Parameter estimation method, parameter estimation system, and parameter estimation program

Abstract

To estimate optical parameters of various materials with high accuracy.SOLUTION: A parameter calculation method includes a computer: measuring the total transmittance, rectilinear propagation transmittance, and reflectance of a support layer of a prescribed thickness by optical measurement of a support layer composed only of a support material by using light of a prescribed wavelength; estimating an optical parameter including the absorption coefficient, scattering coefficient, and scattering anisotropy parameter of the support material on the basis of the total transmittance, rectilinear propagation transmittance, and reflectance of the support layer; measuring the total transmittance, rectilinear propagation transmittance, and reflectance of a composite layer of each of a plurality of thicknesses by optical measurement of a composite layer of a plurality of thicknesses of a multilayer material with a material of interest added to the support layer using light with a prescribed wavelength; estimating the optical parameter of the multilayer material on the basis of the total transmittance, rectilinear propagation transmittance, and reflectance of the composite layer; and estimating the optical parameter of the material of interest on the basis of the optical parameter of the support material and the optical parameter of the multilayer material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a parameter estimation method, a parameter estimation system, and a parameter estimation program. [Background technology]

[0002] Conventionally, there has been known a technique for estimating the optical parameters of a material based on the transmitted light characteristics and reflected light characteristics of the material.

[0003] For example, the light scattering property measurement method described in Patent Document 1 is characterized in that the transmitted light properties and reflected light properties of a light scatterer to be measured are actually measured, parameter values ​​used in the Monte Carlo method for light scattering are generated by a computer, and Monte Carlo method calculations are performed on the light scatterer while changing the parameter values, parameter values ​​that match the calculation results and the actually measured data are found, and the parameter values ​​are used as characteristic data of the light scatterer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-85940 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the light scattering property measurement method described in Patent Document 1 is based on the premise that the transmitted light properties and reflected light properties of the object to be measured can be actually measured. Therefore, it does not take into consideration cases where the transmitted light properties and reflected light properties of the object to be measured cannot be actually measured. Furthermore, this light scattering property measurement method determines the parameter values ​​by setting the light absorption coefficient of the light scatterer to 0. However, in the case of an object to be measured in which light absorption cannot be ignored, the light absorption coefficient must also be taken into consideration when comparing the obtained parameter values ​​with actual measurement data. As the number of parameters to be searched increases, the accuracy of the obtained parameter values ​​may decrease.

[0006] Furthermore, the light scattering property measurement method described in Patent Document 1 does not take into consideration changes in the thickness of the object being measured, and sufficient consideration has not been given to whether the accuracy of the optical parameters is guaranteed even for objects of different thicknesses.

[0007] Therefore, an object of the present invention is to estimate the optical parameters of various materials with high accuracy. [Means for solving the problem]

[0008] A parameter estimation method according to one embodiment of the present invention includes: a support measurement value acquisition step in which a computer acquires support measurement values, which are at least one of the total transmittance, rectilinear transmittance, and reflectance, at a predetermined film thickness of a support layer made only of a support material, by optical measurement using light of a predetermined wavelength; a support estimation step in which, based on the support measurement values ​​acquired in the support measurement value acquisition step, optical parameters including an absorption coefficient, a scattering coefficient, and a scattering anisotropy parameter of the support material; a composite layer measurement value acquisition step in which, in a plurality of composite layers formed by stacking layers made of a target material of different film thicknesses on the support layer, composite layer measurement values, which are at least one of the total transmittance, rectilinear transmittance, and reflectance for each of a plurality of composite layers made of a target material and having different film thicknesses, by optical measurement using light of a predetermined wavelength; and a target material estimation step in which, based on the composite layer measurement values ​​acquired in the composite layer measurement value acquisition step and the optical parameters of the support material estimated in the support estimation step, the target material is estimated. [Effects of the Invention]

[0009] According to the present invention, the optical parameters of various materials can be estimated with high accuracy. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an overview of processing in a parameter estimation system 100 according to an embodiment of the present invention. [Figure 2] 1 is a diagram showing the configuration of a parameter estimation system 100 according to an embodiment of the present invention. [Figure 3A] 10A and 10B are diagrams illustrating an example of a measurement method in the measurement device 200. [Figure 3B] 10A and 10B are diagrams illustrating an example of a measurement method in the measurement device 200. [Figure 4] FIG. 1 is a diagram illustrating an overview of the reverse Monte Carlo method. [Figure 5A] FIG. 10 is a conceptual diagram showing the relationship between film thickness and total transmittance at different wavelengths. [Figure 5B] FIG. 10 is a conceptual diagram showing the relationship between film thickness and rectilinear transmittance at different wavelengths. [Figure 5C] FIG. 10 is a conceptual diagram showing the relationship between film thickness and reflectance at different wavelengths. [Figure 6] FIG. 6 is a diagram illustrating an example of the hardware configuration of a computer 600. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a diagram showing an overview of processing in a parameter estimation system 100 according to one embodiment of the present invention.

[0012] The parameter estimation system 100 is an information processing system realized by a parameter estimation program. The parameter estimation system 100 estimates the optical parameters of a target material based on the optical parameters of a support material estimated based on measurements of a support layer consisting of only the support material, and on measurements of a composite layer formed by laminating a layer of the target material on the support layer.

[0013] First, the parameter estimation system 100 acquires support measurement values, which are at least one of total transmittance, rectilinear transmittance, and reflectance at a predetermined film thickness of a support layer made only of the support material, by optical measurement using light of a predetermined wavelength (S101).The parameter estimation system 100 estimates optical parameters, including the absorption coefficient, scattering coefficient, and scattering anisotropy parameter of the support material, using the reverse Monte Carlo method based on the support measurement values, which are at least one of total transmittance, rectilinear transmittance, and reflectance at a predetermined film thickness of the support layer (S102).

[0014] Next, the parameter estimation system 100 acquires composite layer measurement values, which are at least one of the total transmittance, rectilinear transmittance, and reflectance, for each of a plurality of composite layers formed by laminating layers of the target material with different thicknesses on a support layer, by optical measurement using light of a predetermined wavelength (S103).The parameter estimation system 100 estimates the optical parameters of the target material using the reverse Monte Carlo method based on the composite layer measurement values ​​acquired in S103 and the optical parameters of the support material estimated in S102.

[0015] 2 is a diagram showing the configuration of a parameter estimation system 100 according to one embodiment of the present invention. The parameter estimation system 100 may be communicably connected to a measurement device 200 via a network such as the Internet. Details of the parameter estimation system 100 will be described later.

[0016] The measuring device 200 acquires support measurement values, which are at least one of total transmittance, rectilinear transmittance, and reflectance at a predetermined film thickness of a support layer consisting only of the support material, by optical measurement using light of a predetermined wavelength, and outputs support measurement value information regarding the support measurement values ​​to the parameter estimation system 100.

[0017] Furthermore, the measuring device 200 acquires composite layer measurement values, which are at least one of the total transmittance, rectilinear transmittance, and reflectance, for each of a plurality of composite layers formed by laminating layers of the target material with different thicknesses on a support layer, by optical measurement using light of a predetermined wavelength, and outputs composite layer measurement value information regarding the composite layer measurement values ​​to the parameter estimation system 100.

[0018] The measurement method using the measurement device 200 will be described later.

[0019] 2, only one measuring device 200 is shown, but there may be a plurality of measuring devices 200. Furthermore, the user may input the measurement value information acquired by the measuring device 200 (i.e., for example, support measurement value information and composite layer measurement value information) to the parameter estimation system 100.

[0020] The parameter estimation system 100 includes a storage unit 110, a support measurement acquisition unit 120, a support estimation unit 130, a composite layer measurement acquisition unit 140, and a target material estimation unit 150. Each unit shown in Fig. 2 can be realized, for example, by using a storage area or by a processor executing a program stored in the storage area.

[0021] The storage unit 110 stores information processed in the parameter estimation system 100. The storage unit 110 can store, for example, support measurement information, support estimation result information, composite layer measurement information, and target material estimation result information, which will be described later.

[0022] The support measurement value acquisition unit 120 acquires support measurement values, which are at least one of total transmittance, rectilinear transmittance, and reflectance at a predetermined film thickness of a support layer consisting only of the support material, by optical measurement using light of a predetermined wavelength, and stores support measurement value information regarding the support measurement values ​​in the memory unit 110.

[0023] The support measurement value acquiring section 120 may acquire support measurement value information relating to support measurement values ​​measured by the measurement device 200. The support measurement value acquiring section 120 may acquire the support measurement value information from the measurement device 200.

[0024] The predetermined wavelength may be one wavelength or multiple wavelengths. For example, it may be multiple wavelengths in the ultraviolet-visible region. When optical measurement is performed at multiple wavelengths, the support measurement value information may include support measurement value information for each of the multiple wavelengths, or may include only support measurement value information for the wavelength used to estimate the optical parameters.

[0025] The support material is not particularly limited as long as it has sufficient optical transparency at the wavelength at which optical measurement is performed and is self-supporting. For example, it may be a glass substrate, a polymer substrate, or a polyester film such as a PET (polyethylene terephthalate) film.

[0026] 3A and 3B are diagrams showing an example of a measurement method in the measurement device 200. FIG.

[0027] FIG. 3A shows an example of a method for measuring total transmittance and rectilinear transmittance in the measuring device 200. In FIG.

[0028] In the measurement method using the measurement device 200 shown in FIG. 3A, light emitted from a light source 310 passes through a material 320 (a support layer or a composite layer), and a detector 330 detects straight transmitted light 340 (T s ) and diffuse transmitted light 350 (T d ) including the total transmitted light (T t ) is detected. The measuring device 200 measures the total transmittance based on the direct transmitted light 340 and the diffuse transmitted light 350 detected by the detector 330, and measures the direct transmittance based on the direct transmitted light 340 detected by the detector 330.

[0029] FIG. 3B shows an example of a method for measuring reflectance in measurement device 200.

[0030] In the measurement method in the measurement device 200 shown in FIG. 3B, light emitted from a light source 310 is reflected by a material 320 (support layer or composite layer), and reflected light 360 (R t ) is detected. The measurement device 200 measures the reflectance based on the reflected light 360 detected by the detector 330.

[0031] The support estimation unit 130 estimates optical parameters including the absorption coefficient, scattering coefficient, and scattering anisotropy parameter of the support material based on the support measurement values, which are at least one of the total transmittance, rectilinear transmittance, and reflectance at a specified film thickness of the support layer, and stores support estimation result information related to the estimated results in the memory unit 110.

[0032] The support estimation unit 130 can estimate the optical parameters of the support material based on at least one of the support measurement values ​​of the total transmittance, rectilinear transmittance, and reflectance at a specified film thickness of the support layer, for example, using the reverse Monte Carlo method.

[0033] Specifically, the support estimation unit 130 can estimate the optical parameters of the support material by searching for optical parameters of the support material that minimize an evaluation function that evaluates the error between a support measurement value, which is at least one of total transmittance, rectilinear transmittance, and reflectance at a predetermined film thickness of the support layer, and a support calculation value, which is at least one of total transmittance, rectilinear transmittance, and reflectance calculated based on the generated optical parameters of the support material. The optical parameters can be generated by comprehensive generation or random generation. The optical parameters can be searched by evaluating all generated parameters or by evaluating only a portion of parameters generated using a Bayesian optimization method.

[0034] Here, the predetermined thickness of the support layer may be one thickness or multiple thicknesses. The support material has sufficient optical transparency at a predetermined wavelength and is less affected by absorption or scattering, so the influence of the support material on the total transmittance, rectilinear transmittance, and reflectance of the composite layer is small. Therefore, even if the optical parameters of the support material are estimated based on measurements of only one thickness of the support layer, the target material estimation unit 150 (described later) can estimate the optical parameters of the target material with high accuracy.

[0035] The total transmittance, rectilinear transmittance, and reflectance of a material depend on the optical parameters of the material. That is, the total transmittance, rectilinear transmittance, and reflectance of the material can be calculated based on the optical parameters of the material and other parameters (e.g., the position of the light source, the angle of the irradiated light, the film thickness, the refractive index of the material, etc.). Specific calculation methods will be described later.

[0036] Therefore, the support estimation unit 130 generates optical parameters and, based on the generated optical parameters, calculates a calculated support value, which is at least one of the total transmittance, rectilinear transmittance, and reflectance at a predetermined film thickness of the support layer. The support estimation unit 130 compares the calculated support value with the support measurement value indicated by the support measurement value information. The support estimation unit 130 repeats the generation of optical parameters, calculation of the calculated support value, and comparison with the support measurement value. This repetition may be performed a number of times set by an administrator of the parameter estimation system 100, or may end when the value of an evaluation function, which will be described later, becomes equal to or less than a predetermined value.

[0037] The support estimation unit 130 then estimates the optical parameters that most accurately reproduce the support measurement values ​​as the optical parameters of the support material. At this time, the support estimation unit 130 may use, for example, an evaluation function that evaluates the error between the support calculation values ​​and the support measurement values. The evaluation function may be, for example, the sum of squares of the errors between each calculated value (calculated values ​​of total transmittance, rectilinear transmittance, and reflectance) and each measured value (measured values ​​of total transmittance, rectilinear transmittance, and reflectance), or may be the square root of the sum of squares.

[0038] In this way, the support estimation unit 130 can generate optical parameters and search for appropriate optical parameters by comparing the support calculation values ​​of total transmittance, rectilinear transmittance, and reflectance based on the generated optical parameters with the support measurement values.

[0039] FIG. 4 is a diagram illustrating an outline of a method for estimating optical parameters of a support material using the reverse Monte Carlo method, performed by the support estimation unit 130. First, the support estimation unit 130 generates optical parameters (S401). Next, the support estimation unit 130 calculates support calculation values ​​for the total transmittance, rectilinear transmittance, and reflectance at a predetermined film thickness of the support layer based on the generated optical parameters (S402). The support estimation unit 130 compares the support calculation values ​​with the support measurement values ​​indicated by the support measurement value information based on the evaluation function (S403). The process returns to S401, generates other optical parameters, and repeats the steps up to S403. At a predetermined timing, the support estimation unit 130 ends the repetition, and the optical parameters of the support material are determined (S404). Note that the target material estimation unit 150, described later, can also estimate the optical parameters of the target material using a similar method.

[0040] Next, an example of a method for calculating the total transmittance, rectilinear transmittance, and reflectance in S402 will be described in detail. The scattering coefficient is μ s , the extinction coefficient is μ a Considering the case where one photon is incident on the surface of a material with a scattering anisotropy parameter g, the mean free path L of the photon is expressed by the following equation (1):

[0041]

number

[0042] Here, r1 is a random number between 0 and 1.

[0043] Assuming that a photon that has traveled a distance L is simultaneously scattered and absorbed, the photon's light intensity is attenuated by a weight W shown in equation (2), and the photon is scattered in the direction of the zenith angle θ shown in equation (3) relative to the direction of travel of the photon. Note that the photon is scattered isotropically in the azimuthal angle direction.

[0044]

number

[0045]

number

[0046] Here, f(θ) represents the cumulative distribution function of the scattering phase function p(θ), and r2 is a random number between 0 and 1. An example of the phase function is the Henyey-Greenstein phase function shown in equation (4).

[0047]

number

[0048] In equation (4), when g≠0, cos θ is expressed by equation (5).

[0049]

number

[0050] Using these equations, the propagation path of a photon and the attenuation of its light intensity along that path can be simulated from the scattering coefficient μs, the absorption coefficient μa, and the scattering anisotropy parameter g. When the light intensity of a photon becomes sufficiently small (for example, when it becomes less than 1 / 10,000 of the light intensity at the time of incidence), the photon can be considered to have disappeared. When a photon is emitted from the incident surface of a material, the photon is considered to have been reflected, and when a photon is emitted from the surface opposite the incident surface of the material (i.e., when the photon has propagated a distance of more than the film thickness d of the material in the film thickness direction), the photon is considered to have been transmitted, and the light intensity of the emitted photon is recorded.

[0051] Furthermore, when a photon reaches a material interface, for example, a support layer-air interface or a support layer-target material layer interface in a composite layer, the photon may be considered to have been reflected or transmitted based on the probability calculated using Fresnel's equations.

[0052] By performing such calculations for multiple photons, the total transmittance, rectilinear transmittance, and reflectance of the material can be calculated as the light intensity of transmitted photons, rectilinearly transmitted photons, and reflected photons relative to the light intensity of the incident photon.

[0053] The value range for generating the optical parameters may be set by the administrator of the parameter estimation system 100 for each optical parameter.

[0054] Furthermore, when estimating the optical parameters of the support material, the support estimation unit 130 may use the actual measured value of the refractive index of the support material, or may simultaneously estimate the refractive index of the support material. The refractive index may be measured using, for example, a prism coupler, or the refractive index at a predetermined wavelength may be estimated using the Cauchy dispersion formula or the Sellmeier dispersion formula based on the refractive index values ​​at each wavelength measured using the prism coupler. When estimating the refractive index of the support material, the refractive index may be simultaneously generated when generating the optical parameters, and the refractive index that can most accurately reproduce the measured support values ​​may be estimated as the refractive index of the support material.

[0055] The composite layer measurement value acquisition unit 140 acquires composite layer measurement values, which are at least one of the total transmittance, rectilinear transmittance, and reflectance, for each of a plurality of composite layers formed by laminating layers made of a target material with different thicknesses on a support layer, by optical measurement using light of a predetermined wavelength, and stores composite layer measurement value information regarding the composite layer measurement values ​​in the memory unit 110.

[0056] Here, the target material may be, for example, a composite material containing multiple materials, or may be, for example, a non-self-supporting film material for which it is difficult to measure the total transmittance, rectilinear transmittance, and reflectance of a target material layer consisting only of the target material. The target material may be a photosensitive resin composition, for example, a solder resist or a photosensitive interlayer insulating material.

[0057] In this regard, when the target material is a composite material (e.g., solder resist), it is extremely difficult to individually measure the optical parameters of each material contained in the composite material, making it difficult to calculate the optical parameters of the target material based on the optical parameters of each material. Furthermore, when the target material is a non-self-supporting film material (e.g., a thin film of solder resist), it is difficult to obtain a self-supporting film of the target material layer consisting only of the target material, making it difficult to measure the total transmittance, rectilinear transmittance, and reflectance of the target material layer. Therefore, the parameter estimation method of this embodiment can estimate the optical parameters of the target material even if it is a non-self-supporting film material by using at least one of the total transmittance, rectilinear transmittance, and reflectance of the composite layer and the optical parameters of the support material.

[0058] The thickness of the support layer in the composite layer may be the same as or different from the thickness of the support layer in the support measurement value indicated by the support measurement value information.

[0059] The composite layer measurement value acquiring section 140 may acquire composite layer measurement value information related to composite layer measurement values ​​measured by the measurement device 200. The composite layer measurement value acquiring section 140 may acquire the composite layer measurement value information from the measurement device 200.

[0060] The predetermined wavelength may be one wavelength or multiple wavelengths. For example, it may be multiple wavelengths in the ultraviolet-visible region. When the predetermined wavelength is multiple wavelengths, the composite layer measurement value information may include composite layer measurement value information for each of the multiple wavelengths, or may include only composite layer measurement value information for the wavelength used to estimate the optical parameters.

[0061] The target material estimation unit 150 estimates the optical parameters of the target material based on at least one of the composite layer measurement values ​​of the total transmittance, rectilinear transmittance, and reflectance of each of the multiple composite layers and the optical parameters of the support material estimated by the support estimation unit 130, and stores composite layer estimation result information regarding the estimated results in the memory unit 110.

[0062] The target material estimation unit 150 can estimate the optical parameters of the target material, for example, using the reverse Monte Carlo method, based on the composite layer measurement values ​​of at least one of the total transmittance, rectilinear transmittance, and reflectance of each of the multiple composite layers and the optical parameters of the support material estimated by the support estimation unit 130.

[0063] Specifically, the target material estimation unit 150 searches for and estimates optical parameters of the target material that minimizes an evaluation function that evaluates the error between the composite layer measurement values ​​acquired by the composite layer measurement value acquisition unit 140 and the composite layer calculated values, which are at least one of the total transmittance, rectilinear transmittance, and reflectance of each of the multiple composite layers calculated based on the generated optical parameters of the target material and the optical parameters of the support material estimated by the support estimation unit 130.

[0064] The target material estimation unit 150 generates optical parameters of the target material and calculates a composite layer calculated value, which is at least one of the total transmittance, rectilinear transmittance, and reflectance of each of the multiple composite layers, based on the generated optical parameters of the target material and the optical parameters of the support material estimated by the support estimation unit 130. The target material estimation unit 150 compares the calculated composite layer value with the composite layer measurement value indicated by the composite layer measurement value information. The target material estimation unit 150 repeats the process of generating the optical parameters of the target material, calculating the calculated composite layer value, and comparing it with the composite layer measurement value. This repetition may be performed a number of times set by an administrator of the parameter estimation system 100, or may end when the value of an evaluation function (described later) reaches a predetermined value. The repetition method may be the same as or different from the repetition method used by the support estimation unit 130. The method for calculating the calculated values ​​of the total transmittance, rectilinear transmittance, and reflectance of the composite layer is the same as the calculation method used by the support estimation unit 130.

[0065] The target material estimation unit 150 then estimates the optical parameters that most accurately reproduce the composite layer measurement values ​​as the optical parameters of the target material. At this time, the target material estimation unit 150 may use, for example, an evaluation function that evaluates the error between the composite layer calculation value and the composite layer measurement value. The evaluation function may be, for example, the sum of squares of the errors between each calculation value (calculated values ​​of total transmittance, rectilinear transmittance, and reflectance) and each measurement value (measured values ​​of total transmittance, rectilinear transmittance, and reflectance), or may be the square root of the sum of squares. The evaluation function may be the same as or different from the evaluation function in the support estimation unit 130.

[0066] In this way, the target material estimation unit 150 can generate optical parameters and estimate appropriate optical parameters by comparing the composite layer calculated values ​​of total transmittance, rectilinear transmittance, and reflectance based on the generated optical parameters with the composite layer measured values.

[0067] The reason why the parameter estimation method of this embodiment can estimate optical parameters with high accuracy is presumed to be as follows.

[0068] Conventional parameter estimation methods did not take into account changes in the thickness of the target material, so optical parameters were estimated using only one measurement value obtained from a target material of a certain thickness. In this case, multiple optical parameters (scattering coefficient μ s , extinction coefficient μ a , scattering anisotropy parameter g), there may be multiple optimal solutions that minimize the error between the measured value and the calculated value. In particular, when the target material is strongly affected by absorption and scattering (for example, when it is a composite material), the total transmittance, rectilinear transmittance, and reflectance of the target material also depend greatly on the film thickness of the target material. Therefore, even if an optical parameter can accurately reproduce the measured value of a target material with a certain film thickness, it may not be able to accurately reproduce the measured value of a target material with a different film thickness.

[0069] In this regard, the parameter estimation system 100 of this embodiment estimates optical parameters using measurements of multiple composite layers formed by laminating layers of a target material with different thicknesses on a support layer, thereby enabling highly accurate estimation of the optical parameters of the target material. The thickness of the target material layer does not affect the optical parameters of the target material. Therefore, by measuring multiple composite layers formed by layers of the target material with different thicknesses, multiple measurements can be obtained for a target material having the same optical parameters, measured under different conditions. In this way, because the optical parameters are estimated based on multiple measurements, it is believed that optical parameters can be estimated with high accuracy and reproducible even for measurements of different film thicknesses.

[0070] Next, the parameter estimation system of this embodiment will be explained using an example in which the total transmittance, rectilinear transmittance, and reflectance are obtained as measured values ​​for five composite layers having target material layers stacked with five different film thicknesses.

[0071] The target material estimation unit 150 estimates the optical parameters of the target material based on at least one of the measured values ​​of the total transmittance, rectilinear transmittance, and reflectance for at least two of the five composite layers. In this case, the target material estimation unit 150 may estimate based on the measured values ​​of all five composite layers. Alternatively, the target material estimation unit 150 may compare the calculated values ​​of the total transmittance, rectilinear transmittance, and reflectance using measured values ​​of different combinations of composite layers.

[0072] Although estimating the optical parameters based on many measured values ​​for many composite layers is desirable from the viewpoint of estimating the optical parameters with high accuracy, the calculation process may be complicated and require a huge amount of time, so the optical parameters may be estimated based on specific measured values ​​for a specific composite layer. Specifically, the target material estimation unit 150 can search for and estimate the optical parameters of the target material that minimizes an evaluation function that evaluates the error between at least one or more measured values ​​of the total transmittance, rectilinear transmittance, and reflectance for each of three composite layers having at least three different film thicknesses (e.g., a first film thickness, a second film thickness, and a third film thickness) among the five film thicknesses, and at least one or more calculated values ​​of the total transmittance, rectilinear transmittance, and reflectance for each of the at least three composite layers calculated based on the generated optical parameters of the target material.

[0073] Here, the first film thickness may be, for example, a film thickness that is thinner than the average (or may be the median) of the plurality of film thicknesses, particularly, for example, the thinnest film thickness. The second film thickness may be, for example, a film thickness that is thicker than the average (or may be the median) of the plurality of film thicknesses, particularly, for example, the thickest film thickness. The third film thickness may be, for example, the average (median) film thickness of the plurality of film thicknesses.

[0074] The total transmittance is roughly proportional to the film thickness, and the tendency of the proportional relationship for each of a plurality of wavelengths is roughly consistent. Therefore, appropriate optical parameters can be estimated by using measured values ​​at two different film thicknesses, for example, a thin film thickness and a thick film thickness, particularly, for example, the thinnest film thickness and the thickest film thickness.

[0075] FIG. 5A is an image diagram showing the relationship between film thickness and total transmittance at different wavelengths. In FIG. 5A, the horizontal axis represents film thickness, and the vertical axis represents total transmittance. In FIG. 5A, the graph showing the highest total transmittance represents the measurement results at a wavelength of 405 nm, the graph showing the second highest total transmittance represents the measurement results at a wavelength of 385 nm, and the graph showing the lowest total transmittance represents the measurement results at a wavelength of 365 nm. As described above, since the relationship between film thickness and total transmittance is roughly proportional, the target material estimation unit 150 can estimate optical parameters of the target material layer that can accurately reproduce the total transmittance by, for example, using the measured value (511) of the total transmittance for the thinnest film thickness as the first film thickness and the measured value (512) of the total transmittance for the thickest film thickness as the second film thickness.

[0076] Furthermore, the rectilinear transmittance has the property of converging to 0 as the film thickness increases, and the convergence tendency is generally the same. Therefore, appropriate optical parameters can be estimated by using the measured values ​​at one film thickness, for example, a thin film thickness, particularly, for example, the thinnest film thickness.

[0077] FIG. 5B is an image diagram showing the relationship between film thickness and rectilinear transmittance at different wavelengths. In FIG. 5B, the horizontal axis represents film thickness, and the vertical axis represents rectilinear transmittance. In FIG. 5B, the graph showing the highest rectilinear transmittance at the thinnest film thickness represents the measurement results at a wavelength of 405 nm, the graph showing the second highest rectilinear transmittance at the thinnest film thickness represents the measurement results at a wavelength of 385 nm, and the graph showing the lowest rectilinear transmittance at the thinnest film thickness represents the measurement results at a wavelength of 365 nm. As such, the rectilinear transmittance converges to zero as the film thickness increases, and the convergence trend is generally similar. Therefore, by using the measured value (521) of the rectilinear transmittance at the thinnest film thickness as the first film thickness, it is possible to estimate the optical parameters of the target material layer that can accurately reproduce the rectilinear transmittance.

[0078] Furthermore, the degree of consistency in the tendency of the relationship between the film thickness and the reflectance at each of multiple wavelengths is low, and the reflectance does not have the property of converging to a constant value. Therefore, appropriate optical parameters can be estimated by using measured values ​​at three different film thicknesses, for example, a thin film thickness, a medium film thickness, and a thick film thickness, particularly, for example, the thinnest film thickness, the medium film thickness, and the thickest film thickness.

[0079] FIG. 5C is an image diagram showing the relationship between film thickness and reflectance at different wavelengths. In FIG. 5C, the horizontal axis represents film thickness, and the vertical axis represents reflectance. In FIG. 5C, the graph showing the highest reflectance at the thinnest film thickness represents the measurement results at a wavelength of 405 nm, the graph showing the second highest reflectance at the thinnest film thickness represents the measurement results at a wavelength of 385 nm, and the graph showing the lowest reflectance at the thinnest film thickness represents the measurement results at a wavelength of 365 nm. As described above, the reflectances of the relationship between film thickness and reflectance at each of multiple wavelengths do not tend to coincide with each other and do not converge to a constant value. Therefore, the target material estimation unit 150 can estimate optical parameters of the target material layer that can accurately reproduce the reflectance by, for example, using the measured value (531) of the reflectance at the thinnest film thickness as the first film thickness, the measured value (532) of the reflectance at the intermediate (average) film thickness as the third film thickness, and the measured value (533) of the reflectance at the thickest film thickness as the second film thickness.

[0080] In this way, when there are measured values ​​for four or more composite layers having four or more different film thicknesses, the optical parameters can be estimated accurately with a small amount of calculation by estimating the optical parameters based on at least the measured values ​​of the total transmittance, rectilinear transmittance, and reflectance for the first film thickness, the measured values ​​of the total transmittance and reflectance for the second film thickness, and the measured value of the reflectance for the third film thickness, as described above.

[0081] The notations "first to third" are merely given formally to distinguish and explain the respective film thicknesses, and are not intended to indicate an order or sequence.

[0082] Furthermore, when searching for and estimating the optical parameters of the target material, the target material estimation unit 150 may use the measured value of the refractive index of the target material, and may also search for and estimate the refractive index of the support material at the same time. The method of measuring the refractive index of the target material and the method of searching for the refractive index are the same as those of the support estimation unit 130.

[0083] Next, an example of a hardware configuration in which the parameter estimation system 100 is realized by a computer 600 will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example of a hardware configuration of the computer 600.

[0084] As shown in FIG. 6, a computer 600 includes, for example, a processor 601, a memory 602, a storage device 603, an input I / F unit 604, a data I / F unit 605, a communication I / F unit 606, and a display device 607.

[0085] Computer 600 may be, for example, a server computer, a personal computer (e.g., desktop, laptop, tablet, etc.), a media computing platform (e.g., cable, satellite set-top box, digital video recorder, etc.), a handheld computing device (e.g., PDA, email client, etc.), or any other type of computing or communications platform.

[0086] The processor 601 is a control unit that controls various processes in the computer 600 by executing programs stored in the memory 602 .

[0087] The memory 602 is a storage medium such as a RAM (Random Access Memory), etc. The memory 602 temporarily stores the program code of the program executed by the processor 601 and data required when the program is executed.

[0088] The storage device 603 is a non-volatile storage medium such as a hard disk drive (HDD), flash memory, etc. The storage device 603 stores an operating system and various programs for realizing the above-mentioned configurations.

[0089] The input I / F unit 604 is a device for receiving input from a user. The input I / F unit 604 is, for example, a keyboard, a mouse, a touch panel, various sensors, a wearable device, etc. The input I / F unit 604 may be connected to the computer 600 via an interface such as a USB (Universal Serial Bus).

[0090] The data I / F unit 605 is a device for inputting data from outside the computer 600. The data I / F unit 605 is, for example, a drive device for reading data stored in various storage media. The data I / F unit 605 may be provided outside the computer 600. When the data I / F unit 605 is provided outside the computer 600, the data I / F unit 605 is connected to the computer 600 via an interface such as a USB.

[0091] The communication I / F unit 606 is a device for performing data communication via a network such as the Internet, either wired or wirelessly, with devices external to the computer 600. The communication I / F unit 606 may be provided outside the computer 600. When the communication I / F unit 606 is provided outside the computer 600, the communication I / F unit 606 is connected to the computer 600 via an interface such as a USB.

[0092] The display device 607 is a device for displaying various types of information. The display device 607 is, for example, a liquid crystal display, an organic EL (Electro-Luminescence) display, a display of a wearable device, or the like. The display device 607 may be provided outside the computer 600. When the display device 607 is provided outside the computer 600, the display device 607 is connected to the computer 600 via, for example, a display cable. Furthermore, when a touch panel is adopted as the input I / F unit 604, the display device 607 may be configured as an integral part of the input I / F unit 604.

[0093] An embodiment of the present invention has been described above. The parameter estimation system 100 can acquire support measurement values, estimate optical parameters of the support material based on the support measurement values, acquire composite layer measurement values, and estimate optical parameters of the target material based on the composite layer measurement values ​​and the optical parameters of the support material. This allows the parameter estimation system 100 to accurately estimate the optical parameters of various materials, particularly materials whose total transmittance, rectilinear transmittance, and reflectance are difficult to measure.

[0094] The parameter estimation system 100 can also search for and estimate optical parameters of a support material that minimize an evaluation function that evaluates the error between support measurement values, which are at least one of the total transmittance, rectilinear transmittance, and reflectance at a predetermined film thickness of a support layer made of the support material, and support calculation values, which are at least one of the total transmittance, rectilinear transmittance, and reflectance calculated based on the generated optical parameters of the support material. The parameter estimation system 100 can also search for and estimate optical parameters of a target material that minimize an evaluation function that evaluates the error between composite layer measurement values, which are at least one of the total transmittance, rectilinear transmittance, and reflectance for each of multiple composite layers formed by laminating layers made of a target material with different film thicknesses on a support layer, and composite layer calculation values, which are at least one of the total transmittance, rectilinear transmittance, and reflectance for each of multiple composite layers calculated based on the generated optical parameters of the target material and the optical parameters of the support material. This allows the parameter estimation system 100 to estimate the optical parameters of various materials with high accuracy using the reverse Monte Carlo method.

[0095] Furthermore, the parameter estimation system 100 can search for and estimate optical parameters of the target material that minimize an evaluation function that evaluates the error between the measured value of the total transmittance of each of two composite layers including layers made of the target material having at least a first film thickness and a second film thickness, and the calculated value of the total transmittance of each of the at least two composite layers calculated based on the generated optical parameters of the target material and the optical parameters of the support material. This allows the parameter estimation system 100 to reduce the calculation load using the evaluation function and estimate optical parameters with high accuracy.

[0096] Furthermore, the parameter estimation system 100 can search for and estimate optical parameters of a target material that minimize an evaluation function that evaluates the error between a measured value of the rectilinear transmittance of a composite layer including a layer made of the target material having at least a first thickness and a calculated value of the rectilinear transmittance of a composite layer including a layer made of the target material having at least a first thickness, the calculated value being calculated based on the generated optical parameters of the target material and the optical parameters of a support material. This allows the parameter estimation system 100 to reduce the calculation load using the evaluation function and estimate optical parameters with high accuracy.

[0097] Furthermore, the parameter estimation system 100 can search for and estimate optical parameters of a target material that minimize an evaluation function that evaluates the error between measured values ​​of reflectance for each of three composite layers including layers made of the target material having at least a first film thickness, a second film thickness, and a third film thickness, and calculated values ​​of reflectance for each of the at least three composite layers calculated based on the generated optical parameters of the target material and the optical parameters of the support material. This allows the parameter estimation system 100 to reduce the load of calculations using the evaluation function and estimate optical parameters with high accuracy.

[0098] Furthermore, the parameter estimation system 100 can estimate the optical parameters of a target material that is a composite material made of multiple materials and is a non-self-supporting film material for which it is difficult to measure the total transmittance, rectilinear transmittance, and reflectance of a target material layer made only of the target material, particularly a target material that is a photosensitive resin composition, for example. This allows the parameter estimation system 100 to estimate the optical parameters of various materials with high accuracy.

[0099] It should be noted that the present embodiment is provided to facilitate understanding of the present invention and is not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and equivalents thereof are also included in the present invention.

[0100] In addition, in the present invention, a "unit" does not simply mean a physical means, but also includes cases where the functions of the "unit" are realized by software. Furthermore, the functions of one "unit" or device may be realized by two or more physical means, devices, or software, and the functions of two or more "units" or devices may be realized by one physical means, device, or software. [Explanation of symbols]

[0101] 100 Parameter estimation system, 110 Memory unit, 120 Support measurement value acquisition unit, 130 Support estimation unit, 140 Composite layer measurement value acquisition unit, 150 Target material estimation unit, 200 Measurement device

Claims

1. The computer a support measurement value acquisition step of acquiring a support measurement value, which is at least one of total transmittance, rectilinear transmittance, and reflectance at a predetermined film thickness of a support layer consisting only of a support material, by optical measurement using light of a predetermined wavelength; a support estimation step of estimating optical parameters including an absorption coefficient, a scattering coefficient, and a scattering anisotropy parameter of the support material based on the support measurement values ​​acquired in the support measurement value acquisition step; a composite layer measurement value acquisition step of acquiring a composite layer measurement value, which is at least one of total transmittance, rectilinear transmittance, and reflectance, for each of a plurality of composite layers formed by laminating layers made of a target material with different thicknesses on the support layer, by optical measurement using light of a predetermined wavelength; a target material estimation step of estimating the optical parameters of the target material based on the composite layer measurement values ​​acquired in the composite layer measurement value acquisition step and the optical parameters of the support material estimated in the support estimation step; Parameter estimation methods including:

2. the support estimation step includes searching for and estimating optical parameters of the support material that minimize an evaluation function that evaluates an error between the support measurement values ​​acquired in the support measurement value acquisition step and the support calculated values, which are at least one of total transmittance, rectilinear transmittance, and reflectance, calculated based on the generated optical parameters of the support material; The target material estimation step includes searching for and estimating the optical parameters of the target material, which minimizes an evaluation function that evaluates an error between the composite layer measurement values ​​of each of the plurality of composite layers acquired in the composite layer measurement value acquisition step, and composite layer calculated values, which are at least one of total transmittance, rectilinear transmittance, and reflectance of each of the plurality of composite layers, calculated based on the generated optical parameters of the target material and the optical parameters of the support material estimated in the support estimation step. The parameter estimation method according to claim 1 .

3. the target material estimation step includes searching for and estimating optical parameters of the target material, which minimizes an evaluation function that evaluates an error between a measured value of total transmittance of each of two composite layers including layers made of a target material having at least a first film thickness and a second film thickness, and a calculated value of total transmittance of each of at least the two composite layers calculated based on the generated optical parameters of the target material and the optical parameters of the support material estimated in the support estimation step; The parameter estimation method according to claim 2 .

4. the target material estimation step includes searching for and estimating optical parameters of the target material that minimize an evaluation function that evaluates an error between a measured value of a rectilinear transmittance of a composite layer including a layer made of the target material having at least a first film thickness and a calculated value of a rectilinear transmittance of a composite layer including a layer made of the target material having at least a first film thickness, the calculated value being calculated based on the generated optical parameters of the target material and the optical parameters of the support material estimated in the support estimation step; The parameter estimation method according to claim 2 .

5. the target material estimation step includes searching for and estimating optical parameters of the target material, which minimizes an evaluation function that evaluates an error between measured values ​​of reflectance of each of three composite layers including layers made of the target material having at least a first film thickness, a second film thickness, and a third film thickness, and calculated values ​​of reflectance of each of the at least three composite layers calculated based on the generated optical parameters of the target material and the optical parameters of the support material estimated in the support estimation step; The parameter estimation method according to claim 2 .

6. The parameter estimation method according to any one of claims 1 to 5, wherein the target material is a composite material made of a plurality of materials, and is a non-freestanding film material for which it is difficult to measure the total transmittance, rectilinear transmittance, and reflectance of a target layer made of only the target material.

7. The parameter estimation method according to claim 6 , wherein the target material is a photosensitive resin composition.

8. a support measurement value acquisition unit that acquires support measurement values, which are at least one of total transmittance, rectilinear transmittance, and reflectance, at a predetermined film thickness of a support layer made only of a support material by optical measurement using light of a predetermined wavelength; a support estimation unit that estimates optical parameters including an absorption coefficient, a scattering coefficient, and a scattering anisotropy parameter of the support material based on the support measurement values ​​acquired by the support measurement value acquisition unit; a composite layer measurement value acquisition unit that acquires composite layer measurement values, which are at least one of total transmittance, rectilinear transmittance, and reflectance, for each of a plurality of composite layers formed by laminating layers made of a target material with different thicknesses on the support layer, by optical measurement using light of a predetermined wavelength; a target material estimation unit that estimates the optical parameters of the target material based on the composite layer measurement values ​​acquired by the composite layer measurement value acquisition unit and the optical parameters of the support material estimated by the support estimation unit; A parameter estimation system comprising:

9. On the computer, a support measurement value acquisition process for acquiring support measurement values, which are at least one of total transmittance, rectilinear transmittance, and reflectance at a predetermined film thickness of a support layer made only of a support material, by optical measurement using light of a predetermined wavelength; a support estimation process for estimating optical parameters including an absorption coefficient, a scattering coefficient, and a scattering anisotropy parameter of the support material based on the support measurement values ​​acquired in the support measurement value acquisition process; a composite layer measurement value acquisition process for acquiring, by optical measurement using light of a predetermined wavelength, composite layer measurement values ​​that are at least one of total transmittance, rectilinear transmittance, and reflectance for each of a plurality of composite layers formed by laminating layers made of a target material with different thicknesses on the support layer, the plurality of composite layers having layers made of the target material with different thicknesses; a target material estimation process for estimating the optical parameters of the target material based on the composite layer measurement values ​​acquired in the composite layer measurement value acquisition process and the optical parameters of the support material estimated in the support estimation process; Parameter estimation program for executing the above.

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