Wafer detection method and device

Abstract

The embodiment of the invention provides a wafer detection method and device, and the method comprises the steps: providing a to-be-detected wafer which comprises a recessed structure extending from the surface of the wafer to the interior of the wafer; coating a reflection increasing optical film on the surface of the wafer; irradiating the surface of the wafer through an incident light source; detecting a reflected light signal reflected by the inner wall of the sunken structure; and determining whether the inner wall of the sunken structure has a defect structure or not according to the reflected light signal.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor manufacturing technology, and in particular to a wafer inspection method and apparatus. Background Technology

[0002] With the development of semiconductor integrated circuit manufacturing technology, the number of devices contained in integrated circuits is constantly increasing, and the size of the devices is constantly shrinking. The generation of tiny defects often affects the function of semiconductor devices, thus leading to a loss of semiconductor device yield. To improve the yield of semiconductor devices, multiple inspection processes are set up during the manufacturing process to detect defects during manufacturing, further trace the causes of defects, and improve the production process in a timely manner to improve product yield.

[0003] Currently, optical inspection technology is mainly used to detect defects inside wafers. The inspection equipment scans the surface of the wafer at a high speed, and then processes the beam signal reflected back from the wafer surface to obtain defect data. When inspecting internal defects in recessed structures, if the aspect ratio is too large or the aperture is too small, the incident light will be significantly attenuated due to scattering and absorption by the recessed inner wall material. This makes it difficult for the reflected light signal to be transmitted to the inspection equipment, ultimately making it difficult to detect the internal defects of the recessed structure. Summary of the Invention

[0004] In view of this, the present disclosure provides a wafer inspection method and apparatus.

[0005] According to one aspect of the embodiments of this disclosure, a wafer inspection method is provided, comprising: A wafer to be inspected is provided, the wafer including a recessed structure extending from the surface of the wafer into the interior of the wafer; An anti-reflective optical film is coated on the surface of the wafer; The wafer surface is illuminated by an incident light source; Detect the reflected light signal reflected by the inner wall of the recessed structure; Based on the reflected light signal, it is determined whether there is a defect structure on the inner wall of the recessed structure.

[0006] In some embodiments, the method further includes: removing the anti-reflective optical film coated on the wafer surface.

[0007] In some embodiments, removing the anti-reflection optical film coated on the wafer surface includes: The anti-reflective optical film coated on the wafer surface is removed by an ashing process.

[0008] In some embodiments, the anti-reflective optical film covers at least a portion of the sidewalls of the recessed structure; and / or at least a portion of the bottom.

[0009] In some embodiments, determining whether there is a defect structure on the inner wall of the recessed structure based on the reflected light signal includes: Based on the reflected light signal at the bottom of the recessed structure, determine whether there is a defect structure at the bottom of the recessed structure; Based on the reflected light signal from the sidewall of the recessed structure, it can be determined whether there is a defect in the sidewall of the recessed structure.

[0010] In some embodiments, the material of the antireflective optical film includes polyimide and metal-organic framework materials.

[0011] In some embodiments, coating the anti-reflection optical film on the wafer surface includes: coating the anti-reflection optical film on the wafer surface using a spin coating method.

[0012] In some embodiments, the process of coating the anti-reflection optical film on the wafer surface using a spin-coating method includes: The anti-reflective optical film of the target thickness is coated on the wafer surface based on the preset spin coating solution concentration and spin coating process parameters.

[0013] In some embodiments, the target thickness of the antireflective optical film is 1 nm to 1000 nm.

[0014] According to one aspect of the present disclosure, a wafer inspection apparatus is provided to perform any of the wafer inspection methods described herein.

[0015] In this embodiment, an anti-reflective optical film is coated on the wafer surface; the wafer surface is illuminated by an incident light source; the reflected light signal reflected from the inner wall of the recessed structure is detected; and based on the reflected light signal, it is determined whether a defect structure exists on the inner wall of the recessed structure. Thus, by coating the wafer surface with an anti-reflective optical film, more reflected light signals can be detected, thereby improving the detection rate of defects on the wafer surface and within the recessed structure. The anti-reflective optical film coated in this embodiment is a removable film and does not affect subsequent processes or the structure. Attached Figure Description

[0016] Figure 1 A flowchart of a wafer inspection method provided in an embodiment of this disclosure Figure 1 ; Figure 2 The principle of a wafer inspection method provided in this disclosure embodiment Figure 1 ; Figure 3 A flowchart of a wafer inspection method provided in this disclosure embodiment Figure 2 ; Figure 4 The principle of a wafer inspection method provided in this disclosure embodiment Figure 2 ; Figure 5 The principle of a wafer inspection method provided in this disclosure embodiment Figure 3 ; Figure 6 A structural block diagram of a wafer inspection device provided for the implementation of this disclosure. Detailed Implementation

[0017] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0018] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of this disclosure. However, it will be apparent to those skilled in the art that this disclosure may be practiced without one or more of these details. In other instances, to avoid confusion with this disclosure, certain technical features well-known in the art have not been described; that is, not all features of actual embodiments are described herein, nor are well-known functions and structures described in detail.

[0019] To gain a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration only and are not intended to limit the embodiments of this disclosure.

[0020] With the rapid development of semiconductor manufacturing technology, the requirements for manufacturing processes are becoming increasingly stringent, and the semiconductor devices produced are also moving towards miniaturization and precision. Detecting defects inside the wafer during the wafer fabrication process is an important means of improving yield.

[0021] Currently, optical inspection technology is mainly used to detect defects inside wafers. When inspecting defects inside recessed structures, if the aspect ratio is too large or the aperture is too small, the incident light will be significantly attenuated due to scattering and absorption by the material inside the recessed structure. This makes it difficult for the reflected light signal to be transmitted to the inspection equipment, ultimately making it difficult to detect the internal defects of the recessed structure. While electron beam scanning can overcome the above structural limitations, it is limited by slow scanning speed and can usually only be carried out in a sampling mode. This not only restricts production capacity but may also lead to missed detections due to incomplete coverage. At the same time, electron beam equipment is expensive and complex to maintain, which will significantly increase the cost of wafer fabrication.

[0022] Reference Figure 1 As shown in the embodiments of this disclosure, a wafer inspection method is provided, including the following steps: Step S101: Provide a wafer to be inspected, the wafer including a recessed structure extending from the surface of the wafer to the interior of the wafer; Step S102: Coat the surface of the wafer with an anti-reflection optical film; Step S103: Irradiate the wafer surface with an incident light source; Step S104: Detect the reflected light signal reflected by the inner wall of the recessed structure; Step S105: Determine whether there is a defect structure on the inner wall of the recessed structure based on the reflected light signal.

[0023] In this embodiment, an anti-reflective optical film is coated on the wafer surface; the wafer surface is illuminated by an incident light source; the reflected light signal reflected from the inner wall of the recessed structure is detected; and based on the reflected light signal, it is determined whether a defect structure exists on the inner wall of the recessed structure. Thus, by coating the wafer surface with an anti-reflective optical film, more reflected light signals can be detected, thereby improving the detection rate of defects on the wafer surface and within the recessed structure. The anti-reflective optical film coated in this embodiment is a removable film and does not affect subsequent processes or the structure.

[0024] Anti-reflective optical films are functional thin films that enhance the reflection of light of a specific wavelength at the film interface by designing the refractive index and thickness of the film material. By depositing single or multiple thin films on the substrate surface and controlling the refractive index and physical thickness of the films, the incident light is caused to undergo constructive interference at the upper and lower surfaces of the film, thereby superimposing and enhancing the intensity of reflected light while weakening the intensity of transmitted light.

[0025] Reference Figure 2 As shown, in step S101, a wafer 10 to be tested is provided. The wafer 10 here can be a wafer 10 formed in a certain semiconductor manufacturing process. A recessed structure 20 is formed inside the wafer 10. The recessed structure 20 extends from the surface of the wafer 10 to the interior of the wafer 10. The test is performed to detect whether there is a defect structure 30 on the inner wall of the recessed structure 20.

[0026] In this embodiment, the recessed structure 20 includes one or more of the following: contact hole, storage hole, through silicon via (TSV), and channel via.

[0027] Contact holes are vertically inserted into the insulating dielectric layer of a wafer's multilayer wiring structure. One end connects to the semiconductor functional device on the lower layer of the dielectric layer, and the other end connects to the metal interconnect wiring on the upper layer, realizing the electrical connection between the upper metal wiring and the lower semiconductor device. Common defects in contact holes include: voids, bottom residue, hole wall damage, and metal protrusions. The presence of any of these defects in a contact hole will directly affect the quality of the electrical connection and may even lead to local interconnect failure.

[0028] A memory via is a vertically penetrating layer upon layer of stacked memory cells within a wafer. It is filled with conductive material to establish electrical connections between the memory cells, enabling data storage and retrieval. Common defects within memory vias include: thin-film defects on the via walls (uneven film thickness, pinholes, or cracks), bottom residue, and internal voids. The presence of any of these defects directly compromises the electrical properties of the memory cells, thus affecting the accuracy and stability of data storage.

[0029] TSVs (Transient Visor Modules) vertically penetrate the entire wafer, extending from the top to the bottom surface, enabling vertical connections between the front and back circuitry. Common defects within TSVs include: via wall cracks, voids, internal voids, gaps, and surface protrusions. The presence of any of these defects within a TSV can directly compromise the reliability of the vertical interconnects, leading to signal transmission failure between wafers.

[0030] Therefore, detecting defects in the inner wall of the recessed structure is crucial to ensuring the reliability of vertical interconnects within the wafer / chip, the normal implementation of core functions, and product yield and stability.

[0031] Reference Figure 3 and Figure 4 As shown, in some embodiments, step S102, coating an anti-reflection optical film 40 on the surface of wafer 10, may specifically include: An anti-reflective optical film is coated on the surface of a wafer using a spin coating method.

[0032] Specific operational steps may include: Step S201: Clean the wafer surface using a cleaning process; Step S202: Coat the wafer surface with an anti-reflection optical film solution; Step S203: Perform a thermal curing treatment on the anti-reflective optical film solution coated on the wafer surface.

[0033] In this embodiment, in step S201, the surface of wafer 10 is cleaned using a cleaning process, such as dry etching, wet etching, and CMP (Chemical Mechanical Etching). Polishing (chemical mechanical polishing) and other methods are used to remove residues from the surface of wafer 10 and the inner wall of recessed structure 20, preventing residues from affecting the formation of anti-reflective optical film 40 and ensuring that anti-reflective optical film 40 is stably formed on the surface of wafer 10. In step S202, an anti-reflective optical film 40 solution is coated on the surface of wafer 10. Wafer 10 is fixed on a spin coater, and the anti-reflective optical film 40 solution is coated on the surface of wafer 10 through a spin coating process. Wafer 10 is kept at a certain rotation speed, and anti-reflective optical film 40 solution is sprayed onto the surface of wafer 10. The rotation time is set, and the anti-reflective optical film 40 solution is evenly covered on the surface of wafer 10 and the inner wall of recessed structure 20 under the action of centrifugal force. In step S203, the anti-reflective optical film 40 solution on the surface of wafer 10 is subjected to thermal curing treatment to fix the anti-reflective optical film 40 solution into a film on the surface of wafer 10.

[0034] In this embodiment, the reflective optical film 40 is made of polyimide. For recessed structures with excessive aspect ratio or small aperture, polyimide has fluidity and wettability, which allows it to uniformly cover the surface of the wafer 10 and the sidewalls 201 and bottom 202 of the recessed structure 20 during the coating process. No high-temperature environment is required during spin coating, which can avoid thermal damage and stress failure to the recessed structure 20. At the same time, by designing the molecular structure of the polyimide material, its film refractive index can be controlled to achieve matching with different types of recessed structures 20.

[0035] In some embodiments, the reflective optical film material is an organic material, including: polyimide, metal-organic frameworks (MOFs).

[0036] Polyimide is a high-performance polymer with repeating imide rings in its main molecular chain, possessing properties such as high temperature resistance, high mechanical strength, and chemical corrosion resistance. By introducing specific functional groups (such as fluorine atoms or sulfide groups) into the polyimide molecular structure, the material's ability to refract light can be significantly improved, making its refractive index higher than that of the substrate. Based on this property, coating a polyimide film with a specific refractive index onto the substrate surface can effectively enhance light reflection within the target wavelength range, thereby increasing the signal intensity of the reflected light. In addition, polyimide has excellent film-forming properties, allowing for the fabrication of films with smooth and uniform surfaces, significantly reducing light absorption and scattering losses.

[0037] MOFs (Metal-Organic Facility Materials) are a class of porous crystalline materials formed by metal ions / clusters and organic ligands linked by coordination bonds. They possess core characteristics such as tunable pore size, ultra-large specific surface area, and designable structure. By changing the composition, pore size, and guest molecules adsorbed within the pores of MOFs, their refractive index can be precisely and continuously controlled within a certain range. When a MOF film with a refractive index higher than that of air is coated onto a substrate, the interference effect of light at the "air-MOF-substrate" interface can significantly enhance reflected light within a specific wavelength range.

[0038] In step S102, the anti-reflection optical film of the target thickness is coated on the wafer surface based on the preset spin coating solution concentration and spin coating process parameters.

[0039] In this embodiment, the wafer 10 is kept at a preset rotation speed, and a preset concentration of anti-reflective optical film 40 solution is sprayed onto the surface of the wafer 10. A preset rotation time is set, and the anti-reflective optical film 40 solution can form an anti-reflective optical film 40 of the target thickness under the action of centrifugal force and uniformly cover the surface of the wafer 10 and the inner wall of the recessed structure 20.

[0040] In this embodiment, the anti-reflective optical film solution completely covers the sidewalls 201 and bottom 202 of the recessed structure 20.

[0041] In some embodiments, the anti-reflective optical film solution covers at least a portion of the sidewalls and / or at least a portion of the bottom of the recessed structure.

[0042] In some embodiments, the target thickness of the anti-reflective optical film is from 1 nm to 1000 nm. For example, 40 nm, 100 nm, 300 nm, etc. In practical applications, it can be set according to the parameters of the optical components of the testing equipment, such as the light source parameters and the distance between the light source and the wafer under test, so as to achieve a stronger anti-reflective effect.

[0043] In steps S103 to S105, the wafer surface is illuminated by an incident light source; the reflected light signal reflected by the inner wall of the recessed structure is detected; and based on the reflected light signal, it is determined whether there is a defect structure on the inner wall of the recessed structure.

[0044] In this embodiment, the incident light source illuminates the surface of the target wafer 10 and scans the surface of the target wafer 10. By receiving the reflected light signal reflected by the anti-reflection optical film and based on the detection image of the surface of the wafer 10 and the inner wall of the recessed structure 20 formed by the reflected light signal, it is determined whether there is a defect structure 30 on the surface of the wafer 10 and the inner wall of the recessed structure 20.

[0045] Reference Figure 5As shown, in this embodiment, in steps S104 to S105, the incident light source irradiates the anti-reflective optical film 40 coated on the bottom 202 of the recessed structure, generating specular reflection in the normal area of ​​the bottom 202 of the recessed structure and diffuse reflection in the defective structure 30. The intensity of the reflected light signal that generates specular reflection is greater than the intensity of the reflected light signal that generates diffuse reflection. In the detection image, the normal area appears as a high-brightness area, and the defective structure 30 appears as a low-brightness area. The presence of the defective structure 30 in the bottom 202 of the recessed structure 20 is determined by the detection image.

[0046] In this embodiment, coating the inner wall of the recessed structure 20 with an anti-reflective optical film 40 can significantly reduce the probability of incident light being absorbed and scattered by the inner wall material of the recessed structure 20, so that more incident light is reflected by the inner wall of the recessed structure 20 to form an effective reflected light signal, thereby improving the detection rate of defective structures 30 in the inner wall of the recessed structure 20.

[0047] In some embodiments, the incident light source can be adjusted so that it illuminates the sidewall 201 of the recessed structure 20. After the incident light source is reflected by the anti-reflective optical film 40 covering the sidewall 201 of the recessed structure, the reflected light signal is received and a detection image of the sidewall 201 of the recessed structure is formed, thereby determining whether there is a defective structure 30 in the sidewall 201 of the recessed structure 20.

[0048] In some embodiments, a bright field tester can be used as a wafer inspection device 100 to detect whether there are defect structures on the inner wall of the recessed structure inside the wafer.

[0049] A bright-field imaging (BFA) system is an inspection device that utilizes bright-field imaging technology to visualize and observe wafer surface defects and structural features in semiconductor manufacturing. The core principle of BFA system inspection of wafer surface defects is to illuminate the wafer surface with incident light at a specific angle and identify defects by analyzing the intensity difference of reflected light between defective and normal areas. The main types of defects detected include: surface particles, physical damage (scratches, pits, bumps), and thin film defects (uneven thickness, pinholes, peeling).

[0050] Reference Figure 6As shown, the light source system 50 of the bright-field instrument provides an incident light source that illuminates the surface of the sample to be tested, placed on the sample stage 60. In the normal area of ​​the sample surface, after the incident light is irradiated, it follows the law of specular reflection, with most of the light reflected along its original direction and received by the optical acquisition system 70, becoming the "bright" background signal in the detection image. In the defect area of ​​the sample surface, after the incident light is irradiated, the defect area absorbs part of the incident light, and at the same time, the irregular surface of the defect area causes diffuse reflection of the incident light, deviating from the original light path and failing to be received by the optical acquisition system, becoming the "dark" background signal in the image. The imaging system 80 converts the reflected light signal received by the optical acquisition system 70 into a visual image.

[0051] When using a bright-field instrument to detect defects on the inner wall of a recessed structure, if the depth-to-width ratio of the recessed structure is too large or the aperture is too small, the incident light source will reflect off the inner wall of the recessed structure. As the reflected light propagates along the inner wall of the recessed structure, it will be absorbed and scattered multiple times by the material of the inner wall of the recessed structure, resulting in light energy attenuation. As a result, it will be impossible to form an effective scattered light signal to reach the optical acquisition system, making it difficult to detect defects inside the recessed structure.

[0052] In this embodiment, the light source system 50 of the bright field instrument provides an incident light source to illuminate the surface of the wafer 10 placed on the sample stage 60 and scans the surface of the wafer 10. After being reflected by the anti-reflective optical film 40 on the surface of the wafer 10 and the inner wall of the recessed structure 20, an effective reflected light signal is formed and received by the optical acquisition system 70. Then, it is processed by the imaging system 80 to form a detection image of the surface of the wafer 10 and the inner wall of the recessed structure 20. Based on the detection image, it is determined whether there is a defect structure 30 on the surface of the wafer 10 and the inner wall of the recessed structure 20.

[0053] In this embodiment, the light source system of the bright field instrument provides an incident light source to illuminate the anti-reflective optical film 40 coated on the bottom 202 of the recessed structure. Specular reflection is generated in the normal area of ​​the bottom 202 of the recessed structure, and diffuse reflection is generated at the defective structure 30. The intensity of the reflected light signal that generates specular reflection is greater than the intensity of the reflected light signal that generates diffuse reflection. When the imaging system converts the reflected light signal into a visible detection image, the normal area appears as a high-brightness area in the detection image, and the defective structure 30 appears as a low-brightness area. The presence of the defective structure 30 at the bottom 202 of the recessed structure 20 is determined by the detection image.

[0054] In this embodiment, coating the inner wall of the recessed structure 20 with an anti-reflective optical film 40 can significantly reduce the probability of incident light being absorbed and scattered by the inner wall material of the recessed structure 20, so that more incident light is reflected by the inner wall of the recessed structure 20 to form an effective reflected light signal that is received by the optical system, thereby improving the detection rate of defective structures 30 in the inner wall of the recessed structure 20.

[0055] In some embodiments, the illumination angle of the light source is adjusted by the control system so that the incident light source illuminates the sidewall 201 of the recessed structure 20. After being reflected by the anti-reflective optical film 40 of the sidewall 201 of the recessed structure, the reflected light signal is received by the optical acquisition system and then processed by the imaging system to form a detection image of the sidewall 201 of the recessed structure. Based on the detection image, it is determined whether there is a defect structure 30 in the sidewall 201 of the recessed structure 20.

[0056] In some embodiments, the wafer inspection method further includes: removing the anti-reflective optical film coated on the wafer surface.

[0057] In this embodiment, the anti-reflective optical film 40 on the surface of wafer 10 is removed by an ashing process. The active particles in the ashing process gas react chemically with the organic materials, oxidizing and decomposing the organic materials into volatile gaseous products, thereby removing the anti-reflective optical film 40.

[0058] Specifically, the active oxygen particles in the ashing process gas react chemically with the polyimide material, decomposing and oxidizing the polymer chains of the polyimide material to form volatile gaseous products, thereby removing the polyimide film. After the ashing process, wafer 10 is cleaned.

[0059] In this embodiment, the anti-reflective optical film 40 on the surface of wafer 10 is removed by ashing process. The process is simple and gentle, leaves few residues, and will not cause secondary damage to the surface of wafer 10 or the recessed structure 20.

[0060] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure.

[0061] It should be understood that the phrase "an embodiment" or "one embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this disclosure. Therefore, "in one embodiment" or "one embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this disclosure, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this disclosure. The sequence numbers of the above-described embodiments are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0062] The methods disclosed in the several method embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new method embodiments.

[0063] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A wafer inspection method, characterized by, The method comprises: providing a wafer to be detected, the wafer comprising a recessed structure extending from a surface of the wafer to an interior of the wafer; applying a high-refraction optical film on the surface of the wafer; illuminating the surface of the wafer by an incident light source; detecting a reflected light signal reflected by an inner wall of the recessed structure; determining whether the inner wall of the recessed structure has a defect structure according to the reflected light signal.

2. The wafer inspection method of claim 1, wherein The method further comprises:

3. The wafer inspection method of claim 2, wherein removing the high-refraction optical film applied on the surface of the wafer. The removing the high-refraction optical film applied on the surface of the wafer comprises:

4. The wafer inspection method of claim 1, wherein removing the high-refraction optical film applied on the surface of the wafer by a gray ash process. The high-refraction optical film covers at least part of a side wall of the recessed structure; and / or, 5. The wafer inspection method of claim 4, wherein at least part of a bottom. The determining whether the inner wall of the recessed structure has a defect structure according to the reflected light signal comprises: determining whether the bottom of the recessed structure has a defect structure according to a reflected light signal of the bottom of the recessed structure; 6. The wafer inspection method according to any one of claims 1 to 5, wherein determining whether the side wall of the recessed structure has a defect structure according to a reflected light signal of the side wall of the recessed structure.

7. The wafer inspection method of claim 1, wherein A material of the high-refraction optical film comprises polyimide, metal organic framework material.

8. The wafer inspection method of claim 7, wherein, The applying the high-refraction optical film on the surface of the wafer comprises: applying the high-refraction optical film on the surface of the wafer by a spin coating method.

9. The wafer inspection method of claim 8, wherein, The applying the high-refraction optical film on the surface of the wafer by the spin coating method comprises:

10. A wafer inspection apparatus characterized by comprising: applying the high-refraction optical film with a target thickness on the surface of the wafer based on a preset spin coating solution concentration and spin coating process parameters. The target thickness of the high-refraction optical film is 1 nm to 1000 nm. The wafer detection method is executed according to any one of claims 1 to 9.

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