US 10,705,434 B2 · Verification metrology target and their design

Abstract

Metrology target design methods and verification targets are provided. Methods include using OCD data related to designed metrology target(s) as an estimation of a discrepancy between a target model and a corresponding actual target on a wafer, and adjusting a metrology target design model to compensate for the estimated discrepancy. The dedicated verification targets may include overlay target features and be size optimized to be measurable by an OCD sensor, to enable compensation for inaccuracies resulting from production process variation. Methods also include modifications to workflows between manufacturers and metrology vendors which provide enabled higher fidelity metrology target design models and ultimately higher accuracy of metrology measurements.

Claims16

Dependent claims

A metrology target design method comprising:

designing, based on one or more target coordinates, at least one designed overlay metrology target model;
designing at least one verification target as a cell comprising overlay target features and having a cell side dimension of at least 10 μm;
receiving optical critical dimension (OCD) data:
related to the at least one designed overlay metrology target model from an OCD sensor;
and,
at least partially derived from measuring the at least one verification target with the OCD sensor;
using the OCD data as an estimation of a discrepancy between the at least one designed overlay metrology target model and a corresponding actual target on a wafer;
and,
adjusting the at least one designed overlay metrology target model to compensate for the discrepancy.

6 more elements

Dependencies are inferred from the claim text.

Verification metrology target and their design

Life of this patent

Verification metrology target and their design

Life of this patent

Abstract

Claims16