Method of Analyzing Metrology Data
AssigneeBruker Nano, Inc.
InventorsVladimir Fonoberov, Sean Hand, David Fey
Life of this patent
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Abstract
The preferred embodiments are directed to a metrology method used, for example, in recess analysis in semiconductor fabrication that includes using atomic force microscopy (AFM) data of a sample having an array of 2D-periodic features to generate a sample image, and calculating a periodicity of the features. The method identifies the peaks in the periodicity to determine a feature period and a lattice angle, and constructs a lattice mask that is registered to the image to perform an alignment calculation. The mask is offset, and alignment calculation made, to optimize cost.
Claims20
A metrology method comprising the steps of:
- using atomic force microscopy (AFM) data of a sample having an array of periodic features to generate a sample image having feature pixels and background pixels;
- calculating a periodicity of the features;
- identifying peaks in the periodicity to determine a feature period and a lattice angle;
- constructing a lattice mask template using the feature period and the lattice angle;
- overlaying the image with the lattice mask template;
- performing an alignment calculation to determine a cost;
- applying an offset of the lattice mask template to the image and recalculating the cost;
- and
- repeating the applying and the recalculating steps to determine an alignment between the lattice mask template and the image.
A metrology method comprising the steps of:
- generating an image of a sample using atomic force microscopy (AFM) data;
- calculating a periodicity of features of the image;
- searching for at least one peak in the periodicity;
- obtaining a feature period and a lattice angle;
- constructing a lattice mask template using the feature period and the lattice angle;
- overlaying the image with the lattice mask template;
- performing an alignment calculation to determine a cost;
- applying an offset of the lattice mask template to the image and recalculating the cost;
- and
- repeating the applying and the recalculating steps to determine an alignment between the lattice mask template and the image.
An AFM for collecting data of a sample AFM comprising:
- a probe that interacts with a surface of the sample;
- a controller that controls the probe-sample interaction and collect atomic force microscopy (AFM) data of a sample having an array of periodic features;
- and
- wherein the controller:
- uses the AFM data to generate a sample image having feature pixels and background pixels;
- calculates a periodicity of the features;
- identifies peaks in the periodicity to determine a feature period and a lattice angle;
- constructs a lattice mask template using the feature period and the lattice angle;
- overlays the image with the lattice mask template;
- performs an alignment calculation to determine a cost;
- applying an offset of the lattice mask template to the image and recalculating the cost;
- and
- repeats the applying and the recalculating steps to determine an alignment between the lattice mask template and the image.
Dependencies are inferred from the claim text.