such as video discs, manifesting irregularities in playback. Such flatness deviations are known as "orange-peel." A stylus riding over a relatively large area (4-5 grooves) of the disc surface provides a vertical velocity signal within a given spatial or temporal frequency band. The signal in velocity or displacement form is the quantitative measure of deviation. The method is useful for other type discs where quantitative measurements in flatness deviation are desired.
Abstract: An optical profilometer for surface contours subject to tilt is optically scanned to measure the surface contours. Surface tilt effects are obviated by slitted apertures in the paths of the reflection beams to pass the beams with large surface tilts (on the order of 30.degree.) without loss of sensitivity, accuracy, or precision.
Abstract: Apparatus for flood exposing deep ultraviolet (DUV) photoresist material from a xenon lamp source providing pulsed radiation in the DUV range formed into an annular beam by a paraboloid reflector. The radiation beam is substantially collimated with a preferred divergence of 4.degree. for mask (imaging) development. Wafers having single-layer or multi-layer photoresist material sensitive to UV radiation are flood exposed to achieve, with high resolution, imaging, even if the photoresist layers are thin. The apparatus is also used to cure DUV-sensitive photoresist material with the radiation beam having the same or preferably greater divergence. The photoresist material is flood exposed for either imaging or curing that is both rapid and uniform.
Abstract: The presence of crystallographic damage in a semiconductor surface region is determined by surface photovoltage (SPV) measurements. Deviations from the idealized straight line SPV plot of photon flux (I.sub.o) versus reciprocal absorption coefficient (.alpha..sup.-1) in upward-facing concave form are used as a criterion of surface quality. This criterion is used to determine the minimum etching required to remove the damaged surface.
Abstract: A method and apparatus for aligning a surface of a pyramidal-shaped workpiece (such as a stylus) with respect to a positioning ring attached to a holder supporting the workpiece. One surface of the workpiece (electrode of the stylus) is exposed to an incident light beam of large diameter so that only a portion of the incident beam is reflected from the surface onto a calibrated screen. A mirror reflects the remaining portion of the light beam back to the other two stylus surfaces to provide a pair of reflected beams onto the same screen. The workpiece is rotated to position the three reflections on the calibrated screen for comparison to a standard.
Abstract: A method for positioning a diamond stone in an indented shank is described. A wetting agent put in contact with a diamond draws it upwardly into the indentation in the shank. A brazing material is added to the wetting agent to be drawn into the interface between the diamond and the shank indentation. After drying the wetting agent from the assembly, a laser beam heating the shank effects a strong, acid resistant braze of the shank and diamond. A novel brazing material in weight percent of 71% silver, 28% copper, 0.75% nickel, with 0.25 to 0.35% in the aggregate of any one or more of ruthenium, rhodium or iridium provides a strong bond with significant acid resistance.
Abstract: An ion implantation apparatus and method are disclosed for reducing contamination of doubly-charged ions by singly-charged ions. A liner, with a grooved or smooth surface, formed of beryllium or graphite reduces secondary electron scattering into the ion beam. Solid red phosphorus reduces the operating vacuum thereby reducing contamination.
Abstract: A thickness monitor useful in deposition or etching reactor systems comprising a crystal-controlled oscillator in which the crystal is deposited or etched to change the frequency of the oscillator. The crystal rests within a thermally conductive metallic housing and arranged to be temperature controlled. Electrode contacts are made to the surface primarily by gravity force such that the crystal is substantially free of stress otherwise induced by high temperature.
Abstract: Cleaning apparatus for cleaning semiconductor wafers and the like in a chamber of cleaning fluid vibrating at ultrasonic (megasonic) frequencies utilizing an electrically energized transducer, such as a piezoelectric crystal, mounted on a conductive foil formed of tantalum or zirconium. Pinholes or other ruptures in the foil can cause high energy arcs capable of exploding vapors of inflammable solvents. The foil carrying the transducers is isolated from the cleaning fluid vapors by a closed buffer chamber containing an inert liquid that couples vibratory energy to the cleaning fluid and another closed chamber enclosing the transducers. Accordingly, cleaning fluids, such as the acetones, alcohols and ketones, heretofore considered hazardous fluids, can be used in the apparatus.
Abstract: Topographical defect detecting apparatus and process for optically inspecting a circular or spiral track surface defining a diffraction grating such as exists on a video disc or optical disc record. Light from a substantially point source illuminates the track surface. Diffracted reflections from the surface are viewed by the human eye with or without the aid of a TV camera and monitor.Non-uniformities in track spacing and deviation from average surface flatness are readily observable.
April 15, 1983
Date of Patent:
September 17, 1985
Horatio N. Crooks, Martin J. Kelly, Jr.
Abstract: A method of determining the crystalline or structural quality of phase transformable material such as silicon uses light scattering. The material is exposed to a beam of light of a selected wavelength. Scattered light having an intensity above a threshold is detected to provide a signal which is used to control the intensity of a display beam of a visual display device. The threshold is varied to thereby vary the display beam intensity so as to provide the minimum intensity of display beam which yields a full display. The value of the thusly adjusted threshold intensity is used as a direct measure of the structural quality of the material.The light scattering process is used to determine the phase of deposited material.A layer of silicon material annealed from as-deposited amorphous phase material is easily and quickly distinguished from material as-deposited crystalline phase material and subsequently annealed.
Abstract: A system for positioning a body having two opposed edges and having a first axis oriented to pass through the two edges. A beam of light oriented along a second axis orthogonal to the first axis images one or both of the edges onto all or a portion of a photodetector array which is aligned in a direction parallel to the first axis. The array is scanned to obtain a light intensity transition profile of all or part of the projected image whereby the profile has either one or two 50% intensity points. The body is then shifted until both of the 50% intensity points strike predetermined locations on the array indicating that both the edges are included in the image. The body is shifted along the first axis until the fifty percent (50%) intensity point along the transition profile strikes a predetermined location along the photodetector array. The body is also moved along the second axis until the slope of the intensity transition profile is maximized, thereby obtaining an in-focus position.
Abstract: A semiconductor device having a rectifying junction after passivation is exposed to a humid ambient while being tested for humidity-induced leakage currents indicative of passivant defects such as pinholes, cracks, etc. The amplitude of the reverse biased humidity-induced current is indicative of the integrity of the passivant coverage.
Abstract: This disclosure describes an optical reflectance method for rapid and simultaneous determination of surface roughness and structure of silicon films deposited by chemical vapor deposition. The magnitude of the reflectance of polycrystalline silicon films at a wavelength of about 280 nm can be used directly as a quantitative measure of film surface roughness. The magnitude of the reflectance of as-deposited amorphous or mixed amorphous-polycrystalline silicon films at a wavelength of about 400 nm can be used as a measure of the combined surface roughness and amorphism of the films. Other materials such as metals, alloys and silicides used in semiconductor technology may be evaluated with respect to surface roughness in a similar manner.
Abstract: A method of treating the surface of a sample of n-type silicon material in preparation for measurements for determining the minority carrier diffusion length of the material by the surface photovoltage method comprises applying a strong oxidizing agent to an appropriately prepared surface of a semiconductor material such as silicon. The oxidizing agent is taken from the group consisting of potassium permanganate [KMnO.sub.4 ], potassium dichromate [K.sub.2 Cr.sub.2 O.sub.7 ], and ammonium dichromate [(NH.sub.4).sub.2 Cr.sub.2 O.sub.7 ]. The surface preparation assures a consistently large surface photovoltage that is stable during the surface photovoltage measurement for minority carrier diffusion length.
Abstract: A mechanical scriber using a scribing tip, such as a diamond, provides controlled scriber forces with a spring-loaded compound lever arrangement. The scribing force and range of scribing depth are adjusted by a pair of adjustable micrometer heads. A semiconductor device, such as a multilayer solar cell, can be formed into scribed strips at each layer.
Abstract: An apparatus for chemically vapor-depositing silicon material on surfaces of a plurality of substrates arranged in a stack that is continuously rotating. A gas distributor formed of a pair of coaxially tubes, in fixed relation with the rotating substrates, provides a pair of gas streams from a pair of parallel slots extending lengthwise of the tube facing the substrates. Gas input through the inner tube is passed through holes conducting gas from the inner tube to the outer tube and into the chamber as two gas streams. Substantially uniform deposition is achieved within .+-.5% with gas high deposition rates effected by high flow gas streams that are not turbulent.
Abstract: A device for monitoring gap deviations in an optical printer comprises a mask having a plurality of closely-spaced differently-sized apertures. Actinic light passing through the aperture to a photoresist surface develops a pattern of diffraction-induced images in the photoresist surface. Each image is uniquely shaped according to its associated aperture size, gap dimension, light wavelength and photoresist characteristics. An indexing parameter (.DELTA..nu.) is used to relate the pattern of images developed to gapping or focusing deviations in the system. Either proximity or projection printers can be used.
Abstract: Crystalline quality of a semiconductor material at its interface with an insulator is optically evaluated by a reflected light beam scanned in wavelength. The refractive index of the material at or near the interface is determined by calculation from the measured values of reflectivity extrema and compared, if desired, to the bulk refractive index of the material. This index is an indicia of the crystalline quality at the interface.
Abstract: A keel-tipped stylus for playback of video information from a disc record is formed on a lapping disc having a spiral signal track on the land between a spiral lapping groove. The respective pitches of the signal track and groove are different whereby the signal track and lapping groove cross each other. A playback stylus riding in the groove will detect a signal from the track to monitor the lapping process.