Patent US6204922B1 successfully refreshed from Google Patents.
US6204922B1
Expired / Lapsed
US
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Rapid and accurate thin film measurement of individual layers in a multi-layered or patterned sample
Assignee: Filmetrics Inc
•
Filing: 1998-12-11
•
Granted: 2001-03-20
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Expires: 2018-12-11
Abstract
Abstract Methods and apparatus for measuring the thickness of at least one individual film added to, removed from, or within a sample, characterized by the use of a shift in a selected peak of thickness spectral data to estimate the thickness of the individual film.
Inventors
- 👤 Scott A. Chalmers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:32
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/02; G01B11/06; G01B11/0616
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
303 words
A film measurement apparatus comprising: a white light source configured to generate a light signal; a first fiber optic cable connected to said light source to receive said light signal and further configured to direct said light signal onto a sample to obtain a reflected light signal having a plurality of wavelength components, each having an intensity; a second fiber optic cable positioned to receive said reflected light signal; a spectrometer configured to receive said reflected light signal from said second fiber optic cable, and derive therefrom a plurality of electrical signals, each representative of the intensity of a wavelength component of the reflected light; a computer programmed to receive from said spectrometer said plurality of electrical signals, and determine therefrom the thickness of at least one film added to or removed from said sample, the film comprising a material having a refractive index, by: obtaining data representative of the intensity of at least some of said wavelength components; arranging said data so that it is a function of a variable equal to the refractive index of the material divided by wavelength; determining the Power Spectral Density of the arranged data as a function of potential layer thickness; detecting at least one peak in the Power Spectral Density, including a selected peak; determining a shift in a selected peak upon, during, or after the addition of the layer to or the removal of the layer from the sample, the shift occurring in response to the addition or removal of the layer; and providing as an estimate of the thickness of the layer in at least one region sampled by the illumination light a value derived from the shift in the selected peak of the Power Spectral Density, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 2
Dependent Claim
303 words
A film measurement apparatus comprising: a white light source configured to generate a light signal; a first fiber optic cable connected to said light source to receive said light signal and further configured to direct said light signal onto a sample to obtain a reflected light signal having a plurality of wavelength components, each having an intensity; a second fiber optic cable positioned to receive said reflected light signal; a spectrometer configured to receive said reflected light signal from said second fiber optic cable, and derive therefrom a plurality of electrical signals, each representative of the intensity of a wavelength component of the reflected light; a computer programmed to receive from said spectrometer said plurality of electrical signals, and determine therefrom the thickness of at least one film added to or removed from said sample, the film comprising a material having a refractive index, by: obtaining data representative of the intensity of at least some of said wavelength components; arranging said data so that it is a function of a variable equal to the refractive index of the material divided by wavelength; determining the Power Spectral Density of the arranged data as a function of potential layer thickness; detecting at least one peak in the Power Spectral Density, including a selected peak; determining a shift in a selected peak upon, during, or after the addition of the layer to or the removal of the layer from the sample, the shift occurring in response to the addition or removal of the layer; and providing as an estimate of the thickness of the layer in at least one region sampled by the illumination light a value derived from the shift in the selected peak of the Power Spectral Density, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 3
Dependent Claim
288 words
A film measurement apparatus comprising: a light source configured to generate a light signal; a first optical director configured to receive said light signal and direct said light signal onto a sample to obtain a reflected light signal having a plurality of wavelength components, each having an intensity; a second optical director configured to direct said reflected light signal; an optical device configured to receive said reflected light signal from said second director, and derive therefrom a plurality of electrical signals, each representative of the intensity of a wavelength component of the reflected light; an electronic device part of or distinct from the optical device configured to receive said plurality of electrical signals and convert them to numeric representations of the intensity of each detected wavelength component; a computer programmed to receive said numeric representations, and determine therefrom the thickness of at least one film added to or removed from said sample by: obtaining data representative of the intensity of at least some of said wavelength components; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; detecting at least one peak in the thickness spectral data, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the layer to or removal of the layer from the sample, the shift occurring responsive to the addition or removal of the layer; and providing as an estimate of the thickness of the layer in at least one region sampled by the illumination light a value derived from the shift of the selected peak of the thickness spectral data, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 4
Dependent Claim
288 words
A film measurement apparatus comprising: a light source configured to generate a light signal; a first optical director configured to receive said light signal and direct said light signal onto a sample to obtain a reflected light signal having a plurality of wavelength components, each having an intensity; a second optical director configured to direct said reflected light signal; an optical device configured to receive said reflected light signal from said second director, and derive therefrom a plurality of electrical signals, each representative of the intensity of a wavelength component of the reflected light; an electronic device part of or distinct from the optical device configured to receive said plurality of electrical signals and convert them to numeric representations of the intensity of each detected wavelength component; a computer programmed to receive said numeric representations, and determine therefrom the thickness of at least one film added to or removed from said sample by: obtaining data representative of the intensity of at least some of said wavelength components; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; detecting at least one peak in the thickness spectral data, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the layer to or removal of the layer from the sample, the shift occurring responsive to the addition or removal of the layer; and providing as an estimate of the thickness of the layer in at least one region sampled by the illumination light a value derived from the shift of the selected peak of the thickness spectral data, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 5
Dependent Claim
20 words
The apparatus of claim 2 in which the computer is configured to derive the Fourier Transform of the intensity data.
Claim 6
Dependent Claim
21 words
The apparatus of claim 2 in which the computer is programmed to derive the Power Spectral Density of the intensity data.
Claim 7
Dependent Claim
157 words
A film measurement apparatus comprising: first means for directing a light signal onto a sample to obtain a reflected light signal having a plurality of wavelength components, each having an intensity; second means for receiving said reflected light signal and deriving therefrom data representative of the intensity of at least some of the wavelength components of the reflected light; third means for performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; and fourth means for detecting a shift in a selected peak of the thickness spectral data upon, during, or after the addition of a layer to or removal of the layer from the sample, the shift occurring responsive to the addition or removal of the layer, and directly estimating therefrom the thickness of the layer in at least one region thereof illuminated by the light without requiring details of any structure underlying or adjacent to the region.
Claim 8
Dependent Claim
157 words
A film measurement apparatus comprising: first means for directing a light signal onto a sample to obtain a reflected light signal having a plurality of wavelength components, each having an intensity; second means for receiving said reflected light signal and deriving therefrom data representative of the intensity of at least some of the wavelength components of the reflected light; third means for performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; and fourth means for detecting a shift in a selected peak of the thickness spectral data upon, during, or after the addition of a layer to or removal of the layer from the sample, the shift occurring responsive to the addition or removal of the layer, and directly estimating therefrom the thickness of the layer in at least one region thereof illuminated by the light without requiring details of any structure underlying or adjacent to the region.
Claim 9
Independent Claim
20 words
The apparatus of any of claims 1 , 2 , or 5 in which the sample is a patterned sample.
Claim 10
Independent Claim
20 words
The apparatus of any of claims 1 , 2 , or 5 in which the sample is a multi-layer sample.
Claim 11
Dependent Claim
276 words
A film measurement apparatus comprising: a light source configured to generate a light signal; a first optical director configured to receive said light signal and direct said light signal onto a sample to obtain a reflected light signal having a plurality of wavelength components, each having an intensity; a second optical director configured to direct said reflected light signal; an optical device configured to receive said reflected light signal from said second director, and derive therefrom a plurality of electrical signals, each representative of the intensity of a wavelength component of the reflected light; an electronic device part of or distinct from the optical device configured to receive said plurality of electrical signals and convert them to numeric representations of the intensity of each detected wavelength component; a transfer station having a window interfaced to a vacuum station for depositing new layers; and a computer programmed to receive said numeric representations, and determine therefrom the thickness of at least one film added to or removed from said sample by: obtaining data representative of the intensity of at least some of said wavelength components; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; detecting at least one peak in the thickness spectral data, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the layer to or removal of the layer from the sample; and providing as an estimate of the thickness of the layer in at least one region sampled by the illumination light a value derived from the shift of the selected peak of the thickness spectral data.
Claim 12
Dependent Claim
276 words
A film measurement apparatus comprising: a light source configured to generate a light signal; a first optical director configured to receive said light signal and direct said light signal onto a sample to obtain a reflected light signal having a plurality of wavelength components, each having an intensity; a second optical director configured to direct said reflected light signal; an optical device configured to receive said reflected light signal from said second director, and derive therefrom a plurality of electrical signals, each representative of the intensity of a wavelength component of the reflected light; an electronic device part of or distinct from the optical device configured to receive said plurality of electrical signals and convert them to numeric representations of the intensity of each detected wavelength component; a transfer station having a window interfaced to a vacuum station for depositing new layers; and a computer programmed to receive said numeric representations, and determine therefrom the thickness of at least one film added to or removed from said sample by: obtaining data representative of the intensity of at least some of said wavelength components; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; detecting at least one peak in the thickness spectral data, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the layer to or removal of the layer from the sample; and providing as an estimate of the thickness of the layer in at least one region sampled by the illumination light a value derived from the shift of the selected peak of the thickness spectral data.
Claim 13
Dependent Claim
216 words
A computer program medium embodying a program of instructions executable by computer to perform a method for measuring at least one film added to or removed from a sample from light reflected from the sample having a plurality of wavelength components, each having an intensity, and the film comprising a material having a refractive index, the method comprising the following steps: obtaining data representative of the intensity of at least some of said wavelength components; arranging said data so that it is a function of a variable equal to the refractive index of the material divided by wavelength; determining the Power Spectral Density of the arranged data as a function of potential layer thickness; detecting at least one peak in the Power Spectral Density, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the addition or removal of the layer; and providing as an estimated thickness of the film in at least one region sampled by the illumination light a value derived from the shift of the selected peak in the Power Spectral Density, the estimated thickness being derived without requiring details of any structure underlying or adjacent to the region.
Claim 14
Dependent Claim
216 words
A computer program medium embodying a program of instructions executable by computer to perform a method for measuring at least one film added to or removed from a sample from light reflected from the sample having a plurality of wavelength components, each having an intensity, and the film comprising a material having a refractive index, the method comprising the following steps: obtaining data representative of the intensity of at least some of said wavelength components; arranging said data so that it is a function of a variable equal to the refractive index of the material divided by wavelength; determining the Power Spectral Density of the arranged data as a function of potential layer thickness; detecting at least one peak in the Power Spectral Density, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the addition or removal of the layer; and providing as an estimated thickness of the film in at least one region sampled by the illumination light a value derived from the shift of the selected peak in the Power Spectral Density, the estimated thickness being derived without requiring details of any structure underlying or adjacent to the region.
Claim 15
Dependent Claim
178 words
A computer program medium embodying a program of instructions executable by a computer to perform a method for measuring at least one film added to or removed from a sample from light reflected from the sample having a plurality of wavelength components, each having an intensity, the method comprising the following steps: obtaining data representative of the intensity of at least some of said wavelength components; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; detecting a shift in a selected peak in the thickness spectral data upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the addition or removal of the layer; and providing as an estimate of the thickness of the film in at least one region sampled by the illumination light a value derived from the shift in the selected peak of the thickness spectral data, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 16
Dependent Claim
178 words
A computer program medium embodying a program of instructions executable by a computer to perform a method for measuring at least one film added to or removed from a sample from light reflected from the sample having a plurality of wavelength components, each having an intensity, the method comprising the following steps: obtaining data representative of the intensity of at least some of said wavelength components; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; detecting a shift in a selected peak in the thickness spectral data upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the addition or removal of the layer; and providing as an estimate of the thickness of the film in at least one region sampled by the illumination light a value derived from the shift in the selected peak of the thickness spectral data, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 17
Dependent Claim
177 words
A computer program medium embodying a program of instructions executable by a computer to perform a method for measuring at least one film added to or removed from a sample from light reflected from the film having a plurality of wavelength components, each having an intensity, the method comprising the following steps: obtaining data representative of the intensity of at least some of the wavelength components of the reflected light; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; and detecting at least one peak in the thickness spectral data, including a selected peak, and directly determining from a shift in the selected peak upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the addition or removal of the film, an estimate of the thickness of the film in at least one region sampled by the illumination light, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 18
Dependent Claim
177 words
A computer program medium embodying a program of instructions executable by a computer to perform a method for measuring at least one film added to or removed from a sample from light reflected from the film having a plurality of wavelength components, each having an intensity, the method comprising the following steps: obtaining data representative of the intensity of at least some of the wavelength components of the reflected light; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; and detecting at least one peak in the thickness spectral data, including a selected peak, and directly determining from a shift in the selected peak upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the addition or removal of the film, an estimate of the thickness of the film in at least one region sampled by the illumination light, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 19
Dependent Claim
22 words
The computer program medium of any of claims 9 , 10 , or 11 in which the sample is a patterned sample.
Claim 20
Dependent Claim
22 words
The computer program medium of any of claims 9 , 10 , or 11 in which the sample is a multi-layer sample.
Claim 21
Independent Claim
203 words
A method for measuring at least one film added to or removal from a sample from light reflected from the sample having a plurality of wavelength components, each having an intensity, and the film comprising a material having a refractive index, the method comprising the following steps: obtaining data representative of the intensity of at least some of said wavelength components; arranging said data so that it is a function of a variable equal to the refractive index of the material divided by wavelength; determining the Power Spectral Density of the arranged data as a function of potential layer thickness; detecting at least one peak in the Power Spectral Density, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the addition or removal of the film; and providing as an estimate of the thickness of the film in at least one region sampled by the illumination light a value derived from the shift in the selected peak of the Power Spectral Density, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 22
Independent Claim
203 words
A method for measuring at least one film added to or removal from a sample from light reflected from the sample having a plurality of wavelength components, each having an intensity, and the film comprising a material having a refractive index, the method comprising the following steps: obtaining data representative of the intensity of at least some of said wavelength components; arranging said data so that it is a function of a variable equal to the refractive index of the material divided by wavelength; determining the Power Spectral Density of the arranged data as a function of potential layer thickness; detecting at least one peak in the Power Spectral Density, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the addition or removal of the film; and providing as an estimate of the thickness of the film in at least one region sampled by the illumination light a value derived from the shift in the selected peak of the Power Spectral Density, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 23
Independent Claim
168 words
A method for measuring at least one film added to a sample from light reflected from the sample having a plurality of wavelength components, each having an intensity, the method comprising the following steps: obtaining data representative of the intensity of at least some of said wavelength components; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; detecting at least one peak in the thickness spectral data, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the additional or removal of the film; and providing as an estimate of the thickness of the film in at least one region sampled by the illumination light a value derived from the shift in the selected peak of the thickness spectral data, the estimate being derived requiring details of any structure underlying or adjacent to the region.
Claim 24
Independent Claim
168 words
A method for measuring at least one film added to a sample from light reflected from the sample having a plurality of wavelength components, each having an intensity, the method comprising the following steps: obtaining data representative of the intensity of at least some of said wavelength components; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; detecting at least one peak in the thickness spectral data, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the additional or removal of the film; and providing as an estimate of the thickness of the film in at least one region sampled by the illumination light a value derived from the shift in the selected peak of the thickness spectral data, the estimate being derived requiring details of any structure underlying or adjacent to the region.
Claim 25
Dependent Claim
19 words
The method of claim 15 in which the performing step includes deriving the Fourier Transform of the intensity data.
Claim 26
Dependent Claim
20 words
The method of claim 15 in which the performing step includes deriving the Power Spectral Density of the intensity data.
Claim 27
Dependent Claim
30 words
The method of claim 15 further comprising the step of adding the film to the sample or removing the film from the sample concurrently or simultaneously with the foregoing steps.
Claim 28
Independent Claim
169 words
A method for measuring at least one film added to a sample from light reflected from the sample having a plurality of wavelength components, each having an intensity, the method comprising the following steps: obtaining data representative of the intensity of at least some of said wavelength components; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; detecting at least one peak in the thickness spectral data, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the addition or removal of the film; and providing as an estimate of the thickness of the film in at least one region sampled by the illumination light a value derived from the shift in the selected peak of the thickness spectral data, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 29
Independent Claim
169 words
A method for measuring at least one film added to a sample from light reflected from the sample having a plurality of wavelength components, each having an intensity, the method comprising the following steps: obtaining data representative of the intensity of at least some of said wavelength components; performing analysis of said intensity data to obtain thickness spectral data as a function of potential layer thickness; detecting at least one peak in the thickness spectral data, including a selected peak; determining a shift in the selected peak upon, during, or after the addition of the film to or removal of the film from the sample, the shift occurring responsive to the addition or removal of the film; and providing as an estimate of the thickness of the film in at least one region sampled by the illumination light a value derived from the shift in the selected peak of the thickness spectral data, the estimate being derived without requiring details of any structure underlying or adjacent to the region.
Claim 30
Independent Claim
20 words
The method of any of claims 14 , 15 , or 19 in which the sample is a patterned sample.
Claim 31
Independent Claim
20 words
The method of any of claims 14 , 15 , or 19 in which the sample is a multi-layer sample.
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