Method for determining types of defects in monocrystalline silicon wafer

Patent metadata

Field	Value
Publication number	US-12474277-B2
Application number	US-202318528402-A
Country	US
Kind code	B2
Filing date	Dec 4, 2023
Priority date	Dec 5, 2022
Publication date	Nov 18, 2025
Grant date	Nov 18, 2025

Abstract

The present invention provides a method for determining the type of defects in a monocrystalline silicon wafer, which includes the steps of: using LST to measure particles in an as-grown silicon wafer and thereby obtaining a first measurement, and determining a V-rich region based on the first measurement and a first preset density value; and subjecting the silicon wafer to a thermal treatment, again using LST to measure particles in the silicon wafer and thereby obtaining a second measurement, and determining a Pv region, an I-rich region and a Pi region based on the second measurement, a second preset density value and a third preset density value. As a result, a particle density can be utilized as a basis for accurately and efficiently determining a region of interest of a monocrystalline silicon wafer as one of a V-rich region, a Pv region, a Pi region and an I-rich region.

First claim

What is claimed is:

1 . A method for determining the type of defects in a monocrystalline silicon wafer, comprising steps of:
measuring particles in an as-grown silicon wafer by using laser scattering tomography to obtain a first measurement, and determining a V-rich region based on the first measurement and a first preset density value; and subjecting the silicon wafer to a thermal treatment, measuring particles in the silicon wafer by using laser scattering tomography again to obtain a second measurement, and determining a Pv region, an I-rich region and a Pi region based on the second measurement, a second preset density value and a third preset density value.

2 . The method of claim 1 , wherein the first measurement comprises a particle density, and wherein determining the V-rich region based on the first measurement and the first preset density value comprises:
determining a region, for which the particle density of the first measurement is higher than the first preset density value, as the V-rich region.

3 . The method of claim 1 , wherein the silicon wafer has an oxygen content of 5 ppma to 20 ppma, and the thermal treatment that the silicon wafer is subjected to is performed in an argon atmosphere at a temperature of 800° C. to 1000° C. for 2 hours to 4 hours.

4 . The method of claim 1 , wherein the second measurement comprises a particle density, and wherein determining the Pv region, the I-rich region and the Pi region based on the second measurement, the second preset density value and the third preset density value comprises:
determining a region, for which the particle density of the second measurement is higher than the second preset density value, as the Pv region; determining a region, for which the particle density of the second measurement lies between the second and third preset density values, as the I-rich region; and determining a region, for which the particle density of the second measurement is lower than the third preset density value, as the Pi region.

5 . The method of claim 1 , wherein the first preset density value is in a range of 2×10 6 cm −3 to 10 7 cm −3 , the second preset density value is in a range of 4×10 6 cm −3 to 4×10 7 cm −3 , and the third preset density value is in a range of 5×10 5 cm −3 to 3×10 6 cm −3 .

6 . A method for determining the type of defects in a monocrystalline silicon wafer, comprising steps of:
measuring particles in an as-grown silicon wafer by using laser scattering tomography to obtain a third measurement, and determining a V-rich region based on a first preset size, a fourth preset density value and the third measurement; and subjecting the silicon wafer to a thermal treatment, measuring particles in the silicon wafer by using laser scattering tomography again to obtain a fourth measurement, and determining a Pv region, an I-rich region and a Pi region based on the fourth measurement, a second preset size, a fifth preset density value and a sixth preset density value.

7 . The method of claim 6 , wherein the third measurement comprises a particle density and a particle size, and wherein determining the V-rich region based on the first preset size, the fourth preset density value and the third measurement comprises:
determining a region, for which the particle density of the third measurement is higher than the fourth preset density value and the particle size of the third measurement is greater than the first preset size, as the V-rich region.

8 . The method of claim 6 , wherein the silicon wafer has an oxygen content of 5 ppma to 20 ppma, and the thermal treatment that the silicon wafer is subjected to is performed in an argon atmosphere at a temperature of 800° C. to 1000° C. for 2 hours to 4 hours.

9 . The method of claim 6 , wherein the fourth measurement comprises a particle density and a particle size, and wherein determining the Pv region, the I-rich region and the Pi region based on the fourth measurement, the second preset size, the fifth preset density value and the sixth preset density value comprises:
determining a region, for which the particle density of the fourth measurement is higher than the fifth preset density value, as the Pv region; determining a region, for which the particle density of the fourth measurement lies between the fifth and sixth preset density values and the particle size of the fourth measurement is greater than the second preset size, as the I-rich region; and determining a region, for which the particle density of the fourth measurement is lower than the sixth preset density value and the particle size of the fourth measurement is greater than the second preset size, as the Pi region.

10 . The method of claim 6 , wherein the first preset size ranges from 20 nm to 25 nm, the second preset size ranges from 30 nm to 40 nm, the fourth preset density value ranges from 5×10 5 cm −3 to 5×10 6 cm −3 , the fifth preset density value ranges from 4×10 7 cm −3 to 10 8 cm −3 , and the sixth preset density value ranges from 0 to 4×10 6 cm −3 .

Assignees

• Zing Semiconductor Corp

Inventors

• Wei Xing
• Wang Hao
• Li Minghao
• Yu Yuehui

Classifications

• G01N21/49

  within a body or fluid · CPC title

• G01N21/9501

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

• G01N21/9505 Primary

  Wafer internal defects, e.g. microcracks · CPC title