Spectroscopic scatterometer system
AssigneeKLA-Tencor Technologies Corporation
InventorsYiping Xu, Ibrahim Abdulhalim
Life of this patent
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Abstract
Before the diffraction from a diffracting structure on a semiconductor wafer is measured, where necessary, the film thickness and index of refraction of the films underneath the structure are first measured using spectroscopic reflectometry or spectroscopic ellipsometry. A rigorous model is then used to calculate intensity or ellipsometric signatures of the diffracting structure. The diffracting structure is then measured using a spectroscopic scatterometer using polarized and broadband radiation to obtain an intensity or ellipsometric signature of the diffracting structure. Such signature is then matched with the signatures in the database to determine the grating shape parameters of the structure.
Claims155
A method for measuring one or more parameters of a periodic diffracting structure adjacent to an associated structure, said associated structure having a thickness and an optical index, comprising:
- providing an optical index and a film thickness of the associated structure;
- constructing a reference database of one or more parameters related to said diffracting structure using said optical index and film thickness of the associated structure;
- directing a beam of electromagnetic radiation at a plurality of wavelengths at said periodic diffracting structure,
- detecting intensity data or ellipsometric parameters of a diffraction at said plurality of wavelengths from said diffracting structure of said beam;
- and
- comparing said detected intensity data or ellipsometric parameters to said database to determine said one or more parameters.
An apparatus for measuring one or more parameters of a periodic diffracting structure adjacent to at least one associated structure, said associated structure having a film thickness and an optical index, comprising:
- a computer constructing a reference database of one or more parameters related to said diffracting structure using said an optical index and a film thickness of the associated structure;
- optics directing a beam of electromagnetic radiation at a plurality of wavelengths at said periodic diffracting structure,
- a detector detecting intensity data or ellipsometric parameters of a diffraction at said plurality of wavelengths from said diffracting structure;
- and
- a processor comparing said detected intensity data or ellipsometric parameters to said database to determine said one or more parameters.
A method for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure, said method comprising:
- providing broadband radiation;
- polarizing the broadband radiation to produce a sampling beam;
- directing the sampling beam towards the structure at an oblique angle to the sample;
- detecting intensity data of radiation of the sampling beam that has been diffracted from the periodic diffracting structure over a range of wavelengths;
- and
- comparing the detected radiation intensity data to a reference database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the structure.
A method for measuring one or more parameters of a periodic diffracting structure adjacent to an associated structure of a sample, comprising:
- performing spectroscopic measurements on the associated structure to determine its characteristics;
- constructing a reference database of one or more parameters related to said diffracting structure using said characteristics of the associated structure;
- performing scatterometric measurements on the periodic diffracting structures to obtain intensity or ellipsometric data;
- and
- comparing said intensity or ellipsometric data to-the reference database to derive said one or more parameters.
An apparatus for measuring one or more parameters of a periodic diffracting structure adjacent to at least one associated structure, said associated structure having a film Thickness and an optical index, comprising:
- means for constructing a reference database of one or more parameters related to said diffracting structure using said an optical index and a film thickness of the associated structure;
- means for directing a beam of electromagnetic radiation at a plurality of wavelengths at said periodic diffracting structure;
- means for detecting intensity data of a diffraction at said plurality of wavelengths from said diffracting structure;
- and
- means for comparing said detected intensity data to said database to determine said one or more parameters.
An apparatus for measuring one or more parameters of a periodic diffracting structure adjacent to at least one associated structure, said associated structure having a film thickness and an optical index, comprising:
- means for constructing a reference database of one or more parameters related to said diffracting structure using said an optical index and a film thickness of the associated structure;
- means for directing a beam of electromagnetic radiation at a plurality of wavelengths at said periodic diffracting structure;
- means for detecting ellipsometric parameters of a diffraction at said plurality of wavelengths from said diffracting structure;
- and
- means for comparing said detected ellipsometric parameters to said database to determine said one or more parameters.
A method for measuring one or more parameters of a sample having a periodic diffracting structure and a film structure associated with the diffracting structure, comprising
- performing spectroscopic measurements on the sample to determine at least film thickness or index of refraction information of the associated structure;
- constructing a reference database of one or more parameters related to said diffracting structure using said film thickness or index of refraction information of the associated structure;
- and
- performing scatterometric measurements on the diffracting structure to obtain intensity or ellipsometric data.
A method for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure, said method comprising:
- providing a reference database;
- providing broadband radiation;
- polarizing the broadband radiation to produce a sampling beam;
- directing the sampling beam towards the periodic diffracting structure;
- detecting ellipsometric parameters of radiation of the sampling beam that has been diffracted from the structure over a range of wavelengths;
- and
- comparing the detected radiation to the reference database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the structure.
An apparatus for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure, said apparatus comprising.
- a reference database;
- optics providing a sampling beam of polarized broadband radiation and directing the beam towards the structure at an oblique angle to the sample;
- a detector detecting intensity data of radiation of the sampling beam that has been diffracted from the periodic diffracting structure over a range of wavelengths;
- and
- a processor comparing the detected radiation intensity data to a reference database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the structure.
An apparatus for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure, said apparatus comprising:
- a reference database;
- optics providing a sampling beam of polarized broadband radiation and directing the beam towards the structure at an oblique angle to the sample;
- a detector detecting ellipsometric parameters of radiation of the sampling beam that has been diffracted from the periodic diffracting structure over a range of wavelengths;
- and
- a processor comparing the detected ellipsometric parameters to a reference database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the structure.
Dependencies are inferred from the claim text.