System and method for apodization in a semiconductor device inspection system

Patent metadata

Field	Value
Publication number	US-9645093-B2
Application number	US-201514930254-A
Country	US
Kind code	B2
Filing date	Nov 2, 2015
Priority date	Feb 10, 2012
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

An inspection system with selectable apodization includes a selectably configurable apodization device disposed along an optical pathway of an optical system. The apodization device includes one or more apodization elements operatively coupled to one or more actuation stages. The one or more actuation stages are configured to selectably actuate the one or more apodization elements along one or more directions. The inspection system includes a control system communicatively coupled to the one or more actuation stages. The control system is configured to selectably control an actuation state of at the one or more apodization elements so as to apply a selected apodization profile formed with the one or more apodization elements.

First claim

What is claimed:

1. An inspection system with selectable apodization, comprising:
an illumination source configured to illuminate a surface of a sample disposed on a sample stage;
a detector configured to detect at least a portion of light emanating from the surface of the sample, the illumination source and the detector being optically coupled via an optical pathway of an optical system including an illumination arm and a collection arm; and
a selectably configurable apodization device disposed along the optical pathway of the optical system, wherein the apodization device includes one or more apodization elements operatively coupled to one or more actuation stages, the one or more actuation stages configured to selectably actuate the one or more apodization elements along one or more directions in order to apply a selected apodization profile.

2. The inspection system of claim 1 , wherein the illumination source comprises:
at least one broad band illumination source.

3. The inspection system of claim 1 , wherein the illumination source comprises:
at least one narrow band illumination source.

4. The inspection system of claim 1 , wherein the inspection system is configured as a bright-field inspection system.

5. The inspection system of claim 1 , wherein the inspection system is configured as a dark-field inspection system.

6. The inspection system of claim 1 , wherein the one or more actuation stages of the selectably configurable apodization device comprises:
one or more translational stages.

7. The inspection system of claim 1 , wherein the one or more actuation stages of the selectably configurable apodization device comprises:
one or more rotational stages.

8. The inspection system of claim 1 , wherein the one or more actuation stages of the selectably configurable apodization device are configured to selectably actuate one or more apodization elements into the optical pathway of the optical system.

9. The inspection system of claim 1 , wherein the one or more apodization elements comprises:
two or more apodization elements.

10. The inspection system of claim 1 , wherein the one or more apodization elements comprises:
a single apodization element.

11. The inspection system of claim 1 , wherein the one or more apodization elements operatively coupled to on one or more actuation stages comprises:
a first apodization element disposed on a first actuation stage and at least a second apodization element disposed on at least a second actuation stage.

12. The inspection system of claim 1 , wherein the one or more apodization elements comprise:
one or more variable dot density apodizers.

13. The inspection system of claim 1 , wherein the one or more apodization elements include one or more neutral density coating apodizers.

14. The inspection system of claim 1 , wherein the one or more apodization elements include one or more serrated plates.

15. The inspection system of claim 1 , wherein the one or more apodization elements include one or more Fourier filters having one or more blocking elements, the one or more blocking elements including one or more apodized edges.

16. The inspection system of claim 1 , wherein the one or more apodization elements are configured to apply a first selected apodization profile along a first direction and at least a second selected apodization profile along a second direction.

17. The inspection system of claim 1 , wherein the selected apodization profile comprises:
at least one of a Gaussian profile, a cosine profile, or a Super Gaussian profile.

18. The inspection system of claim 1 , wherein the selected apodization profile is a function of one or more pattern features of the sample.

19. An inspection system suitable for providing apodization, comprising:
an illumination source configured to illuminate a surface of a sample disposed on a sample stage;
a detector configured to detect at least a portion of light emanating from the surface of the sample;
an optical system including an optical pathway configured to optically couple the illumination source and the detector; and
a serrated aperture assembly disposed along the optical pathway of the optical system and configured as an aperture of the optical system, the serrated aperture assembly including one or more serrated aperture stops, wherein at least some of the one or more serrated aperture stops include a plurality of serration features, the one or more serrated aperture stops including a serrated pattern having a selected orientation, wherein the one or more serrated aperture stops apply a selected apodization profile to illumination transmitted along the optical pathway of the optical system.

20. The inspection system of claim 19 , wherein the two or more serrated aperture stops include one or more sheet metal plates including a serrated aperture.

21. The inspection system of claim 19 , wherein the two or more serrated aperture stops include one or more patterned metallic material layers deposited on a transparent substrate forming a serrated aperture.

22. The inspection system of claim 19 , wherein the plurality of serration features of one or more of the serrated aperture stops are arranged with a selected pitch.

23. The inspection system of claim 22 , wherein the selected pitch of the plurality of serration features of one or more of the serrated aperture stops is a function of an aspect ratio of the detector.

24. The inspection system of claim 22 , wherein each of the plurality of serrations features has a selected size.

25. The inspection system of claim 19 , wherein the one or more serrated aperture stops comprise:
a first serrated aperture stop;
at least a second serrated aperture stop operatively coupled to the first serrated aperture stop, wherein the first serrated aperture stop is oriented with respect to the at least a second serrated aperture stop in order to achieve a selected pitch.

26. The inspection system of claim 19 , wherein the one or more serrated aperture stops comprise:
a first serrated aperture stop;
at least a second serrated aperture stop operatively coupled to the first serrated aperture stop, wherein the first serrated aperture stop is oriented with respect to the at least a second serrated aperture stop in order to achieve the apodization profile.

27. The inspection system of claim 19 , wherein the selected orientation of the serrated pattern produces diffraction orders substantially along a first direction.

28. The inspection system of claim 27 , wherein an axis of the detector is orientated along a second direction perpendicular to the first direction.

29. An inspection system suitable for providing apodization of illumination, comprising:
an illumination source configured to illuminate a surface of a sample disposed on a sample stage;
a detector configured to detect at least a portion of light emanating from the surface of the sample;
an optical system including an optical pathway configured to optically couple the illumination source and the detector;
a Fourier filter disposed along the optical pathway of the optical system, wherein the Fourier filter includes one or more illumination blocking elements arranged in an array pattern, wherein the one or more illumination blocking elements are arranged to block a portion of illumination from the sample, wherein one or more edge regio

Assignees

• Kla Tencor Corp

Inventors

• Sullivan Jamie M
• Janik Gary
• Cui Steve
• Runyon Rex
• Wilk Dieter
• Short Steve
• Haurylau Mikhail
• Zhang Qiang Q
• Chen Grace Hsiu-Ling
• Danen Robert M
• Martono Suwipin
• Verma Shobhit
• Cai Wenjian
• Brender Meier

Classifications

• G01N21/95623

  using a spatial filtering method (per se G02B) · CPC title

• G01N21/8806 Primary

  Specially adapted optical and illumination features · CPC title

• G01N21/9501 Primary

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

• G01N2021/8825

  Separate detection of dark field and bright field · CPC title

• G02B27/58

  Optics for apodization or superresolution; Optical synthetic aperture systems · CPC title