Flexible mode scanning optical microscopy and inspection system

Patent metadata

Field	Value
Publication number	US-10422984-B2
Application number	US-201715615679-A
Country	US
Kind code	B2
Filing date	Jun 6, 2017
Priority date	May 12, 2017
Publication date	Sep 24, 2019
Grant date	Sep 24, 2019

Abstract

A method for flexible inspection of a sample includes forming an input beam using a beam source, blocking a portion of the input beam using an input mask, and forming a shaped beam from a portion of the input beam. The shaped beam is received at a first portion of an objective lens and focused onto a sample. A reflected beam is collected at a second portion of the objective lens. Scattered light is collected at the first and second portions of the objective lens and at a third portion of the objective lens. The scattered light is received at a dark-field detector module and a portion of the scattered light is directed to a dark-field detector. The dark-field detector module includes an output mask having one or more output apertures that allow at least part of the scattered light that passes through the third portion of the object lens to pass as the portion of the scattered light that is directed to the dark-field detector.

First claim

What is claimed is:

1. A system for bright-field and dark-field inspection of a sample, comprising:
a source configured to provide an input beam;
an input mask having an input aperture, the input mask configured to block a portion of the input beam and the input aperture arranged to allow a portion of the input beam to pass as a shaped beam;
an objective lens arranged to:
receive the shaped beam and focus the shaped beam onto a sample at a first oblique angle, the shaped beam passing through a first portion of the objective lens;
collect a reflected beam, the reflected beam being a portion of the shaped beam that is reflected from the sample at a second oblique angle, the reflected beam passing through a second portion of the objective lens; and
collect scattered light, the scattered light being a portion of the shaped beam that is scattered by the sample, the scattered light passing through the first and second portions of the objective lens and a third portion of the objective lens, wherein the first, second, and third portions of the objective lens comprise different portions of the objective lens;

a bright-field detector module configured to receive the reflected beam from the objective lens and direct the reflected beam to a bright-field detector; and
a dark-field detector module configured to receive the scattered light from the objective lens and direct a portion of the scattered light to a dark-field detector, the dark-field detector module including an output mask having one or more output apertures, the output mask configured to block the scattered light that passes through the first and second portions of the objective lens, and the one or more output apertures arranged to allow at least part of the scattered light that passes through the third portion of the object lens to pass as the portion of the scattered light that is directed to the dark-field detector.

2. The system of claim 1 wherein the first oblique angle is an oblique incidence angle.

3. The system of claim 1 wherein the first, second, and third portions of the objective lens are non-overlapping.

4. The system of claim 1 wherein the first, second, and third portions of the objective lens correspond to an entire numerical aperture of the objective lens.

5. The system of claim 1 wherein the first, second, and third portions of the objective lens correspond to less than an entire numerical aperture of the objective lens.

6. The system of claim 1 wherein the third portion of the objective lens includes a portion of the objective lens that is outside a plane of incidence of the shaped beam.

7. The system of claim 1 further comprising:
a beam expander for expanding the input beam;
a collimator for collimating the input beam;
a polarizer for polarizing the shaped beam; and
one or more beam splitters for separating at least a portion of the scattered light from the reflected beam.

8. A system for flexible inspection of a sample, comprising:
a source configured to provide an input beam;
an input mask having an input aperture, the input mask configured to block a portion of the input beam and the input aperture arranged to allow a portion of the input beam to pass as a shaped beam;
a beam splitter arranged to reflect the shaped beam;
an objective lens arranged to:
receive the shaped beam from the beam splitter and focus the shaped beam onto a sample, the shaped beam passing through a first portion of the objective lens;
collect a reflected beam, the reflected beam being a portion of the shaped beam that is reflected from the sample, the reflected beam passing through a second portion of the objective lens and being reflected by the beam splitter; and
collect scattered light, the scattered light being a portion of the shaped beam that is scattered by the sample, the scattered light passing through the first and second portions of the objective lens and through a third portion of the objective lens, wherein the first and second portions of the objective lens are different from the third portion of the objective lens, the scattered light passing through the first, second, and third portions of the objective lens and through the beam splitter;

a bright-field detector module configured to receive the reflected beam from the beam splitter and direct the reflected beam to a bright-field detector; and
a dark-field detector module configured to receive the scattered light passing through the beam splitter and direct a portion of the scattered light to a dark-field detector, the dark-field detector module including an output mask arranged downstream of the beam splitter and having one or more output apertures, the output mask configured to block the scattered light that passes through the first and second portions of the objective lens, and the one or more output apertures arranged to allow at least part of the scattered light that passes through the third portion of the object lens to pass as the portion of the scattered light that is directed to the dark-field detector.

9. The system of claim 8 wherein the first and second portions of the objective lens comprise substantially the same portions of the objective lens.

10. The system of claim 8 wherein the first and second portions of the objective lens comprise different portions of the objective lens.

11. The system of claim 8 wherein the shaped beam is focused onto the sample at a normal incidence.

12. The system of claim 8 wherein the output mask blocks the scattered light that passes through a center of the objective lens.

13. The system of claim 8 further comprising:
a beam expander for expanding the input beam;
a collimator for collimating the input beam;
a polarizer for polarizing the shaped beam; and
one or more beam splitters for separating at least a portion of the scattered light from the reflected beam.

14. A method for flexible inspection of a sample, the method comprising:
forming an input beam using a beam source;
blocking a portion of the input beam using an input mask;
forming a shaped beam from a portion of the input beam, the shaped beam being the portion of the input beam that passes through an aperture in the input mask;
receiving the shaped beam at an objective lens and focusing the shaped beam onto a sample, the shaped beam passing through a first portion of the objective lens;
collecting a reflected beam at the objective lens, the reflected beam being a portion of the shaped beam that is reflected from the sample, the reflected beam passing through a second portion of the objective lens;
receiving the reflected beam at a bright-field detector module and directing the reflected beam to a bright-field detector;
collecting scattered light at the objective lens, the scattered light being a portion of the shaped beam that is scattered by the sample, the scattered light passing through the first and second portions of the objective lens and through a third portion of the objective lens, wherein the first, second, and third portions of the objective lens comprise different portions of the objective lens; and
receiving the scattered light at a dark-field detector module and directing a portion of the scattered light to a dark-field detector, the dark-field detector module including an output mask having one or more output apertures, the output mask blocking the scattered light that passes through the first and second portions of the objective lens, and the one or more output apertures allowing at least part of the scattered light that passes through the third portion of the object lens to pass as the portion of the scattered light that is directed to the dark-field dete

Assignees

• Applied Materials Inc

Inventors

• Banna Samer
• Bishara Waheb
• Wu Dong
• Vaez-Iravani Mehdi

Classifications

• G02B21/004

  fixed arrays, e.g. switchable aperture arrays · CPC title

• G02B21/0056

  based on optical coherence, e.g. phase-contrast arrangements, interference arrangements · CPC title

• G02B5/0284

  used in reflection · CPC title

• G02B23/04

  for the purpose of beam splitting or combining, e.g. fitted with eyepieces for more than one observer (G02B23/10 takes precedence) · CPC title

• G02B21/125

  affording both dark- and bright-field illumination · CPC title