Bright and dark field scatterometry systems for line roughness metrology
AssigneeKLA-Tencor Corporation
InventorsGuorong Vera Zhuang, Steven R. Spielman, Leonid Poslavsky, Daniel C. Wack, John Fielden
Life of this patent
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Abstract
Line edge roughness or line width roughness of a feature on a sample may be determined from incident radiation scattered from the feature. An amount of ordered scattered radiation characterized by a discrete diffraction order is determined and a diffuse scattered radiation signal is measured. A ratio between an intensity of the ordered scattered incident radiation and an intensity of the diffuse scattered radiation signal is determined. The line edge roughness or line width roughness is determined from the ratio.
Claims25
A method for determining line edge roughness or line width roughness of a feature on a sample, comprising:
- a) directing incident radiation onto the feature;
- b) determining an amount of ordered scattered radiation leaving the feature characterized by a discrete diffraction order;
- c) measuring an amount of diffuse scattered radiation signal leaving the feature;
- d) determining a ratio between an intensity of the ordered scattered radiation and an intensity of the diffuse scattered radiation signal;
- and
- e) determining the line edge roughness or line width roughness from the ratio.
An apparatus for determining line edge roughness or line width roughness of a feature on a sample, comprising:
- a) an illumination system, having optics configured to direct radiation onto the feature of the sample;
- b) an ordered scattering module configured to determine an amount of ordered scattered radiation leaving the feature that is characterized by a discrete diffraction order;
- c) a diffuse scattering module configured to measure an amount of diffuse scattered radiation signal leaving the feature;
- d) a ratio module configured to determine a ratio between an intensity of the ordered scattered radiation characterized by a discrete diffraction order and an intensity of diffuse scattered radiation signal;
- and
- e) an edge roughness module configured to determine the line edge roughness or line width roughness of the feature on the sample using information from the ratio module.
Dependencies are inferred from the claim text.