Abstract: An electrochemical reaction assembly and methods of inducing electrochemical reactions, such as for deposition of materials on semiconductor substrates. The assembly and method achieve a highly uniform thickness and composition of deposition material or uniform etching or polishing on the semiconductor substrates by retaining the semiconductor substrates on a cathode immersed in an appropriate reaction solution wherein a wire mesh anode rotates about the continuous moving cathode during electrochemical reaction.

Abstract: An electrochemical machining method and apparatus involves the passage of a wire through a programmably controllable electrochemical machine, wherein the wire is tapered along its length to obtain a desired profile. The rate of material removal may be determined, for example, by modulating the power supplied to the electrochemical machine, or by varying the wire speed therethrough. The machine can include an electrical contact cell and a nutation cell. Electrical power is coupled to the wire via the contact cell. Relative orbital motion of the wire and the nutating cell ensures that material removal from the wire is uniform in all directions.

Abstract: A method of removing a metallic erosion shield secured by a layer of non-metallic adhesive to a leading edge structure of a helicopter rotor blade comprising, the step of providing an electric field between the metallic component and an electrode, in the presence of an electrolyte between the metallic component and the electrode whereby the erosion shield is removed by an electrochemical process.

Abstract: A method of three-dimensionally microcutting a metal material suitable for molds is provided. An electrolyte is interposed between a work piece which is made of a conductive material, and an electrode. Through application of an electrolysis voltage between the work piece and the electrode with the electrolyte interposed between them, a passive state film is formed on the surface of a to-be-cut part of the work piece. Then, the passive state film on the surface of the to-be-cut part of the work piece is cut.

Abstract: The present invention provides for a wet etch and method for preparing a semiconductor device structure from a silicon carbide wafer. A first embodiment of the wet etch comprises a vessel, a tetrahydrofurfuryl alcohol and potassium nitrite etching solution within the vessel, an electrode, a wafer support for positioning at least a portion of the silicon carbide wafer within the etching solution, and a voltage source coupled with the electrode and the wafer support. A second embodiment of the wet etch comprises a wafer carrier for holding at least one wafer, a polishing plate adjacent the wafer carrier, a voltage source having a first terminal electrically coupled with the wafer and a second terminal electrically coupled with the polishing plate, and an applicator adjacent the polishing plate for depositing an etching solution on a surface of the polishing plate.

Abstract: An electrochemical reaction assembly and methods of inducing electrochemical reactions, such as for deposition of materials on semiconductor substrates. The assembly and method achieve a highly uniform thickness and composition of deposition material or uniform etching or polishing on the semiconductor substrates by retaining the semiconductor substrates on a moving cathode immersed in an appropriate reaction solution wherein a wire mesh anode rotates about the moving cathode during electrochemical reaction.

Abstract: A method for performing fine working of a material by electrochemical reaction comprises a two-step scanning operation in which a surface topography of the material is obtained during a first scan which is used to control the position of a probe during a second scan in which an electrochemical reaction is performed. During the first scan, an electrochemical cell is constructed with a four-electrode system, including the probe, a material to be worked, a reference electrode and a counter electrode. The potential of each of the probe and the material to be worked is set so that no electrochemical reaction occurs during the first scan. Data representative of the surface topography is stored and used to control the position of the probe during the second scan in which an electrochemical cell is constructed with a three-electrode system, including the probe, the material, and the reference electrode.

Abstract: Disclosed is an electrochemical etching apparatus including a fixture for holding a workpiece; a nozzle, positioned opposite the fixture and facing the workpiece, for impinging an etchant onto the workpiece; and an electrode for applying a voltage between the electrode and the workpiece; wherein, in operation, one of the fixture and nozzle are rotated and the nozzle is moved radially outwardly so that the workpiece is spirally etched. Also disclosed is a method of spirally etching a workpiece.

Abstract: The present invention teaches a method of producing a textured surface upon an arbitrarily configured titanium or titanium alloy object for the purpose of improving bonding between the object and other materials such as polymer matrix composites and/or human bone for the direct in-growth of orthopaedic implants. The titanium or titanium alloy object is placed in an electrolytic cell having an ultrasonically agitated solution of sodium chloride therein whereby a pattern of uniform "pock mark" like pores or cavities are produced upon the object's surface. The process is very cost effective compared to other methods of producing rough surfaces on titanium and titanium, alloy components. The surface textures produced by the present invention are etched directly into the parent metal at discrete sites separated by areas unaffected by the etching process. Bonding materials to such surface textures on titanium or titanium alloy can thus support a shear load even if adhesion of the bonding material is poor.

Abstract: A method of machining the surface of an electrically conductive workpiece by application of a voltage to an electrically conductive tool spaced apart from the workpiece and moving the tool to shape or pattern the workpiece wherein variable flow of fluid is provided in the space between the tool and the workpiece. The fluid contains suspended insoluble interactive particles that are electrically conductive or are ionically conductive, but electronically insulating. The suspended particles came intermittent electrical short circuiting between the tool and the workpiece to prevent catastrophic and uncontrolled sparking or arcing during machining.

Abstract: A method and apparatus for forming a passage with a variable diameter along its length in a conductive workpiece are disclosed. The workpiece is mounted in a fixture and an externally insulated hollow electrode is positioned proximate to a surface location of the workpiece into which the passage is to be formed. A first selected voltage is connected between the electrode and the workplace with the voltage being connected to cause the electrode to act as a cathode and the workpiece to act as an anode. A pump causes an acidic electrolyte to flow through the electrode at a chosen pressure and onto the workpiece surface. The electrode is moved toward the workpiece at a first selected feed rate by a CNC controller to cause a portion of the passage to be formed at a first predetermined diameter.

Abstract: Embodiments of the present invention provide a new method for producing a three dimensional object, particularly suited to microfabrication applications. The method includes the steps of providing a substrate with a conducting interface, an electrode having a feature or features that are small relative to the substrate, and a solution. The solution has a reactant that will either etch the substrate or deposit a selected material in an electrochemical reaction. The electrode feature is placed close to but spaced from the interface. A current is passed between the electrode and the interface, through the solution, inducing a localized electrochemical reaction at the interface, resulting in either the deposition of material or the etching of the substrate. Relatively moving the electrode and the substrate along a selected trajectory, including motion normal to the interface, enables the fabrication of a three dimensional object.

Abstract: An electrode for use in a rotary electrical discharge machining (EDM) device for producing at least one curved hole in an article includes at least one curved tooth. The curved tooth lies in a plane. A perpendicular line to that plane is parallel to the axis of rotation on the rotary EDM device. At least one curved cooling hole is machined in the article.

Abstract: An electroetching tool using scanned localized application of flowing electrolyte against a workpiece such as a large area mask having high density features for the fabrication of microelectronic components. A masked molybdenum plate is suspended in a vertical direction within a tank which functions as a reservoir for a recirculating electrobyte. The electrolyte in the reservoir is filtered and pumped to a pair of travelling cathode assemblies from which the flowing electrolyte is simultaneously applied through respective charged orifices to both sides of the workpiece. The workpiece is masked on its opposite sides with mirror imaged mask apertures having corresponding opposite-sided features in registration with each other.Each orifice through which the electrolyte is applied comprises an open groove in the surface of a block of polyvinal chloride material which groove extends in a vertical direction relative to the tank. The bottom of the groove is adjacent to a conductive plate.

Abstract: A high speed electrochemical metal removal technique provides for planarization of multilayer copper interconnection in thin film modules. The process uses a neutral salt solution, is compatible with the plating process and has minimum safety and waste disposal problems. The process offers tremendous cost advantages over previously employed micromilling techniques for planarization.

Abstract: A nozzle is provided for use in electroetching a vertically oriented workpiece, comprising a housing having a top, sides, and bottom for creating a flow of etching solution on the workpiece, and means for shaping the flow of etching solution into a moving channel to improve etch uniformity of the workpiece.