Electromagnetic electrostatic double-driven copperr filter chip and preparation method thereof

Abstract

The application provides an electromagnetic electrostatic double-drive Coppe filter chip and a preparation method thereof, and relates to the fields of optoelectronic chips and semiconductor technologies.The filter chip comprises a movable mirror body, a fixed mirror body, a permanent magnet, a PCB circuit board and a spacing layer.A first reflecting mirror, a first detection electrode, a second detection electrode, a first drive electrode and a second drive electrode are arranged on the end face of the movable mirror body.The first detection electrode and the first drive electrode are arranged on one side of the first reflecting mirror, and the second detection electrode and the second drive electrode are arranged on the other side of the first reflecting mirror.A permanent magnet slot for embedding the permanent magnet is arranged on the other end face of the movable mirror body.The application can overcome the problems of the single-drive Coppe filter chip, such as nonlinear modulation, limited tuning range and poor monochromaticity.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic chips and semiconductor technology, and more specifically, to an electromagnetic-electrostatic dual-drive EPA filter chip and its fabrication method. Background Technology

[0002] The epoch-filter chip is a tunable spectral filter chip that combines traditional epoch-filters with micro-electro-mechanical systems (MEMS) technology. Its basic structure consists of two flat plates with semi-transparent and semi-reflective mirrors, one movable and one fixed, separated by a specific distance to form an epoch-filter interference cavity. When incident light enters the epoch-filter cavity, if the cavity length is an integer multiple of half the wavelength of the incident light, a stable resonance can be formed within the cavity, generating multi-beam interference and transmitting it out with high energy, while other wavelengths of light gradually attenuate within the cavity. By driving the movable mirror using MEMS micro-drive technology, the length of the epoch-filter cavity changes, thus achieving tunable spectral filtering. Miniaturized, lightweight, and intelligent spectral detection systems built based on epoch-filter chips can be integrated with small platforms such as UAVs, seekers, and smart mobile devices, showing broad application prospects in weapon guidance, target detection, industrial monitoring, environmental protection, and remote sensing.

[0003] Existing enamel filter chips typically employ piezoelectric, thermal, electrostatic, and electromagnetic actuation to adjust the enamel cavity, each exhibiting distinct characteristics. Piezoelectric-driven enamel filter chips utilize the inverse piezoelectric effect to change the enamel cavity, thereby achieving spectral modulation. They are applicable to enamel filter chips across different wavelength bands, but material limitations prevent them from being mass-produced at the wafer level. Thermally driven enamel filter chips use the thermoelectric effect to change the enamel cavity length, requiring prolonged heating and cooling, resulting in slow response and high power consumption. Electrostatically driven enamel filter chips use electrostatic force for spectral tuning, offering advantages such as strong process compatibility and high device integration. However, the tuning range is limited by the "pull-in" phenomenon inherent in electrostatic driving methods.

[0004] Existing enamel filter chips are typically fabricated using two methods: bulk fabrication and surface fabrication. Surface fabrication usually involves fabricating a MEMS enamel filter chip on a single substrate using processes such as thin film deposition, photolithography, etching, and sacrificial layers. Surface-fabricated enamel filter chips offer advantages such as low acceleration sensitivity and high processing quality. However, due to the presence of thin film stress, this process is difficult to fabricate large-aperture enamel filter chips. Furthermore, the thin film bending caused by applying large driving forces prevents the achievement of wide-range modulation. Bulk fabrication enamel filter chips, due to the accumulation of processing stress and error factors at various stages of the manufacturing process, are prone to exhibiting non-parallelism between the two mirrors of the enamel cavity, resulting in poor monochromaticity of the chip's spectral filtering. Summary of the Invention

[0005] The problem solved by this invention is how to overcome the problems of nonlinear modulation, limited tuning range and poor monochromaticity of Fabry-Perot filter chips in single-drive mode.

[0006] To address the aforementioned problems, this invention provides an electromagnetic-electrostatic dual-drive Fabry-Perot filter chip, comprising a movable mirror body, a fixed mirror body, a permanent magnet, a PCB circuit board, and a spacer layer.

[0007] The movable mirror body has a first reflecting mirror, a first detection electrode, a second detection electrode, a first driving electrode, and a second driving electrode on its end face. The first detection electrode and the first driving electrode are located on one side of the first reflecting mirror, and the second detection electrode and the second driving electrode are located on the other side of the first reflecting mirror. The other end face of the movable mirror body has a permanent magnet groove for embedding the permanent magnet.

[0008] A second reflecting mirror, a first fixed electrode, and a second fixed electrode are provided on the end face of the fixed mirror body. The second reflecting mirror is located in the moving direction of the first reflecting mirror. The first fixed electrode is located in the moving direction of the first detection electrode and the first driving electrode. The second fixed electrode is located in the moving direction of the second detection electrode and the second driving electrode. The first fixed electrode and the second fixed electrode are respectively located on both sides of the second reflecting mirror.

[0009] The movable mirror body and the fixed mirror body are bonded together by a bonding layer, and an enamel interference cavity is formed between the first reflector and the second reflector; at least two cantilever beams for supporting the movable mirror body are etched on the movable mirror body near the bonding layer.

[0010] The movable mirror body, on the side away from the bonding layer, is encapsulated on the PCB circuit board via the spacer layer.

[0011] In the above structure, the first reflecting mirror, the first and second detection electrodes, the first driving electrode and the second driving electrode are fabricated on the movable mirror body; the second reflecting mirror, the first fixed electrode and the second fixed electrode are fabricated on the fixed mirror body; the movable mirror body and the fixed mirror body are bonded together by a bonding layer; the first and second reflecting mirrors form an enamel interference cavity; the first and second detection electrodes, together with the first and second fixed electrodes, form two sets of detection capacitor groups; the first and second driving electrodes, together with the first and second fixed electrodes, form driving electrode groups; a permanent magnet is embedded on the back of the movable mirror body to form a bare chip; the bare chip is packaged onto a PCB circuit board through a spacer layer. The cantilever beam is a hollow structure etched into the movable mirror body. The function of the cantilever beam is to deform during driving to support the first reflecting mirror in the middle of the movable mirror body to move towards the second reflecting mirror on the fixed mirror body. Using electromagnetic drive as the main drive and electrostatic drive as the auxiliary drive, combined with an electrostatic closed-loop feedback control mechanism, not only can bidirectional wide-amplitude linear modulation filtering be achieved, but the problem of poor monochromaticity during the operation of the filter chip can also be solved, improving the spectral output accuracy.

[0012] Furthermore, the PCB circuit board includes a drive control circuit and a drive coil corresponding to the permanent magnet;

[0013] The drive control circuit is used to apply current or voltage to the drive coil. The drive coil generates an electromagnetic field that interacts with the magnetic field of the permanent magnet to generate an electromagnetic force, which drives the movable mirror to move and adjust the length of the enamel interference cavity.

[0014] Furthermore, the bonding layer includes a first bonding layer and a second bonding layer; the first bonding layer is bonded to the movable mirror body, and the second bonding layer is bonded to the fixed mirror body;

[0015] The first bonding layer and the second bonding layer are adopted by any one of polymer bonding, gold-silicon bonding, gold-gold bonding, and silicon-glass bonding.

[0016] Furthermore, the first and second reflectors are fabricated using MEMS technology, employing either a metal reflector or a dielectric multilayer film reflector.

[0017] Furthermore, the first detection electrode, the second detection electrode, the first driving electrode, the second driving electrode, the first fixed electrode, and the second fixed electrode are fabricated using MEMS deposition technology, employing any one of metal thin film, ITO thin film, or a combination of metal thin film and ITO thin film.

[0018] An electromagnetic-electrostatic dual-drive EPA filter chip and its fabrication method include the following steps:

[0019] S1: Select a substrate for fabricating the movable mirror. When the working band of the filter chip is ultraviolet, visible and near-infrared, use glass or quartz substrate; when the working band of the filter chip is infrared, use silicon, zinc sulfide, sapphire or gallium arsenide infrared substrate. Clean and dry the substrate.

[0020] S2: Fabricate a first detection electrode, a second detection electrode, a first driving electrode, and a second driving electrode on a movable mirror substrate;

[0021] S3: Fabricate the first reflecting mirror on the movable mirror substrate using MEMS technology;

[0022] S4: Use an etching process to fabricate a permanent magnet groove on the movable mirror substrate, with the etching depth being less than the thickness of the movable mirror substrate; fabricate a first bonding layer on the movable mirror substrate;

[0023] S5: The corresponding area of ​​the movable mirror substrate is etched through by an etching process to create a cantilever beam;

[0024] S6: Select a substrate for fabricating the fixed mirror. When the working band of the filter chip is ultraviolet, visible and near-infrared, it is a glass or quartz substrate; when the working band of the filter chip is infrared, it is a silicon, zinc sulfide, sapphire or gallium arsenide infrared substrate. Clean and dry the substrate.

[0025] S7: Fabricate the first and second fixed electrodes on the fixed mirror substrate;

[0026] S8: Fabricate a second mirror on a fixed mirror substrate using MEMS technology; fabricate a second bonding layer on the fixed mirror substrate, and bond the second bonding layer to the first bonding layer.

[0027] Furthermore, the thickness of the bonding layer after bonding in step S8 is... d 3:

[0028] d3=mλ m / 2+d1+d2;

[0029] in, λm This indicates the center wavelength of the EPA filter chip. m Indicates the level of interference. d1 This indicates the thickness of the first reflecting mirror. d 2 indicates the thickness of the second reflecting mirror;

[0030] The movable mirror body and the fixed mirror body are bonded through a first bonding layer and a second bonding layer using polymer bonding, gold-silicon bonding, gold-gold bonding or silicon-glass bonding processes.

[0031] Furthermore, it also includes the following steps:

[0032] S9: Embed the permanent magnet into the permanent magnet slot of the movable mirror to form a single bare chip;

[0033] S10: The bare chip is packaged onto the PCB circuit board through a spacer layer, which is used to control the distance between the permanent magnet and the PCB circuit board.

[0034] The present invention employing the above technical solution has the following beneficial effects:

[0035] This invention enables bidirectional wide-range linear modulation filtering using a proposed electromagnetic-electrostatic dual-drive enamel filter chip. Electromagnetic drive is the primary driver, with electrostatic drive as an auxiliary driver, combined with an electrostatic closed-loop feedback control mechanism. This solves the problem of poor monochromaticity during filter chip operation and improves spectral output accuracy. High-quality fabrication of the enamel filter chip is achieved through wafer-level integrated mass production using MEMS bulk fabrication technology. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention;

[0037] Figure 2 The working principle of the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 1 ;

[0038] Figure 3 The working principle of the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 2 ;

[0039] Figure 4 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 1 ;

[0040] Figure 5 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 2 ;

[0041] Figure 6 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 3 ;

[0042] Figure 7 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 4 ;

[0043] Figure 8MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 5 ;

[0044] Figure 9 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 6 ;

[0045] Figure 10 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 7 ;

[0046] Figure 11 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 8 ;

[0047] Figure 12 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 9 ;

[0048] Figure 13 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 10 ;

[0049] Figure 14 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 10 one;

[0050] Figure 15 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 10 two;

[0051] Figure 16 MEMS wafer-level fabrication process flow for the electromagnetic-electrostatic dual-drive EPA filter chip provided in Embodiment 1 of the present invention Figure 10 three;

[0052] Figure 17 This is a flowchart of the electromagnetic-electrostatic dual-drive EPA filter chip and its fabrication method provided in Embodiment 2 of the present invention.

[0053] Explanation of reference numerals in the attached figures:

[0054] 1-Modible mirror body, 101-Permanent magnet slot, 102-Cantilever beam, 2-Fixed mirror body, 3-First reflecting mirror, 4-Second reflecting mirror, 5-Bonding layer, 501-First bonding layer, 502-Second bonding layer, 6-First detection electrode, 7-Second detection electrode, 8-First driving electrode, 9-Second driving electrode, 10-First fixed electrode, 11-Second fixed electrode, 12-Permanent magnet, 13-Spacer layer, 14-PCB circuit board, 15-Drive control circuit, 16-Drive coil. Detailed Implementation

[0055] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0056] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0057] Example 1

[0058] This embodiment provides an electromagnetic / electrostatic dual-drive EPA filter chip, such as... Figure 1 As shown, it includes a movable mirror body 1, a fixed mirror body 2, a permanent magnet 12, a PCB circuit board 14, and a spacer layer 13;

[0059] A first reflecting mirror 3, a first detection electrode 6, a second detection electrode 7, a first driving electrode 8, and a second driving electrode 9 are provided on the end face of the movable mirror body 1. The first detection electrode 6 and the first driving electrode 8 are located on one side of the first reflecting mirror 3, and the second detection electrode 7 and the second driving electrode 9 are located on the other side of the first reflecting mirror 3. A permanent magnet groove 101 for embedding a permanent magnet 12 is provided on the other end face of the movable mirror body 1.

[0060] A second reflecting mirror 4, a first fixed electrode 10, and a second fixed electrode 11 are provided on the end face of the fixed mirror body 2. The second reflecting mirror 4 is located in the moving direction of the first reflecting mirror 3, the first fixed electrode 10 is located in the moving direction of the first detection electrode 6 and the first driving electrode 8, and the second fixed electrode 11 is located in the moving direction of the second detection electrode 7 and the second driving electrode 9. The first fixed electrode 10 and the second fixed electrode 11 are respectively located on both sides of the second reflecting mirror 4.

[0061] The movable mirror 1 and the fixed mirror 2 are bonded together by a bonding layer 5, and an enamel interference cavity is formed between the first reflecting mirror 3 and the second reflecting mirror 4; at least two cantilever beams 102 for supporting the movable mirror 1 are etched on the movable mirror 1 near the bonding layer 5.

[0062] The movable mirror body 1 is encapsulated on the PCB circuit board 14 on the side away from the bonding layer 5 through the spacer layer 13.

[0063] The PCB circuit board 14 includes a drive control circuit 15 and a drive coil 16 corresponding to the permanent magnet 12.

[0064] The drive control circuit 15 is used to apply current or voltage to the drive coil 16. The drive coil 16 generates an electromagnetic field that interacts with the magnetic field of the permanent magnet 12 to generate an electromagnetic force, which drives the movable mirror 1 to move and adjust the length of the enamel interference cavity.

[0065] Specifically, the PCB circuit board 14 is made using printed circuit board technology. It contains a drive control circuit 15, which is used to apply current or voltage to the drive coil 16, and at the same time calculate the difference between the two sets of detection capacitors and apply compensation voltage. The drive coil 16 contained therein is used to generate an electromagnetic field to drive the permanent magnet 12 to move the movable mirror 1.

[0066] See Figure 2 and Figure 3 The working principle of the electromagnetic-electrostatic dual-drive enamel filter chip is as follows: Current is supplied to the drive coil 16 through the drive control circuit 15 in the PCB circuit board 14. The drive coil 16 generates an electromagnetic field, which interacts with the magnetic field of the permanent magnet 12 to generate an electromagnetic force, thereby driving the movable mirror 1 to move and change the length of the enamel cavity, thereby changing the transmission wavelength. When the movable mirror 1 moves to the equilibrium position, capacitances C1 and C2 are generated between the detection capacitor group composed of the first detection electrode 6 and the first fixed electrode 10 and the detection capacitor group composed of the second detection electrode 7 and the second fixed electrode 11, respectively. The drive control circuit 15 calculates the difference between C1 and C2. If C1 = C2, the movable mirror 1 and the fixed mirror 2 are parallel and no compensation voltage needs to be applied. If C1 ≠ C2, it indicates that the movable mirror 1 and the fixed mirror 2 are not parallel. At this time, the drive control circuit 15 applies compensation voltages V1 and V2 to the drive electrode pair composed of the first drive electrode 8 and the first fixed electrode 10 and the drive electrode pair composed of the second drive electrode 9 and the second fixed electrode 11, respectively, according to the difference between C1 and C2, to fine-tune the enamel cavity and achieve balance, thereby forming a closed-loop feedback control mechanism.

[0067] By controlling the direction of the input current, the direction of the magnetic field generated by the drive coil 16 can be changed, thus enabling bidirectional wide-amplitude modulation of the Fabry-Perot filter chip. By linearly adjusting the magnitude of the drive current, and based on the proportional relationship between the magnitude of the Ampere force and the magnitude of the current, linear changes in the electromagnetic force can be achieved. Combined with a closed-loop feedback control mechanism, precise and controllable linear modulation filtering of the Fabry-Perot filter chip can be realized.

[0068] The bonding layer 5 includes a first bonding layer 501 and a second bonding layer 502; the first bonding layer 501 is bonded to the movable mirror body 1, and the second bonding layer 502 is bonded to the fixed mirror body 2.

[0069] The first bonding layer 501 and the second bonding layer 502 are adopted by any one of polymer bonding, gold-silicon bonding, gold-gold bonding, and silicon-glass bonding.

[0070] The first reflector 3 and the second reflector 4 are fabricated using MEMS technology and can be either metal reflectors or dielectric multilayer film reflectors.

[0071] The first detection electrode 6, the second detection electrode 7, the first driving electrode 8, the second driving electrode 9, the first fixed electrode 10, and the second fixed electrode 11 are fabricated using MEMS deposition technology, employing any one of metal thin film, ITO thin film, or a combination of metal thin film and ITO thin film.

[0072] Specifically, the chip in this embodiment operates in the long-wave infrared band, with the center wavelength of the operating band being... λ m Designed for 10 μm The first-stage interference filter peak value is used. ( m＝1 ) Therefore, the initial enamel cavity length ( m λ m / 2) Designed as 5 μm .

[0073] The movable mirror body 1 is made of 500mm thick material. μm The permanent magnet groove 101 and cantilever beam 102 are fabricated using a 4-inch dual-polished zone fused silicon wafer and deep reactive ion etching. The cantilever beam 102 is a hollow structure etched into the movable mirror body 1. The function of the cantilever beam 102 is to deform during driving to support the movement of the mirror portion in the middle of the movable mirror body 1. The permanent magnet groove 101 is an annular groove with an etching depth of 200 μm. μm The inner and outer diameters of the groove are 11. mm and 13 mm .

[0074] Fixed mirror body 2 uses a thickness of 500 μm Fabricated using a four-inch dual-polished zone fused silicon wafer, the first reflector 3 and the second reflector 4 are five-layered. Ge / ZnS The film-based distributed Bragg reflector, fabricated using electron beam evaporation, has a refractive index ratio of [missing value]. Ge：ZnS =4:2.2, single layer Ge Thickness 625 nm Single layer ZnS Thickness is 1136 nm Therefore, the thicknesses of the movable mirror 3 and the fixed mirror 4 are d1 = d2 = 4.147. μm。

[0075] The thickness of the bonded layer after bonding is d 3=mλ m / 2+d1+d2; where, λ m This indicates the center wavelength of the EPA filter chip. m Indicates the level of interference. d 1 represents the thickness of the first reflecting mirror. d 2 indicates the thickness of the second reflector. The bonding layer 5 is fabricated using a gold-silicon bonding process. The first bonding layer 501 is a gold film, and the second bonding layer 502 is silicon; the center wavelength is designed according to the filter chip. λ m =10 μm Job level m =1. Thickness of the movable reflector 3 and the fixed reflector 4 d 1 = d2 = 4.147 μm The final thickness of the bonded layer 5 after bonding can be calculated. d 3=mλ m / 2+d1+d2=13.294 μm。 The first detection electrode 6 and the second detection electrode 7, the first driving electrode 8 and the second driving electrode 9, the first fixed electrode 10 and the second fixed electrode 11 are 500. nm The thick gold film is made using electron beam evaporation.

[0076] Permanent magnet 12 is made of sintered neodymium iron boron material, grade N45, and its dimensions are: inner diameter × outer diameter × thickness = 11. mm ×13 mm ×0.5 mm It is assembled into the permanent magnet groove 101 of the movable mirror body 1 by embedding, and the fit between it and the permanent magnet groove 101 is a clearance fit.

[0077] Spacer layer 8 has a thickness of 1 mm The gasket, made of ABS and manufactured by 3D printing, is encapsulated between the movable mirror 1 and the PCB circuit board 14. It is mainly used to precisely control the distance between the permanent magnet 12 and the PCB circuit board 14.

[0078] PCB board 14 is a 16-layer printed circuit board with an internal copper trace width of 0.25 mm. mm It contains a drive control circuit 15, which applies current to the drive coil 16 to generate an electromagnetic field to drive the permanent magnet 12 to move, and calculates the capacitance of the detection capacitor to control the application of compensation voltage to the drive electrode.

[0079] like Figure 4 Select a thickness of 500mm for high flatness. μmThe four-inch dual-polished zone melting silicon wafer is used to process the movable mirror body 1. The silicon wafer surface oxide layer is removed by hydrofluoric acid solution, the silicon wafer is cleaned with deionized water, and then dried with nitrogen gas.

[0080] like Figure 5 Electron beam evaporation was used to deposit 500 μm of silicon onto a zone-melted silicon substrate. nm A gold film is formed by photolithography to create a photoresist mask, followed by etching of the gold film with a gold etching solution. After removing the photoresist and cleaning, the first detection electrode 6, the second detection electrode 7, the first driving electrode 8, and the second driving electrode 9 are formed.

[0081] like Figure 6 Photolithography was performed on a zone-melting silicon substrate, and electron beam evaporation was used to sequentially deposit Ge / ZnS / Ge / ZnS / Ge = 625 μm thick material. nm / 1136 nm / 625 nm / 1136 nm / 625 nm The first mirror 3 is fabricated by dissolving and stripping the photoresist in an acetone solution after the five-layer distributed Bragg reflector is assembled. Its total thickness is [not specified]. d 1 = 4.147 μm。

[0082] like Figure 7 Photolithography is performed on the back of the silicon wafer, and deep reactive ion etching is used to etch 200 nm. μm The permanent magnet slot 101 is fabricated with an outer diameter of 13 mm. mm The inner diameter is 11 mm。

[0083] like Figure 8 Photolithography is performed on the silicon wafer, followed by electron beam evaporation deposition of 300 μm. nm A thick gold film is placed in acetone to melt and peel off the photoresist, completing the fabrication of the first bonding layer 501.

[0084] like Figure 9 Photolithography was performed on the substrate of the movable mirror 1, and then deep reactive ion etching was used to etch through the corresponding areas of the substrate to fabricate the cantilever beam 102 structure. This completes the fabrication of the movable mirror 1.

[0085] like Figure 10 Select a thickness of 500mm for high flatness. μm The four-inch dual-polished zone melting silicon wafer is used to process the fixed mirror body 2. The silicon wafer surface oxide layer is removed by hydrofluoric acid solution, the silicon wafer is cleaned with deionized water, and then dried with nitrogen gas.

[0086] like Figure 11 Electron beam evaporation was used to deposit 500 μm of material on the substrate of the fixed mirror body 2. nmA gold film is formed by photolithography to create a photoresist mask on the gold film, followed by etching with a gold etching solution. After removing the photoresist and cleaning, the first fixed electrode 10 and the second fixed electrode 11 are formed.

[0087] like Figure 12 Photolithography was performed on the substrate of the fixed mirror body 2, and electron beam evaporation was used to sequentially deposit thicknesses. Ge / ZnS / Ge / ZnS / Ge＝ 625 nm / 1136 nm / 625 nm / 1136 nm / 625 nm The five-layer distributed Bragg reflector was then immersed in an acetone solution to melt and peel off the photoresist, completing the fabrication of the second reflector 4. Its total thickness is... d 2 = 4.147 μm。

[0088] like Figure 13 Plasma chemical vapor deposition was used to deposit 13 on the fixed mirror substrate 2. d A silicon film with a thickness of 2 is formed, and photolithography is performed on the silicon film. Excess silicon film is removed by deep reactive ion etching to complete the fabrication of the second bonding layer 502. This completes the fabrication of the fixed mirror body 2.

[0089] like Figure 14 The movable mirror 1 and the fixed mirror 2 are bonded at the wafer level using a gold-silicon bonding process. The first bonding layer 501 and the second bonding layer 502 are formed under hot pressing to form the bonding layer 5, the final thickness of which is... d 3 = m λ m / 2+ d 1+ d 2 = 13.294 μm。 The bonded movable mirror 1 and fixed mirror 2 are diced and separated into individual chips.

[0090] like Figure 15 The permanent magnet 12 is embedded in the permanent magnet slot 101 of the movable mirror body 1 to form a single bare chip.

[0091] like Figure 16 The bare chip and spacer layer 13 are then encapsulated onto the PCB circuit board 14 to complete the chip fabrication.

[0092] This invention enables bidirectional wide-range linear modulation filtering using a proposed electromagnetic-electrostatic dual-drive enamel filter chip. Electromagnetic drive is the primary driver, with electrostatic drive as an auxiliary driver, combined with an electrostatic closed-loop feedback control mechanism. This solves the problem of poor monochromaticity during filter chip operation and improves spectral output accuracy. High-quality fabrication of the enamel filter chip is achieved through wafer-level integrated mass production using MEMS bulk fabrication technology.

[0093] Example 2

[0094] This embodiment provides an electromagnetic-electrostatic dual-drive EPA filter chip and its fabrication method, such as... Figure 17 As shown, this method includes the following steps:

[0095] S1: Select a substrate for fabricating the movable mirror. When the working band of the filter chip is ultraviolet, visible and near-infrared, use glass or quartz substrate; when the working band of the filter chip is infrared, use silicon, zinc sulfide, sapphire or gallium arsenide infrared substrate. Clean and dry the substrate.

[0096] S2: Fabricate a first detection electrode, a second detection electrode, a first driving electrode, and a second driving electrode on a movable mirror substrate;

[0097] S3: Fabricate the first reflecting mirror on the movable mirror substrate using MEMS technology;

[0098] S4: Use an etching process to fabricate a permanent magnet groove on the movable mirror substrate, with the etching depth being less than the thickness of the movable mirror substrate; fabricate a first bonding layer on the movable mirror substrate;

[0099] S5: The corresponding area of ​​the movable mirror substrate is etched through by an etching process to create a cantilever beam;

[0100] S6: Select a substrate for fabricating the fixed mirror. When the working band of the filter chip is ultraviolet, visible and near-infrared, it is a glass or quartz substrate; when the working band of the filter chip is infrared, it is a silicon, zinc sulfide, sapphire or gallium arsenide infrared substrate. Clean and dry the substrate.

[0101] S7: Fabricate the first and second fixed electrodes on the fixed mirror substrate;

[0102] S8: Fabricate a second mirror on a fixed mirror substrate using MEMS technology; fabricate a second bonding layer on the fixed mirror substrate, and bond the second bonding layer to the first bonding layer.

[0103] In step S8, the thickness of the bonding layer after bonding is... d 3:

[0104] d3=mλm / 2+d1+d2;

[0105] in, λm This indicates the center wavelength of the EPA filter chip. m Indicates the level of interference. d1 This indicates the thickness of the first reflecting mirror. d 2 indicates the thickness of the second reflecting mirror;

[0106] The movable mirror body and the fixed mirror body are bonded through a first bonding layer and a second bonding layer using polymer bonding, gold-silicon bonding, gold-gold bonding or silicon-glass bonding processes.

[0107] This also includes the following steps:

[0108] S9: Embed the permanent magnet into the permanent magnet slot of the movable mirror to form a single bare chip;

[0109] S10: The bare chip is packaged onto the PCB circuit board through a spacer layer, which is used to control the distance between the permanent magnet and the PCB circuit board.

[0110] This method enables bidirectional wide-range linear modulation filtering using an electromagnetic-electrostatic dual-drive EPA filter chip, with electromagnetic drive as the primary driver and electrostatic drive as the auxiliary driver, combined with an electrostatic closed-loop feedback control mechanism. This solves the problem of poor monochromaticity during filter chip operation and improves spectral output accuracy. High-quality fabrication of the EPA filter chip is achieved through wafer-level integrated mass production using MEMS bulk fabrication technology.

[0111] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. An electromagnetic-electrostatic dual-drive enamel filter chip, characterized in that, It includes a movable mirror body (1), a fixed mirror body (2), a permanent magnet (12), a PCB circuit board (14), and a spacer layer (13). The movable mirror body (1) is provided with a first reflector (3), a first detection electrode (6), a second detection electrode (7), a first driving electrode (8), and a second driving electrode (9) on its end face. The first detection electrode (6) and the first driving electrode (8) are located on one side of the first reflector (3), and the second detection electrode (7) and the second driving electrode (9) are located on the other side of the first reflector (3). The other end face of the movable mirror body (1) is provided with a permanent magnet groove (101) for embedding the permanent magnet (12). The fixed mirror body (2) is provided with a second reflector (4), a first fixed electrode (10) and a second fixed electrode (11) on its end face. The second reflector (4) is located in the moving direction of the first reflector (3). The first fixed electrode (10) is located in the moving direction of the first detection electrode (6) and the first driving electrode (8). The second fixed electrode (11) is located in the moving direction of the second detection electrode (7) and the second driving electrode (9). The first fixed electrode (10) and the second fixed electrode (11) are located on both sides of the second reflector (4). The movable mirror (1) and the fixed mirror (2) are bonded together by a bonding layer (5), and an enamel interference cavity is formed between the first reflector (3) and the second reflector (4); at least two cantilever beams (102) for supporting the movable mirror (1) are etched on the movable mirror (1) near the bonding layer (5). The movable mirror (1) is encapsulated on the PCB circuit board (14) on the side away from the bonding layer (5) through the spacer layer (13); The PCB circuit board (14) includes a drive control circuit (15) and a drive coil (16) corresponding to the permanent magnet (12). The drive control circuit (15) is used to apply current or voltage to the drive coil (16). The drive coil (16) generates an electromagnetic field that interacts with the magnetic field of the permanent magnet (12) to generate an electromagnetic force, which drives the movable mirror (1) to move and adjust the length of the enamel interference cavity. Among them, the detection capacitor group composed of the first detection electrode (6) and the first fixed electrode (10) and the detection capacitor group composed of the second detection electrode (7) and the second fixed electrode (11) respectively generate capacitors C1 and C2; the driving control circuit (15) calculates the difference between capacitor C1 and capacitor C2. If capacitor C1 is equal to capacitor C2, the movable mirror (1) and the fixed mirror (2) are parallel and no compensation voltage needs to be applied; if capacitor C1 is not equal to capacitor C2, it indicates that the movable mirror (1) and the fixed mirror (2) are not parallel. The driving control circuit (15) applies compensation voltages V1 and V2 to the driving electrode pair composed of the first driving electrode (8) and the first fixed electrode (10) and the driving electrode pair composed of the second driving electrode (9) and the second fixed electrode (11) respectively according to the difference between capacitor C1 and capacitor C2, so as to fine-tune the enamel cavity and achieve balance, thereby forming a closed-loop feedback control mechanism.

2. The electromagnetic-electrostatic dual-drive EPA filter chip according to claim 1, characterized in that, The bonding layer (5) includes a first bonding layer (501) and a second bonding layer (502); the first bonding layer (501) is bonded to the movable mirror body (1), and the second bonding layer (502) is bonded to the fixed mirror body (2); The first bonding layer (501) and the second bonding layer (502) are adopted by any one of polymer bonding, gold-silicon bonding, gold-gold bonding, and silicon-glass bonding.

3. The electromagnetic-electrostatic dual-drive EPA filter chip according to claim 1, characterized in that, The first reflector (3) and the second reflector (4) are fabricated using MEMS technology, and can be either metal reflectors or dielectric multilayer film reflectors.

4. The electromagnetic-electrostatic dual-drive EPA filter chip according to claim 1, characterized in that, The first detection electrode (6), the second detection electrode (7), the first driving electrode (8), the second driving electrode (9), the first fixed electrode (10), and the second fixed electrode (11) are fabricated by MEMS deposition process, using any one of metal thin film, ITO thin film, or a combination of metal thin film and ITO thin film.

5. The method for fabricating an electromagnetic-electrostatic dual-drive EPA filter chip as described in any one of claims 1 to 4, characterized in that, Including the following steps: S1: Select a substrate for fabricating the movable mirror. When the working band of the filter chip is ultraviolet, visible and near-infrared, use glass or quartz substrate; when the working band of the filter chip is infrared, use silicon, zinc sulfide, sapphire or gallium arsenide infrared substrate. Clean and dry the substrate. S2: Fabricate a first detection electrode, a second detection electrode, a first driving electrode, and a second driving electrode on a movable mirror substrate; S3: Fabricate the first reflecting mirror on the movable mirror substrate using MEMS technology; S4: Use an etching process to fabricate a permanent magnet groove on the movable mirror substrate, with the etching depth being less than the thickness of the movable mirror substrate; fabricate a first bonding layer on the movable mirror substrate; S5: The corresponding area of ​​the movable mirror substrate is etched through by an etching process to create a cantilever beam; S6: Select a substrate for fabricating the fixed mirror. When the working band of the filter chip is ultraviolet, visible and near-infrared, it is a glass or quartz substrate; when the working band of the filter chip is infrared, it is a silicon, zinc sulfide, sapphire or gallium arsenide infrared substrate. Clean and dry the substrate. S7: Fabricate the first and second fixed electrodes on the fixed mirror substrate; S8: Fabricate a second mirror on a fixed mirror substrate using MEMS technology; fabricate a second bonding layer on the fixed mirror substrate, and bond the second bonding layer to the first bonding layer.

6. The method for fabricating an electromagnetic-electrostatic dual-drive EPA filter chip according to claim 5, characterized in that, The thickness of the bonding layer after bonding in step S8 is: d 3: d 3= mλ m / 2+ d 1+ d 2； in, λ m This indicates the center wavelength of the EPA filter chip. m Indicates the level of interference. d 1 represents the thickness of the first reflecting mirror. d 2 indicates the thickness of the second reflecting mirror; The movable mirror body and the fixed mirror body are bonded through a first bonding layer and a second bonding layer using polymer bonding, gold-silicon bonding, gold-gold bonding or silicon-glass bonding processes.

7. The method for fabricating an electromagnetic-electrostatic dual-drive EPA filter chip according to claim 5, characterized in that, It also includes the following steps: S9: Embed the permanent magnet into the permanent magnet slot of the movable mirror to form a single bare chip; S10: The bare chip is packaged onto the PCB circuit board through a spacer layer, which is used to control the distance between the permanent magnet and the PCB circuit board.

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