Scanning micromirror chip and preparation method therefor, and scanning micromirror

Abstract

The present application relates to the technical field of micro electromechanical systems. Provided are a scanning micromirror chip and a preparation method therefor, and a scanning micromirror. The scanning micromirror chip comprises a first support structure and a micromirror structure, wherein the first support structure comprises a first through cavity; the micromirror structure is arranged in the first through cavity, and is rotationally connected to the first support structure; and the first support structure and the micromirror structure each comprise a substrate layer and a dielectric layer, which are stacked, the substrate layers being made of silicon carbide. The embodiments in the present application can improve the stability of the scanning micromirror chip and prolong the operating life thereof.

Description

Scanning micromirror chip and its fabrication method, scanning micromirror

[0001] This application claims priority to Chinese Patent Application No. 202510120976.0, filed on January 23, 2025, entitled “Scanning Micromirror Chip and Preparation Method Thereof, Scanning Micromirror”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of micro-optical device technology, and in particular to a scanning micromirror chip and its fabrication method, and a scanning micromirror. Background Technology

[0003] With the rapid development of micro-nano fabrication technology, microelectromechanical systems (MEMS) scanning micromirrors have been widely used in various fields such as industrial production, automobiles, mobile phones, and security, based on their advantages of small size integration, low power consumption, light weight, and ease of mass production.

[0004] In related technologies, microelectromechanical systems (MEMS) scanning micromirror chips typically use silicon on an insulating substrate (SOI) as the substrate, on which drive coils, torsion beams, and micromirrors are fabricated. When the drive coil is energized, the energized drive coil generates a Lorentz force in the magnetic field produced by the external permanent magnet, driving the micromirror to perform torsional scanning around the torsion beam.

[0005] However, the aforementioned microelectromechanical system scanning micromirror chips have drawbacks such as poor stability and short service life. Summary of the Invention

[0006] In view of the above problems, this application provides a scanning micromirror chip and its preparation method, as well as a scanning micromirror, which can improve the stability and working life of the scanning micromirror chip.

[0007] A first aspect of this application provides a scanning micromirror chip, comprising:

[0008] A first support structure, the first support structure including a first through cavity;

[0009] A micromirror structure is disposed in the first through cavity and rotatably connected to the first support structure; both the first support structure and the micromirror structure include a substrate layer and a dielectric layer stacked together; the substrate layer is made of silicon carbide.

[0010] In one possible implementation, the scanning micromirror chip further includes a second support structure, which is disposed on the dielectric layer of the first support structure;

[0011] The second support structure includes a second through cavity, which communicates with the first through cavity and exposes at least the micromirror structure.

[0012] In one possible implementation, the second through cavity also exposes a portion of the first support structure.

[0013] In one possible implementation, the second support structure is connected to the dielectric layer of the first support structure via a glass slurry layer.

[0014] In one possible implementation, the scanning micromirror chip further includes a blocking structure disposed on the side of the dielectric layer of the first support structure opposite to the substrate layer and surrounding the micromirror structure.

[0015] In one possible implementation, the blocking structure includes a blocking protrusion, the side of the blocking protrusion facing away from the substrate layer protruding from the side of the dielectric layer facing away from the substrate layer.

[0016] In one possible implementation, the scanning micromirror chip further includes a driving coil disposed on the side of the dielectric layer of the micromirror structure opposite to the substrate layer, for driving the micromirror structure to rotate relative to the first support structure;

[0017] The blocking structure surrounds the micromirror structure and the drive coil.

[0018] In one possible implementation, a pad is also included, which is disposed on the side of the dielectric layer of the first support structure opposite to the substrate layer and is electrically connected to the drive coil.

[0019] The barrier structure surrounds the micromirror structure, the drive coil, and the pad.

[0020] In one possible implementation, along the extending direction of the drive coil, the drive coil includes a first end and a second end, the first end being located between the second end and the center of the first through cavity;

[0021] The pads include a first pad and a second pad, the first pad being electrically connected to the first end and the second pad being electrically connected to the second end.

[0022] In one possible implementation, the scanning micromirror chip further includes an interconnect structure disposed within the dielectric layer of the micromirror structure;

[0023] The interconnection structure includes a first interconnection contact and a second interconnection contact. The first interconnection contact is opposite to the first end, and the second interconnection contact is located between the first interconnection contact and the first pad, and is offset from the drive coil.

[0024] The first end is electrically connected to the first interconnect contact, and the second interconnect contact is electrically connected to the first pad.

[0025] In one possible implementation, the micromirror structure includes a drive frame, a micromirror, a first torsion arm, and a second torsion arm. One end of the drive frame is connected to the first support structure via the first torsion arm, and the other end of the drive frame is connected to the micromirror via the second torsion arm.

[0026] A second aspect of this application provides a method for fabricating a scanning micromirror chip, comprising:

[0027] A first support structure layer is provided, the first support structure layer comprising a substrate material layer and a dielectric material layer stacked together; the substrate material layer is made of silicon carbide.

[0028] A patterned first support structure layer is formed to create a first support structure and a micromirror structure, wherein the micromirror structure is rotatably connected to the first support structure; both the first support structure and the micromirror structure include a substrate layer and a dielectric layer stacked together; wherein the retained substrate material layer constitutes the substrate layer, and the retained dielectric material layer constitutes the dielectric layer.

[0029] In one possible implementation, after the step of providing the first support structure layer and before the step of patterning the first support structure layer, the fabrication method further includes:

[0030] A driving coil is formed and disposed on the side of the dielectric material layer opposite to the substrate material layer; the driving coil is used to drive the micromirror structure to rotate relative to the first support structure;

[0031] A pad is formed, which is disposed on the dielectric material layer and electrically connected to the drive coil.

[0032] In one possible implementation, the preparation method further includes:

[0033] A barrier structure is formed on the dielectric material layer; the barrier structure at least surrounds the drive coil and the pad.

[0034] In one possible implementation, after the step of providing the first support structure layer and before the step of forming the drive coil on the dielectric material layer, the fabrication method further includes:

[0035] An interconnect structure is formed in the dielectric material layer;

[0036] The dielectric material layer is patterned to form at least two conductive vias in the dielectric material layer; the at least two conductive vias expose portions of the interconnect structure;

[0037] The step of forming the drive coil further includes:

[0038] Conductive plugs are simultaneously formed in at least two of the conductive vias, and the conductive plugs are connected to the interconnect structure; wherein the end of the drive coil facing the center of the dielectric material layer is electrically connected to the pad through at least two of the conductive plugs and the interconnect structure.

[0039] In one possible implementation, the drive coil, the blocking structure, and the pad are fabricated in the same step.

[0040] In one possible implementation, the steps of forming the drive coil, the blocking structure, and the pad include:

[0041] A seed layer is formed on the dielectric material layer;

[0042] The seed layer is patterned to form a first filling region, a second filling region, and a third filling region in the seed layer, wherein the first filling region exposes the conductive via.

[0043] A drive coil and a conductive plug for connecting the drive coil and the interconnection structure are formed in the first filling area; a pad is formed in the second filling area; and a blocking structure is formed in the third filling area.

[0044] Remove the remaining seed layer.

[0045] In one possible implementation, a second support structure having a second through cavity is provided;

[0046] A glass slurry layer is formed on one side of the second support structure;

[0047] The second support structure is bonded to the first support structure layer through the glass paste layer; wherein the second through cavity exposes the drive coil, the blocking structure and the pad.

[0048] In one possible implementation, after the step of bonding the second support structure to the first support structure layer via the glass slurry layer and before the step of patterning the first support structure layer, the fabrication method further includes:

[0049] Thin the first support structure layer.

[0050] In one possible implementation, after the step of thinning the first support structure layer, the fabrication method further includes:

[0051] A third support structure layer is formed, which is disposed on the side of the second support structure opposite to the first support structure layer and fills the second through cavity.

[0052] In one possible implementation, the step of patterning the first support structure layer includes:

[0053] A first mask layer is formed on the first support structure layer. The first mask layer includes two first mask openings and two second mask openings. The two first mask openings are spaced apart along a first direction. The two second mask openings are disposed in the area enclosed by the two first mask openings and are spaced apart along a second direction. The second direction intersects the first direction.

[0054] The first support structure layer exposed in the first mask opening and the second mask opening is removed to form a first support structure and a micromirror structure; the micromirror structure includes a drive frame, a micromirror, a first torsion arm and a second torsion arm, one end of the drive frame is connected to the micromirror through the first torsion arm, and the other end of the drive frame is connected to the first support structure through the second torsion arm.

[0055] In one possible implementation, after the step of patterning the first support structure layer, the fabrication method further includes:

[0056] Remove the first mask layer;

[0057] A second mask layer with a third mask opening is formed on the first support structure layer, the third mask opening exposing the micromirror;

[0058] A reflective film layer is formed on the surface of the micromirror opposite to the second support structure;

[0059] Remove the third support structure layer.

[0060] A third aspect of this application provides a scanning micromirror, including the scanning micromirror chip described in the first aspect and a magnetic component, wherein the scanning micromirror chip is located within the magnetic field formed by the magnetic component.

[0061] The scanning micromirror chip and its fabrication method provided in this application embodiment, and the scanning micromirror itself, improve the film layers of the scanning micromirror chip so that both the first support structure and the micromirror structure include a stacked substrate layer and a dielectric layer, with the substrate layer being made of silicon carbide. On one hand, silicon carbide's high yield strength and high Young's modulus can improve the impact and vibration resistance of the scanning micromirror chip, thereby enhancing its performance. On the other hand, silicon carbide also possesses high thermal conductivity, which can quickly transfer the heat generated by the scanning micromirror chip to the outside, preventing heat accumulation within the chip, extending its lifespan, and increasing the maximum temperature it can withstand.

[0062] In addition to the technical problems solved by the embodiments of this application, the technical features constituting the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions described above, the scanning micromirror chip and its preparation method provided by the embodiments of this application, other technical problems that the scanning micromirror can solve, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further explained in detail in the specific implementation. Attached Figure Description

[0063] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 is a schematic diagram of the structure of the scanning micromirror chip provided in an embodiment of this application;

[0065] Figure 2 is a cross-sectional view along the AA direction in Figure 1;

[0066] Figure 3 is a flowchart of the method for fabricating a scanning micromirror chip provided in an embodiment of this application;

[0067] Figure 4 is a schematic diagram of the formation of the substrate material layer in the fabrication method of the scanning micromirror chip provided in the embodiments of this application;

[0068] Figure 5 is a schematic diagram of the formation of a dielectric material layer in the fabrication method of the scanning micromirror chip provided in the embodiments of this application;

[0069] Figure 6 is a schematic diagram of the formation of the barrier structure in the fabrication method of the scanning micromirror chip provided in the embodiment of this application;

[0070] Figure 7 is a schematic diagram of the formation of the second support structure in the fabrication method of the scanning micromirror chip provided in the embodiment of this application;

[0071] Figure 8 is a schematic diagram of the thinning of the first support structure layer in the method for fabricating a scanning micromirror chip provided in the embodiments of this application;

[0072] Figure 9 is a schematic diagram of the formation of the third support structure layer in the fabrication method of the scanning micromirror chip provided in the embodiment of this application;

[0073] Figure 10 is a schematic diagram of the patterned first support structure in the fabrication method of the scanning micromirror chip provided in the embodiments of this application;

[0074] Figure 11 is a schematic diagram of removing the third support structure layer in the fabrication method of the scanning micromirror chip provided in the embodiment of this application.

[0075] Explanation of reference numerals in the attached figures: 10: First support structure; 11: First through cavity; 12: Substrate layer; 13: Dielectric layer; 20: Micromirror structure; 21: Drive frame; 22: Second torsion arm; 23: First torsion arm; 24: Micromirror; 30: Second support structure; 31: Second through cavity; 40: Glass slurry layer; 50: Barrier structure; 60: Drive coil; 61: First end; 62: Second end; 70: Pad; 71: First pad; 72: Second pad; 80: Interconnect structure; 90: First support structure layer; 91: Substrate material layer; 92: Dielectric material layer; 100: Third support structure layer; 110: Bonding adhesive layer. Detailed Implementation

[0076] As described in the background section, scanning micromirror chips in related technologies suffer from poor stability and short operating life. The inventors have discovered that the reason for this problem is that scanning micromirror chips are usually fabricated using silicon-on-insulator (SOI) as the supporting component. However, silicon is a brittle material with a low yield strength of only 7 GPa, which leads to the current scanning micromirror chips, such as electromagnetic MEMS scanning micromirror chips, having low impact and vibration resistance.

[0077] In addition, silicon has a low thermal conductivity, and the heat generated by the scanning micromirror chip during operation seriously affects the working stability and lifespan of the scanning micromirror, and also limits its working environment temperature to no more than 85°C.

[0078] To address the aforementioned technical problems, this application provides a scanning micromirror chip and its fabrication method, as well as a scanning micromirror. By improving the film layers of the scanning micromirror chip, both the first support structure and the micromirror structure include a stacked substrate layer and a dielectric layer, with the substrate layer made of silicon carbide. On one hand, silicon carbide's high yield strength and high Young's modulus can improve the impact and vibration resistance of the scanning micromirror chip, thereby enhancing its performance. On the other hand, silicon carbide also possesses high thermal conductivity, which can rapidly transfer the heat generated by the scanning micromirror chip to the outside, preventing heat accumulation within the chip, extending its lifespan, and increasing its maximum temperature tolerance.

[0079] To make the above-mentioned objectives, features, and advantages of the embodiments of this application more apparent and understandable, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0080] Please refer to Figure 1. This application provides a scanning micromirror chip, which is used in scanning micromirror devices.

[0081] The scanning micromirror chip includes a first support structure 10, which provides support for the scanning micromirror chip. The first support structure 10 includes a first through cavity 11, which extends through the first support structure 10 along its thickness direction.

[0082] The scanning micromirror chip also includes a micromirror structure 20, which is disposed in the first through cavity 11 and rotatably connected to the first support structure 10. By changing the angle of the micromirror structure 20, the incident beam is deflected, thereby realizing the scanning of the beam in two-dimensional or three-dimensional space.

[0083] The first support structure 10 and the micromirror structure 20 each include at least a substrate layer 12 and a dielectric layer 13 stacked together; the substrate layer 12 is made of silicon carbide.

[0084] In this embodiment, by improving the hierarchical structure of the scanning micromirror chip, both the first support structure 10 and the micromirror structure 20 include a substrate layer 12 and a dielectric layer 13 stacked together, with the substrate layer 12 made of silicon carbide. On one hand, silicon carbide has high yield strength and high Young's modulus, which can improve the impact and vibration resistance of the scanning micromirror chip, thereby improving its performance. On the other hand, silicon carbide also has high thermal conductivity, which can quickly transfer the heat generated by the scanning micromirror chip to the outside, preventing heat accumulation within the chip, extending its lifespan, and increasing its maximum temperature tolerance.

[0085] In one possible implementation, referring to Figure 1, the scanning micromirror chip further includes a second support structure 30 disposed on the dielectric layer 13 of the first support structure 10. Exemplarily, the second support structure 30 is disposed on the side of the dielectric layer 13 of the first support structure 10 facing away from the substrate layer.

[0086] The second support structure 30 includes a second through cavity 31, which communicates with the first through cavity 11. In the thickness direction of the substrate layer 12, the micromirror structure 20 is projected orthogonally onto the second support structure 30 and is covered by the second through cavity 31. In other words, the micromirror structure 20 can be seen from the second through cavity 31. The thickness direction of the substrate layer 12 can be the Z-direction in Figure 1.

[0087] In this embodiment, the second support structure 30 can provide additional mechanical support for the scanning micromirror chip, thereby enhancing the stability and durability of the scanning micromirror chip.

[0088] Furthermore, in the thickness direction of the substrate layer 12, the micromirror structure 20 is projected orthogonally onto the second support structure 30 and is covered by the second through cavity 31. During rotation, the micromirror structure 20 can be located within the second through cavity 31, thus avoiding interference between the second support structure 30 and the micromirror structure 20. This ensures the continuity and integrity of the optical path, reducing optical signal attenuation and distortion. Furthermore, it prevents the second support structure 30 from obstructing the rotation of the micromirror structure 20, ensuring the normal operation of the scanning micromirror chip.

[0089] It should be noted that the micromirror structure 20 is projected orthogonally onto the second support structure 30 and is covered by the second through cavity 31. The area of ​​the second through cavity 31 is equal to the area of ​​the first through cavity 11; for example, the projection of the second through cavity 31 onto the first support structure 10 completely coincides with the first through cavity 11. Alternatively, it can be understood that the area of ​​the second through cavity 31 is larger than the area of ​​the first through cavity 11. That is, in the thickness direction of the substrate layer 12, a portion of the first support structure 10 is projected orthogonally onto the second support structure 30 and is covered by the second through cavity 31. This, on the one hand, helps reduce occlusion and reflection in the optical path, thereby improving the scanning accuracy of the scanning micromirror chip. On the other hand, it increases the heat dissipation surface area, which helps to dissipate heat more effectively, preventing the micromirror structure 20 from overheating during high-frequency operation and extending the lifespan of the scanning micromirror chip. Furthermore, by exposing more of the first support structure 10, layout area can be provided for the layout of other components of the scanning micromirror chip, making it easier to integrate other optical or electronic components, improving the integration and functional diversity of the scanning micromirror chip.

[0090] In this embodiment, the second support structure 30 can be a single film layer or a stacked structure, and the second support structure 30 can be formed in the first support structure 10 by a deposition process or connected to the first support structure 10 by other structures.

[0091] For example, referring to Figure 2, the second support structure 30 is connected to the dielectric layer 13 of the first support structure 10 via a glass paste layer 40. This configuration simplifies the fabrication process of the scanning micromirror chip and reduces its fabrication cost.

[0092] The fabrication process of a scanning micromirror chip typically involves placing a glass paste layer 40 on a second support structure 30. With the second support structure 30 aligned with the first support structure 10, the glass paste layer 40 is bonded to the first support structure 10 at a specific bonding temperature. It should be noted that the bonding temperature is usually very high, for example, 430°C. Therefore, during the bonding process, the glass paste layer 40 is prone to being in a molten state, and may even become fluid.

[0093] Therefore, the scanning micromirror chip provided in this embodiment also includes a blocking structure 50, which is disposed on the side of the dielectric layer 13 of the first support structure 10 away from the substrate layer 12 and surrounds the micromirror structure 20.

[0094] The blocking structure 50 can prevent the molten or flowing glass slurry layer 40 from overflowing to the micromirror structure 20, thereby preventing the molten or flowing glass slurry layer 40 from affecting the rotation of the micromirror structure 20 and ensuring the normal scanning of the scanning micromirror chip.

[0095] It should be noted that the blocking structure 50 can be a blocking groove or a blocking protrusion. For example, the blocking structure 50 is a blocking protrusion that protrudes from the dielectric layer 13, forming a blocking sidewall. This maximizes the blocking effect of the blocking structure 50, allowing the scanning micromirror chip to scan normally. Furthermore, the blocking protrusion increases the rigidity of the overall structure, enhances the stability of the micromirror structure 20, and reduces potential deformation during operation.

[0096] In one possible implementation, the scanning micromirror chip further includes a drive coil 60, which is disposed on the micromirror structure 20 and insulated from the substrate layer 12 of the micromirror structure 20. The drive coil 60 is used to drive the micromirror structure 20 to rotate relative to the first support structure 10.

[0097] The driving coil 60 is disposed on the surface of the dielectric layer 13 of the micromirror structure 20 away from the substrate layer 12; taking the orientation shown in Figure 1 as an example, the driving coil 60 is disposed on the top surface of the substrate layer 12.

[0098] Alternatively, the drive coil 60 can be disposed within the dielectric layer 13 of the micromirror structure 20. In this case, there is a gap between the bottom surface of the drive coil 60 and the top surface of the substrate layer 12 of the micromirror structure 20, which can prevent leakage current from the scanning micromirror chip and improve the performance of the scanning micromirror chip.

[0099] It should be noted that when the driving coil 60 is disposed on the surface of the dielectric layer 13 of the micromirror structure 20 away from the substrate layer 12, both the driving coil 60 and the dielectric layer 13 opposite to the driving coil are located on the surface of the substrate layer 12. Alternatively, the driving coil 60 and the dielectric layer 13 opposite to the driving coil can be located inside the substrate layer 12. In specific fabrication, the substrate layer 12 of the micromirror structure 20 can be patterned first, and a groove can be formed in the substrate layer 12. Then, a dielectric layer 13 covering the top surface of the substrate layer 12 and the inner wall of the groove can be formed. Finally, the driving coil 60 can be formed by deposition.

[0100] The driving coil 60 is wound in the plane of the dielectric layer 13; and the blocking structure 50 surrounds the micromirror structure 20 and the driving coil 60. In this way, the blocking structure 50 can also prevent the molten or flowing glass paste layer from overflowing to the driving coil 60, ensuring that the driving coil 60 is electrically sound, avoiding short circuits, insulation failures or performance degradation caused by the overflow of the glass paste layer 40, and improving the yield of the scanning micromirror chip.

[0101] In this embodiment, the drive coil 60 needs to cooperate with the magnetic components of the peripheral device. For example, the drive coil 60 is located in the steady magnetic field formed by the magnetic components. When power is supplied to the drive coil 60, the drive coil 60 generates a Lorentz force, thereby driving the micromirror structure 20 to perform scanning. The scanning can be a two-dimensional scan or a one-dimensional scan.

[0102] To facilitate the supply of current to the drive coil 60, the scanning micromirror chip provided in this embodiment also includes a pad 70. The pad 70 is disposed on the side of the dielectric layer 13 of the first support structure 10 away from the substrate layer 12 and is electrically connected to the drive coil 60.

[0103] The barrier structure 50 also surrounds the micromirror structure 20, the drive coil 60, and the pad 70. In other words, the barrier structure 50 can not only surround the micromirror structure 20 and the drive coil 60, but also surround the pad 70. This protects the micromirror structure 20 and the drive coil 60 while preventing the molten or flowing glass paste layer from overflowing onto the pad 70 and preventing the glass paste layer from covering the pad 70. This prevents the pad 70 from failing, ensures the reliability of the electrical connection, and thus ensures that the scanning micromirror chip can operate normally.

[0104] To provide a clearer description of the connection between the drive coil 60 and the pad 70, this embodiment further refines the description of the drive coil 60 and the pad 70. Exemplarily, along the extending direction of the drive coil 60, the drive coil 60 includes a first end 61 and a second end 62. The first end 61 is located near the center of the first through cavity 11, or in other words, relative to the center of the first through cavity 11, the first end 61 can be the inner end of the drive coil 60; the second end can be the outer end of the drive coil 60.

[0105] The pad 70 includes a first pad 71 and a second pad 72. The first pad 71 is electrically connected to the first end 61, and the second pad 72 is electrically connected to the second end 62. The first pad 71 and the second pad 72 can be connected to the positive and negative terminals of the power supply unit of the peripheral device, respectively, thereby ensuring that the drive coil 60 has a constant current.

[0106] It should be noted that, along the direction from the first end 61 to the second end 62, the first end 61 is located on the side of the drive coil 60 facing the first through cavity 11. In order to facilitate the electrical connection between the first end 61 and the first pad 71, the first end 61 and the first pad 71 can be connected by a bridging wiring layer, or other methods can be used.

[0107] For example, the scanning micromirror chip further includes an interconnect structure 80, wherein the interconnect structure 80 is disposed in the dielectric layer of the micromirror structure 20. The interconnect structure 80 includes a first interconnect contact (not shown) and a second interconnect contact (not shown), the first interconnect contact being opposite to the first end 61, and the second interconnect contact being located between the first interconnect contact and the first pad 71, and offset from the drive coil 60.

[0108] The first end 61 is electrically connected to the first interconnect contact, and the second interconnect contact is electrically connected to the first pad 71. In this way, by setting the first end 61 to be electrically connected to the first pad 71 in the interconnect structure 80, a short circuit can be avoided between the first end 61 and the first pad 71 and the drive coil 60, thus ensuring the normal operation of the scanning micromirror chip.

[0109] In one possible implementation, the micromirror structure 20 includes a drive frame 21, a micromirror 24, a first torsion arm 23, and a second torsion arm 22. A drive coil 60 is disposed on the drive frame 21.

[0110] One end of the drive frame 21 is connected to the first support structure 10 via the first torsion arm 23, and the other end of the drive frame 21 is connected to the micromirror 24 via the second torsion arm 22.

[0111] The drive coil 60 can drive the micromirror 24 to rotate around the first torsion arm 23, or it can drive the micromirror 24 to rotate around the second torsion arm 22, so that the micromirror 24 can perform two-dimensional scanning.

[0112] In this embodiment, the first torsion arm 23 can extend along a first direction, and the second torsion arm 22 can extend along a second direction, with the first and second directions intersecting. For example, the first and second directions can be perpendicular to each other, making the rotation axes of the micromirror 24 independent, reducing possible coupling effects during scanning, and improving scanning accuracy and stability. The first direction can be the Y direction in Figure 1, and the second direction can be the X direction in Figure 1.

[0113] This application provides a method for fabricating a scanning micromirror chip, and the structural diagrams involved in each step are drawn with reference to the BB cross-sectional view in Figure 1.

[0114] Please refer to Figure 3. The fabrication method of the scanning micromirror chip includes the following steps:

[0115] Step S100: Provide a first support structure layer, the first support structure layer including a substrate material layer and a dielectric material layer stacked together; the substrate material layer is made of silicon carbide.

[0116] For example, referring to Figure 4, a substrate material layer 91 is provided, which is made of silicon carbide. Compared with silicon-on-insulator (SOI) in related technologies, silicon carbide has higher yield strength, higher Young's modulus and higher thermal conductivity.

[0117] This embodiment also requires polishing both sides of the substrate material layer 91 to reduce its roughness. The thickness of the substrate material layer 91 can be 350 μm.

[0118] Please refer to Figure 5. Then, a dielectric material layer 92 is formed on the substrate material layer 91 using a deposition process. For example, the dielectric material layer 92 can be formed using processes such as chemical vapor deposition (CVD), physical vapor deposition (PVD), or atomic layer deposition (ALD).

[0119] The first support structure layer 90 consists of a substrate material layer 91 and a dielectric material layer 92 stacked together. The dielectric material layer 92 is made of silicon dioxide, but is not limited to this. The thickness of the dielectric material layer 92 is 280 nm to 320 nm. For example, the thickness of the dielectric material layer 92 is 30 nm.

[0120] Step S200: Pattern the first support structure layer to form a first support structure and a micromirror structure, wherein the micromirror structure is rotatably connected to the first support structure; both the first support structure and the micromirror structure include a substrate layer and a dielectric layer stacked together; wherein the retained first substrate material layer constitutes the substrate layer and the retained dielectric material layer constitutes the dielectric layer.

[0121] This embodiment improves the film layers of the scanning micromirror chip, so that the first support structure layer 90 includes a substrate material layer 91 and a dielectric material layer 92 stacked together, with the substrate material layer 91 being made of silicon carbide. On one hand, silicon carbide has high yield strength and high Young's modulus, which can improve the impact and vibration resistance of the scanning micromirror chip, thereby improving its performance. On the other hand, silicon carbide also has high thermal conductivity, which can quickly transfer the heat generated by the scanning micromirror chip to the outside, preventing heat accumulation within the chip, extending its lifespan, and increasing its maximum high-temperature tolerance.

[0122] In one possible implementation, after the step of providing the first support structure layer and before the step of patterning the first support structure layer, the method for fabricating the scanning micromirror chip further includes:

[0123] A drive coil is formed and disposed on the side of the dielectric material layer away from the substrate material layer; the drive coil is used to drive the micromirror structure to rotate relative to the first support structure.

[0124] Please continue referring to Figure 1. A driving coil 60 is formed on the surface of the dielectric material layer 92 opposite to the substrate material layer 91. It should be noted that the driving coil 60 can be formed by deposition or electroplating processes; this embodiment does not impose a specific limitation. The material of the driving coil 60 may include copper, titanium, copper, or a composite layer thereof.

[0125] The method for fabricating a scanning micromirror chip further includes: forming a pad 70, which is disposed on a dielectric material layer 92, and the pad 70 is spaced apart from a driving coil 60; wherein the pad 70 and the driving coil 60 are electrically connected to provide current to the pad 70. The pad 70 and the driving coil 60 can be made of the same material.

[0126] The fabrication method of the scanning micromirror chip further includes: forming a barrier structure 50, which is disposed on a dielectric material layer 92; wherein the barrier structure 50 at least surrounds the drive coil 60 and the pad 70. In this way, the barrier structure 50 can be used to protect the drive coil 60 and the pad 70, ensuring that the drive coil 60 can drive the micromirror structure 20 to rotate normally.

[0127] To achieve electrical connection between the drive coil 60 and the pad 70, the fabrication method of the scanning micromirror chip provided in this example further includes forming an interconnect structure 80 in the dielectric material layer 92.

[0128] For example, the dielectric material layer in this embodiment may include a first dielectric material layer and a second dielectric material layer stacked together. The step of forming the interconnect structure 80 may include: forming an interconnect material layer on the first dielectric material layer, patterning the interconnect material layer, removing a portion of the interconnect material layer, and the remaining interconnect material layer constituting the interconnect structure 80. The patterning process may be wet etching.

[0129] In this embodiment, the interconnect material layer can be a single film layer or a stacked structure. For example, the interconnect material layer includes a first interconnect material layer and a second interconnect material layer stacked together, wherein the first interconnect material layer is made of titanium and the second interconnect material layer is made of gold. The thickness of the first interconnect material layer is 20 nm, and the thickness of the second interconnect material layer is 150 nm.

[0130] After the interconnect structure 80 is formed, a second dielectric material layer is formed covering the interconnect structure 80 and the exposed first dielectric material layer. The material of the second dielectric material layer may include silicon dioxide, and the thickness of the second dielectric material layer is 1 μm.

[0131] Subsequently, a dielectric material layer is patterned to form at least two conductive vias within the dielectric material layer; the at least two conductive vias expose portions of the interconnect structure 80. For example, a portion of the second dielectric material layer may be removed by wet etching to form at least two conductive vias within the second dielectric material layer.

[0132] The step of forming the drive coil also includes:

[0133] Conductive plugs are formed in at least two conductive vias, and the conductive plugs are connected to the interconnect structure; wherein, the end of the drive coil facing the center of the dielectric material layer is electrically connected to the pad through at least two conductive plugs and the interconnect structure.

[0134] With this configuration, the end of the drive coil facing the center of the dielectric material layer, or in other words, the first end 61 of the drive coil 60 is electrically connected to the pad 70, while also preventing short circuits with other areas of the drive coil 60.

[0135] It should be noted that the driving coil 60, pad 70, blocking structure 50, and conductive plug can be fabricated simultaneously or in different processes. For example, the driving coil 60, blocking structure 50, and pad 70 are fabricated in the same step. This simplifies the fabrication process of the scanning micromirror chip and reduces its fabrication difficulty.

[0136] In one possible implementation, the steps of forming the drive coil, the blocking structure, and the pads include:

[0137] A seed layer is formed on a dielectric material layer; for example, a seed layer is formed on a second dielectric material layer. The seed layer can be a stacked structure, for example, the seed layer includes a first seed layer and a second seed layer stacked together, the second seed layer being disposed on the first seed layer, and the first seed layer being made of titanium with a thickness of 20 nm; the second seed layer being made of copper with a thickness of 150 nm.

[0138] The seed layer is patterned to form a first filling region, a second filling region, and a third filling region in the seed layer. The first filling region exposes a conductive via. It should be noted that the patterning process can be a traditional photolithography process, which will not be described in detail here.

[0139] Please refer to Figure 6. A drive coil 60 and a conductive plug for connecting the drive coil 60 and the interconnect structure 80 are formed in the first filling area; a pad 70 is formed in the second filling area; and a barrier structure 50 is formed in the third filling area. This step can be formed by a sputtering process.

[0140] Remove the remaining seed layer. This step can be performed using a wet etching process.

[0141] In this embodiment, the seed layer provides a good foundation for the subsequent sputtering process, making it easier to form the drive coil 60, pad 70 and barrier structure 50 using the sputtering process, thus reducing the difficulty of manufacturing the above components.

[0142] In particular, seed layers with a multilayer structure (such as a combination of titanium and copper) can effectively reduce the difficulty of subsequent sputtering processes. The titanium layer, as the first seed layer, has good adhesion and stability, while the copper layer, as the second seed layer, has excellent conductivity and easy deposition characteristics.

[0143] It should be noted that Figure 6 is a cross-sectional view along the BB direction in Figure 1. The drive coil 60 and the pad 70 are not visible in the cross-section. Therefore, only the blocking structure 50 is shown in Figure 6.

[0144] In one possible implementation, the fabrication method of the scanning micromirror chip also includes:

[0145] A second support structure with a second through cavity is provided; for example, referring to Figure 7, a 6-inch single-crystal silicon wafer with double-sided polishing and a thickness of 350 μm is prepared, and the single-crystal silicon wafer is used as the second support structure 30. Subsequently, a portion of the single-crystal silicon wafer can be removed by a dry etching process to form the second support structure with the second through cavity.

[0146] In this way, the second support structure 30 can be used as a support for the scanning micromirror chip, thereby improving the structural strength of the scanning micromirror chip.

[0147] Subsequently, a glass paste layer 40 is formed on one side of the second support structure 30. For example, the glass paste can be screen-printed and pre-sintered at a temperature of 120°C.

[0148] Please refer to Figure 7. The dielectric material layer of the second support structure 30 and the first support structure layer 90 is bonded, that is, the second support structure 30 and the first support structure layer 90 are bonded through the glass paste layer 40, so that the second through cavity exposes the drive coil 60, the blocking structure 50 and the pad 70.

[0149] In this step, a bonding machine can be used for bonding. The second support structure 30, containing pre-sintered glass paste, is aligned with the first support structure layer 90 and placed in the bonding machine for bonding at a bonding temperature of 430°C. This solves the bonding problem between the first support structure layer 90 and the second support structure 30, and also features low bonding cost, mature technology, low requirements on the surface quality of the first and second support structure layers 90 and 30, and easy bonding.

[0150] In addition, the introduction of the second support structure 30 can solve the problem of thinning the first support structure layer 90 in the future, and realize the free control of the thickness of the first support structure layer 90.

[0151] At this time, the glass paste layer 40 is easily in a molten state at 430℃. The blocking structure 50 can prevent the molten paste from overflowing to the drive coil 60 and the pad 70, thus ensuring the normal operation of the scanning micromirror chip.

[0152] In one possible implementation, after the step of bonding the second support structure to the first support structure layer via the glass slurry layer and before the step of patterning the first support structure layer, the method for fabricating the scanning micromirror chip further includes: thinning the first support structure layer.

[0153] Referring to Figure 8, by way of example, the side of the first support structure layer 90 facing away from the second support structure 30 is thinned and polished to reduce the thickness of the first support structure layer 90. For example, the thickness of the thinned first support structure layer 90 is 30 μm.

[0154] The method for fabricating scanning micromirror chips provided in this embodiment can be applied to the production of multi-specification electromagnetic MEMS scanning micromirror chips. After the same first support structure layer 90 is used for unified batch production of driving coils, bonding of the first support structure layer 90 and the second support structure 30, the thickness of the first support structure layer 90 can be flexibly controlled according to the specific specification requirements in the step of thinning and polishing the first support structure layer 90. It has the advantages of flexible process and is more conducive to the co-line production of multi-specification products.

[0155] Furthermore, the arrangement of the drive coil 60 and the second support structure 30 on the same side of the first support structure layer 90 allows the thickness of the final first support structure 10 to be adjusted according to different chip specifications after the previous processes such as bonding the drive coil 60, the second support structure 30 and the first support structure layer 90 are completed. This improves the flexibility of the manufacturing process and facilitates the co-line production of products with multiple specifications.

[0156] In one possible implementation, after the step of thinning the first support structure layer, the fabrication method of the scanning micromirror chip further includes:

[0157] Referring to Figure 9, a third support structure layer 100 is formed. The third support structure layer 100 is disposed on the side of the second support structure 30 opposite to the first support structure layer 90 and fills the second through cavity. The third support structure layer 100 can also be connected to the second support structure 30 via a bonding adhesive layer 110, thus filling the second through cavity 31. For example, a 6-inch third support structure layer 100 can be temporarily bonded to the second support structure 30 using the bonding adhesive layer 110. For instance, the third support structure layer 100 provides temporary structural support for the scanning micromirror chip. When transferring the scanning micromirror chip within the device, the third support structure layer 100 can be moved, reducing damage to other structures of the scanning micromirror chip.

[0158] In one possible implementation, referring to Figures 1 and 10, the scanning micromirror chip described above is flipped so that the side of the first support structure layer 90 facing away from the second support structure 30 faces upward.

[0159] A first mask layer (not shown in the figure) is formed on the first support structure layer 90. The first mask layer includes two first mask openings and two second mask openings. The two first mask openings are arranged at intervals along a first direction. The two second mask openings are disposed in the area enclosed by the two first mask openings and are arranged at intervals along a second direction. The second direction intersects with the first direction. The first direction is the Y direction in Figure 1, and the second direction is the X direction in Figure 1.

[0160] The first support structure layer exposed in the first mask opening and the second mask opening is removed to form the first support structure 10 and the micromirror structure 20. The micromirror structure 20 includes a drive frame 21, a micromirror 24, a first torsion arm 23 and a second torsion arm 22. One end of the drive frame 21 is connected to the micromirror 24 through the first torsion arm 23, and the other end of the drive frame 21 is connected to the first support structure 10 through the second torsion arm 22.

[0161] This embodiment can form a scanning micromirror chip by directly etching through the first support structure layer 90 in one dry etching process. This avoids the complex double-sided deep trench etching required by traditional silicon-based MEMS micromirror chip processes and the huge cost of constructing an etching self-stopping layer in advance on the wafer. In this way, the requirements for the first support structure layer 90, as well as the process cost and process difficulty, are greatly reduced. This method is applicable not only to the chip fabrication of silicon carbide-based materials, but also to the chip fabrication of silicon-based materials.

[0162] In one possible implementation, after the step of patterning the first support structure layer, the fabrication method of the scanning micromirror chip further includes:

[0163] Remove the first mask layer. For example, the first mask layer can be removed with a cleaning solution.

[0164] A second mask layer (not shown in the figure) with a third mask opening is formed on the first support structure layer, and the third mask opening exposes the micromirror 24.

[0165] A reflective film is formed on the surface of the micromirror 24 opposite to the second support structure 30; for example, a 100 nm thick aluminum layer can be deposited on the surface of the micromirror 24 opposite to the second support structure 30 by sputtering process to form the reflective film.

[0166] Please refer to Figure 11. Finally, remove the third support structure layer using a special adhesive remover.

[0167] This application also provides a scanning micromirror, including a magnetic component and a scanning micromirror chip as described in any of the above embodiments, wherein the scanning micromirror chip is located within the magnetic field formed by the magnetic component. The scanning micromirror provided in this embodiment can be applied to fields such as LiDAR, smart car lights, head-up displays (HUDs), and augmented reality glasses (AR glasses).

[0168] Since the scanning micromirror includes the scanning micromirror chip described in any of the above embodiments, the structure and beneficial effects of including the scanning micromirror chip will not be described in detail here.

[0169] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0170] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0171] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A scanning micromirror chip, wherein, include: A first support structure (10) includes a first through cavity (11); A micromirror structure (20) is disposed in the first through cavity (11) and rotatably connected to the first support structure (10); both the first support structure (10) and the micromirror structure (20) include a substrate layer (12) and a dielectric layer (13) stacked together; the substrate layer (12) is made of silicon carbide.

2. The scanning micromirror chip according to claim 1, wherein, The scanning micromirror chip further includes a second support structure (30), which is disposed on the dielectric layer (13) of the first support structure (10), and the second support structure (30) and the micromirror structure (20) are located on the same side of the first support structure (10). The second support structure (30) includes a second through cavity (31), which is connected to the first through cavity (11); In the thickness direction of the substrate layer (12), the micromirror structure (20) is projected orthogonally onto the second support structure (30) and is covered by the second through cavity (31).

3. The scanning micromirror chip according to claim 2, wherein, In the thickness direction of the base layer (12), a portion of the first support structure (10) is projected onto the second support structure (30) and is covered by the second through cavity (31).

4. The scanning micromirror chip according to claim 2 or 3, wherein The second support structure (30) is connected to the dielectric layer (13) of the first support structure (10) through a glass slurry layer (40).

5. The scanning micromirror chip according to any one of claims 1-4, wherein, The scanning micromirror chip also includes a blocking structure (50), which is disposed on the side of the dielectric layer (13) of the first support structure (10) away from the substrate layer (12) and surrounds the micromirror structure (20).

6. The scanning micromirror chip according to claim 5, wherein, The blocking structure (50) is a blocking protrusion, and the side of the blocking protrusion facing away from the base layer (12) protrudes from the side of the medium layer (13) facing away from the base layer (12).

7. The scanning micromirror chip according to any one of claims 1-6, wherein, The scanning micromirror chip also includes a driving coil (60), which is disposed on the micromirror structure (20) and is insulated from the substrate layer (12) of the micromirror structure (20); wherein, the driving coil (60) is used to drive the micromirror structure (20) to rotate relative to the first support structure (10).

8. The scanning micromirror chip according to claim 7, wherein, The driving coil (60) is disposed on the surface of the dielectric layer (13) of the micromirror structure (20) away from the substrate layer (12); Alternatively, the drive coil (60) may be disposed within the dielectric layer (13) of the micromirror structure (20).

9. The scanning micromirror chip according to claim 7, wherein, The drive coil (60) is wound in the plane of the dielectric layer (13); The blocking structure (50) surrounds the micromirror structure (20) and the drive coil (60).

10. The scanning micromirror chip according to any one of claims 7-9, wherein, It also includes pads (70), which are disposed on the side of the dielectric layer (13) of the first support structure (10) away from the base layer (12) and are electrically connected to the drive coil (60); The blocking structure (50) also surrounds the drive coil (60) and the pad (70).

11. The scanning micromirror chip of claim 10, wherein, Along the extending direction of the drive coil (60), the drive coil (60) includes a first end (61) and a second end (62), the first end (61) being close to the center of the first through cavity (11); The pad (70) includes a first pad (71) and a second pad (72), the first pad (71) being electrically connected to the first end (61) and the second pad being electrically connected to the second end.

12. The scanning micromirror chip according to any one of claims 7-11, wherein, The scanning micromirror chip also includes an interconnect structure (80), which is disposed within the dielectric layer (13) of the micromirror structure (20); The interconnection structure (80) includes a first interconnection contact and a second interconnection contact. The first interconnection contact is opposite to the first end (61), and the second interconnection contact is located between the first interconnection contact and the first pad (71) and is offset from the drive coil. The first end (61) is electrically connected to the first interconnect contact, and the second interconnect contact is electrically connected to the first pad (71).

13. The scanning micromirror chip according to any one of claims 1-12, wherein, The micromirror structure (20) includes a drive frame (21), a micromirror (24), a first torsion arm (23) and a second torsion arm (22). One end of the drive frame (21) is connected to the first support structure (10) through the first torsion arm (23), and the other end of the drive frame (21) is connected to the micromirror (24) through the second torsion arm (22).

14. A method for fabricating a scanning micromirror chip, wherein, include: A first support structure layer is provided, the first support structure layer comprising a substrate material layer and a dielectric material layer stacked together; The substrate material layer is made of silicon carbide; A patterned first support structure layer is formed to create a first support structure and a micromirror structure, wherein the micromirror structure is rotatably connected to the first support structure; both the first support structure and the micromirror structure include a substrate layer and a dielectric layer stacked together; wherein the retained substrate material layer constitutes the substrate layer, and the retained dielectric material layer constitutes the dielectric layer.

15. The method for fabricating a scanning micromirror chip according to claim 14, wherein, After providing the first support structure layer and before patterning the first support structure layer, the fabrication method further includes: A driving coil is formed and disposed on the side of the dielectric material layer opposite to the substrate material layer; the driving coil is used to drive the micromirror structure to rotate relative to the first support structure; A pad is formed, which is disposed on the dielectric material layer and electrically connected to the drive coil.

16. The method for fabricating a scanning micromirror chip according to claim 15, wherein, The preparation method further includes: A barrier structure is formed on the dielectric material layer; the barrier structure at least surrounds the drive coil and the pad.

17. The method for fabricating a scanning micromirror chip according to claim 16, wherein, After the step of providing the first support structure layer and before the step of forming the driving coil on the dielectric material layer, the fabrication method further includes: An interconnect structure is formed in the dielectric material layer; The dielectric material layer is patterned to form at least two conductive vias in the dielectric material layer; the at least two conductive vias expose portions of the interconnect structure; The step of forming the drive coil further includes: Conductive plugs are simultaneously formed in at least two of the conductive vias, and the conductive plugs are connected to the interconnect structure; wherein the end of the drive coil facing the center of the dielectric material layer is electrically connected to the pad through at least two of the conductive plugs and the interconnect structure.

18. The method for fabricating a scanning micromirror chip according to claim 17, wherein, The drive coil, the blocking structure, and the pad are prepared in the same step.

19. The method for fabricating a scanning micromirror chip according to claim 18, wherein, The steps of forming the drive coil, the blocking structure, and the pad include: A seed layer is formed on the dielectric material layer; The seed layer is patterned to form a first filling region, a second filling region, and a third filling region in the seed layer, wherein the first filling region exposes the conductive via. A drive coil and a conductive plug for connecting the drive coil and the interconnection structure are formed in the first filling area; a pad is formed in the second filling area; and a blocking structure is formed in the third filling area. Remove the remaining seed layer.

20. The method for fabricating a scanning micromirror chip according to claim 19, wherein, Provide a second support structure having a second through cavity; A glass slurry layer is formed on one side of the second support structure; The second support structure is bonded to the first support structure layer through the glass paste layer; wherein the second through cavity exposes the drive coil, the blocking structure and the pad.

21. The method for fabricating a scanning micromirror chip according to claim 20, wherein, After the step of bonding the second support structure to the first support structure layer via the glass slurry layer, and before the step of patterning the first support structure layer, the fabrication method further includes: Thin the first support structure layer.

22. The method for fabricating a scanning micromirror chip according to claim 21, wherein, After the step of thinning the first support structure layer, the preparation method further includes: A third support structure layer is formed, which is disposed on the side of the second support structure opposite to the first support structure layer and fills the second through cavity.

23. The method for fabricating a scanning micromirror chip according to claim 22, wherein, The steps for patterning the first support structure layer include: A first mask layer is formed on the first support structure layer. The first mask layer includes two first mask openings and two second mask openings. The two first mask openings are spaced apart along a first direction. The two second mask openings are disposed in the area enclosed by the two first mask openings and are spaced apart along a second direction. The second direction intersects the first direction. The first support structure layer exposed in the first mask opening and the second mask opening is removed to form a first support structure and a micromirror structure; the micromirror structure includes a drive frame, a micromirror, a first torsion arm and a second torsion arm, one end of the drive frame is connected to the micromirror through the first torsion arm, and the other end of the drive frame is connected to the first support structure through the second torsion arm.

24. The method for fabricating a scanning micromirror chip according to claim 23, wherein, After the step of patterning the first support structure layer, the fabrication method further includes: Remove the first mask layer; A second mask layer with a third mask opening is formed on the first support structure layer, the third mask opening exposing the micromirror; A reflective film layer is formed on the surface of the micromirror opposite to the second support structure; Remove the third support structure layer.

25. A scanning micromirror, wherein, The invention includes the scanning micromirror chip and magnetic component as described in any one of claims 1-13, wherein the scanning micromirror chip is located within the magnetic field formed by the magnetic component.

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