Abstract: A volumetric feed control apparatus for a build material element such as a filament used in a three-dimensional modeling machine having an application tip includes a pair of feed rollers feeding the filament to the application tip, and a sensor or sensor system feeding information to a central processing unit that continuously computes the effective cross section of the filament using the signals received from the sensor or sensor system. The central processing unit controls the speed of a DC servo or stepper motor which in turn rotates the feed rollers to advance the filament toward the application tip of the modeling machine. The central processing unit adjusts the speed of the feed rollers to supply a constant flow rate of material to the application tip. Alternatively, the sensor system can be incorporated into the feed rollers, eliminating the need for further space constraints.

Abstract: A method of making a three dimensional object by depositing material in a predetermined pattern on a receiving surface, and introducing a predetermined porosity into the object being formed by positioning the deposited material so as to introduce pockets of air or other fluid into the part, and by adjusting the rate at which the material is dispensed from the dispenser. Optimal porosities in the object to be built depend upon the shape of the material when it is dispensed, but range generally from 1% to 26%.

Abstract: A method suitable for optimizing parameters characteristic of a preselected portion of an object developed in a rapid prototyping system. The method comprises the steps of identifying an object characteristic space comprising at least one dimension, the or each dimension defining a continuum for one object parameter; and, selecting a predetermined subset of said object characteristic space comprising desired optimal characteristics of the preselected portion of the object.

Abstract: Ionization of air without the use of corona discharge tips, thereby to avoid the generation of particulates from corrosion of the corona tips, is accomplished by use of a laser beam focussed to a small focal volume of intense electric field adjacent a semiconductor chip. The electric field is sufficiently intense to ionize air. In the manufacture of a semiconductor circuit chip, during those steps which are conducted in an air environment, opportunity exists to remove from a surface of a chip, or wafer, charge acquired during the manufacturing process. The ionized air is passed along the chip surface. Ions in the air discharge local regions of the chip surface which have become charged by steps of a manufacturing process. By way of further embodiment of the invention, the ionization may be produced by injection of molecules of water into the air, which molecules are subsequently ionized by a laser beam and directed toward the chip via a light shield with the aid of a magnetic field.

Abstract: A method for determining an optimal trajectory and velocity for an open loop stepper motor driven robot (1) is disclosed, as is an open loop robotic system suitable for use in, by example, a rapid prototyping system (10). The method utilizes a deflection angle calculation of a maximal velocity for each vertex of a set of vertices that define a desired trajectory, a heap sort for globally ensuring that none of the vertices have an excessive velocity, and a vertex adding technique that ensures that the robot is performing straight line moves as rapidly as is possible.

Abstract: Disclosed are methods and apparatus for fabricating a three-dimensional object in accordance with a computer-generated definition of the object that is stored within a memory. A method includes the steps of (a) evaluating the stored definition of the object to locate any un-supported features of the object; in response to locating an un-supported feature, (b) defining a support structure for the un-supported feature; (c) generating a fabrication tool movement list expressive of movements required by a fabrication tool to fabricate the object and any defined support structures; and (d) translating the fabrication tool in accordance with the generated fabrication tool movement list to fabricate the object and any defined support structures.

Abstract: A heterodyne interferometer is combined with darkfield surface particle detection for improved surface particle detection sensitivity. The probe beam and the reference beam have different wavelengths. The reference beam may either be a real reference beam or a virtual reference beam. The probe beam may be incident at the surface at either a grazing angle or at an angle substantially normal to the surface. The real reference beam is incident at the surface at a grazing angle. The detection may either be conventional heterodyne detection or a combination of heterodyne and Lloyd's mirror detection.

Abstract: Ionization of air without the use of corona discharge tips, thereby to avoid the generation of particulates from corrosion of the corona tips, is accomplished by use of a laser beam focussed to a small focal volume of intense electric field adjacent a semiconductor chip. The electric field is sufficiently intense to ionize air. In the manufacture of a semiconductor circuit chip, during those steps which are conducted in an air environment, opportunity exists to remove from a surface of a chip, or wafer, charge acquired during the manufacturing process. The ionized air is passed along the chip surface. Ions in the air discharge local regions of the chip surface which have become charged by steps of a manufacturing process. By way of further embodiment of the invention, the ionization may be produced by injection of molecules of water into the air, which molecules are subsequently ionized by a laser beam and directed toward the chip via a light shield with the aid of a magnetic field.

Abstract: A rotary viscosity pump is provided that has a housing and an impeller. The housing has a conical chamber with an outlet at a narrow end of the chamber. The impeller has a conical section with a logarithmic spiral groove along its exterior. The spacing between the housing and the impeller can have either a constant gap or a gap that decreases along the length of the impeller. The depth of the groove can be constant, increase, or decrease in depth along the length of the impeller.

Abstract: Apparatus and method for fabricating a three-dimensional object in accordance with a CAD-generated specification of the object. A closed-loop extrusion system (10) includes a nozzle (12) for extruding a material, such as a hot melt adhesive; apparatus (14, 18, 46) for controllably positioning the nozzle in accordance with the specification; and a sensor (60) for generating a feedback signal that is indicative of at least one characteristic of a most recently extruded portion of the material. Visual and non-visual feedback sensors may be employed, including optical sensors, infrared emission sensors, and proximity detection sensors. The specification of the object is converted to a bit-mapped representation thereof to improve accuracy relative to vector-based representations. Methods for determining a need for supporting structures and anti-aliasing features and for integrating the structures and features into the object specification are also disclosed.

Abstract: A particle detector that determines the presence of particles in an enclosed volume includes a laser that directs an optical beam to a beam splitter that produces first and second beams. An optical system directs the first beam into the enclosed volume. A detector is positioned adjacent the volume in order to receive back scattered optical energy arising from a particle in the volume encountering the first beam. The back scattered optical energy and the second beam are optically combined so as to overlap in a region and in the overlap region the back scattered optical energy and second beam are in the same state of focus, of the same polarization and are substantially parallel. A detector located at the overlap region produces an electrical signal indicative of the intensity of the back scattered light. A signal processor analyzes the electrical signal to determine the presence of the particle.

Abstract: Apparatus and a method for performing high resolution optical imaging in the near infrared of internal features of semiconductor wafers uses an optical device made from a material having a high index of refraction and held in very close proximity to the wafer. The optical device may either be a prism or a plano-convex lens. The plano-convex lens may be held in contact with the wafer or separated from the wafer via an air bearing or an optical coupling fluid to allow the sample to be navigated beneath the lens. The lens may be used in a number of optical instruments such as a bright field microscope, a Schlieren microscope, a dark field microscope, a Linnik interferometer, a Raman spectroscope and an absorption spectroscope.

Abstract: Apparatus and a method for performing high resolution optical imaging in the near infrared of internal features of semiconductor wafers uses an optical device made from a material having a high index of refraction and held in very close proximity to the wafer. The optical device may either be a prism or a plano-convex lens. The plano-convex lens may be held in contact with the wafer or separated from the wafer via an air bearing or an optical coupling fluid to allow the sample to be navigated beneath the lens. The lens may be used in a number of optical instruments such as a bright field microscope, a Schlieren microscope, a dark field microscope, a Linnik interferometer, a Raman spectroscope and an absorption spectroscope.

Abstract: A particle detector that determines the presence of particles in an enclosed volume includes a laser that directs a coherent optical beam to a beam splitter that produces first and second divergent beams. An optical system images the point of origin of the two divergent beams within the beam splitter into the enclosed volume, whereby the first and second beams are caused to intersect and interfere at an inspection region within the volume. A detector is positioned adjacent the volume and is responsive to light scattered from one of the beams, as a result of a particle passing through the inspection region, to produce an electrical signal indicative of the intensity of the scattered light. A signal processor analyzes the electrical signals and to determine the presence of the particle.

Abstract: An optical inspection system for patterned semiconductor wafers generates a dark field image of the wafer by applying a collimated beam of monochrome light at an incident angle with respect to the surface of the wafer of between 8.degree. and a maximum angle defined by the numerical aperture of the imaging system and collecting the light which is scattered at angles approximately normal to the surface of the wafer and within the numerical aperture of the imaging system. In addition, the incident light is at an angle of 45.degree. in the surface plane of the wafer with respect to the rectangular lines which predominate in the pattern. Before forming the dark field image, the collected light is passed through a Fourier transform filter which substantially attenuates spatial frequency components corresponding to the pattern. In the resultant dark field image, defects in the pattern and contaminating particles are accentuated relative to the pattern features.

Abstract: A thermophoretic filter cell for the filtering of particles from a liquid is constructed in a particular manner so that the liquid introduced into the filter acts as the heat sink. The cell is designed so that the thermophoretic velocity of the particles in the liquid equals or exceeds the velocity (flow rate per unit area) at which the liquid is passing through the filter.

Abstract: A bright-field, particle position determining optical system is disclosed that uses both phase shift and extinction signals to determine particle trajectories. In a first embodiment, a pair of orthogonally polarized beams are positioned along an axis that intersects a particle's flow path at an acute angle. An optical system recombines the beams after they exit the flow path, the combined beams manifesting an elliptical polarization if a particle intersects one of the beams. Bright field detectors detect polarization components of the combined beam, provide a phase shift signal between the beam's orthogonal components and provide corresponding signals to a processor. The processor determines a signal asymmetry from the phase shift signal that is indicative of a particle's position in the flow path. Another embodiment of the invention examines a signal resulting from the beam's phase shift and determines a correction factor that is dependent upon the distance of the particle from the focal plane of the beams.

Abstract: A clean non-hydrogen-containing dry gas flows through the corona points of a clean room corona air ionizer in order to suppress the generation of particles.

Abstract: A method and apparatus for monitoring process fluids used in the manufacture of semiconductor components and other microelectronic devices relies upon detection of the phase shift of a pair of optical energy beams encountering a bubble or particle in the fluid. The system distinguishes between bubbles and particles having indices of refraction greater than the surrounding fluid and between different types and sizes of particles.

Abstract: An apparatus is described for classifying particles and includes an optical system for transmitting to a focal plane which includes at least one particle, two substantially parallel optical beams, the beams being initially mutually coherent but of different polarizations. The beams are displaced and focused in the focal plane. A further optical system is positioned in the path which the beam takes after depating from the focal plane and combines the beams so that a particle-induced phase shift in one beam is manifest by a change in elliptical polarization of the combined beams. A first detector is responsive to the beam's intensity along a first polarization axis to produce a first output and a second detector is responsive to the beams intensity along a second polarization axis to produce a second output. The first and second outputs are added to provide an extinction signal and, in a separate device, are subtracted to provide to phase shift signal.