Method and system for providing a quality metric for improved process control

Patent metadata

Field	Value
Publication number	US-11372340-B2
Application number	US-201213508495-A
Country	US
Kind code	B2
Filing date	Apr 4, 2012
Priority date	Apr 6, 2011
Publication date	Jun 28, 2022
Grant date	Jun 28, 2022

Abstract

The present invention may include acquiring a plurality of overlay metrology measurement signals from a plurality of metrology targets distributed across one or more fields of a wafer of a lot of wafers, determining a plurality of overlay estimates for each of the plurality of overlay metrology measurement signals using a plurality of overlay algorithms, generating a plurality of overlay estimate distributions, and generating a first plurality of quality metrics utilizing the generated plurality of overlay estimate distributions, wherein each quality metric corresponds with one overlay estimate distribution of the generated plurality of overlay estimate distributions, each quality metric a function of a width of a corresponding generated overlay estimate distribution, each quality metric further being a function of asymmetry present in an overlay metrology measurement signal from an associated metrology target.

First claim

What is claimed:

1. A computer-implemented method for providing a quality metric suitable for improving process control in a semiconductor wafer fabrication process comprising:
acquiring a plurality of overlay metrology measurement signals from a plurality of metrology targets distributed across one or more fields of a wafer, each overlay metrology measurement signal corresponding with a metrology target of the plurality of metrology targets, the plurality of overlay metrology measurement signals acquired utilizing a first measurement recipe;
determining a plurality of overlay estimates for each of the plurality of overlay metrology measurement signals by applying a plurality of overlay algorithms to each overlay metrology measurement signal, wherein a first overlay estimate is determined with a first overlay algorithm of the plurality of overlay algorithms and an additional overlay estimate is determined with an additional overlay algorithm of the plurality of overlay algorithms for each of the plurality of the overlay metrology measurement signals;
generating a plurality of statistical overlay estimate distributions by generating a statistical overlay estimate distribution for each of the plurality of overlay metrology measurement signals from the plurality of metrology targets, wherein a first overlay estimate distribution is formed utilizing a first plurality of overlay estimates and an additional overlay estimate distribution is formed utilizing an additional plurality of overlay estimates; and
generating a first plurality of quality metrics based on a plurality of spans of the generated plurality of statistical overlay estimate distributions, wherein a first quality metric corresponds with one overlay estimate distribution generated for a first metrology target via the plurality of overlay algorithms, wherein the first quality metric is calculated based on a span of a corresponding overlay estimate distribution, wherein one or more of the quality metrics are proportional to an asymmetry-induced overlay inaccuracy in an overlay metrology signal.

2. The method of claim 1 , wherein acquiring a plurality of overlay metrology measurement signals from a plurality of metrology targets distributed across one or more fields of a wafer comprises:
performing an overlay metrology measurement on a plurality of metrology targets distributed across one or more fields of a wafer.

3. The method of claim 1 , further comprising:
performing a tool induced shift (TIS) correction to at least some of the acquired plurality of overlay metrology measurement signals.

4. The method of claim 1 , wherein each of the plurality of generated quality metrics is configured to identify an overlay deviation from a metrology target having substantially symmetric target structures.

5. The method of claim 1 , further comprising:
identifying one or more metrology targets of the plurality of metrology targets having a quality metric larger than a selected outlier level along at least one direction from a distribution of the plurality of quality metrics generated for the plurality of metrology targets;
determining a corrected plurality of metrology targets, wherein the corrected plurality of metrology targets excludes the identified one or more metrology targets having a quality metric deviating beyond a selected outlier level from the plurality of metrology targets; and
calculating a set of correctables utilizing the determined corrected plurality of metrology targets.

6. The method of claim 5 , further comprising:
transmitting the set of correctables to one or more process tools.

7. The method of claim 1 , further comprising:
acquiring at least an additional plurality of overlay metrology measurement signals from the plurality of metrology targets distributed across the one or more fields of the wafer, each overlay metrology measurement signal of the at least an additional plurality of overlay metrology measurement signals corresponding with a metrology target of the plurality of metrology targets, the at least an additional plurality of overlay metrology measurement signals acquired utilizing at least an additional measurement recipe;
determining at least an additional plurality of overlay estimates for each of the at least an additional plurality of overlay measurement signals by applying the plurality of overlay algorithms to each overlay measurement signal of the at least an additional plurality of measurement signals, wherein a first overlay estimate of the at least an additional plurality of overlay estimates is determined with a first overlay algorithm of the plurality of overlay algorithms and an additional overlay estimate of the at least an additional plurality of overlay estimates is determined with an additional overlay algorithm of the plurality of overlay algorithms;
generating at least an additional plurality of statistical overlay estimate distributions by generating a statistical overlay estimate distribution for each of the at least an additional plurality of overlay measurement signals from the plurality of metrology targets;
generating at least an additional plurality of quality metrics based on a plurality of spans of the generated at least an additional plurality of statistical overlay estimate distributions, wherein a first quality metric of the at least an additional plurality of quality metrics corresponds with one overlay estimate distribution of the generated at least an additional plurality of overlay estimate distributions; and
determining a process measurement recipe by comparing a distribution of the first plurality of quality metrics associated with the first measurement recipe to a distribution of the at least an additional plurality of quality metrics associated with the at least one additional measurement recipe.

8. The method of claim 7 , wherein the determining a process measurement recipe by comparing a distribution of the first plurality of quality metrics associated with the first measurement recipe to a distribution of the at least an additional plurality of quality metrics associated with the at least one additional measurement recipe comprises:
determining an optimum measurement recipe by comparing a distribution of the first plurality of quality metrics associated with the first measurement recipe to a distribution of the at least an additional plurality of quality metrics associated with the at least one additional measurement recipe, the optimum measurement recipe associated with a plurality of quality metrics of the first plurality of metrics and the at least an additional plurality of metrics having a substantially minimum distribution in at least one direction.

9. The method of claim 7 , wherein at least one of the first measurement recipe or the at least an additional measurement recipe comprise:
at least one of a wavelength of illumination, a filter configuration, a direction of illumination, a focus position, or polarization configuration.

10. A computer-implemented method for determining a quality metric suitable for improving process control in a semiconductor wafer fabrication process comprising:
acquiring a metrology measurement signal from a metrology target of a wafer;
determining a plurality of overlay estimates for the metrology target by applying a plurality of overlay algorithms to the acquired metrology measurement signal from the metrology target, wherein a first overlay estimate is determined for the metrology target with a first overlay algorithm of the plurality of overlay algorithms and an additional overlay estimate is determined for the metrology target with an additional overlay algorithm of the plurality of overlay algorithms, wherein the first overlay algorithm is dif

Assignees

• Kandel Daniel
• Cohen Guy
• Klein Dana
• Levinski Vladimir
• Sapiens Noam
• Shulman Alex
• Kamenetsky Vladimir
• Amit Eran
• Vakshtein Irina
• Kla Corp

Inventors

• Kandel Daniel
• Cohen Guy
• Klein Dana
• Levinski Vladimir
• Sapiens Noam
• Shulman Alex
• Kamenetsky Vladimir
• Amit Eran
• Vakshtein Irina

Classifications

• G03F7/705

  Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions · CPC title

• G03F7/706843

  Metrology apparatus · CPC title

• G03F7/706839

  Modelling, e.g. modelling scattering or solving inverse problems · CPC title

• G03F7/70633 Primary

  Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching · CPC title

• G01N2223/6116

  semiconductor wafer · CPC title