A quasi-dynamic in-situ ellipsometric measurement method and system for photoresist exposure process

Abstract

The present invention belongs to the technical field related to optical thin film measurement, and discloses a quasi-dynamic in-situ ellipsometric measurement method and system for a photoresist exposure process. The method comprises: using a Mueller matrix ellipsometer to obtain a measured Mueller matrix of the photoresist at different exposure times; establishing a forward optical model of the photoresist to obtain a theoretical Mueller matrix; inverse fitting the measured Mueller matrix and the theoretical Mueller matrix to obtain the ellipsometric parameters, average extinction coefficient, and film thickness of the photoresist at different times; establishing a relationship model between the parameters of the photoresist and the optical properties of the photoresist, as well as an exposure model of the photoresist; establishing a relationship model between the theoretical extinction coefficient and the extinction coefficient to obtain the theoretical extinction coefficient of the photoresist after different exposure times; inverse fitting the average extinction coefficient and the theoretical extinction coefficient to obtain parameters. The present application can not only perform static measurement on the photoresist but also perform quasi-dynamic measurement on the exposure process of the photoresist, and can accurately characterize the exposure process of the photoresist.

Description

Technical Field

[0001] The present invention belongs to the technical field related to optical thin film measurement, and more specifically, relates to a quasi-dynamic in-situ ellipsometric measurement method and system for a photoresist exposure process. Background Art

[0002] The photoresist exposure process is a crucial step in the photolithography process, significantly impacting the final chip quality. Measuring and studying the changes in photoresist properties during exposure is crucial for refining the photolithography process and improving photoresist performance. When exposed to ultraviolet light, photoresist undergoes a photochemical reaction, altering its geometry and optical properties as the reaction progresses. Specific process parameters are often refined empirically and lack sufficient theoretical support. However, traditional transmission measurement methods ignore the changes in photoresist geometry during exposure, resulting in relatively simple results and difficulty in fully characterizing the photoresist exposure process.

[0003] Ellipsometry is a very effective method for thin film measurement. It is non-destructive, non-contact, and has fast measurement speeds. It is often used to characterize various metal and non-metallic thin film materials. Ellipsometry is used to measure the geometric parameters and optical properties of photoresist by preparing it into a thin film. Compared with traditional transmission measurement methods, it does not require the photoresist to be spin-coated onto glass with a similar refractive index, which is more suitable for practical application scenarios. In addition, the Mueller matrix ellipsometer can obtain a large amount of sample optical information in a single measurement, from which geometric and optical parameters such as the sample's thickness, roughness, refractive index, and extinction coefficient can be extracted. The measurement data is very rich and is conducive to characterizing the geometric and optical properties of photoresist.

[0004] Ellipsometry is a model-based measurement technique whose measurement accuracy depends largely on the accuracy of the established model. However, during the exposure process, the optical properties of photoresist undergo nonlinear changes with exposure time. Previous measurement experiments only performed static measurements on photoresist, lacking dynamic measurements of the photoresist exposure process. Consequently, there is a lack of a dynamic model of the photoresist exposure process, making it difficult to accurately characterize the photoresist exposure process. Therefore, there is an urgent need to provide a more accurate and complete measurement method for the photoresist exposure process. Summary of the Invention

[0005] In response to the above-mentioned defects or improvement needs of the prior art, the present invention provides a quasi-dynamic in-situ ellipsometric measurement method and system for the photoresist exposure process. This method can not only perform static measurement of the photoresist but also perform quasi-dynamic measurement of the photoresist exposure process, thereby accurately characterizing the photoresist exposure process.

[0006] To achieve the above-mentioned object, according to one aspect of the present invention, a quasi-dynamic in-situ ellipsometric method for photoresist exposure process is provided, the method comprising: S1: using a Mueller matrix ellipsometer to measure the Mueller matrix information of the photoresist before exposure, exposing the photoresist and measuring it using the Mueller matrix ellipsometer until the Mueller matrix data remains unchanged, thereby obtaining the measured Mueller matrix of the photoresist; S2: treating the photoresist as a uniform film, establishing a forward optical model, and then obtaining a theoretical Mueller matrix; S3: performing inverse fitting between the measured Mueller matrix and the theoretical Mueller matrix to obtain the ellipsometric parameters of the photoresist at different times. number, average extinction coefficient and film thickness; S4: establishing a relationship model between the Dill parameter of the photoresist and the optical properties of the photoresist, as well as an exposure model of the photoresist, the optical properties include the extinction coefficient, the exposure light source wavelength, the exposure light intensity and the relative photoacid concentration of the photoresist, and the Dill parameters include the driftable coefficient, the non-driftable coefficient and the reaction rate constant; S5: establishing a relationship model between the theoretical extinction coefficient and the extinction coefficient, and obtaining the theoretical extinction coefficient of the photoresist after different exposure times; S6: performing inverse fitting on the average extinction coefficient and the theoretical extinction coefficient to obtain the Dill parameter.

[0007] In a further preferred embodiment, the relationship model between the Dill parameter of the photoresist and the optical properties of the photoresist in step S4 includes:

[0008] α=AM+B=4πk / λ

[0009]

[0010] Wherein, α is the absorption coefficient, M is the relative photoacid concentration at a certain position in the photoresist, k is the extinction coefficient, λ is the wavelength of the exposure light source, I is the exposure light intensity at the corresponding position, A is the bleachable coefficient, B is the non-bleachable coefficient, C is the reaction rate constant, ΔM is the change in relative photoacid concentration, and Δt is the change time.

[0011] In a further preferred embodiment, the exposure model is to divide the photoresist into T-layer thin film stacks with uniform thickness.

[0012] In a further preferred embodiment, the relationship model between the theoretical extinction coefficient and the extinction coefficient in step S5 is:

[0013]

[0014] Among them, k mod is the theoretical extinction coefficient, k z is the extinction coefficient, and T is the total thickness of the photoresist film.

[0015] In a further preferred embodiment, step S6 performs inverse fitting of the average extinction coefficient and the theoretical extinction coefficient, specifically by constructing a deviation function between the average extinction coefficient and the theoretical extinction coefficient, inputting the initial value of the Dill parameter and the film thickness, fitting the Dill parameter, and obtaining the Dill parameter with the goal of minimizing the deviation function.

[0016] In a further preferred embodiment, the deviation function between the average extinction coefficient and the theoretical extinction coefficient is:

[0017]

[0018] Among them, k mod (t) is the theoretical extinction coefficient at time t, k ave (t) is the average extinction coefficient at time t, and Q is the number of sampling points.

[0019] In a further preferred solution, in step S3, the inverse fitting of the measured Mueller matrix and the theoretical Mueller matrix is ​​specifically to construct a deviation function between the measured Mueller matrix and the theoretical Mueller matrix, and to solve the problem with the goal of minimizing the deviation function.

[0020] In a further preferred embodiment, the deviation function between the measured Mueller matrix and the theoretical Mueller matrix is:

[0021]

[0022] Among them, M mod is the theoretical Mueller matrix, M exp is the measured Mueller matrix, λ is the wavelength, and q is the number of wavelengths λ.

[0023] On the other hand, the present application provides a quasi-dynamic in-situ ellipsometric measurement system for a photoresist exposure process, the system comprising: a measurement module for measuring the Mueller matrix information of the photoresist before exposure using a Mueller matrix ellipsometer, exposing the photoresist and measuring it using the Mueller matrix ellipsometer until the Mueller matrix data remains unchanged, thereby obtaining the measured Mueller matrix of the photoresist; a first model building module for treating the photoresist as a uniform film, establishing a forward optical model, and then obtaining a theoretical Mueller matrix; a calculation module for inverse fitting the measured Mueller matrix and the theoretical Mueller matrix to obtain the ellipsometric parameters, average extinction coefficient, and and film thickness; a second model building module: used to establish a relationship model between the Dill parameter of the photoresist and the optical properties of the photoresist, as well as an exposure model of the photoresist, wherein the optical properties include the extinction coefficient, the wavelength of the exposure light source, the exposure light intensity and the relative photoacid concentration of the photoresist, and the Dill parameters include the driftable coefficient, the non-driftable coefficient and the reaction rate constant; a third model building module: used to establish a relationship model between the theoretical extinction coefficient and the extinction coefficient, and obtain the theoretical extinction coefficient of the photoresist after different exposure times; a second calculation module: used to inversely fit the average extinction coefficient and the theoretical extinction coefficient to obtain the Dill parameter.

[0024] In general, the above technical solutions conceived by the present invention, compared with the prior art, provide a quasi-dynamic in-situ ellipsometric measurement method and system for photoresist exposure process, which has the following beneficial effects:

[0025] 1. This application uses the above method to collect the dynamic ellipsometric parameters of the photoresist under different exposure powers; uses the constructed forward optical model of the photoresist to fit the measured ellipsometric parameters, and obtains the ellipsometric parameters and optical properties of the photoresist at different exposure reaction moments; and then uses the exposure model based on the Dill equation to fit the dynamic optical characteristic curve to determine the Dill parameters of the photoresist, realizing the advantages of in-situ quasi-dynamic measurement, easy integration into the production line, reaction process monitoring, and richer measurement information.

[0026] 2. The forward optical model of the photoresist used to analyze the ellipsometric measurement results is linked to the Dill parameter of the photoresist and the exposure dose. The Dill parameter of the photoresist can be accurately fitted by the ellipsometric analysis results during the exposure process.

[0027] 3. Compared with existing measurement methods, the above measurement experimental scheme and modeling analysis method conceived by the present invention can more accurately and completely characterize the dynamic changes in the geometric and optical properties of the photoresist exposure process, providing strong data support for the improvement of photoresist performance and further optimization of the photolithography process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1Schematic diagram of the experimental device for the photoresist exposure process according to an embodiment of the present application;

[0029] Figure 2 This is a step diagram of the quasi-dynamic in-situ ellipsometric measurement method for the photoresist exposure process according to an embodiment of the present application;

[0030] Figure 3 This is a flow chart of a quasi-dynamic in-situ ellipsometric measurement method for a photoresist exposure process according to an embodiment of the present application;

[0031] Figure 4 The forward optical model of the sample established in the embodiment of the present application regards the photoresist as a uniform thin film;

[0032] Figure 5 This is an exposure model established for photoresist in an embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0034] The experimental setup for the photoresist exposure process is as follows Figure 1 As shown, the exposure light source of the experimental bench is incident vertically on the photoresist through the lens group and the reflector in turn, and the measurement light source is incident obliquely on the photoresist through the reflector, polarizer P, and compensator C in turn. After being reflected by the photoresist, it is incident on the detector through the compensator C, analyzer A and the reflector.

[0035] In this embodiment, when the exposure light source used in the measurement experiment is a coherent light source, the standing wave effect caused by the interference of reflected light and incident light needs to be considered in the photoresist exposure model. In this case, the light intensity does not decrease monotonically with the incident depth.

[0036] See also Figure 2 and Figure 3 The present invention provides a quasi-dynamic in-situ ellipsometric measurement method for a photoresist exposure process, the method comprising the following steps S1 to S6.

[0037] S1: Using a Mueller matrix ellipsometer to measure the Mueller matrix information of the photoresist before exposure, the photoresist is exposed and measured using the Mueller matrix ellipsometer until the Mueller matrix data remains unchanged, thereby obtaining the measured Mueller matrix of the photoresist.

[0038] Specifically, the Mueller matrix information of the photoresist sample before exposure is measured using a Mueller matrix ellipsometer, and then the exposure light path is opened, the sample is irradiated for Δt time, and then closed, the sample position is kept unchanged, and the Mueller matrix information of the photoresist sample is measured again using the Mueller matrix ellipsometer. The exposure is repeated and the measurement process is repeated until the measured data no longer changes. The Mueller matrix M of the sample at wavelength λ measured by the Mueller matrix ellipsometer exp :

[0039]

[0040] It is preferred to use a wide spectrum ellipsometer for in-situ measurement. The position of the photoresist remains unchanged during exposure and measurement, eliminating the influence of uneven thickness of the photoresist at different positions and improving the measurement accuracy.

[0041] The ellipsometer used in this embodiment is a wide-spectrum Mueller matrix ellipsometer, and the exposure light source used is an incoherent commercial ultraviolet light source with a wavelength of 365nm. Taking the measurement of AZ5214E ​​photoresist film as an example, the quasi-dynamic measurement experimental method of the photoresist in the present invention is explained.

[0042] A 365nm UV exposure device based on Köhler illumination was integrated into a spectroscopic ellipsometer. The photoresist was exposed in segments at a lower power. In situ measurements were performed using a wide-spectrum Mueller matrix ellipsometer during the exposure intervals until the optical properties of the photoresist no longer changed. The exposure power was then changed, and the dynamic ellipsometric parameters of the photoresist at different exposure powers were collected using the above method.

[0043] Prepare a photoresist sample by spin coating on a 2-inch wafer, controlling the thickness to approximately 2000nm. Measure the Mueller matrix of the photoresist sample using an ellipsometer at an incident angle of 65° under yellow light or in a dark environment. After recording the data, maintain the photoresist in its original position on the sample stage. Turn on the UV light source, illuminate the photoresist sample for five seconds, then turn it off. Measure the Mueller matrix of the photoresist sample using the ellipsometer using the same measurement configuration. Record the data and repeat the exposure-measurement process until the directly measured Mueller matrix displayed on the ellipsometer no longer changes.

[0044] S2: Considering the photoresist as a uniform thin film, a forward optical model is established to obtain the theoretical Mueller matrix.

[0045] Specifically, the photoresist is initially regarded as a uniform film, and a forward optical model of the sample is established (e.g. Figure 4 The forward optical modeling method of the uniform thin film sample is a conventional modeling method in the field of ellipsometry measurement and will not be described here. For an isotropic uniform film, its theoretical Mueller matrix M at wavelength λ is mod for:

[0046]

[0047] Among them, ψ and Δ are the amplitude ratio and phase difference respectively, and the theoretical Mueller matrix M of the photoresist is mod (λ) and the measured Mueller matrix are inversely fitted to establish the deviation function between the theoretical Mueller matrix and the measured Mueller matrix. The fitting calculation is performed with the goal of minimizing the deviation function to obtain the ellipsometric parameters ψ and Δ of the photoresist sample at different times, and the average extinction coefficient k of the photoresist ave (λ) and film thickness d.

[0048] S3: performing inverse fitting on the measured Mueller matrix and the theoretical Mueller matrix to obtain the ellipsometric parameters, average extinction coefficient and film thickness of the photoresist at different times.

[0049] The measured Mueller matrix and the theoretical Mueller matrix are inversely fitted. The specific method is to construct a deviation function between the measured Mueller matrix and the theoretical Mueller matrix, and solve the problem with the goal of minimizing the deviation function.

[0050] The deviation function between the measured Mueller matrix and the theoretical Mueller matrix is:

[0051]

[0052] Among them, M mod is the theoretical Mueller matrix, M exp is the measured Mueller matrix, λ is the wavelength, and q is the number of wavelengths λ.

[0053] For reflective measurement, the following relationship exists at wavelength λ

[0054]

[0055] Among them, r p and r s It represents the total reflection coefficient of p-polarized light and s-polarized light at the incident wavelength λ, and can be obtained from the forward optical model of the thin film sample using the Fresnel formula.

[0056]

[0057]

[0058] Among them, β=2πdN1cosθ1 / λ, r ij，p is the reflectivity of light p on the interface between the i-th and j-th layers, r ij，s is the reflectivity of light s on the interface between the i-th and j-th layers, r 012 is the total reflectivity.

[0059] S4: Establish a relationship model between the Dill parameters of the photoresist and the optical properties of the photoresist, as well as an exposure model of the photoresist. The optical properties include the extinction coefficient, the exposure light source wavelength, the exposure light intensity, and the relative photoacid concentration of the photoresist. The Dill parameters include the driftable coefficient, the non-driftable coefficient, and the reaction rate constant.

[0060] The relationship model between the Dill parameter of photoresist and the optical properties of photoresist includes:

[0061] α=AM+B=4πk / λ (7)

[0062]

[0063] Wherein, α is the absorption coefficient, M is the relative photoacid concentration at a certain position in the photoresist, k is the extinction coefficient, λ is the wavelength of the exposure light source, I is the exposure light intensity at the corresponding position, A is the bleachable coefficient, B is the non-bleachable coefficient, C is the reaction rate constant, ΔM is the change in relative photoacid concentration, and Δt is the change time.

[0064] The exposure model divides the photoresist into a thin film stack with uniform thickness of T layers. Therefore, the exposure model can describe the change of the relative photoacid concentration inside the photoresist with exposure time and depth under a certain light intensity. Figure 5 As shown, the total thickness of the photoresist is d. The photoresist is layered into a thin film stack with T layers of uniform thickness. The larger T is, the higher the model accuracy is. Let T = 500. Taking the vertical incidence as an example, let the incident ultraviolet light intensity be I0, then the incident light intensity I at the jth layer is j for:

[0065]

[0066] In addition, the influence of the reflected light intensity at the photoresist / substrate interface needs to be considered. Assuming the reflection coefficient of the photoresist bottom surface is Ref, the reflected light intensity at the jth layer is:

[0067]

[0068] At t = 0, the relative photoacid concentration M in the photoresist is 1. Given the preset Dill parameters A and B, the total light intensity E of the photoresist can be calculated by formulas (9) and (10): j =I j +R j , and then use formula (8) to calculate the change ΔM of the relative photoacid concentration M after dt time, let t1 = dt, then:

[0069] M(j,t1)=M(j,t0)-ΔM(j,t0) (11)

[0070] The extinction coefficient k at the depth z in the photoresist can be calculated from the exposure model and the relationship model between the Dill parameter of the photoresist and the optical properties of the photoresist. z At t = 0, the photoresist has not been exposed, and the relative photoacid concentration M at all locations inside is 1. According to formula (7), the photoresist absorption coefficient α(z) at depth z, the incident light intensity here is:

[0071]

[0072] Specifically, the relative photoacid concentration distribution after time dt is calculated cyclically using formulas (8), (9), (10), and (11) until M at each layer is approximately 0. The extinction coefficient k(z, t) of the photoresist at different depths at different times can be calculated using formula (7) and I(z).

[0073] S5: establishing a relationship model between a theoretical extinction coefficient and the extinction coefficient, and obtaining the theoretical extinction coefficient of the photoresist after exposure for different times.

[0074] The relationship model between the theoretical extinction coefficient and the extinction coefficient is:

[0075]

[0076] Among them, k mod is the theoretical extinction coefficient of the photoresist after exposure for different times, k z is the extinction coefficient, and T is the total number of photoresist film layers.

[0077] S6: Inversely fit the average extinction coefficient and the theoretical extinction coefficient to obtain Dill parameters.

[0078] A deviation function between the average extinction coefficient and the theoretical extinction coefficient is constructed, the initial value of the Dill parameter and the film thickness are input, the Dill parameter is fitted, and the Dill parameter is obtained with the goal of minimizing the deviation function.

[0079] The deviation function of the average extinction coefficient and the theoretical extinction coefficient is:

[0080]

[0081] Among them, k mod (t) is the theoretical extinction coefficient at time t, k ave (t) is the average extinction coefficient at time t, and Q is the number of sampling points. The sampling interval for the exposure measurement experiment should take into account the time required for a single ellipsometer measurement and the exposure light source power. Alternatively, the exposure light intensity can be reduced and the number of sampling points during the exposure process can be increased to improve the fitting accuracy of the subsequent exposure process.

[0082] On the other hand, the present application provides a quasi-dynamic in-situ ellipsometric measurement system for a photoresist exposure process, the system comprising a measurement module, a first model building module, a calculation module, a second model building module, a third model building module, and a second calculation module, wherein:

[0083] Measurement module: used to measure the Mueller matrix information of the photoresist before exposure using a Mueller matrix ellipsometer, expose the photoresist and measure it using the Mueller matrix ellipsometer until the Mueller matrix data remains unchanged, thereby obtaining the measured Mueller matrix of the photoresist;

[0084] The first model building module is used to treat the photoresist as a uniform film, establish a forward optical model, and then obtain the theoretical Mueller matrix;

[0085] Calculation module: used for performing inverse fitting on the measured Mueller matrix and the theoretical Mueller matrix to obtain the ellipsometric parameters, average extinction coefficient and film thickness of the photoresist at different times;

[0086] The second model building module is used to establish a relationship model between the Dill parameter of the photoresist and the optical properties of the photoresist, as well as an exposure model of the photoresist. The optical properties include the extinction coefficient, the exposure light wavelength, the exposure light intensity, and the relative photoacid concentration of the photoresist. The Dill parameter includes the driftable coefficient, the non-driftable coefficient, and the reaction rate constant.

[0087] The third model building module is used to establish a relationship model between the theoretical extinction coefficient and the extinction coefficient, and obtain the theoretical extinction coefficient of the photoresist after exposure for different times;

[0088] The second calculation module is used to perform inverse fitting on the average extinction coefficient and the theoretical extinction coefficient to obtain the Dill parameter.

[0089] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A quasi-dynamic in-situ ellipsometric measurement method for a photoresist exposure process, characterized in that: The method comprises: S1: Using a Mueller matrix ellipsometer to measure the Mueller matrix information of the photoresist before exposure, exposing the photoresist and measuring it using the Mueller matrix ellipsometer until the Mueller matrix data remains unchanged, thereby obtaining the measured Mueller matrix of the photoresist; S2: Considering the photoresist as a uniform film, a forward optical model is established to obtain the theoretical Mueller matrix; S3: performing inverse fitting on the measured Mueller matrix and the theoretical Mueller matrix to obtain the ellipsometric parameters, average extinction coefficient and film thickness of the photoresist at different times; S4: establishing a relationship model between the Dill parameter of the photoresist and the optical properties of the photoresist, as well as an exposure model of the photoresist, wherein the optical properties include the extinction coefficient, the exposure light source wavelength, the exposure light intensity, and the relative photoacid concentration of the photoresist, and the Dill parameter includes the driftable coefficient, the non-driftable coefficient, and the reaction rate constant; S5: establishing a relationship model between a theoretical extinction coefficient and the extinction coefficient to obtain the theoretical extinction coefficient of the photoresist after exposure for different times; S6: Inversely fit the average extinction coefficient and the theoretical extinction coefficient to obtain Dill parameters.

2. The method according to claim 1, characterized in that The relationship model between the Dill parameter of the photoresist and the optical properties of the photoresist in step S4 includes: α=AM+B=4πk / λ Wherein, α is the absorption coefficient, M is the relative photoacid concentration at a certain position in the photoresist, k is the extinction coefficient, λ is the wavelength of the exposure light source, I is the exposure light intensity at the corresponding position, A is the bleachable coefficient, B is the non-bleachable coefficient, C is the reaction rate constant, ΔM is the change in relative photoacid concentration, and Δt is the change time.

3. The method according to claim 1 or 2, characterized in that The exposure model is to divide the photoresist into T layers with uniform thickness and thin film stack.

4. The method according to claim 1 or 2, characterized in that The relationship model between the theoretical extinction coefficient and the extinction coefficient in step S5 is: Among them, k mod is the theoretical extinction coefficient, k z is the extinction coefficient, and T is the total thickness of the photoresist film.

5. The method according to claim 1 or 4, characterized in that Step S6 performs inverse fitting of the average extinction coefficient and the theoretical extinction coefficient as follows: A deviation function between the average extinction coefficient and the theoretical extinction coefficient is constructed, the initial value of the Dill parameter and the film thickness are input, the Dill parameter is fitted, and the Dill parameter is obtained with the goal of minimizing the deviation function.

6. The method according to claim 5, characterized in that The deviation function of the average extinction coefficient and the theoretical extinction coefficient is: Among them, k mod (t) is the theoretical extinction coefficient at time t, k ave (t) is the average extinction coefficient at time t, and Q is the number of sampling points.

7. The method according to claim 1, characterized in that In step S3, the inverse fitting of the measured Mueller matrix and the theoretical Mueller matrix is ​​specifically to construct a deviation function between the measured Mueller matrix and the theoretical Mueller matrix, and to solve the problem with the goal of minimizing the deviation function.

8. The method according to claim 7, characterized in that The deviation function between the measured Mueller matrix and the theoretical Mueller matrix is: Among them, M mod is the theoretical Mueller matrix, M exp is the measured Mueller matrix, λ is the wavelength, and q is the number of wavelengths λ.

9. A quasi-dynamic in-situ ellipsometric measurement system for photoresist exposure process, characterized in that: The system comprises: Measurement module: used to measure the Mueller matrix information of the photoresist before exposure using a Mueller matrix ellipsometer, expose the photoresist and measure it using the Mueller matrix ellipsometer until the Mueller matrix data remains unchanged, thereby obtaining the measured Mueller matrix of the photoresist; The first model building module is used to treat the photoresist as a uniform film, establish a forward optical model, and then obtain the theoretical Mueller matrix; Calculation module: used for performing inverse fitting on the measured Mueller matrix and the theoretical Mueller matrix to obtain the ellipsometric parameters, average extinction coefficient and film thickness of the photoresist at different times; The second model building module is used to establish a relationship model between the Dill parameter of the photoresist and the optical properties of the photoresist, as well as an exposure model of the photoresist. The optical properties include the extinction coefficient, the exposure light wavelength, the exposure light intensity, and the relative photoacid concentration of the photoresist. The Dill parameter includes the driftable coefficient, the non-driftable coefficient, and the reaction rate constant. The third model building module is used to establish a relationship model between the theoretical extinction coefficient and the extinction coefficient, and obtain the theoretical extinction coefficient of the photoresist after exposure for different times; The second calculation module is used to perform inverse fitting on the average extinction coefficient and the theoretical extinction coefficient to obtain the Dill parameter.

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