Abstract: A surface inspection apparatus having multiple inspection stations to inspect a wafer for a number of characteristics. The wafer is placed on a chuck connected to a rack-and-pinion or equivalent system so that the wafer simultaneously rotates and translates under the fixed position of the inspection stations. A single light source may be used by all stations in turn. One station may be a particle detector with collection optics receiving a small select portion of the light scattered from the wafer surface. A second station may be a roughness detector with a collection system to direct a large portion of scattered light to a detector. A position sensitive detector may be used to determine the slope of the wafer surface at an inspection point when the wafer is not clamped to the chuck, giving a measure of surface deformation. These or other stations are positioned about either of two inspection points at which the beam from the light source may be directed.

Abstract: A method and apparatus for predicting the number of contaminant particles in circuit area of a patterned semiconductor wafer having a number of reflective circuit areas. The method includes forming on a wafer in specified areas, a grating test pattern, such as a line grating. The grating patterns are formed at the same time and in the same manner that repetitive circuit patterns are formed on the wafer. The wafer is then scanned by a light beam. Since the diffraction pattern caused by the grating test patterns is known, it is possible to detect when the light beam is scanning one of the known grating patterns. The diffraction pattern may be inspected for fabrication derived variations. In response to detecting a known grating pattern, a detection mechanism is activated. Since the diffraction pattern is known it may be spatially separated. In this way only light scattered by particles or defects in the pattern are collected and detected.

Abstract: A method for fabricating a microtip, cantilevered from a base and having a controllably high aspect ratio, for use in microprobe microscopy to probe variations in materials at the atomic level. A two-layer semiconductor material structure is provided, one layer being n type and the other layer being p type. A thin pencil of ions of n type is implanted through the n type layer into the p type layer, through a small aperture in a mask layer that overlies the n type layer. The p type material is then etched away, leaving the n type ion profile and the n type layer as a cantilevered microtip. The n type semiconductor layer may be replaced by a layer of any material that resists etching by the selected etchant.

Abstract: Methods for determining the presence or absence of, and the thickness or other spacial extent of, a contaminant layer at each of a plurality of two or more sites on the surface of an electrically conductive material such as a semiconductor, a metal or a metal silicide. The invention uses a change in photoemission current from an illuminated spot on the surface to determine the presence and extent of a contaminant layer at the illuminated site. Compensation is provided for the effects of capacitive current and photovoltaic current. The invention provides a pattern of illumination sites on the conductor surface that can, if desired, cover all points on the surface.

Abstract: Method and apparatus for determining the amount, if any, of residue remaining at the bottom of an aperture in a layer of dielectric or insulator material. A layer of electrically conducting material is positioned adjacent to the aperture bottom, an electron collector is positioned adjacent to the mouth of the aperture, and a voltage difference (optional) is impressed between the conducting material and the electron collector. The aperture bottom is illuminated with a light beam with photon energy greater than the electron work function of the conducting material, and a portion of the photons that comprise the light beam reach the conducting material and produce photoelectrons by photoemissive action. A photoelectron current is sensed by the electron collector, and the cleanliness of the aperture bottom is determined from the value of the current.

Abstract: A layered structure for use in an X-ray membrane (pellicle) mask or a vacuum window is provided in which an intermediate amorphous layer such as silicon dioxide is grown on a silicon substrate which provides a stress relief medium and surface properties which enhance and improve subsequent process layers by breaking the epitaxial nature of these later deposited layers. Upon subsequent deposition of an inorganic overcoat, such as SiC, on the intermediate amorphous layer, the overcoat produces a nearly defect-free layer with a substantially reduced stress of suitable quality for X-ray lithography mask fabrication. Furthermore, additional alternating layers of a silicon carbide film and an intermediate inorganic layer, such as silicon nitride, can be deposited to obtain an even smoother silicon carbide surface and stronger structure.

Abstract: A method and apparatus for detecting and classifying particles on a surface in which condensation is used to enlarge particles. An apparatus of the present invention includes a heatable wick disposed over a test surface and in fluid communication with a source of volatile liquid. A zone of vapor supersaturation is thus created in which condensation on particles on the surface can occur. A light beam directed onto the surface scans the surface. Droplets are detected by means of light scattered from the droplets. In an alternate embodiment a stream of carrier gas may be provided around the wick or bubbled through a jar of volatile liquid to direct a vapor toward the test surface. In another embodiment, multiple wicks communicate with different sources of volatile liquids. In a method of the invention, mulitple scans are made with either different levels of vapor supersaturation or different vapor compositions.

Abstract: A particle detection on a periodic patterned surface is achieved in a method and apparatus using a single light beam scanning at a shallow angle over the surface. The surface contains a plurality of identical die with streets between die. The beam scans parallel to a street direction, while a light collection system collects light scattered from the surface with a constant solid angle. The position of the collection system as well as the polarization of the light beam and collected scattered light may be arranged to maximize the particle signal compared to the pattern signal. A detector produces an electrical signal corresponding to the intensity of scattered light that is colelcted. A processor constructs templates from the electrical signal corresponding to individual die and compares the templates to identify particles. A reference template is constantly updated so that comparisons are between adjacent die.

Abstract: A confocal measuring microscope including a spectrometer and autofocus system sharing common optical elements in which the intensity of light entering the spectrometer from a particular spot on a workpiece is used to determine a focus condition for the same spot. The microscope includes at least one light source, an illumination field stop, and a microscope objective that images the stop onto a workpiece supported by a movable platform. The objective also forms an image of the illuminated portion of the object. An aperture in a second stop and intersecting the image plane passes light from part of the image to the spectrometer, while viewing optics are used to view the image. In one embodiment, a detector is placed at the zero order position, while in another embodiment a laser is placed at the zero order position. In the later embodiment an integrator circuit connected to the detector array replaces the zero order detector for measuring the total intensity of light entering the spectrometer.

Abstract: A particle detection method for matching particles detected in two scans of a surface taken at different times in which particles having a light scattering intensity above a collection threshold are first detected and the measured position and scattering intensity therefor stored in a computer memory. Corresponding first and second measured positions from the respective first and second scans are determined by forming a triangle from selected first detected particles and finding those second detected particles which form a variant triangle with matching perimeter and area. From these matching first and second particles a transformation is found for mapping first measured positions to corresponding second positions and vice versa. Areas around corresponding positions of particles having a scattering intensity above a display threshold are examined for matching particles. If not found, the area is reexamined at a reduced threshold.

Abstract: An aligner for aligning a mask and a wafer during photolithography of a semiconductor chip uses detection of the differential capacitance between two sets of conductive fingers on the mask and ridges on the wafer. An A.C. signal is coupled between the ridges and the fingers and the phase or amplitude of the signals is detected. An aligner utilizing multiple groups of ridges and fingers allows rotational alignment or two axis lateral alignment. An aligner having reference ledges to which the mask and the wafer are capacitively coupled allows alignment when the distance between the mask and the wafer is too great to permit meaningful capacitive coupling between the mask and the wafer to occur.

Abstract: A structure for use in an X-ray membrane (pellicle) mask is provided in which anodic bonding of layers is employed. Anodic bonding as used here provides a permanent bond between the layers, has zero thickness and provides substantial improvements in the obtained flatness of the mask by eliminating conventional glue for attachment. By applying a voltage between a layer, such as silicon, and a glass plate, and simultaneously heating both elements a permanent bond is established which is extremely flat thus providing minimum misalignment of the mask during subsequent X-ray lithography fabrication.

Abstract: An X-ray lithography apparatus permits the successive exposure of each of four quadrants of a semiconductor wafer through a single mask. The mask overlays one quadrant of the wafer at a time and the wafer is rotated through 90 degrees after exposure of a quadrant to allow exposure of succeeding wafer quadrants; each wafer quadrant is independently aligned to the mask prior to exposure. In an alternative preferred embodiment, a rotatable diaphragm is used to select a single mask quadrant from a mask which overlays the entire surface of the semiconductor wafer. Both the wafer and the diaphragm may be rotated to allow various exposure combinations of mask and wafer quadrants.

Abstract: A layered structure for use in an X-ray membrane (pellicle) mask or a vacuum window is provided in which an intermediate amorphous layer such as silicon dioxide is grown on a silicon substrate which provides a stress relief medium and surface properties which enhance and improve subsequent process layers by breaking the epitaxial nature of these later deposited layers. Upon subsequent deposition of an inorganic overcoat, such as SiC, on the intermediate amorphous layer, the overcoat produces a nearly defect-free layer with a substantially reduced stress of suitable quality for X-ray lithography mask fabrication. Furthermore, additional alternating layers of a silicon carbide film and an intermediate inorganic layer, such as silicon nitride, can be deposited to obtain an even smoother silicon carbide surface and stronger structure.

Abstract: An aligner for aligning a mask and a wafer during photolithography of a semiconductor chip uses detection of the differential capacitance between two sets of conductive fingers on the mask and ridges on the wafer. An A.C. signal is applied to the ridges and the phase or amplitude of the signals coupled to the two sets of fingers is detected and compared. A shield is positioned between the ridges and the fingers to ensure that coupling occurs only between desired portions of the ridges and the fingers.

Abstract: A method of making an electron permeable window is provided which entails depositing a thin film of an inert, high strength material or compound having a low atomic number onto a substrate by chemical vapor deposition (CVD). Following that deposition, a window pattern and window support perimeter are photolithographically defined and the substrate is etched to leave the desired window structure. For a particular class of materials including SiC, BN, B.sub.4 C, Si.sub.3 N.sub.4, and Al.sub.4 C.sub.3, films are provided which are exceedingly tough and pinhole free, and which exhibit nearly zero internal stress. Furthermore, due to their extreme strength, these materials allow fabrication of extremely thin windows. In addition, because of their low atomic number and density, they have excellent electron penetration characteristics at low beam voltages (15 to 30kV), so that most conventional CRT deflection schemes can be used to direct the beam.

Abstract: A method of making an electron permeable window is provided which entails depositing a thin film of an inert, high strength material or compound having a low atomic number onto a substrate by chemical vapor deposition (CVD). Following that deposition, a window pattern and window support perimeter are photolithographically defined and the substrate is etched to leave the desired window structure. For a particular class of materials including SiC, BN, B.sub.4 C, Si.sub.3 N.sub.4, and Al.sub.4 C.sub.3, films are provided which are exceedingly tough and pinhole free, and which exhibit nearly zero internal stress. Furthermore, due to their extreme strength, these materials allow fabrication of extremely thin windows. In addition, because of their low atomic number and density, they have excellent electron penetration characteristics at low beam voltages (15 to 30 kV), so that most conventional CRT deflection schemes can be used to direct the beam.

Abstract: A new type of thermal ink jet print head is provided which is driven by an electron beam. The print head is constructed of an electron permeable thin film (electron window) which in one embodiment, has on one of its surfaces a plurality of electron absorbing (heater) pads that are in thermal contact with an ink reservoir. As electrons from a CRT traverse the thin film and are absorbed by a pad, they introduce an extremely large and rapid temperature increase in the pad. As a result, a sufficient amount of thermal energy is absorbed by the ink to cause a vapor explosion within the ink, thereby ejecting ink droplets from a nearby orifice in the ink reservoir. In another embodiment, the electrons traverse the window and are absorbed in the ink rather than in pads, and in another embodiment the electrons are absorbed directly in the window itself.

Abstract: An X-Y recorder for high speed plotting on a plain web, i.e., a web without registration holes or other special means to maintain alignment of the web during plotting. Two embodiments of these plotters are disclosed with one degree of motion being achieved by moving the web and the second degree of motion being obtained by moving a pen assembly substantially perpendicularly to the movement of the web. To enhance the repeatability of the plotting on the web as it is moved back and forth, a random rough surfaced drive wheel assembly is included with that wheel surface making indentations along one surface of the driven edge of the web as it is first passed through the drive wheel assembly. Then as the web is reversed, these indentations substantially remesh with the random rough surface of the drive wheels.

Abstract: An electron capture detector in which a thermionic source such as a filament provides electrons for the reaction in a source chamber having a port that connects to a detection chamber having a collector. Guard gas is introduced into the source chamber and sample gas into the detection chamber, and an exhaust port is provided in the detection chamber.