US 9,311,431 B2Granted

Secondary target design for optical measurements

AssigneeKLA-Tencor Corporation

InventorsSungchul Yoo, Andrei V. Shchegrov, Thaddeus G. Dziura, InKyo Kim, SeungHwan Lee, ByeoungSu Hwang, Leonid Poslavsky

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Abstract

The disclosure is directed to improving optical metrology for a sample with complex structural attributes utilizing custom designed secondary targets. At least one parameter of a secondary target may be controlled to improve sensitivity for a selected parameter of a primary target and/or to reduce correlation of the selected parameter with other parameters of the primary target. Parameters for the primary and secondary target may be collected. The parameters may be incorporated into a scatterometry model. Simulations utilizing the scatterometry model may be conducted to determine a level of sensitivity or a level of correlation for the selected parameter of the primary target. The controlled parameter of the secondary target may be modified until a selected level of sensitivity or a selected level of correlation is achieved.

Claims32

Dependent claims

A system for analyzing at least one sample, comprising:

a sample stage configured to receive at least one sample;
at least one illumination source configured to illuminate at least one portion of the at least one sample;
at least one detector configured to receive illumination reflected from the at least one illuminated portion of the at least one sample;
and
a computing system communicatively coupled to the at least one detector, the computing system configured to:
receive a primary set of parameters of a primary target of the at least one sample from the at least one detector;
receive a secondary set of parameters of a secondary target of the at least one sample from the at least one detector, the secondary target including at least one parameter in common with the primary target, the secondary target further including at least one controlled parameter configured for at least one of:
increasing sensitivity for at least one selected parameter of the primary target;
or reducing correlation of at least one selected parameter of the primary target with at least one additional parameter of the primary target;
prepare a scatterometry model utilizing the primary set of parameters and the secondary set of parameters;
and
determine at least one parameter of the at least one sample utilizing the scatterometry model.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/665,436Filed 31 Oct 2012 · us provisional application
Priority: 3 Nov 2011
Published: US 2013/0116978 A19 May 2013
Granted: 12 Apr 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

G03F 7/70683
Metrology strategies: mark designs
G01N 21/47
Systems in which incident light is modified in accordance with the properties of the material investigated: scattering, i.e. diffuse reflection
G01N 21/956
Characterised by the material or shape of the object to be examined: inspecting patterns on the surface of objects
G03F 7/70625
Monitoring the printed patterns: dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness