A method for detecting the coating condition of a photoresist film.

Abstract

This invention provides a method for detecting the coating condition of a photoresist film layer, relating to the field of semiconductor technology. The method includes: providing a wafer and coating the surface of the wafer with a photoresist film layer of a predetermined thickness; dividing the wafer into multiple exposure areas; irradiating detection light onto the photoresist film layer in each of the multiple exposure areas and detecting the diffraction intensity on the surface of the photoresist film layer; determining whether the photoresist film layer in the multiple exposure areas meets the predetermined requirements based on the diffraction intensity in the exposure areas; if the thickness of the photoresist film layer in all exposure areas meets the predetermined requirements, proceeding to the next process step; if the predetermined requirements are not met, removing the photoresist film layer. This invention provides a high detection accuracy and can effectively improve the yield of semiconductor devices.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for detecting the coating condition of a photoresist film. Background Technology

[0002] As a core process in semiconductor device fabrication, photolithography directly determines the precision of the lithographic pattern and the stability of the process by ensuring the uniformity of the photoresist coating. During the photoresist coating process, due to inherent limitations, it is difficult to maintain a uniform photoresist film thickness. Even excluding the influence of the preceding thin film, the uneven film thickness caused by the preceding process alone can lead to linewidth fluctuations and pattern defects under defocus conditions, significantly compressing the lithography process window and reducing process tolerance and product yield. Summary of the Invention

[0003] This invention provides a method for detecting the coating condition of a photoresist film layer, so as to improve photolithography accuracy.

[0004] The present invention provides a method for detecting the coating condition of a photoresist film, comprising: A wafer is provided, and a photoresist film layer of a predetermined thickness is coated on the surface of the wafer; The wafer is divided into multiple exposure areas; Detection light is radiated onto the photoresist film layers in multiple exposure areas respectively, and the intensity of diffracted light on the surface of the photoresist film layer is detected. The photoresist film layers in the multiple exposure areas are determined based on the diffraction light intensity within the exposure area to determine whether they meet the set requirements. If the thickness of the photoresist film layer in the exposed area meets the set requirements, then proceed to the next process step; If the set requirements are not met, the photoresist film layer will be removed.

[0005] In one embodiment of the present invention, the photoresist film layer is judged to meet the set requirements based on the correspondence between the diffraction light intensity and the thickness of the photoresist film layer. The correspondence between the diffraction light intensity and the thickness of the photoresist film layer is I=K×H, where I is the diffraction light intensity, K is the calibration coefficient, and H is the thickness of the photoresist film layer.

[0006] In one embodiment of the present invention, determining whether the photoresist film layers in the plurality of exposure areas meet the set requirements based on the diffraction light intensity within the exposure area includes: Collect the diffraction light intensities I1 and I2 at any two locations within the same exposure area, and denote the corresponding photoresist film thicknesses as H1 and H2, respectively. Based on the relationship between the diffraction intensity and the thickness of the photoresist film, calculate the sum of the heights at the two locations: H1 + H2 = (I1 + I2) / K. If the difference between the value of H1+H2 and twice the preset thickness exceeds a preset threshold, it is determined that the photoresist film layer does not meet the set requirements; otherwise, it meets the set requirements.

[0007] In one embodiment of the present invention, the calibration coefficient K is determined by the following method: Take a measuring piece with a known thickness, the thickness of which is H0; The measuring device emits detection light, and the diffracted light intensity I0 corresponding to the measuring device is collected; The calibration coefficient K is calculated based on the measured diffraction intensity I0 and thickness H0. The formula for calculating the calibration coefficient K is K=I0 / H0.

[0008] In one embodiment of the present invention, if the thicknesses all meet the set requirements, then before proceeding to the next process step, the detection method further includes obtaining a thickness distribution map of the photoresist film layer.

[0009] In one embodiment of the present invention, removing the photoresist film layer includes: The photoresist film layer is subjected to full exposure processing; After the full exposure process, the photoresist film layer is developed.

[0010] In one embodiment of the present invention, when radiating detection light to the photoresist film layer of the plurality of exposure areas and detecting the diffraction intensity on the surface of the photoresist film layer, the whole-domain optical image of the photoresist film layer is acquired by the image acquisition unit, the image is divided into the smallest pixel unit, and optical features are extracted pixel by pixel.

[0011] In one embodiment of the present invention, coating the surface of the wafer with a photoresist film layer of a predetermined thickness includes: The process parameters are specified based on the parameters of the wafer and the preset thickness; According to the process parameters, photoresist is sprayed onto the center of the wafer and the wafer is rotated at a preset speed to form the photoresist film layer.

[0012] In one embodiment of the present invention, before radiating detection light to the photoresist film layer of the plurality of exposure areas, the detection method further includes a first baking process for the photoresist film layer.

[0013] In one embodiment of the present invention, after the photoresist film layer is fully exposed and before the photoresist film layer is developed, the detection method further includes a second baking process for the photoresist film layer.

[0014] The beneficial effects of this invention are as follows: The method for detecting the coating condition of the photoresist film layer proposed in this invention involves forming a photoresist film layer on a wafer, dividing the wafer into multiple exposure areas, and detecting whether the photoresist film layer in each exposure area meets the set requirements. If it does, the next process step is performed; otherwise, the photoresist layer is removed. An unexpected benefit of this invention is that by detecting the flatness of the photoresist film layer within the exposure area, the detection accuracy of the photoresist film layer can be improved, thereby increasing the yield. Furthermore, improving the flatness of the photoresist film layer can also improve the uniformity of the gap between adjacent exposure areas, expanding the etching process window. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0016] In the attached diagram: Figure 1 It is the imaging microstructure under different focal length conditions in the existing technology; Figure 2 This is a thickness distribution diagram of the photoresist layer in existing technology; Figure 3 This is a flowchart of the detection process for photoresist film coating provided in one embodiment of the present invention; Figure 4 This refers to a wafer provided in one embodiment of the present invention; Figure 5 This is a schematic diagram of the formation of a photoresist film layer provided in one embodiment of the present invention; Figure 6 This is a schematic diagram of the first baking process of the photoresist film layer provided in one embodiment of the present invention; Figure 7 This is a schematic diagram of radiating detection light onto a photoresist film layer according to an embodiment of the present invention; Figure 8 This is a schematic diagram of a photoresist film layer being exposed to full light transmittance according to an embodiment of the present invention; Figure 9 This is a schematic diagram of a second baking process for a photoresist film layer provided in one embodiment of the present invention; Figure 10 This is a schematic diagram of a photoresist film layer undergoing full development processing according to an embodiment of the present invention.

[0017] The attached figures are labeled as follows: 100, wafer; 110, substrate; 200, photoresist film layer. Detailed Implementation

[0018] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0019] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0020] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0021] In this document, when referring to numerical ranges, unless otherwise specified, the distribution of selectable values ​​within a numerical range is considered continuous, including the two endpoints of the range (i.e., the minimum and maximum values), and every value between these two endpoints. When multiple numerical ranges are provided to describe a feature or property, these numerical ranges can be combined.

[0022] While existing conventional technologies offer numerous solutions to improve film thickness uniformity by optimizing photoresist coating parameters, maintaining absolute uniformity in the photoresist layer is difficult due to limitations in the photoresist layer coating process. During photolithography, the lens must be precisely focused. If the photoresist surface is uneven, some areas will defocus during wafer movement and exposure, further degrading the clarity of the circuit pattern or causing the linewidth (the gap between adjacent exposure areas) to be too large or too small, potentially leading to pattern defects. For example... Figure 1 As shown, Figure 1 Imaging of the Vertical Interconnect Access (VIA) layer under different focal length conditions in the existing 28-nanometer process node. Figure 1 The green box corresponds to a linewidth with an appropriate size, the red box corresponds to a linewidth with an inappropriate size, and the blue box corresponds to the etching process window. From Figure 1 As can be seen, uneven photoresist layer thickness affects the linewidth, further reducing the etching process window.

[0023] However, existing conventional film thickness measurement methods cannot effectively measure the film thickness within the exposed area, such as creating a thickness distribution map of the photoresist layer (e.g., ...). Figure 2 As shown, for example, the average thickness (Avg), the range of thickness fluctuation around its average value (3Sig), and the thickness difference between the thickest and thinnest points (Rng) of the photoresist layer are evaluated. Therefore, the accuracy of measuring the thickness of the photoresist film layer is low. When the thickness difference within the exposure area is large, it cannot be accurately detected, affecting subsequent processes. Therefore, this invention provides a method for detecting the coating condition of the photoresist film layer on the wafer surface to improve the measurement accuracy of the photoresist layer thickness.

[0024] Please see Figures 3 to 10 As shown, the method for detecting the coating condition of the photoresist film layer 200 on the surface of wafer 100 provided by the present invention includes: S1, Provide Figure 4 The wafer 100 shown is coated with a coating such as... Figure 5 The photoresist film layer 200 with the preset thickness is shown; S2. Divide wafer 100 into multiple exposure areas; S3, such as Figure 7 As shown, detection light is radiated onto the photoresist film layer 200 in multiple exposure areas, and the intensity of diffracted light on the surface of the photoresist film layer 200 is detected. S4. Determine whether the photoresist film layer 200 in multiple exposure areas meets the set requirements based on the diffraction light intensity within the exposure area. S5. If the thickness of the photoresist film layer 200 in the exposed area meets the set requirements, proceed to the next process step. S6, such as Figures 8 to 10 As shown, if the set requirements are not met, the photoresist film layer 200 will be removed.

[0025] Please see Figure 4As shown, in step S2 of the present invention, exemplarily, wafer 100 includes a substrate 110 and a pre-structure formed on the surface of substrate 110, the surface of wafer 100 being, for example, a plane. Substrate 110 can be any material suitable for forming a semiconductor structure, such as undoped single-crystal silicon, doped single-crystal silicon, silicon-on-insulator (SOI), silicon-on-insulator stacked (SSOI), silicon-on-insulator stacked (S-SiGeOI), silicon-on-insulator (SiGeOI), and germanium-on-insulator (GeOI), etc. The present invention does not limit the specific material and thickness of wafer 100, and wafer 100 can be a P-doped semiconductor substrate 110 or an N-doped semiconductor substrate 110; the doping type of the impurity can be flexibly set according to the semiconductor structure to be formed. In some embodiments, wafer 100 may not include the pre-structure, and the structure of wafer 100 is determined according to the application scenario of the photolithography process.

[0026] Please see Figure 5 As shown, in one embodiment of the present invention, the process of coating a photoresist film layer 200 of a preset thickness on the surface of wafer 100 is as follows: First, based on the wafer 100's own parameters (e.g., wafer 100 size, wafer 100 material, surface flatness, previous thin film structure and thickness), combined with the preset thickness of the photoresist film layer 200, the process parameters for photoresist coating are reasonably specified. Process parameters include, for example, the amount of photoresist sprayed, spraying pressure, preset rotation speed, rotational acceleration, and rotational duration, ensuring that each process parameter is compatible with the wafer 100's own characteristics and the preset thickness of the photoresist film layer 200, thereby improving the uniformity of the photoresist film layer 200 and further improving the surface flatness of the photoresist film layer 200. Subsequently, according to the above process parameters, photoresist is precisely sprayed at the spraying center of wafer 100, ensuring that the initial spraying position of the photoresist is accurate and the spraying amount is uniform. Single spraying or multiple spraying can be used. After spraying, the wafer 100 is rotated at a preset speed. The resulting centrifugal force drives the photoresist sprayed at the center of the wafer 100 to spread evenly to the edges, ultimately forming a photoresist film layer 200 on the surface of the wafer 100. This coating method can effectively reduce uneven film thickness caused by improper coating processes, further helping to improve the stability of the photolithography process window. The type of photoresist material is not limited; it can be a common positive photoresist material or a negative photoresist material. In this embodiment, the photoresist material is, for example, a positive photoresist material.

[0027] Please see Figure 6As shown, in one embodiment of the present invention, after forming the photoresist film layer 200, the detection method further includes a first baking process on the photoresist film layer 200. The first baking process, such as low-temperature heating, can effectively remove the solvent in the photoresist film layer 200, and the low-temperature heating allows the solvent to evaporate slowly, reducing defects such as bubbles and pinholes in the photoresist film layer 200. In addition, the viscosity of the photoresist is moderately reduced, and the photoresist film layer 200 tends to flatten through slight flow, improving the uniformity of film thickness. Gentle heating also stabilizes the photosensitizer, resin, and other components in the photoresist, preventing abnormal chemical reactions during subsequent exposure, ensuring the accuracy and integrity of the pattern after exposure of the photoresist film layer 200, and improving process yield.

[0028] In step S2 of this invention, after the photoresist film layer 200 undergoes a first baking process, the wafer 100 is divided into multiple exposure areas. First, the division criteria for the exposure areas are determined based on the design specifications of the semiconductor device, the technical parameters of the photolithography exposure system (e.g., the size of the exposure field of view, the exposure resolution, alignment accuracy, etc.), and the actual size of the wafer 100. Then, the entire wafer 100 is divided into multiple independent exposure areas (shots) according to the division criteria. The size and shape of each exposure area are precisely matched to the exposure field of view of the exposure system, ensuring that subsequent exposure processes can accurately expose individual exposure areas, meeting the pattern accuracy requirements of the semiconductor device design. A certain width is reserved between adjacent exposure areas as an isolation area when dividing the exposure areas. The width of the isolation area is reasonably set according to the size of the wafer 100, the exposure field of view, and the layout of the semiconductor device to avoid pattern overlap and edge interference problems between adjacent exposure areas in subsequent exposure, development, and other processes, ensuring the independence and integrity of each exposure area. After the division is completed, each exposure area is marked with a positioning mark. The mark position is set, for example, within an isolation area, so as not to affect the effective pattern area of ​​the exposure area. This facilitates quick alignment of each exposure area in subsequent exposure processes, improving exposure efficiency and alignment accuracy. In this invention, dividing the wafer 100 into multiple exposure areas can also be done before forming the photoresist film layer 200.

[0029] Please see Figure 7As shown, in step S2 of this invention, an optical detection device is used to radiate detection light to multiple exposure areas. The detection light is incident at different detection positions within each exposure area at a preset incident angle. Simultaneously, the diffraction intensity at different detection positions within each exposure area is acquired. For example, local intensity signals are calculated based on pixel-level image analysis. This involves converting the collected global diffraction light signal of the photoresist film layer 200 surface into an optical image, and then using the smallest independent unit pixel of the image as the core calculation unit. The light intensity signal (i.e., diffraction intensity data) at the corresponding local position is extracted and calculated pixel by pixel, achieving precise quantification and positioning of the local intensity signal, thus enabling blind-zone-free local intensity detection and calculation across the entire exposure area. By partitioning each exposure area and performing point-by-point light radiation and diffraction intensity detection, the global, multi-region, and multi-position diffraction intensity distribution information of the photoresist film layer 200 surface can be obtained. This provides raw optical detection data for subsequent film thickness calculation, defect identification, and process parameter compensation, thereby achieving accurate characterization of the process state of each exposure area.

[0030] In step S4 of this invention, for example, it is determined whether the photoresist film layer 200 meets the set requirements based on the correspondence between diffraction light intensity and the thickness of the photoresist film layer 200. The correspondence between diffraction light intensity and the thickness of the photoresist film layer 200 is I=K×H, where I is the diffraction light intensity, K is the calibration coefficient, and H is the thickness of the photoresist film layer 200. Specifically, the diffraction light intensities I1 and I2 at any two positions in the same exposure area are collected, and their corresponding heights are recorded as H1 and H2, respectively. Based on the correspondence between diffraction light intensity and the thickness of the photoresist film layer 200, the sum of the heights at the two positions is calculated as H1+H2=(I1+I2) / K. If the difference between the value of H1+H2 and twice the preset thickness exceeds a preset threshold, it is determined that the photoresist film layer 200 does not meet the set requirements; otherwise, it meets the set requirements. The calibration coefficient K is determined as follows: A measurement piece with a known thickness, H0, is selected; detection light is emitted onto the measurement piece, and the corresponding diffraction intensity I0 is collected; the calibration coefficient K is calculated based on the measured diffraction intensity I0 and the thickness H0, using the formula K = I0 / H0. No preset threshold is imposed here; it is adjusted according to the requirements of the semiconductor device. Simultaneously, two locations within the exposure area are detected to evaluate the flatness of the photoresist film layer 200.

[0031] In some embodiments, if the thickness of the photoresist film layer 200 in the exposed area meets the set requirements, the detection method further includes obtaining a thickness distribution map of the photoresist film layer 200 before proceeding to the next process step. Specifically, after obtaining the thickness of the photoresist film layer 200 at various locations on the surface of the wafer 100, a thickness distribution map of the photoresist film layer 200 is plotted, and the thickness data and location coordinates of the photoresist film layer 200 at each location are associated and input into a database. The thickness distribution map of the photoresist film layer 200 includes, for example, the average value, three times the standard deviation (3σ), and range information of the thickness of the photoresist film layer 200. In this invention, the three times standard deviation is used to evaluate the fluctuation range of the thickness value around its average value, and the range represents the difference between the maximum and minimum values ​​of the thickness of the photoresist film layer 200 on the same wafer 100. Both the three times standard deviation and the range can be used to evaluate the flatness of the photoresist film layer 200. Analyzing the thickness distribution map of photoresist film layer 200 allows for further inspection of its flatness, improving inspection standards and preventing situations where one inspection point exceeds the preset thickness of photoresist film layer 200, and the other exceeds the preset thickness. Even if the difference between the value of H1+H2 and twice the preset thickness does not exceed the preset threshold, the flatness of photoresist film layer 200 still fails to meet the usage requirements. If the photoresist film layer 200 in any exposure area fails to meet the set requirements based on the diffraction light intensity at each location within the exposure area, then there is no need to analyze the thickness distribution map of photoresist film layer 200.

[0032] In step S5 of this invention, if the thickness of the photoresist film layer 200 meets the set requirements, and the analysis of the thickness distribution map of the photoresist film layer 200 also meets the requirements, then the next process step is performed, which is to expose the photoresist film layer 200. For example, a suitable photomask is selected according to the requirements of the target semiconductor device, the photomask is aligned with the pattern on the wafer 100, and the light source shines through the photomask onto the photoresist film layer 200 to form a latent image.

[0033] Please see Figure 8As shown, in step S6 of this invention, if the thickness of the photoresist film layer 200 does not meet the set requirements, the entire photoresist film layer 200 is completely removed. For example, the photoresist film layer 200 is subjected to full exposure. For instance, the wafer stage of the exposure machine is switched to a fully transparent dummy photomask. Full-transparent virtual illumination allows light to completely penetrate and irradiate the surface of the photoresist film layer 200, ensuring that all photoresist film layers 200 on the surface of the wafer 100 are fully developed during subsequent development, thus completely removing the entire photoresist film layer 200. The full-transparent virtual illumination process uses a purely optical irradiation method, eliminating the need for chemical reagents (such as wet cleaning etching solutions) and high-temperature ashing treatment. This reduces the corrosive damage of chemical reagents to the semiconductor substrate 110 and the previous thin film structure, while avoiding problems such as substrate 110 deformation and film peeling caused by high temperatures, thus minimizing the impact on subsequent recoating of the photoresist film layer 200 and other fabrication processes. Meanwhile, the fully transparent virtual illumination can achieve uniform illumination across the entire surface of wafer 100, ensuring that all photoresist on wafer 100 can be uniformly removed, avoiding problems such as incomplete removal or excessive residue in certain areas. In addition, the fully transparent virtual photomask exposure process is time-saving and easy to operate, and can quickly complete photoresist removal. Compared with the complex process of traditional wet cleaning and ashing, it can significantly shorten the process cycle and improve production efficiency.

[0034] Please see Figure 9 As shown, in one embodiment of the present invention, after the full exposure of the photoresist film layer 200, the detection method further includes a second baking process for the photoresist film layer 200. Exposure itself does not directly change the solubility of the photoresist film layer 200, but rather generates photoacid as a catalyst. Baking after exposure provides energy, allowing the photoacid to diffuse within the photoresist film layer 200 and undergo a catalytic deprotection reaction with the surrounding resin. Exemplarily, when the photoresist film layer 200 is a positive photoresist material, this reaction makes the exposed area highly soluble in the developer.

[0035] Please see Figure 10 As shown, in one embodiment of the present invention, after the photoresist film layer 200 undergoes a second baking process, the photoresist film layer 200 is then developed. For example, a developing solution is sprayed onto the surface of the photoresist film layer 200 to dissolve the exposed photoresist film layer 200 and completely remove it.

[0036] In summary, the photoresist film coating detection method proposed in this invention involves forming a photoresist film layer on a wafer, dividing the wafer into multiple exposure areas, and detecting whether the photoresist film layer in each exposure area meets the set requirements. If it does, the next process step is performed; otherwise, the photoresist layer is removed. An unexpected benefit of this invention is that by detecting the flatness of the photoresist film layer within the exposure area, the detection accuracy of the photoresist film can be improved, thus increasing the yield. Furthermore, improving the flatness of the photoresist film layer can also improve the uniformity of the gap between adjacent exposure areas, expanding the etching process window.

[0037] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for detecting the coating condition of a photoresist film, characterized in that, include: A wafer is provided, and a photoresist film layer of a predetermined thickness is coated on the surface of the wafer; The wafer is divided into multiple exposure areas; Detection light is radiated onto the photoresist film layers in multiple exposure areas respectively, and the intensity of diffracted light on the surface of the photoresist film layers is detected. The photoresist film layer in the multiple exposure areas is determined based on the diffraction light intensity in the exposure area to determine whether it meets the set requirements. The relationship between the diffraction light intensity and the thickness of the photoresist film layer is I=K×H, where I is the diffraction light intensity, K is the calibration coefficient, and H is the thickness of the photoresist film layer. If the thickness of the photoresist film layer in the exposed area meets the set requirements, then proceed to the next process step; If the set requirements are not met, the photoresist film layer shall be removed; The method of determining whether the photoresist film layers in multiple exposure areas meet the set requirements based on the diffraction light intensity within the exposure area includes: Collect the diffraction light intensities I1 and I2 at any two locations within the same exposure area, and denote the corresponding photoresist film thicknesses as H1 and H2, respectively. Based on the relationship between the diffraction intensity and the thickness of the photoresist film, calculate the sum of the heights at the two locations: H1 + H2 = (I1 + I2) / K. If the difference between the value of H1+H2 and twice the preset thickness exceeds a preset threshold, it is determined that the photoresist film layer does not meet the set requirements; otherwise, it meets the set requirements.

2. The detection method according to claim 1, characterized in that, The calibration coefficient K is determined by the following method: Take a measuring piece with a known thickness, the thickness of which is H0; The measuring device emits detection light, and the diffracted light intensity I0 corresponding to the measuring device is collected; The calibration coefficient K is calculated based on the measured diffraction intensity I0 and thickness H0. The formula for calculating the calibration coefficient K is K=I0 / H0.

3. The detection method according to claim 1, characterized in that, If the thickness of the photoresist film layer in the exposed area meets the set requirements, the detection method further includes obtaining a thickness distribution map of the photoresist film layer before proceeding to the next process step.

4. The detection method according to claim 1, characterized in that, Removing the photoresist film layer includes: The photoresist film layer is subjected to full exposure processing; After the full exposure process, the photoresist film layer is developed.

5. The detection method according to claim 1, characterized in that, When radiating detection light to the photoresist film layer in multiple exposure areas and detecting the intensity of diffracted light on the surface of the photoresist film layer, the image acquisition unit acquires a global optical image of the photoresist film layer, and the image is divided into the smallest pixel unit to extract optical features pixel by pixel.

6. The detection method according to claim 1, characterized in that, Coating a photoresist film layer of a predetermined thickness onto the surface of the wafer includes: The process parameters are specified based on the parameters of the wafer and the preset thickness; According to the process parameters, photoresist is sprayed onto the center of the wafer and the wafer is rotated at a preset speed to form the photoresist film layer.

7. The detection method according to claim 1, characterized in that, Before radiating detection light onto the photoresist film layers in the multiple exposure areas, the detection method further includes a first baking process on the photoresist film layers.

8. The detection method according to claim 4, characterized in that, After the photoresist film layer is fully exposed and before the photoresist film layer is developed, the detection method further includes a second baking process for the photoresist film layer.

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