Multiple angles of incidence semiconductor metrology systems and methods

Patent metadata

Field	Value
Publication number	US-9310290-B2
Application number	US-201514745047-A
Country	US
Kind code	B2
Filing date	Jun 19, 2015
Priority date	Jan 14, 2013
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

An apparatus includes (i) a bright light source for providing an illumination beam at multiple wavelengths selectable with a range from a deep ultraviolet wavelength to an infrared wavelength, (ii) illumination optics for directing the illumination beam towards a sample at selectable sets of angles of incidence (AOI's) or azimuth angles (AZ's) and polarization states to provide spectroscopic ellipsometry, wherein the illumination optics include an apodizer for controlling a spot size of the illumination beam on the sample at each of the selectable AOI/AZ sets, (iii) collection optics for directing an output beam from the sample in response to the illumination beam at each of the selectable AOI/AZ sets and polarization states towards a detector that generates an output signal or image based on the output beam, and (v) a controller for characterizing a feature of the sample based on the output signal or image.

First claim

What is claimed is:

1. An ellipsometer apparatus for performing metrology of a semiconductor sample, comprising:
an illumination optics module for providing an illumination beam at a plurality of wavelengths that are selectable within a range from a vacuum ultraviolet (VUV) wavelength to an infrared (IR) wavelength and directing the illumination beam towards the sample at a plurality of angles of incidence (AOI's) and/or azimuth angles (AZ's), wherein the illumination optics comprises:
a first off axis parabolic (OAP) mirror,
a first translation mirror that is movable to receive the illumination beam at a plurality of positions to direct the illumination beam to a plurality of positions on the first OAP mirror so that the first OAP reflects the illumination beam to the sample at the discrete ranges of AOI and/or AZ one at a time, and
polarization generating optical elements for generating a plurality of polarization states for the illumination beam;

a collection optics module for collecting an output beam emanating from the sample at a plurality of discrete ranges of AOI and/or AZ and directing such output beam to a detector module, wherein the discrete ranges are collected one at a time and the output beam being in response to the illumination beam on the sample, wherein the collection optics module comprises:
a detector,
a second OAP,
a second translation mirror that is movable to receive the output beam at a plurality of positions to direct the output beam to a plurality of positions on the second OAP mirror so that the second OAP reflects the output beam at the discrete ranges of AOI and/or AZ to the detector one at a time, and
polarization analyzing optical elements for analyzing the polarization state of the output beam;

the detection module for receiving and detecting the output beam from the sample at the discrete ranges of AOI and/or AZ and the polarization states and generating a plurality of signals based on the output beam at the discrete ranges of AOI and/or AZ and the polarization states; and
one or more controllers that are each configured to control one or more of the following: selecting a wavelength range, selecting one or more of the discrete ranges of AOI and/or AZ for collection of the output beam, selecting the polarization states, and analyzing the signals at the discrete ranges of AOI and/or AZ and the polarization states to determine a characteristic of the sample,
wherein the illumination optics module and the collections optics modules comprises reflective optical elements between the polarization generation optical elements and the polarization analyzing optical elements.

2. An ellipsometer apparatus for performing metrology of a semiconductor sample, comprising:
an illumination optics module for providing an illumination beam at a plurality of wavelengths that are selectable within a range from a vacuum ultraviolet (VUV) wavelength to an infrared (IR) wavelength and directing the illumination beam towards the sample at a plurality of angles of incidence (AOI's) and/or azimuth angles (AZ's), wherein the illumination optics comprises:
a beam splitter;
an off axis parabolic (OAP) mirror,
a translation mirror that is movable to receive the illumination beam via the beam splitter at a plurality of translation positions of the translation mirror so as to direct the illumination beam to a plurality of corresponding positions on the OAP mirror so that the OAP reflects the illumination beam to the sample at the discrete ranges of AOI and/or AZ one at a time, and
polarization generating optical elements for generating a plurality of polarization states for the illumination beam;

a collection optics module for collecting an output beam emanating from the sample at a plurality of discrete ranges of AOI and/or AZ and directing such output beam to a detector module, wherein the discrete ranges are collected one at a time and the output beam being in response to the illumination beam on the sample, wherein the collection optics module comprises:
the beam splitter,
the OAP,
the translation mirror,
a spherical mirror for reflecting the output beam back towards the sample to cause a second output beam to emanate off the sample to reflect off the corresponding positions on the OAP and then reflect off the translation mirror at the plurality of translation positions towards the beam splitter and to the detector so as to collect the second output beam at the discrete ranges of AOI and/or AZ one at a time, and
polarization analyzing optical elements for analyzing the polarization state of the second output beam;

the detection module for receiving and detecting the second output beam from the sample at the discrete ranges of AOI and/or AZ and the polarization states and generating a plurality of signals based on the second output beam at the discrete ranges of AOI and/or AZ and the polarization states; and
one or more controllers that are each configured to control one or more of the following: selecting a wavelength range, selecting one or more of the discrete ranges of AOI and/or AZ for collection of the output beam, selecting the polarization states, and analyzing the signals at the discrete ranges of AOI and/or AZ and the polarization states to determine a characteristic of the sample,
wherein the illumination optics module and the collections optics modules comprises reflective optical elements between the polarization generation optical elements and the polarization analyzing optical elements.

3. An ellipsometer apparatus for performing metrology of a semiconductor sample, comprising:
an illumination optics module for providing an illumination beam at a plurality of wavelengths that are selectable within a range from a vacuum ultraviolet (VUV) wavelength to an infrared (IR) wavelength and directing the illumination beam towards the sample at a plurality of angles of incidence (AOI's) and/or azimuth angles (AZ's);
a collection optics module for collecting an output beam emanating from the sample at substantially all of the AOI's or AZ's and directing such output beam substantially simultaneously onto one or more detectors, the output beam being in response to the illumination beam on the sample,
wherein the illumination optics module includes polarization generating optical elements for generating a plurality of polarization states for the illumination beam, the collection optics module includes polarization analyzing optical elements for analyzing the polarization state of the output beam,
wherein the illumination optics module and collection optics module include reflective optical elements between the optical elements for generating the plurality of polarization states and the optical elements for analyzing the polarization states;
the one or more detectors for receiving and detecting the output beam from the sample at the AOI's and/or AZ's and the polarization states to generate a plurality of signals or images based on the output beam at such AOI's and AZ's and polarization states; and
one or more controllers that are each configured to control one or more of the following operations: selecting a wavelength range, selecting the polarization states, and analyzing the signals or images at the wavelengths, AOI's and/or AZ's, and the selected polarization states to determine a characteristic of the sample.

4. The apparatus of claim 3 , wherein the collection optics include one or more dispersing elements for dispersing the wavelengths at a wavelength plane and dispersing the AOI's and/or AZ's at an AOI/AZ plane whereby the wavelengths and the AOI's and/or AZ's are dispersed along two different detection directions.

5. The apparatus of claim 4 , wherein the two different directions are orthogonal to each other and the one or more dispersing elements have two different optic

Assignees

• Kla Tencor Corp

Inventors

• Wang David Y
• Flock Klaus
• Rotter Lawrence
• Krishnan Shankar
• De Veer Johannes D
• Filip Catalin
• Brady Gregory
• Arain Muzammil
• Shchegrov Andrei

Classifications

• G01N21/956

  Inspecting patterns on the surface of objects {(contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)} · CPC title

• G01N2201/06113

  Coherent sources; lasers · CPC title

• G01N21/9501

  Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20) · CPC title

• G01B2210/56

  Measuring geometric parameters of semiconductor structures, e.g. profile, critical dimensions or trench depth · CPC title

• G01N2021/214

  Variangle incidence arrangement · CPC title