# US 2023/0058064 A1 · Film thickness measuring device and film thickness measuring method

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- Number: US 2023/0058064 A1
- Document ID: US20230058064A1
- Status: Published application
- Kind: A1
- Application number: 17/797,193
- Filed: 2021-02-09
- Published: 2023-02-23
- Earliest claimed: 2020-02-13
- Assignees: Hamamatsu Photonics K.K.
- Applicants: Hamamatsu Photonics K.K.
- Inventors: Tomonori NAKAMURA; Kenichi OHTSUKA; Satoshi ARANO; Kunihiko TSUCHIYA
- Web page: https://patentgrep.com/patent/US20230058064A1

## CPC

- G01B 11/06: for measuring thickness {; e.g. of sheet material (thickness measurement by thermal means G01B21/085)}
- G01N 21/8422: {Investigating thin films, e.g. matrix isolation method}
- G01B 11/0608: {Height gauges}
- G01B 11/0625: {with measurement of absorption or reflection}
- G01B 11/0633: {using one or more discrete wavelengths}
- G01B 11/0691: {of objects while moving (G01B11/0616 takes precedence)}
- G01B 15/02: for measuring thickness
- G01J 3/027: {Control of working procedures of a spectrometer; Failure detection; Bandwidth calculation}
- G01J 3/36: Investigating two or more bands of a spectrum by separate detectors
- G01J 9/00: Measuring optical phase difference (devices or arrangements for controlling the phase of light beams G02F1/01); Determining degree of coherence; Measuring optical wavelength (spectrometry G01J3/00)
- G02B 27/141: {using dichroic mirrors}
- G01N 21/9501: {Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)}
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- 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)
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A film thickness measuring apparatus includes a light irradiation unit configured to irradiate an object with light in a planar shape, an optical element having a transmittance and a reflectance changing according to wavelengths in a predetermined wavelength range, the optical element being configured to separate light from the object by transmitting and reflecting the light, an imaging unit configured to photograph light separated by the optical element, and an analysis unit configured to estimate a film thickness of the object based on a signal from the imaging unit photographing light, in which the light irradiation unit emits light having a wavelength included in the predetermined wavelength range of the optical element.

## Claims

### Claim 1

A film thickness measuring apparatus comprising:
a light irradiator configured to irradiate an object with light in a planar shape;
an optical element having a transmittance and a reflectance changing according to wavelengths in a predetermined wavelength range, the optical element being configured to separate light from the object by transmitting and reflecting the light;
an imager configured to photograph light separated by the optical element; and
an analyzer configured to estimate a film thickness of the object based on a signal from the imager photographing light,
wherein the light irradiator emits light having a wavelength comprised in the predetermined wavelength range of the optical element.

### Claim 2 (depends on 1)

The film thickness measuring apparatus according to claim 1, wherein the analyzer estimates a film thickness corresponding to each pixel based on wavelength information of each pixel in the imager.

### Claim 3 (depends on 1)

The film thickness measuring apparatus according to claim 1, wherein the analyzer estimates a film thickness by further considering an angle of light with which the object is irradiated.

### Claim 4 (depends on 1)

The film thickness measuring apparatus according to claim 1, wherein the light irradiator irradiates the object with diffused light.

### Claim 5 (depends on 4)

The film thickness measuring apparatus according to claim 4, wherein the light irradiator has a light guide plate configured to generate the diffused light.

### Claim 6 (depends on 1)

The film thickness measuring apparatus according to claim 1, further comprising a bandpass filter disposed between the optical element and the imager.

### Claim 7

A film thickness measuring method comprising:
irradiating an object with light in a planar shape;
photographing light separated by an optical element, the optical element having a transmittance and a reflectance changing according to wavelengths in a predetermined wavelength range and being configured to separate light from the object by transmitting and reflecting the light; and
deriving a wavelength based on a photographing result and estimating a film thickness of the object based on the wavelength.