Phase shift measurement using transmittance spectra
Assigneen&k Technology, Inc.
InventorsGuoguang Li, Phillip Walsh, Shuqiang Chen, Abdul Rahim Forouhi
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Abstract
An apparatus and method for determining a physical parameter of features on a substrate by illuminating the substrate with an incident light covering an incident wavelength range Δλ, e.g., from 190 nm to 1000 nm, where the substrate is at least semi-transparent. A response light received from the substrate and the feature is measured to obtain a response spectrum of the response light. Further, a complex-valued response due to the feature and the substrate is computed and both the response spectrum and the complex-valued response are used in determining the physical parameter. A direct approximate phase measurement is provided when the response light is transmitted light.
Claims24
A method for determining a physical parameter of features on a substrate, said method comprising:
- a) illuminating said substrate with an incident light having an incident wavelength range Δλ within which said substrate is at least semi-transparent such that said incident light enters said substrate and said features;
- b) receiving a response light from said substrate and said features;
- c) measuring a response spectrum of said response light;
- d) computing a complex-valued response due to said features and said substrate;
- e) determining said physical parameter from said response spectrum and said complex-valued response;
- f) providing said determined physical parameter as an output;
- wherein said physical parameter is a relative transmission phase φ(λ) between a first part of said features and a second part of said features.
A method for determining a physical parameter of features on a substrate, said method comprising:
- a) illuminating said substrate with an incident light having an incident wavelength range Δλ within which said substrate is at least semi-transparent such that said incident light enters said substrate and said features;
- b) receiving a response light from said substrate and said features;
- c) measuring a response spectrum of said response light;
- d) computing a complex-valued response due to said features and said substrate;
- e) determining said physical parameter from said response spectrum and said complex-valued response;
- f) providing said determined physical parameter as an output;
- wherein said response light includes first light from a first part of said features, second light from a second part of said features, and third light from a third part of said features, and wherein a fraction a31 of said third part is similar to said first part and a fraction a32 of said third part is similar to said second part.
An apparatus for determining a physical parameter of features on a substrate, said apparatus comprising:
- a) an illumination source for producing an incident light having an incident wavelength range Δλ within which said substrate is at least semi-transparent;
- b) optics for guiding said incident light such that said incident light enters said substrate and said features;
- c) a detector for receiving a response light from said substrate and said features and measuring a measured response spectrum of said response light;
- d) a processing unit for computing a complex-valued response of said features and said substrate and for determining said physical parameter from said measured response spectrum and said complex-valued response;
- wherein said physical parameter is a relative transmission phase φ(λ) between a first part of said features and a second part of said features.
An apparatus for determining a physical parameter of features on a substrate, said apparatus comprising:
- a) an illumination source for producing an incident light having an incident wavelength range Δλ within which said substrate is at least semi-transparent;
- b) optics for guiding said incident light such that said incident light enters said substrate and said features;
- c) a detector for receiving a response light from said substrate and said features and measuring a measured response spectrum of said response light;
- d) a processing unit for computing a complex-valued response of said features and said substrate and for determining said physical parameter from said measured response spectrum and said complex-valued response;
- wherein said response light includes first light from a first part of said features, second light from a second part of said features, and third light from a third part of said features, and wherein a fraction a31 of said third part is similar to said first part and a fraction a32 of said third part is similar to said second part.
Dependencies are inferred from the claim text.