General Dynamics Corp., Pomona Division

Other

William R Yueh

Philip T Kan

Endpoint determination of a wafer removal process, in-situ, is afforded by the use of a Kalman filter known to be useful in celestial navigation. The use of line variable displacement transducers provides position error correction for the Kalman filter and the Preston equation provides the initial calibration for the endpoint determination. Accuracies of fifty angstrom are achieved.

In-situ endpoint control apparatus for semiconductor wafer polishing

A slurry recycling system for a chemical-mechanical polishing apparatus includes an annular-shaped wafer polishing platen which rotates about a non-rotating center core. A slurry dispensing system housed in the center core directs a slurry mist radially into the path of a moving wafer. The recycling system is positioned at the periphery of the platen and is controlled by an end point monitoring and control system which uniquely provides instantaneous wafer removal rate data to regulate a slurry recycling valve.

Slurry recycling system for chemical-mechanical polishing apparatus

Semiconductor wafer polishing apparatus, in accordance with the princples of this invention, includes an annular-shaped platen rotatable about a non-rotating center core having a diameter smaller than the width of the annular-shaped platen. The center core is the source of slurry which permits convenient dispensing of slurry. The apparatus includes a bridge which extends from the center core to the rigid table in which the apparatus is housed. The bridge is a convenient support for apparatus for pad rejuvenation and for sensing and correcting wafer attitude and characteristics as well as slurry properties on a real time basis for improving wafer uniformity and local surface planarity.

Semiconductor wafer polishing apparatus

An apparatus for detecting deflection of the spin axis of a gimbal supported spinning mass relative to the gimbal axis comprises four equally spaced linear arrays of detector elements mounted around the gimbal axis and extending parallel to that axis. Four light sources are provided, each one in alignment with a respective one of the arrays, and a reflective surface is provided on the spinning mass for reflecting light onto the respective detector arrays. Deflection of the spin axis will be registered by displacement of a reflected light spot in one or more of the arrays.

Gimbal angle detector

A method and apparatus for identifying inertial reference unit (IRU) errors in a guided missile employing a multi-mode guidance system and constructing correction terms to recover the missile true position. Discrepancy parameters are introduced to indicate misalignment between missile and launching platform (or ship) inertial frames where the missile onboard executive computer simultaneously processes the data provided from missile onboard sensors and target relevant data uplinked from the launching platform. The discrepancy parameters are employed to construct correction factors used to reduce the discrepancies. This updated missile configuration is then coupled with the target state estimator outputs to reconstruct smoothed line-of-sight (LOS) angles for terminal homing engagement.

Self-adaptive IRU correction loop design interfacing with the target

A method for augmenting a noise-adaptive predictive proportional navigation terminal guidance scheme. In a third order configuration with noise adaptive varying gain parameters calculated as a function of time-to-go, this system implements an optimal control law to augment proportional navigation with a target acceleration feed forward term and a navigation ratio which is a function of time-to-go and the control effort weighting factor. This third order system may also implement another optimal control law to even greater advantage, taking into account not only target acceleration but also missile acceleration in a feedback loop which, together with the navigation ratio, are both functions of time-to-go and autopilot dynamics, whereby first order autopilot time lag is accounted for. This system is particularly useful for high and medium altitude targets and results in significant miss distance improvement for terminal guidance against small maneuvering targets.

Augmented proportional navigation in third order predictive scheme

A method for augmenting a noise-adaptive predictive proportional navigation terminal guidance scheme. In a fourth order configuration with noise adaptive varying gain parameters calculated as a function of time-to-go, this system implements an optimal control law to augment proportional navigation with target and missile information terms and a navigation ratio which is a function of time-to-go. By employing a fourth order system, enhanced use may be made of information already available in the guidance computer and missile control system to decouple target motion information from the missile control signals. Decoupled target motion information facilitates blind-mode operation in the end game, the last few seconds before intercept. Decoupled missile control information enables the airframe to be controlled to predefined orientations for aimed warhead applications. This system is particularly useful for high and medium altitude targets and results in significant miss distance improvement for terminal guidance against small maneuvering targets. The system has additional benefits in that it results in nearly optimal miss distance behavior with sensitivity to unmodeled errors being substantially less than that in modern guidance systems.

Fourth order predictive, augmented proportional navigation system

A method for augmenting the value of range uplink information in a predictive proportional navigation terminal guidance scheme. A second order configuration, with noise adaptive varying gain parameters calculated as a function of time-to-go, is particularly useful for high altitude, minimally maneuvering targets. This configuration results in acceptable miss distances, better than conventional proportional navigation, with sensitivity to unmodeled errors being substantially less than that in modern guidance systems. A third order configuration makes enhanced use of range uplink information to provide improved terminal guidance against lower altitude maneuvering targets. The sensitivity of the third order configuration is similar to that of conventional proportional navigation but with better miss distance results.

Noise-adaptive, predictive proportional navigation (NAPPN) guidance

A method for augmenting a noise-adaptive predictive proportional navigation terminal guidance scheme. In a second order configuration with noise adaptive varying gain parameters calculated as a function of time-to-go, this system implements an optimal control law to augment proportional navigation with a missile acceleration feedback term and a navigation ratio to account for first order autopilot time lag. This configuration results in nearly optimal miss distance behavior, with sensitivity to unmodeled errors being substantially less than that in modern guidance systems. The system is particularly useful for high altitude, minimally maneuvering targets.

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Claremont, CA, United States of America

William R Yueh