Abstract: A ceramic substrate made of a dielectric material including silicon carbide particles, which is used as a forming material, in which the number of the silicon carbide particles per unit area on the surface of the substrate is smaller than the number of the silicon carbide particles per unit area in a cross section of the substrate.

Abstract: In a repairing method for an electrostatic chuck device in which at least an adhesive layer and an attracting layer are provided on a metal base, a side surface of an eroded adhesive layer is wound with a string-like adhesive and thermal compression is performed thereafter. A repairing apparatus for an electrostatic chuck device, which is used in the repairing method, includes a rotatable table for rotating the electrostatic chuck device and a bobbin for supplying the adhesive to the adhesive layer.

Abstract: In this method, magnetic studs housed in a plate are connected to magnetic flux measuring circuits, which define measuring zones, and to power circuits that make it possible to magnetize or demagnetize the studs. The method comprises prior steps that consist in determining (100) at least two treatment zones each defined by at least one measuring zone and defining (102) a surface of the clamping plate in contact with the part to be clamped, as well as following steps consisting, for each treatment zone, in identifying (103) one or more magnetic studs included in a surface of the clamping plate in contact with the part to be clamped, measuring (105) the magnetic flux produced by the stud or studs identified previously, calculating (106) an actual magnetic clamping force based on the measurement of the preceding step and on the identification made previously, calculating (108) a theoretical magnetic force thanks to this identification.

Abstract: According to one aspect, the invention provides a table for compensating deformation in flexible foils (1) The table comprises a supportive base (2) and a deformation compensation system (3). This system comprises a plurality of movable elements (4), supported by the base (2), wherein the movable elements form a surface for supporting the flexible foil. The movable elements comprise clamps (6) for clamping the foil (5). The movable elements (4) are individually movable parallel to the surface for supporting the foil, so as to stretch the clamped foil into a predefined shape. The table for compensating deformation in flexible foils may be used in a manufacturing process of flexible functional foils to compensate deformation of the foils during sequential patterning.

Abstract: A stack of ferromagnetic sheets is gripped, lifted, and transported by first engaging with an uppermost sheet of the stack a plurality of magnet assemblies of a magnetic grab, each assembly having at least one electromagnet, then electrically energizing the electromagnets and lifting the stack with the grab while monitoring a magnetic flux of each electromagnet. A controller then compares the fluxes of the electromagnets, and varies the electrical energization of at least one of the electromagnets such that the fluxes of all the electromagnets are generally equal. The system has at least one flux sensor on each of the magnet assemblies and connected to the controller.

Abstract: The magnetic fixing device comprises a clamping plate having a fixing surface to which a clamping object is fixed and plural magnetic force generation mechanisms. The magnetic force generation mechanisms each comprise a magnetic material member facing the fixing surface, plural permanent magnets arranged around the outer periphery of the magnetic material member, a first Alnico magnet placed on the back of the magnetic material member, and a first coil for switching the polarity of the first Alnico magnet, and can be switched between the absorption state in which the clamping object is adsorbed and the non-absorption state in which the clamping object is not adsorbed. An operation state indication mechanism capable of presenting an indicator indicating that the plural magnetic force generation mechanisms are in the absorption state or in the non-absorption state is provided on the fixing surface or outer periphery of the clamping plate.

Abstract: An exciting voltage arithmetic portion calculates an exciting voltage of an electromagnet using a signal of a gap sensor. On the other hand, a sensorless exciting voltage arithmetic portion calculates an exciting voltage of the electromagnet using a signal of the current sensor. The exciting voltage adjusting portion adjusts a mixing ratio between an output value of an exciting voltage arithmetic portion and an output value of the sensorless exciting voltage arithmetic portion corresponding to a gap length. The excitation of the electromagnet is controlled according to an output value of the exciting voltage adjusting portion so as to reduce influences of noises on the gap sensors thereby always achieving a stable levitation control.

Abstract: A method and apparatus for moving magnetic material includes an electromagnet for lifting the magnetic material where upon its release, the residual magnetic flux of the lifted magnetic material is reduced. The apparatus includes a generator coupled to the electromagnet. The generator includes a control input and an armature having a voltage output. A controller has an output coupled to the generator's control input and armature voltage output, whereupon receiving a release material signal from an operator interface panel to release the magnetic material from the electromagnet, the controller transmits a plurality of control signals, one of which is at least partially dependent upon the duration of a previously transmitted control signal, to effectively alternate the polarity and reduce the magnitude of the magnetizing force of the electromagnet.

Abstract: An electrostatic chuck includes a base plate, an electrode layer having flexibility, covering the surface of the base plate, and a power supply unit for electrically connecting the electrode layer to the power source side. The power supply unit includes a connection piece including a wire, and electrically conductive components to be used in connection to the power source side. The wire is connected to an electrode of the electrode layer, and extends from the side edge of the electrode layer. The electrically conductive component is electrically connected with the wire, and fixes the connection piece bent along the side surface of the base plate to the base plate.

Abstract: A control circuit that drives an electronic actuator. The control circuit includes a direct voltage source, a chopper circuit arranged between the source and an electric actuator, and an electronic control circuit designed to apply to the chopper circuit a command signal of the PWM type, with a predefined ON/OFF switching period and a predetermined duty cycle, for a predefined activation time, to produce a flow, within the electric actuator, of a correspondingly switched current having a nominal duration corresponding to the activation time. The control circuit detects the last whole or complete switching period included within the activation time, splits, in accordance with a predefined duty cycle, the final interval including the last complete switching period and any subsequent fraction of a switching period included within the activation time, and drives the chopper circuit in this final interval.

Abstract: An electrostatic gripper for moving wafers includes bipolar electrodes with an insulating layer of zirconium oxide, which are positioned on a circuit board. The gripper is produced by a pressing process and can be operated with a DC voltage of less than 900 V. As a result, heating of the wafer is almost completely prevented even under a vacuum.

Abstract: Substrates such as silicon wafers, flat panel displays, and hard disk drive head substrates are electrostatically gripped using power derived from a physically separated source. Noncontacting coupling permits operation in vacuum as a result of its efficient energy conversion. Bidirectional communications between a controller and the remote gripper electronics along its power coupling lines is enabled. Inclusion of a communications link allows monitoring of system status and full control over the substrate sensing, grip, and release processes. The system of the present invention provides freedom from rf bias filtering considerations, and enables installation of grippers on robot arms without stretching, bending, or sliding electrical connections.

Abstract: A plasma processing apparatus comprises: a body that comprises a vacuum processing chamber with a wafer stage on which a semiconductor wafer is held, a plasma producing unit for producing plasma within the vacuum chamber, and a high frequency source for applying a high frequency bias voltage to the wafer stage. A control unit controls various parameters of the body of the plasma processing apparatus. The control unit comprises a detecting unit for detecting the high frequency voltage or high frequency current applied to the wafer stage and for calculating a difference in phase between the high frequency voltage and the high frequency current, and a unit for obtaining a characteristic of the plasma or an electric characteristic of the plasma processing apparatus based on the detected high frequency voltage, the detected high frequency current, and the obtained difference in phase.

Abstract: A module is formed in which semiconductor components are soldered to an electrically conductive heat sink. The electrically conductive heat sink is formed so that it will serve as an electrical bus in an electronic device. The chips of the semiconductor component are metallurgically bonded to the surface of the heat sink. The heat sink uses a heat transfer fluid that flows through an interior of the heat sink, the interior containing an internal element. In the preferred embodiment, the internal element is a plurality of silver plated copper balls. The copper balls are brazed to each other and to the walls of the heat sinks in an assembly process. The heat sink housing will typically be made from copper, with one surface made from molybdenum so that the expansion and contraction of the heat sink housing molybdenum surface will be similar to that of the silicon substrate of the chips, thereby avoiding the problem of the chip substrate cracking and breaking due to thermal flexing.

Abstract: A rectifier assembly employs a set of diodes to rectify alternating current from an alternator to direct current for use by the electrical system of an automobile. The rectifier includes a plurality of thermal safety disconnects coupled along circuit paths within the rectifier assembly. When the resultant temperature caused by the heat provided to the safety disconnect as a result of the diodes overheating is above a threshold level, the safety disconnect melts away to disconnect the circuit path associated with the safety disconnect.

Abstract: Embodiments of the present invention generally provide a chuck for a semiconductor processing system, wherein the chuck includes an annular substrate receiving member having an upper substrate receiving surface formed thereon, a hemispherical reinforcement member affixed to a lower surface of the substrate receiving member, and an elongated stem portion affixed at a distal end to the hemispherical reinforcement member.

Abstract: A novel control circuit for magnetizing and demagnetizing an electric permanent chuck includes a single alternating current source with a selected frequency and phase. A circuit that generates electrical pulses is coupled to the alternating current source to produce pulses at a multiple of the frequency of the alternating current source. The pulse generating circuitry also sets the phase of the pulses relative to the phase of the alternating current source at a predetermined value. The pulses are then applied to the gates of one or more silicon controlled rectifiers (“SCRs”) which control current flow through the electric permanent chuck. By adjusting the phase of the electrical pulses, the amount of current and average DC voltage applied to a coil of the electric permanent chuck through an SCR can be controlled.

Abstract: An apparatus and method for controlling a lifting magnet (12) of a materials handling machine (10) to eliminate arcing between contacts (70-80) within the magnet controller (26) as is well as is large voltage spikes. The controller (26) selectively excites the shunt field windings (66,68) of a direct current generator (22). The magnitude and direction of the current passing through the shunt field windings (66,68) is varied by the magnet controller (26) to control the magnitude and polarity of the voltage at the generator output (23). The armature (60) of the generator (22) is rotatably driven by a hydraulic motor at an essentially constant speed to minimize voltage variations at the output (23) of the generator (22). At least the drop cycle is controlled through use of a current transducer (200) that senses current flowing to the lifting magnet so that the electronic controller is able to control the flow of current to the lifting magnet based upon the sensed current in the magnet circuit.

Abstract: An improved electromagnetic chuck which does not require a continuous direct current supply while being magnetized, including a main body defining a plurality of recesses and forming a cover, which includes a plurality of magnetically conductive portions and non-magnetically conductive portions alternately arranged, a plurality of magnetic units arranged within said plurality of recesses, and a magnetizing/demagnetizing circuit for magnetizing/demagnetizing said plurality of magnetic units, is provided. The magnetizing/demagnetizing circuit includes a magnetizing circuit, a demagnetizing circuit and an output circuit, by which a direct current is generated to magnetize the electromagnetic chuck, or a pair of positive and negative phase pulses with a gradually increased frequency is generated to quickly demagnetize the electromagnetic chuck.

Abstract: A hydraulic circuit (124) is defined in a manifold (130) which may be aluminum, steel, or any other suitable material. The circuit (124) regulates the flow of hydraulic fluid to the hydraulic motor (120) and thus ensures that the motor rotates at an essentially constant speed, independent of the speed of the hydraulic pump (122) supplying the circuit. The circuit includes a pressure compensated flow control valve assembly (140) with an adjustable flow control valve (142) that regulates the flow of hydraulic fluid to the motor (120). The assembly (140) also includes a balanced piston-type pressure compensator (144) that ensures a select pressure differential across the flow control valve (142) such that the flow through the valve (142) remains at least essentially constant. This constant flow through the pressure compensated flow control valve assembly (140) ensures an essentially constant rotational speed of the motor (120).

Abstract: An apparatus and method for controlling a lifting magnet (12) of a materials handling machine (10) to eliminate arcing between contacts (70-80) within the magnet controller (26) as well as large voltage spikes. The controller (26) selectively excites the shunt field windings (66,68) of a direct current generator (22). The magnitude and direction of the current passing through the shunt field windings (66,68) is varied by the magnet controller (26) to control the magnitude and polarity of the voltage at the generator output (23). The armature (60) of the generator (22) is rotatably driven by a hydraulic motor at an essentially constant speed to minimize voltage variations at the output (23) of the generator (22). The magnet controller (26) includes a programmable logic controller (40) which selectively opens and closes the contactors (70-80) within the controller (26).

Abstract: A lift pin 95 for dechucking a substrate 15 held to a chuck 50 by residual electrostatic charge, the substrate being processed in a plasma formed using RF currents, is described. The lift pin 95 comprises (a) a movable elongated member 110 having a tip 115 suitable for lifting and lowering the substrate 15 off the chuck 50, and capable of forming an electrically conductive path between the substrate 15 and a current sink 105. The electrically conductive path comprises at least one of the following: (1) a frequency selective filter capable of filtering RF currents flowing therethrough so that substantially no RF currents flow through the filter; or (2) a resistor having a resistance sufficiently elevated to reduce the voltage caused by RF currents flowing therethrough, by at least about 50%.

Abstract: Bit lines BL0 and /BL0 are connected to a sense amplifier SA0, the gate of a first MOS transistor to a first word line WL0, a first electrode of a first ferrodielectric capacitor Cs1 to the source of the first Qn, the drain of the first Qn to BL0, a second electrode of Cs1 to a first plate electrode CP0, the gate of a second MOS transistor Qn to a second word line DWL0, a first electrode of a second ferrodielectric capacitor Cd2 to the source of the second Qn, the drain of the second Qn to /BL0, and a second electrode of Cd1 to a second plate electrode DCP0, and after turning off the second Qn, the logic voltage of DCP0 is inverted. Hence, in a semiconductor memory device employing the ferrodielectric element, the dummy memory capacitor is initialized securely, and high speed reading is enabled without concentration of power consumption.

Abstract: Apparatus for demagnetizing and magnetizing a chuck, having circuitry for connection with a 3-phase 4-line AC source, and including a power circuit and a control circuit. The power circuit leads directly from the source to the chuck, without transformers and capacitors. The three phases of the AC are individually impressed on the chuck, at corresponding angles, and rectifiers rectify the current at each phase. The circuitry will accommodate a single chuck, or selective ones of multiple chucks (e.g., nine). The voltage provided by the source is of a predetermined value (e.g., 230 V) and voltage of a greater value (e.g., 290 V) can be applied for demagnetizing. Solid state controls are provided, the individual phases of the current, for controlling greater and lesser voltages, and for putting a single chuck, or selected ones of multiple chucks, in circuit.

Abstract: An electrostatic chuck for semiconductor wafers (10) uses at least three electrodes (12, 13, 14). Two electrodes (13, 14) defining a substantially planar surface and embedded in a thin dielectric film (11), are respectively excited by a low-frequency A.C. supply (15, 16, 17, 18, 23) to produce sinewave fields of controlled amplitude and phase, provided a low resultant voltage on the wafer surface. A third electrode (12) acts as a shield electrode or as a reference point for the other two electrodes (13, 14). In addition, by controlled rates of voltage application and removal, low voltage gradients are obtained on the wafer (10); and no retentive forces exist in the dielectric medium (11). A low A.C. amplitude excitation of the chuck enables capacitive current sensing of the relative positions of the wafer (10) and the dielectric film (11), enabling simple control of voltage application to the two electrodes (13, 14).

Abstract: A chuck and a power transformer having a pair of secondaries for applying continuous unidirectional DC to the chuck. A pair of control transformers each having a pair of secondaries related to respective ones of the power secondaries, for producing opposite polarities on the chuck. A timer operable through a maximum time interval for controlling the control transformers and thereby producing DC on the chuck of a level according to that time interval, and settable to lesser time intervals for producing DC of correspondingly lesser levels. Means for producing DC in each of oppositee polarities, and each throughout a corresponding time interval according to the setting of the timer. Oscillator means controlling the control transformers for thereby controlling the power transformer for producing DC of opposite polarities in a series of steps, and interposing resistances of successively greater values in the steps to reduce the charge on the chuck to zero at the last step.

Abstract: In the magnetic chuck control disclosed herein, the chuck winding is selectively energized in one direction or the other through respective triggerable semiconductor current switching devices. Successively reducing current levels are applied in successive phases of operation, the polarity of the current being reversed in successive phases. During a first portion of each phase the device is triggered to apply a corresponding preselectable voltage. During a second portion of each phase the switching devices are triggered quite late to provide an average voltage which opposes the current flow which was induced during the first portion thereby to quickly reduce the level of current flowing in the winding.

Abstract: An electrostatic chuck for holding a work by electrostatic forces, which has an electrostatic attraction body for attracting the work, an electrostatic conductive support body for supporting the electrostatic attraction body, channels for passing cooling medium therethrough and cover means for covering the exposed surfaces of the support body except a portion thereof over which the work is placed. This chuck can not only prevent impure matters from generating from the surfaces of the support body but also prevent damages due to heat.

Abstract: An electromagnet control apparatus having a remote control switch assembly switchable between a number of positions representing full, variable, residual and zero levels of magnetization. Means are provided for causing the electromagnet to be fully energized for several seconds before being dropped to the residual level of magnetization whenever the switch assembly is switched to a residual setting.

Abstract: Apparatus for controlling the magnetizing and demagnetizing of the chuck in a machine tool, and the workpieces held thereon. A plurality of individual chucks are incorporated in the machine tool, and they are selectively brought into circuit according to the characteristics of workpieces. The demagnetizing phase is controlled as to length of overall period and the number of reversing steps in that period.

Abstract: Prior art magnetic chuck control systems do not utilize state of the art components and do not sufficiently isolate the power output from control circuits. The instant invention discloses a magnetic chuck control system employing solid state circuitry including a power output circuit (24) adapted to apply a DC voltage to an object such as a magnetic chuck (12) or the like so as to magnetize the same. The power output circuit employs a triac reversing circuit and is interfaced with a digital control circuit (26) and a digital-to-analog converter circuit (30) so as to apply alternating polarity voltage signals of successively reduced magnitude to the chuck during a demagnetizing operation. All high voltage is confined to the power output circuit so as to provide significant safety protection to the operator.

Abstract: An electromagnetic chuck power supply and control comprising a magnetic amplifier consisting of a saturable reactor supplying DC power at its output across the electromagnet coils of the electromagnetic chuck. A controllably variable DC current is supplied across the control winding of the magnetic amplifier such that the DC power at the output of the magnetic amplifier is inversely proportional to the DC current flow through the control winding. Variable workpiece holding power is thus obtained at the electromagnetic chuck. At full control current flow, the electromagnetic chuck has no holding power except that due to the residual magnetization of the workpiece. In the event of complete failure of the control current circuit, maximum holding force is applied by the chuck to the workpiece.

Abstract: Continuous demagnetizing for a dial feeder grinder. The grinder has a rotating table, and a plurality of grinding heads for successively grinding workpieces put on the table and carried therepast. The workpieces are held on the table by a magnetic chuck, and to remove them, they must be demagnetized. The chuck is made up of wedge shape segments, and those segments are magnetized and demagnetized, in a rotation of the table, in putting the workpieces on, and removing them from, the table, both these steps being performed in a single rotation of the table. The magnetism of the chuck segments is controlled by collector rings arranged in sections around the table, and the chuck is provided with brushes engaging the collector ring segments for sequentially energizing the chuck segments, and, in conjunction therewith, controlling the demagnetizing steps.

Abstract: An electronic current control device for energizing and de-energizing an electromagnet, such as a magnetic chuck, includes a DC power source preferably in the form of a phase-controlled SCR power unit. A conduction angle control signal is routed to positive or negative gates in the power unit to determine polarity and amplitude of direct current through the electromagnet windings. In the "on" mode an analog current feedback loop maintains a predetermined magnetizing level of current through the windings. In the demagnetize mode, a digital system decreases the current amplitude stepwise while alternating the polarity. When the sensed current attains the selected peak level for a given step, a digital count is decremented. The polarity is reversed according to the odd or even count, and a new peak reference level is established corresponding to the digital count.

Abstract: A magnetic holder for releasably retaining a ferromagnetic object, having a core member composed of a semi-hard magnetic material magnetized permanently by an instantaneous capacitor discharge current passing in a first direction through coils wound on the core member to permanently retain the object. The capacitor discharge current is passed in a second direction opposite to the first through the coils to demagnetize the previously magnetizer core member and allow the object to be magnetically released.

Abstract: In the electromagnet control apparatus described herein, demagnetization of the electromagnet and a workpiece held thereby, following a period of holding, is effected by stepwise adjustment of the phase setting of a power control means such as a triggerable, semi-conductor switching device, thereby controlling the average AC voltage applied to a full wave bridge through which the electromagnet is energized. Reversing switch means are interposed between the bridge and the electromagnet for reversing the direction of the energizing current at each successive step.

Abstract: A battery charge system for a transfer magnet (heretofore generally known as a lift magnet) and for a chuck control. In the case of the transfer magnet, the battery provides constant power, while in the case of the chuck control, it serves as a standby power. The charge system is automatically connected when the charge on the battery reaches a predetermined minimum, and disconnected when it is charged to a predetermined maximum. The battery in each case is connected with the usual utility source of AC, and upon the voltage of the battery reaching the levels mentioned, the AC source is respectively connected or disconnected.

Abstract: An apparatus is disclosed for controlling a magnetic clamp on a machine tool having a machine slide driven by a feed motor in response to a motor power source. Current supplied to the feed motor by the motor power source is monitored by a magnetic coil control circuit. The coil control circuit is operative to regulate the supply of current to the magnetic clamp as a function of the current supplied to the feed motor. A machine slide control circuit is disclosed for inhibiting the motion of the machine slide as a function of the current supplied to the feed motor.