Defect observation method, apparatus, and program

Patent metadata

Field	Value
Publication number	US-12564016-B2
Application number	US-202318152252-A
Country	US
Kind code	B2
Filing date	Jan 10, 2023
Priority date	Jan 27, 2022
Publication date	Feb 24, 2026
Grant date	Feb 24, 2026

Abstract

A defect observation method includes, as steps executed by a computer system, a first step of acquiring, as a bevel image, an image captured using defect candidate coordinates in a bevel portion as an imaging position by using a microscope or an imaging apparatus; and a second step of detecting a defect in the bevel image. The second step includes a step of determining whether there is at least one portion among a wafer edge, a wafer notch, and an orientation flat in the bevel image, a step of switching and selectively applying a defect detection scheme of detecting the defect from the bevel image from a plurality of schemes which are candidates based on a determination result, and a step of executing a process of detecting the defect from the bevel image in conformity with the switched scheme.

First claim

What is claimed is:

1 . A defect observation method of observing a defect in a bevel portion of a semiconductor wafer which is a sample using a computer system that includes a processor and a memory resource, the method comprising: as steps executed by the computer system,
a first step of acquiring, as a bevel image, an image in which defect candidate coordinates in the bevel portion are imaged as an imaging position using a microscope or an imaging apparatus; and a second step of detecting a defect in the bevel image, wherein the second step includes
a determination step of determining whether there is at least one portion among a wafer edge, a wafer notch, and an orientation flat in the bevel image,
a scheme switching step of switching and selectively applying a defect detection scheme of detecting the defect from the bevel image from a plurality of schemes which are candidates based on a determination result of the determination step, and
a defect detection step of executing a process of detecting the defect from the bevel image in conformity with the scheme switched in the scheme switching step.

2 . The defect observation method according to claim 1 ,
wherein the scheme switching step includes a reference image capturing scheme as one of the plurality of schemes, and wherein the reference image capturing scheme is a scheme of capturing a reference image corresponding to the bevel image and detecting the defect using the bevel image and the captured reference image.

3 . The defect observation method according to claim 2 , wherein the reference image capturing scheme is a scheme of selecting one or more imaging positions from imaging positions obtained through an operation for symmetry or rotation on an imaging position of the bevel image in the bevel portion and rotating or reversing an image captured at the selected imaging position and setting the reversed image as the reference image.

4 . The defect observation method according to claim 3 ,
wherein the microscope or the imaging apparatus includes a plurality of detectors disposed at different positions and detects images with different shades by the detectors, and wherein the reference image capturing scheme is a scheme of selecting an image closest to a shade of the bevel image among a plurality of images with different shades captured at the selected imaging position and setting the selected image as the reference image.

5 . The defect observation method according to claim 3 , wherein the reference image capturing scheme is a scheme of
dividing the bevel portion of the semiconductor wafer into a plurality of regions including at least first and second regions based on an imaging position indicated by the defect candidate coordinates, and selecting, in a plurality of bevel images at a plurality of imaging positions belonging to a region other than the first region, a plurality of imaging positions with respect to a plurality of reference images in accordance with the reference images corresponding to the bevel images so that the imaging positions are collected within the first region through the operation for the symmetry or rotation.

6 . The defect observation method according to claim 5 , wherein the reference image capturing scheme is a scheme of capturing the plurality of images at the plurality of selected imaging positions within the first region in order.

7 . The defect observation method according to claim 2 , wherein the scheme switching step is a step of switching the defect detection scheme to the reference image capturing scheme when there is the wafer edge and there are no wafer notch and no orientation flat as a determination result of the determination step.

8 . The defect observation method according to claim 1 ,
wherein the scheme switching step includes a reference image estimation scheme as one of the plurality of schemes, and wherein the reference image estimation scheme is a scheme of accepting the bevel image as an input, estimating an image with no defect as a reference image, and detecting the defect using the reference image estimated as the bevel image.

9 . The defect observation method according to claim 8 , wherein the reference image estimation scheme is a scheme of estimating the reference image by calculating a direction of a wafer edge in the bevel image and calculating an average image of the bevel images in the direction of the wafer edge.

10 . The defect observation method according to claim 8 , wherein the scheme switching step is a step of switching the defect detection scheme as the reference image estimation scheme when there is the wafer edge and there are no wafer notch and no orientation flat as a determination result of the determination step.

11 . The defect observation method according to claim 1 ,
wherein the scheme switching step includes a similar data comparison scheme as one of the plurality of schemes, and wherein the similar data comparison scheme is a scheme of, with regard to the bevel image of a target captured in a certain semiconductor wafer, searching for an image similar to the bevel image of the target based on another bevel image captured in another semiconductor wafer, setting the searched similar image as a reference image, and detecting the defect by comparing the bevel image of the target with the reference image.

12 . The defect observation method according to claim 11 , wherein the scheme switching step is a step of switching the defect detection scheme to the similar data comparison scheme when there is the wafer notch or there is the orientation flat as a determination result of the determination step.

13 . The defect observation method according to claim 1 ,
wherein the scheme switching step includes a statistical image comparison scheme as one of the plurality of schemes, and wherein the statistical image comparison scheme is a scheme of calculating a statistical value of luminance in an entire captured image, generating a consistent image in accordance with the statistical value, setting the consistent image as a reference image, and detecting the defect using the bevel image and the reference image.

14 . The defect observation method according to claim 1 , further comprising a step of displaying information regarding the determination result indicating whether there is the portion on a screen as a step executed by the computer system.

15 . A defect observation method of observing a defect in a bevel portion of a semiconductor wafer which is a sample using a computer system that includes a processor and a memory resource, the method comprising: as steps executed by the computer system,
a first step of acquiring, as a bevel image, an image in which the bevel portion is imaged using a microscope or an imaging apparatus; and a second step of detecting a defect in the bevel image, wherein the second step includes
a determination step of determining a region boundary in the bevel image,
a scheme switching step of switching and selectively applying a defect detection scheme of detecting the defect from the bevel image from a plurality of schemes which are candidates based on a determination result of the determination step, and
a defect detection step of executing a process of detecting the defect from the bevel image in conformity with the scheme switched in the scheme switching step.

16 . The defect observation method according to claim 15 ,
wherein the determination step is a step of executing classification based on whether there is the region boundary in the bevel image, and wherein the scheme switching step

Assignees

• Hitachi High Tech Corp

Inventors

• Kondo Naoaki
• Doi Yuki
• Miyamoto Atsushi
• Nakayama Hideki
• Kitsuki Hirohiko

Classifications

• G01N21/95607

  using a comparative method · CPC title

• G06T2207/10061

  from scanning electron microscope · CPC title

• G01N21/9503

  Wafer edge inspection · CPC title

• G06T2207/30148

  Semiconductor; IC; Wafer · CPC title

• H01J37/28

  with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} · CPC title