Preprocessing of image amplitude and phase data for CD and OL measurement

An optical measuring method for measuring a pattern on a substrate with the output of an optical imaging system, amplitude and phase imaging for narrow angle, single wavelength, polarized illumination in a coherence probe type of interferometric microscope system, said microscope system including a microprocessor providing signals derived from said amplitude and phase imaging, comprising:

• deriving raw interferometer fringe amplitude and phase data from said microprocessor,
• converting said fringe amplitude and phase data into amplitude and phase data,
• deriving a fourier transform of said amplitude and phase data, and
• applying corrections to said transformed data to provide corrected data,
• selecting image type and then deriving the air inverse transform from said corrected data and processing to provide amplitude and phase image data as a first image output, and
• bright field image processing to provide a second image output, and
• dark field image processing to provide a third image output, and
• processing the corrected phase image data to provide a fourth image output,
• processing the corrected amplitude to provide a fifth image output, and measuring a value selected from the group consisting of critical dimension and overlay from one of said image outputs.

An imaging system for a pattern on a substrate, comprising:

• means for amplitude and phase imaging for narrow angle, single wavelength, polarized illumination in an interferometric microscope system,
• said microscope system including a microprocessor providing signals derived from said amplitude and phase imaging,
• means for deriving raw interferometer fringe data from said microprocessor,
• means for converting said fringe data into amplitude and phase data,
• means for deriving the fourier transform of said amplitude and phase data,
• means for applying corrections to said transformed data to provide corrected data,
• means for selecting image type and then means for deriving the inverse transform from said corrected data and processing to provide amplitude and
• means for providing data selected from the group consisting of as follows:
• a) phase image data as a first image output,
• b) bright field image data as a second image output,
• c) dark field image data as a third image output, and
• d) the corrected phase image data as a fourth image output, and
• e) corrected amplitude to provide a fifth image output.

An optical measuring method for measuring a pattern on a substrate with the output of an optical imaging system, amplitude and phase imaging for narrow angle, single wavelength, polarized illumination in a coherence probe type of interferometric microscope system, said microscope system including a microprocessor providing signals derived from said amplitude and phase imaging, comprising:

• deriving raw interferometer fringe amplitude and phase data from said microprocessor,
• converting said fringe amplitude and phase data into amplitude and phase data,
• deriving a fourier transform of said amplitude and phase data, and
• applying corrections to said transformed data to provide corrected transformed data,
• providing data selected from the group consisting of as follows:
• a. selecting an image type and then deriving an inverse transform from said corrected data and processing to provide corrected amplitude data and providing corrected phase image data as a first image output,
• b. bright field image processing to provide a second image output,
• c. dark field image processing to provide a third image output,
• d. processing of the corrected phase image to provide a fourth image output, and
• e. processing of said corrected amplitude data to provide a fifth image output, and measuring critical dimension or overlay from one of said first, second, third, fourth and fifth image outputs.