Time-dependent defect inspection apparatus

Patent metadata

Field	Value
Publication number	US-2020075287-A1
Application number	US-201916552991-A
Country	US
Kind code	A1
Filing date	Aug 27, 2019
Priority date	Aug 28, 2018
Publication date	Mar 5, 2020
Grant date	—

Abstract

An improved charged particle beam inspection apparatus, and more particularly, a particle beam inspection apparatus for detecting a thin device structure defect is disclosed. An improved charged particle beam inspection apparatus may include a charged particle beam source to direct charged particles to a location of a wafer under inspection over a time sequence. The improved charged particle beam apparatus may further include a controller configured to sample multiple images of the area of the wafer at difference times over the time sequence. The multiple images may be compared to detect a voltage contrast difference or changes to identify a thin device structure defect.

First claim

What is claimed is:

1 . A charged particle beam system for inspecting a wafer, comprising:
a charged particle beam source including circuitry to direct charged particles to one or more areas of the wafer over one or more time sequences; and a controller including circuitry to:
produce a first set of images of a first area of the one or more areas during a first time sequence of the one or more time sequences; and
process the first set of images to detect a defect in a thin device structure in the wafer.

2 . The system of claim 1 , wherein the controller includes circuitry to:
sample a first image and a second image from the first set of images, wherein the first image is sampled at a first time of the first time sequence and the second image is sampled at a second time of the first time sequence; and compare the first image to the second image to identify the defect at the first area of the one or more areas of the wafer.

3 . The system of claim 1 , wherein the controller includes circuitry to:
produce a second set of images of the first area of the one or more areas during a second time sequence of the one or more time sequences; sample a first image from the first set of images and a second image from the second set of images; and compare the first image to the second image to identify the defect at the first area of the one or more areas of the wafer.

4 . The system of claim 1 , wherein the controller includes circuitry to:
produce a second set of images of a second area of the one or more areas during a second time sequence of the one or more time sequences, wherein the first area and the second area comprise same device structures; sample a first image from the first set of images and a second image from the second set of images; and compare the first image to the second image to identify the defect at the first area or the second area of the one or more areas of the wafer.

5 . The system of claim 3 , wherein the first image and the second image are sampled at corresponding times of the first time sequence and the second time sequence.

6 . The system of claim 2 , wherein the first image and the second image comprise voltage contrast levels.

7 . The system of claim 6 , wherein the controller includes circuitry to detect a difference between the voltage contrast levels of the first image and the voltage contrast levels of the second image to identify a defect in the thin device structure.

8 . The system of claim 1 , wherein the charged particle beam source includes circuitry to:
pre-scan the one or more areas of the wafer during a first part of the one or more time sequences; and inspect the one or more areas of the wafer during a second part of the one or more time sequences.

9 . The system of claim 8 , wherein the charged particle beam source includes circuitry to build up one or more surface potentials at the one or more areas of the wafer while performing the pre-scan during the first part of the one or more time sequences.

10 . The system of claim 9 , wherein the charged particle beam source performs the pre-scan until a device breakdown occur.

11 . The system of claim 1 , wherein the controller includes circuitry to adjust a time interval between the production of each image in the first set of images.

12 . The system of claim 2 , wherein the controller includes circuitry to adjust a time interval between the production of each image in the second set of images.

13 . The system of claim 1 , wherein the defect comprises an electrical defect associated with an electrical leakage in the thin device structure at the area.

14 . The system of claim 13 , wherein the thin device structure comprises a thin oxide that remains after an etching process.

15 . A non-transitory computer readable medium storing a set of instructions that is executable by a processor of a charged particle beam system to cause the charged particle beam system, with a charged particle beam source to direct charged particles onto one or more areas of the wafer over one or more time sequences, to perform a method comprising:
producing a first set of images of a first area of the one or more areas during a first time sequence of the one or more time sequences; and processing the first set of images to detect a defect in a thin device structure in the wafer.

Assignees

• Asml Netherlands Bv

Inventors

• Jen Chih-Yu
• Ma Long
• Wang Yongjun
• Jiang Jun

Classifications

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H01J37/263

  Contrast, resolution or power of penetration · CPC title

• H01J37/30

  Electron-beam or ion-beam tubes for localised treatment of objects · CPC title

• H01J2237/2817

  Pattern inspection · CPC title

• H01J2237/24564

  Measurements of electric or magnetic variables, e.g. voltage, current, frequency · CPC title