Abstract:
A method of extracting a feature from a data set includes iteratively extracting a feature 244 from a data set based on a visualization 238 of a residual pattern comprised within the data set, wherein the feature is distinct from a feature extracted in a previous iteration, and the visualization of the residual pattern uses the feature extracted in the previous iteration. Visualizing 234 the data set using the feature extracted in the previous iteration may comprise showing residual patterns of attribute data that are relevant to target data. Visualizing 234 the data set using the feature extracted in the previous iteration may involve adding cluster constraints to the data set, based on the feature extracted in the previous iteration. Additionally or alternatively, visualizing 234 the data set using the feature extracted in the previous iteration may involve defining conditional probabilities conditioned on the feature extracted in the previous iteration.
Abstract:
A computer implemented method for diagnosing a system comprising a plurality of modules. The method comprises: receiving a causal graph, the causal graph defining (i) a plurality of nodes each representing a module of the system , wherein each module is characterized by one or more signals; and (ii) edges connected between the nodes, the edges representing propagation of performance between modules; generating a reasoning tool by augmenting the causal graph with diagnostics knowledge based on historically determined relations between performance, statistical and causal characteristics of at least one module out of the plurality of modules; obtaining a health metric of the at least one module, wherein the health metric is associated with the one or more signals associated with the at least one module; and using the health metric as an input to the reasoning tool to identify a module that is the most likely cause of the behaviour.
Abstract:
Disclosed is a method of tuning a prediction model relating to at least one particular configuration of a manufacturing device. The method comprises obtaining a function comprising at least a first function of first prediction model parameters associated with said at least one particular configuration, and a second function of the first prediction model parameters and second prediction model parameters associated with configurations of the manufacturing device and/or related devices other than the at least one particular configuration. Values of the first prediction model parameters are obtained based on an optimization of the function, and a prediction model is tuned according to these values of the first prediction model parameters to obtain a tuned prediction mode.
Abstract:
The invention generates predicted data for control or monitoring of a production process to improve a parameter of interest. Context data 502 associated with operation of the production process 504 is obtained. Metrology/test 508 is performed on the product 506 of the production process 504, thereby obtaining performance data 510. A context-to-performance model is provided to generate predicted performance data 526 based on labeling of the context data 502 with performance data. This is an instance of semi-supervised learning. The context-to-performance model includes the learner 522 that performs semi-supervised labeling. The context-to-performance model is modified using prediction information related to quality of the context data and/or performance data. Prediction information may comprise relevance information relating to relevance of the obtained context data and/or obtained performance data to the parameter of interest. The prediction information may comprise model uncertainty information relating to uncertainty of the predicted performance data.
Abstract:
A lithographic process is performed on a plurality of semiconductor wafers (900; 1020). The method includes selecting one or more of the wafers as sample wafers (910-914; 1030-1034). Metrology steps (922; 1042) are performed only on the selected sample wafers. Based on metrology results (924; 1046) of the selected sample product units corrections are defined for use in controlling processing of the wafers or future wafers. The selection of sample product units is based at least partly on statistical analysis of object data (902; 1006) measured in relation to the wafers. The same object data or other data can be used for grouping wafers into groups. Selecting of sample wafers can include selecting wafers (910-914; 1030-1034) that are identified by said statistical analysis as most representative of the wafers in their group. The selecting of sample wafers can include elimination of product units (916; 1036) that are identified as unrepresentative.
Abstract:
Disclosed is a method of determining a correction for a process parameter related to a lithographic process on a substrate and associated apparatuses. The lithographic process comprises a plurality of runs during each one of which a pattern is applied to one or more substrates. The method comprises obtaining pre-exposure metrology data describing a property of the substrate; obtaining post-exposure metrology data comprising one or more measurements of the process parameter having been performed on one or more previously exposed substrates; assigning to the substrate, a class membership status from a plurality of classes, based on said pre-exposure metrology data; and determining the correction for the process parameter based on said class membership status and said post-exposure metrology data.
Abstract:
A fault in a subject production apparatus which is suspected of being a deviating machine, is identified based on whether it is possible to train a machine learning model to distinguish between first sensor data derived from the subject production apparatus, and second sensor data derived from one or more other production apparatuses which are assumed to be behaving normally. Thus, the discriminative ability of the machine learning model is used as an indicator to discriminate between a faulty machine and the population of healthy machines.
Abstract:
Method and apparatus for adapting a distribution model of a machine learning fabric. The distribution model is for mitigating the effect of concept drift, and is configured to provide an output as input to a functional model of the machine learning fabric. The functional model is for performing a machine learning task. The method comprises obtaining a first data point, and providing the first data point as input to one or more distribution monitoring components of the distribution model. The one or more distribution monitoring components have been trained on a plurality of further data points. A metric representing a correspondence between the first data point and the plurality of further data points is determined, by at least one of the one or more distribution monitoring components. Based on the error metric, the output of the distribution model is adapted.