Abstract: A method and apparatus are disclosed for evaluating relatively small periodic structures formed on semiconductor samples. In this approach, a light source generates a probe beam which is directed to the sample. In one preferred embodiment, an incoherent light source is used. A lens is used to focus the probe beam on the sample in a manner so that rays within the probe beam create a spread of angles of incidence. The size of the probe beam spot on the sample is larger than the spacing between the features of the periodic structure so some of the light is scattered from the structure. A detector is provided for monitoring the reflected and scattered light. The detector includes multiple detector elements arranged so that multiple output signals are generated simultaneously and correspond to multiple angles of incidence. The output signals are supplied to a processor which analyzes the signals according to a scattering model which permits evaluation of the geometry of the periodic structure.

Abstract: The present invention has a configuration in which a line confocal optical system is formed and plural times of illumination by lines of lights are carried out. Particularly, in the present invention, the diffraction grating 32 produces the m×n number of sub beams. Further, the m×n number of sub beams are deflected by the acoustic optical element 33 so that their irradiation areas are to be continuous. Therefore, since the beam carries out scanning using the m×n number of sub beams, scanning can be completed in a short time.

Abstract: Defects such as holes and bumps in the surface of a semiconductor wafer are detected by an optical inspection system that combines darkfield and brightfield illumination techniques. A single light stop, which forms part of the illumination system, includes a pair of openings configured to produce both a solid cone of light and a hollow of light which are simultaneously focused onto the wafer surface. The directly emanating light as well as the scattered light collected from the wafer surface produce a resultant image that is the product of darkfield and brightfield illumination. Modulation of the light beam and tilting of the light focused onto the wafer surface may be advantageously used to improved contrast and resolution of the viewed image.

Abstract: A method for plasma etching a shallow recess or shallow trench at a predetermined depth by illuminating a wafer with a light source and using a spectrometer to receive the light reflected from the wafer begins with a step of detecting an etch start time, either by detecting a time of plasma ignition, as extracted from reflectance data, or a time extracted from the reflectance data when a wafer reflectance signal is observed to begin to change after a residual layer is etched away prior to beginning a recess or trench etch. The next step is measuring a reflectance intensity of light reflected from the wafer. Preferably, a plasma background signal is removed from this measurement and an array detector is used wherein the wavelength is determined using the reflectance model. Next, an etch rate is determined by fitting data representing the collected reflectance signal to the wafer reflectance model as a function of time, and extracting the etch rate from the model.

Abstract: Systems and methods for determining the positions of the discs of a mechanical display by using the shadow cast on an optical array by a profiled cam arrangement.

Abstract: A method of determining thickness and refractive index of an optical thin film is described. The method includes generating a diagnostic light beam having a first and a second wavelength. The method also includes measuring unattenuated light intensities at the first and the second wavelength of the diagnostic light beam. The method also includes measuring attenuated light intensities at the first and the second wavelength of the diagnostic light beam after transmission through the optical thin film. A null light intensity for the diagnostic light beam at the first and second wavelength is also determined. A first and second normalized intensity function is determined using the measured unattenuated light intensities, the measured attenuated light intensities, and the measured null light intensities. The thickness and refractive index of the optical thin film is then determined by solving the first and second normalized intensity function for thickness and refractive index.

Abstract: An optical measuring device for measuring in a fiber optic network, comprises a measuring unit for performing the measurement in the fiber optic network, a processing unit for processing the measuring results from the measuring unit, and a display for visualizing the processed measuring results. The processing unit further receives imaging signals provided by an imaging unit and processes such imaging signals to be displayed by the display.

Abstract: Equipment for detecting impurities in transparent material comprising a light source to illuminate the material, a camera to detect light transmitted through the material and signal-processing apparatus for processing and analysing signals from the camera representing the light transmission through the material. This type of equipment is calibrated by dark areas being displayed on a film of transparent material (22, 24, 26) and the actual sizes (30) of the areas being determined. The sizes of the dark areas are then determined using the detecting equipment (34) and in this way determined sizes are compared with actual sizes (36) for calibration of the detecting equipment (38).

Abstract: The invention relates to a method and an arrangement for measuring the structure of an object. The structure is scanned by touch, by means of a scanning element whose position is optically detected. The force produced after the contact between the scanning element and the object is determined and optionally adjusted to constant values.

Abstract: A method for measuring the depth of a subject trench includes the steps of forming on a substrate a plurality of measurement trenches having different widths aj (ai<aj+1, i=1, 2, . . . , n) and a depth equal to the depth d0 of the subject trench, irradiating the measurement trenches with a parallel ray at an incidence angle of &thgr; with respect to the substrate surface while detecting the reflected ray from the substrate, separating the measurement trenches into a first group providing dark images and a second group providing bright images, and calculating a range for the depth d0 by using a largest width ak of the measurement trenches in the first group and a smallest width ak+1 of the measurement trenches in the second group based on the following relationship: (ak/2)tan &thgr;<d0≦(ak+1/2)tan &thgr;.

Abstract: An endoscope for inspection of an observation cavity, in particular of an observation cavity in which a hot medium and/or infrared radiation is present, has a shaft in which an optical system is arranged. The shaft has an inner shaft and an outer shaft surrounding the latter at a distance, the optical system being arranged in the inner shaft. The shaft is configured in the region of its distal end in such a way that it is substantially opaque to electromagnetic radiation in the infrared spectral range.

Abstract: A system and method for nondestructive detection of gas in a sealed container. The system includes a tunable diode laser source that provides a uncollimated laser beam for absorption in a substance to be measured, a detector that detects the laser beam, and a zone that accepts one or more of the selected containers. Each container is substantially optically transparent and may contain the substance to be measured. The zone is located between the detector and a laser source configured to transmit the laser beam through the zone. The invention also includes a collection lens that focuses the laser beam onto the detector, the collection lens being located between the zone and the detector.

Abstract: A high sensitivity and high throughput surface inspection system directs a focused beam of light at a grazing angle towards the surface to be inspected. Relative motion is caused between the beam and the surface so that the beam scans a scan path covering substantially the entire surface and light scattered along the path is collected for detecting anamolies. The scan path comprises a plurality of arrays of straight scan path segments. The focused beam of light illuminates an area of the surface between 5-15 microns in width and this system is capable of inspecting in excess of about 40 wafers per hour for 150 millimeter diameter wafers (6-inch wafers), in excess of about 20 wafers per hour for 200 millimeter diameter wafers (8-inch wafers) and in excess of about 10 wafers per hour for 300 millimeter diameter wafers (12-inch wafers).

Abstract: Flow separation detectors and, more particularly feedback sensor arrangements consisting of optical fiber tufts adapted to provide for the measurement of surface aerodynamic flow phenomena through the effects birefringence or transmitted light, and especially with regard to aerodynamic flow separation which is encountered over a surface. Also facilitated is the detection of aerodynamic flow separation with a concurrent detection of encountered mechanical strain and stresses on the surface structure being monitored.

Abstract: The quality of distribution of pigments in a matrix is estimated by measuring the reflectivity of a sample of the pigmented matrix at a shorter and a longer wavelength, and calculating a function of the two measurements. A ratio of the normalized reflectivity for broad short and long wavelength bands is the preferred function.

Abstract: An optical metrology system for measuring a contour of a workpiece surface. The system includes a multi-wavelength light projector that projects a wavelength-varying collimated light beam onto the surface of the workpiece. The collimated light beam has a plurality of substantially parallel light rays, each of which has a predetermined wavelength. The wavelength of the plurality of light rays varies in a predetermined manner across a width of the collimated light beam. A wavelength-discriminating detector determines an intensity of light reflected from the workpiece surface and detects wavelength-specific characteristics of the received reflected light. Significantly, the wavelength-specific characteristics of the reflected light are related to the distance of the workpiece surface from the detector. Specifically, the multi-wavelength projector includes a collimated light source that generates a collimated light beam.

Abstract: A low-cost-of-manufacture, portable, capable-of-adjustment range finder for estimating distances between the user and one or more objects with a known width, height or other linear dimension (such as a cup on a putting green, a target for target shooting, a military vehicle, etc.) is disclosed. In each of its embodiments, the invention relates to, and relies on, the fact that the image of an object appears to decrease in size as distance increases. In the preferred embodiment, an opening is formed through which to view the object, and recorded information is expressed on, in or included with the device so that the user can correlate the position of the object image to predetermined distance information. The shape and size of the opening are reasonably variable, but, once the size and shape are determined, the position of the distance information is fixed at the position on the opening where the image size corresponds to the indicated distance.

Abstract: Apparatus and a method for the detection and identification of light diverting and transparent defects with optical properties in a transparent medium. The apparatus has a light source with an aperture stop, a lens system focusing an image of the aperture stop at a plane, and means to pass the transparent medium through said column of light. The apparatus and method provide dark view images of the defects. The apparatus and method may be combined with a viewing area inspection system. The transparent medium may be curved, and especially face plates for cathode ray tubes.

Abstract: As a scanning device for positioning the irradiation position of the laser beam emitted from a laser oscillator at a position of arbitrary coordinates in the commanded mutually orthogonal X-axis direction and Y-axis direction, two galvanomirrors having mutually orthogonal rotary axes and a scan lens are provided, and the light generated from a printed circuit board irradiated with laser beam is detected by a detector, and approval or rejection of inspection result at each position of coordinates is judged on the basis of the output signal of the detector.

Abstract: A method for determining the concentration of heparin in a fluid sample comprising: (a) providing a fluid sample containing heparin; (b) adding to the fluid sample a solution of a dye to form a mixture of sample and dye, wherein the dye interacts with the heparin in the sample so that the absorption spectrum of the mixture of sample and dye in the visible range varies as a result of the interaction in a manner quantitatively dependent on the heparin concentration; (c) determining the absorption spectrum in the visible range of the mixture of sample and dye; and (d) calculating a spectral parameter representative of both the reduction in the absorption of the free dye in solution and the increase in the absorption of the dye-heparin complex, the value of the spectral parameter being indicative of the concentration of heparin present in the fluid sample, in order to determine the concentration of heparin present in the fluid sample.