High temperature resistant electrostatically actuated vertical micromirror optical switch chip for on-chip integration

Abstract

This invention discloses a high-temperature resistant electrostatically driven vertical micromirror optical switch chip for on-chip integration, comprising a wafer and a fixed electrode, an electrostatically driven vertical micromirror, and a reflector. The electrostatically driven vertical micromirror is cantilevered or comb-shaped, and the electrostatically driven vertical micromirror or reflector is planar, convex, or concave. The movement of emitted light is achieved through the repulsion or attraction between the fixed electrode and the electrostatically driven vertical micromirror. The concave or convex mirror deflects the angle of the emitted light, thereby achieving optical signal switching. The fabrication process of the optical switch chip includes: deeply etching the fixed electrode, vertical micromirror, and reflector on the upper surface of the wafer to form the fixed electrode, vertical micromirror, and reflector; planarizing and polishing the vertical sidewalls; depositing a silicon dioxide insulating layer on the surface of the wafer, fixed electrode, vertical micromirror, and reflector; depositing a metal layer on the surface of the fixed electrode, vertical micromirror, and reflector; and forming interconnects and metallized fixed electrode, vertical micromirror, and reflector by a stripping method.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronics technology, and particularly relates to a high-temperature electrostatically driven vertical micromirror optical switch chip for on-chip integration. Background Technology

[0002] With the continuous development of optoelectronic information technology, fiber optic interconnection networks have become one of the main methods of modern long-distance communication, boasting advantages such as high transmission speed and large capacity. During the transmission of optical signals, routing and switching are required. Optical switches are crucial devices that switch optical signals from input ports to output ports, completing optical signal switching and possessing significant application value.

[0003] Silicon-based optoelectronics, exemplified by ring resonator optical switches, is a two-dimensional technology. This makes it difficult to fully utilize the mechanical properties of silicon as a carrier, and also limits the propagation speed and loss of light due to waveguide manufacturing processes. Microelectromechanical systems (MEMS), on the other hand, are a three-dimensional technology. They can fabricate three-dimensional micromirrors on single-crystal silicon wafers, enabling the alteration of the optical path as light propagates through air. This fully utilizes the mechanical, electrical, and optical properties of silicon, offering advantages such as small size, high integration, and low power consumption. However, traditional MEMS optical micromirror arrays are typically horizontal structures, generally used for vertical light propagation control, and are difficult to implement horizontal optical path transmission and control. Summary of the Invention

[0004] The purpose of this application is to provide a high-temperature resistant electrostatically driven vertical micromirror optical switch chip for on-chip integration. It utilizes a vertical deep etching process to fabricate cantilevered or comb-shaped vertically oriented MEMS driveable micromirrors, enabling horizontal deflection and control of the optical path. Since the MEMS process used is fully compatible with integrated circuit processes, and there are no high-temperature processes exceeding 400°C in the entire process, the optical switch chip can be manufactured using MEMS processes after the integrated circuit chip manufacturing process is completed, achieving on-chip integration of IC-MEMS. Furthermore, this invention is a passive device structure, and the materials used can operate normally at temperatures above 120°C, thus possessing certain high-temperature resistance.

[0005] The technical solution is as follows:

[0006] A high-temperature resistant electrostatically driven vertical micromirror optical switch chip for on-chip integration includes a wafer and a fixed electrode thereon, an electrostatically driven vertical micromirror, and a reflector. The electrostatically driven vertical micromirror is a cantilevered electrostatically driven vertical micromirror or a comb-type electrostatically driven vertical micromirror. The electrostatically driven vertical micromirror or the reflector is planar, convex, or concave. The movement of the emitted light is achieved by the repulsion or attraction between the fixed electrode and the electrostatically driven vertical micromirror. The concave or convex electrostatically driven vertical micromirror or the reflector deflects the angle of the emitted light, thereby achieving optical signal switching.

[0007] The fabrication process of the optical switch chip includes:

[0008] Manufacturing steps for fixed electrodes, vertical micromirrors, and mirrors: The fixed electrodes, vertical micromirrors, and mirrors are formed by deep etching on the upper surface of the wafer, and the vertical sidewalls formed by deep etching are planarized and polished.

[0009] Silicon dioxide layer deposition step: Deposit a silicon dioxide insulating layer on the surface of the wafer, fixed electrode, vertical micromirror and reflector;

[0010] Electrode and interconnect manufacturing steps: deposit metal layers on the surfaces of the fixed electrode, vertical micromirror and reflector, and form interconnects, metallized fixed electrodes, metallized vertical micromirrors and metallized reflectors by peeling.

[0011] Furthermore, it includes a combination of one or more sets of the fixed electrodes and electrostatically driven vertical micromirrors, wherein one or more of the electrostatically driven vertical micromirrors are planar, convex or concave.

[0012] The reflector can be segmented or integral, and can be any one or any combination of a plane reflector, a convex reflector, and a concave reflector.

[0013] Furthermore, if the electrostatically driven vertical micromirror is a cantilever electrostatically driven vertical micromirror, then multiple combinations of the fixed electrodes and electrostatically driven vertical micromirrors are provided to level the light.

[0014] Furthermore, in the manufacturing steps of the fixed electrode, vertical micromirror, and reflector, the vertical sidewalls after deep etching are planarized by immersing the fixed electrode, vertical micromirror, and reflector in a mixed solution of potassium hydroxide or tetramethylammonium hydroxide and isopropanol.

[0015] Further, the silicon dioxide layer deposition step includes:

[0016] Silicon dioxide insulating layers are deposited on the surfaces of micromirrors and single-crystal silicon wafers using inductively coupled plasma chemical vapor deposition (ICP-CVD) or plasma-enhanced chemical vapor deposition (PECVD).

[0017] Furthermore, the electrode and interconnect manufacturing steps include:

[0018] Photoresist is applied using a spray coating method, and then exposed and developed to form electrode and interconnect patterns.

[0019] Deposited metal layer;

[0020] The photoresist and excess metal layers are removed by stripping to form lead interconnects, metallized fixed electrodes, metallized cantilever electrostatically driven vertical micromirrors, and metallized reflectors.

[0021] Furthermore, the material of the metal layer is titanium / gold, aluminum, chromium / gold, titanium / platinum / gold, titanium / nickel / gold, titanium / copper, chromium / copper, or titanium / nickel / copper.

[0022] Furthermore, if the electrostatically driveable vertical micromirror has a concave or convex surface, then in the manufacturing steps of the fixed electrode, vertical micromirror, and reflector, a shallow fixed electrode, a shallow vertical micromirror with a convex or concave surface, and a shallow reflector are formed by photolithography and etching, and the electrode and interconnect manufacturing steps include:

[0023] A thick photoresist is coated on the upper surface of the wafer, and then exposed and developed to form a base pattern.

[0024] Based on the deep silicon etching of the base pattern, a base is formed below the shallow fixed electrode, the shallow cantilever electrostatically driven vertical micromirror, and the shallow reflector.

[0025] Photoresist is applied using a spray coating method, and then exposed and developed to form electrode and interconnect patterns.

[0026] Deposited metal layer;

[0027] The photoresist and excess metal layers are removed by stripping to form interconnects, metallized fixed electrodes, metallized cantilever electrostatically driven vertical micromirrors with convex or concave surfaces, and metallized reflectors.

[0028] Furthermore, if the electrostatically driven vertical micromirror is a comb-type electrostatically driven vertical micromirror, then after the electrode and interconnect manufacturing steps, the wafer is immersed in hydrofluoric acid to remove the buried oxide layer silicon dioxide in the silicon-on-insulator wafer or the sacrificial layer deposited on the single crystal silicon wafer, to obtain a suspended comb structure.

[0029] Furthermore, if the electrostatically driven vertical micromirror is a comb-type electrostatically driven vertical micromirror, then before the manufacturing steps of the fixed electrode, vertical micromirror, and reflector, a suspension groove is etched on the back side of the wafer, the back side of the wafer is anodicly bonded to a glass wafer containing potassium and sodium ions, and the front side of the wafer is thinned and polished.

[0030] The technical solutions provided by the embodiments of this application may include the following beneficial effects:

[0031] First, the present invention uses a microelectronic deep etching process to fabricate an electrostatically driven micromirror structure on a silicon wafer. By changing the different curvature positions of the incident light illuminating the convex and concave mirrors, the optical path angle is converted, thereby realizing the exchange of optical signals. It has low requirements for the light source, fast transmission rate, and also has the advantages of photon multi-channel, large bandwidth, and high speed.

[0032] Second, the MEMS process used in this invention is fully compatible with the integrated circuit process, and there are no high-temperature processes above 400°C in the entire process. Therefore, the manufacturing process of the integrated circuit chip can be completed first, and then the manufacturing process of the optical switch chip can be completed using the MEMS process, integrating it from the wafer that realizes IC-MEMS.

[0033] Third, the present invention is a passive device structure, and the materials used can work normally at temperatures above 120°C, exhibiting certain high-temperature resistance.

[0034] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0035] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0036] Figure 1 The diagram shows the process flow of the optical switch chip with cantilever electrostatically driven vertical micromirrors of the present invention, where (a)-(f) are wafer cross-sectional views of each process.

[0037] Figure 2 The diagram shows the process flow chart of the optical switch chip with cantilever electrostatically driven vertical micromirrors of the present invention, where (a)-(f) are top views of the wafers for each process.

[0038] Figure 3 The diagram shows the three-dimensional working principle of a high-temperature resistant optical switch with a cantilever electrostatically driven vertical micromirror, where (a) is an optical switch composed of convex mirrors and (b) is an optical switch composed of concave mirrors.

[0039] Figure 4 The diagram shows a top view of the working principle of a high-temperature resistant optical switch with a cantilever electrostatically driven vertical micromirror, where (a) is a working principle diagram of an optical switch composed of convex mirrors and (b) is a working principle diagram of an optical switch composed of concave mirrors.

[0040] Figure 5 The diagram shown is a cross-sectional schematic of the vertical control of the optical path by a cantilever electrostatically driven vertical micromirror.

[0041] Figure 6 The diagram shows the working principle of the optical switch chip when the cantilever electrostatically driven vertical micromirror is a concave mirror and a convex mirror. (a) is the working principle of the optical switch chip when the cantilever electrostatically driven vertical micromirror is a concave mirror, and (b) is the working principle of the optical switch chip when the cantilever electrostatically driven vertical micromirror is a convex mirror.

[0042] Figure 7 The diagram shows the process flow of the optical switch chip when the cantilever electrostatically driven vertical micromirror is a concave mirror and a convex mirror. (a)-(h) are wafer cross-sectional views of each process, and (i) is a schematic diagram of the overall movable micromirror structure consisting of a shallow cantilever electrostatically driven vertical micromirror with a convex reflector L and a base formed by deep etching.

[0043] Figure 8 The diagram shows the top view of the process flow of the optical switch chip when the cantilever electrostatically driven vertical micromirror is a concave mirror and a convex mirror, where (a)-(h) are the top views of the wafers for each process.

[0044] Figure 9 The diagram shows a top view of the working principle of a comb-type electrostatically driven vertical micromirror optical switch chip. (a) is a top view of the working principle of an optical switch with a planar reflector and an external convex reflector for electrostatically driven vertical micromirror; (b) is a top view of the working principle of an optical switch with a planar reflector and an external convex reflector for electrostatically driven vertical micromirror; (c) is a top view of the working principle of an optical switch with a built-in convex reflector for electrostatically driven vertical micromirror; and (d) is a top view of the working principle of an optical switch with a built-in concave reflector for electrostatically driven vertical micromirror.

[0045] Reference numerals: 1. Single-crystal silicon wafer; 2. Fixed electrode; 3. Cantilever electrostatically driven vertical micromirror; 4. Reflector; 5. First silicon dioxide insulating layer; 6. First photoresist; 7. First metal layer; 8. First metallized fixed electrode; 9. First metallized cantilever electrostatically driven vertical micromirror; 10. First metallized reflector; 11. Shallow fixed electrode; 12. Shallow cantilever electrostatically driven vertical micromirror; 13. Shallow reflector; 14. Second silicon dioxide insulating layer; 15. Thick photoresist; 16. Base; 17. Second photoresist; 18. Second metal layer; 19. Second metallized fixed electrode; 20. Second metallized cantilever electrostatically driven vertical micromirror; 21. Second metallized reflector. Detailed Implementation

[0046] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0047] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0048] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0049] The present invention is described using an electrostatically driven vertical micromirror switch chip as an example. However, the method used in the present invention is not limited to the structure composed of a fixed electrode, a cantilever electrostatically driven vertical micromirror, a plane mirror, a convex mirror, and a concave mirror. It is also applicable to the structure composed of a fixed electrode, a comb-type electrostatically driven vertical micromirror, a plane mirror, a convex mirror, and a concave mirror.

[0050] This application provides a high-temperature resistant electrostatically driven vertical micromirror optical switch chip for on-chip integration, comprising a wafer and on-chip fixed electrodes, an electrostatically driven vertical micromirror, and a reflector. The electrostatically driven vertical micromirror is either a cantilevered electrostatically driven vertical micromirror or a comb-type electrostatically driven vertical micromirror. The electrostatically driven vertical micromirror or the reflector is planar, convex, or concave. By the repulsion or attraction between the fixed electrodes and the electrostatically driven vertical micromirror, incident light is irradiated at different curvature positions of the convex or concave reflector, thereby causing a deflection of the outgoing light angle and achieving optical signal switching.

[0051] In a specific implementation, the optical switch chip includes a combination of one or more sets of fixed electrodes and electrostatically driven vertical micromirrors, one or more of which are planar, convex or concave; the reflector is segmented or integral, and the reflector is any one or any combination of planar reflector, convex reflector and concave reflector.

[0052] Using single-crystal silicon wafer 1 as material ( Figure 1 (a) Figure 2 (a) of the above, the manufacturing process of the optical switch chip including the cantilever electrostatically driven vertical micromirror includes the following steps:

[0053] (1) Manufacturing steps of fixed electrode 2, vertical micro mirror and reflector 4: The fixed electrode 2, vertical micro mirror and reflector 4 are formed by deep etching on the upper surface of the wafer, and the vertical sidewalls formed by deep etching are planarized and polished.

[0054] Specifically, deep grooves are photolithographically etched and deeply etched on the upper surface of the single-crystal silicon wafer 1 to form one or more sets of fixed electrodes 2, cantilevered electrostatically driven vertical micromirrors 3, and reflectors 4. The reflectors 4 can be planar, convex, or concave mirrors; when there are multiple sets, they can be combinations of the various reflectors 4 described above. Then, preferably, the vertical sidewalls are planarized by immersion in a mixed solution of potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH) and isopropanol (IPA). The typical roughness value of the vertical sidewalls after planarization is better than 3 nanometers. Figure 1 (b) Figure 2 (b) in the middle.

[0055] (2) First silicon dioxide layer deposition step: depositing a first silicon dioxide insulating layer on the surface of the wafer, fixed electrode, vertical micromirror and reflector;

[0056] Preferably, an inductively coupled plasma chemical vapor deposition (ICPCVD) or plasma-enhanced chemical vapor deposition (PECVD) method is used to deposit a first silicon dioxide insulating layer 5 on the surface of the micromirror and single-crystal silicon wafer. Figure 1 (c) Figure 2 (c) in the middle.

[0057] (3) First electrode and interconnect manufacturing step: deposit a first metal layer 7 on the surface of the fixed electrode 2, vertical micromirror and reflector 4, and form interconnects and first metallized fixed electrode 8, first metallized vertical micromirror and first metallized reflector 10 by peeling.

[0058] Specifically, it may include the following sub-steps:

[0059] The first photoresist 6 is applied using a spray coating method, and then exposed and developed to form electrode and interconnect patterns. Figure 1 (d) in Figure 2 (d) in the middle.

[0060] A first metal layer 7 is deposited. The preferred material for the metal layer is titanium / gold, but it can also be aluminum, chromium / gold, titanium / platinum / gold, titanium / nickel / gold, titanium / copper, chromium / copper, titanium / nickel / copper, etc. Figure 1 (e) in Figure 2 (e) in the middle.

[0061] The first photoresist 6 and excess metal layer are removed by stripping in acetone, ethanol, or a resist remover to form lead interconnects, a first metallized fixed electrode 8, a first metallized cantilever electrostatically driven vertical micromirror 9, and a first metallized reflector 10. Figure 1 (f) in Figure 2 (f) in the middle.

[0062] The working principle of the optical switch chip with the electrostatically driven vertical micromirror structure is that the movement of the emitted light is achieved by the repulsion or attraction between the fixed electrode and the electrostatically driven vertical micromirror. The light path illuminates the different curvature positions of the concave or convex electrostatically driven vertical micromirror or reflector, thereby causing the angle of the emitted light to deflect and realizing the conversion of the light path angle, thus realizing the exchange of optical signals.

[0063] by Figure 3 (a) and Figure 4 Example (a) illustrates the working principle of the optical switch composed of convex mirrors in this invention. When no voltage is applied to the first metallized fixed electrode 8 and the first metallized cantilever electrostatically driven vertical micromirror 9, they remain vertical. A beam of light is reflected between the first metallized mirror 10 and the first metallized cantilever electrostatically driven vertical micromirror 9 along the path ①→②→③→④→⑤→⑥→⑦ and irradiates the convex mirror J: I→B→I→D→I→F→I→H→J. Figure 4 In (a) of the diagram, solid lines represent the polarity. When a voltage of +V is applied to the electrode plates A, C, E, and G of the first metallized fixed electrode 8, and +V, 0, 0, and +V are applied to the B, D, F, and H of the first metallized cantilever electrostatically driven vertical micromirror 9, respectively, the vertical micromirrors B, D, F, and H deflect due to the Coulomb force. B and H are repelled by the electrostatic force and deflect away from the first metallized fixed electrode 8, while D and F are attracted by the electrostatic force and deflect towards the first metallized fixed electrode 8. A beam of light still enters from the same position, and after reflection between the first metallized reflector 10 and the deflected first metallized cantilever electrostatically driven vertical micromirror 9, it illuminates the convex reflector J. The incident position is different from when no voltage is applied; that is, before and after the voltage is applied, the incident light illuminates positions with different curvatures on the convex reflector J, resulting in angular deflection. In this way, by adjusting the position and magnitude of the applied voltage, the position of the light shining on the convex mirror J with different curvatures can be controlled, thereby achieving the angle control of the light in the horizontal direction.

[0064] by Figure 3 (b) and Figure 4The working principle of the optical switch composed of concave mirrors in this invention is illustrated using example (b) as an example. Similar to the working principle of the optical switch chip composed of convex mirrors J, the optical switch chip composed of concave mirrors K also achieves deflection of B, D, F, and H by applying different electrostatic voltages to the electrode plates A, C, E, and G in the first metallized fixed electrode 8 and the B, D, F, and H of the first metallized cantilever electrostatically driven vertical micromirror 9. This causes the incident light to strike positions with different curvatures on the concave mirror K, resulting in angular deflection and achieving the conversion of the optical path angle and the exchange of optical signals. The difference lies in the different curvature directions of the concave and convex mirrors, thus resulting in different deflection angles of the light in the horizontal direction.

[0065] Figure 5 The diagram shows the cross-sectional principle of the vertical optical path control by the cantilever electrostatically driven vertical micromirror. Due to the deflection of B, D, F, and H of the first metallized cantilever electrostatically driven vertical micromirror 9, the horizontally incident light will be deflected in the z-axis direction after reflection by B. By increasing D, F, and H, it can be ensured that the outgoing light after being controlled by the optical switch can still maintain the same horizontal height as the incident light.

[0066] It should be noted that the main purpose of D, F, and H is to keep the outgoing light and the incident light at the same horizontal level. However, for applications where the detector or receiving fiber optic port can be arranged in space, only one set of fixed electrodes A-vertical micromirror B-convex reflector J or fixed electrodes A-vertical micromirror B-concave reflector K can be used.

[0067] As another embodiment of the present invention Figure 6 The diagram shows the principle of the optical switch chip controlling the incident light angle when the first metallized cantilever electrostatically driven vertical micromirror 9 is a concave or convex mirror. Figure 4 Compared to the embodiments shown, Figure 6 The convex mirror J and concave mirror K located in the first metallized mirror 10 are replaced with a convex mirror L and a concave mirror M that can be electrostatically driven vertical micromirrors. However, since the concave and convex surfaces will affect the force on the electrostatically driven vertical micromirror during deflection, relative to... Figure 1 and Figure 2 The manufacturing process shown should be adjusted accordingly.

[0068] A light computing chip that can be electrostatically driven as both concave and convex mirrors using a single-crystal silicon wafer 1 as the material. Figure 7 (a) Figure 8 In (a)), the preparation process includes:

[0069] (I) Manufacturing steps of shallow fixed electrode, shallow vertical micromirror and shallow reflector: Shallow fixed electrode 11, shallow vertical micromirror and shallow reflector 13 are formed by deep etching on the upper surface of the wafer, and the vertical sidewalls formed by deep etching are planarized and polished.

[0070] Specifically, a shallow fixed electrode 11, a shallow cantilever electrostatically driven vertical micromirror 12 with a convex reflector L or a concave reflector M, and a shallow reflector 13 are formed on the upper surface of the single-crystal silicon wafer 1 by photolithography and etching, with a depth preferably 20 micrometers. Then, preferably, the vertical sidewalls after deep etching are planarized by immersion in a mixed solution of potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH) and isopropanol (IPA). The roughness of the vertical sidewalls after planarization is typically better than 3 nanometers. Figure 7 (b) Figure 8 (b) in the middle.

[0071] (II) Second silicon dioxide layer deposition step: Deposit a second silicon dioxide insulating layer 14 on the surface of the wafer, shallow fixed electrode 11, shallow vertical micromirror and shallow reflector 13;

[0072] Specifically, a second silicon dioxide insulating layer 14 is deposited on the fixed electrode, vertical micromirror, reflector, and single-crystal silicon wafer surface using inductively coupled plasma chemical vapor deposition (ICPCVD) or plasma-enhanced chemical vapor deposition (PECVD). Figure 7 (c) Figure 8 (c) in the middle.

[0073] (III) Second electrode and interconnect manufacturing steps: A base is etched to form below the shallow fixed electrode 11, shallow vertical micromirror and shallow reflector 13 and a second metal layer 18 is deposited on the upper surface. Interconnects and second metallized fixed electrode 19, second metallized vertical micromirror and second metallized reflector 21 are formed by peeling.

[0074] The preferred method is to coat a thick photoresist layer 15 on the surface of the micromirror and the single-crystal silicon wafer using a spin coating method, followed by exposure and development to form the base pattern. Figure 7 (d) in Figure 8 (d)). Deeply etch silicon to form a square base 16 below the shallow fixed electrode 11, the shallow cantilever electrostatically driven vertical micromirror 12, and the shallow reflector 13. Figure 7 (e) in Figure 8 (e) in the middle.

[0075] The second photoresist 17 is applied using a spray coating method, and then exposed and developed to form electrode and interconnect patterns. Figure 7 (f) in Figure 8 (f) in the middle.

[0076] A second metal layer 18 is deposited. The preferred material for the metal layer is titanium / gold, but it can also be aluminum, chromium / gold, titanium / platinum / gold, titanium / nickel / gold, titanium / copper, chromium / copper, titanium / nickel / copper, etc. Figure 7 (g) in Figure 8 (g) in the middle.

[0077] The second photoresist 17 and excess metal layer are removed using a stripping method to form lead interconnects and a second metallized fixed electrode 19, a second metallized cantilever electrostatically driven vertical micromirror 20 with a convex reflector L or a concave reflector M, and a second metallized reflector 21. Figure 7 (h) in Figure 8 (h) in the middle. Figure 7 (i) shows a schematic diagram of an integral movable micromirror structure consisting of a shallow cantilever electrostatically driven vertical micromirror 12 with a convex reflector L and a base 16 formed by deep etching.

[0078] As another embodiment of the present invention Figure 9 The image shown is a top view illustrating the working principle of a comb-type electrostatically driven vertical micromirror optical switch. Figure 9 (a) is a top view of the working principle of an optical switch with a planar reflector N and an external convex reflector O that can be electrostatically driven vertical micromirrors. Figure 9 (b) is a top view of the working principle of an electrostatically driven vertical micromirror consisting of a plane mirror N and an external convex mirror P. Figure 9 (c) is a top view of the working principle of an electrostatically driven vertical micromirror with a built-in convex reflector Q. Figure 9 (d) in the figure is a top view of the working principle of an electrostatically driven vertical micromirror optical switch with a built-in concave reflector R. The working principle of the comb-type electrostatically driven vertical micromirror optical switch is similar to that of the cantilever type. Both achieve the movement of the emitted light by the repulsion or attraction between the fixed electrode and the electrostatically driven vertical micromirror. The angle of the emitted light is deflected by the different curvature positions of the concave or convex electrostatically driven vertical micromirror or reflector, thereby achieving angle control of the light in the horizontal direction.

[0079] For the comb-type electrostatically driven vertical micromirror optical switch chip, when manufacturing using silicon-on-insulator wafer and sacrificial layer process, after manufacturing according to the above steps (1) to (3), the wafer after deep etching and metallization is immersed in hydrofluoric acid to remove the buried oxide layer silicon dioxide in the silicon-on-insulator wafer to obtain a suspended comb structure.

[0080] For the optical switch chip of the comb-type electrostatically driven vertical micromirror, when the silicon-glass bonding silicon deep etching release process is used for manufacturing, the suspension groove is first etched on the back side of the wafer, and then the back side of the wafer is anoly bonded to a glass wafer containing potassium and sodium ions. Then the front side of the wafer is thinned and polished, and then the manufacturing is carried out according to the above steps (1) to (3) to obtain the comb-type electrostatically driven vertical micromirror.

[0081] In practical implementation, the movement direction of a cantilever electrostatically driven vertical micromirror (MSM) is a deflection around an anchor point, causing the incident light to deflect along the z-axis. This necessitates adding multiple cantilever MSMs to level the light. In contrast, a comb-type MSM moves horizontally, ensuring the outgoing and incoming light remain at the same horizontal height. However, the manufacturing process for cantilever MSMs is simpler, requiring only deep etching of a single-crystal silicon wafer. The manufacturing process for comb-type MSMs is more complex, requiring sacrificial layer technology or silicon-on-glass (SOG) deep etching-release technology to achieve the suspended comb structure. Both cantilever and comb-type MSM structures have their advantages, and the choice should be based on actual needs.

[0082] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0083] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A high-temperature electrostatically driven vertical micromirror optical switch chip for on-chip integration, characterized in that, The device includes a wafer and a fixed electrode thereon, an electrostatically driven vertical micromirror, and a reflector. The electrostatically driven vertical micromirror can be a cantilever electrostatically driven vertical micromirror or a comb-type electrostatically driven vertical micromirror. The electrostatically driven vertical micromirror or the reflector can be flat, convex, or concave. The movement of the emitted light is achieved by the repulsion or attraction between the fixed electrode and the electrostatically driven vertical micromirror. The movement direction of the cantilever electrostatically driven vertical micromirror is deflection around the anchor point, and the movement direction of the comb-type electrostatically driven vertical micromirror is translational along the horizontal direction. The concave or convex electrostatically driven vertical micromirror or the reflector can deflect the angle of the emitted light to achieve optical signal switching. The fabrication process of the optical switch chip includes: Manufacturing steps for fixed electrodes, vertical micromirrors, and reflectors: The fixed electrodes, vertical micromirrors, and reflectors are formed by deep etching on the upper surface of the wafer. The vertical sidewalls formed by deep etching are planarized and polished. The planarization etching of the vertical sidewalls after deep etching is performed by immersing the fixed electrodes, vertical micromirrors, and reflectors in a mixed solution of potassium hydroxide or tetramethylammonium hydroxide and isopropanol. Silicon dioxide layer deposition step: A silicon dioxide insulating layer is deposited on the surface of the wafer, fixed electrode, vertical micromirror and mirror using inductively coupled plasma chemical vapor deposition or plasma-enhanced chemical vapor deposition. Electrode and interconnect manufacturing steps: deposit metal layers on the surfaces of the fixed electrode, vertical micromirror and reflector, and form interconnects, metallized fixed electrodes, metallized vertical micromirrors and metallized reflectors by peeling.

2. The optical switch chip according to claim 1, characterized in that, It includes a combination of one or more sets of fixed electrodes and electrostatically driven vertical micromirrors, wherein one or more of the electrostatically driven vertical micromirrors are planar, convex or concave. The reflector can be segmented or integral, and can be any one or any combination of a plane reflector, a convex reflector, and a concave reflector.

3. The optical switch chip according to claim 1, characterized in that, If the electrostatically driven vertical micromirror is a cantilever electrostatically driven vertical micromirror, then multiple combinations of the fixed electrodes and electrostatically driven vertical micromirrors are provided to level the light.

4. The optical switch chip according to claim 1, characterized in that, The electrode and interconnect manufacturing steps include: Photoresist is applied using a spray coating method, and then exposed and developed to form electrode and interconnect patterns. Deposited metal layer; The photoresist and excess metal layers are removed by stripping to form lead interconnects, metallized fixed electrodes, metallized cantilever electrostatically driven vertical micromirrors, and metallized reflectors.

5. The optical switch chip according to claim 4, characterized in that, The material of the metal layer is titanium / gold, aluminum, chromium / gold, titanium / platinum / gold, titanium / nickel / gold, titanium / copper, chromium / copper, or titanium / nickel / copper.

6. The optical switch chip according to claim 1, characterized in that, If the electrostatically driven vertical micromirror has a concave or convex surface, then in the manufacturing steps of the fixed electrode, vertical micromirror, and reflector, a shallow fixed electrode, a shallow vertical micromirror with a convex or concave surface, and a shallow reflector are formed by photolithography and etching, and the electrode and interconnect manufacturing steps include: A thick photoresist is coated on the upper surface of the wafer, and then exposed and developed to form a base pattern. Based on the deep silicon etching of the base pattern, a base is formed below the shallow fixed electrode, the shallow cantilever electrostatically driven vertical micromirror, and the shallow reflector. Photoresist is applied using a spray coating method, and then exposed and developed to form electrode and interconnect patterns. Deposited metal layer; The photoresist and excess metal layers are removed by stripping to form interconnects, metallized fixed electrodes, metallized cantilever electrostatically driven vertical micromirrors with convex or concave surfaces, and metallized reflectors.

7. The optical switch chip according to claim 1, characterized in that, If the electrostatically driven vertical micromirror is a comb-type electrostatically driven vertical micromirror, then after the electrode and interconnect manufacturing steps, the wafer is immersed in hydrofluoric acid to remove the buried oxide layer silicon dioxide in the silicon-on-insulator wafer or the sacrificial layer deposited on the single crystal silicon wafer, to obtain a suspended comb structure.

8. The optical switch chip according to claim 1, characterized in that, If the electrostatically driven vertical micromirror is a comb-type electrostatically driven vertical micromirror, then before the manufacturing steps of the fixed electrode, vertical micromirror, and reflector, a suspension groove is etched on the back side of the wafer, the back side of the wafer is anodicly bonded to a glass wafer containing potassium and sodium ions, and the front side of the wafer is thinned and polished.

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