US 2026/0251553 A1Published application

Multi-Function Optical Analyzer

AssigneeBoard of Trustees of Michigan State University

InventorQi Hua FAN

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Abstract

A multi-function optical analyzer and method are configured to measure optical properties of materials. In another aspect of the present apparatus and method, a single instrument synergistically measures a refractive index, an extinction coefficient, a thickness, an optical reflectance, and an optical transmittance of a thin film. An aspect of the present optical analyzer apparatus and method transmit light along multiple offset-angled paths to a sample, and reflect the light along multiple offset-angled paths from the specimen to a spectrometer detector. Still another aspect of the present apparatus and method primarily measure a reflectance spectra of an s-wave at oblique angles and non-polarized light at a normal incident angle. This combines the functions of two instruments—an ellipsometer and a spectrophotometer.

Claims21

Dependent claims

An optical analyzer for characterizing a film on a substrate, the optical analyzer comprising:

(a) a light source configured to emit light along:
(i) a first transmitting path including at least a first transmitting fiber optic cable and a first lens, a distal end of the first transmitting fiber optic cable having a first axial transmitting direction pointed toward the film;
(ii) a second transmitting path including at least a second transmitting fiber optic cable, a second lens and a transmitting polarizer, the transmitting polarizer being configured to filter out p-wave and transmit s-wave to the second lens and the film, and a distal end of the second transmitting fiber optic cable having a second axial transmitting direction pointed toward the film;
(iii) the first axial transmitting direction being offset angled from the second axial transmitting direction;
(b) at least one spectrometer configured to receive the light reflected from the film along:
(i) a first receiving path including at least a first receiving fiber optic cable, a distal end of the first receiving fiber optic cable having a first axial receiving direction pointed away from the film;
(ii) a second receiving path including at least a second receiving fiber optic cable, a third lens and a receiving polarizer, the receiving polarizer being configured to filter out p-wave and transmit s-wave to the second lens and the at least one spectrometer, and a distal end of the second receiving fiber optic cable having a second axial receiving direction pointed away from the film;
and
(iii) the first axial receiving direction being offset angled from the second axial receiving direction.

6 more elements

An optical analyzer for characterizing a film on a substrate, the optical analyzer comprising:

(a) a light source configured to emit light along:
(i) a first transmitting path including at least a first transmitting fiber optic cable and a first lens, a distal end of the first transmitting fiber optic cable having a first axial transmitting direction pointed toward the film;
(ii) a second transmitting path including at least a second transmitting fiber optic cable, and a distal end of the second transmitting fiber optic cable having a second axial transmitting direction pointed toward the film;
(iii) the first axial transmitting direction being offset angled from the second axial transmitting direction;
(b) at least one spectrometer configured to receive the light reflected from the film along:
(i) a first receiving path including at least a first receiving fiber optic cable, a distal end of the first receiving fiber optic cable having a first axial receiving direction pointed away from the film;
(ii) a second receiving path including at least a second receiving fiber optic cable, and a distal end of the second receiving fiber optic cable having a second axial receiving direction pointed away from the film;
(iii) the first axial receiving direction being offset angled from the second axial receiving direction;
(c) a programmable controller connected to the at least one spectrometer, the spectrometer and the programmable controller being configured to measure a reflectance spectra of polarized light at multiple different angles to directly determine the following with regard to the film:
(i) a refractive index;
(ii) an extinction coefficient;
(iii) a thickness;
(iv) an optical reflectance;
and
(v) an optical transmittance.

12 more elements

An optical analyzer for characterizing a film on a substrate, the optical analyzer comprising:

(a) a light source;
(b) a first transmitting path including a first transmitting lens, the first transmitting path having a first axial transmitting direction pointed toward the film;
(c) a second transmitting path including a second transmitting lens and a transmitting polarizer, the transmitting polarizer being configured to filter out p-wave and transmit s-wave to the second transmitting lens and the film, and the second transmitting path having a second axial transmitting direction pointed toward the film;
(d) the first axial transmitting direction being offset angled from the second axial transmitting direction, both of which are offset angled from a plane of an exposed surface of the film and both of which are offset angled from a nominal direction that is perpendicular to the plane through the exposed surface of the film;
(e) a first receiving path including a first receiving lens, a distal end of the first receiving path having a first axial receiving direction pointed away from the film;
(f) a second receiving path including a second receiving lens and a receiving polarizer, the receiving polarizer being configured to filter out p-wave and transmit s-wave to the second receiving lens, and a distal end of the second receiving path having a second axial receiving direction pointed away from the film;
and
(g) the first axial receiving direction being offset angled from the second axial receiving direction, both of which are offset angled from the plane of the exposed surface of the film and both of which are offset angled from the nominal direction that is perpendicular to the plane through the exposed surface of the film;
(h) a combined transmitting and receiving path including a lens, a distal end of the combined transmitting and receiving path having an axial direction that is coaxially aligned with the normal direction that is perpendicular to the plane through the exposed surface of the film;
(i) the first and the second receiving paths providing reflected light from the film along oblique sets of angles, that is received by at least one spectrometer to provide multiple and different oblique reflection measurements;
(j) the combined transmitting and receiving path providing reflected light from the film along the normal angle, that is received by the at least one spectrometer to provide a normal reflection measurement;
and
(k) a programmable controller configured to use output from the at least one spectrometer to determine a refractive index, an extinction coefficient, film thickness directly from at least the three reflectance measurements and film transmittance.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 19/548,067Filed 24 Feb 2026
Priority: 25 Feb 2025
Published: 27 Aug 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

G01N 21/211
Polarisation-affecting properties: ellipsometry
G01B 11/0625
Of coating: with measurement of absorption or reflection
G01B 11/0641
Of coating: with measurement of polarization
G01N 21/21
Systems in which incident light is modified in accordance with the properties of the material investigated: polarisation-affecting properties

Family

Application63/762,888Us provisional application · filed 25 Feb 2025
US 2026/0251553 A1This patent

From the US filing history. Foreign family members aren’t listed.

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