Angle encoder based on silicon-based magnetic pole array structure and preparation method thereof

Abstract

The invention provides an angle encoder based on a silicon-based magnetic pole array structure and a preparation method thereof, and relates to the technical field of angle encoders, the angle encoder comprises a silicon substrate, a magnetic alloy wire and a non-photosensitive polyimide covering layer; the center of the silicon substrate is provided with a round hole matched with a driving rotating shaft of the angle encoder; a plurality of radial grooves are formed in the silicon substrate with the round hole as the center, a silicon-based magnetic pole array structure is formed, and the distances between the adjacent grooves are equal; a magnetic alloy wire is embedded in the groove; the silicon substrate is covered with a non-photosensitive polyimide covering layer, and the non-photosensitive polyimide covering layer is used for wrapping the magnetic alloy wires and filling the grooves; when the angle encoder drives the rotating shaft to drive the silicon substrate to rotate, a radial magnetic pole structure formed by the silicon substrate provided with the magnetic alloy wires and the non-photosensitive polyimide covering layer provides periodic uniform magnetic field distribution so as to carry out angle detection. Machining errors and structural deviation are remarkably reduced, and the angle measurement precision is improved.

Description

Technical Field

[0001] This invention relates to the field of angle encoder technology, and in particular to an angle encoder based on a silicon-based magnetic pole array structure and its fabrication method. Background Technology

[0002] Angle encoders, as core components for rotary position detection, are widely used in industrial automation, robotics, motor control, and automotive electronics. Traditional magnetic encoders typically consist of a magnetic code disk and a magnetic sensor. The code disk has multiple magnetic poles, and the sensor detects changes in the magnetic field during rotation to read angle information.

[0003] Currently, most common magnetic encoders employ mechanical processing methods to fabricate magnetic pole structures, such as cutting, stamping, laser etching, or magnetic colloid coating. These methods have significant limitations in terms of processing accuracy, consistency control, and mass production. For example, mechanical processing struggles to achieve micron-level magnetic pole position control, and the magnetic pole arrangement is constrained by tool size and thermal deformation errors. Furthermore, the numerous processing steps result in poor reliability and repeatability, making it difficult to meet the growing demand for high-precision, miniaturized angle sensing modules.

[0004] In summary, the existing angle encoders suffer from insufficient precision in the fabrication of their magnetic pole structures, resulting in a significant difference between the structural dimensions and the target structural dimensions, which in turn leads to excessive angle measurement errors. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide an angle encoder based on a silicon-based magnetic pole array structure, which can solve the technical problem that the magnetic pole structure of the existing angle encoder has insufficient manufacturing accuracy, and the structural size is too different from the target structural size, thus leading to excessive angle measurement error.

[0006] In a first aspect, an angle encoder based on a silicon-based magnetic pole array structure is proposed, comprising: a silicon substrate, a magnetic alloy wire, and a non-photosensitive polyimide coating layer; A circular hole matching the drive shaft of the angle encoder is formed in the center of the silicon substrate; Multiple radial grooves are formed on a silicon substrate with a circular hole as the center, forming a silicon-based magnetic pole array structure, wherein the spacing between adjacent grooves is equal; A magnetic alloy wire is embedded in the groove; A non-photosensitive polyimide coating is applied to a silicon substrate, wherein the non-photosensitive polyimide coating is used to wrap each magnetic alloy wire and fill each groove; When the angle encoder drives the shaft to rotate the silicon substrate, the radial magnetic pole structure formed by the silicon substrate, which is covered with magnetic alloy wires and a non-photosensitive polyimide coating, provides a periodic and uniform magnetic field distribution for angle detection.

[0007] A second aspect of this invention provides a method for fabricating an angle encoder based on a silicon-based magnetic pole array structure, comprising: S1: Pre-treatment of the silicon substrate; S2: A groove mask is fabricated on a pretreated silicon substrate using a patterning process; S3: Dry etching is performed on the silicon substrate with the groove mask to obtain the groove; S4: Magnetic alloy wire is embedded in the groove; S5: A non-photosensitive polyimide capping layer is formed on a silicon substrate with embedded magnetic alloy wires; S6: Using laser drilling technology, a circular hole is obtained by ablation in the central region of a silicon substrate with a non-photosensitive polyimide coating, thus obtaining an angle encoder.

[0008] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: In this embodiment of the invention, an angle encoder based on a silicon-based magnetic pole array structure constructs multiple equally spaced radial grooves on the outer edge of a silicon substrate using photolithography. High-precision photolithography and plasma etching technologies are employed to achieve precise control of the magnetic pole positions, ensuring the uniformity of the magnetic pole arrangement. After embedding filamentous permalloy magnetic material into the grooves, a stable and uniformly distributed radial magnetic pole array is formed. This array is further encapsulated and fixed by a non-photosensitive polyimide coating, which not only improves the mechanical stability of the structure but also enhances its environmental adaptability. This design can provide a highly consistent periodic magnetic field signal to the magnetic sensor during rotation. Compared to traditional machined magnetic pole code disk structures, it significantly reduces processing errors and structural deviations, improving angle measurement accuracy, repeatability, and overall manufacturing yield, making it particularly suitable for high-precision angle detection scenarios. Attached Figure Description

[0009] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0010] Figure 1 This is a schematic diagram of an angle encoder based on a silicon-based magnetic pole array structure provided in an embodiment of the present invention; Figure 2This is a schematic diagram of an angle encoder embedded in a stator mold according to an embodiment of the present invention; Figure 3 This is a schematic flowchart of a method for fabricating an angle encoder based on a silicon-based magnetic pole array structure, provided by an embodiment of the present invention.

[0011] 1. Silicon substrate; 2. Groove; 3. Magnetic alloy wire; 4. Non-photosensitive polyimide cover layer; 5. Circular hole; 6. Stator mold; 7. Magnetic sensor; 8. Magnet; 9. Ring plate; 10. Embedding groove. Detailed Implementation

[0012] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0013] The angle encoder based on a silicon-based magnetic pole array structure provided in this invention will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0014] Reference manual attached Figure 1 The diagram shows a schematic of an angle encoder based on a silicon-based magnetic pole array structure provided by an embodiment of the present invention.

[0015] This invention provides an angle encoder based on a silicon-based magnetic pole array structure, comprising: a silicon substrate, magnetic alloy wires, and a non-photosensitive polyimide cover layer. A circular hole matching the drive shaft of the angle encoder is formed at the center of the silicon substrate. Multiple radial grooves are formed on the silicon substrate around the circular hole, forming a silicon-based magnetic pole array structure, wherein the spacing between adjacent grooves is equal. Magnetic alloy wires are embedded in the grooves. A non-photosensitive polyimide cover layer is applied to the silicon substrate, which wraps around each magnetic alloy wire and fills each groove. When the drive shaft of the angle encoder rotates the silicon substrate, the radial magnetic pole structure formed by the silicon substrate with the magnetic alloy wires and the non-photosensitive polyimide cover layer provides a periodic, uniform magnetic field distribution for angle detection.

[0016] The silicon substrate serves as the base for the angle encoder, providing structural support and a stable physical foundation. Silicon possesses excellent mechanical properties and micro / nano fabrication capabilities, making it widely used in microelectromechanical systems (MEMS). Magnetic alloy wires, such as permalloy wire, are used to form magnetic poles on the silicon substrate. These wires are embedded in grooves etched into the silicon substrate, forming the core of the magnetic poles and generating periodic magnetic field changes during rotation. A non-photosensitive polyimide capping layer covers the surface of the silicon substrate, encapsulating the magnetic alloy wires and filling the grooves, protecting them while providing additional stability and isolation for the structure. A circular hole is located at the center of the silicon substrate to match the drive shaft, ensuring the angle encoder rotates with the shaft. Multiple radial grooves, centered on a single point, are formed on the outer edge of the silicon substrate. These uniformly arranged grooves are used to embed the magnetic alloy wires, forming a magnetic pole array.

[0017] MEMS (Micro-Electro-Mechanical Systems) technology integrates tiny mechanical structures, sensors, actuators, and electronic circuits onto a single chip. MEMS combines microelectronics and mechanical engineering, using micro- and nano-fabrication techniques to manufacture precision mechanical components and electronic systems at the micrometer and nanometer scales.

[0018] Specifically, a uniformly distributed radial magnetic pole array is formed by precisely fabricating multiple radial grooves on a silicon substrate and embedding magnetic alloy wires within them. A circular hole is located at the center of the silicon substrate to facilitate mating with a rotating shaft. As the angle encoder rotates with the shaft, the magnetic alloy wires embedded in the grooves generate periodic magnetic field changes, which are then used by a fixed magnetic sensor (such as a Hall effect sensor) to detect the angle. This encoder provides high-precision angle information and is widely used in industrial automation, robotics, and other fields.

[0019] More specifically, photolithography technology ensures high-precision positioning of the magnetic poles, solving the problem of insufficient precision in traditional machining. Compared with traditional machining methods, angle encoders fabricated using photolithography are simpler, more efficient, and easier to mass-produce. The use of a non-photosensitive polyimide layer to fix and protect the magnetic alloy wire enhances the overall structural stability. This allows for miniaturization of angle detection systems and facilitates integration with other microelectromechanical systems (MEMS).

[0020] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: In this embodiment of the invention, an angle encoder based on a silicon-based magnetic pole array structure constructs multiple equally spaced radial grooves on the outer edge of a silicon substrate using photolithography. High-precision photolithography and plasma etching technologies are employed to achieve precise control of the magnetic pole positions, ensuring the uniformity of the magnetic pole arrangement. After embedding filamentous permalloy magnetic material into the grooves, a stable and uniformly distributed radial magnetic pole array is formed. This array is further encapsulated and fixed by a non-photosensitive polyimide coating, which not only improves the mechanical stability of the structure but also enhances its environmental adaptability. This design can provide a highly consistent periodic magnetic field signal to the magnetic sensor during rotation. Compared to traditional machined magnetic pole code disk structures, it significantly reduces processing errors and structural deviations, improving angle measurement accuracy, repeatability, and overall manufacturing yield, making it particularly suitable for high-precision angle detection scenarios.

[0021] In one possible implementation, the non-photosensitive polyimide cover layer has an opening that matches the size of the circular hole.

[0022] It should be noted that the non-photosensitive polyimide cover layer has an opening with the same size as the circular hole. This opening is aligned with the circular hole in the center of the silicon substrate to ensure that the shaft can be smoothly inserted and combined with the encoder, ensuring smooth movement of the drive shaft, while preventing the cover layer from affecting the connection between the shaft and the silicon substrate.

[0023] In one possible implementation, the magnetic alloy wire includes permalloy wire.

[0024] Permalloy wire is an alloy material commonly used in magnetic applications. It possesses excellent magnetic properties and stability and is frequently used in the manufacture of magnetic components. Permalloy wire is embedded in grooves on a silicon substrate to form a magnetic pole structure. Its magnetic properties provide periodic magnetic field changes for angle encoders, ensuring high-precision angle detection.

[0025] Reference manual attached Figure 2 The diagram shows a schematic of an angle encoder embedded in a stator mold according to an embodiment of the present invention.

[0026] In one possible implementation, it also includes: a stator mold.

[0027] The stator mold has a ring plate at its center that matches the silicon substrate. Magnetic sensors and magnets are arranged symmetrically around the outer periphery of the ring plate. The ring plate encloses and forms an embedding groove that matches the silicon substrate. The magnetic sensors include Hall sensors, fluxgate sensors, tunnel magnetoresistive sensors, giant magnetoresistive sensors, and giant magnetoresistance sensors.

[0028] A silicon substrate with magnetic alloy wires and a non-photosensitive polyimide coating is placed in an embedding groove.

[0029] The magnetic sensor is equipped with a magnet on the back, making it a back-magnetic configuration. The magnetic field generated by the magnet shields it from interference from external magnetic sources.

[0030] It should be noted that the stator mold includes a ring plate, with magnetic sensors and magnets symmetrically arranged on its outer periphery. The insertion groove formed by the ring plate matches the silicon substrate, allowing the silicon substrate, containing magnetic alloy wires and a non-photosensitive polyimide overlay, to be embedded within it. This structure enables the magnetic field change to be detected by magnetic sensors (such as Hall effect sensors or giant magnetoresistive sensors) when the silicon substrate rotates, thus achieving precise angle detection.

[0031] Specifically, the angle encoder, through a silicon-based magnetic pole array structure design combined with high-precision photolithography and etching processes, achieves precise control of the magnetic pole position, significantly improving the uniformity and consistency of the magnetic field distribution. The use of permalloy wire as the magnetic poles ensures stable and reliable magnetic field changes, enhancing the accuracy and repeatability of angle measurements. The addition of a non-photosensitive polyimide coating further improves the structure's mechanical stability and environmental adaptability. Compared to encoders manufactured using traditional machining, the photolithography technology simplifies the manufacturing process, enables mass production, and offers higher production efficiency and lower costs, making it ideal for high-precision angle detection and integrated applications in miniaturized sensing systems.

[0032] Reference manual attached Figure 3 The diagram shows a flowchart of a method for fabricating an angle encoder based on a silicon-based magnetic pole array structure according to an embodiment of the present invention.

[0033] This invention provides a method for fabricating an angle encoder based on a silicon-based magnetic pole array structure, the method comprising: S1: Pre-treatment of the silicon substrate.

[0034] It should be noted that pretreatment of the silicon substrate can ensure that the surface of the silicon substrate is clean and flat, and remove any impurities or contaminants.

[0035] In one possible implementation, S1 specifically includes: S101: Clean the silicon substrate using a cleaning agent, which includes acetone, isopropanol, and deionized water.

[0036] S102: Dry the cleaned silicon substrate to complete the pretreatment of the silicon substrate.

[0037] It should be noted that the silicon substrate is cleaned using cleaning agents such as acetone, isopropanol, and deionized water to remove surface oil, dust, and other contaminants. It is then dried to ensure the substrate surface is completely dry, preparing it for subsequent photolithography, etching, and other processes. This process ensures a clean and flat silicon substrate surface, preventing any impurities from affecting the accuracy of subsequent processing steps.

[0038] S2: A groove mask is fabricated on a pretreated silicon substrate using a patterning process.

[0039] Patterning refers to the process of transferring patterns or structures onto a substrate using techniques such as photolithography. In this process, photoresist is first applied to the surface of a silicon substrate. Then, the pattern is transferred to the photoresist through exposure. After development, the remaining photoresist pattern serves as a mask to guide subsequent etching or other processing steps. A trench mask is a mask pattern prepared on the surface of a silicon substrate using patterning techniques. These patterns define the areas that need to be removed during etching. The mask acts as a protective layer, preventing the etchant from etching the areas of the silicon substrate not covered by the mask, thus ultimately forming the desired trench structure.

[0040] A patterning process is used to fabricate a groove mask on a pre-treated silicon substrate. Specifically, photoresist is first coated on the surface of the silicon substrate, and then exposed and developed to form a patterned mask for subsequent etching steps. These patterns will precisely control the position and shape of the grooves on the silicon substrate during the etching process.

[0041] In one possible implementation, S2 specifically includes: S201: Spin-coating photoresist onto the pretreated silicon substrate.

[0042] S202: Dry the silicon substrate with photoresist spin-coated.

[0043] S203: Expose the dried silicon substrate.

[0044] S204: The exposed silicon substrate is developed using a developing solution to obtain a groove mask.

[0045] The photoresist is specifically AZP4620 photoresist, and its thickness ranges from 10 to 12 micrometers.

[0046] The drying temperature range is specifically 110℃ to 120℃, and the drying time is specifically 240 seconds to 300 seconds.

[0047] The specific exposure method is hard contact exposure, and the specific exposure dose range is 500mJ to 600mJ.

[0048] The developing solution is specifically an alkaline solution with TMAH base, and the developing time ranges from 4 to 6 minutes.

[0049] It should be noted that photolithography can be used to fabricate groove masks, enabling high-precision pattern transfer and ensuring consistency in the size, spacing, and shape of the grooves. This method is more precise and repeatable than traditional machining, making it suitable for mass production. It can improve the accuracy of magnetic pole arrays and the stability of the overall structure, meeting the requirements for high-precision angle detection. By precisely controlling the spin coating, exposure, and development of the photoresist, a high-precision mask pattern is formed on the silicon substrate, ensuring that subsequent etching steps can accurately form the desired groove structure.

[0050] S3: Dry etching is performed on the silicon substrate with the groove mask to obtain the groove.

[0051] Dry etching is a technique that uses gases and high-energy ions to etch materials in a vacuum environment. Unlike wet etching, dry etching utilizes gas reactions and ion bombardment to remove material from the substrate surface through physical or chemical reactions, forming the desired pattern. Common dry etching methods include reactive ion etching (RIE) and plasma etching. The prepared groove mask silicon substrate will undergo dry etching. By using specific gases (such as O2, CF4, C4F8, etc.) in a vacuum environment, ion bombardment and chemical reactions are used to remove the unprotected portions of the silicon substrate, thereby forming the desired groove structure on the silicon substrate.

[0052] In one possible implementation, S3 specifically includes: Dry etching is performed on a silicon substrate with a groove mask prepared using an etching gas.

[0053] The etched silicon substrate is immersed in acetone to remove residual photoresist and obtain a groove.

[0054] The etching gas is specifically a mixture of O2, C4F8, CF4, and Ar. The main RF power range for dry etching is 500W to 2800W. The secondary RF power range for dry etching is 500W to 2800W. The lower electrode LF power range for dry etching is 40W to 400W.

[0055] Soak in acetone for 10 minutes.

[0056] Specifically, a dry etching process is performed using a mixed gas of O2, C4F8, CF4, and Ar. During etching, areas on the silicon substrate not protected by photoresist are precisely removed through ion bombardment and chemical reactions to form the desired grooves. After etching, residual photoresist is removed by immersion in acetone, ensuring a clean silicon substrate surface and preparing it for subsequent steps such as embedding magnetic alloy wires. This process ensures precise control over the shape and depth of the grooves.

[0057] S4: Embed a magnetic alloy wire in the groove.

[0058] It should be noted that the magnetic alloy wire (such as permalloy wire) is embedded into the groove already formed on the silicon substrate, ensuring precise alignment between the magnetic alloy wire and the groove. The purpose of this step is to fix the alloy wire in the groove, forming a stable and uniformly distributed magnetic pole structure, providing periodic magnetic field changes for subsequent angle encoders, and ensuring high-precision angle detection.

[0059] S5: A non-photosensitive polyimide capping layer is formed on a silicon substrate with embedded magnetic alloy wires.

[0060] It should be noted that a non-photosensitive polyimide material is coated onto the surface of the silicon substrate with embedded magnetic alloy wires to form a capping layer. This capping layer not only wraps around the magnetic alloy wires but also fills the grooves, providing physical protection, enhancing the stability of the overall structure, and improving its resistance to environmental interference, ensuring that the magnetic alloy wires are not damaged or displaced during operation.

[0061] In one possible implementation, S5 specifically includes: A non-photosensitive polyimide layer is spin-coated onto a silicon substrate with embedded magnetic alloy wires, wherein the thickness of the non-photosensitive polyimide layer is specifically 50 micrometers.

[0062] In an oxygen-free environment, a silicon substrate with a non-photosensitive polyimide layer spin-coated is subjected to high-temperature baking at a preset temperature and for a preset duration to imidize the non-photosensitive polyimide layer. Specifically, the preset temperature is 180°C and the preset duration is 30 minutes.

[0063] It should be noted that a 50-micron-thick non-photosensitive polyimide layer is spin-coated onto the silicon substrate surface with embedded magnetic alloy wires to ensure uniform coverage and protection of the alloy wires. Subsequently, high-temperature baking is performed in an oxygen-free environment at 180°C for 30 minutes to induce imidization of the polyimide, enhancing its mechanical strength and thermal stability, while also making the layer more stable and providing additional protection.

[0064] S6: Using laser drilling technology, a circular hole is obtained by ablation in the central region of a silicon substrate with a non-photosensitive polyimide coating, thus obtaining an angle encoder.

[0065] In one possible implementation, the radius of the circular hole is specifically 1 cm.

[0066] It should be noted that the radius of the circular hole is 1cm. This size design allows the silicon substrate to precisely match the shaft, ensuring that the angle encoder can be stably connected to the drive shaft, achieving smooth rotation and high-precision angle detection. This hole size is suitable for common shaft interfaces and ensures the reliability and accuracy of the assembly.

[0067] It should be noted that laser drilling technology is used to ablate the center of a silicon substrate coated with a non-photosensitive polyimide layer, forming a circular hole that matches the rotating shaft. This circular hole provides a connection interface for the angle encoder to the drive shaft, ensuring that the encoder can smoothly connect with the shaft and rotate accordingly, thus realizing the angle detection function.

[0068] In practical applications, the fabrication process utilizes precise MEMS technology, employing multiple steps to ensure a high-precision and consistent magnetic pole structure. First, the silicon substrate is pretreated to ensure surface cleanliness, providing a good foundation for subsequent photolithography and etching. A groove mask is fabricated on the silicon substrate using a patterning process, and the groove structure is precisely formed using dry etching. Magnetic alloy wires are then embedded to form uniformly distributed magnetic poles. A non-photosensitive polyimide capping layer provides protection and stability, and a hole is drilled in the center of the silicon substrate using laser drilling technology to ensure precise alignment with the rotating shaft. This process offers advantages such as high precision, strong repeatability, ease of manufacturing, and suitability for large-scale production, making it suitable for high-precision angle detection and miniaturized sensor applications, significantly improving the performance and stability of angle encoders.

[0069] For example, firstly, the silicon substrate is cleaned and dried using acetone, isopropanol, and deionized water. Then, 10-12µm AZP4620 photoresist is spin-coated onto the surface of silicon substrate 1, followed by drying (baking temperature 110℃-120℃, baking time 240s-300s), exposure (hard contact exposure, exposure dose 500mJ-600mJ), and development (developing solution is an alkaline solution containing TMAH groups, development time 4min-6min) to obtain an arrayed magnetic pole groove mask. Next, the silicon substrate is dry-etched (etching gas: O2 / C4F8 / CF4 / Ar; main RF power: 500-2800W; secondary RF power: 500-2800W; lower electrode LF power: 40-400W) to obtain magnetic pole grooves in the outer edge region. Residual photoresist is then removed using acetone (acetone immersion time: 10min). Finally, permalloy wire is embedded in the grooves. Next, a 50µm non-photosensitive polyimide layer is spin-coated onto the silicon substrate and then imidized by high-temperature baking in an oxygen-free environment (baking temperature 180℃, baking time 30min). A 1cm radius shaft drive area is ablated in the center of the silicon substrate using laser drilling technology. The processed silicon substrate is then embedded in a stator mold. A magnetic sensor and magnet are embedded on one side of the stator mold. The magnetic sensor equipped in the stator mold includes, but is not limited to, Hall sensors, fluxgate magnetometers, tunnel magnetoresistive (TMR) sensors, giant magnetoresistive (GMR) sensors, and giant magnetoresistance (GMI) sensors. A magnet is mounted behind the magnetic sensor, forming a back-magnetic configuration. The magnetic field generated by the magnet shields against interference from external magnetic sources, thus obtaining the angle encoder embedded in the stator mold.

[0070] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: In this embodiment of the invention, an angle encoder based on a silicon-based magnetic pole array structure constructs multiple equally spaced radial grooves on the outer edge of a silicon substrate using photolithography. High-precision photolithography and plasma etching technologies are employed to achieve precise control of the magnetic pole positions, ensuring the uniformity of the magnetic pole arrangement. After embedding filamentous permalloy magnetic material into the grooves, a stable and uniformly distributed radial magnetic pole array is formed. This array is further encapsulated and fixed by a non-photosensitive polyimide coating, which not only improves the mechanical stability of the structure but also enhances its environmental adaptability. This design can provide a highly consistent periodic magnetic field signal to the magnetic sensor during rotation. Compared to traditional machined magnetic pole code disk structures, it significantly reduces processing errors and structural deviations, improving angle measurement accuracy, repeatability, and overall manufacturing yield, making it particularly suitable for high-precision angle detection scenarios.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. An angle encoder based on a silicon-based magnetic pole array structure, characterized in that, include: Silicon substrate, magnetic alloy wire, and non-photosensitive polyimide capping layer; The silicon substrate has a circular hole at its center that matches the drive shaft of the angle encoder; Centered on the circular hole, multiple radial grooves are formed on the silicon substrate to form the silicon-based magnetic pole array structure, wherein the spacing between adjacent grooves is equal; The magnetic alloy wire is embedded in the groove; A non-photosensitive polyimide coating is provided on the silicon substrate, wherein the non-photosensitive polyimide coating is used to wrap each of the magnetic alloy wires and fill each of the grooves; When the angle encoder drives the shaft to rotate the silicon substrate, the radial magnetic pole structure formed by the silicon substrate, which is provided with the magnetic alloy wire and the non-photosensitive polyimide coating, provides a periodic and uniform magnetic field distribution for angle detection.

2. The angle encoder based on a silicon-based magnetic pole array structure according to claim 1, characterized in that, The non-photosensitive polyimide cover layer has an opening with the same size as the circular hole.

3. The angle encoder based on a silicon-based magnetic pole array structure according to claim 1, characterized in that, The magnetic alloy wire includes permalloy wire.

4. The angle encoder based on a silicon-based magnetic pole array structure according to claim 1, characterized in that, Also includes: Stator mold; The stator mold has a ring plate at its center that matches the silicon substrate. Magnetic sensors and magnets are arranged symmetrically around the outer periphery of the ring plate. The ring plate encloses and forms an embedding groove that matches the silicon substrate. The magnetic sensors include Hall sensors, fluxgate sensors, tunnel magnetoresistive sensors, giant magnetoresistive sensors, and giant magnetoresistance sensors. A silicon substrate with the magnetic alloy wire and the non-photosensitive polyimide coating disposed thereon is placed in the embedding groove.

5. A method for fabricating an angle encoder based on a silicon-based magnetic pole array structure, characterized in that, The method applied to the angle encoder based on the silicon-based magnetic pole array structure according to any one of claims 1 to 4 includes: S1: Pre-treat the silicon substrate; S2: A groove mask is fabricated on a pretreated silicon substrate using a patterning process; S3: Dry etching is performed on the silicon substrate with the groove mask to obtain the groove; S4: Embed the magnetic alloy wire in the groove; S5: The non-photosensitive polyimide capping layer is formed on a silicon substrate in which the magnetic alloy wire is embedded; S6: Using laser drilling technology, the circular hole is obtained by ablation in the central region of the silicon substrate with the non-photosensitive polyimide coating layer, thus obtaining the angle encoder.

6. The method for fabricating an angle encoder based on a silicon-based magnetic pole array structure according to claim 5, characterized in that, S1 specifically includes: S101: Clean the silicon substrate using a cleaning agent, wherein the cleaning agent includes acetone, isopropanol and deionized water; S102: Dry the cleaned silicon substrate to complete the pretreatment of the silicon substrate.

7. The method for fabricating an angle encoder based on a silicon-based magnetic pole array structure according to claim 5, characterized in that, S2 specifically includes: S201: Spin-coating photoresist onto the pretreated silicon substrate; S202: Dry the silicon substrate spin-coated with the photoresist; S203: Expose the dried silicon substrate; S204: The exposed silicon substrate is developed using a developing solution to obtain the groove mask; The photoresist is specifically AZP4620 photoresist, and the photoresist thickness ranges from 10 to 12 micrometers. The drying temperature range is specifically 110℃ to 120℃, and the drying time is specifically 240 seconds to 300 seconds; The specific exposure method is hard contact exposure, and the specific exposure dose range is 500mJ to 600mJ; The developing solution is specifically an alkaline solution with TMAH base, and the developing time ranges from 4 minutes to 6 minutes.

8. The method for fabricating an angle encoder based on a silicon-based magnetic pole array structure according to claim 5, characterized in that, S3 specifically includes: Dry etching is performed on the silicon substrate with the groove mask prepared using an etching gas; The etched silicon substrate is immersed in acetone to remove residual photoresist and obtain the groove. The etching gas is specifically a mixture of O2, C4F8, CF4 and Ar; the main radio frequency power range of dry etching is 500W to 2800W; the secondary radio frequency power range of dry etching is 500W to 2800W; and the lower electrode LF power range of dry etching is 40W to 400W. Soak in acetone for 10 minutes.

9. The method for fabricating an angle encoder based on a silicon-based magnetic pole array structure according to claim 5, characterized in that, S5 specifically includes: A non-photosensitive polyimide layer is spin-coated on a silicon substrate in which the magnetic alloy wire is embedded, wherein the thickness of the non-photosensitive polyimide layer is specifically 50 micrometers; In an oxygen-free environment, a silicon substrate with the non-photosensitive polyimide layer spin-coated is subjected to high-temperature baking at a preset temperature and for a preset duration to imidize the non-photosensitive polyimide layer. Specifically, the preset temperature is 180°C and the preset duration is 30 minutes.

10. The method for fabricating an angle encoder based on a silicon-based magnetic pole array structure according to claim 5, characterized in that, The radius of the circular hole is 1 cm.

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