A process and apparatus for free form fabrication of a three-dimensional work piece comprising (a) feeding raw material in a solid state to a first predetermined location; (b) depositing the raw material onto a substrate as a molten pool deposit under a first processing condition; (c) monitoring the molten pool deposit for a preselected condition; (d) comparing information about the preselected condition of the monitored molten pool deposit with a predetermined desired value for the preselected condition of the monitored molten pool deposit; (e) solidifying the molten pool deposit; (f) automatically altering the first processing condition to a different processing condition based upon information obtained from the comparing step (d); and repeating steps (a) through (f) at one or more second locations for building up layer by layer a three-dimensional work piece. The apparatus is characterized by a detector that monitors a preselected condition of the deposited material and a closed loop electronic control device for controlling operation of one or more components of the apparatus in response to a detected condition by the detector.

Electron beam layer manufacturing

A method for layer-by-layer manufacturing of a three-dimensional work piece, including: (a) delivering a metallic feed material into a feed region; (b) emitting an electron beam; (c) translating the electron beam through a first predetermined raster pattern frame that includes: (i) a plurality of points within the feed region; and (ii) a plurality of points in a substrate region that is outside of the feed region; (d) monitoring a condition of the feed region or the substrate region for the occurrence of any deviation from a predetermined condition; (e) upon detecting of any deviation, translating the electron beam through at least one second predetermined raster pattern frame that maintains the melting beam power density level substantially the same, but alters the substrate beam power density level; and (f) repeating steps (a) through (e) at one or more second locations for building up layer-by-layer.

Raster methodology, apparatus and system for electron beam layer manufacturing using closed loop control

Bradbury-Nielson gates for the modulation of beams of charged particles, particularly ion beams in mass spectrometry, have been produced with an adjustable wire spacing down to 0.075 mm or a smaller spacing. The gates are robust, they can be fabricated in less than 3 hours, and the method of production is reproducible. In time-of-flight mass spectrometers, fine wire spacing leads to improvements in mass resolution and modulation rates. Gates that were produced using this new method have been installed in a Hadamard transform time-of-flight mass spectrometer in order to demonstrate their utility.

Gate for modulating beam of charged particles and method for making same

The present invention provides a system and method that facilitates measuring and imaging topographical features of a substrate, including lines and trenches having reentrant profiles. One aspect of the invention provides an electron microscope that simultaneously scans a substrate with two or more electron beams that are directed against the substrate with substantially differing angles of incidence. Secondary electrons resulting from the interaction of the substrate with the beams are detected by one or more secondary electron detectors. Each secondary electron detector may simultaneously receive secondary electrons resulting from the interaction of the substrate with two or more electron beams. In another of its aspects, the invention provides methods of analysis that permit the interpretation of such data to analyze critical dimensions and form images of the substrate. Critical dimensions that may be determined include feature heights and reentrant profile shapes. The topographical information provided is more complete than that of conventional SEM imaging and is obtained more rapidly than would be possible using multiple scans of a single electron beam.

Multi-beam SEM for sidewall imaging

Disclosed is a parallel wire grid and an apparatus and method for making the same The grid consists of a generally coplanar array of parallel spaced-apart wires secured between metallic frame members by an electrically conductive epoxy The method consists of continuously winding a wire about a novel winding apparatus comprising a plurality of spaced-apart generally parallel spindles Each spindle is threaded with a number of predeterminedly spaced-apart grooves which receive and accurately position the wire at predetermined positions along the spindle Overlying frame members coated with electrically conductive epoxy are then placed on either side of the wire array and are drawn together After the epoxy hardens, portions of the wire array lying outside the frame members are trimmed away

Parallel-wire grid assembly with method and apparatus for construction thereof

A beam splitter for electron beam machines with a beam splitter grid which is to be set crossways to the beam and which has a row of cross-pieces running next to one another with uniform spaces for shading the portions of beam striking it, where the cross-piece materials is replaceable in operation by cross-piece material not already acted on by the beam.

Wolfgang Stamm

Papers

Beam splitter for electron beam machines