Method for identifying mark with blazed grating structure on substrate

Abstract

The invention discloses two identification methods for a mark with a blazed grating structure on a substrate, and the method comprises the steps: carrying out the photoetching or etching of the blazed grating structure in the mark, carrying out the feature matching through recording the reflection efficiency in a wave band according to the characteristic that the blazed grating structure shines at a specific wavelength, and carrying out the recognition of the mark. The influence of interference factors such as falling dust and impurities on the substrate, photoresist spin coating defects and the like on mark grabbing can be effectively avoided. The accuracy of mark identification can be improved, the blazed grating structure has a unique diffraction efficiency characteristic, and under a specific blazed wavelength, the diffraction efficiency of the grating has a maximum value and forms an obvious difference with an interferent, so that the mark and the interferent can be accurately distinguished, and misjudgment of a visual positioning system is avoided.

Description

Technical Field

[0001] The present invention belongs to the field of micro-nano processing technology, and in particular relates to a method for identifying a mark having a blazed grating structure on a substrate. Background Art

[0002] In the field of micro-nanofabrication, processes such as embossing often require multi-layer overlay to achieve micro-nanoscale overlay accuracy. As a key factor influencing product performance and quality, overlay accuracy places extremely high demands on mark design and recognition. Marker shape and size must be individually designed to enhance recognition and alignment accuracy, ensuring accurate overlay of each layer.

[0003] However, in the actual production process, dust and dirt, photoresist coating defects (such as Figure 1 The appearance characteristics of these interference factors can easily be confused with the mark, causing the visual positioning system to misjudge or even fail to grasp the mark, seriously affecting the accuracy and stability of the overlay process.

[0004] Currently, alignment processes typically use grayscale recognition or contour extraction. However, the presence of these interference factors renders these methods ineffective because they cannot effectively distinguish the subtle differences in grayscale or contour between the mark and the interference object, resulting in reduced overlay accuracy, affecting product quality and production efficiency. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention proposes a method for identifying a mark having a blazed grating structure on a substrate.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] First, the present invention discloses a method for identifying a mark having a blazed grating structure on a substrate, comprising:

[0008] Step S1: etching a blazed grating structure in the marking area of each substrate;

[0009] Step S2: pre-measuring multiple diffraction efficiency standard values of the blazed grating within the reference light source wavelength range, and establishing a light source wavelength-diffraction efficiency standard value database;

[0010] Step S3: loading the substrate to be grasped onto the alignment platform, adjusting the incident angle of the alignment light source to the Littrow angle, and scanning the output wavelength of the alignment light source;

[0011] Step S4: collecting the diffraction efficiency of the marked area in real time and matching it with the diffraction efficiency standard value at the corresponding wavelength in the database;

[0012] Step S5: When the deviation between the collected diffraction efficiency and the standard value of the diffraction efficiency is less than a threshold value, the mark recognition is successful.

[0013] On the basis of the above technical solution, the following improvements can be made:

[0014] As a preferred solution, the reference light source is a tunable light source that can quickly switch between different wavelength bands.

[0015] Second, the present invention discloses another method for identifying a mark having a blazed grating structure on a substrate, characterized by comprising:

[0016] Step S1: etching a blazed grating structure in the marking area of each substrate;

[0017] Step S2: pre-determining a standard value of the diffraction efficiency of the blazed grating at a preset wavelength of a reference light source;

[0018] Step S3: loading the substrate to be grasped onto the alignment platform, adjusting the incident angle of the alignment light source to the Littrow angle, and adjusting the wavelength of the alignment light source to a preset wavelength;

[0019] Step S4: collecting the diffraction efficiency of the marked area in real time and matching it with the diffraction efficiency standard value;

[0020] Step S5: When the deviation between the collected diffraction efficiency and the standard value of the diffraction efficiency is less than a threshold value, the mark recognition is successful.

[0021] As a preferred solution, the alignment light source is a tunable light source that can quickly switch between different wavelength bands.

[0022] As a preferred solution, the blazed grating is composed of a number of asymmetric junction units that are periodically and continuously arranged.

[0023] As a preferred solution, the height of the asymmetric junction unit is 0.5±0.05 μm, and the width is 0.5±0.05 μm.

[0024] As a preferred solution, an annular groove is provided on the periphery of the blazed grating to isolate optical interference from surrounding contaminated areas.

[0025] As a preferred solution, the determination of the diffraction efficiency standard value includes the following:

[0026] The blazed gratings marked on multiple substrates from the same batch are statistically averaged to obtain the standard value of diffraction efficiency corresponding to any wavelength of the reference light source.

[0027] As a preferred solution, the identification method further includes:

[0028] Step S6: After the initial identification of the mark, the marked area is screened for secondary contamination using the trained mark recognition model to eliminate interference from residual particles.

[0029] The present invention discloses a method for identifying marks having blazed grating structures on two substrates. By photolithographically or etching the blazed grating structure within the mark, utilizing the characteristic of blazing at a specific wavelength, and performing feature matching by recording the reflection efficiency within the wavelength band, the method can effectively prevent interference factors such as dust and debris on the substrate and photoresist coating defects from affecting mark capture. The method has the following beneficial effects:

[0030] First, it improves the accuracy of mark recognition. The blazed grating structure has unique diffraction efficiency characteristics. At a specific blazed wavelength, the grating's diffraction efficiency reaches a maximum value, forming a clear difference from interference objects. This allows for precise distinction between marks and interference objects, avoiding misjudgment by the visual positioning system.

[0031] Second, it improves overlay accuracy. Accurate mark recognition and capture provide a reliable foundation for subsequent alignment work, ensuring that multi-layer overlay accuracy reaches the micro-nano level, improving product performance and quality.

[0032] Third, the anti-interference ability of mark recognition is enhanced. Compared with traditional grayscale recognition and contour extraction methods, the method of the present invention is not affected by interference factors such as dirt and defects on the substrate surface, and has greater stability and reliability in complex production environments.

[0033] Fourth, it improves production efficiency, reduces the number of repeated inspections and adjustments caused by mark recognition errors, shortens production cycles, and reduces production costs.

[0034] Fifth, it has a wide range of applicability. It is suitable for overlay processes in various micro-nano processing fields, has good compatibility with the marked materials and substrate types, and can meet the needs of different production scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 A schematic diagram of a grayscale recognition method for identifying marks provided by the prior art;

[0037] Figure 1 Part A in the middle is a glue uniformity defect.

[0038] Figure 2A flow chart of a method for identifying a blazed grating structure mark on a substrate provided by an embodiment of the present invention.

[0039] Figure 3 A schematic structural diagram of a cross mark provided in an embodiment of the present invention.

[0040] Figure 4 A schematic structural diagram of a blazed grating provided in an embodiment of the present invention.

[0041] Among them: 1-blazed grating. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0044] The expression “including” an element is an “open” expression. The “open” expression only means that the corresponding components or steps exist, and should not be interpreted as excluding additional components or steps.

[0045] In order to achieve the purpose of the present invention, in some embodiments of a method for identifying a blazed grating structure mark on a substrate, as Figure 2 As shown, the identification method includes:

[0046] Step S101: Figure 3-4 As shown, a blazed grating structure is etched in the cross-shaped mark area of each substrate;

[0047] Step S102: pre-measuring multiple diffraction efficiency standard values of the blazed grating within the reference light source wavelength range, and establishing a light source wavelength-diffraction efficiency standard value database;

[0048] Step S103: loading the substrate to be grasped onto the alignment platform, adjusting the incident angle of the alignment light source to the Littrow angle, and scanning the output wavelength of the alignment light source;

[0049] Step S104: collecting the diffraction efficiency of the marked area in real time, and matching it with the diffraction efficiency standard value at the corresponding wavelength in the database;

[0050] Step S105: When the deviation between the collected diffraction efficiency and the standard value of the diffraction efficiency is less than a threshold, the mark recognition is successful.

[0051] The special structural design of the blazed grating makes the diffraction efficiency of the grating reach a maximum value at a specific blazing wavelength when the incident light is at the Littrow angle.

[0052] In order to further optimize the implementation effect of the present invention, in some other implementation methods, the remaining characteristic technologies are the same as the above embodiments, except that the reference light source is a tunable light source that can quickly switch between different bands.

[0053] In order to further optimize the implementation effect of the present invention, in some other implementation methods, the remaining characteristic technologies are the same as the above embodiments, except that the blazed grating is composed of a number of asymmetric junction units that are periodically and continuously arranged.

[0054] Furthermore, the asymmetric junction unit may be, but is not limited to, a triangular protrusion with a height h (ie, etching depth) of 0.5±0.05 μm, a width w of 0.5±0.05 μm, and a grating period t of 1±0.1 μm.

[0055] In order to further optimize the implementation effect of the present invention, in some other implementation methods, the remaining characteristic technologies are the same as the above embodiments, except that an annular groove is provided on the periphery of the blazed grating to isolate optical interference from the surrounding contaminated area.

[0056] In order to further optimize the implementation effect of the present invention, in some other implementations, the remaining characteristic technologies are the same as those in the above embodiment, except that the determination of the diffraction efficiency standard value includes the following:

[0057] The blazed gratings marked on multiple substrates from the same batch are statistically averaged to obtain the standard value of diffraction efficiency corresponding to any wavelength of the reference light source.

[0058] In order to further optimize the implementation effect of the present invention, in some other implementations, the remaining feature technologies are the same as those in the above embodiment, except that the recognition method further includes:

[0059] Step S106: After the initial mark recognition, the trained mark recognition model is used to perform a secondary contamination screening on the marked area to eliminate residual particle interference.

[0060] In some other embodiments, the present invention discloses another method for identifying a mark having a blazed grating structure on a substrate, comprising:

[0061] Step S201: etching a blazed grating structure in the cross-shaped mark area of each substrate;

[0062] Step S202: pre-determining a standard value of diffraction efficiency of the blazed grating at a preset wavelength of a reference light source;

[0063] Step S203: loading the substrate to be grasped onto the alignment platform, adjusting the incident angle of the alignment light source to the Littrow angle, and adjusting the wavelength of the alignment light source to a preset wavelength;

[0064] Step S204: collecting the diffraction efficiency of the marked area in real time and matching it with the diffraction efficiency standard value;

[0065] Step S205: When the deviation between the collected diffraction efficiency and the standard value of the diffraction efficiency is less than a threshold, the mark recognition is successful.

[0066] Furthermore, the alignment light source is a tunable light source that can be quickly switched between different wavelength bands.

[0067] The present invention discloses a method for identifying marks having blazed grating structures on two substrates. By photolithographically or etching the blazed grating structure within the mark, utilizing the characteristic of blazing at a specific wavelength, and performing feature matching by recording the reflection efficiency within the wavelength band, the method can effectively prevent interference factors such as dust and debris on the substrate and photoresist coating defects from affecting mark capture. The method has the following beneficial effects:

[0068] First, it improves the accuracy of mark recognition. The blazed grating structure has unique diffraction efficiency characteristics. At a specific blazed wavelength, the grating's diffraction efficiency reaches a maximum value, forming a clear difference from interference objects. This allows for precise distinction between marks and interference objects, avoiding misjudgment by the visual positioning system.

[0069] Second, it improves overlay accuracy. Accurate mark recognition and capture provide a reliable foundation for subsequent alignment work, ensuring that multi-layer overlay accuracy reaches the micro-nano level, improving product performance and quality.

[0070] Third, the anti-interference ability of mark recognition is enhanced. Compared with traditional grayscale recognition and contour extraction methods, the method of the present invention is not affected by interference factors such as dirt and defects on the substrate surface, and has greater stability and reliability in complex production environments.

[0071] Fourth, it improves production efficiency, reduces the number of repeated inspections and adjustments caused by mark recognition errors, shortens production cycles, and reduces production costs.

[0072] Fifth, it has a wide range of applicability. It is suitable for overlay processes in various micro-nano processing fields, has good compatibility with the marked materials and substrate types, and can meet the needs of different production scenarios.

[0073] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for identifying a substrate having a blazed grating structure mark, characterized in that: include: Step S1: etching a blazed grating structure in the marking area of each substrate; Step S2: pre-measuring multiple diffraction efficiency standard values of the blazed grating within the reference light source wavelength range, and establishing a light source wavelength-diffraction efficiency standard value database; Step S3: loading the substrate to be grasped onto the alignment platform, adjusting the incident angle of the alignment light source to the Littrow angle, and scanning the output wavelength of the alignment light source; Step S4: collecting the diffraction efficiency of the marked area in real time and matching it with the standard value of diffraction efficiency at the corresponding wavelength in the database; Step S5: When the deviation between the collected diffraction efficiency and the standard value of the diffraction efficiency is less than a threshold value, the mark recognition is successful.

2. The identification method according to claim 1, characterized in that The reference light source is a tunable light source, which can be quickly switched between different wavelength bands.

3. A method for identifying a substrate having a blazed grating structure mark, characterized in that: include: Step S1: etching a blazed grating structure in the marking area of each substrate; Step S2: pre-determining a standard value of the diffraction efficiency of the blazed grating at a preset wavelength of a reference light source; Step S3: loading the substrate to be grasped onto the alignment platform, adjusting the incident angle of the alignment light source to the Littrow angle, and adjusting the wavelength of the alignment light source to a preset wavelength; Step S4: collecting the diffraction efficiency of the marked area in real time and matching it with the diffraction efficiency standard value; Step S5: When the deviation between the collected diffraction efficiency and the standard value of the diffraction efficiency is less than a threshold value, the mark recognition is successful.

4. The identification method according to claim 3, characterized in that The alignment light source is a tunable light source that can quickly switch between different wavelength bands.

5. The identification method according to any one of claims 1 to 4, characterized in that: The blazed grating is composed of a number of asymmetric junction units that are periodically and continuously arranged.

6. The substrate identification method according to claim 5, characterized in that: The asymmetric junction unit has a height of 0.5±0.05 μm and a width of 0.5±0.05 μm.

7. The identification method according to any one of claims 1 to 4, characterized in that: An annular groove is provided on the periphery of the blazed grating to isolate optical interference from surrounding contaminated areas.

8. The identification method according to any one of claims 1 to 4, characterized in that: The determination of the diffraction efficiency standard value includes the following contents: The blazed gratings marked on multiple substrates from the same batch are statistically averaged to obtain the standard value of diffraction efficiency corresponding to any wavelength of the reference light source.

9. The identification method according to any one of claims 1 to 4, characterized in that: The identification method further includes: Step S6: After the initial identification of the mark, the marked area is screened for secondary contamination using the trained mark recognition model to eliminate interference from residual particles.

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