Method Of Measuring Refractive Index and Thickness Of Thin Film Multiple Layer Using Spectroscopic Ellipsometry

Abstract

The present invention provides a method for measuring the refractive index and thickness of a thin film multilayer comprising first to m thin films disposed on a substrate and sequentially disposed from top to bottom, comprising the steps of: converting the substrate having a substrate refractive index and the second to m thin films, each having a second to m refractive index, into an effective substrate having a p-polarized effective refractive index and an s-polarized effective refractive index; and calculating the refractive index or thickness of the first thin film using the p-polarized effective refractive index, the s-polarized effective refractive index, a first reflection coefficient at the interface between the incident medium and the first thin film, and a zeroe reflection coefficient at the interface between the incident medium and the effective substrate.

Description

Technology Field

[0001] The present invention relates to a method for measuring the refractive index and thickness of a thin film multilayer, and more particularly to a method for measuring the refractive index and thickness of a thin film multilayer using deterministic reflection contrast ellipsometry based on an effective substrate conversion method. Background Technology

[0002] With the development of industry and the trend toward high density and integration, the number of devices requiring thin films is increasing, and a significant portion of these devices is being replaced by thin films. Furthermore, as technology advances, there is a growing need for thin films with uniform thicknesses ranging from a few to tens of nanometers in integrated circuits, optoelectronic devices, and display devices. In addition, thin films are emerging as a critical component in various application fields, such as insulating and active layers in semiconductor devices, transparent electrodes in liquid crystal displays, and light-emitting and protective layers in light-emitting diode displays.

[0003] As thin film thickness is a parameter that significantly affects yield and reliability, the need for real-time measurement of thin film thickness is increasing for the control of semiconductor manufacturing processes.

[0004] Spectroscopic ellipsometry (SE) has been proposed as a method to measure the thickness of thin films by measuring the change in polarization of transmitted or reflected light to calculate the refractive index and thickness of each of the multiple thin films.

[0005] In ellipsometry, the ratio of the reflection coefficient (ρ) of p-polarization (parallel polarization) to s-polarization (vertical polarization) of incident light is measured, and the ratio of the reflection coefficient (ρ) can be expressed by the following Equation 1.

[0006] [Formula 1]

[0007]

[0008] Here, ρ is the reflection ratio, R(p) is the reflection ratio of the p-polarized incident light, R(s) is the reflection ratio of the s-polarized incident light, Ψ is the amplitude ratio angle, tan(Ψ) is the amplitude ratio, and Δ is the phase difference.

[0009] In ellipsometry, to calculate the refractive index and thickness of each of multiple thin films, a specific dispersion model is assumed for the refractive index spectrum corresponding to the physical properties of each film. The refractive index and thickness of each film are then calculated by fitting a dispersion model that reproduces the measured amplitude ratio (tan(Ψ)) and phase difference (Δ) through regression analysis.

[0010] However, the regression analysis process based on the material's variance model requires prior knowledge of the material's properties, and there is a problem in that one or more local minimums are generated during the refractive index regression analysis process, resulting in a value that differs from the global minimum corresponding to the material's actual refractive index. The problem to be solved

[0011] The present invention was devised to solve the aforementioned problems and aims to provide a method for measuring the refractive index and thickness of a multiple thin film layer, wherein the refractive index and thickness of each of the multiple thin films are calculated solely from the spectra of the amplitude ratio and phase difference measured without using a dispersion model of the material, by utilizing deterministic reflection contrast ellipsometry based on an effective substrate conversion method, thereby preventing errors caused by local minimums and improving the measurement accuracy of the calculated refractive index and thickness. means of solving the problem

[0012] To achieve the above objective, the present invention provides a method for measuring the refractive index and thickness of a thin film multilayer comprising first to m thin films disposed on a substrate and sequentially disposed from top to bottom, the method comprising: a step of converting the substrate having a substrate refractive index and the second to m thin films, each having a second to m refractive index, into an effective substrate having a p-polarized effective refractive index and an s-polarized effective refractive index; and a step of calculating the refractive index or thickness of the first thin film using the p-polarized effective refractive index, the s-polarized effective refractive index, a first reflection coefficient at the interface between the incident medium and the first thin film, and a zeroe reflection coefficient at the interface between the incident medium and the effective substrate.

[0013] And, the step of converting to the effective substrate comprises: a step of calculating a first optical path length from the first refractive index of the first thin film, the first wavenumber of the refracted light, the first thickness of the first thin film, and the angle of refraction of the refracted light according to Formula 6 below; and a step of calculating a p-polarized β function and an s-polarized β function from the p-polarized 1s reflection coefficient at the interface between the first thin film and the substrate, the s-polarized 1s reflection coefficient at the interface between the first thin film and the substrate, and the first optical path length according to Formulas 4 and 5 below; The method may include a step of calculating the p-polarized effective refractive index and s-polarized effective refractive index of the effective substrate from the angle of incidence of the incident light, the angle of refraction of the refractive light, the zero refractive index of the incident medium, the first refractive index of the first thin film, the p-polarized β function, and the s-polarized β function according to the following formulas 2 and 3.

[0014] [Formula 2]

[0015]

[0016] [Equation 3]

[0017]

[0018] (n e (p) is the p-polarized effective refractive index of the effective substrate, ne (s) is the s-polarized effective refractive index of the effective substrate, θ0 is the angle of incidence of the incident light, θ1 is the angle of refraction of the refractive light, n0 is the zero refractive index of the incident medium, n1 is the first refractive index of the first thin film, β(p) is the p-polarized β function, β(s) is the s-polarized β function)

[0019] [Equation 4]

[0020]

[0021] [Formula 5]

[0022]

[0023] (β(p) is the p-polarized β function, β(s) is the s-polarized β function, R 1s (p) is the p-polarized first s reflection coefficient at the interface between the first thin film and the substrate, R 1s (s) is the first s-polarization reflection coefficient at the interface between the first thin film and the substrate, and φ1 is the first optical path length of light of the first wavenumber inside the first thin film)

[0024] [Equation 6]

[0025]

[0026] (φ1 is the first optical path length of light of the first wavenumber inside the first thin film, n1 is the first refractive index of the first thin film, k1 is the first wavenumber of the light, d1 is the first thickness of the first thin film, θ1 is the angle of refraction of the refracted light)

[0027] Additionally, the step of calculating the refractive index or thickness of the first thin film comprises: a step of measuring the p-polarized 01 reflection coefficient at the interface between the incident medium and the first thin film, the s-polarized 01 reflection coefficient at the interface between the incident medium and the first thin film, the p-polarized 0e reflection coefficient at the interface between the incident medium and the effective substrate, and the s-polarized 0e reflection coefficient at the interface between the incident medium and the effective substrate; and a step of calculating the reflection coefficient ratio of the first thin film, the reflection coefficient ratio of the effective substrate, and the difference in the reflection coefficient ratio between the first thin film and the effective substrate from the p-polarized 01 reflection coefficient, the s-polarized 01 reflection coefficient, the p-polarized 0e reflection coefficient, and the s-polarized 0e reflection coefficient according to the following Equations 11 to 13; The method may include the step of calculating function A, function B, and function α from the p-polarized effective refractive index of the effective substrate, the zero refractive index of the incident medium, the wavelength of the incident light, and the first thickness of the first thin film according to the following formulas 8 to 10; and the step of calculating the first refractive index of the first thin film from the zero refractive index of the incident medium, the function A, the function B, the function α, and the difference in the reflection coefficient ratio according to the following formula 7.

[0028] [Formula 7]

[0029]

[0030] (n1 is the first refractive index of the first thin film, n0 is the zero refractive index of the incident medium, A, B, and α are the functions A, B, and α, respectively, and δ is the difference in the ratio of reflection coefficients between the first thin film and the effective substrate)

[0031] [Equation 8]

[0032]

[0033] [Formula 9]

[0034]

[0035] [Formula 10]

[0036]

[0037] (A, B, and α are function A, function B, function α, and n, respectively)e (p) is the p-polarized effective refractive index of the effective substrate, n0 is the zero refractive index of the incident medium, λ is the wavelength of the incident light, and d1 is the first thickness of the first thin film)

[0038] [Equation 11]

[0039]

[0040] (ρ1 is the first reflection coefficient ratio of the first thin film, ρ e is the effective reflection coefficient ratio of the effective substrate)

[0041] [Equation 12]

[0042]

[0043] [Equation 13]

[0044]

[0045] (ρ1 is the first reflection coefficient ratio of the first thin film, R 01 (p) is the p-polarization first reflection coefficient, R at the interface between the incident medium and the first thin film. 01 (s) is the 01st reflection coefficient of s-polarization at the interface between the incident medium and the first thin film, Ψ 01 Ψ is the first amplitude ratio angle at the interface between the incident medium and the first thin film, tan(Ψ 01 ) is the 01st amplitude ratio at the interface between the incident medium and the first thin film, Δ 01 ε is the 01st phase difference, ρ at the interface between the incident medium and the first thin film. e is the e-reflection coefficient ratio of the effective substrate, R 0e (p) is the p-polarization zero-e reflection coefficient at the interface between the incident medium and the effective substrate, R 0e (s) is the s-polarization e-reflection coefficient, Ψ at the interface between the incident medium and the effective substrate 0e θ is the zero-e amplitude ratio angle at the interface between the incident medium and the effective substrate, tan(Ψ 0e ) is the zeroe amplitude ratio at the interface between the incident medium and the effective substrate, Δ 0e is the zeroe phase difference at the interface between the incident medium and the effective substrate)

[0046] And, the step of measuring the p-polarized 01st reflection coefficient, the s-polarized 01st reflection coefficient, the p-polarized 0e reflection coefficient, and the s-polarized 0e reflection coefficient may include: the step of measuring the 0s reflection coefficient at the interface between the incident medium and the substrate; the step of forming the m-th thin film on the substrate to measure the m-th reflection coefficient at the interface between the incident medium and the m-th thin film; and the step of sequentially forming the (m-1) to the first thin film on the m-th thin film to measure the 0(m-1) to 01st reflection coefficients at the interface between the incident medium and the (m-1) to the first thin film.

[0047] Additionally, the step of measuring the p-polarized first reflection coefficient, the s-polarized first reflection coefficient, the p-polarized first reflection coefficient, and the s-polarized first reflection coefficient may include the step of measuring the first reflection coefficient at the interface between the incident medium and the substrate; and the step of forming the first thin film on the substrate and measuring the first reflection coefficient at the interface between the incident medium and the first thin film.

[0048] And, the step of calculating the refractive index or thickness of the first thin film comprises: a step of measuring the p-polarized first reflection coefficient at the interface between the incident medium and the first thin film, the s-polarized first reflection coefficient at the interface between the incident medium and the first thin film, the p-polarized first e reflection coefficient at the interface between the first thin film and the effective substrate, and the s-polarized first e reflection coefficient at the interface between the first thin film and the effective substrate; and a step of calculating the C function, D function, E function, F function, G function, and H function from the p-polarized first reflection coefficient, the s-polarized first reflection coefficient, the p-polarized first e reflection coefficient, and the s-polarized first e reflection coefficient according to the following Equations 17 to 22; The method may include the step of calculating a function χ from the first reflection coefficient ratio of the first thin film, the C function, the D function, the E function, the F function, the G function, and the H function according to the following Equation 16; the step of calculating a function γ from the wavelength of the incident light, the first refractive index of the first thin film, and the angle of refraction of the refracted light according to the following Equation 15; and the step of calculating a first thickness of the first thin film from the function γ and the function χ according to the following Equation 14.

[0049] [Equation 14]

[0050]

[0051] (d1 is the first thickness of the first thin film, γ and χ are the γ function and χ function, respectively)

[0052] [Formula 15]

[0053]

[0054] [Equation 16]

[0055]

[0056] (d1 is the first thickness of the first thin film, λ is the wavelength of the incident light, n1 is the first refractive index of the first thin film, θ1 is the angle of refraction of the refracted light, ρ1 is the first reflection coefficient ratio of the first thin film, C, D, E, F, G, H are the functions C, D, E, F, G, and H, respectively)

[0057] [Equation 17]

[0058]

[0059] [Equation 18]

[0060]

[0061] [Formula 19]

[0062]

[0063] [Equation 20]

[0064]

[0065] [Equation 21]

[0066]

[0067] [Equation 22]

[0068]

[0069] (C, D, E, F, G, H are the C function, D function, E function, F function, G function, H function, R, respectively 01 (p) is the p-polarization first reflection coefficient, R at the interface between the incident medium and the first thin film. 01 (s) is the 01st reflection coefficient of s-polarization at the interface between the incident medium and the first thin film, R 1e (p) is the p-polarization first e-reflection coefficient at the interface between the first thin film and the effective substrate, R 1e (s) is the s-polarization first e reflection coefficient at the interface between the first thin film and the effective substrate) Effects of the invention

[0070] The present invention has the effect of preventing errors caused by local minimums and improving the measurement accuracy of the calculated refractive index and thickness by calculating the refractive index and thickness of each of a plurality of thin films using only the spectra of the amplitude ratio and phase difference measured without using a dispersion model of the material, by utilizing deterministic reflection contrast ellipsometry based on the effective substrate conversion method. Brief explanation of the drawing

[0071] FIG. 1 is a cross-sectional view of a thin film single layer and an effective substrate to explain the effective substrate conversion method of the thin film multilayer refractive index and thickness measurement method according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a thin film multilayer and an effective substrate to explain the effective substrate conversion method of the method for measuring the refractive index and thickness of a thin film multilayer according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a method for measuring the reflection coefficient of a thin film multilayer according to an embodiment of the present invention, which is a method for measuring the refractive index and thickness of a thin film multilayer. FIG. 4 is a diagram illustrating a method for measuring the reflection coefficient of a single thin film layer according to an embodiment of the present invention, which is a method for measuring the refractive index and thickness of a thin film multilayer. FIGS. 5A and FIGS. 5B are drawings illustrating the simulation results of the refractive index and error of a thin film single layer by the method for measuring the refractive index and thickness of a thin film multilayer according to an embodiment of the present invention. FIGS. 6a and FIGS. 6b are drawings illustrating the measurement results of the real and imaginary parts of the refractive index of a single thin film layer by the method for measuring the refractive index and thickness of a thin film multilayer layer according to an embodiment of the present invention. Specific details for implementing the invention

[0072] Hereinafter, the specific details of the present invention will be described in detail with reference to the attached drawings.

[0073] FIG. 1 is a cross-sectional view of a thin film single layer and an effective substrate to explain the effective substrate conversion method of the thin film multilayer refractive index and thickness measurement method according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a thin film multilayer and an effective substrate to explain the effective substrate conversion method of the thin film multilayer refractive index and thickness measurement method according to an embodiment of the present invention.

[0074] As illustrated in FIGS. 1 and 2, the method for measuring the refractive index and thickness of a thin film multilayer according to an embodiment of the present invention utilizes deterministic reflection contrast ellipsometry (DRCE) based on effective substrate reduction, wherein the effective substrate reduction method substitutes the substrate (SB) and the thin film single layer on top of the substrate (SB) with an effective substrate (ES) having the same reflection characteristics.

[0075] As shown in FIG. 1, the substrate refractive index (n s A first thin film (TF1) having a first refractive index (n1) and a first thickness (d1) is disposed on a substrate (SB) having ), and in ellipsometry, when the substrate (SB) having the first thin film (TF1) is placed in an incident medium (IM) having a zero refractive index (n0), incident light (Li) is irradiated onto the first thin film (TF1), and the reflected light (Lr) emitted from the first thin film (TF1) is measured, and the ratio of the intensity of the reflected light (Lr) to the intensity of the incident light (Li) is the first reflection coefficient (R) at the interface between the incident medium (IM) and the first thin film (TF1). 01 Calculate as ).

[0076] Here, the effective refractive index (n e It can be assumed that when an effective substrate (ES) having ) is placed in an incident medium (IM), incident light (Li) is irradiated onto the effective substrate (ES) and reflected light (Lr) is emitted from the effective substrate (ES). Since the incident light (Li) irradiated onto the effective substrate (ES) is the same as the incident light (Li) irradiated onto the first thin film (TF1), and the reflected light (Lr) emitted from the effective substrate (ES) is the same as the reflected light (Lr) emitted from the first thin film (TF1), the zeroe reflection coefficient (R) at the interface between the incident medium (IM) and the effective substrate (ES) 0e ) is the first reflection coefficient (R) at the interface between the incident medium (IM) and the first thin film (TF1). 01 It can be assumed to be the same as ).

[0077] Accordingly, the first reflection coefficient (R) is determined by the incident light (Li) and reflected light (Lr). 01 A substrate (SB) and a first thin film (TF1) having ) have a first reflection coefficient (R) due to the same incident light (Li) and reflected light (Lr). 01 The zeroth reflection coefficient (R) identical to ) 0e It can be interpreted as an effective substrate (ES) having ).

[0078] As shown in FIG. 2, the substrate refractive index (n s A thin film multilayer is disposed on a substrate (SB) having ), wherein the thin film multilayer comprises first to m thin films (TF1 to TF) sequentially disposed from top to bottom. m ...including ), the first thin film (TF1) has a first refractive index (n1) and a first thickness (d1), the second thin film (TF2) has a second refractive index (n2) and a second thickness (d2), and the (m-1) thin film (TF m-1 ) is the (m-1) refractive index (n m-1 ) and the first thickness (d m-1 Having ), the m thin film (TF m ) is the m-th refractive index (n m ) and m thickness (d m has ).

[0079] With a substrate (SB) having a thin film multilayer placed in an incident medium (IM) having a zero refractive index (n0), incident light (Li) is irradiated onto the uppermost layer, a first thin film (TF1), and the reflected light (Lr) emitted from the first thin film (TF1) is measured to determine the ratio of the intensity of the reflected light (Lr) to the intensity of the incident light (Li) as the zero-1 reflection coefficient (R) at the interface between the incident medium (IM) and the first thin film (TF1). 01 Calculate as ).

[0080] Here, the substrate (SB) and the bottom layer, the m-thin film (TF m ) is the m-th effective refractive index (n em Since it can be interpreted as a substitution with the m-th effective substrate (ESm) having ), the substrate (SB) and the m-th to 1st thin film (TF) on the upper surface of the substrate (SB) mTF1) is the m-th effective substrate (ESm) and the (m-1) to 1st thin film (TF) on top of the m-th effective substrate (ESm). m-1 It can be interpreted as a substitution for TF1).

[0081] The m-th effective substrate (ES m ) and the (m-1) thin film (TF m-1 ) is the (m-1) effective refractive index (n e(m-1) The (m-1) effective substrate (ES) having ) m-1 Since it can be interpreted as a substitution of ), the substrate (SB) and the m to 1st thin film (TF) on the upper surface of the substrate (SB) m TF1) is the (m-1) effective substrate (ES m-1 ) and the (m-1) effective substrate (ES m-1 ) upper part (m-2) to first thin film (TF m-2 It can be interpreted as a substitution for TF1).

[0082] This substitution interpretation is applied to the (m-2) to the second thin film (TF m-2 When continuously applied to TF2), the m-th to 1st thin film (TF) on the substrate (SB) and the upper surface of the substrate (SB) m TF1) is the effective refractive index (n e It can be interpreted as a substitute for an effective substrate (ES) having ) and a first thin film (TF1) which is a single layer on top of the effective substrate (ES).

[0083] That is, it can be assumed that when the effective substrate (ES) and the first thin film (TF1) on the upper part of the effective substrate (ES) are placed in the incident medium (IM), incident light (Li) is irradiated onto the first thin film (TF1) on the upper part of the effective substrate (ES), and then reflected light (Lr) is emitted from the first thin film (TF1) on the upper part of the effective substrate (ES). The incident light (Li) irradiated onto the first thin film (TF1) on the upper part of the effective substrate (ES) is identical to the incident light (Li) irradiated onto the first thin film (TF1), which is the uppermost layer of the thin film multilayer on the upper part of the substrate (SB), and the reflected light (Lr) emitted from the first thin film (TF1) on the upper part of the effective substrate (ES) is identical to the reflected light (Lr) emitted from the first thin film (TF1), which is the uppermost layer of the thin film multilayer on the upper part of the substrate (SB), so that at the interface between the incident medium (IM) and the first thin film (TF1), which is the uppermost layer of the thin film multilayer on the upper part of the effective substrate (ES). 01st reflection coefficient (R 01 ) is the first reflection coefficient (R) at the interface of the first thin film (TF1) on the upper surface of the incident medium (IM) and the substrate (SB). 01 It can be assumed to be the same as ).

[0084] Accordingly, the first reflection coefficient (R) is determined by the incident light (Li) and reflected light (Lr). 01 A substrate (SB) having ) and a thin film multilayer have the same first reflection coefficient (R) due to the same incident light (Li) and reflected light (Lr). 01 It can be interpreted as an effective substrate (ES) and a first thin film (TF1) having ).

[0085] Accordingly, in the method for measuring the refractive index and thickness of a thin film multilayer according to an embodiment of the present invention, through the effective substrate conversion method, the substrate (SB) and the second to m-th thin films (TF2 to TF) on the upper surface of the substrate (SB) m By converting ) into an effective substrate (ES), the first to m thin films (TF1 to TF), which are thin film multilayers on the substrate (SB) and the substrate (SB), m ) can be simplified into an effective substrate (ES) and a first thin film (TF1) on top of the effective substrate (ES).

[0086] Accordingly, the measured 01st reflection coefficient (R 01 )(or the 01st reflection coefficient(R 01 By using the amplitude ratio (tan(Ψ)) and phase difference (Δ) corresponding to ), the first refractive index (n1) and thickness (d1) of the first thin film (TF1) can be definitively calculated without using a dispersion model, and similarly, the second to m-th refractive indices (n2 to n) of the second to m-th thin films (TF2 to TFm) m ) and the second to m thicknesses (d2 to d m The thickness can be calculated definitively.

[0087] Here, the p-polarized effective refractive index (n) of the effective substrate (ES) for p-polarization. e (p)) and the s-polarization effective refractive index (n) of the effective substrate (ES) for s-polarization e (s)) can be expressed by the following Equation 2 and Equation 3, respectively.

[0088] [Formula 2]

[0089]

[0090] [Equation 3]

[0091]

[0092] Here, θ0 is the angle of incidence of the incident light (Li), θ1 is the angle of refraction of the refracted light (Lt), n0 is the zero refractive index of the incident medium (IM), n1 is the first refractive index of the first thin film (TF1), β(p) is the p-polarized β function, and β(s) is the s-polarized β function.

[0093] The p-polarized β function (β(p)) and the s-polarized β function (β(s)) can be expressed by the following Equations 4 and 5, respectively.

[0094] [Equation 4]

[0095]

[0096] [Formula 5]

[0097]

[0098] Here, R 1s(p) is the p-polarized first s reflection coefficient, R at the interface between the first thin film (TF1) and the substrate (SB) (or effective substrate (ES)). 1s (s) is the first s-polarization reflection coefficient at the interface between the first thin film (TF1) and the substrate (SB) (or effective substrate (ES)), and φ1 is the first optical path length of light of the first wavenumber (k1) inside the first thin film (TF1).

[0099] The p-polarized first s reflection coefficient (R) at the interface between the first thin film (TF1) and the substrate (SB) 1s (p)) and s-polarization first s-reflection coefficient (R 1s (s)) are the p-polarized first reflection coefficient (R) at the interface of the incident medium (IM) and the first thin film (TF1) measured by the Fresnel formula, respectively. 01 (p)) and s-polarized first reflection coefficient (R 01 It can be calculated from (s)).

[0100] The length of the first optical path (φ1) can be expressed by the following Equation 6.

[0101] [Equation 6]

[0102]

[0103] Here, n1 is the first refractive index of the first thin film (TF1), k1 is the first wavenumber of light, d1 is the first thickness of the first thin film (TF1), and θ1 is the angle of refraction of the refracted light (Lt).

[0104] According to Formulas 4 to 6, the first refractive index (n1) of the first thin film (TF1), the first wavenumber (k1) of light, the first thickness (d1) of the first thin film (TF1), the angle of refraction (θ1) of the refracted light (Lt), and the first s-refractive coefficient (R) of p-polarized light at the interface between the first thin film (TF1) and the substrate (SB). 1s (p)) and s-polarization first s-reflection coefficient (R 1sFrom (s)), the p-polarization β function (β(p)) and the s-polarization β function (β(s)) are calculated, and according to Equations 2 and 3, the incident angle (θ0) of the incident light (Li), the refraction angle (θ1) of the refracted light (Lt), the zero refractive index (n0) of the incident medium (IM), the first refractive index (n1) of the first thin film (TF1), the p-polarization effective refractive index (n) of the effective substrate (ES) for p-polarization is calculated from the p-polarization β function (β(p)) and the s-polarization β function (β(s)). e (p)) and the s-polarization effective refractive index (n) of the effective substrate (ES) for s-polarization e (s)) can be produced.

[0105] Accordingly, the angle of incidence (θ0), angle of refraction (θ1), and p-polarization first s-reflection coefficient (R) measured according to Equations 2 to 6 1s (p)), s-polarization first s-reflection coefficient (R 1s (s)) and the first thickness (d1) and first refractive index (n1) of the known first thin film (TF1) to determine the p-polarized effective refractive index (n e (p)) and s-polarized effective refractive index (n e (s)) can be produced.

[0106] Meanwhile, the measured 01st reflection coefficient (R 01 )(or the 01st reflection coefficient(R 01 The first refractive index (n1) and first thickness (d1) of the first thin film (TF1) can be calculated using the amplitude ratio (tan(Ψ)) and phase difference (Δ) corresponding to ) and Equations 2 to 6.

[0107] First, if the first thickness (d1) of the first thin film (TF1) is known, the first refractive index (n1) of the first thin film (TF1) can be expressed by the following Equation 7.

[0108] [Formula 7]

[0109]

[0110] Here, n0 is the zero refractive index of the incident medium (IM), A, B, and α are functions, and δ is the reflection ratio contrast between the first thin film (TF1) and the effective substrate (ES) (or substrate (SB)).

[0111] Functions A, B, and α can each be expressed by the following Equations 8 to 10.

[0112] [Equation 8]

[0113]

[0114] [Formula 9]

[0115]

[0116] [Formula 10]

[0117]

[0118] Here, n e (p) is the p-polarized effective refractive index of the effective substrate (ES) (or substrate (SB)), n0 is the zero refractive index of the incident medium (IM), λ is the wavelength of the incident light (Li), and d1 is the first thickness of the first thin film (TF1).

[0119] The difference in reflection coefficient ratio (δ) can be expressed by the following Equation 11.

[0120] [Equation 11]

[0121]

[0122] Here, ρ1 is the first reflection coefficient ratio of the first thin film (TF1), ρ e is the ratio of the effective reflection coefficient of the effective substrate (ES) (or substrate (SB)).

[0123] The first reflection coefficient ratio (ρ1) of the first thin film (TF1) and the effective reflection coefficient ratio (ρ) of the effective substrate (ES) (or substrate (SB) e ) can be expressed by the following Equations 12 and 13, which correspond to Equation 1, respectively.

[0124] [Equation 12]

[0125]

[0126] [Equation 13]

[0127]

[0128] Here, ρ1 is the first reflection coefficient ratio of the first thin film (TF1), R 01 (p) is the p-polarization first reflection coefficient, R at the interface between the incident medium (IM) and the first thin film (TF1). 01 (s) is the s-polarization first reflection coefficient, Ψ at the interface between the incident medium (IM) and the first thin film (TF1). 01 Ψ is the first amplitude ratio angle at the interface between the incident medium (IM) and the first thin film (TF1), tan(Ψ 01 ) is the 01st amplitude ratio, Δ at the interface between the incident medium (IM) and the first thin film (TF1). 01 is the 01st phase difference at the interface between the incident medium (IM) and the first thin film (TF1), and ρ e is the e-reflection coefficient ratio of the effective substrate (ES) (or substrate (SB)), R 0e (p) is the p-polarization zero-e reflection coefficient at the interface between the incident medium (IM) and the effective substrate (ES) (or substrate (SB)), R 0e (s) is the s-polarization e-reflection coefficient, Ψ at the interface between the incident medium (IM) and the effective substrate (ES) (or substrate (SB)). 0e θ is the zeroe amplitude ratio angle at the interface between the incident medium (IM) and the effective substrate (ES) (or substrate (SB)), tan(Ψ 0e ) is the zeroe amplitude ratio at the interface between the incident medium (IM) and the effective substrate (ES) (or substrate (SB)), Δ 0e is the zero e phase difference at the interface between the incident medium (IM) and the effective substrate (ES) (or substrate (SB)).

[0129] p-polarized first e-reflection coefficient (R) at the interface between the first thin film (TF1) and the effective substrate (ES) 1e (p)) and s-polarized first e reflection coefficient (R 1e (s)) are the p-polarized first reflection coefficient (R) measured by the Fresnel formula, respectively. 01 (p)) and s-polarized first reflection coefficient (R 01 It can be calculated from (s)).

[0130] That is, the p-polarized first reflection coefficient (R) from the reflected light (Lr) generated by the incident light (Li) irradiated onto the first thin film (TF1) of the thin film multilayer on the upper surface of the substrate (SE). 01 (p)) and s-polarized first reflection coefficient (R 01 Detect (s)) and the p-polarized first e-reflection coefficient (R) by the Fresnel formula 1e (p)) and s-polarized first e reflection coefficient (R 1e (s)) can be produced.

[0131] According to Formulas 11 to 13, the p-polarized first reflection coefficient (R 01 (p)), s-polarization first reflection coefficient (R 01 (s)), p-polarization first e reflection coefficient (R 1e (p)) and s-polarized first e reflection coefficient (R 1e Calculate the difference in reflection coefficient ratio (δ) from (s)), and the p-polarized effective refractive index (n) of the effective substrate (ES) (or substrate (SB)) according to Equations 8 to 10. e (p)), s-polarized effective refractive index (n) of the effective substrate (ES) (or substrate (SB)). e Functions A, B, and α can be calculated from the first thickness (d1) of the first thin film (TF1) (s), and the first refractive index (n1) of the first thin film (TF1) can be calculated from the difference (δ) between the reflection coefficient ratio and functions A, B, and α according to Equation 7.

[0132] Accordingly, the p-polarized first reflection coefficient (R) measured according to Equations 12 and 13 01 (p)) and s-polarized first reflection coefficient (R 01 The first refractive index (n1) of the first thin film (TF1) can be calculated using Equations 7 to 10 from (s)) and the first thickness (d1) of the first thin film (TF1) that is known.

[0133] Meanwhile, if the first refractive index (n1) of the first thin film (TF1) is known, the first thickness (d1) of the first thin film (TF1) can be expressed by the following Equation 14.

[0134] [Equation 14]

[0135]

[0136] Here, γ and χ are functions, respectively.

[0137] The functions γ and χ can be expressed by the following Equations 15 and 16, respectively.

[0138] [Formula 15]

[0139]

[0140] [Equation 16]

[0141]

[0142] Here, λ is the wavelength of the incident light (Li), n1 is the first refractive index of the first thin film (TF1), θ1 is the angle of refraction of the refracted light (Lt), ρ1 is the ratio of the first reflection coefficient of the first thin film (TF1), and C, D, E, F, G, and H are each functions.

[0143] Functions C, D, E, F, G, and H can each be expressed by the following Equations 17 through 22.

[0144] [Equation 17]

[0145]

[0146] [Equation 18]

[0147]

[0148] [Formula 19]

[0149]

[0150] [Equation 20]

[0151]

[0152] [Equation 21]

[0153]

[0154] [Equation 22]

[0155]

[0156] Here, R 01(p) is the p-polarization first reflection coefficient, R at the interface between the incident medium (IM) and the first thin film (TF1). 01 (s) is the 01st reflection coefficient of s-polarization at the interface between the incident medium (IM) and the first thin film (TF1), R 1e (p) is the p-polarized first e-reflection coefficient at the interface between the first thin film (TF1) and the effective substrate (ES) (or substrate (SB)), R 1e (s) is the s-polarization first e reflection coefficient at the interface between the first thin film (TF1) and the effective substrate (ES) (or substrate (SB)).

[0157] The p-polarized first e-reflection coefficient (R) at the interface between the first thin film (TF1) and the effective substrate (ES) (or substrate (SB)) 1e (p)) and s-polarized first e reflection coefficient (R 1e (s)) are the p-polarized first reflection coefficient (R) measured by the Fresnel formula, respectively. 01 (p)) and s-polarized first reflection coefficient (R 01 It can be calculated from (s)).

[0158] That is, the p-polarized first reflection coefficient (R) from the reflected light (Lr) generated by the incident light (Li) irradiated onto the first thin film (TF1) of the thin film multilayer on the upper surface of the substrate (SB). 01 (p)) and s-polarized first reflection coefficient (R 01 Detect (s)) and the p-polarized first e-reflection coefficient (R) by the Fresnel formula 1e (p)) and s-polarized first e reflection coefficient (R 1e (s)) can be produced.

[0159] According to Formulas 14 to 22, the p-polarized first reflection coefficient (R 01 (p)), s-polarization first reflection coefficient (R 01 (s)), p-polarization first e reflection coefficient (R 1e (p)) and s-polarized first e reflection coefficient (R 1eFunctions C, D, E, F, G, and H can be calculated from (s), the first reflection coefficient ratio (ρ1) according to Equation 16, the function χ from functions C, D, E, F, G, and H, the function γ from the wavelength (λ) of the incident light (Li), the first refractive index (n1) of the first thin film (TF1), and the angle of refraction (θ1) of the refractive light (Lt) according to Equation 15, and the first thickness (d1) of the first thin film (TF1) can be calculated from functions γ and χ according to Equation 14.

[0160] Accordingly, the p-polarized first reflection coefficient (R) measured according to Equations 14 to 22 01 (p)) and s-polarized first reflection coefficient (R 01 The first thickness (d1) of the first thin film (TF1) can be calculated from (s)) and the first refractive index (n1) of the first thin film (TF1) that is known.

[0161] Meanwhile, in order to calculate the first refractive index (n1) of the first thin film (TF1) according to Equations 7 to 10, the p-polarized first reflection coefficient (R 01 (p)), s-polarization first reflection coefficient (R 01 (s)), p-polarization first e reflection coefficient (R 1e (p)), s-polarization first e reflection coefficient (R 1e (s)) must be measured to calculate the difference (δ) in the reflection coefficient ratio between the first thin film (TF1) and the effective substrate (ES) (or substrate (SB)), which will be explained with reference to the drawing.

[0162] FIG. 3 is a drawing for explaining the method for measuring the reflection coefficient of a single thin film layer according to an embodiment of the present invention, and FIG. 4 is a drawing for explaining the method for measuring the reflection coefficient of a single thin film layer according to an embodiment of the present invention, and the explanation is given with reference to FIG. 1 and FIG. 2 together.

[0163] As illustrated in FIG. 3, in the method for measuring the refractive index and thickness of a thin film multilayer according to an embodiment of the present invention, the substrate refractive index (n sWhen a substrate (SB) having ) is placed in an incident medium (IM) having a zero refractive index (n0), incident light is irradiated onto the substrate (SB), and the reflected light is measured to determine the ratio of the intensity of the reflected light to the intensity of the incident light, which is the zeros reflection coefficient (R) at the interface between the incident medium (IM) and the substrate (SB). 0s Calculate as ).

[0164] Subsequently, a first thin film (TF1) having a first refractive index (n1) and a first thickness (d1) is formed on the substrate (SB). Then, with the substrate (SB) having the first thin film (TF1) placed in an incident medium (IM), incident light is irradiated onto the first thin film (TF1), and the reflected light is measured. The ratio of the intensity of the reflected light to the intensity of the incident light is the first reflection coefficient (R) at the interface between the incident medium (IM) and the first thin film (TF1). 01 Calculate as ).

[0165] The zeroth reflection coefficient (R) for p-polarization and s-polarization 0s ) and the 01st reflection coefficient (R 01 From the ratio of ), according to Equations 12 and 13, the first reflection coefficient ratio (ρ1) of the first thin film (TF1) and the e-reflection coefficient ratio (ρ) of the effective substrate (ES) (or substrate (SB)) e ) can be calculated. Accordingly, if the thickness of the first thin film (TF1) is known, the refractive index of the first thin film (TF1) can be calculated according to Equation 7, or if the refractive index of the first thin film (TF1) is known, the thickness of the first thin film (TF1) can be calculated according to Equation 14.

[0166] As illustrated in FIG. 4, in the method for measuring the refractive index and thickness of a thin film multilayer according to an embodiment of the present invention, the substrate refractive index (n s When a substrate (SB) having ) is placed in an incident medium (IM) having a zero refractive index (n0), incident light is irradiated onto the substrate (SB), and the reflected light is measured to determine the ratio of the intensity of the reflected light to the intensity of the incident light, which is the zeros reflection coefficient (R) at the interface between the incident medium (IM) and the substrate (SB). 0s Calculate as ).

[0167] Subsequently, on the upper part of the substrate (SB), the m-th refractive index (n m ) and m thickness (d m ) having a m thin film (TF m After forming ), the m thin film (TF m With a substrate (SB) having ) placed in an incident medium (IM), the m-th thin film (TF m After irradiating incident light onto ), the reflected light is measured to determine the ratio of the intensity of the reflected light to the intensity of the incident light between the incident medium (IM) and the m thin film (TF m The zeroth reflection coefficient (R) at the interface of ) 0m Calculate as ).

[0168] Subsequently, the m thin film (TF m ) The (m-1) refractive index (n) at the top m-1 ) and the (m-1)th thickness (d m-1 The (m-1)th thin film (TF) having ) m-1 After forming ), the (m-1) thin film (TF m-1 With a substrate (SB) having ) placed in an incident medium (IM), the (m-1) thin film (TF m-1 After irradiating incident light onto ), the reflected light is measured to determine the ratio of the intensity of the reflected light to the intensity of the incident light between the incident medium (IM) and the first (m-1) thin film (TF m-1 The zero (m-1) reflection coefficient (R) at the interface of ) 0(m-1) Calculate as ).

[0169] Subsequently, the (m-1) thin film (TF m-1 ) on top of the (m-2) thin film (TF m-2 While sequentially forming the ) to the second thin film (TF2), the 0 (m-2) to the 02 reflection coefficient (R 0(m-2) to R 02 ) calculates.

[0170] Subsequently, a first thin film (TF1) having a first refractive index (n1) and a first thickness (d1) is formed on the second thin film (TF2), and while the substrate (SB) having the first thin film (TF1) is placed in an incident medium (IM), incident light is irradiated onto the first thin film (TF1), and the reflected light is measured to determine the ratio of the intensity of the reflected light to the intensity of the incident light, which is the first reflection coefficient (R) at the interface between the incident medium (IM) and the first thin film (TF1). 01 Calculate as ).

[0171] The 0th reflection coefficient (R) at each interface 0s From ) the 0th m reflection coefficient (R 0m ), zeroth (m-1) reflection coefficient (R 0(m-1) ), 01st reflection coefficient (R 01 When ) is calculated, the ratio of reflection coefficients for p-polarized and s-polarized light at each interface can be calculated according to Equations 12 and 13. Accordingly, if the thickness of the top thin film is known, the refractive index of the top thin film can be calculated according to Equation 7, or if the refractive index of the top thin film is known, the thickness of the top thin film can be calculated according to Equation 14.

[0172] For example, in the case of FIG. 4, the refractive index or thickness of the top thin film (TF1) can be determined by Equation 7 or Equation 14, and this process can be applied to the bottom thin film (TF m By repeating up to ), the refractive index or thickness of each thin film can all be determined.

[0173] FIGS. 5a and 5b are drawings illustrating the simulation results of the refractive index and error of a single thin film layer according to the method for measuring the refractive index and thickness of a multilayer thin film according to an embodiment of the present invention, and FIGS. 6a and 6b are drawings illustrating the measurement results of the real and imaginary parts of the refractive index of a single thin film layer according to the method for measuring the refractive index and thickness of a multilayer thin film according to an embodiment of the present invention, respectively, and will be explained with reference to FIGS. 1 to 4 together.

[0174] In FIG. 5a, FIG. 5b, FIG. 6a, FIG. 6b, when a second thin film (TF2) of silicon oxide (SiO2) having a second thickness (d2) of about 280 nm and a first thin film (TF1) of molybdenum disulfide (MoS2) having a first thickness (d1) at the atomic layer level are sequentially formed on a silicon substrate (SB), the reflection coefficient of the first thin film (TF1) is measured in the state of the substrate (SB), the second thin film (TF2), and the first thin film (TF1), and the reflection coefficient of the second thin film (TF2) is measured in the state of the substrate (SB) and the second thin film (TF2), and the first refractive index (n1) of the first thin film (TF1) can be calculated according to Equations 2 to 13.

[0175] As shown in FIGS. 5a and 5b, as the angle of incidence (θ0) of the incident light (Li) increases and the energy (i.e., wavelength) of the incident light (Li) decreases, the refractive index (n, k) approaches the reference value and the error converges to 0.

[0176] Therefore, depending on the characteristics of the sample to be measured, the angle of incidence (θ0) of the incident light (Li) and the energy of the incident light (Li) can be determined to appropriate values.

[0177] As shown in FIGS. 6a and 6b, when the angle of incidence (θ0) of the incident light (Li) is fixed at about 40 degrees, the experimental refractive index (n, k) of the first thin film (TF1) of molybdenum disulfide (MoS2) differs from the theoretical and reference values ​​in the error region where the wavelength of the incident light (Li) is about 600 nm or less, but in the region where the wavelength of the incident light (Li) is greater than about 600 nm, the experimental refractive index (n, k) of the first thin film (TF1) of molybdenum disulfide (MoS2) matches the theoretical and reference values, thereby improving measurement accuracy.

[0178] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the technical spirit and scope of the invention as described in the following claims. Explanation of the symbols

[0179] SB: Substrate TF1 to TF m : 1st to mth thin film ES: Effective substrate IM: Incident medium Li: Incident light Lr: Reflected light Lt: Refracted light

Claims

Claim 1 A method for measuring the refractive index and thickness of a thin film multilayer comprising first to m thin films disposed on a substrate and sequentially disposed from top to bottom, comprising: a step of converting the substrate having a substrate refractive index and the second to m thin films, each having a second to m refractive index, into an effective substrate having a p-polarized effective refractive index and an s-polarized effective refractive index; and a step of calculating the refractive index or thickness of the first thin film using the p-polarized effective refractive index, the s-polarized effective refractive index, a first reflection coefficient at the interface between the incident medium and the first thin film, and a first reflection coefficient at the interface between the incident medium and the effective substrate, wherein the step of converting into an effective substrate comprises: a step of calculating a first optical path length from the first refractive index of the first thin film, the first wavenumber of the refracted light, the first thickness of the first thin film, and the angle of refraction of the refracted light according to the following Equation 6; and the first thin film according to the following Equations 4 and 5 A method for measuring the refractive index and thickness of a thin film multilayer, comprising: a step of calculating a p-polarized first s-reflection coefficient at the interface of the substrate, an s-polarized first s-reflection coefficient at the interface of the first thin film and the substrate, and a p-polarized β-function and an s-polarized β-function from the first optical path length; and a step of calculating the p-polarized effective refractive index and the s-polarized effective refractive index of the effective substrate from the angle of incidence of the incident light, the angle of refraction of the refracted light, the zero refractive index of the incident medium, the first refractive index of the first thin film, the p-polarized β-function, and the s-polarized β-function according to the following Equations 2 and 3. [Equation 2] [Equation 3] (n e (p) is the p-polarized effective refractive index of the effective substrate, n e (s) is the s-polarized effective refractive index of the effective substrate, θ0 is the angle of incidence of the incident light, θ1 is the angle of refraction of the refractive light, n0 is the zeroth refractive index of the incident medium, n1 is the first refractive index of the first thin film, β(p) is the p-polarized β function, β(s) is the s-polarized β function [Equation 4] [Formula 5] (β(p) is the p-polarized β function, β(s) is the s-polarized β function, R 1s (p) is the p-polarized first s reflection coefficient at the interface between the first thin film and the substrate, R 1s (s) is the first s-polarization reflection coefficient at the interface between the first thin film and the substrate, φ1 is the first optical path length of light of the first wavenumber inside the first thin film)[Equation 6] (φ1 is the first optical path length of light of the first wavenumber inside the first thin film, n1 is the first refractive index of the first thin film, k1 is the first wavenumber of the light, d1 is the first thickness of the first thin film, θ1 is the angle of refraction of the refracted light) Claim 2 delete Claim 3 A method for measuring the refractive index and thickness of a thin film multilayer comprising first to m thin films disposed on a substrate and sequentially disposed from top to bottom, comprising: a step of converting the substrate having a substrate refractive index and the second to m thin films, each having a second to m refractive index, into an effective substrate having a p-polarized effective refractive index and an s-polarized effective refractive index; and a step of calculating the refractive index or thickness of the first thin film using the p-polarized effective refractive index, the s-polarized effective refractive index, a first reflection coefficient at the interface between the incident medium and the first thin film, and a first reflection coefficient at the interface between the incident medium and the effective substrate, wherein the step of calculating the refractive index or thickness of the first thin film comprises the p-polarized first reflection coefficient at the interface between the incident medium and the first thin film, the s-polarized first reflection coefficient at the interface between the incident medium and the first thin film, and the p-polarized A step of measuring the zeroe reflection coefficient and the s-polarized zeroe reflection coefficient at the interface between the incident medium and the effective substrate; a step of calculating the reflection coefficient ratio of the first thin film, the reflection coefficient ratio of the effective substrate, and the difference in the reflection coefficient ratio between the first thin film and the effective substrate from the p-polarized zero1 reflection coefficient, the s-polarized zero1 reflection coefficient, the p-polarized zeroe reflection coefficient, and the s-polarized zeroe reflection coefficient according to Equations 11 to 13 below; a step of calculating function A, function B, and function α from the p-polarized effective refractive index of the effective substrate, the zero refractive index of the incident medium, the wavelength of the incident light, and the first thickness of the first thin film according to Equations 8 to 10 below; and a step of calculating the zero refractive index of the incident medium, function A, function B, function α, and reflection coefficient ratio according to Equation 7 below A method for measuring the refractive index and thickness of a thin film multilayer, comprising the step of calculating the first refractive index of the first thin film from the difference.[Equation 7] (n1 is the first refractive index of the first thin film, n0 is the zero refractive index of the incident medium, A, B, and α are the functions A, B, and α, respectively, and δ is the difference in the ratio of the reflection coefficients between the first thin film and the effective substrate)[Equation 8] [Formula 9] [Formula 10] (A, B, and α are function A, function B, function α, and n, respectively) e (p) is the p-polarized effective refractive index of the effective substrate, n0 is the zeroth refractive index of the incident medium, λ is the wavelength of the incident light, d1 is the first thickness of the first thin film)[Equation 11] (ρ1 is the first reflection coefficient ratio of the first thin film, ρ e is the ratio of the effective reflection coefficient of the effective substrate)[Equation 12] [Equation 13] (ρ1 is the first reflection coefficient ratio of the first thin film, R 01 (p) is the p-polarization first reflection coefficient, R at the interface between the incident medium and the first thin film. 01 (s) is the 01st reflection coefficient of s-polarization at the interface between the incident medium and the first thin film, Ψ 01 Ψ is the first amplitude ratio angle at the interface between the incident medium and the first thin film, tan(Ψ 01 ) is the 01st amplitude ratio at the interface between the incident medium and the first thin film, Δ 01 ε is the 01st phase difference, ρ at the interface between the incident medium and the first thin film. e is the e-reflection coefficient ratio of the effective substrate, R 0e (p) is the p-polarization zero-e reflection coefficient at the interface between the incident medium and the effective substrate, R 0e (s) is the s-polarization e-reflection coefficient, Ψ at the interface between the incident medium and the effective substrate 0e θ is the zero-e amplitude ratio angle at the interface between the incident medium and the effective substrate, tan(Ψ 0e ) is the zeroe amplitude ratio at the interface between the incident medium and the effective substrate, Δ 0e is the zeroe phase difference at the interface between the incident medium and the effective substrate) Claim 4 A method for measuring the refractive index and thickness of a thin film multilayer according to claim 3, wherein the step of measuring the p-polarized 01st reflection coefficient, the s-polarized 01st reflection coefficient, the p-polarized 0e reflection coefficient, and the s-polarized 0e reflection coefficient comprises: the step of measuring the 0s reflection coefficient at the interface between the incident medium and the substrate; the step of forming the m-th thin film on the substrate to measure the m-th reflection coefficient at the interface between the incident medium and the m-th thin film; and the step of sequentially forming the (m-1) to the first thin film on the m-th thin film to measure the 0(m-1) to 01st reflection coefficients at the interface between the incident medium and the (m-1) to the first thin film. Claim 5 A method for measuring the refractive index and thickness of a thin film multilayer, wherein, in claim 3, the step of measuring the p-polarized 01st reflection coefficient, the s-polarized 01st reflection coefficient, the p-polarized 0e reflection coefficient, and the s-polarized 0e reflection coefficient comprises: the step of measuring the 0s reflection coefficient at the interface between the incident medium and the substrate; and the step of forming the first thin film on the substrate and measuring the 01st reflection coefficient at the interface between the incident medium and the first thin film. Claim 6 A method for measuring the refractive index and thickness of a thin film multilayer comprising first to m thin films disposed on a substrate and sequentially disposed from top to bottom, comprising: a step of converting the substrate having a substrate refractive index and the second to m thin films, each having a second to m refractive index, into an effective substrate having a p-polarized effective refractive index and an s-polarized effective refractive index; and a step of calculating the refractive index or thickness of the first thin film using the p-polarized effective refractive index, the s-polarized effective refractive index, a first reflection coefficient at the interface between the incident medium and the first thin film, and a first reflection coefficient at the interface between the incident medium and the effective substrate, wherein the step of calculating the refractive index or thickness of the first thin film comprises the first p-polarized reflection coefficient at the interface between the incident medium and the first thin film, the first s-polarized reflection coefficient at the interface between the incident medium and the first thin film, and the p-polarized reflection coefficient at the interface between the first thin film and the effective substrate. A step of measuring the first e-reflection coefficient and the s-polarized first e-reflection coefficient at the interface between the first thin film and the effective substrate; a step of calculating the C function, D function, E function, F function, G function, and H function from the p-polarized first reflection coefficient, the s-polarized first reflection coefficient, the p-polarized first e-reflection coefficient, and the s-polarized first e-reflection coefficient according to the following Equations 17 to 22; a step of calculating the function χ from the first reflection coefficient ratio of the first thin film, the C function, the D function, the E function, the F function, the G function, and the H function according to the following Equation 16; a step of calculating the function γ from the wavelength of the incident light, the first refractive index of the first thin film, and the angle of refraction of the refracted light according to the following Equation 15; and from the function γ and the function χ according to the following Equation 14 A method for measuring the refractive index and thickness of a thin film multilayer, comprising the step of calculating the first thickness of the first thin film.[Equation 14] (d1 is the first thickness of the first thin film, γ and χ are the γ function and χ function, respectively)[Equation 15] [Equation 16] (d1 is the first thickness of the first thin film, λ is the wavelength of the incident light, n1 is the first refractive index of the first thin film, θ1 is the angle of refraction of the refracted light, ρ1 is the first reflection coefficient ratio of the first thin film, C, D, E, F, G, H are the functions C, D, E, F, G, and H, respectively) [Equation 17] [Equation 18] [Formula 19] [Equation 20] [Equation 21] [Equation 22] (C, D, E, F, G, H are the C function, D function, E function, F function, G function, H function, R, respectively 01 (p) is the p-polarization first reflection coefficient, R at the interface between the incident medium and the first thin film. 01 (s) is the 01st reflection coefficient of s-polarization at the interface between the incident medium and the first thin film, R 1e (p) is the p-polarization first e-reflection coefficient at the interface between the first thin film and the effective substrate, R 1e (s) is the s-polarization first e reflection coefficient at the interface between the first thin film and the effective substrate)

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