US 2017/0205342 A1Published application

Systems And Methods For Extended Infrared Spectroscopic Ellipsometry

AssigneeKLA-Tencor Corporation

InventorsShankar Krishnan, David Y. Wang

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Abstract

Methods and systems for performing simultaneous spectroscopic measurements of semiconductor structures at ultraviolet, visible, and infrared wavelengths are presented herein. In another aspect, wavelength errors are reduced by orienting the direction of wavelength dispersion on the detector surface perpendicular to the projection of the plane of incidence onto the detector surface. In another aspect, a broad range of infrared wavelengths are detected by a detector that includes multiple photosensitive areas having different sensitivity characteristics. Collected light is linearly dispersed across the surface of the detector according to wavelength. Each different photosensitive area is arranged on the detector to sense a different range of incident wavelengths. In this manner, a broad range of infrared wavelengths are detected with high signal to noise ratio by a single detector. These features enable high throughput measurements of high aspect ratio structures with high throughput, precision, and accuracy.

Claims24

Dependent claims

A metrology system comprising:

one or more illumination sources configured to generate an amount of broadband illumination light;
an illumination optics subsystem configured to direct the amount of illumination light from the illumination source to a measurement spot on a surface of a specimen under measurement at one or more angles of incidence within a plane of incidence;
a collection optics subsystem configured to collect an amount of collected light from the measurement spot on the surface of the specimen;
a first detector having a planar, two-dimensional surface sensitive to incident light, wherein the first detector is configured to detect a response of the specimen to the amount of illumination light in a first range of wavelengths;
and
a second detector having a planar, two-dimensional surface sensitive to incident light, wherein the second detector is configured to detect a response of the specimen to the amount of illumination light in a second range of wavelengths at the same time the first detector detects the response of the specimen to the amount of illumination light in the first range of wavelengths by the first detector;
and
a first diffractive element configured to disperse a first portion of the amount of collected light in the first range of wavelengths toward the surface of the first detector;
and
a second diffractive element configured to disperse a second portion of the amount of collected light in the second range of wavelengths toward the surface of the second detector.

7 more elements

A metrology system comprising:

one or more illumination sources configured to generate an amount of broadband illumination light;
an illumination optics subsystem configured to direct the amount of illumination light from the illumination source to a measurement spot on a surface of a specimen under measurement at one or more angles of incidence within a plane of incidence;
a collection optics subsystem configured to collect an amount of collected light from the measurement spot on the surface of the specimen;
a first detector having a planar, two-dimensional surface sensitive to incident light, wherein the first detector is configured to detect a response of the specimen to the amount of illumination light in a first range of wavelengths, wherein the first detector includes two or more different surface areas each having different photosensitivity, wherein the two or more different surface areas are aligned with a direction of wavelength dispersion across the surface of the first detector;
and
a first diffractive element configured to disperse a first portion of the amount of collected light in the first range of wavelengths across the surface of the first detector.

3 more elements

A method comprising:

directing an amount of broadband illumination light from an illumination source to a measurement spot on a surface of a specimen under measurement at one or more angles of incidence within a plane of incidence;
collecting an amount of collected light from the measurement spot on the surface of the specimen;
directing a first portion of the amount of collected light in a first range of wavelengths toward a surface of a first detector and directing a second portion of the amount of collected light in a second range of wavelengths toward a surface of a second detector;
detecting a response of the specimen to the amount of illumination light in the first range of wavelengths;
and
detecting a response of the specimen to the amount of illumination light in the second range of wavelengths at the same time as the detecting of the response of the specimen to the amount of illumination light in the first range of wavelengths.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/336,705Filed 27 Oct 2016
Priority: 15 Jan 2016
Published: 20 Jul 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

G01N 21/3563
Using infrared light: for analysing solids; Preparation of samples therefor
G01J 3/0224
Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows: using polarising or depolarising elements
G01J 3/18
Generating the spectrum; Monochromators: using diffraction elements, e.g. grating
G01J 3/2803
Investigating the spectrum: using photoelectric array detector