KR20210093765A - Optical measurement apparatus and optical measurement method - Google Patents

Abstract

The present invention is to measure transmittance or reflectance of a measurement object more accurately. An optical measuring device of the present invention comprises: an irradiation optical system for irradiating irradiation light including a plurality of wavelengths to a measurement object; a light-receiving optical system for receiving measurement light that is transmitted light or reflected light generated from the measurement object by irradiation of the irradiated light on the measurement object; and a polarizing plate, wherein the polarizing plate can be located in either one of the said irradiation optical system and the said light-receiving optical system.

Description

Optical measuring device and optical measuring method

The present invention relates to an optical measuring device and an optical measuring method.

In recent years, there has been known a technique for measuring the film thickness of a measurement object, for example, by measuring the transmittance or reflectance of the measurement object based on transmitted light or reflected light generated from the measurement object by irradiation of light to the measurement object.

For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2015-59750) discloses the following film thickness measurement method. That is, the film thickness measurement method includes the steps of irradiating continuous light to the object to be measured, obtaining a spectral spectrum of the reflected or transmitted light, and obtaining a power spectrum from the spectral spectrum by Fourier transform; With respect to the splitting peak, a step of determining the film thickness of the object to be measured is provided based on the midpoint of the first characteristic point for the peak on the shortest wavelength side and the second characteristic point for the peak on the longest wavelength side.

Moreover, the following film thickness measuring apparatus is disclosed by patent document 2 (Unexamined-Japanese-Patent No. 2009-198361). That is, the film thickness measuring apparatus includes a measuring unit that measures a spectral spectrum by spectroscopy of reflected light or transmitted light obtained by irradiating a white light to an object to be measured, and performs a predetermined operation on the spectral spectrum measured by the measuring unit, A film thickness measuring apparatus comprising a calculating unit for measuring a film thickness of a measurement target, wherein the calculating unit converts a spectral spectrum in a preset wavelength band among the spectral spectrum into a wavenumber spectral spectrum rearranged at a predetermined wavenumber interval a first transforming unit, a second converting unit converting the wavenumber spectral spectrum converted by the first converting unit into a power spectrum, and the position of the center of gravity of a peak appearing in the power spectrum converted by the second converting unit and a calculation unit which calculates the thickness of the measurement target based on the position of the center of gravity.

Moreover, the following retardation measuring apparatus is disclosed by patent document 3 (Unexamined-Japanese-Patent No. 2011-133428). That is, the retardation measuring device is a retardation measuring device that irradiates polarized light to an object to be measured, and measures the retardation of the portion to be measured using the light returned from the object to be measured, and irradiates the object to be measured. a light source for outputting white light, a polarizing plate into which the light returned from the measurement object is incident while polarizing the output light of the light source, and the light returning from the measurement object and passing through the polarizing plate is incident , a spectrometer that generates a spectral spectrum of the light, and an arithmetic section that receives the spectral spectrum generated by the spectral section and calculates and outputs retardation from the spectral spectrum.

Moreover, the following film thickness measuring method is disclosed by patent document 4 (Unexamined-Japanese-Patent No. 2012-112760). That is, the film thickness measurement method is a film thickness measurement method for measuring the film thickness of a measurement object having birefringence, irradiating polarized light to the measurement object, and spectroscopy the light transmitted through the measurement object It comprises a process of generating a spectrum and measuring retardation from this spectral spectrum, and calculating the film thickness of this to-be-measured object from the difference in the refractive index of the said measured retardation and to-be-measured object.

Japanese Laid-Open Patent Publication No. 2015-59750 Japanese Patent Laid-Open No. 2009-198361 Japanese Patent Laid-Open No. 2011-133428 Japanese Patent Laid-Open No. 2012-112760

For example, Patent Document 1 discloses that two peaks corresponding to two different optical film thicknesses of the measurement object appear in the power spectrum of the spectral spectrum of reflected light or transmitted light of the measurement object. In the technique described in patent document 1 and patent document 2, based on such a power spectrum, the film thickness of a measurement object may not be able to be determined accurately.

A technique capable of measuring the transmittance or reflectance of an object to be measured more accurately is preferable beyond the technique described in Patent Documents 1 to 4 as described above.

The present invention has been made in order to solve the above-described problems, and an object thereof is to provide an optical measuring device and an optical measuring method capable of more accurately measuring the transmittance or reflectance of a measurement object.

(1) In order to solve the above problems, an optical measuring device according to an aspect of the present invention includes an irradiation optical system for irradiating a measurement object with irradiation light including a plurality of wavelengths, and by irradiating the irradiation light to the measurement object. A light-receiving optical system for receiving measurement light, which is transmitted light or reflected light generated from the measurement object, and a polarizing plate, the polarizing plate is configured to be positioned in either one of the irradiation optical system and the light-receiving optical system.

In this way, a polarizing plate configured to be positioned in either one of the irradiation optical system and the light receiving optical system is provided, and the irradiated light transmitted through the polarizing plate is irradiated to the measurement object, or the measurement light transmitted through the polarizing plate is received. , for example, in the case of measuring the transmittance spectrum or reflectance spectrum of a measurement object having birefringence, the transmittance spectrum or reflectance spectrum with a reduced beat component can be measured, and a polarizing plate in both the irradiation optical system and the light receiving optical system Compared with the structure in which , it is possible to suppress a decrease in the light-receiving intensity of the measurement light in the light-receiving optical system. Accordingly, it is possible to more accurately measure the transmittance or reflectance of the measurement object.

(2) Preferably, the said polarizing plate is fixedly formed only in either one of the said irradiation optical system and the said light-receiving optical system.

With such a configuration, when measuring the transmittance or reflectance of the measurement object, an operation such as moving the position of the polarizing plate is unnecessary, so the measurement of the transmittance or reflectance of the measurement object can be started with a simple configuration and simple operation. can

(3) Preferably, the optical measurement device further includes an adjustment unit capable of adjusting the direction of the absorption axis of the polarizing plate as a direction on a plane intersecting the optical path of the irradiation light or the optical path of the measurement light.

With such a configuration, the direction of the absorption axis of the polarizing plate with respect to the optical axis of the measurement object having birefringence can be adjusted, and the beat component in the generated transmittance spectrum or reflectance spectrum can be further reduced.

(4) In order to solve the above problems, an optical measurement method according to an aspect of the present invention is an optical measurement method using an optical measurement device including an irradiation optical system and a light receiving optical system, and using the irradiation optical system, multiple wavelengths A step of irradiating an irradiated light comprising: a step of irradiating the measurement object with the light-receiving optical system, and the step of receiving measurement light that is transmitted or reflected light generated from the measurement object by irradiation of the irradiated light on the measurement object And, in the step of irradiating the irradiated light to the measurement object or the step of receiving the measurement light, the irradiated light transmitted through a polarizing plate is irradiated to the measurement object, or the measurement light transmitted through the polarizing plate is received .

In this way, in the case of measuring the transmittance spectrum or reflectance spectrum of the measurement object having birefringence by irradiating the irradiated light transmitted through the polarizing plate to the measurement object or by receiving the measurement light transmitted through the polarizing plate, for example. In this case, the transmittance spectrum or the reflectance spectrum with a reduced beat component can be measured, and compared with the configuration in which polarizing plates are formed in both the irradiation optical system and the light receiving optical system, a decrease in the light reception intensity of the measurement light in the light receiving optical system is suppressed can do. Accordingly, it is possible to more accurately measure the transmittance or reflectance of the measurement object.

(5) Preferably, the said polarizing plate is fixedly formed only in either one of the said irradiation optical system and the said light-receiving optical system.

With such a configuration, when measuring the transmittance or reflectance of the measurement object, an operation such as moving the position of the polarizing plate is unnecessary, so the measurement of the transmittance or reflectance of the measurement object can be started with a simple configuration and simple operation. can

(6) Preferably, in the optical measurement method, each of the measurement lights is received when the direction of the absorption axis of the polarizing plate is different as a direction on a plane intersecting with the optical path of the irradiation light or the measurement light. and calculating the film thickness of the measurement target based on the result.

With such a configuration, for example, when measuring the film thickness of a measurement object having birefringence, the light reception result of measurement light when the polarizing plate is arranged so that the direction of the absorption axis is parallel to the slow axis of the measurement object , the film thickness of the measurement object can be more accurately calculated using the light reception result of the measurement light when the polarizing plate is disposed so that the direction of the absorption axis is parallel to the fast axis of the measurement object.

ADVANTAGE OF THE INVENTION According to this invention, the transmittance|permeability or reflectance of a measurement object can be measured more accurately.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the structure of the optical measuring apparatus which concerns on 1st Embodiment of this invention.
Fig. 2 is a diagram showing an example of the configuration of the optical measuring apparatus according to the first embodiment of the present invention.
Fig. 3 is a diagram showing the configuration of a light-receiving optical system in the optical measuring apparatus according to the first embodiment of the present invention.
4 is a diagram showing the configuration of a processing device in the optical measuring device according to the first embodiment of the present invention.
Fig. 5 is a diagram showing a transmittance spectrum generated by the optical measuring apparatus according to Comparative Example 1 of the first embodiment of the present invention.
6 is a diagram showing a power spectrum of a transmittance spectrum generated by the optical measuring device according to Comparative Example 1 of the first embodiment of the present invention.
Fig. 7 is a diagram showing a transmittance spectrum generated by the optical measuring apparatus according to Comparative Example 2 of the first embodiment of the present invention.
Fig. 8 is a diagram showing the power spectrum of the transmittance spectrum generated by the optical measuring device according to Comparative Example 2 of the first embodiment of the present invention.
9 is a diagram showing a transmittance spectrum generated by the optical measuring device according to the first embodiment of the present invention.
Fig. 10 is a diagram showing a power spectrum of a transmittance spectrum generated by the optical measuring device according to the first embodiment of the present invention.
11 is a diagram showing a transmittance spectrum generated by the optical measuring device according to Comparative Example 3 of the first embodiment of the present invention.
12 is a diagram showing a power spectrum of a transmittance spectrum generated by the optical measuring device according to Comparative Example 3 of the first embodiment of the present invention.
Fig. 13 is a diagram showing a transmittance spectrum generated by the optical measuring apparatus according to Comparative Example 4 of the first embodiment of the present invention.
Fig. 14 is a diagram showing the power spectrum of the transmittance spectrum generated by the optical measuring device according to Comparative Example 4 of the first embodiment of the present invention.
15 is a diagram showing a transmittance spectrum generated by the optical measuring device according to the first embodiment of the present invention.
16 is a diagram showing a power spectrum of a transmittance spectrum generated by the optical measuring device according to the first embodiment of the present invention.
It is a figure which shows the relationship between the direction of the absorption axis of a polarizing plate in the optical measuring apparatus which concerns on 1st Embodiment of this invention, and the direction of the slow axis of a measurement object.
Fig. 18 is a diagram showing an example of the configuration of an optical measuring device according to Modification Example 2 of the first embodiment of the present invention.
19 is a flowchart illustrating an example of an operation procedure for calculating the film thickness of a measurement object in the optical measurement apparatus according to the first embodiment of the present invention.
20 is a flowchart illustrating an example of the operation procedure when adjusting the direction of the absorption axis of the polarizing plate in the optical measuring device according to the first embodiment of the present invention.
Fig. 21 is a diagram showing an example of the configuration of the optical measuring device according to the second embodiment of the present invention.
22 is a diagram showing an example of the configuration of an optical measuring device according to a second embodiment of the present invention.
Fig. 23 is a diagram showing an example of the configuration of an optical measuring apparatus according to Modification Example 1 of the second embodiment of the present invention.
Fig. 24 is a diagram showing an example of the configuration of an irradiation optical system in an optical measuring apparatus according to a modification of the second embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described using drawing. In addition, the same code|symbol is attached|subjected to the same or corresponding part in a figure, and the description is not repeated. Moreover, you may combine arbitrarily at least one part of embodiment described below.

<First embodiment>

[Optical measuring device]

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the structure of the optical measuring apparatus which concerns on 1st Embodiment of this invention.

Referring to FIG. 1 , the optical measuring device 101 includes an irradiation optical system 10 , a light receiving optical system 20 , a processing device 30 , an adjustment unit 51 , a base member 4 , and a support member. (6) and a polarizing plate 50 are provided. The base member 4 and the supporting member 6 fix the light receiving optical system 20 . In addition, the optical measuring apparatus 101 is not limited to the structure provided with the base member 4 and the support member 6, Instead of the base member 4 and the support member 6, or the base member 4 and another member for fixing the light-receiving optical system 20 in addition to the supporting member 6 may be provided.

The polarizing plate 50 is comprised so that it may be located in either one of the irradiation optical system 10 and the light receiving optical system 20 . For example, the polarizing plate 50 is fixedly formed only in either one of the irradiation optical system 10 and the light receiving optical system 20 . In the example shown in FIG. 1, the polarizing plate 50 is fixedly formed only in the light receiving optical system 20. As shown in FIG.

Fig. 2 is a diagram showing an example of the configuration of the optical measuring device according to the first embodiment of the present invention. 2 : has shown the state in which the measurement object S which is a measurement object of the optical measurement apparatus 101 is arrange|positioned.

With reference to FIG. 2 , the optical measuring device 101 measures the transmittance of a measurement target S such as a film passing through the target region R .

For example, the optical measurement apparatus 101 automatically measures the transmittance|permeability spectrum in the some measurement position M on the measurement object S conveyed through the target area|region R in the manufacturing line of the measurement object S. That is, the optical measurement apparatus 101 measures the transmittance|permeability spectrum in the some measurement position M on the measurement object S in-line.

In more detail, the optical measurement apparatus 101 calculates the transmittance|permeability for every wavelength in the measurement position M of the measurement object S conveyed, for example by performing transmittance|permeability measurement periodically.

[Irradiation optical system]

The irradiation optical system 10 irradiates the measurement object S with irradiation light including a plurality of wavelengths in a straight line. In more detail, the irradiation optical system 10 irradiates irradiation light to the target area|region R which is a linear area|region through which the measurement object S passes.

The irradiation optical system 10 includes a light source 11 and a line light guide 12 .

The light source 11 emits light including a plurality of wavelengths. The spectrum of the light emitted from the light source 11 may be a continuous spectrum or a line spectrum. The wavelength of the light emitted from the light source 11 is set according to the range of wavelength information to be acquired from the measurement object S, or the like. The light source 11 is, for example, a halogen lamp.

The line light guide 12 receives the light emitted from the light source 11 and radiates the received light from the line-shaped opening, thereby irradiating the target region R with the irradiation light in a straight line. A diffusion member for suppressing light quantity non-uniformity, for example, is disposed on the emission surface of the irradiated light in the line light guide 12 . The line light guide 12 is arrange|positioned just below the surface on which the measurement object S is conveyed.

For example, when performing inline measurement of the transmittance spectrum of the measurement object S, the irradiation optical system 10 irradiates the target area R with irradiation light at the measurement timing, while irradiating the target area R with the timing other than the measurement timing. Stop irradiating the irradiated light. The irradiation optical system 10 may be configured to continuously irradiate the target region R with irradiation light irrespective of the measurement timing.

[Light-receiving optical system]

The light-receiving optical system 20 receives the measurement light which is transmitted light generated from the measurement object S by irradiation of the irradiation light with respect to the measurement object S.

The light receiving optical system 20 includes a polarizing plate 50 , an objective lens 21 , an imaging spectrometer 22 , and an imaging unit 23 .

The light receiving optical system 20 is disposed at a position opposite to the line light guide 12 with the measurement object S interposed therebetween.

The light-receiving optical system 20 receives, as measurement light, the transmitted light that has passed through the target region R among the irradiated light emitted from the line light guide 12 . Specifically, the light-receiving optical system 20 receives the transmitted light of the measurement object S passing through the target region R among the irradiated light emitted from the line light guide 12 .

Fig. 3 is a diagram showing the configuration of a light-receiving optical system in the optical measuring apparatus according to the first embodiment of the present invention.

Referring to FIG. 3 , the imaging spectrometer 22 has a slit portion 221 , a first lens 222 , a diffraction grating 223 , and a second lens 224 . The slit portion 221 , the first lens 222 , the diffraction grating 223 , and the second lens 224 are arranged in this order from the objective lens 21 side.

The imaging part 23 is comprised by the imaging element 231 which has a two-dimensional light-receiving surface. Such an imaging device 231 is, for example, a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The imaging unit 23 generates the two-dimensional image P based on the measurement light received from the imaging spectrometer 22 . The two-dimensional image P generated by the imaging unit 23 includes wavelength information and position information.

For example, the polarizing plate 50 is disposed on the optical path of the measurement light from the target region R to the objective lens 21 . The polarizing plate 50 has an absorption axis. For example, the polarizing plate 50 is fixed on the optical path using a fixing member such as a bolt so that the direction of the absorption axis can be adjusted and the relative position with the light receiving optical system 20 is fixed.

The direction of the absorption axis of the polarizing plate 50 on a plane that intersects with the optical path of the measurement light is adjusted by, for example, the adjustment unit 51 before inline measurement of the transmittance spectrum of the measurement object S is started. In addition, the direction may be manually adjusted by the user.

The polarizing plate 50 absorbs the light which vibrates in the direction parallel to an absorption axis among the measurement light from the target area|region R. Light passing through the polarizing plate 50 is guided to the objective lens 21 .

The objective lens 21 converges the light transmitted through the polarizing plate 50 among the measurement light from the target region R and guides it to the imaging spectrometer 22 .

The slit portion 221 in the imaging spectrometer 22 includes a slit. The slit portion 221 shapes the beam cross section of the measurement light incident on it through the objective lens 21 into a predetermined shape. The length in the longitudinal direction of the slit in the slit portion 221 is set to a length corresponding to the length of the target region R, and the width in the width direction of the slit is set according to the resolution of the diffraction grating 223 or the like.

The first lens 222 in the imaging spectrometer 22 converts the measurement light passing through the slit portion 221 into parallel light, and guides the converted measurement light to the diffraction grating 223 . The first lens 222 is, for example, a collimating lens.

In the diffraction grating 223 of the imaging spectrometer 22, the wavelength of the measurement light is expanded in a direction orthogonal to the longitudinal direction of the measurement light (Wave length Expansion). More specifically, the diffraction grating 223 expands the wavelength of the line-shaped measurement light passing through the slit 221 in a direction orthogonal to the line direction, that is, it scatters.

The second lens 224 of the imaging spectrometer 22 uses the measurement light wavelength-developed by the diffraction grating 223 as a two-dimensional optical spectrum reflecting wavelength information and position information in the imaging unit 23 . The image is formed on the light-receiving surface of the imaging device 231 of

The imaging unit 23 transmits two-dimensional image data representing the two-dimensional image P imaged on the light-receiving surface of the imaging element 231 to the processing device 30 as a light reception result in the light-receiving optical system 20 .

Below, the D1 direction in FIG. 3 in the two-dimensional image P is called a "position direction", and the D2 direction which is a direction orthogonal to a position direction is called a "wavelength direction." Each point in the position direction corresponds to each measurement point X on the target area R. Each point in the wavelength direction corresponds to the wavelength of the measurement light from the corresponding measurement point X. In addition, it is assumed that the light-receiving surface of the imaging element 231 has m channels as a resolution in the wavelength direction and n channels as a resolution in the position direction. n is 1200, for example.

[processing unit]

4 is a diagram showing the configuration of a processing device in the optical measuring device according to the first embodiment of the present invention.

With reference to FIG. 4 , the processing device 30 includes a reception unit 31 , a calculation unit 32 , a storage unit 33 , and a transmission unit 34 . The processing device 30 is, for example, a personal computer. The reception unit 31 , the calculation unit 32 , and the transmission unit 34 are realized by, for example, a processor such as a CPU (Central Processing Unit) and a DSP (Digital Signal Processor). The storage unit 33 is, for example, a nonvolatile memory.

The receiving unit 31 receives the two-dimensional image data from the imaging unit 23 in the light receiving optical system 20 , and stores the received two-dimensional image data in the storage unit 33 .

The calculation unit 32 generates a light reception spectrum S(λ) that is a relationship between the wavelength λ in the target region R and the intensity of the measurement light based on the light reception result of the measurement light in the light reception optical system 20 . And the calculation part 32 calculates the transmittance|permeability for each wavelength of the measurement object S passing through the target area|region R based on the generated light reception spectrum S(λ).

More specifically, the calculation unit 32 generates a light reception spectrum S(λ) based on the two-dimensional image data stored in the storage unit 33, and based on the generated light reception spectrum S(λ), the measurement object S Calculate the transmittance for each wavelength λ of .

For example, the calculation unit 32 calculates that the reference spectrum Str (λ), which is the light reception spectrum S (λ) based on the measurement light generated from the target region R when the measurement object S does not exist, and the measurement object S are Based on the measurement spectrum Stm (λ) which is the light reception spectrum S (λ) based on the measurement light generated from the target region R when present, the transmittance spectrum ST (λ) which is the relationship between the wavelength λ and the transmittance of the measurement target S Calculate.

For example, the calculation unit 32 calculates the film thickness of the measurement target S based on the calculated transmittance spectrum ST(λ). More specifically, the calculation unit 32 generates a power spectrum by performing calculation processing such as a Fourier transform on the calculated transmittance spectrum ST(λ). And the calculation part 32 determines the optical film thickness corresponding to the peak wavelength in the produced|generated power spectrum as the film thickness of the measurement object S.

For example, the calculation unit 32 generates a plurality of reference spectra Str (λ) and a plurality of measurement spectra Stm (λ) for each measurement point X in the target region R, and each generated reference spectrum Str (λ) ) and each measurement spectrum Stm (λ), a plurality of transmittance spectra ST (λ) for each measurement point X are calculated. And the calculation part 32 produces|generates the film thickness distribution which shows the film thickness in each measurement point X of the measurement object S based on each calculated transmittance|permeability spectrum ST(λ).

In addition, the calculation unit 32 may be configured to calculate the hue of the measurement object S based on the calculated transmittance spectrum ST(λ).

(Adjustment processing of absorption axis direction of polarizing plate)

The adjustment part 51 can adjust the direction of the absorption axis of the polarizing plate 50 as a direction on the plane which intersects with respect to the optical path of measurement light. More specifically, the adjustment unit 51 can adjust the direction of the absorption axis of the polarizing plate 50 as a direction on a plane orthogonal to the optical path of the measurement light. The adjustment unit 51 is, for example, an electric actuator, a hydraulic actuator, a pneumatic actuator, a chemical actuator, a magnetic fluid actuator, or an electric viscous fluid actuator. As an example, the adjustment unit 51 is configured to absorb the polarizing plate 50 such that the angle between the absorption axis of the polarizing plate 50 and the optical axis of the measurement object S is -10 degrees or more and 10 degrees or less, or 80 degrees or more and 100 degrees or less. Adjust the direction of the axis.

For example, in the power spectrum generated by performing calculation processing, such as a Fourier transform, on the transmittance spectrum of the measurement object S, the adjustment part 51 WHEREIN: As a single peak not buried in the background shows, the absorption of the polarizing plate 50 Adjust the direction of the axis.

For example, before starting the inline measurement of the transmittance spectrum of the measurement object S, the adjustment unit 51 adjusts the direction of the absorption axis of the polarizing plate 50 according to the control signal from the processing device 30 .

More specifically, before starting the in-line measurement of the transmittance spectrum of the measurement object S, the calculation unit 32 determines a predetermined reference direction on a plane orthogonal to the optical path of the measurement light and a predetermined reference direction on the plane. A control signal for adjusting the angle θa formed by the direction of the absorption axis of the polarizing plate 50 as the direction to the initial angle θas is output to the transmitter 34 .

When receiving the control signal from the calculation unit 32 , the transmission unit 34 transmits the received control signal to the adjustment unit 51 .

For example, when receiving a control signal from the transmitting unit 34 , the adjusting unit 51 adjusts the angle θa to the angle θas by rotating the polarizing plate 50 according to the received control signal.

When the angle θa is adjusted by the adjustment unit 51 , the calculation unit 32 calculates the transmittance spectrum ST(λ) at a certain measurement position M in the measurement object S. For example, in the measurement position M, the calculation part 32 calculates the transmittance|permeability spectrum ST(λ) in the part located at the edge part of the longitudinal direction of the target area|region R. Next, the calculation unit 32 generates a power spectrum by performing calculation processing such as a Fourier transform on the calculated transmittance spectrum ST(λ). Then, the calculator 32 calculates the difference D between the intensity of the largest peak and the intensity of the second largest peak in the generated power spectrum. The calculation unit 32 stores the calculated difference D in the storage unit 33 .

In addition, when the difference D is stored in the storage unit 33, the calculation unit 32 transmits a control signal for changing the angle θa to an angle rotated by 3 degrees clockwise, for example, via the transmission unit 34 via the adjustment unit ( 51) is sent to

The adjustment unit 51, upon receiving the control signal from the calculation unit 32 via the transmission unit 34, adjusts the angle θa again according to the received control signal.

When the angle θa is adjusted by the adjustment unit 51, the calculation unit 32 again calculates the transmittance spectrum ST(λ) at the measurement position M in the measurement object S and generates a power spectrum, The difference D in the power spectrum is calculated.

As described above, the calculation unit 32 calculates the difference D for each angle θa by repeating the change of the angle θa and the calculation of the difference D in the power spectrum a predetermined number of times, for example, 60 times. And the calculation part 32 detects the angle θmax which is the angle θa when the difference D becomes the maximum.

When the angle θmax is detected, the calculation unit 32 transmits a control signal for setting the angle θa to the angle θmax to the adjustment unit 51 via the transmission unit 34 . Further, the calculation unit 32 detects one or more angles θth that are the angles θa when the difference D is equal to or greater than a predetermined threshold, and transmits a control signal for setting the angle θa to a certain angle θth via the transmission unit 34 . It may be configured to transmit to the furnace adjustment unit 51 . Further, the calculation unit 32, based on the index indicating the sharpness of the peak appearing in the power spectrum, detects the angle θa when the sharpest single peak appears as the angle θmax, and controls for setting the detected angle θmax A configuration in which a signal is transmitted to the adjustment unit 51 via the transmission unit 34 may be employed.

When receiving the control signal from the calculation unit 32 via the transmission unit 34 , the adjustment unit 51 rotates the polarizing plate 50 so that the angle θa becomes the angle θmax according to the received control signal.

The optical measuring device 101 starts inline measurement of the transmittance spectrum ST(λ) of the measurement object S in a state where the angle θa is set to the angle θmax.

For example, the optical measuring device 101 is used for measuring the film thickness of the measurement object S having birefringence. Specifically, the measurement object S is, for example, a stretched film of PET (Polyethylene Terephthalate). The stretched film of PET has an optical axis, for example, a slow axis Nx and a fast axis Ny, according to an extending|stretching direction and a draw ratio. The slow axis Nx and the fast axis Ny are orthogonal, for example. The slow axis Nx and the fast axis Ny of the measurement object S are examples of the optical axis of the measurement object S.

Moreover, for example, the optical measuring apparatus 101 is used for the film thickness measurement of the measurement object S which has a polarization characteristic. Specifically, the measurement target S is, for example, a long polarizing film. A polarizing film is extended|stretched in a manufacturing process, and has an absorption axis in the direction along an extending|stretching direction. The absorption axis of the measurement object S is an example of the optical axis of the measurement object S.

In the conventional optical measurement method, when measuring the film thickness of the measurement object S which has birefringence or polarization characteristic, it may not be able to measure the film thickness of the measurement object S accurately. Specifically, for example, in the conventional optical measurement method, the beat component is included in the transmittance spectrum calculated under the influence of the birefringence of the measurement object S, and the power spectrum obtained by Fourier transforming the transmittance spectrum. , as peaks corresponding to the film thickness of the measurement object S, a plurality of peaks may occur at different positions, and in this case, it is difficult to accurately measure the film thickness of the measurement object S. For example, in the conventional optical measurement method, a peak corresponding to the film thickness of the measurement object S may be buried in the background in the power spectrum due to the influence of the birefringence of the measurement object S, in this case, It is difficult to accurately measure the film thickness of the measurement object S. For example, in the conventional optical measurement method, a peak corresponding to the film thickness of the measurement object S may be buried in the background in the power spectrum due to the influence of the polarization property of the measurement object S, in this case , it is difficult to accurately measure the film thickness of the measurement object S.

Moreover, in the technique described in patent document 3 and patent document 4, in order to measure the retardation of a measurement object, a polarizing plate is arrange|positioned so that both the light irradiated to a measurement object and the light output from a measurement object may pass through the polarizing plate. Therefore, since both the light irradiated to the measurement object and the light output from the measurement object are attenuated by the polarizing plate, the film thickness may not be accurately measured within a limited measurement time.

(Measurement Example 1)

Fig. 5 is a diagram showing a transmittance spectrum generated by the optical measuring apparatus according to Comparative Example 1 of the first embodiment of the present invention. In Fig. 5, the vertical axis is transmittance, and the horizontal axis is wavelength. 5 : has shown the transmittance|permeability spectrum STc1 ((lambda)) in a certain measuring point on the measurement object S which has birefringence produced|generated by the optical measuring apparatus 101 which does not include the polarizing plate 50. As shown in FIG.

6 is a diagram showing a power spectrum of a transmittance spectrum generated by the optical measuring device according to Comparative Example 1 of the first embodiment of the present invention. In FIG. 6 , the vertical axis indicates strength, and the horizontal axis indicates film thickness. FIG. 6 : has shown the power spectrum Pwc1 obtained by Fourier transforming the transmittance|permeability spectrum STc1 ((lambda)) shown in FIG.

Referring to Fig. 6, in the power spectrum Pwc1 generated by the optical measuring device 101 according to Comparative Example 1, a peak that will appear depending on the film thickness of the measurement object S is buried in the background, so that the largest peak is uniquely cannot be detected For this reason, it is difficult to accurately measure the film thickness of the measurement object S.

Fig. 7 is a diagram showing a transmittance spectrum generated by the optical measuring apparatus according to Comparative Example 2 of the first embodiment of the present invention. In Fig. 7, the vertical axis is transmittance, and the horizontal axis is wavelength. 7 shows a certain measurement point on the measurement object S having birefringence generated by the optical measurement apparatus 101 in which the angle between the direction of the absorption axis of the polarizing plate 50 and the direction of the slow axis Nx of the measurement object S is 45 degrees. The transmittance spectrum STc2 (λ) is shown.

Fig. 8 is a diagram showing a power spectrum of a transmittance spectrum generated by the optical measuring apparatus according to Comparative Example 2 of the first embodiment of the present invention. In FIG. 8 , the vertical axis indicates strength, and the horizontal axis indicates film thickness. 8 : has shown the power spectrum Pwc2 obtained by Fourier transforming the transmittance|permeability spectrum STc2 ((lambda)) shown in FIG.

Referring to FIG. 8 , in the power spectrum Pwc2 generated by the optical measuring device 101 according to Comparative Example 2, like the power spectrum Pwc1, a peak to appear depending on the film thickness of the measurement object S is buried in the background, and the most A large peak may not be uniquely detectable. In this case, it is difficult to accurately measure the film thickness of the measurement object S.

9 is a diagram showing a transmittance spectrum generated by the optical measuring device according to the first embodiment of the present invention. In Fig. 9, the vertical axis is transmittance, and the horizontal axis is wavelength. Fig. 9 shows any on the measurement object S having birefringence generated by the optical measurement apparatus 101 adjusted so that the direction of the absorption axis of the polarizing plate 50 is parallel to the direction of the slow axis Nx of the measurement object S The transmittance spectrum ST (λ) at the measurement point is shown.

Fig. 10 is a diagram showing a power spectrum of a transmittance spectrum generated by the optical measuring device according to the first embodiment of the present invention. In Fig. 10, the vertical axis is strength, and the horizontal axis is film thickness. FIG. 10 : has shown the power spectrum Pw obtained by Fourier transforming the transmittance|permeability spectrum ST ((lambda)) shown in FIG.

Referring to Fig. 10, in the power spectrum Pw generated by the optical measuring apparatus 101 according to the first embodiment of the present invention, the largest peak pk can be uniquely detected, and the measurement object corresponding to the peak pk The film thickness F of S can be measured accurately.

(Measurement Example 2)

11 is a diagram showing a transmittance spectrum generated by the optical measuring device according to Comparative Example 3 of the first embodiment of the present invention. 11 , the vertical axis indicates transmittance, and the horizontal axis indicates wavelength. 11 shows a certain measurement point on the measurement object S having birefringence, which is generated by the optical measurement apparatus 101 in which the angle between the direction of the absorption axis of the polarizing plate 50 and the direction of the slow axis Nx of the measurement object S is 45 degrees. The transmittance spectrum STc3 (λ) is shown.

12 is a diagram showing a power spectrum of a transmittance spectrum generated by the optical measuring device according to Comparative Example 3 of the first embodiment of the present invention. In FIG. 12 , the vertical axis indicates strength, and the horizontal axis indicates film thickness. 12 : has shown the power spectrum Pwc3 obtained by Fourier transforming the transmittance|permeability spectrum STc3 ((lambda)) shown in FIG.

With reference to FIG. 12, in the power spectrum Pwc3 produced|generated by the optical measuring apparatus 101 which concerns on the comparative example 3, peaks pk1, pk2 generate|occur|produce, and the largest peak may not be uniquely detectable. In this case, it is difficult to accurately measure the film thickness of the measurement object S.

Fig. 13 is a diagram showing a transmittance spectrum generated by the optical measuring apparatus according to Comparative Example 4 of the first embodiment of the present invention. In Fig. 13, the vertical axis is transmittance, and the horizontal axis is wavelength. 13 shows a certain measurement point on the measurement object S having birefringence, which is generated by the optical measurement apparatus 101 in which the angle between the direction of the absorption axis of the polarizing plate 50 and the direction of the slow axis Nx of the measurement object S is 75 degrees. The transmittance spectrum STc4 (λ) is shown.

Fig. 14 is a diagram showing the power spectrum of the transmittance spectrum generated by the optical measuring device according to Comparative Example 4 of the first embodiment of the present invention. In Fig. 14, the vertical axis is strength, and the horizontal axis is film thickness. 14 : has shown the power spectrum Pwc4 obtained by Fourier transforming the transmittance|permeability spectrum STc4 ((lambda)) shown in FIG.

With reference to FIG. 14 , in the power spectrum Pwc4 generated by the optical measuring device 101 according to Comparative Example 4, the peaks pk1 and pk2 are generated similarly to the power spectrum Pwc3. The peak pk2 in the power spectrum Pwc4 is smaller than the peak pk2 in the power spectrum Pwc3. However, in the power spectrum Pwc4, the largest peak may not be uniquely detected depending on the measurement conditions or the like. In this case, it is difficult to accurately measure the film thickness of the measurement object S.

15 is a diagram showing a transmittance spectrum generated by the optical measuring device according to the first embodiment of the present invention. In Fig. 15, the vertical axis is transmittance, and the horizontal axis is wavelength. 15 shows a certain measurement point on the measurement object S having birefringence, which is generated by the optical measurement apparatus 101 in which the angle between the direction of the absorption axis of the polarizing plate 50 and the direction of the slow axis Nx of the measurement object S is 90 degrees. The transmittance spectrum ST2 (λ) in .

16 is a diagram showing a power spectrum of a transmittance spectrum generated by the optical measuring device according to the first embodiment of the present invention. In Fig. 16, the vertical axis is strength, and the horizontal axis is film thickness. FIG. 16 : has shown the power spectrum Pw2 obtained by Fourier transforming the transmittance|permeability spectrum ST2 ((lambda)) shown in FIG.

Referring to Fig. 16, in the power spectrum Pw2 generated by the optical measuring apparatus 101 according to the first embodiment of the present invention, the largest peak pk1 can be uniquely detected, and the measurement object corresponding to the peak pk1 The film thickness F of S can be measured accurately.

It is a figure which shows the relationship between the direction of the absorption axis of a polarizing plate in the optical measuring apparatus which concerns on 1st Embodiment of this invention, and the direction of the slow axis of a measurement object.

Referring to FIG. 17 , the irradiation optical system 10 irradiates the measurement object S with irradiation light, which is natural light. The transmitted light passing through the measurement object S contains the light Lx which vibrates in a direction parallel to the slow axis Nx of the measurement object S, and the light Ly which vibrates in a direction parallel to the fast axis Ny of the measurement object S.

For example, the peak pk1 in the power spectra Pwc3 and Pwc4 is a peak corresponding to light Lx, and the peak pk2 in the power spectra Pwc3 and Pwc4 is a peak corresponding to light Ly.

The optical measuring device 101 according to Comparative Example 3 receives the light Lx attenuated by the polarizing plate 50 and the light Ly attenuated by the polarizing plate 50 . Here, since the angle between the direction of the absorption axis of the polarizing plate 50 in the optical measuring device 101 according to Comparative Example 3 and the direction of the slow axis Nx of the measurement object S is 45 degrees, the polarizing plate 50 The attenuation amount of the light Lx and the attenuation amount of the light Ly by the polarizing plate 50 are approximately the same. Therefore, in the power spectrum Pwc3 generated by the optical measuring device 101 according to Comparative Example 3, the peak pk1 corresponding to the light Lx and the peak pk2 corresponding to the light Ly and having the same magnitude as the peak pk1 are generated. .

In addition, the optical measuring device 101 according to Comparative Example 4 receives the light Lx attenuated by the polarizing plate 50 and the light Ly attenuated by the polarizing plate 50 . Here, since the angle between the direction of the absorption axis of the polarizing plate 50 in the optical measuring device 101 according to Comparative Example 4 and the direction of the slow axis Nx of the measurement object S is 75 degrees, the polarizing plate 50 The attenuation amount of the light Ly is larger than the attenuation amount of the light Lx by the polarizing plate 50 . Therefore, in the power spectrum Pwc4 generated by the optical measuring device 101 according to Comparative Example 4, the peak pk1 corresponding to the light Lx and the peak pk2 corresponding to the light Ly and smaller than the peak pk1 are generated.

On the other hand, since the angle formed by the direction of the absorption axis of the polarizing plate 50 in the optical measuring apparatus 101 which concerns on 1st Embodiment and the direction of the slow axis Nx of the measurement object S is 90 degrees, it is shown in FIG. As shown, the light Lx is not attenuated by the polarizing plate 50 and passes through the polarizing plate 50 , while the light Ly is absorbed by the polarizing plate 50 . Therefore, in the power spectrum Pw2 generated by the optical measuring device 101 according to the first embodiment, the peak pk1 corresponding to the light Lx is generated, while the peak corresponding to the light Ly is not generated, so that the largest The peak pk1 can be uniquely detected, and the film thickness F of the measurement object S corresponding to the peak pk1 can be accurately measured.

[Modified Example 1]

The calculation part 32 calculates the film thickness of the measurement object S based on the light reception result of each measurement light when the direction of the absorption axis of a polarizing plate on the plane orthogonal to the optical path of irradiation light differs.

For example, in the state where the angle θa is set to the angle θmax, the calculation unit 32 calculates the film thickness Fmax1 calculated based on the light reception result by the light receiving optical system 20 of the measurement light generated from the measurement position M, and the angle The average value of the film thickness Fmax2 calculated based on the light reception result by the light receiving optical system 20 of the measurement light generated from the measurement position M in a state where θa is set at the angle (θmax + 90°) is the film thickness of the measurement object S decide as

For example, the direction Da of the absorption axis of the polarizing plate 50 in a state where the angle θa is set to the angle θmax is a direction parallel to the slow axis Nx of the measurement object S, and the angle θa is the angle (θmax + 90°) The direction Db of the absorption axis of the polarizing plate 50 in the set state is a direction parallel to the fast axis Ny of the measurement object S.

More specifically, the optical measuring apparatus 101 includes an irradiation optical system 10a and an irradiation optical system 10b arranged along the conveyance direction of the measurement object S, and a light receiving optical system 20a arranged along the conveyance direction of the measurement object S. ) and a light receiving optical system 20b.

The irradiation optical system 10a and the irradiation optical system 10b irradiate irradiation light to the measurement position M in the measurement object S.

The light receiving optical system 20a receives the measurement light generated from the measurement position M by irradiation of the irradiation light with respect to the measurement position M by the irradiation optical system 10a. The light receiving optical system 20b receives the measurement light generated from the measurement position M by irradiation of the irradiation light with respect to the measurement position M by the irradiation optical system 10b.

The direction Da of the absorption axis of the polarizing plate 50 in the light receiving optical system 20a and the direction Db of the absorption axis of the polarizing plate 50 in the light receiving optical system 20b are orthogonal to each other. More specifically, the absorption axis of the polarizing plate 50 in the light receiving optical system 20a has an angle θa set to an angle θmax, and the absorption axis of the polarizing plate 50 in the light receiving optical system 20b has an angle θa The angle (θmax + 90°) is set.

The calculation unit 32 has a film thickness Fmax1 calculated on the basis of the light reception result by the light receiving optical system 20a of the measurement light generated from the measurement position M, and the measurement light generated from the measurement position M is received by the light receiving optical system 20b. The average value of the film thickness Fmax2 calculated based on the result is determined as the film thickness of the measurement object S.

[Modified Example 2]

In addition, in the optical measurement apparatus 101 which concerns on 1st Embodiment of this invention, although the polarizing plate 50 was set as the structure which is fixedly formed only in the light receiving optical system 20, it is not limited to this. The polarizing plate 50 may be configured to be fixedly formed only in the irradiation optical system 10 .

Fig. 18 is a diagram showing an example of the configuration of an optical measuring device according to Modification Example 2 of the first embodiment of the present invention.

Referring to FIG. 18 , in the optical measuring apparatus 101 , the light receiving optical system 20 does not include the polarizing plate 50 , while the irradiation optical system 10 includes the polarizing plate 50 .

In more detail, for example, the polarizing plate 50 is arrange|positioned on the optical path of the irradiation light from the line light guide 12 to the target area|region R. For example, the polarizing plate 50 is fixed on the said optical path using fixing members, such as a bolt, so that the direction of an absorption axis can be adjusted, and the relative position with the irradiation optical system 10 may be fixed.

The adjustment unit 51 adjusts the direction of the absorption axis of the polarizing plate 50 on a plane orthogonal to the optical path of the irradiated light.

In the optical measuring device 101 according to the second modification, the largest peak pk can be uniquely detected in the generated power spectrum Pw, similarly to the optical measuring device 101 according to the first embodiment of the present invention. Therefore, the film thickness F of the measurement object S corresponding to the peak pk can be accurately measured.

[Flow of Motion]

An optical measuring apparatus according to an embodiment of the present invention includes a computer including a memory, and an arithmetic processing unit such as a CPU in the computer executes a program including a part or all of each step of the flowchart below. Read and output from memory and execute. The program of this device can be installed from outside. The program of this apparatus is distributed in the state stored in the recording medium.

19 is a flowchart illustrating an example of an operation procedure for calculating a film thickness of a measurement object in the optical measurement apparatus according to Modification Example 1 of the first embodiment of the present invention.

Referring to FIG. 19 , first, the optical measurement device 101 performs calculation processing such as Fourier transform on the transmittance spectrum of the measurement object S before starting inline measurement of the transmittance distribution of the measurement object S. A power spectrum generated by In , the direction of the absorption axis of each polarizing plate 50 of the light receiving optical systems 20a, 20b is adjusted as indicated by the single peak not buried in the background. Specifically, the optical measuring device 101 is an angle formed by a predetermined reference direction on a plane orthogonal to the optical path of the measurement light and the direction of the absorption axis of the polarizing plate 50 in the light receiving optical system 20a. Let θa be the angle θmax. In addition, the optical measuring device 101 calculates an angle θa formed by a predetermined reference direction on a plane orthogonal to the optical path of the measurement light and the direction of the absorption axis of the polarizing plate 50 in the light receiving optical system 20b. angle (θmax + 90°) (step S102).

Next, after the inline measurement is started, the optical measurement device 101 waits for a measurement timing that is a timing to be measured (NO in step S104), and at the measurement timing (YES in step S104), the light irradiated to the measurement object S is investigated in a straight line. Specifically, the optical measurement apparatus 101 irradiates the irradiation light linearly to the measurement position M in the measurement object S using the irradiation optical systems 10a, 10b (step S106).

Next, the optical measurement device 101 receives the measurement light, ie, transmitted light, which is generated from the measurement object S by irradiation of the measurement object S and transmitted through the polarizing plate 50 . Specifically, the optical measurement device 101 receives the transmitted light passing through the measurement object S using the light-receiving optical systems 20a and 20b (step S108).

Next, the optical measuring device 101 calculates the transmittance spectrum ST (λ) based on the light reception result of the measurement light. Specifically, the optical measuring device 101 has a transmittance spectrum ST (λ) based on the light reception result by the light receiving optical system 20a and a transmittance spectrum ST (λ) based on the light reception result by the light receiving optical system 20b . is calculated (step S110).

Next, the optical measurement apparatus 101 calculates the film thickness at the measurement position M of the measurement object S based on each calculated transmittance|permeability spectrum ST(λ). Specifically, the optical measuring device 101 is the average value of the film thickness Fmax1 calculated based on the light reception result by the light receiving optical system 20a and the film thickness Fmax2 calculated based on the light receiving result by the light receiving optical system 20b is determined as the film thickness at the measurement position M of the measurement object S (step S112).

Further, in the optical measuring device 101 according to the first embodiment of the present invention, when the film thickness of the measurement object is calculated using a pair of the irradiation optical system 10a and the light receiving optical system 20a, the light receiving optical system Setting the direction of the absorption axis of the polarizing plate 50 in (20b) (step S102), irradiation of irradiation light using the irradiation optical system 10b (step S106), and reception of transmitted light using the light receiving optical system 20b (step S108) , and it is not necessary to calculate the transmittance spectrum ST (λ) based on the light reception result by the light receiving optical system 20b (step S110), and the film thickness Fmax1 calculated based on the light receiving result by the light receiving optical system 20a is What is necessary is just to determine as the film thickness of the measurement position M of the measurement object S (step S112). Moreover, when calculating the film thickness of a measurement object using the optical measurement apparatus 101 which concerns on the modified example 2 of 1st Embodiment of this invention, the optical measurement apparatus 101 is the measurement object S in step S106. The irradiation light transmitted through the polarizing plate 50 is irradiated linearly, and the measurement light which has not passed through the polarizing plate 50 is received in step S108.

20 is a flowchart illustrating an example of an operation procedure when adjusting the direction of the absorption axis of the polarizing plate in the optical measuring device according to the first embodiment of the present invention. Fig. 20 shows the details of step S102 in Fig. 19 .

With reference to FIG. 20 , first, the optical measuring device 101 adjusts the angle θa to the angle θas which is an initial value by rotating the polarizing plate 50 (step S202).

Next, the optical measurement device 101 calculates the transmittance spectrum ST (λ) at a certain measurement position M in the measurement object S, and performs calculation processing such as Fourier transform on the calculated transmittance spectrum ST (λ) By carrying out, a power spectrum is generated (step S204).

Next, the optical measuring device 101 calculates a difference D between the intensity of the largest peak and the intensity of the second largest peak in the generated power spectrum, and stores the calculated difference D in the storage unit 33 . to save (step S206).

Next, the optical measurement apparatus 101 rotates the polarizing plate 50 to the angle which rotated the angle θa clockwise by 3 degrees, when the number of times of processing in steps S204 and S206 is less than the predetermined number (NO in step S208). Adjustment is performed (step S210), and steps S204 and S206 are repeated.

Next, the optical measurement apparatus 101 detects the angle θmax that is the angle θa when the difference D becomes the maximum when the number of times of processing in steps S204 and S206 reaches the predetermined number (YES in step S208) (step S208). S212).

Next, the optical measuring apparatus 101 rotates the polarizing plate 50 so that the angle θa becomes the angle θmax (step S214).

In addition, in the optical measuring device 101 according to the first embodiment of the present invention, the irradiation optical system 10 is configured to irradiate the target region R, which is a linear region through which the measurement target S passes, with irradiation light. It is not limited. The irradiation optical system 10 may be configured to irradiate irradiation light to a point-like target position.

Moreover, although the optical measuring apparatus 101 which concerns on 1st Embodiment of this invention was set as the structure provided with the adjustment part 51, it is not limited to this. The optical measuring device 101 may be configured not to include the adjustment unit 51 . In this case, as an example, the direction of the absorption axis of the polarizing plate 50 is fixed in advance so as to be parallel to the direction of the slow axis Nx or the fast axis Ny of the measurement object S on a plane orthogonal to the optical path of the measurement light.

In addition, in the optical measuring device 101 according to the first embodiment of the present invention, the adjusting unit 51 adjusts the direction of the absorption axis of the polarizing plate 50 according to the control signal received from the transmitting unit 34. However, it is not limited thereto. The adjustment part 51 is not limited to automatic adjustment, The structure which has the mechanism which can manually adjust the direction of the absorption axis of the polarizing plate 50 may be sufficient. In this case, the user manually adjusts the angle θa in steps S202 and S210 of FIG. 20 .

In addition, in the optical measuring device 101 according to the first embodiment of the present invention, the polarizing plate 50 is arranged on the optical path of the measurement light from the target region R to the objective lens 21, but limited to this it is not The polarizing plate 50 is disposed between the objective lens 21 and the slit portion 221 , between the slit portion 221 and the first lens 222 , or between the first lens 222 and the diffraction grating 223 . configuration may be sufficient.

Moreover, in the optical measuring apparatus 101 which concerns on 1st Embodiment of this invention, although the polarizing plate 50 was set as the structure which is fixedly formed only in either one of the irradiation optical system 10 and the light receiving optical system 20, limited to this it's not going to be

For example, the optical measuring device 101 includes a polarizing plate 50A that is a polarizing plate 50 formed in the irradiation optical system 10 , and a polarizing plate 50B that is a polarizing plate 50 formed in the light receiving optical system 20 . configuration may be used. More specifically, the polarizing plate 50A is arranged on the optical path OP1 of the irradiated light from the line light guide 12 to the target area R by, for example, a stand S1 having a support clamp, and the polarizing plate 50B is For example, it is arranged on the optical path OP2 of the measurement light from the target region R to the objective lens 21 by a stand S2 having a support clamp. In this case, when starting the film thickness measurement of the measurement object S, for example, depending on the type of the measurement object S, the user moves the polarizing plate 50A to a position deviated from the optical path OP1, or the polarizing plate 50B moves the optical path It is moved to a position away from OP2. In addition, the polarizing plate 50A or the polarizing plate 50B may be mounted on an actuator (not shown) that receives a control signal from the processing device 30, and is automatically moved in accordance with the operation of the actuator.

Moreover, for example, the optical measuring device 101 may be a structure provided with the polarizing plate 50C which is the movable polarizing plate 50 formed in either one of the irradiation optical system 10 and the light receiving optical system 20. More specifically, the polarizing plate 50C is mounted on an actuator (not shown) that receives a control signal from the processing device 30, and automatically moves between the optical paths OP1 and OP2 in accordance with the operation of the actuator. , disposed on the optical path OP1 or on the optical path OP2. Further, the polarizing plate 50C may be arranged on the optical path OP1 or at the predetermined position by automatically moving between the optical path OP1 and a predetermined position deviating from the optical path OP1 in accordance with the operation of the actuator. Alternatively, the polarizing plate 50C may be configured to be disposed on the optical path OP2 or at the predetermined position by automatically moving between the optical path OP2 and a predetermined position deviating from the optical path OP2 with the operation of the actuator.

Next, embodiment other than this invention is demonstrated using drawings. In addition, the same code|symbol is attached|subjected to the same or corresponding part in a figure, and the description is not repeated.

<Second embodiment>

The present embodiment relates to an optical measuring device 102 using reflected light generated from the target region R as compared with the optical measuring device 101 according to the first embodiment. Except for the content described below, it is the same as the optical measuring device 101 according to the first embodiment.

[Optical measuring device]

Fig. 21 is a diagram showing an example of the configuration of the optical measuring device according to the second embodiment of the present invention.

Referring to FIG. 21 , the optical measuring device 102 includes an irradiation optical system 10 , a light receiving optical system 20 , a processing device 30 , an adjustment unit 51 , a base member 4 , and a support member. (6) and a polarizing plate 50 are provided. The base member 4 and the supporting member 6 fix the light receiving optical system 20 . In addition, the optical measuring apparatus 102 is not limited to the structure provided with the base member 4 and the support member 6, Instead of the base member 4 and the support member 6, or the base member 4 and another member for fixing the light-receiving optical system 20 in addition to the supporting member 6 may be provided.

The polarizing plate 50 is comprised so that it may be located in either one of the irradiation optical system 10 and the light receiving optical system 20 . For example, the polarizing plate 50 is fixedly formed only in either one of the irradiation optical system 10 and the light receiving optical system 20 . In the example shown in FIG. 21 , the polarizing plate 50 is fixedly formed only in the light receiving optical system 20 .

22 is a diagram showing an example of the configuration of an optical measuring device according to a second embodiment of the present invention. 22 : has shown the state in which the measurement object S which is a measurement object of the optical measurement apparatus 102 is arrange|positioned.

With reference to FIG. 22 , the optical measuring device 102 measures the reflectance spectrum of the measurement object S passing through the target region R .

For example, in the manufacturing line of the measurement object S, the optical measurement apparatus 102 automatically measures the reflectance spectrum in the some measurement position M on the measurement object S conveyed through the target area|region R. That is, the optical measurement apparatus 102 measures the reflectance spectra in the some measurement position M on the measurement object S in-line.

In more detail, the optical measuring apparatus 102 calculates the reflectance for every wavelength in the measurement position M of the measurement object S conveyed, for example by performing a reflectance measurement periodically.

[Irradiation optical system]

The irradiation optical system 10 irradiates the measurement object S with irradiation light including a plurality of wavelengths in a straight line. In more detail, the irradiation optical system 10 irradiates irradiation light to the target area|region R which is a linear area|region through which the measurement object S passes.

The line light guide 12 of the irradiation optical system 10 is arranged so that the incident angle of the irradiation light on the measurement object S passing through the target region R is θ.

[Light-receiving optical system]

The light-receiving optical system 20 receives the measurement light which is the reflected light generated from the measurement object S by irradiation of the irradiation light with respect to the measurement object S.

The light-receiving optical system 20 is disposed on the same side as the line light guide 12 with respect to the measurement object S, and is disposed at a position capable of receiving reflected light having a reflection angle of θ on the measurement object S.

The light receiving optical system 20 includes a polarizing plate 50 , an objective lens 21 , an imaging spectrometer 22 , and an imaging unit 23 .

The polarizing plate 50 is arranged on the optical path of the measurement light from the target region R to the objective lens 21 . The polarizing plate 50 has an absorption axis.

The light receiving optical system 20 receives the reflected light reflected by the measurement object S among the irradiation light emitted from the line light guide 12 as measurement light. Specifically, the light-receiving optical system 20 receives the reflected light of the measurement object S passing through the target region R among the irradiated light emitted from the line light guide 12 .

[processing unit]

The calculation unit 32 of the processing device 30, based on the light reception result of the measurement light in the light receiving optical system 20, is a light reception spectrum S (λ) which is a relationship between the wavelength λ in the target region R and the intensity of the measurement light. ) is created. Then, the calculation unit 32 calculates the reflectance for each wavelength of the measurement object S passing through the target region R based on the generated light reception spectrum S(λ).

More specifically, the calculation unit 32 generates a light reception spectrum S(λ) based on the two-dimensional image data stored in the storage unit 33, and based on the generated light reception spectrum S(λ), the measurement object S Calculate the reflectance for each wavelength λ of

For example, the calculation unit 32 may calculate a reference spectrum Srr(λ) that is a light-receiving spectrum S(λ) based on the measurement light generated from the reflection plate disposed on the target region R in a state where the reflector is disposed on the target region R , and the reflectance spectrum SR (λ) of the measurement object S is calculated based on the measurement spectrum Srm (λ) which is a light reception spectrum S (λ) based on the measurement light generated from the target region R when the measurement object S is present.

For example, the calculation unit 32 calculates the film thickness of the measurement object S based on the calculated reflectance spectrum SR (λ). More specifically, the calculation unit 32 generates a power spectrum by performing calculation processing such as a Fourier transform on the calculated reflectance spectrum SR(λ). And the calculation part 32 determines the optical film thickness corresponding to the peak wavelength in the produced|generated power spectrum as the film thickness of the measurement object S.

For example, the calculation unit 32 generates a plurality of reference spectra Srr (λ) and a plurality of measurement spectra Srm (λ) for each measurement point X in the target region R, and each generated reference spectrum Srr (λ) ) and each measurement spectrum Srm (λ), a plurality of reflectance spectra SR (λ) for each measurement point X are calculated. And the calculation part 32 produces|generates the film thickness distribution which shows the film thickness in each measurement point X of the measurement object S based on each calculated reflectance spectrum SR(λ).

Moreover, in the optical measuring apparatus 102 which concerns on 2nd Embodiment of this invention, the calculation part in the processing apparatus 30 similarly to the optical measuring apparatus 101 which concerns on the modified example of 1st Embodiment of this invention. (32) may be a configuration in which the film thickness of the measurement object S is calculated based on the light reception result of each measurement light when the direction of the absorption axis of the polarizing plate on a plane intersecting with the optical path of the irradiation light is different.

[Modified Example 1]

Fig. 23 is a diagram showing an example of the configuration of an optical measuring apparatus according to Modification Example 1 of the second embodiment of the present invention.

23 , the line light guide 12 has a half mirror 121 . The line light guide 12 irradiates the irradiated light reflected by the half mirror 121 to the target area R. In this case, for example, the line light guide 12 is arrange|positioned just above the surface on which the measurement object S is conveyed so that the incident angle of the irradiation light with respect to the measurement object S passing through the object area|region R may become 0 degrees. That is, the irradiation optical system 10 of the optical measuring device 102 is coaxial reflected illumination.

The light receiving optical system 20 receives the reflected light generated from the measurement object S by irradiation of the irradiation light on the measurement object S through the half mirror 121 . In this case, for example, the light receiving optical system 20 is located at a position where the reflected light having a reflection angle of 0° on the measurement object S can be received, that is, at a position opposite to the target region R with the line light guide 12 interposed therebetween. are placed

[Modified Example 2]

In addition, in the optical measuring apparatus 102 which concerns on 2nd Embodiment of this invention, although the polarizing plate 50 was set as the structure which is fixedly formed only in the light receiving optical system 20, it is not limited to this. The polarizing plate 50 may be configured to be fixedly formed only in the irradiation optical system 10 .

Fig. 24 is a diagram showing an example of the configuration of an irradiation optical system in an optical measuring apparatus according to a modification of the second embodiment of the present invention.

Referring to FIG. 24 , in the optical measuring device 102 , the light receiving optical system 20 does not include the polarizing plate 50 , while the irradiation optical system 10 includes the polarizing plate 50 .

In more detail, the polarizing plate 50 is arrange|positioned on the optical path of the irradiation light from the line light guide 12 to the target area|region R.

In the optical measuring device 102 according to the second embodiment of the present invention, the optical measuring device 102 according to the first modification, and the optical measuring device 102 according to the second modification according to the first embodiment of the present invention, Similar to the optical measurement device 101, in the generated power spectrum Pw, the largest peak pk can be uniquely detected, and the film thickness F of the measurement object S corresponding to the peak pk can be accurately measured.

It should be thought that the said embodiment is an illustration in every point, and is not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

10: irradiation optical system
20: light receiving optical system
30: processing unit
31: receiver
32: output unit
33: memory
34: transmitter
50: polarizer
51: adjustment unit
101, 102: optical measuring device

Claims (6)

An irradiation optical system for irradiating irradiation light including a plurality of wavelengths to a measurement object;
a light-receiving optical system for receiving measurement light that is transmitted light or reflected light generated from the measurement object by irradiation of the irradiated light on the measurement object;
A polarizing plate is provided,
The optical measuring apparatus is comprised so that the said polarizing plate can be located in either one of the said irradiation optical system and the said light-receiving optical system. The method of claim 1,
The optical measurement device, wherein the polarizing plate is fixedly formed only in either one of the irradiation optical system and the light receiving optical system. 3. The method according to claim 1 or 2,
The optical measuring device further
and an adjustment unit capable of adjusting the direction of the absorption axis of the polarizing plate as a direction on a plane intersecting the optical path of the irradiation light or the optical path of the measurement light. An optical measuring method using an optical measuring device including an irradiation optical system and a light receiving optical system, comprising:
a step of irradiating the measurement object with irradiation light including a plurality of wavelengths using the irradiation optical system;
and receiving, using the light-receiving optical system, measurement light that is transmitted light or reflected light generated from the measurement object by irradiation of the irradiated light on the measurement object,
In the step of irradiating the irradiated light to the measurement object or the step of receiving the measurement light, the irradiated light transmitted through a polarizing plate is irradiated to the measurement object, or the measurement light transmitted through the polarizing plate is received. Optics measurement method. 5. The method of claim 4,
The optical measurement method in which the said polarizing plate is fixedly formed only in either one of the said irradiation optical system and the said light-receiving optical system. 6. The method according to claim 4 or 5,
The optical measurement method is further
calculating the film thickness of the measurement object based on the light reception result of each measurement light when the direction of the absorption axis of the polarizing plate is different as a direction on a plane intersecting the optical path of the irradiation light or the measurement light Including, an optical measurement method.

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