Abstract: A removable lid for a pool skimmer, the lid including at least one, and preferably two, manually operated latches that prevent inadvertent removal of the lid and thereby eliminate a potentially hazardous condition posed by lids that can be removed by wind action, wave action, or by accidentally tripping on an incorrectly installed lid. Preferably, the lid has diametrically opposed latches, each having a bendable member with a camming surface that bends the latch to fit within a skimmer collar and then allows the latch to snap into a retaining position when the lid is completely installed. Access holes in the lid facilitate manual operation of the latches for removal of the lid for maintenance purposes.

Abstract: A plasma generator having two groups of interleaved electrodes to which power is allied at high or radio frequency, to form a plasma in a region sufficiently removed from a substrate to avoid damage and unwanted exposure of the substrate to the plasma. In one embodiment of the invention, the electrodes are flat parallel plates. One group of electrodes includes all the odd-numbered plates and the other group includes all the even-numbered plates. In another embodiment of the invention, the electrodes are concentric cylinders instead of flat plates. In either case, plasma generation makes use of a relatively large electrode surface area in a small volume, and the resulting plasma is not in direct contact with the substrate being processed.

Abstract: A technique for automatically compensating for differences in orientation of a workpiece, such as a rectangular substrate, a substrate cassette, a loadlock for accessing a vacuum chamber, and a substrate support on a robot mechanism. Sensors on the substrate support detect the position of a front edge of a substrate, a cassette or a loadlock, and measurements taken at the time the sensors are tripped by the edge are used to compute linear, angular and radial position corrections. More specifically, in moving a substrate from a cassette to the loadlock, the substrate support compensates for the orientation of the cassette, compensates for the orientation of the substrate within the cassette, and withdraws the substrate without contact with the cassette walls, and without the need for moving edge guides to orient the substrate.

Abstract: A method and apparatus for calibrating a robot for differences between the actual and predicted positions of a robot chamber with respect to the robot, and for differences between the actual and predicted positions of a processing chamber with respect to the robot. A substrate support on the robot is first moved angularly across a fixed sensor in the robot chamber, to detect the actual position of the sensor in terms of angle, and second is moved radially out across the fixed sensor to detect actual position in terms of radius with respect to a center of rotation. The difference, if any, between the actual and predicted positions of the sensor is used to calibrate a home position of the robot. A similar technique is used to calibrate the robot for any discrepancy between the actual and predicted positions of a processing chamber adjoining the robot chamber.

Abstract: A technique for maintaining a satellite in an assigned orbit without control or intervention from the ground. Autonomously obtained navigational data provide a measurement of the actual orbit in which the satellite is traveling. So long as the measured orbit conforms to a desired orbit to within a preselected tolerance, periodic corrections of equal magnitude are made to the satellite's velocity, based on a prediction of the effect of atmospheric drag on the orbit. Measurement of the orbit is made by observation of the time that the satellite passes a reference point in the orbit, such as by crossing the ascending node. If the measured orbit departs from the desired orbit by more than the preselected tolerance, a velocity correction of a magnitude different from the one based on prediction is applied to the satellite. For a decaying orbit, the magnitude of the velocity correction is increased above the correction value based on prediction.

Abstract: Apparatus, and a related method for its operation, for isolating a semiconductor laser diode physically and thermally from a drive circuit used to generate large modulating currents applied to the laser diode. Bias and modulating currents generated by the drive circuit are transmitted to the laser diode over a selected length of transmission line, such as a coaxial cable. Generation of heat close to the laser diode is minimized by a backmatching technique in which impedance matching is effected entirely at the drive circuit end of the transmission line. An impedance matching the characteristic impedance of the transmission line is connected across the line at the drive circuit end, allowing modulation currents to be transmitted to the laser diode without distortion.

Abstract: An electron beam exposure method for controlling the solubility of resist layers used in a variety of lithography processes, to permit removal of the resist material from selected positions and depths in the resist. By controlling the energy of a uniform electron beam impinging on the resist, the method selects a resist depth for applying a dose of electrons, the effect of which is to change the solubility properties of the resist material at the selected positions and depths. Subsequent removal of unwanted portions of the resist produces desired resist wall slope and edge profiles in the developed patterns in photoresist. One embodiment of the invention uses the same basic method to produce three-dimensional structures in the resist material, including bridge-like structures in which lower layers are removed from beneath intact upper layers.

Abstract: A device for packing or compressing refuse material into a container, which my be mounted on a vehicle or installed at a fixed site. The device includes a paddle mounted for oscillatory angular motion about a generally vertical axis in a hopper assembly. The paddle is oscillated by a crank arm mounted on the same axis and in a fixed angular relationship with the paddle. The crank arm, in turn, is driven by a pair of extensible devices, such as hydraulic cylinders, which are pivotally coupled to the crank arm and pivotally anchored by their other ends to selected points on the hopper frame. The selection of anchor points for the hydraulic cylinders assures that they act in unison over much of the range of oscillatory motion of the paddle, compressing the refuse repeatedly on alternate sides of the container. In one version of the device, the crank arm and the paddle are aligned in identical angular orientations and the cylinders push in unison to compress the refuse.

Abstract: A manually operable pressure relief valve for swimming pool filter systems and the like, including a valve housing, a valve stem movable axially in the housing to open and close the valve, and a top cover that serves as an operating handle. The valve housing and the valve stem have components that cooperate to provide an axial movement from closed to fully open with only a quarter turn of the stem, and to prevent inadvertent removal of the stem from the housing. The stem must be moved deliberately through a sequence of required rotational and axial displacements to remove it. The top cover must also be manipulated in a prescribed manner to effect removal of the stem from the housing.

Abstract: A technique for removing particles from above a semiconductor wafer, particularly particles that are trapped in a plasma chamber during processing of the wafer. Trapped particles are usually not all drawn out with gases exhausted from the chamber, in part because a peripheral focus ring and clamping mechanism impede their flow. In the method of the invention, the focus ring and clamping mechanism are raised on completion of processing, but before radio-frequency (rf) power is disconnected from the process chamber. Trapped particles are then easily flowed from the chamber with an introduced inert gas, and the level of particulate contamination of the wafer is significantly reduced.

Abstract: A method for reducing targeting errors encountered when trying to locate contaminant particles in a high-magnification imaging device, based on estimates of the particle positions obtained from a scanning device. The method of the invention includes scanning a semiconductor wafer in a scanning device, then preferably moving the wafer to a different orientation, and scanning the wafer again, to obtain at least two sets of particle coordinates that may differ slightly because of uncertainties in the scanning process. The multiple sets of coordinates are averaged to reduce the targeting errors, but only after transforming the coordinates to a common coordinate system. The transformation step includes computing transformation parameters for each possible pair of particles detected in at least two scans, averaging the results, and then transforming all of the particle coordinates to the common coordinate system.

Abstract: A technique for establishing and maintaining full duplex communication between two stations connected to a token ring network, without physically reconfiguring the station connections or otherwise disturbing the network. Each station continually performs a two node test to ascertain whether there are only two active stations on the network, and updates a two node flag that indicates whether or only two active stations are present. The two node test uses both upstream neighbor and downstream neighbor addresses to update the two node flag, and requires validation of either one of these addresses if the other one of them appears to have changed since the previous observation. A concurrently running full duplex control process uses the two node flag and other conditions to decide whether to initiate or continue transition to full duplex mode.

Abstract: A technique for controlling access to a bridge connected to at least two networks, such that network collisions are reduced, transmit live-lock conditions are eliminated, and buffer memory requirements are minimized. For at least one target network of the two networks, two dynamic lists are maintained, to keep track of data packets received from the target network and not yet forwarded, and to keep track of data packets stored for forwarding to the target network, but not yet forwarded. The target network uses a half-duplex medium and a CSMA/CD (Carrier Sense Multiple Access with Collision Detection) protocol. The invention operates by dynamically adjusting an inter packet gap (IPG) betweens data packets forwarded to the target network, such that stations on the target network are, under selected conditions, given an extended opportunity to transmit.

Abstract: Apparatus, and a corresponding method for it use, for directly modulating an optical carrier with a radio-frequency (rf) electrical signal. A semiconductor electroabsorptive modulator is operated at an optical wavelength and electrical bias voltage carefully selected to provide a near-linear electrical-to-optical transfer characteristic and to keep rf insertion loss low. Further reduction of insertion loss is achieved by use of an extremely short device, or a single quantum well device configuration, or both. Linearity is further optimized by choosing an appropriate combination of optical polarization mode, optical reflectivity of the device facets, and the number and physical properties of multiple quantum wells.

Abstract: Apparatus, and a corresponding method for its operation, for controlling the air/fuel ratio in a large engine having one or more banks of cylinders with separate intake and exhaust manifolds. Oxygen sensors in the manifolds are sampled periodically to provide the apparatus with an indication of the level of oxygen, and therefore an indication of the level of various pollutants, in exhaust gases discharged from the engine. The apparatus, preferably in microprocessor form, computes a fuel control correction based on the difference between the sensed oxygen level and a desired oxygen level in each exhaust manifold. The correction is applied in the form of a change to the pulse width of a binary control signal applied to a solenoid valve. In the illustrative embodiment, the solenoid valve is coupled to a fuel pressure regulator and functions to vent an air chamber in the regulator when the solenoid is actuated.

Abstract: A highly versatile data search engine in which multiple search cells are connected together in a pipeline through which data can be streamed. Each cell has multiple registers, and corresponding registers in each cell are connected together to form the pipeline. Characters in two data streams are compared in the pipeline, a first data stream that includes a sequence of database characters and parallel sequences of associated data, and a second data stream that includes a sequence of pattern characters and parallel sequences of associated data. The parallel data sequences associated with the pattern data include coded signals that control cell operation. One of the parallel data sequences associated with the database is a sequence of character marks, which are used to indicate search starting points in the database character sequence, and which are propagated along the database character sequence as a result of successive character matches between the pattern and database characters.

Abstract: A compact assembly of two magnetic couplers for coupling two coaxial angular shaft movements through a vacuum barrier. Each coupler includes two concentric rings of radially oriented magnets, arranged to provide magnetic coupling in a radial direction between corresponding magnets in the rings. A relatively large number of magnets in each ring ensures stiff coupling between rings, but unwanted circumferential coupling between adjacent magnets in each ring is minimized by the presence of a flux ring associated with each ring of magnets. The flux rings provide a return path for radial magnetic flux lines between the rings. Cross-coupling between the couplers is minimized by the presence of a magnetic shield on each ring of magnets. The shields permit the couplers to be located in close proximity on their common axis of rotation. For corrosion resistance, each ring of magnets on the vacuum side of the barrier is housed in a stainless steel enclosure.

Abstract: A combined wafer support and thermocouple assembly comprising a wafer support basket having a plurality of wafer support fingers, one of which includes a low mass, low heat constant support for supporting a thermocouple against the backside of a wafer positioned on the basket.

Abstract: A robot having a pair of magnetic couplings that each couple a motor in a cylindrical first chamber to an associated cylindrical ring closely spaced from the cylindrical wall of said first chamber. The robot includes a mechanism to convert rotation of each of these rings into separate motions of the robot. In the preferred embodiment, these separate motions are radial and rotational.

Abstract: A suction fitting for use in a water circulation system, the fitting having a perforated body that is mounted to permit fluid flow through both front and rear perforated faces, and thereby minimize the possibility of complete blockage of the fitting by entrapped hair or skin. Operation of a circulating pump is controlled to prevent damage to equipment and property and also to minimize the possibility of serious personal injury or death. The suction fitting further includes a suction tube for connection to the pump, for circulating water in the tub or spa back through jets in the tub or spa, and a pressure sensor line connecting the water in the tub or spa to a water level sensor. The front face of the perforated body has a number of grooves, to provide fluid communication between the pressure sensor line and the suction tube, through one or more front-face perforations.