Leland Stanford Junior University

Other

Thomas Kailath

Hamid K Aghajan

Arogyaswami J Paulraj

Charles Daniel Schaper

Richard H Roy, Iii

Yagyensh C Pati

R Fabian Pease

Mark A McCord

Xun Chen

Babak H Khalaj

Khalid A El-Awady

Todd K Citron

Khalid El-Awady

Amir A Ghazanfarian

Tiejun J Shan

A module for thermally processing a substrate has a plurality of thermally-conductive heating elements supported in position within a plane. Resistive heaters in the form of cartridge heaters are in thermal contact with the heating elements. Multiple zones are enabled by physical separation of the heating elements that constitute the thermal processing plate. A cooling plate is positioned in proximity to the backside of the heating elements and can be driven into thermal contact with the upper heated plate when cooing is desired.

Temperature processing module

Systems, methods and computer program products detect a position of a new alignment mark on a substrate by producing an alignment signal model from sample alignment signals and fitting the new alignment signal to the alignment signal model. The alignment signal model may be produced from the multiple sample alignment signals using singular value decomposition, based on subspace decomposition of the alignment signals. By producing an alignment signal model from multiple sample alignment signals, asymmetries in the sample alignment marks and/or in the coatings that are fabricated on the sample alignment marks, may be taken into account when detecting the position of a new alignment mark.

Systems, methods and computer program products for detecting the

A thermal cycling module includes an array of thermoelectric devices �36! divided into multiple zones �A, B, C, D! independently controlled by corresponding variable power supplies �56, 58, 60, 62!. The thermoelectric devices �36! provide localized, precise, and rapid control of both heating and cooling, while fluid from one of several fluid supplies �64, 66, 68! provides bulk heating or cooling via a fluid heat exchanger �38!. Sensors �46, 48, 50, 52! provide feedback of temperature or other process parameters to a controller �54! which generates control signals for controlling the power supplies �56, 58, 60, 62!, the fluid supplies �64, 66, 68!, and fluid valves �70, 72! which control fluid flow through the heat exchanger �38!.

Multizone bake/chill thermal cycling module

Disclosed is a fast and high resolution technique for estimating the skew angle in text document images. Detection of the skew angle is an important step in text processing tasks such as optical character reading (OCR) and computerized filing. The proposed method is based on the application of a recently developed algorithm for estimation of angle of straight lines in a scanned image. The Subspace-Based Line Detection (SLIDE) algorithm formulates the multi-line fitting problem in a special parameter estimation framework such that a signal structure similar to the one in the field of high-resolution sensor array processing is obtained. Then the well-studied techniques in that formalism (e.g., the ESPRIT algorithm) are exploited to produce closed-form and high resolution estimates for line parameters.

Estimation of skew angle in text image

A systematic method of producing a mask for use within a photolithographic illumination system characterized by a transmission function in which light is transmitted through non-opaque portions of the mask positioned in an object plane and in which an image is formed on an image plane is disclosed herein. The method includes the steps of defining a binary image pattern to be formed by the illumination system on the image plane; generating a continuous mask function of continuously-varying phase which satisfies predetermined error criteria based on the transmission function and the binary image pattern; transforming the mask function into a quadrature-phase mask function by dividing the continuously-varying phase into four phase levels; and generating the mask in accordance with the quadrature-phase mask function, wherein the mask includes a plurality of pixel regions each of which has a transmittance corresponding to one of the four phase levels.

Systematic method for production of phase-shifting photolithographic

Disclosed is a new self-reference signal processing technique for detecting the location of any nonregularities and defects in a periodic two-dimensional signal or image. Using high-resolution spectral estimation algorithms, the proposed technique first extracts the period and structure of repeated patterns from the image to sub-pixel resolution in both directions, and then produces a defect-free reference image for making comparison with the actual image. Since the technique acquires all its needed information from a single image, on the contrary to the existing methods, there is no need for a database image, a scaling procedure, or any apriori knowledge about the repetition period of the patterns.

Automated direct patterned wafer inspection

A new signal processing method solves the problem of fitting multiple lines in a two-dimensional image. The Subspace-Based Line Detection (SLIDE) algorithm formulates the multi-line fitting problem in a special parameter estimation framework such that a signal structure similar to the sensor array processing signal representation is obtained. Any spectral estimation method can then be exploited to obtain estimates of the line parameters. In particular, subspace-based algorithms of sensor array processing (e.g., the ESPRIT technique) can be used to produce closed-form and high resolution estimates for line parameters. The signal representation employed in this formulation can be generalized to handle both problems of line fitting (in which a set of binary-valued discrete pixels is given) and of straight edge detection (in which one starts with a grey-scale image).

Subspace-based line detection

A method and apparatus for increasing the capacity of wireless broadcast communications system from a central studio to a plurality of users in a service area is disclosed. Given a source signal whose high information rate exceeds the practical information carrying capacity of the available broadcast channel bandwidth, the invention increases the effective capacity of the broadcast system to effectively communicate such a source signal. The high-rate signal is split into several low-rate signals such that each can be accommodated within the allocated bandwidth. These low-rate signals are transmitted from spatially separated transmitters, all radiating into the service area in the same frequency channel. Each receiver uses a plurality of antennas to receive these multiple cochannel signals that arrive from different directions-of-arrival. The receiver exploits the directions-of-arrival differences of these cochannel signals to separate them into the individually transmitted signals. The separated signals are then demodulated to extract the information signals which are then combined to obtain the original high-rate source signal. Thus, the broadcast information capacity can be increased several-fold.

Increasing capacity in wireless broadcast systems using distributed

An image processor employing a camera, frame grabber and a new algorithm for detecting straight edges in optical images is disclosed. The algorithm is based on using a self-organizing unsupervised neural network learning to classify pixels on a digitized image and then extract the corresponding line parameters. The image processor is demonstrated on the specific application of edge detection for linewidth measurement in semiconductor lithography. The results are compared to results obtained by a standard straight edge detector based on the Radon transform; good consistency is observed; however, superior speed is achieved for the proposed image processor. The results obtained by the proposed approach are also shown to be in agreement with Scanning Electron Microscope (SEM) measurements, which is known to have excellent accuracy but is an invasive measurement instrument. The method can thus be used for on-line measurement and control of microlithography processes and for alignment tasks as well.

Method of edge detection in optical images using neural network

The invention described herein relates generally to the field of signal processing for signal reception and parameter estimation. The invention has many applications such as frequency estimation and filtering, and array data processing, etc. For convenience, only applications of this invention to sensor array processing are described herein. The array processing problem addressed is that of signal parameter and waveform estimation utilizing data collected by an array of sensors. Unique to this invention is that the sensor array geometry and individual sensor characteristics need not be known. Also, the invention provides substantial advantages in computations and storage over prior methods. However, the sensors must occur in pairs such that the paired elements are identical except for a displacement which is the same for all pairs. These element pairs define two subarrays which are identical except for a fixed known displacement. The signals must also have a particular structure which in direction-of-arrival estimation applications manifests itself in the requirement that the wavefronts impinging on the sensor array be planar. Once the number of signals and their parameters are estimated, the array configurations can be determined and the signals individually extracted. The invention is applicable in the context of array data processing to a number of areas including cellular mobile communications, space antennas, sonobuoys, towed arrays of acoustic sensors, and structural analysis.

Methods and arrangements for signal reception and parameter estimation

The invention relates generally to the field of signal processing for signal reception and parameter estimation. The invention has many applications such as frequency estimation and filtering, and array data processing, etc. For convenience, only applications of this invention to sensor array processing are described herein. The array processing problem addressed is that of signal parameter and waveform estimation utilizing data collected by an array of sensors. Unique to this invention is that the sensor array geometry and individual sensor characteristics need not be known. Also, the invention provides substantial advantages in computations and storage over prior methods. However, the sensors must occur in pairs such that the paired elements are identical except for a displacement which is the same for all pairs. These element pairs define two subarrays which are identical except for a fixed known displacement. The signals must also have a particular structure which in direction-of-arrival estimation applications manifests itself in the requirement that the wavefronts impinging on the sensor array be planar. Once the number of signals and their parameters are estimated, the array configuration can be determined and the signals individually extracted. The invention is applicable in the context of array data processing to a number of areas including cellular mobile communications, space antennas, sonobuoys, towed arrays of acoustic sensors, and structural analysis.

Method for estimating signal source locations and signal parameters

A method and processing matrix for detection and correction of errors in coded data based on determining the error location and error evaluator polynomials using the relationship defined by the key equation. A systolic processor is disclosed which utilizes pipelining and a regular, parallel structure based on a derived algorithm for solving the key equation.

Method and means for error detection and correction in high speed data

Suppression of coherent and non-coherent interferring signals is obtained by a smoothing operation in an adaptive signal processing array by providing a plurality of signal detectors and a plurality of variable weighting means for weighting signals from each of the detectors. The weighting means are grouped in overlapping sub-groups of less than all of the plurality of weighing means and the weighted signals from each sub-group are summed. The summed weighted signals of each sub-group are then operated on by an adaptive algorithm to obtain a feedback signal that is applied to adjust the variable weighting means.

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Stanford, CA, United States of America

Thomas Kailath