Accent Optical Technologies, Inc.

Nanometrics Inc.

Christopher J Raymond

Michael E Littau

Scott Richard Wilson

Andrzej Buczkowski

Steve W Farrer

Richard H Krukar

A method and apparatus identifies defects in a sample using photoluminescence with a silicon filter to filter out the primary excitation light from the return light received by the detector. The silicon filter passes the light emitted by the sample in response to the excitation light, while absorbing the lower wavelength excitation light that is reflected by or transmitted through the sample. The silicon filter has introduced impurities that reduce the recombination lifetime which reduces or eliminate photoluminescence in the silicon filter in response to the excitation light, thereby improving the signal to noise ratio of the signal received by the detector.

Silicon filter for photoluminescence metrology

This disclosure provides methods for measuring asymmetry of features, such as lines of a diffraction grating. On implementation provides a method of measuring asymmetries in microelectronic devices by directing light at an array of microelectronic features of a microelectronic device. The light illuminates a portion of the array that encompasses the entire length and width of a plurality of the microelectronic features. Light scattered back from the array is detected. One or more characteristics of the back-scattered light may be examined by examining data from the complementary angles of reflection. This can be particularly useful for arrays of small periodic structures for which standard modeling techniques would be impractically complex or take inordinate time.

Line profile asymmetry measurement

This disclosure provides methods for measuring asymmetry of features, such as lines of a diffraction grating. On implementation provides a method of measuring asymmetries in microelectronic devices by directing light at an array of microelectronic features of a microelectronic device. The light illuminates a portion of the array that encompasses the entire length and width of a plurality of the microelectronic features. Light scattered back from the array is detected. One or more characteristics of the back-scattered light may be examined by examining data from complementary angles of reflection. This can be particularly useful for arrays of small periodic structures for which standard modeling techniques would be impractically complex or take inordinate time.

Methods for the determination of center of focus and process control for a lithographic tool. Diffraction signatures are obtained from a plurality of diffraction structures located within multiple different focus setting fields. Variability of diffraction signatures with each field are determined, by direct analysis or comparison to a library. The variation or uniformity may be represented by any measure, including the standard deviation or the range of values of a chosen feature of a library of theoretical diffraction structures or the variability or uniformity of the diffraction signatures themselves, such as by RMS difference or intensity range. The methods may be used for process control and monitoring of focus drift by determining intra-field variation of diffraction signatures of multiple diffraction structures in a series of wafers.

Determination of center of focus by parameter variability analysis

Methods for determination of parameters in lithographic devices and applications by cross-section analysis of scatterometry models, including determination of center of focus in lithography devices and applications. Control methods are provided for process control of center of focus in lithography devices utilizing cross-section analysis.

Determination of center of focus by cross-section analysis

A method of and apparatus for measuring line profile asymmetries in microelectronic devices comprising directing light at an array of microelectronic features of a microelectronic device, detecting light scattered back from the array comprising either or both of one or more angles of reflection and one or more wavelengths, and comparing one or more characteristics of the back-scattered light by examining data from complementary angles of reflection or performing a model comparison.

Line profile asymmetry measurement using scatterometry

A method of pruning a reference library of signatures and corresponding known structure parameter vectors, each signature composed of a reference signal vector, including, for a given reference signal vector, interpolating a parameter vector and deleting the given reference signal vector and the corresponding parameter vector for a sufficiently small interpolation error. Also a method of accessing an indexed reference library of signatures and corresponding known structure parameter vectors, each signature comprising a reference signal vector, including acquiring an unknown signal, calculating an index vector for the unknown signal; determining error between the index vector for the unknown signal and a calculated reference signal index vector of the library; and thereby identifying as a match candidate for the unknown signal a reference signal vector.

Structure identification using scattering signatures

Methods for determination of parameters in lithographic devices and applications by diffraction signature difference analysis, including determination of center of focus in lithography devices and applications. Latent image analysis may be employed with exposed but undeveloped lithographic substrates. Control methods are provided for process control of center of focus in lithography devices utilizing diffraction signature difference analysis.

Determination of center of focus by diffraction signature analysis

The present invention provides methods for determination of parameters in lithographic devices and applications by diffraction signature difference analysis, including determination of center of focus in lithography devices and applications.

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Albuquerque, NM, United States of America

Christopher J Raymond