Optical measurement device and optical measurement method

Abstract

To more accurately measure the transmittance or reflectance of a measurement object.SOLUTION: An optical measurement device comprises: an illumination optical system irradiating a target area linearly with irradiation light including a plurality of wavelengths; a light-receiving optical system receiving measurement light that is transmitted or reflected light generated from the target area by irradiation of the target area with irradiation light; and a calculation unit generating a light-receiving vector on the basis of the light-receiving result of measurement light in the light-receiving optical system, and calculating transmittance or reflectance per wavelength of a measurement object arranged in a measurement area, on the basis of the generated light-receiving vector. The calculation unit calculates the transmittance or reflectance spectrum of the measurement object on the basis of a first reference spectrum based on measurement light generated from the measurement area when the measurement object does not exist, a second reference spectrum based on measurement light generated from a non-measurement area and a measurement spectrum based on measurement light generated from the measurement area when the measurement object exists.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an optical measurement device and an optical measurement method.

Background Art

[0002] In recent years, a technique for measuring, for example, the film thickness distribution of a measurement object by measuring the transmittance or reflectance of the measurement object based on transmitted light or reflected light generated from the measurement object by irradiating the measurement object with line light is known.

[0003] For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2017-146288) discloses the following film thickness distribution measurement method. That is, the film thickness distribution measurement method is a film thickness distribution measurement method for measuring the film thickness distribution of a thin film wafer having at least one layer of thin film formed on the surface of a substrate by reflection spectroscopy using a line light source, and as the line light source, a line light source having a light source longer than the diameter of the thin film wafer is used, and when scanning the surface of the thin film wafer with linear light irradiated from the line light source and detecting the reflected light, at the same time, irradiating a part of the linear light to a reference and detecting the reflected light thereof; a step of correcting the reflected light intensity from the thin film wafer using the reflected light intensity from the reference; and a step of calculating the film thickness distribution from the corrected reflected light intensity of the thin film wafer.

[0004] In addition, Patent Document 2 (Japanese Patent Application Laid-Open No. 2015-17804) discloses a film thickness distribution measurement method as follows. That is, the film thickness distribution measurement method is a film thickness distribution measurement method for measuring the film thickness distribution of a thin film on a wafer having at least one thin film formed on the surface of a substrate by reflectance spectroscopy using a line light source, and includes the following first, second, and third steps of correcting the incident angle at each point in the line light source direction on the wafer with the thin film, and a fourth step of measuring the film thickness distribution of the thin film on the wafer with the thin film using the corrected incident angle. In the first step, using a wafer with a thin film having a known film thickness, the reflectance at the center of the wafer with the thin film is measured, and a corrected incident angle at the wafer center is calculated from the measured reflectance and the known film thickness. In the second step, using the wafer with the thin film to be measured for the film thickness distribution having a thin film of the same material as the thin film on the wafer used in the first step, and using the corrected incident angle at the wafer center calculated above, while moving the wafer with the thin film in the wafer plane direction perpendicular to the line light source, the film thickness distribution in the region along the wafer center line at the center position of the line light source is measured. In the third step, after rotating the wafer with the thin film by 90° after the second step, the reflectance distribution in the region measured in the second step is measured at each point in the line light source direction, and a corrected incident angle at each point in the line light source direction is calculated from the measured reflectance distribution and the film thickness distribution measured in the second step.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Beyond the technologies of Patent Document 1 and Patent Document 2 as described above, a technology that can more accurately measure the transmittance or reflectance of a measurement object is desired.

[0007] The present invention has been made to solve the above-described problems, and an object thereof is to provide an optical measurement apparatus and an optical measurement method that can more accurately measure the transmittance or reflectance of a measurement object.

Means for Solving the Problems

[0008] (1) In order to solve the above problems, an optical measurement apparatus according to an aspect of the present invention includes an irradiation optical system that linearly irradiates an object region including a measurement region and a non-measurement region that is a region different from the measurement region with irradiation light including a plurality of wavelengths, a light receiving optical system that receives measurement light that is transmitted light or reflected light generated from the object region by the irradiation of the irradiation light to the object region, and based on a light receiving result of the measurement light in the light receiving optical system, generates a light receiving spectrum that is a relationship between a wavelength and an intensity of the measurement light for each position in the object region, and based on the generated light receiving spectrum, calculates a transmittance or reflectance for each wavelength of a measurement object disposed in the measurement region. The calculation unit calculates a transmittance spectrum or a reflectance spectrum of the measurement object based on a first reference spectrum that is the light receiving spectrum based on the measurement light generated from the measurement region when the measurement object does not exist, a second reference spectrum that is the light receiving spectrum based on the measurement light generated from the non-measurement region, and a measurement spectrum that is the light receiving spectrum based on the measurement light generated from the measurement region when the measurement object exists.

[0009] Thus, based on the first reference spectrum based on the measurement light from the measurement region when the object to be measured is absent, the second reference spectrum based on the measurement light from the non-measurement region, and the measurement spectrum based on the measurement light from the measurement region when the object to be measured is present, a transmittance spectrum or a reflectance spectrum of the object to be measured is calculated. For example, by taking into account the temporal changes in the irradiation light intensity and the light reception sensitivity due to the time difference before and after placing the object to be measured in the measurement region, and the variations in the irradiation light intensity and the light reception sensitivity caused by the difference in the irradiation positions between the measurement region and the non-measurement region, etc., the transmittance spectrum or the reflectance spectrum can be calculated from the measurement spectrum. Therefore, the transmittance spectrum or the reflectance spectrum of the object to be measured can be measured more accurately.

[0010] (2) Preferably, the second reference spectrum is a spectrum pre-generated by the calculation unit based on the measurement light generated from the non-measurement region when the object to be measured is not present in the measurement region, and the calculation unit further calculates the transmittance spectrum or the reflectance spectrum of the object to be measured based on a reference spectrum that is the light reception spectrum based on the measurement light generated from the non-measurement region when the object to be measured is present in the measurement region.

[0011] With such a configuration, for example, based on the first reference spectrum, the second reference spectrum, and the reference spectrum, the light reception spectrum that would be generated assuming that the object to be measured was not present in the measurement region at the timing when the measurement spectrum should be generated can be estimated more accurately, and based on the estimated light reception spectrum, the transmittance spectrum or the reflectance spectrum can be calculated more accurately.

[0012] (3) More preferably, the reference spectrum and the measurement spectrum are each spectra generated by the calculation unit based on the measurement light generated from the non-measurement region and the measurement light generated from the measurement region, which are received by the light reception optical system at the same timing when the object to be measured is present in the measurement region.

[0013] With such a configuration, for example, since the influence of temporal changes in the irradiation light intensity and the light reception sensitivity due to the time difference between the timing of generating the reference spectrum and the timing of generating the measurement spectrum can be reduced, the transmittance spectrum or the reflectance spectrum can be calculated more accurately using such a reference spectrum.

[0014] (4) Preferably, the first reference spectrum and the second reference spectrum are spectra generated by the calculation unit based on the measurement light generated from the measurement region and the measurement light generated from the non-measurement region, respectively received by the light reception optical system at the same timing before the measurement object exists in the measurement region.

[0015] With such a configuration, for example, since the influence of temporal changes in the irradiation light intensity and the light reception sensitivity due to the time difference between the timing of generating the first reference spectrum and the timing of generating the second reference spectrum can be reduced, the transmittance spectrum or the reflectance spectrum can be calculated more accurately using such a first reference spectrum and second reference spectrum.

[0016] (5) Preferably, the calculation unit calculates the transmittance spectrum or the reflectance spectrum of the measurement object based on a plurality of the first reference spectra respectively based on the measurement light generated from a plurality of positions in the measurement region when the measurement object does not exist, the second reference spectra, and a plurality of the measurement spectra respectively based on the measurement light generated from the plurality of positions.

[0017] With such a configuration, the transmittance distribution or the reflectance distribution of the measurement object in the measurement region can be measured.

[0018] (6) To solve the above problems, an optical measurement method according to an aspect of the present invention includes: irradiating a target region including a measurement region and a non-measurement region, which is a region different from the measurement region, with linearly polarized irradiation light including a plurality of wavelengths; receiving measurement light, which is transmitted light or reflected light generated from the target region due to the irradiation of the irradiation light to the target region; generating a reception spectrum, which is a relationship between a wavelength and the intensity of the measurement light for each position in the target region, based on the reception result of the measurement light; and calculating a transmittance or reflectance for each wavelength of a measurement object disposed in the measurement region based on the generated reception spectrum. In the step of calculating the transmittance or the reflectance, a first reference spectrum, which is the reception spectrum based on the measurement light generated from the measurement region when the measurement object does not exist, a second reference spectrum, which is the reception spectrum based on the measurement light generated from the non-measurement region, and a measurement spectrum, which is the reception spectrum based on the measurement light generated from the measurement region when the measurement object exists, are used to calculate the transmittance spectrum or reflectance spectrum of the measurement object.

[0019] Thus, by using a method of calculating the transmittance spectrum or reflectance spectrum of a measurement object based on a first reference spectrum based on the measurement light from the measurement region when the measurement object does not exist, a second reference spectrum based on the measurement light from the non-measurement region, and a measurement spectrum based on the measurement light from the measurement region when the measurement object exists, it is possible to calculate the transmittance spectrum or reflectance spectrum from the measurement spectrum while taking into account the influence of, for example, temporal changes in the irradiation light intensity and light reception sensitivity due to the time difference before and after disposing the measurement object in the measurement region, and variations in the irradiation light intensity and light reception sensitivity caused by differences in the irradiation positions between the measurement region and the non-measurement region. Therefore, it is possible to more accurately measure the transmittance spectrum or reflectance spectrum of the measurement object.

Advantages of the Invention

[0020] According to the present invention, the transmittance or reflectance of a measurement object can be measured more accurately.

Brief Description of the Drawings

[0021]

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Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their description will not be repeated. Also, at least a part of the embodiments described below may be arbitrarily combined.

[0023] <First Embodiment> [Optical Measurement Apparatus] FIG. 1 is a diagram showing an example of the configuration of the optical measurement apparatus according to the first embodiment of the present invention.

[0024] Referring to FIG. 1, the optical measurement apparatus 101 includes an irradiation optical system 10, a light receiving optical system 20, a processing device 30, a base member 4, and a support member 6. The base member 4 and the support member 6 fix the light receiving optical system 20. Note that the optical measurement apparatus 101 is not limited to a configuration including the base member 4 and the support member 6, and may be a configuration including other members for fixing the light receiving optical system 20 instead of or in addition to the base member 4 and the support member 6.

[0025] FIG. 2 is a diagram showing an example of the configuration of the optical measurement apparatus according to the first embodiment of the present invention. FIG. 2 shows a state in which the measurement object S, which is the measurement object of the optical measurement apparatus 101, is arranged.

[0026] Referring to FIG. 2, the optical measurement device 101 measures the transmittance of a measurement object S such as a film disposed in the measurement region R1.

[0027] For example, in the manufacturing line of the measurement object S, the optical measurement device 101 automatically measures the transmittance spectra at a plurality of measurement positions M on the measurement object S that is conveyed through the measurement region R1. That is, the optical measurement device 101 measures the transmittance spectra at a plurality of measurement positions M on the measurement object S in-line.

[0028] More specifically, the optical measurement device 101 calculates the transmittance for each wavelength at the measurement position M of the conveyed measurement object S, for example, by periodically performing transmittance measurement.

[0029] [Irradiation optical system] The irradiation optical system 10 irradiates a target region R including the measurement region R1 and a non-measurement region R2 that is a region different from the measurement region R1 with linearly polarized irradiation light including a plurality of wavelengths.

[0030] More specifically, the irradiation optical system 10 irradiates the target region R including the measurement region R1 which is a linear region and the non-measurement region R2 adjacent to the measurement region R1 at the longitudinal end of the measurement region R1 with irradiation light.

[0031] The irradiation optical system 10 includes a light source 11 and a line light guide 12.

[0032] The light source 11 emits light including a plurality of wavelengths. The spectrum of the light emitted by the light source 11 may be a continuous spectrum or a line spectrum. The wavelength of the light emitted by the light source 11 is set according to the range of wavelength information to be acquired from the measurement object S and the like. The light source 11 is, for example, a halogen lamp.

[0033] The line light guide 12 receives the light emitted from the light source 11, and emits the received light from a linear opening, thereby irradiating the target area R with the irradiation light in a straight line. On the light emission surface of the irradiation light in the line light guide 12, for example, a diffusion member or the like for suppressing uneven light quantity is arranged. The line light guide 12 is arranged directly below the surface on which the measurement object S is conveyed.

[0034] For example, when the irradiation optical system 10 performs an in-line measurement of the transmittance spectrum of the measurement object S, it irradiates the target area R with the irradiation light at the measurement timing, while stopping the irradiation of the irradiation light to the target area R at timings other than the measurement timing. Note that the irradiation optical system 10 may be configured to continuously irradiate the target area R with the irradiation light regardless of the measurement timing.

[0035] [Light receiving optical system] The light receiving optical system 20 receives the measurement light, which is the transmitted light generated from the target area R by the irradiation of the irradiation light to the target area R.

[0036] The light receiving optical system 20 includes an objective lens 21, an imaging spectrometer 22, and an imaging unit 23.

[0037] The light receiving optical system 20 is arranged at a position facing the line light guide 12 with the measurement object S interposed therebetween.

[0038] The light receiving optical system 20 receives, as the measurement light, the transmitted light that has passed through the target area R among the irradiation light emitted from the line light guide 12. Specifically, the light receiving optical system 20 receives the transmitted light of the measurement object S arranged in the measurement area R1 among the irradiation light emitted from the line light guide 12.

[0039] FIG. 3 is a diagram showing the configuration of the light receiving optical system in the optical measurement apparatus according to the first embodiment of the present invention.

[0040] Referring to FIG. 3, the imaging spectrometer 22 includes a slit 221, a first lens 222, a diffraction grating 223, and a second lens 224. The slit 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.

[0041] The imaging unit 23 is composed of an imaging device 231 having 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 a 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.

[0042] The objective lens 21 converges the measurement light from the target region R and guides it to the imaging spectrometer 22.

[0043] The slit 221 in the imaging spectrometer 22 shapes the beam cross-section of the measurement light incident on itself through the objective lens 21 into a predetermined shape. The length in the longitudinal direction of the slit 221 is set to a length corresponding to the length of the target region R, and the width in the short direction of the slit 221 is set according to the resolution of the diffraction grating 223 and the like.

[0044] The first lens 222 in the imaging spectrometer 22 converts the measurement light that has passed through the slit 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.

[0045] The diffraction grating 223 in the imaging spectrometer 22 performs wavelength expansion in a direction orthogonal to the longitudinal direction of the measurement light. More specifically, the diffraction grating 223 performs wavelength expansion, that is, spectroscopy, on the linear measurement light that has passed through the slit 221 in a direction orthogonal to the line direction.

[0046] In the imaging spectroscope 22, the second lens 224 forms an image of the measurement light wavelength-expanded by the diffraction grating 223 on the light-receiving surface of the imaging element 231 in the imaging unit 23 as a two-dimensional optical spectrum reflecting wavelength information and position information.

[0047] The imaging unit 23 transmits two-dimensional image data indicating the two-dimensional image P formed on the light-receiving surface of the imaging element 231 to the processing device 30 as a light-receiving result in the light-receiving optical system 20.

[0048] Hereinafter, the D1 direction in FIG. 3 in the two-dimensional image P is referred to as the "position direction", and the D2 direction orthogonal to the position direction is referred to as the "wavelength direction". Each point in the position direction corresponds to each measurement point X on the target region R. Each point in the wavelength direction corresponds to the wavelength of the measurement light from the corresponding measurement point X. Also, assume that the light-receiving surface of the imaging element 231 has m channels as the resolution in the wavelength direction and n channels as the resolution in the position direction. n is, for example, 1200.

[0049] [Processing device] FIG. 4 is a diagram showing the configuration of the processing device in the optical measurement device according to the first embodiment of the present invention.

[0050] Referring to FIG. 4, the processing device 30 includes a receiving unit 31, a calculating unit 32, and a storage unit 33.

[0051] The receiving unit 31 receives 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.

[0052] Based on the light-receiving result of the measurement light in the light-receiving optical system 20, the calculating unit 32 generates a light-receiving spectrum S(λ) that is the relationship between the wavelength λ and the intensity of the measurement light for each position in the target region R. Then, based on the generated light-receiving spectrum S(λ), the calculating unit 32 calculates the transmittance for each wavelength of the measurement object S arranged in the measurement region R1.

[0053] More specifically, the calculation unit 32 generates the received spectrum S(λ) based on the two-dimensional image data stored in the storage unit 33, and calculates the transmittance of the measurement object S for each wavelength λ based on the generated received spectrum S(λ).

[0054] The calculation unit 32 calculates the transmittance spectrum of the measurement object S based on the first reference spectrum St1(λ), which is the received spectrum S(λ) generated from the measurement light generated from the measurement region R1 when the measurement object S does not exist, the second reference spectrum St2(λ), which is the received spectrum S(λ) generated from the measurement light generated from the non-measurement region R2, and the measurement spectrum Stm(λ), which is the received spectrum S(λ) generated from the measurement light generated from the measurement region R1 when the measurement object S exists.

[0055] FIG. 5 is a diagram showing an example of the first reference spectrum generated by the optical measurement device according to the first embodiment of the present invention. In FIG. 5, the horizontal axis represents the wavelength, and the vertical axis represents the intensity. FIG. 5 shows the first reference spectrum St1(λ,X) based on the transmitted light generated from each of the n measurement points X on the measurement region R1.

[0056] Referring to FIG. 5, the calculation unit 32 generates a plurality of first reference spectra St1(λ,X) based on the measurement light generated from a plurality of positions, that is, the measurement points X, in the measurement region R1 when the measurement object S does not exist.

[0057] Then, the calculation unit 32 calculates the transmittance spectrum of the measurement object S based on the plurality of generated first reference spectra St1(λ,X), the second reference spectrum St2(λ), and the plurality of measurement spectra Stm(λ,X) respectively generated from the measurement light generated from the plurality of measurement points X.

[0058] For example, the calculation unit 32 calculates the transmittance distribution at the measurement position M of the measurement object S based on the first reference spectrum St1(λ,X), the second reference spectrum St2(λ), and the measurement spectrum Stm(λ,X).

[0059] More specifically, the calculation unit 32 uses the first reference spectrum St1(λ,X) and the second reference spectrum St2(λ) as reference data, and calculates the transmittance distribution at the measurement position M of the measurement object S based on the reference data and the measurement spectrum Stm(λ,X).

[0060] FIG. 6 is a diagram showing an example of a second reference spectrum generated by the optical measurement apparatus according to the first embodiment of the present invention. In FIG. 6, the horizontal axis represents wavelength, and the vertical axis represents intensity. FIG. 6 shows the second reference spectrum St2(λ) based on the transmitted light generated from the non-measurement region R2.

[0061] For example, the second reference spectrum St2(λ) is a spectrum generated in advance by the calculation unit 32 based on the measurement light generated from the non-measurement region R2 when the measurement object S does not exist in the measurement region R1.

[0062] For example, the first reference spectrum St1(λ,X) and the second reference spectrum St2(λ) are spectra generated by the calculation unit 32 based on the measurement light generated from the measurement region R1 and the measurement light generated from the non-measurement region R2, respectively, received by the light receiving optical system 20 at the same timing before the measurement object S exists in the measurement region R1.

[0063] More specifically, the first reference spectrum St1(λ,X) and the second reference spectrum St2(λ) are spectra respectively generated by the calculation unit 32 based on the transmitted light from the measurement region R1 and the transmitted light from the non-measurement region R2, which are received by the light receiving optical system 20 due to the irradiation of the irradiation optical system 10 on the target region R in a state where the measurement object S does not exist in the measurement region R1.

[0064] For example, before starting the in-line measurement of the transmittance distribution of the measurement object S and when the measurement object S is not arranged in the measurement region R1, the calculation unit 32 generates a first reference spectrum St1(λ,X) and a second reference spectrum St2(λ) based on the transmitted light from the measurement region R1 and the transmitted light from the non-measurement region R2 that are received by the light receiving optical system 20 at the same timing by the irradiation of the irradiation light to the target region R by the irradiation optical system 10.

[0065] Here, the received spectrum S(λ) generated by the calculation unit 32 is affected by variations in the irradiation light intensity according to the irradiation position of the irradiation light from the irradiation optical system 10, variations in the sensitivity at the light receiving position of the imaging element 231, and the like.

[0066] Therefore, referring to FIGS. 5 and 6, for example, the first reference spectrum St1(λ,x1) and the second reference spectrum St2(λ) are different from each other due to the effects such as the variations in the irradiation light intensity and the variations in the sensitivity.

[0067] In addition, the intensity of the irradiation light from the irradiation optical system 10 and the light receiving sensitivity in the light receiving optical system 20 vary over time, that is, temporally.

[0068] FIG. 7 is a diagram showing another example of the first reference spectrum generated by the optical measurement apparatus according to the first embodiment of the present invention. In FIG. 7, the horizontal axis represents the wavelength and the vertical axis represents the intensity. The broken line in FIG. 7 indicates the first reference spectrum St1(λ,x1) corresponding to the measurement point x1 in FIG. 5, and the solid line in FIG. 7 indicates the first reference spectrum St1(λ,x1) measured at a timing different from the measurement timing of the first reference spectrum St1(λ,x1) in FIG. 5.

[0069] FIG. 8 is a diagram showing another example of the second reference spectrum generated by the optical measurement apparatus according to the first embodiment of the present invention. In FIG. 8, the horizontal axis represents wavelength, and the vertical axis represents intensity. The broken line in FIG. 7 indicates the second reference spectrum St2(λ) in FIG. 6, and the solid line in FIG. 8 indicates the second reference spectrum St2(λ) measured at a timing different from the measurement timing of the second reference spectrum St2(λ) in FIG. 6.

[0070] Referring to FIG. 7, the intensity of the first reference spectrum St1(λ, x1) varies according to the measurement timing due to the influence of the temporal change in the intensity of the irradiation light and the temporal change in the light reception sensitivity described above.

[0071] Also, referring to FIG. 8, the intensity of the second reference spectrum St2(λ) varies according to the measurement timing due to the influence of the temporal change in the intensity of the irradiation light and the temporal change in the light reception sensitivity described above.

[0072] Therefore, for example, when measuring the transmittance distribution of the long measurement object S in-line over a long period while transporting the long measurement object S, in a method of calculating the transmittance spectrum based on the first reference spectrum St1(λ, X) and the second reference spectrum St2(λ) generated before starting the in-line measurement, and the measurement spectrum Stm(λ, X) generated during the in-line measurement, variations may occur in the calculated transmittance spectrum due to the influence of the temporal change in the intensity of the irradiation light and the temporal change in the light reception sensitivity described above.

[0073] Therefore, the calculation unit 32 calculates the transmittance spectrum of the measurement object S based further on the reference spectrum Str(λ), which is a light reception spectrum generated from the non-measurement region R2 when the measurement object S exists in the measurement region R1.

[0074] More specifically, the calculation unit 32 corrects the reference spectrum Str(λ) using the first reference spectrum St1(λ, X) and the second reference spectrum St2(λ), thereby generating a virtual reference spectrum Stv(λ, X) which is virtual reference data in the measurement region R1 taking into account the variations and fluctuations of the received spectrum S(λ). Then, the calculation unit 32 calculates the transmittance spectrum of the measurement object S based on the generated virtual reference spectrum Stv(λ, X) and the measurement spectrum Stm(λ, X).

[0075] The reference spectrum Str(λ) and the measurement spectrum Stm(λ, X) are spectra generated by the calculation unit 32 based on the measurement light generated from the non-measurement region R2 and the measurement light generated from the measurement region R1, which are received by the light receiving optical system 20 at the same timing when the measurement object S exists in the measurement region R1, respectively.

[0076] More specifically, the reference spectrum Str(λ) and the measurement spectrum Stm(λ, X) are spectra respectively generated by the calculation unit 32 based on the transmitted light from the non-measurement region R2 and the transmitted light from the measurement region R1, i.e., the measurement object S, which are received by the light receiving optical system 20 due to the irradiation of the irradiation light to the target region R by the irradiation optical system 10 in a state where the measurement object S exists in the measurement region R1.

[0077] For example, after starting the in-line measurement of the transmittance distribution of the measurement object S and when the measurement object S is disposed in the measurement region R1, the calculation unit 32 generates the reference spectrum Str(λ) and the measurement spectrum Stm(λ, X) based on the transmitted light from the non-measurement region R2 and the transmitted light from the measurement region R1, which are received by the light receiving optical system 20 at the same timing due to the irradiation of the irradiation light to the target region R by the irradiation optical system 10.

[0078] FIG. 9 is a diagram showing the intensity ratio between a first reference spectrum and a second reference spectrum generated by the optical measurement device according to the first embodiment of the present invention. In FIG. 9, the horizontal axis represents wavelength, and the vertical axis represents the intensity ratio.

[0079] For example, the storage unit 33 stores the intensity ratio Pt(λ, X), which is the ratio of the first reference spectrum St1(λ, t, X) to the second reference spectrum St2(λ, t) for each wavelength λ at each measurement point X, generated in advance at a certain time t (t = t0) before the start of the in-line measurement. The intensity ratio Pt(λ, X) is represented by the following equation (1).

Equation

[0080] When the calculation unit 32 generates the measurement spectrum Stm(λ, t, X) and the reference spectrum Str(λ, t) at a certain time t (t = t1) after the start of the in-line measurement, it acquires the intensity ratio Pt(λ, X) in the storage unit 33, and uses the virtual reference spectrum Stv(λ, t, X) represented by the following equation (2) to calculate the transmittance spectrum ST(λ, t, X) indicating the transmittance at a plurality of measurement points X of the measurement object S, which is represented by the following equation (3).

[0081]

Equation

Equation

[0082] FIG. 10 is a diagram showing a transmittance spectrum generated by the optical measurement device according to the first embodiment of the present invention. In FIG. 10, the horizontal axis represents wavelength, and the vertical axis represents transmittance. The solid line in FIG. 10 indicates the transmittance spectrum ST(λ, t, X) calculated based on the virtual reference spectrum Stv(λ, t, X) and the measurement spectrum Stm(λ, t, X), and the dashed line in FIG. 10 indicates the transmittance spectrum calculated based on the first reference spectrum St1(λ, t, X) and the measurement spectrum Stm(λ, t, X) as a comparative example.

[0083] Referring to FIG. 10, by using the virtual reference spectrum Stv(λ, t, X) instead of the first reference spectrum St1(λ, t, X), a transmittance spectrum ST(λ, t, X) different from the transmittance spectrum calculated when using the first reference spectrum St1(λ, t, X) is calculated.

[0084] For example, the calculation unit 32 calculates a film thickness distribution indicating the film thickness at each measurement point X of the measurement object S based on the calculated transmittance spectrum ST(λ, t, X). Alternatively, the calculation unit 32 calculates the hue of the measurement object S based on the calculated transmittance spectrum ST(λ, t, X).

[0085] [Operation flow] The optical measurement device according to the embodiment of the present invention includes a computer including a memory, and an arithmetic calculation unit such as a CPU in the computer reads and executes a program including some or all of the steps of the following flowchart and sequence from the memory. The program of this device can be installed from the outside. The program of this device is distributed in a state stored in a recording medium.

[0086] FIG. 11 is a flowchart defining an example of an operation procedure for calculating the transmittance spectrum of a measurement object in the optical measurement device according to the first embodiment of the present invention.

[0087] Referring to FIG. 11, first, before starting the in-line measurement of the transmittance distribution of the measurement object S, the optical measurement device 101 linearly irradiates the target region R including the measurement region R1 and the non-measurement region R2 with irradiation light including a plurality of wavelengths in a state where the measurement object S is not arranged in the measurement region R1 (step S102).

[0088] Next, the optical measurement device 101 receives the measurement light, that is, the transmitted light, generated from the target region R by the irradiation of the irradiation light on the target region R (step S104).

[0089] Next, the optical measurement device 101 generates a first reference spectrum St1(λ, t, X) and a second reference spectrum St2(λ, t) based on the received light result of the measurement light (step S106).

[0090] Next, the optical measurement device 101 calculates the intensity ratio Pt(λ, X) between the first reference spectrum St1(λ, t, X) and the second reference spectrum St2(λ, t), and stores the calculated intensity ratio Pt(λ, X) in the storage unit 33.

[0091] Next, after the start of the in-line measurement, the optical measurement device 101 waits for the measurement timing which is the timing at which the measurement should be performed (NO in step S110), and at the measurement timing (YES in step S110), linearly irradiates the target region R with the irradiation light. Specifically, the optical measurement device 101 linearly irradiates the measurement object S and the non-measurement region R2 with the irradiation light (step S112).

[0092] Next, the optical measurement device 101 receives the measurement light, that is, the transmitted light, generated from the target region R by the irradiation of the irradiation light on the target region R. Specifically, the optical measurement device 101 receives the transmitted light transmitted through the measurement object S and the transmitted light from the non-measurement region R2 (step S114).

[0093] Next, the optical measurement device 101 generates a reference spectrum Str(λ, t) and a measurement spectrum Stm(λ, t, X) based on the received light result of the measurement light (step S116).

[0094] Next, the optical measurement device 101 calculates the transmittance spectrum ST(λ,t,X) at the measurement position M of the measurement object S based on the virtual reference spectrum Stv(λ,t,X) calculated using the reference spectrum Str(λ,t) and the intensity ratio Pt(λ,X), and the measurement spectrum Stm(λ,t,X) (step S118).

[0095] Next, the optical measurement device 101 waits for the next measurement timing (NO in step S110).

[0096] Note that in the optical measurement device 101 according to the embodiment of the present invention, the irradiation optical system 10 is configured to irradiate the target region R including the measurement region R1 and the non-measurement region R2 adjacent to the measurement region R1 at one end in the longitudinal direction of the measurement region R1 with irradiation light, but is not limited thereto. The irradiation optical system 10 may be configured to irradiate the target region R including the measurement region R1, the non-measurement region R2a adjacent to the measurement region R1 at one end in the longitudinal direction of the measurement region R1, and the non-measurement region R2b adjacent to the measurement region R1 at the other end in the longitudinal direction of the measurement region R1 with irradiation light.

[0097] In this case, for example, the calculation unit 32 calculates the average value of the light reception spectrum based on the measurement light generated from the non-measurement region R2a and the light reception spectrum based on the measurement light generated from the non-measurement region R2b as the second reference spectrum St2(λ) or St2(λ,t). Also, for example, the calculation unit 32 calculates the average value of the light reception spectrum based on the measurement light generated from the non-measurement region R2a and the light reception spectrum based on the measurement light generated from the non-measurement region R2b when the measurement object S exists in the measurement region R1 as the reference spectrum Str(λ) or Str(λ,t).

[0098] In the optical measurement device 101 according to the embodiment of the present invention, the calculation unit 32 generates the second reference spectrum St2(λ) or St2(λ,t) based on the transmitted light from the non-measurement region R2 received by irradiating the target region R with the irradiation light in a state where the measurement object S is not disposed in the measurement region R1. However, the present invention is not limited to this. The calculation unit 32 may generate the second reference spectrum St2(λ) or St2(λ,t) based on the transmitted light from the non-measurement region R2 received by irradiating the target region R with the irradiation light in a state where the measurement object S is disposed in the measurement region R1. That is, the calculation unit 32 may be configured to generate the second reference spectrum St2(λ) or St2(λ,t) at a timing different from the timing of generating the reference spectrum Str(λ) or Str(λ,t), for example, after the start of the in-line measurement of the transmittance distribution of the measurement object S.

[0099] In the optical measurement device 101 according to the embodiment of the present invention, the calculation unit 32 generates the reference spectrum Str(λ) or Str(λ,t), and the measurement spectrum Stm(λ,X) or Stm(λ,t,X) based on the transmitted light from the non-measurement region R2 and the transmitted light from the measurement region R1 received at the same timing in the light reception optical system 20 by irradiating the target region R with the irradiation light from the irradiation optical system 10 in a state where the measurement object S is disposed in the measurement region R1. However, the present invention is not limited to this. The calculation unit 32 may be configured to generate the reference spectrum Str(λ) or Str(λ,t), and the measurement spectrum Stm(λ,X) or Stm(λ,t,X) based on the transmitted light received by the light reception optical system 20 at different timings.

[0100] Also, in the optical measurement device 101 according to the embodiment of the present invention, the calculation unit 32 generates the first reference spectrum St1(λ,X) or St1(λ,t,X), and the second reference spectrum St2(λ) or St2(λ,t) based on the transmitted light from the measurement region R1 and the transmitted light from the non-measurement region R2 that are received by the light receiving optical system 20 at the same timing when the measurement object S is not arranged in the measurement region R1 by the irradiation of the irradiation optical system 10 to the target region R. However, the present invention is not limited to this. The calculation unit 32 may be configured to generate the first reference spectrum St1(λ,X) or St1(λ,t,X), and the second reference spectrum St2(λ) or St2(λ,t) based on the transmitted light received by the light receiving optical system 20 at different timings in a state where the measurement object S is not arranged in the measurement region R1.

[0101] Also, in the optical measurement device 101 according to the embodiment of the present invention, the calculation unit 32 calculates the transmittance spectrum ST(λ,X) or ST(λ,t,X) of the measurement object S at a plurality of measurement points X in the measurement region R1 based on a plurality of first reference spectra St1(λ,X) or St1(λ,t,X), a plurality of second reference spectra St2(λ) or St2(λ,t), and a plurality of measurement spectra Stm(λ,X) or Stm(λ,t,X) respectively generated based on the measurement light generated from the plurality of measurement points X in the measurement region R1. However, the present invention is not limited to this. The calculation unit 32 may be configured to calculate the transmittance spectrum ST(λ,xj) or ST(λ,t,xj) of the measurement object S at the position xj based on the first reference spectrum St1(λ,xj) or St1(λ,t,xj), the second reference spectrum St2(λ) or St2(λ,t), and the measurement spectrum Stm(λ,xj) or Stm(λ,t,xj) generated based on the measurement light generated from one position xj in the measurement region R1.

[0102] Next, other embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their description will not be repeated.

[0103] <Second Embodiment> This embodiment relates to an optical measurement device 102 that receives reflected light generated from the target region R by irradiating the target region R with irradiation light, and generates a reflectance spectrum for each wavelength of the measurement object S based on the light reception result of the reflected light, compared with the optical measurement device 101 according to the first embodiment. It is the same as the optical measurement device 101 according to the first embodiment except for the content described below.

[0104] [Optical Measurement Device] FIG. 12 is a diagram showing an example of the configuration of an optical measurement device according to the second embodiment of the present invention.

[0105] Referring to FIG. 12, the optical measurement device 102 includes an irradiation optical system 10, a light reception optical system 20, a processing device 30, a base member 4, and a support member 6. The base member 4 and the support member 6 fix the light reception optical system 20. Note that the optical measurement device 102 is not limited to a configuration including the base member 4 and the support member 6, and may be a configuration including other members for fixing the light reception optical system 20 instead of or in addition to the base member 4 and the support member 6.

[0106] FIG. 13 is a diagram showing an example of the configuration of an optical measurement device according to the second embodiment of the present invention. FIG. 13 shows a state in which a reflector 41 is arranged in the measurement region R1 and a reflector 40 is arranged in the non-measurement region R2.

[0107] The reflectors 40 and 41 are, for example, glass plates, Si plates, or aluminum mirrors. For example, the reflectance of the reflector 40 and the reflectance of the reflector 41 are substantially the same. The reflectors 40 and 41 may be an integrated single reflector.

[0108] FIG. 14 is a diagram showing an example of the configuration of an optical measurement apparatus according to a second embodiment of the present invention. FIG. 14 shows a state in which a measurement object S, which is a measurement target of the optical measurement apparatus 102, is arranged.

[0109] Referring to FIG. 14, the optical measurement apparatus 102 measures the reflectance spectrum of the measurement object S arranged in the measurement region R1 in a state where the reflector 40 is arranged in the non-measurement region R2.

[0110] For example, the optical measurement apparatus 102 automatically measures the reflectance spectra at a plurality of measurement positions M on the measurement object S that is conveyed through the measurement region R1 in the manufacturing line of the measurement object S. That is, the optical measurement apparatus 102 measures the reflectance spectra at a plurality of measurement positions M on the measurement object S in-line.

[0111] More specifically, the optical measurement apparatus 102 calculates the reflectance for each wavelength at the measurement position M of the conveyed measurement object S, for example, by performing reflectance measurement periodically.

[0112] [Irradiation optical system] The irradiation optical system 10 irradiates a target region R including the measurement region R1 and a non-measurement region R2, which is a region different from the measurement region R1, with linearly polarized irradiation light including a plurality of wavelengths.

[0113] 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 arranged in the measurement region R1 is θ.

[0114] [Light receiving optical system] The light receiving optical system 20 receives measurement light, which is reflected light generated from the target region R by the irradiation of the irradiation light on the target region R.

[0115] The light receiving optical system 20 is arranged on the same side as the line light guide 12 with respect to the measurement object S and at a position where it can receive the reflected light with a reflection angle of θ in the measurement object S.

[0116] The light-receiving optical system 20 receives, as measurement light, the reflected light that is reflected in the target area R among the irradiation light emitted from the line light guide 12. Specifically, the light-receiving optical system 20 receives the reflected light of the measurement object S disposed in the measurement area R1 among the irradiation light emitted from the line light guide 12.

[0117] [Processing device] The calculation unit 32 in the processing device 30 generates a light-receiving spectrum S(λ), which is the relationship between the wavelength λ and the intensity of the measurement light, for each position in the target area R, based on the light-receiving result of the measurement light in the light-receiving optical system 20. Then, the calculation unit 32 calculates the reflectance for each wavelength of the measurement object S disposed in the measurement area R1 based on the generated light-receiving spectrum S(λ).

[0118] More specifically, the calculation unit 32 generates the light-receiving spectrum S(λ) based on the two-dimensional image data stored in the storage unit 33, and calculates the reflectance for each wavelength λ of the measurement object S based on the generated light-receiving spectrum S(λ).

[0119] As shown in FIG. 13, the calculation unit 32 calculates the reflectance spectrum of the measurement object S based on a first reference spectrum Sr1(λ), which is a light-receiving spectrum S(λ) generated from the measurement light generated from the measurement area R1 when the measurement object S does not exist and the reflector 41 exists, a second reference spectrum Sr2(λ), which is a light-receiving spectrum S(λ) generated from the measurement light generated from the non-measurement area R2 when the reflector 40 exists, and a measurement spectrum Srm(λ), which is a light-receiving spectrum S(λ) generated from the measurement light generated from the measurement area R1 when the measurement object S exists, as shown in FIG. 14.

[0120] For example, the calculation unit 32 generates a plurality of first reference spectra Sr1(λ,X) based on the measurement light generated from a plurality of measurement points X in the measurement area R1 when the measurement object S does not exist and the reflector 41 exists.

[0121] Then, the calculation unit 32 calculates the reflectance spectrum of the measurement object S based on the plurality of generated first reference spectra Sr1(λ, X), the second reference spectrum Sr2(λ), and the plurality of measurement spectra Srm(λ, X) generated from the measurement light generated at the plurality of measurement points X.

[0122] For example, the calculation unit 32 calculates the reflectance distribution at the measurement position M of the measurement object S based on the first reference spectrum Sr1(λ, X), the second reference spectrum Sr2(λ), and the measurement spectrum Srm(λ, X).

[0123] For example, the second reference spectrum Sr2(λ) is a spectrum generated in advance by the calculation unit 32 based on the measurement light generated from the non-measurement region R2 when the measurement object S does not exist in the measurement region R1.

[0124] The first reference spectrum Sr1(λ, X) and the second reference spectrum Sr2(λ) are spectra generated by the calculation unit 32 based on the measurement light generated from the measurement region R1 and the measurement light generated from the non-measurement region R2, respectively, which are received by the light receiving optical system 20 at the same timing before the measurement object S exists in the measurement region R1.

[0125] More specifically, as shown in FIG. 13, the first reference spectrum Sr1(λ, X) and the second reference spectrum Sr2(λ) are the reflected light from the measurement region R1 and the reflected light from the non-measurement region R2 received by the light receiving optical system 20 due to the irradiation of the irradiation light to the target region R by the irradiation optical system 10 in a state where the measurement object S does not exist in the measurement region R1 and the reflecting plate 41 and the reflecting plate 40 exist in the measurement region R1 and the non-measurement region R2, respectively, and are spectra generated by the calculation unit 32.

[0126] For example, before starting the in-line measurement of the reflectance distribution of the measurement object S and with the reflectors 40 and 41 arranged in the target region R, the first reference spectrum Sr1(λ, X) and the second reference spectrum Sr2(λ) are respectively generated based on the reflected light from the reflector 41 and the reflector 40, which is received by the light receiving optical system 20 due to the irradiation of the irradiation light to the target region R by the irradiation optical system 10.

[0127] The calculation unit 32 calculates the reflectance spectrum of the measurement object S based on the reference spectrum Srr(λ), which is the light receiving spectrum generated from the measurement light generated from the non-measurement region R2 when the measurement object S exists in the measurement region R1.

[0128] The reference spectrum Srr(λ) and the measurement spectrum Srm(λ, X) are, for example, spectra generated by the calculation unit 32 based on the measurement light generated from the non-measurement region R2 and the measurement light generated from the measurement region R1, which are received by the light receiving optical system 20 at the same timing when the measurement object S exists in the measurement region R1.

[0129] More specifically, as shown in FIG. 14, the reference spectrum Srr(λ) and the measurement spectrum Srm(λ, X) are spectra respectively generated by the calculation unit 32 based on the reflected light from the non-measurement region R2, that is, the reflector 40, and the reflected light from the measurement region R1, that is, the measurement object S, which are received by the light receiving optical system 20 due to the irradiation of the irradiation light to the target region R by the irradiation optical system 10 in a state where the measurement object S exists in the measurement region R1.

[0130] For example, after starting the in-line measurement of the reflectance distribution of the measurement object S and with the measurement object S arranged in the measurement region R1 instead of the reflector 41, the reference spectrum Srr(λ) and the measurement spectrum Srm(λ, X) are generated based on the reflected light from the non-measurement region R2 and the reflected light from the measurement region R1, which are received by the light receiving optical system 20 at the same timing due to the irradiation of the irradiation light to the target region R by the irradiation optical system 10.

[0131] For example, the memory unit 33 stores an intensity ratio Pr(λ, X), which is the ratio of a first reference spectrum Sr1(λ, t, X) to a second reference spectrum Sr2(λ, t) for each wavelength λ at each measurement point X, pre-generated at a certain time t (t = t0) before the start of the in-line measurement. The intensity ratio Pr(λ, X) is represented by the following formula (4). [Number]

[0132] When the calculation unit 32 generates a measurement spectrum Srm(λ, t, X) and a reference spectrum Srr(λ, t) at a certain time t (t = t1) after the start of the in-line measurement, it acquires the intensity ratio Pr(λ, X) in the memory unit 33, and uses a virtual reference spectrum Srv(λ, t, X) represented by the following formula (5) to calculate a reflectance spectrum SR(λ, t, X) indicating the reflectance at a plurality of measurement points X of the measurement object S, represented by the following formula (6).

[0133] [Number] [Number]

[0134] For example, the calculation unit 32 calculates a film thickness distribution indicating the film thickness at each measurement point X of the measurement object S based on the calculated reflectance spectrum SR(λ, t, X). Alternatively, the calculation unit 32 calculates the hue of the measurement object S based on the calculated reflectance spectrum SR(λ, t, X).

[0135] Note that in the optical measurement device 102 according to the second embodiment of the present invention, the line light guide 12 of the irradiation optical system 10 is arranged such that the incident angle of the irradiation light to the measurement object S arranged in the measurement region R1 is θ, but the present invention is not limited to this configuration.

[0136] Further, in the optical measurement device 102 according to the second embodiment of the present invention, although the light receiving optical system 20 is arranged on the same side as the line light guide 12 with respect to the measurement object S and at a position where it can receive the reflected light with a reflection angle of θ in the measurement object S, the present invention is not limited to this.

[0137] FIG. 15 is a diagram showing an example of the configuration of an optical measurement device according to a modified example of the second embodiment of the present invention.

[0138] Referring to FIG. 15, the line light guide 12 has a half mirror 121. The line light guide 12 irradiates the target area R with the irradiation light reflected by the half mirror 121. In this case, for example, the line light guide 12 is arranged directly above the surface on which the measurement object S is conveyed so that the incident angle of the irradiation light to the measurement object S arranged in the measurement area R1 becomes 0°. That is, the irradiation optical system 10 of the optical measurement device 102 is coaxial epi-illumination.

[0139] The light receiving optical system 20 receives the reflected light generated from the target area R due to the irradiation of the irradiation light to the target area R through the half mirror 121. In this case, for example, the light receiving optical system 20 is arranged at a position where it can receive the reflected light with a reflection angle of 0° in the measurement object S, that is, at a position facing the target area R with the line light guide 12 interposed therebetween.

[0140] The above embodiments should be considered as illustrative in all respects and not restrictive. The scope of the present invention is shown 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.

Explanation of Reference Numerals

[0141] 10 Irradiation optical system 20 Light receiving optical system 30 Processing device 31 Receiver 32 Calculation unit 33 Storage unit 101, 102 Optical measurement device

Claims

1. An irradiation optical system that linearly irradiates an object region including a measurement region and a non-measurement region that is a region different from the measurement region with irradiation light including a plurality of wavelengths; A light receiving optical system that receives measurement light that is transmitted light or reflected light generated from the object region by the irradiation of the irradiation light on the object region; Based on the light receiving result of the measurement light in the light receiving optical system, a light receiving spectrum that is the relationship between the wavelength and the intensity of the measurement light for each position in the object region is generated, and based on the generated light receiving spectrum, a calculation unit that calculates the transmittance or reflectance for each wavelength of the measurement object disposed in the measurement region; The calculation unit calculates the transmittance spectrum or reflectance spectrum of the measurement object by performing arithmetic processing using a first reference spectrum that is the light receiving spectrum generated from the measurement region when the measurement object does not exist, a second reference spectrum that is the light receiving spectrum generated from the non-measurement region, and a measurement spectrum that is the light receiving spectrum generated from the measurement region when the measurement object exists. The second reference spectrum is a spectrum generated based on the measurement light generated from the non-measurement region when the measurement object does not exist in the measurement region, an optical measurement device.

2. In the arithmetic processing, the calculation unit uses the first reference spectrum and the second reference spectrum as reference data, and calculates the transmittance spectrum or the reflectance spectrum of the measurement object based on the reference data and the measurement spectrum. The optical measurement device according to claim 1.

3. Irradiating a target area including a measurement area and a non-measurement area that is a different area from the measurement area with linearly polarized irradiation light including a plurality of wavelengths; Receiving measurement light that is transmitted light or reflected light generated from the object region by the irradiation of the irradiation light on the object region; Based on the light receiving result of the measurement light, generating a light receiving spectrum that is the relationship between the wavelength and the intensity of the measurement light for each position in the object region, and based on the generated light receiving spectrum, calculating the transmittance or reflectance for each wavelength of the measurement object disposed in the measurement region. In the step of calculating the transmittance or the reflectance, by performing arithmetic processing using a first reference spectrum which is the received light spectrum based on the measurement light generated from the measurement region when the object to be measured does not exist, a second reference spectrum which is the received light spectrum based on the measurement light generated from the non-measurement region, and a measurement spectrum which is the received light spectrum based on the measurement light generated from the measurement region when the object to be measured exists, a transmittance spectrum or a reflectance spectrum of the object to be measured is calculated. The second reference spectrum is a spectrum generated based on the measurement light generated from the non-measurement region when the object to be measured does not exist in the measurement region, optical measurement method.

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