Method and Apparatus for Detecting Substrate Surface Variations

Patent metadata

Field	Value
Publication number	US-2020124977-A1
Application number	US-201816624609-A
Country	US
Kind code	A1
Filing date	May 17, 2018
Priority date	Jun 21, 2017
Publication date	Apr 23, 2020
Grant date	—

Abstract

Disclosed is a method and associated inspection apparatus for detecting variations on a surface of a substrate. The method comprises providing patterned inspection radiation to a surface of a substrate. The inspection radiation is patterned such that an amplitude of a corresponding enhanced field is modulated in a manner corresponding to the patterned inspection radiation. The scattered radiation resultant from interaction between the enhanced field and the substrate surface is received and variations on the surface of the substrate are detected based on the interaction between the enhanced field and the substrate surface. Also disclosed is a method of detecting any changes to at least one characteristic of received radiation, the said changes being induced by the generation of a surface plasmon at said surface of the optical element.

First claim

1 - 15 . (canceled)

16 . A method comprising:
providing inspection radiation to a surface of a substrate wherein the inspection radiation is patterned such that an amplitude of a corresponding enhanced field is modulated in a manner corresponding to the patterned inspection radiation; receiving scattered radiation resultant from an interaction between the enhanced field and the substrate surface; and detecting variations on the surface of the substrate based on the interaction between the enhanced field and the substrate surface.

17 . The method of claim 16 , wherein the enhanced field is an evanescent field.

18 . The method of claim 17 , further comprising:
providing the inspection radiation to the surface of the substrate via an optical element and at an angle configured to create the evanescent field; and positioning a surface of the optical element within a distance smaller than a wavelength of the patterned inspection radiation to the surface of the substrate.

19 . The method of claim 18 , wherein the optical element is a solid immersion lens.

20 . The method of claim 18 , wherein the surface of the optical element is positioned at a first distance from the substrate such that the evanescent field is generated by total internal reflection of the patterned radiation at the surface of the optical element in the absence of any significant variation on the surface of the substrate in an area of the substrate being inspected.

21 . The method of claim 18 , further comprising:
receiving radiation reflected by the optical element; and detecting any changes to at least one characteristic of the received radiation, the changes being induced by the generation of a surface plasmon at the surface of the optical element.

22 . The method of claim 21 , comprising:
detecting a change in an incident angle of the inspection radiation on the substrate at which a surface plasmon is generated from a characteristic of the received radiation; and determining the presence of a variation on the surface of the substrate based on a detection of a change in an incident angle, and wherein, the detecting the change in the incident angle of the inspection radiation on the substrate at which a surface plasmon is generated from the characteristic of the received radiation comprises determining a change in position of a drop in detected intensity of the received radiation indicative of the optical element not reflecting the inspection radiation.

23 . The method of claim 18 , wherein the surface of the optical element comprises an enhancing dielectric and/or metal deposition.

24 . The method of claim 18 , wherein the optical element comprises a plurality of such optical elements arranged in an array.

25 . The method of claim 24 , wherein:
the patterned inspection radiation is obtained by providing separate beams of the inspection radiation to respective surfaces of a subset of the plurality of optical elements, the subset corresponding to a desired pattern, or the patterned inspection radiation is obtained by providing the inspection radiation to respective surfaces of the plurality of optical elements arranged in an array, the plurality of optical elements being operable to pattern the inspection radiation.

26 . The method of claim 18 , wherein:
the patterned inspection radiation is obtained by providing the inspection radiation to the surface of the optical element, and the optical element has a first pattern thereon operable to pattern the inspection radiation.

27 . The method of claim 18 , wherein the providing comprises:
providing an input inspection radiation; and patterning the input inspection radiation by using a patterning component comprising a first pattern to obtain the patterned inspection radiation, wherein the first pattern is focused on the surface of the optical element.

28 . The method of claim 16 , wherein the providing comprises:
providing an input inspection radiation; patterning the input inspection radiation by using a patterning component comprising a first pattern to obtain the patterned inspection radiation; focusing the patterned inspection radiation on the substrate; and using a detection arrangement to capture the scattered radiation over a range of scattering angles.

29 . The method of claim 16 , further comprising a near-field scanning optical microscopy method, wherein:
the providing inspection radiation comprises using an array of optical microscopy detectors, each optical microscopy detector providing the illumination radiation; and the receiving scattered radiation comprises using the array of optical microscopy detectors to receive the scattered radiation from within a distance, relative to the surface of the substrate, smaller than a wavelength of the inspection radiation, thereby creating the enhanced field.

30 . An inspection apparatus comprising:
an illumination system operable to provide an inspection radiation; patterning means configured to pattern the inspection radiation such that an amplitude of a corresponding enhanced field is modulated in a manner corresponding to the patterned inspection radiation; and a detector operable to detect scattered radiation caused by an interaction between the patterned enhanced field and the substrate surface.

Assignees

• Asml Netherlands Bv

Inventors

• D'Achard Van Enschut Johannes Franciscus Martinus
• Druzhinina Tamara
• Kumar Nitisb
• Roy Sarathi
• Huang Yang-Shan
• Den Boef Arie Jeffrey
• Nienhuys Han-Kwang
• Van Zwol Pieter-Jan
• Roc-Sol Sander Bas

Classifications

• G01N21/47

  Scattering, i.e. diffuse reflection (G01N21/25, G01N21/41 take precedence {G01N21/55 takes precedence}) · CPC title

• G01N21/9501

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

• G01B11/30

  for measuring roughness or irregularity of surfaces · CPC title

• G01N21/8806

  Specially adapted optical and illumination features · CPC title

• G01N2021/8829

  Shadow projection or structured background, e.g. for deflectometry · CPC title