Abstract: An overlay metrology system may include a controller for receiving metrology data associated with a plurality of overlay targets on one or more samples; generating a reference metric for at least some of the plurality of overlay targets based on the metrology data, where the reference metric is associated with one or more properties of the respective overlay targets that contributes to overlay error; classifying the plurality of overlay targets into one or more groups based on the reference metrics calculated for the plurality of overlay targets; generating a reference image for at least some of the one or more groups; generating corrected metrology data using the associated reference image for at least some of the one or more groups; and generating overlay measurements for the plurality of overlay targets based on the corrected metrology data.

Abstract: Systems and methods of optimizing wafer transport and metrology measurements in a fab are provided. Methods comprise deriving and updating dynamic sampling plans that provide wafer-specific measurement sites and conditions, deriving optimized wafer measurement paths for metrology measurements of the wafers that correspond to the dynamic sampling plan, managing FOUP (Front Opening Unified Pod) transport through the fab, transporting wafers to measurement tools while providing the dynamic sampling plans and the wafer measurement paths to the respective measurement tools before or as the FOUPs with the respective wafers are transported thereto, and carrying out metrology and/or inspection measurements of the respective wafers by the respective measurement tools according to the derived wafer measurement paths.

Abstract: Systems and methods of optimizing wafer transport and metrology measurements in a fab are provided. Methods comprise deriving and updating dynamic sampling plans that provide wafer-specific measurement sites and conditions, deriving optimized wafer measurement paths for metrology measurements of the wafers that correspond to the dynamic sampling plan, managing FOUP (Front Opening Unified Pod) transport through the fab, transporting wafers to measurement tools while providing the dynamic sampling plans and the wafer measurement paths to the respective measurement tools before or as the FOUPs with the respective wafers are transported thereto, and carrying out metrology and/or inspection measurements of the respective wafers by the respective measurement tools according to the derived wafer measurement paths.

Abstract: A method of determining overlay (“OVL”) in a pattern in a semiconductor wafer manufacturing process comprises capturing images from a cell in a metrology target formed in at least two different layers in the wafer with parts of the target offset in opposing directions with respect to corresponding parts in a different layer. The images may be captured using radiation of multiple different wavelengths, each image including +1 and ?1 diffraction patterns. A first and second differential signal may be determined for respective pixels in each image by subtracting opposing pixels from the +1 and ?1 diffraction orders for each of the multiple wavelengths. An OVL for the respective pixels may be determined based on analyzing the differential signals from multiple wavelengths simultaneously. Then an OVL for the pattern may be determined as a weighted average of the OVL of the respective pixels.

Abstract: A method of determining overlay (“OVL”) in a pattern in a semiconductor wafer manufacturing process comprises capturing images from a cell in a metrology target formed in at least two different layers in the wafer with parts of the target offset in opposing directions with respect to corresponding parts in a different layer. The images may be captured using radiation of multiple different wavelengths, each image including +1 and ?1 diffraction patterns. A first and second differential signal may be determined for respective pixels in each image by subtracting opposing pixels from the +1 and ?1 diffraction orders for each of the multiple wavelengths. An OVL for the respective pixels may be determined based on analyzing the differential signals from multiple wavelengths simultaneously. Then an OVL for the pattern may be determined as a weighted average of the OVL of the respective pixels.

Abstract: Methods applicable in metrology modules and tools are provided, which enable adjusting metrology measurement parameters with respect to process variation, without re-initiating metrology recipe setup. Methods comprise, during an initial metrology recipe setup, recording a metrology process window and deriving baseline information therefrom, and during operation, quantifying the process variation with respect to the baseline information, and adjusting the metrology measurement parameters within the metrology process window with respect to the quantified process variation. The quick adjustment of metrology parameters avoids metrology-related process delays and releases prior art bottlenecks related thereto. Models of effects of various process variation factors on the metrology measurements may be used to enhance the derivation of required metrology tuning and enable their application with minimal delays to the production process.

Abstract: A method of overlay control in silicon wafer manufacturing comprises firstly locating a target comprising a diffraction grating on a wafer layer; and then measuring the alignment of patterns in successive layers of the wafer. The location of the target may be done by the pupil camera rather than a vision camera by scanning the target to obtain pupil images at different locations along a first axis. The pupil images may comprise a first order diffraction pattern for each location. A measurement of signal intensity in the first order diffraction pattern is then obtained for each location. The variation of signal intensity with location along each axis is then analyzed to calculate the location of a feature in the target.

Abstract: Methods applicable in metrology modules and tools are provided, which enable adjusting metrology measurement parameters with respect to process variation, without re-initiating metrology recipe setup. Methods comprise, during an initial metrology recipe setup, recording a metrology process window and deriving baseline information therefrom, and during operation, quantifying the process variation with respect to the baseline information, and adjusting the metrology measurement parameters within the metrology process window with respect to the quantified process variation. The quick adjustment of metrology parameters avoids metrology-related process delays and releases prior art bottlenecks related thereto. Models of effects of various process variation factors on the metrology measurements may be used to enhance the derivation of required metrology tuning and enable their application with minimal delays to the production process.

Abstract: A method of overlay control in silicon wafer manufacturing comprises firstly locating a target comprising a diffraction grating on a wafer layer; and then measuring the alignment of patterns in successive layers of the wafer. The location of the target may be done by the pupil camera rather than a vision camera by scanning the target to obtain pupil images at different locations along a first axis. The pupil images may comprise a first order diffraction pattern for each location. A measurement of signal intensity in the first order diffraction pattern is then obtained for each location. The variation of signal intensity with location along each axis is then analyzed to calculate the location of a feature in the target.