# US 12,111,270 B2 · Method of inspecting a wafer and apparatus for performing the same

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,111,270 B2
- Document ID: US12111270B2
- Status: Granted
- Kind: B2
- Application number: 17/725,917
- Filed: 2022-04-21
- Published: 2023-04-06
- Granted: 2024-10-08
- Earliest claimed: 2021-10-05
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Samsung Electronics Co., Ltd.
- Inventors: Juntaek Oh; Jinwoo Ahn; Kijoo Hong; Youngkyu Park; Eunsoo Hwang
- Web page: https://patentgrep.com/patent/US12111270B2

## CPC

- G01N 21/274: {Calibration, base line adjustment, drift correction}
- G01N 21/9501: {Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)}
- G01N 21/21: Polarisation-affecting properties (G01N21/19 takes precedence)
- G01N 21/31: Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry {(G01N21/72 takes precedence)}
- G01N 21/55: Specular reflectivity
- G01N 21/93: Detection standards; Calibrating {baseline adjustment, drift correction}
- G01N 2201/121: Correction signals
- G01N 2201/127: Calibration; base line adjustment; drift compensation
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A method of inspecting a wafer comprising measuring an intensity of an incident light and storing the measurement as stored incident light intensity, irradiating the incident light to the wafer, measuring an intensity of a reflected light from the wafer and storing the measurement as stored reflected light intensity, and correcting the stored reflected light intensity based on a difference between the stored incident light intensity and a reference intensity of a reference incident light.

## Claims

### Claim 1

A method of inspecting a wafer, the method comprising:
generating a reference incident light including a plurality of wavelengths;
measuring, by wavelength, an intensity of the reference incident light by the wavelengths and storing the measurement as stored reference incident light intensity;
irradiating the reference incident light to the wafer;
measuring, by wavelength, an intensity of a reference reflected light by the wavelengths and storing the measurement as stored reference reflected light intensity, the reference reflected light generated as a result of irradiating the reference incident light to the wafer;
generating an incident light including the plurality of wavelengths;
measuring, by wavelength, an intensity of the incident light and storing the measurement as stored incident light intensity;
irradiating the incident light to the wafer;
measuring, by wavelength, an intensity of a reflected light from the wafer and storing the measurement as stored reflected light intensity, the reflected light generated as a result of irradiating the incident light to the wafer;
determining a difference, at individual wavelengths, between the stored reflected light intensity and the stored reference reflected light intensity; and
correcting, by wavelength, the stored reflected light intensity based on the determined difference,
wherein there is a time lapse between when the stored reference reflected light intensity is measured and when the stored reflected light intensity is measured.

### Claim 2 (depends on 1)

The method of claim 1, wherein measuring the intensities of the incident light by the wavelengths comprises:
splitting the incident light;
dividing the split incident light by the wavelengths; and
measuring intensities of the divided incident light by the wavelengths.

### Claim 3 (depends on 2)

The method of claim 2, wherein measuring the intensities of the reflected light by the wavelengths comprises:
dividing the reflected light by the wavelengths; and
measuring intensities of the divided reflected light by the wavelengths.

### Claim 4 (depends on 1)

The method of claim 1, wherein measuring the intensities of the incident light by the wavelengths comprises:
dividing the incident light by the wavelengths;
splitting the divided incident light; and
measuring intensities of the split incident light by the wavelengths.

### Claim 5 (depends on 4)

The method of claim 4, wherein measuring the intensities of the reflected light by the wavelengths comprises:
irradiating the split incident light to the wafer; and
measuring intensities of the reflected light, from the wafer, by the wavelengths.

### Claim 6 (depends on 1)

The method of claim 1, wherein correcting the stored reflected light intensity comprises:
adding, by wavelength, the stored reflected light intensity to the difference between the stored reflected light intensity and the stored reference reflected light intensity.

### Claim 7 (depends on 6)

The method of claim 6, wherein obtaining the difference between the stored reflected light intensity and the stored reference reflected light intensity comprises:
obtaining a difference between the stored incident light intensity and the stored reference incident light intensity;
obtaining a ratio of the stored reflected light intensity with respect to the stored incident light intensity; and
multiplying the ratio by the difference between the stored incident light intensity and the stored reference incident light intensity.

### Claim 8 (depends on 1)

The method of claim 1, further comprising polarizing the incident light.

### Claim 9 (depends on 1)

The method of claim 1, further comprising analyzing the reflected light.

### Claim 10

A method of inspecting a wafer, the method comprising:
generating a reference incident light including a plurality of wavelengths;
measuring, by wavelength, an intensity of the reference incident light by the wavelengths and storing the measurement as stored reference incident light intensity;
irradiating the reference incident light to the wafer;
measuring, by wavelength, an intensity of a reference reflected light by the wavelengths and storing the measurement as stored reference reflected light intensity, the reference reflected light generated as a result of irradiating the reference incident light to the wafer;
generating an incident light including the plurality of wavelengths;
measuring, by wavelength, an intensity of the incident light and storing the measurement as stored incident light intensity;
polarizing the incident light;
irradiating the polarized incident light to the wafer;
measuring, by wavelength, an intensity of a reflected light from the wafer and storing the measurement as stored reflected light intensity, the reflected light generated as a result of irradiating the polarized incident light to the wafer;
determining a difference, at individual wavelengths, between the stored reflected light intensity and the stored reference reflected light intensity; and
correcting, by wavelength, the stored reflected light intensity based on the determined difference, at individual wavelengths,
wherein there is a time lapse between when the stored reference reflected light intensity is measured and when the stored reflected light intensity is measured.

### Claim 11 (depends on 10)

The method of claim 10, wherein measuring the intensities of the incident light by the wavelengths comprises:
splitting the incident light;
dividing the split incident light by the wavelengths; and
measuring intensities of the divided incident light by the wavelengths.

### Claim 12 (depends on 11)

The method of claim 11, wherein measuring the intensities of the reflected light by the wavelengths comprises:
dividing the reflected light by the wavelengths; and
measuring intensities of the divided reflected light by the wavelengths.

### Claim 13 (depends on 10)

The method of claim 10, wherein measuring the intensities of the incident light by the wavelengths comprises:
dividing the incident light by the wavelengths;
splitting the divided incident light; and
measuring intensities of the split incident light by the wavelengths.

### Claim 14 (depends on 13)

The method of claim 13, wherein measuring the intensities of the reflected light by the wavelengths comprises:
irradiating the split incident light to the wafer; and
measuring intensities of the reflected light, from the wafer, by the wavelengths.

### Claim 15 (depends on 10)

The method of claim 10, wherein correcting the stored reflected light intensity comprises:
adding, by wavelength, the stored reflected light intensity to the difference between the stored reflected light intensity and the stored reference reflected light intensity.

### Claim 16 (depends on 15)

The method of claim 15, wherein obtaining the difference between the stored reflected light intensity and the stored reference reflected light intensity comprises:
obtaining a difference between the stored incident light intensity and the stored reference incident light intensity;
obtaining a ratio of the stored reflected light intensity with respect to the stored incident light intensity; and
multiplying the ratio by the difference between the stored incident light intensity and the stored reference incident light intensity.

### Claim 17 (depends on 10)

The method of claim 10, further comprising analyzing the reflected light.