A method for manufacturing a MEMS infrared light source

Abstract

The present invention belongs to the field of optoelectronic technology, and specifically relates to a method for manufacturing a MEMS infrared light source. The manufacturing method is used to manufacture a MEMS infrared light source containing a special cavity and a reflective layer between a substrate and a support layer. The method comprises the following steps: (1) mask processing of the substrate; (2) preparation of an etching window; (3) anisotropic etching; (4) preparation of a reflective layer; (5) primary polishing; (6) preparation of a sacrificial layer; (7) secondary polishing; (8) preparation of a support layer; (9) preparation of a heating electrode layer; (10) preparation of a heating electrode pad; (11) preparation of an infrared emission layer; (12) preparation of a sacrificial window; and (13) removal of the sacrificial layer. The process principle is: first, a pit is etched, then the pit is filled with a sacrificial layer, then various functional layers are generated on a plane, and finally a sacrificial window is opened to connect the pit, the sacrificial layer is removed, and the product manufacturing is completed. The product produced by the present invention can solve the problems of low photoelectric conversion efficiency and low product yield of existing MEMS infrared light sources.

Description

Technical Field

[0001] The present invention belongs to the field of optoelectronic technology, and in particular relates to a method for manufacturing a MEMS infrared light source. Background Art

[0002] Infrared sensing technology has been widely used in fields such as air quality monitoring, temperature monitoring, industrial process control, space surveillance, information and communications, medicine, and the military. Infrared light sources are key components of infrared sensing technology, with commonly used wavelengths of 3-5 microns and 8-14 microns. Traditional thermal infrared light sources, such as incandescent lamps, have low electro-optical conversion efficiency and poor modulation characteristics. Infrared diodes with wavelengths between 3 and 5 microns have low luminous efficiency and low output power, limiting their application. Quantum cascade infrared lasers can emit high-intensity narrowband infrared laser light, but their efficiency is also low and their manufacturing cost is high. Microelectromechanical Systems (MEMS) infrared light sources, manufactured using MEMS technology, are a new type of thermal infrared light source. They feature high electro-optical conversion efficiency, a compact size, and low energy consumption. Their spectrum easily covers the 2-20 micron range and features a fast modulation frequency. These MEMS infrared light sources have been widely used in the infrared sensing field and have become a trendsetting technology for infrared light sources.

[0003] A conventional MEMS infrared light source includes a substrate, a support layer is provided on the substrate, the support layer and the substrate are connected using a four-sided clamped structure, and a heating electrode layer is provided on the support layer. By energizing the heating electrode layer to generate Joule heat, the heating electrode layer is heated to a specific temperature (determined according to the required infrared emission wavelength and radiation amount), thereby generating infrared radiation. MEMS infrared light sources mainly dissipate heat through two pathways: heat conduction and infrared radiation. Among them, heat conduction is the heat transfer from the heating electrode layer through the substrate. This part of heat transfer should be reduced as much as possible to improve the electro-optical conversion efficiency of the MEMS infrared light source and reduce heating power consumption. Infrared radiation is the core of the work of the MEMS infrared light source and needs to be enhanced. Therefore, it is necessary to significantly reduce the heat conduction of the heating electrode layer. Usually, the substrate under the heating electrode layer is hollowed out to reduce the heat conduction of the substrate. Infrared radiation can be enhanced by selecting a material with high emissivity to make the heating electrode layer or adding an infrared emission layer with higher infrared emissivity on the surface of the heating electrode layer.

[0004] The infrared radiation of the MEMS infrared light source is mainly emitted from two directions: one is radiated outward from the top of the heating electrode layer. This part of the infrared radiation can be used by the infrared sensor and needs to be strengthened; the other is radiated from the heating electrode layer through the support layer to the hollow part of the substrate. This part of the infrared radiation will be absorbed by the packaging material and substrate after the MEMS infrared light source is packaged and cannot be effectively utilized. It is a waste of energy and needs to be reduced as much as possible or even eliminated.

[0005] Existing MEMS infrared light sources significantly reduce their thermal conductivity through substrate hollowing technology, improving their electro-optical conversion efficiency and reducing heating power consumption. By introducing materials or microstructures with high infrared emissivity above the heating electrode layer, the infrared emission capability is enhanced, thereby reducing the heating power consumption of the MEMS infrared light source. At the same time, a good understanding of the selection of heating electrode layers has also been achieved. However, most existing MEMS infrared light sources have not yet effectively solved the problem of utilizing the infrared energy radiated from the heating electrode layer through the support layer to the hollowed-out portion of the substrate, resulting in a huge waste of infrared radiation energy and increasing the heating power consumption of the MEMS infrared light source.

[0006] In order to suppress the energy loss caused by the radiation diffusing from the bottom of the heating electrode layer, some technicians have proposed an improved solution of adding a reflective layer to the bottom surface of the support layer of the MEMS infrared light source (such as China Invention Patent Application Publication No. CN114249292A). This solution uses the reflective layer to reflect the infrared rays radiated from the heating electrode layer through the support layer to the substrate hollowed out, and then radiates upward through the heating electrode layer. However, while this type of solution solves the loss of infrared radiation, it also creates new technical problems. For example, a reflective layer that is tightly bonded to the support layer will increase the heat capacity of the entire infrared light-emitting film layer, thereby increasing the heat loss of the MEMS light source. At the same time, the design of the reflective layer and the support layer also increases the risk of the reflective layer falling off due to the difference in thermal expansion coefficients that is easy to occur during the switching stage of the light source, thereby reducing the service life of the light source. Summary of the Invention

[0007] In order to solve the problems of low photoelectric conversion efficiency and low product yield in existing MEMS infrared light sources, the present invention provides a method for manufacturing a MEMS infrared light source, which can produce a new type of MEMS infrared light source that overcomes the disadvantages of traditional light sources.

[0008] The present invention is achieved by adopting the following technical solutions:

[0009] The manufacturing method of the MEMS infrared light source provided by the present invention is used to manufacture a MEMS infrared light source comprising a substrate, a support layer, a heating electrode layer and an infrared emission layer; and containing a cavity of special shape between the substrate and the support layer, and a reflective layer of specific shape distributed in the cavity.

[0010] The manufacturing method includes the following process steps:

[0011] (1) Mask processing of substrate:

[0012] A substrate is provided, and a preset amount of mask layer material is deposited on the surface of the substrate to be processed to form a required etching mask layer.

[0013] (2) Preparation of corrosion window:

[0014] According to the preset window size and shape, the photolithography technology is used to remove part of the mask layer on the surface to be processed to form an etching window on the substrate. The area exposed below the etching window is the substrate area that needs to be etched.

[0015] (3) Anisotropic corrosion:

[0016] The substrate is chemically etched by an anisotropic etching process to form a pit in an etching window region of the substrate that is recessed toward the inside of the substrate and has a gradually decreasing diameter.

[0017] (4) Preparation of reflective layer:

[0018] A physical vapor deposition process is used to deposit a preset amount of reflective layer material in the pits on the surface of the substrate to form the required reflective layer.

[0019] (5) One-time polishing:

[0020] The surface of the substrate to be processed is polished to remove the surface coating in areas other than the pits on the substrate surface, including the etching mask layer material and the reflective layer material.

[0021] (6) Preparation of sacrificial layer:

[0022] The pits in the substrate are filled with a sacrificial layer material that can be selectively removed by any means.

[0023] (7) Secondary polishing:

[0024] The surface to be processed of the substrate filled with the sacrificial layer material is subjected to a secondary polishing process so that the sacrificial layer material in the pit remains flush with the surrounding substrate surface.

[0025] (8) Preparation of support layer:

[0026] A required supporting layer is generated on the surface of the substrate containing the sacrificial layer, and the supporting layer completely covers the substrate and the sacrificial layer below.

[0027] (9) Preparation of heating electrode layer:

[0028] The required heating electrode layer is prepared on the surface of the support layer. The heating electrode layer is located above the corresponding pit in the substrate. The left and right sides of the heating electrode layer completely cover the pit, while the front and back sides are located in the area inside the pit and do not cover the pit.

[0029] (10) Preparation of heating electrode pads:

[0030] Two parallel long strip heating electrode pads are prepared above the heating electrode layer and do not exceed the distribution area of the heating electrode layer. The distribution areas of the two heating electrode pads are separated from or circumscribed to the enclosed area of the upper opening of the pit.

[0031] (11) Preparation of infrared emission layer:

[0032] The infrared emission layer is formed on the heating electrode layer inside the heating electrode pad. The infrared emission layer is located in the area where the four ends of the heating electrode pad are connected.

[0033] (12) Preparation of sacrificial window:

[0034] The supporting layer material is etched by photolithography technology, and at least one penetrating sacrificial window is processed in a specific area without damaging the heating electrode layer and the infrared emission layer above, so as to expose the sacrificial layer material in the pit below.

[0035] (13) Removal of sacrificial layer:

[0036] According to the specificity of the selected sacrificial material, specific technical means are used to selectively remove all sacrificial layer materials filled in the pit to form the required cavity structure; thereby preparing the required MEMS infrared light source.

[0037] As a further improvement of the present invention, in step (1), the substrate material is silicon, and the silicon (100) crystal plane is used as the surface to be processed. The material of the mask layer is selected from any one of silicon oxide, silicon nitride, Cr, Au, Pt and NiCr alloy.

[0038] As a further improvement of the present invention, in step (3), any one of TMAH aqueous solution, KOH aqueous solution, NaOH aqueous solution, mixed aqueous solution of ethylenediamine and catechol, and NH4OH aqueous solution is used as the anisotropic etching solution; the corrosion depth is controlled to be 1-50 μm.

[0039] As a further improvement of the present invention, in step (4), the reflective layer is a single metal coating made of one material selected from Ag, Au, Cu, and Al. Alternatively, the reflective layer is a composite metal coating made by depositing multiple materials selected from Ag, Au, Cu, and Al layer by layer. Alternatively, a dielectric film Bragg coating is prepared as the desired reflective layer.

[0040] As a further improvement of the present invention, in step (6), the sacrificial layer material is selected from one of SiO2, phosphosilicate glass, silica gel, polyimide, SU-8, polydimethylsiloxane (PDMS), gelatin, polyethylene glycol, polyparaxylene, and benzocyclobutene.

[0041] Accordingly, in step (13), a solvent or solution capable of directionally corroding the sacrificial layer material is used as a selective etching liquid for immersion treatment. The etching liquid diffuses into the cavity through the sacrificial window, completely removing the sacrificial layer material in the cavity. After the sacrificial layer is removed, the product is also cleaned and dried.

[0042] As a further improvement of the present invention, the polishing treatment in step (5) adopts wet etching or chemical mechanical polishing; and in step (7), the polishing treatment is carried out by dry etching or chemical mechanical polishing.

[0043] As a further improvement of the present invention, the support layer in step (8) is generated by physical vapor deposition or chemical vapor deposition process; the generated support layer is a single coating composed of silicon oxide or silicon nitride, or a multilayer composite coating composed of silicon oxide or silicon nitride deposited layer by layer in a preset order.

[0044] As a further improvement of the present invention, in step (9), the heating electrode layer is generated by physical vapor deposition or chemical vapor deposition process; the material of the heating electrode layer is selected from any one of Pt, Mo, NiCr alloy, polycrystalline silicon, SiC, Cu, W, HfB2, PtSi and SnO2.

[0045] To improve the interfacial adhesion strength between the support layer and the heating electrode layer, in a more optimized embodiment of the present invention, a transition layer made of a specific material can be first deposited on the surface of the support layer; and then the desired heating electrode layer is formed. The transition layer can be selected from any one of Ti, Cr, and Ni, depending on the materials used for the heating electrode layer and support layer.

[0046] As a further improvement of the present invention, in step (10), the heating electrode pad is electrically connected to the heating electrode layer, and the material for preparing the heating electrode pad is selected from any one of AlSi alloy, Au, Al, NiCr alloy, and NiV alloy.

[0047] As a further improvement of the present invention, in step (11), the required infrared emission layer is prepared by using a material with high infrared emissivity. The thickness of the prepared infrared emission layer is 50-1000nm. The materials with high infrared emissivity include NiCr alloy, TiN, TiAlN, amorphous carbon, SiC, NiCrO compound, ZrO2, HfO2, La 1-x Ca x A mixture of any one or more of CrO3 (0≤x≤0.5) and carbon nanotubes.

[0048] In particular, in the optimized solution of the present invention, the emitting surface of the processed infrared emitting layer has a rough surface structure.

[0049] As a further improvement of the present invention, when the prepared infrared emission layer is conductive, a step of preparing an isolation layer is added between steps (9) and (10). After the isolation layer is prepared, the heating electrode pad preparation step of step (10) needs to first remove the isolation layer in a portion of the area used to set the heating electrode pad by a photolithography stripping method, so that the heating electrode pad is electrically connected to the heating electrode layer below; and in step (11), the infrared emission layer is located on the upper surface of the isolation layer.

[0050] Specifically, the isolation layer is formed by physical vapor deposition or chemical vapor deposition, and the material is one or a combination of any two of silicon oxide, silicon nitride, and aluminum oxide.

[0051] As a further improvement of the present invention, a step of preparing a protective layer is added between step (11) and step (12), and the prepared protective layer completely covers the upper surfaces of the infrared emitting layer, the infrared electrode layer and the support layer.

[0052] The protective layer is formed by physical vapor deposition or chemical vapor deposition process, and the material is selected from any one or more combinations of silicon oxide, silicon nitride, aluminum oxide, and hafnium oxide.

[0053] The technical solution provided by the present invention has the following beneficial effects:

[0054] The preparation method provided by this invention can be used to produce a special MEMS infrared light source comprising a substrate, a support layer, a heating electrode layer, and an infrared emitting layer; the light source also contains a specially shaped cavity between the substrate and the support layer, within which a reflective layer of a specific shape is distributed. This unique MEMS light source structure is difficult to manufacture, and conventional lamination processes are difficult to fabricate. The present invention has developed a manufacturing process specifically for this new product.

[0055] The MEMS infrared light source manufactured using this process improves the structure of the substrate of traditional light sources by creating a specially shaped pit above the substrate. This creates a cavity between the pit and the support layer, located below the heating electrode layer and the infrared emission layer. A complete reflective layer is also formed on the wall of the pit. This specially structured MEMS infrared light source can simultaneously suppress ineffective heat conduction and energy consumption generated by ineffective infrared radiation, reducing the device's heat capacity and significantly improving its photoelectric conversion efficiency.

[0056] Furthermore, the uniquely structured MEMS infrared light source provided by the present invention offers strong thermal stability and structural strength, and its lifespan and various weather resistance properties are also enhanced. Compared to traditional devices, this device offers significant performance advantages and is suitable for large-scale commercial deployment. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a schematic diagram of the longitudinal cross-section structure of a MEMS infrared light source prepared using the substrate hollowing technology in the background technology.

[0058] Figure 2 It is a schematic diagram of the longitudinal cross-section structure of a MEMS infrared light source in the background art in which a reflective layer is provided at the bottom of a hollowed-out substrate.

[0059] Figure 3 This is a schematic diagram of the overall structure of the MEMS infrared light source provided in Example 1 of the present invention.

[0060] Figure 4 This is a schematic structural diagram of a substrate containing pits of the MEMS infrared light source provided in Example 1 of the present invention.

[0061] Figure 5 This is a schematic cross-sectional structural diagram of the MEMS infrared light source provided in Example 1 of the present invention.

[0062] Figure 6 This is a layered exploded diagram of the specific structure of the MEMS infrared light source provided in Example 1 of the present invention.

[0063] Figure 7 This is a schematic cross-sectional structural diagram of a MEMS infrared light source including a transition layer provided in Example 1 of the present invention.

[0064] Figure 8 This is a schematic cross-sectional structural diagram of a MEMS infrared light source with an isolation layer provided in Example 1 of the present invention.

[0065] Figure 9 This is a schematic cross-sectional structural diagram of a MEMS infrared light source with a protective layer provided in Example 1 of the present invention.

[0066] Figure 10 A method for manufacturing the MEMS infrared light source in Example 1 is provided in Example 2 of the present invention.

[0067] Figure 11 for Figure 5 Schematic diagram of the cross-sectional structure of the MEMS infrared light source from the perspective of both sides. The sacrificial window inside the supporting layer can be seen from the longitudinal section from this side.

[0068] Figure 12 This is a schematic diagram of the product structure obtained after the "mask processing of the substrate" step in Example 2 is completed.

[0069] Figure 13 This is a schematic diagram of the product structure obtained after the "corrosion window preparation" step in Example 2 is completed.

[0070] Figure 14Schematic diagram of the product structure obtained after the "anisotropic etching" step in Example 2.

[0071] Figure 15 This is a schematic diagram of the product structure obtained after the "reflective layer preparation" step in Example 2 is completed.

[0072] Figure 16 This is a schematic diagram of the product structure obtained after the "one-time polishing" step in Example 2.

[0073] Figure 17 Schematic diagram of the product structure obtained after the "sacrificial layer preparation" step in Example 2 is completed.

[0074] Figure 18 This is a schematic diagram of the product structure obtained after the "secondary polishing" step in Example 2.

[0075] Figure 19 This is a schematic diagram of the product structure obtained after the "support layer preparation" step in Example 2 is completed.

[0076] Figure 20 This is a schematic diagram of the product structure obtained after the "heating electrode layer preparation" step in Example 2 is completed.

[0077] Figure 21 This is a schematic diagram of the product structure obtained after the "isolation layer preparation" step in Example 2 is completed.

[0078] Figure 22 This is a schematic diagram of the product obtained after the "heating electrode pad preparation" step in Example 2 is completed.

[0079] Figure 23 This is a schematic diagram of the product structure obtained after the "infrared emission layer preparation" step in Example 2 is completed.

[0080] Figure 24 This is a schematic diagram of the product structure obtained after the "protective layer preparation" step in Example 2 is completed.

[0081] Figure 25 This is a schematic diagram of the product structure obtained after the "sacrificial window preparation" step in Example 2.

[0082] Figure 26 Schematic diagram of the product structure obtained after the "sacrificial layer removal" step in Example 2.

[0083] The following are marked in the figure:

[0084] 100, pit; 101, substrate; 201, mask; 301, reflective layer; 401, sacrificial layer; 501, support layer; 601, heating electrode layer; 701, isolation layer; 801, heating electrode pad; 901, infrared emitting layer; 1001, protective layer; 1002, sacrificial window; 5011, transition layer. DETAILED DESCRIPTION

[0085] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0086] Example 1

[0087] Figure 1 and Figure 2 It is a schematic diagram of the longitudinal cross-sectional structure of the MEMS infrared light source in the two existing solutions mentioned in the background technology. These two technical solutions are the same as traditional infrared light sources, and both include a substrate 101, a support layer 501, a heating electrode layer 601, an isolation layer 701, an infrared emission layer 901 and a heating electrode pad 801. This type of laminated structure device can be manufactured by a process of sequentially generating different functional layers on the substrate 101. Among them, the substrate 101 is the basis for generating the various functional layers above, and serves to provide stable attachment of each layer and provide good support. The support layer 501 is an intermediate layer between the substrate 101 and the heating electrode layer 601, and plays a good supporting role. In particular, when the substrate 101 undergoes special etching processing, the support layer 501 can provide good support for the various functional layers above, and evenly disperse the load generated by the compressive stress of each part above.

[0088] The heating electrode layer 601 is connected to the heating electrode pad 801, which is used to connect wires to power the heating electrode. The heating electrode layer 601 is a functional layer that converts electrical energy into its own internal energy. When conductive, the heating electrode layer 601 rapidly heats up and generates infrared radiation. The infrared emitting layer 901 is a functional layer made of a material with ultra-high infrared emissivity. When heated, it emits the received internal energy as infrared radiation.

[0089] Since the main function of the heating electrode layer 601 is to generate infrared radiation and heat the infrared emission layer 901 that is in direct contact with the upper portion by heat conduction, the infrared emission layer 901 can maintain an emission state. However, since the support layer 501 and the bottom surface of the infrared electrode layer are also in direct contact, the heat generated by the heating electrode layer will also be conducted to the support layer 501 and the substrate 101. For the MEMS infrared light source, the energy consumption of this part of the heat conducted to the support layer 501 and the substrate 101 is not converted into effective infrared radiation, which belongs to the ineffective power consumption of the device (a type of loss). The ineffective power consumption of the device will significantly reduce the photoelectric conversion efficiency of the MEMS light source. On the other hand, the infrared radiation generated by the infrared emission layer 901 will radiate both upward and downward. The upward radiation belongs to the effective radiation emitted, while the downward radiation cannot be effectively modulated and applied, which belongs to the ineffective radiation (a type of loss). The generated ineffective radiation is another important reason for reducing the photoelectric conversion efficiency of the device.

[0090] Figure 1 The technical solution provided is mainly based on a multi-layer stacked MEMS infrared light source, in which the position corresponding to the infrared emission layer 901 at the bottom of the substrate 101 is hollowed out. The contact area between the hollowed-out substrate 101 and the support layer 501 is reduced, and the volume and mass of the substrate 101 are greatly reduced. This can effectively reduce the energy loss caused by heat conduction when the device is working, that is, reduce a type of loss of the device. At the same time, since the hollowed-out part is located on the bottom surface of the substrate 101, it will not affect the processing and forming of the functional layers above. However, it should be noted that since the substrate 101 plays a supporting role in the device processing process, the substrate 101 must be hollowed out by photolithography, etching, etc. after all functional layers are formed.

[0091] Figure 2 The technical solution proposed by the inventor of this case is Figure 1 This solution is a further improvement. The main improvement is the addition of a reflective layer 301 to the hollowed-out portion of the bottom surface of substrate 101. Reflective layer 301 is made of a material with high infrared reflectivity. Therefore, reflective layer 301 can reflect downward infrared radiation generated by the infrared emitting layer 901 above, converting some ineffective radiation into effective radiation. This, in turn, reduces the device's Type II losses. Figure 2 While this technical solution reduces the second-class loss of the device, it also has some disadvantages. Figure 2 The details of the disadvantages of the solution will be specifically explained later when introducing the advantages of the improved solution provided by this embodiment.

[0092] Specifically, in this embodiment Figure 1 and Figure 2On the basis of the corresponding technical solution, a new type of MEMS infrared light source with improved photoelectric conversion efficiency is further provided. The overall structure of the light source provided in this embodiment is as follows Figure 3 As shown, the MEMS infrared light source includes a substrate 101, a support layer 501, a heating electrode layer 601, an infrared emission layer 901 stacked in sequence from bottom to top; and two heating electrode pads 801 electrically connected to the heating electrode layer 601. It should be emphasized that Figure 3 The text and images in the following text of this embodiment mainly use rectangular light sources as examples when introducing this case. However, the shape of the light source is not a limiting technical feature of this embodiment, and the technical solution provided by this embodiment is not limited to any one shape. The MEMS infrared light source with improved photoelectric conversion efficiency can be a rectangular light source, a circular light source, or even an elliptical, long strip, or any other irregular shape.

[0093] The main difference between the technical solution provided by this embodiment and the existing solution is that: Figure 4 As shown, the upper surface of the substrate 101 of the MEMS infrared light source of this embodiment is provided with a downwardly concave pit 100, which includes a horizontal bottom surface and a sloped sidewall. The substrate 101 is a four-side clamped structure connected to the upper support layer 501, and a cavity structure is formed between the two. Figure 5 It can be seen that in the MEMS infrared light source provided in this embodiment, the enclosed area of the upper opening of the pit 100 covers the infrared emission layer 901. In other words, the distribution area of the upper opening of the pit 100 can completely cover the infrared emission layer 901 above it. It can be understood that the entire infrared emission layer 901 in the light source of this embodiment is "suspended" above the pit 100.

[0094] Please combine Figure 6 In the substrate 101 of the MEMS infrared light source provided in this embodiment, the enclosed area of the upper opening of the pit 100 is located on the inner side of the two heating electrode pads 801, and the distribution area of the enclosed area of the upper opening of the pit 100 along the extension direction of at least one end of the heating electrode pad 801 exceeds the length range of the heating electrode pad 801. In layman's terms, taking a rectangular light source as an example, the length of the pit 100 along the extension direction parallel to the heating electrode pad 801 is longer than the infrared emission layer 901 (and the heating electrode layer 601) above. The width of the pit 100 perpendicular to the extension direction of the heating electrode pad 801 is shorter than the infrared emission layer 901 (and the heating electrode layer 601) below. When the light source adopts other shapes, this limitation should be met, that is, the pit 100 must be "sandwiched" between the two heating electrode pads 801, but slightly longer than the heating electrode pad 801.

[0095] At the same time, if Figure 5As shown, the area of the support layer 501 of the MEMS infrared light source provided in this embodiment is larger than the upper opening of the pit 100 and the heating electrode layer 601. Figure 3 and Figure 6 As shown, at least one penetrating sacrificial window 1002 is provided in the support layer 501, and the sacrificial window 1002 is connected to the pit 100 in the substrate 101 below. The distribution position of the sacrificial window 1002 is tangent to or separated from the distribution position of the heating electrode layer 601. Specifically, the support layer 501 completely "covers" the pit 100 on the substrate 101. And the heating electrode layer 601 just covers the support layer 501 directly opposite the pit 100. At the same time, a sacrificial window 1002 is provided in the support layer 501 that is connected to the pit 100 below, and the sacrificial window 1002 must be distributed at a position on the support layer 501 that will not be blocked by the heating electrode layer 601 and the infrared emission layer 901.

[0096] In the MEMS infrared light source provided in this embodiment, a complete reflective layer 301 is provided on the bottom surface and sidewalls of the pit 100 of the substrate 101. The reflective layer 301 is made of a material with high reflectivity for infrared rays in the wavelength range of 2-14 microns.

[0097] The following describes in detail the working principle and performance advantages of the MEMS light source product in combination with the above technical features of the MEMS light source provided in this embodiment.

[0098] First, the light source provided in this embodiment has and Figure 2 The "hollowed" structure of the scheme is similar to the pit 100 in this case. Therefore, the substrate 101 of this case can also reduce the heat capacity of the MEMS infrared light source and reduce the heat conduction from the heating electrode layer 601 to the substrate 101. This reduces the loss of the device. However, the pit 100 of this case is similar to the Figure 2 The method of "hollowing out" the substrate 101 is different. In particular, the pit 100 in this case is located above the substrate 101, which forms a cavity between the substrate 101 and the support layer 501. The functions of the cavity structure in this embodiment include the following two points: 1. The cavity can effectively block the downward heat conduction path of the assembly composed of the heating electrode layer 601 and the support layer 501, and play the first effect of reducing heat radiation. 2. The gas medium in the cavity is equivalent to a "thermal blanket" composed of a poor thermal conductor, which prevents heat from being transferred to the substrate 101 and dissipated from the larger surface of the substrate 101.

[0099] Secondly, the structure of the pit 100 in this case is a shape with a large upper opening and a small lower opening, as shown in FIG. Figure 4-6As shown, the longitudinal cross-section of the pit 100 is roughly in the shape of a "water channel". Considering that the wall and bottom of the pit 100 will generate the required reflective layer 301, the sloped wall of the pit 100 has at least the following advantages:

[0100] (1) The reflective layer 301 material is primarily formed by sputtering or evaporation. The sloped walls of the pit 100 facilitate better deposition of the reflective layer 301 material. This improves the dispersion and continuity of the reflective layer 301 within the pit 100, resulting in a uniform and complete reflective layer 301. This enhances the reflective layer 301's reflective effect on infrared radiation.

[0101] (2) The horizontal bottom surface of the pit 100 is equivalent to a plane reflector, which can completely reflect the bottom radiation of the infrared emission layer 901 above to the top of the infrared emission layer 901.

[0102] (3) The sloped wall of the pit 100 is just above the pressure surface of the support layer 501, which is also the bearing support point of the heating electrode pad 801. Figure 5 The sloped wall is equivalent to a trapezoidal "bank" with a small upper base and a large lower base, providing excellent pressure and impact resistance. This can make the MEMS infrared light source device have strong shock and pressure resistance, and improve the product life.

[0103] (4) The pit 100 needs to be generated by various processes such as anisotropic etching or photolithography during processing. This special shape of the pit 100 is also compatible with the process characteristics of chemical etching and laser etching, making it very easy to process and thus reducing the production cost of the product.

[0104] Furthermore, in the technical solution for the MEMS infrared light source provided in this embodiment, the distribution area of the pit 100 (i.e., the distribution area of the reflective layer 301) is precisely "contracted" inside the two heating electrode pads 801. This allows the heating electrode pads 801 to overlap the slope of the pit 100, maintaining a good support effect. Furthermore, the infrared emission layer 901 between the heating electrode pads 801 can be completely "suspended" above the pit 100. This allows all bottom-directed radiation from the infrared emission layer 901 to reach the emission layer within the pit 100, thereby increasing the reflectivity of the bottom-directed radiation and minimizing the power loss of Type II.

[0105] One point needs to be emphasized: in the technical solution provided in this embodiment, the substrate 101 has a cavity formed by a pit 100 between it and the support layer 501; the reflective layer 301 disposed on the wall of the cavity has the following advantages: because the reflective layer 301 is isolated from the heating area of the MEMS light source by the cavity, when the MEMS is frequently switched on and off, the temperature of the reflective layer 301 is relatively low and stable. Therefore, the thermal expansion between the substrate 101 and the reflective layer 301 is not significant, and the reflective layer 301 does not undergo significant deformation or fall off. In other words, in the solution of this embodiment, the reflective layer 301 has good heat resistance. Even if the device is used for a long time, the reflective layer 301 is not easily damaged, the device has a long service life, and the device can maintain its optimal photoelectric conversion performance to the greatest extent.

[0106] And for Figure 2 As for the existing solution, when the MEMS infrared light source is frequently turned on and off, the reflective layer 301 is in direct contact with the support layer 501 (equivalent to direct contact with the heating area of the MEMS). At this time, the temperature of the reflective layer 301 changes dramatically during use, and the substrate 101 and the reflective layer 301 may undergo different degrees of thermal expansion, which in turn leads to a deterioration of the interface adhesion between the two, and in severe cases, damage to the reflective layer 301. Figure 2 The reflective layer 301 is located below the substrate 101. Once the reflective layer 301 is damaged, it may partially fall off, destroying the uniformity and integrity of the reflective layer 301, and lose its infrared radiation reflection function, thereby reducing the photoelectric conversion efficiency of the MEMS infrared light source.

[0107] At the same time, one of the important functions of the cavity and substrate 101 hollowing process is to reduce the heat capacity of the device, thereby improving the photoelectric conversion efficiency of the device. (Note: Heat capacity refers to the ability of an object to absorb and store heat energy; the higher the heat capacity, the lower the temperature rise when absorbing the same amount of heat energy. Heat capacity is related to the volume / mass of the object, as well as the type of material and other properties.) In this case, the reflective layer 301 is located under the cavity and does not contact the supporting layer 501, so it has almost no effect on the heat capacity of the device. Figure 2 In the solution, the reflective layer 301 is in direct contact with the supporting layer 501, and the reflective layer 301 increases the heat capacity of the device. This is not conducive to improving the photoelectric conversion efficiency of the device.

[0108] Finally, the sacrificial window 1002 of a special shape and position reserved on the support layer 501 in this embodiment primarily facilitates product processing. As is well known, each functional layer above the substrate 101 is actually a micron- or nanometer-scale coating or thin film. Therefore, these functional layers cannot be grown directly on the surface of the substrate 101 with the pits 100; otherwise, each functional layer would also have pits and would not be flat. Therefore, the pits 100 can only be processed after the functional layers are formed. However, etching a pit 100 in the "center" of the device after the functional layers are formed is technically impractical.

[0109] To address this issue, the present invention has designed a special production process specifically for producing the MEMS infrared light source with the special structure provided in this embodiment. A key technical approach of this embodiment's processing technology is to use a material with certain specificity that can be selectively removed through a specific method as a sacrificial layer 401. The sacrificial layer 401 is pre-filled into the machined recess 100. After the functional layers above the recess 100 are formed, the sacrificial layer 401 material is removed from the recess 100. The reserved sacrificial window 1002 on the support layer 501 is used to remove the sacrificial layer 401 material from the recess 100.

[0110] In particular, the sacrificial window 1002 designed in this embodiment communicates with the recess 100 in the underlying substrate 101, facilitating removal of the sacrificial layer 401 material within the recess 100. It also needs to be tangential to or spaced apart from the distribution of the heating electrode layer 601, thereby ensuring that the integrity of the functional layers above is not damaged and that the functions of the functional layers above are not affected. Furthermore, the sacrificial window 1002 should not be blocked or obstructed by the functional layers above.

[0111] In practical applications, there is at least one sacrificial window 1002, and the sacrificial window 1002 can be a through hole of any shape, such as a circular hole, a strip, etc. In the optimal solution, the sacrificial window 1002 should be symmetrically arranged on the support layer 501, located on both sides of the heating electrode layer 601. This can ensure that the support layer 501 remains balanced under stress and strain, thereby improving production yield and service life. Generally speaking, the optimal solution for the MEMS infrared light source provided in this embodiment is also to maintain good structural symmetry in the design of the overall structure (including each functional layer). This is to improve the structural strength, stress resistance and various performances of the device.

[0112] In the MEMS infrared light source provided in this embodiment, the depth of the cavity structure is 1-50. The cavity of the device can achieve the best technical effect under the conditions of this depth range. When the cavity depth is lower than the preferred range, the substrate 101 is almost equivalent to a non-pit 100, and the support layer 501 and the substrate 101 are very close, and the above-mentioned technical effect cannot be achieved. When the cavity depth is greater than the preferred range, the depth of the cavity is too large, which increases the difficulty of processing, and the reflection effect of the reflective layer 301 on infrared radiation will deteriorate.

[0113] In this embodiment, the reflective layer 301 can be a metal-plated thin film made from any one of Ag, Au, Cu, and Al. Alternatively, a dielectric film Bragg reflector 301 can be used. Alternatively, a multilayer composite film composed of any number of single metal-plated thin films stacked in a specified order can be used. Ag, Au, Cu, and Al all have high infrared reflectivity. A dielectric film Bragg reflector is a common laminated optical film composed of a sequence of high- and low-refractive-index dielectric materials. Through film layer design, it can strongly reflect specific wavelengths of infrared light or a wide spectrum of infrared light, and can also serve as the reflective film in this embodiment.

[0114] Considering the varying costs of different materials, the cost of Ag and Au reflective layers 301 is significantly higher than that of Cu and Al. Therefore, in practical applications, different materials can be layered on substrate 101 as needed to form a composite reflective layer 301 thin film. For example, Cu can be used as the base of reflective layer 301, with a thinner Au coating formed on the upper surface to form the desired reflective layer 301. The composite reflective layer 301 not only maintains a high infrared radiation reflectivity but also achieves better technical results in terms of production costs and comprehensive performance of the MEMS infrared light source, such as material strength, toughness, and wear resistance.

[0115] The substrate 101 in this embodiment includes silicon and other materials that can be used as infrared light source substrates 101, such as quartz, glass, sapphire, etc. When silicon is used as the required substrate 101 material, the silicon (100) surface is usually used as the working surface for forming the pit 100 and various functional layers. In this case, anisotropic etching of silicon can be easily used to achieve an inverted trapezoidal (large opening, small bottom) pit 100 shape.

[0116] In this embodiment, support layer 501 is constructed from a single material, silicon oxide or silicon nitride, or a multilayer composite material composed of alternating layers of silicon oxide and silicon nitride. Both silicon oxide and silicon nitride are inorganic, non-metallic materials characterized by high strength, hardness, poor thermal conductivity, insulation, high temperature resistance, and corrosion resistance. They are well-suited for use as support layer 501 in MEMS light sources.

[0117] The infrared emitting layer 901 in the MEMS light source of this embodiment is made of a material with high infrared emissivity and has a thickness of 50-1000 nm. The material with high infrared emissivity includes a mixture of any one or more of NiCr alloy, TiN, TiAlN, amorphous carbon, SiC, NiCrO compound, ZrO2, HfO2, La1-xCaxCrO3 (0≤x≤0.5), and carbon nanotubes.

[0118] In particular, the emitting surface of the infrared emitting layer 901 of this embodiment has a rough surface structure. The rough surface structure improves the infrared emitting capability of the MEMS infrared light source.

[0119] In this embodiment, the material of the heating electrode layer 601 is any one of Pt, Mo, NiCr alloy, polysilicon, SiC, Cu, W, HfB2, PtSi and SnO2; the above materials are all existing materials used to manufacture resistive heating units. The heating electrode layer 601 prepared from these materials can convert electrical energy into internal energy more efficiently to generate heat after being energized.

[0120] like Figure 7 As shown, in a more optimized technical solution of the present invention, a transition layer 5011 can be added between the heating electrode layer 601 and the support layer 501 to improve the interfacial adhesion between the two. The transition layer 5011 can be selected from any one of Ti, Cr, and Ni, depending on the materials used for the heating electrode layer 601 and the support layer 501. For example, when the heating electrode layer 601 is made of Pt and the support layer 501 is made of SiO2, an ultra-thin Cr coating can be added to the upper surface of the support layer 501 during the manufacturing process, thereby significantly improving the interfacial adhesion strength between the two. This prevents displacement between the heating electrode layer 601 and the support layer 501 during use, thereby improving the overall performance of the product.

[0121] In this embodiment, the two heating electrode pads 801 are parallel to each other and electrically connected to the upper surface of the heating electrode layer 601; the infrared emission layer 901 is located between the two heating electrode pads 801. The heating electrode pads 801 are made of any one of AlSi alloy, Au, Al, NiCr alloy, and NiV alloy. The main function of the heating electrode pads 801 is to introduce directional electron migration on the heating electrode layer 601, thereby allowing the heating electrode layer 601 to generate heat. Therefore, the material of the heating electrode pads 801 used in this embodiment is a material with high electrical conductivity, high thermal stability, and high solderability.

[0122] like Figure 8As shown, in a more optimized solution of this embodiment, the heating electrode layer 601 and the infrared emitting layer 901 are further provided with an isolation layer 701 for blocking the electrical conduction effect between the two. The isolation layer 701 is made of silicon oxide, silicon nitride, aluminum oxide or any combination thereof.

[0123] The isolation layer 701 is usually only used when the material of the infrared emission layer 901 is also conductive. If the infrared emission layer 901 is produced using insulating materials, such as ZrO2, HfO2, La1-xCaxCrO3 (0≤x≤0.5), etc., there is no need to set the isolation layer 701 between the heating electrode layer 601 and the infrared emission layer 901. The working mechanism of the isolation layer 701 is as follows: When the infrared emission layer 901 is made of conductive material, if it is not electrically isolated from the heating electrode layer 601, then the current will also pass through the infrared emission layer 901, which will cause the resistance of the heating electrode layer 601 to change. Under the same external voltage, the temperature obtained by the MEMS light source will deviate significantly from the design value and cannot meet the working requirements. The above problems can be solved by setting an insulating isolation layer 701 between the two.

[0124] like Figure 9 As shown, in a more optimized solution of this embodiment, the infrared light source is further provided with a protective layer 1001, which covers the area on the upper surface of the MEMS infrared light source except for the heating electrode pad 801. The protective layer 1001 plays a role in protecting the internal structure. In this embodiment, according to the performance requirements of the device, the material of the protective layer 1001 is mainly made of materials with strong infrared radiation transmittance, high strength and hardness, and strong corrosion resistance and heat resistance. Specifically, the material of the protective layer 1001 selected in this embodiment includes any one or more combinations of silicon oxide, silicon nitride, aluminum oxide, and hafnium oxide.

[0125] Example 2

[0126] With respect to the MEMS infrared light source with a special structure and improved photoelectric conversion efficiency described in Example 1, this embodiment further provides a manufacturing method specifically for producing such a device. The manufacturing process designed in this embodiment, based on the core structural features of the device, employs the following steps: first, a pit 100 is etched, then pit 100 is filled with sacrificial layer 401 material, then various functional layers are generated on a plane, and finally, after the functional layers are completely machined, the sacrificial layer 401 within pit 100 is replaced by a sacrificial window 1002 that connects to pit 100 to complete the product manufacturing process. Specifically, to achieve the selective removal of sacrificial layer 401, this process places sacrificial window 1002 on the support layer 501 closest to pit 100 in substrate 101.

[0127] Option 1

[0128] like Figure 10 As shown, for a MEMS infrared light source comprising only a substrate 101, a support layer 501, a heating electrode layer 601, and an infrared emission layer 901, and containing a cavity of a special shape between the substrate 101 and the support layer 501, and a reflective layer 301 of a specific shape distributed in the cavity, the manufacturing method provided in this embodiment includes the following process steps:

[0129] (1) Mask processing of substrate:

[0130] A substrate 101 is provided, and a preset amount of mask 201 layer material is deposited on the surface of the substrate 101 to be processed to form the required mask 201 layer.

[0131] In particular, the substrate 101 of this embodiment can be made of any of a variety of existing materials. Silicon is the preferred material for the substrate 101, with the silicon (100) crystal plane being the surface to be processed. The mask 201 layer can be made of any of silicon oxide, silicon nitride, Cr, Au, Pt, and a NiCr alloy.

[0132] (2) Preparation of corrosion window:

[0133] According to the preset window size and shape, a portion of the mask layer 201 on the surface to be processed is removed using photolithography to form an etching window on the substrate 101. The etching window is specifically designed according to the shape of the upper opening of the designed MEMS infrared light source pit 100. The area exposed below the etching window is the area of the substrate 101 that needs to be etched.

[0134] (3) Anisotropic corrosion:

[0135] The substrate 101 is chemically etched by an anisotropic etching process to form a pit 100 in an etching window region of the substrate 101 that is recessed toward the inside of the substrate 101 and has a gradually decreasing diameter.

[0136] In this embodiment, any one of TMAH aqueous solution, KOH aqueous solution, NaOH aqueous solution, mixed aqueous solution of ethylenediamine and catechol, and NH4OH aqueous solution is used as the required anisotropic etching solution for the silicon substrate 101. During the etching process, it is necessary to control the etching process so that the etching depth is controlled to be 1-50 μm.

[0137] (4) Preparation of reflective layer:

[0138] A predetermined amount of reflective layer 301 material is deposited in the recess 100 on the surface of the substrate 101 using a physical vapor deposition process to form the desired reflective layer 301. The reflective layer 301 can be a single metal coating made of one of Ag, Au, Cu, and Al. Alternatively, the reflective layer 301 can be a composite metal coating made by sequentially depositing multiple materials such as Ag, Au, Cu, and Al. Alternatively, a dielectric film Bragg plating layer can be prepared as the desired reflective layer 301.

[0139] (5) One-time polishing:

[0140] The surface of substrate 101 to be processed is polished to remove the surface coating on the substrate 101 surface other than the pit 100, including the material of the etching mask 201 layer and the reflective layer 301 material. The polishing process adopts wet etching or chemical mechanical polishing. When wet etching is used, the etching mask 201 layer and other structures (reflective layer 301 and substrate 101) are selectively etched to remove the etching mask 201 layer and the reflective layer 301 material above it. In this way, the reflective layer 301 is retained in the pit 100, while the upper surface of the substrate 101 outside the pit 100 is exposed. When chemical mechanical polishing is used, the reflective layer 301 material and the etching mask 201 layer material in the area outside the pit 100 are polished away, exposing the upper surface of the substrate 101 outside the pit 100, while retaining the reflective layer 301 in the pit 100.

[0141] (6) Preparation of sacrificial layer:

[0142] The pit 100 in the substrate 101 is filled with a sacrificial layer 401 material that can be selectively removed by any means. The sacrificial layer 401 material is selected from SiO2, phosphosilicate glass, silica gel, polyimide, SU-8, polydimethylsiloxane (PDMS), gelatin, polyethylene glycol, parylene, and benzocyclobutene.

[0143] (7) Secondary polishing:

[0144] The surface of the substrate 101 to be processed filled with the sacrificial layer 401 material is subjected to a secondary polishing process to ensure that the sacrificial layer 401 material in the pit 100 is flush with the surrounding surface of the substrate 101. The polishing process adopts dry etching or chemical mechanical polishing.

[0145] (8) Preparation of support layer:

[0146] The required support layer 501 is formed on the surface of the substrate 101 on the side containing the sacrificial layer 401. The support layer 501 completely covers the underlying substrate 101 and the sacrificial layer 401. The support layer 501 is formed using a physical vapor deposition or chemical vapor deposition process; the generated support layer 501 is a single coating layer composed of silicon oxide or silicon nitride, or a multi-layer composite coating composed of silicon oxide or silicon nitride deposited layer by layer in a predetermined sequence.

[0147] (9) Preparation of heating electrode layer:

[0148] The required heating electrode layer 601 is formed on the surface of the support layer 501. The heating electrode layer 601 is located above the corresponding pit 100 in the substrate 101. The left and right sides of the heating electrode layer 601 completely cover the pit 100, while the front and back sides are located in the area inside the pit 100 and do not cover the pit 100. The heating electrode layer 601 is formed by physical vapor deposition or chemical vapor deposition; the material of the heating electrode layer 601 is selected from any one of Pt, Mo, NiCr alloy, polysilicon, SiC, Cu, W, HfB2, PtSi, and SnO2.

[0149] To improve the interfacial adhesion between the support layer 501 and the heating electrode layer 601, in a more optimized embodiment, a transition layer 5011 made of a specific material may be first deposited on the surface of the support layer 501, and then the desired heating electrode layer 601 is formed. The transition layer 5011 may be selected from any one of Ti, Cr, and Ni, depending on the materials used for the heating electrode layer 601 and the support layer 501.

[0150] (10) Preparation of heating electrode pads:

[0151] Two parallel long heating electrode pads 801 are prepared above the heating electrode layer 601 and do not exceed the distribution area of the heating electrode layer 601. The distribution areas of the two heating electrode pads 801 are separated from or circumscribed by the enclosed area of the upper opening of the pit 100.

[0152] The heating electrode pad 801 is electrically connected to the heating electrode layer 601 , and the material for preparing the heating electrode pad 801 is selected from any one of AlSi alloy, Au, Al, NiCr alloy, and NiV alloy.

[0153] (11) Preparation of infrared emission layer:

[0154] The infrared emitting layer 901 is formed on the heating electrode layer 601 inside the heating electrode pad 801. The infrared emitting layer 901 is located in the area where the four ends of the heating electrode pad 801 are connected.

[0155] The infrared emitting layer 901 is prepared from a material with high infrared emissivity. The thickness of the prepared infrared emitting layer 901 is 50-1000 nm. The high infrared emissivity material used includes a mixture of any one or more of NiCr alloy, TiN, TiAlN, amorphous carbon, SiC, NiCrO compound, ZrO2, HfO2, La1-xCaxCrO3 (0≤x≤0.5), and carbon nanotubes.

[0156] In particular, in other more optimized embodiments, the emitting surface of the processed infrared emitting layer 901 has a rough surface structure.

[0157] (12) Preparation of sacrificial window:

[0158] The support layer 501 material is etched by photolithography technology, and at least one penetrating sacrificial window is processed in a specific area without damaging the heating electrode layer 601 and the infrared emission layer 901 above, so as to expose the sacrificial layer 401 material in the pit 100 below. Figure 11 for Figure 5 The cross-sectional structural diagram of the MEMS infrared light source taken from two sides allows for a more intuitive view of the relative positional relationship between the sacrificial window, the support layer 501 and the recess 100 .

[0159] (13) Removal of sacrificial layer 401:

[0160] According to the specificity of the selected sacrificial material, a specific technical means is used to selectively remove all the sacrificial layer 401 materials filled in the pit 100 to form the required cavity structure; thereby preparing the required MEMS infrared light source.

[0161] A solvent or solution capable of directionally corroding the sacrificial layer 401 material is used as a selective etching liquid for immersion treatment. The etching liquid diffuses into the cavity through the sacrificial window and completely removes the sacrificial layer 401 material in the cavity. After the sacrificial layer 401 is removed, the product is cleaned and dried.

[0162] The final MEMS infrared light source includes four structural layers: substrate 101, support layer 501, heating electrode layer 601 and infrared emission layer 901; and contains a special-shaped cavity between the substrate 101 and the support layer 501, in which a specific-shaped reflective layer 301 is distributed.

[0163] Option 2

[0164] On the basis of the first solution, when the prepared infrared emission layer 901 is conductive, a step of preparing the isolation layer 701 is added between steps (9) and (10). After the isolation layer 701 is prepared, the step of preparing the heating electrode pad 801 in step (10) needs to first remove the isolation layer 701 in a part of the area used to set the heating electrode pad 801 by a photolithography stripping method, so that the heating electrode pad 801 is electrically connected to the heating electrode layer 601 below; and in step (11), the infrared emission layer 901 is located on the upper surface of the isolation layer 701.

[0165] Specifically, the isolation layer 701 is formed by physical vapor deposition or chemical vapor deposition, and the material is one of silicon oxide, silicon nitride, and aluminum oxide, or a combination of any multiple thereof.

[0166] The overall structure of the MEMS light source prepared at this time includes, from bottom to top, a substrate 101, a support layer 501, a heating electrode layer 601, an infrared emission layer 901, and a heating electrode pad 801. A cavity is provided at the interface between the substrate 101 and the support layer 501, and a complete reflective layer 301 is provided on the inner wall of the cavity near the substrate 101.

[0167] Option 3

[0168] On the basis of the second solution, in order to improve the corrosion resistance and other weather resistance of the product, a step of preparing a protective layer 1001 is added between step (11) and step (12). The prepared protective layer 1001 completely covers the upper surface of the infrared emission layer 901, the infrared electrode layer and the support layer 501. In addition, the sacrificial window opened in step (12) actually removes the protective layer 1001 and the support layer 501 at the same time, because the protective layer 1001 also covers the support layer 501 in the area where the sacrificial window is opened.

[0169] In this embodiment, the protective layer 1001 is formed by physical vapor deposition or chemical vapor deposition, and the material is selected from any one or more combinations of silicon oxide, silicon nitride, aluminum oxide, and hafnium oxide.

[0170] It should be noted that in the manufacturing method provided in this embodiment, the protective layer 1001 not only serves as the outer protective layer 1001 of the entire MEMS light source product produced. It also serves as the outer cladding covering the heating electrode layer 601, the isolation layer 701, and the infrared emission layer 901 when the substrate 101 is removed by a selective etchant in step (13). At this time, the selective solvent can only enter the pit 100 of the substrate 101 through the sacrificial window. When selecting the etchant, it is sufficient to select a solvent that can etch the sacrificial layer 401 but will not affect the materials of the support layer 501, the substrate 101, the reflective layer 301, and the protective layer 1001.

[0171] In order to more clearly demonstrate the manufacturing process provided in this embodiment, the following Figure 12-Figure 26 A set of continuous animated images are used to illustrate the complete manufacturing process of the complete product in Scheme 3, which includes a substrate 101, a supporting layer 501, a heating electrode layer 601, an isolation layer 701, an infrared emitting layer 901, a heating electrode pad 801, and a protective layer 1001. Figure 13-Figure 26 The diagram shows the morphological changes of the semi-finished products or products obtained after completing different manufacturing process steps.

[0172] 1. Mask processing of substrate

[0173] The mask 201 on the substrate 101 is formed roughly as follows Figure 12 As shown in the figure, it can be seen that the mask 201 is located on the upper layer of the substrate 101.

[0174] 2. Preparation of corrosion window

[0175] The etching window was successfully prepared, and the mask 201 contained a gap, roughly as shown Figure 13 shown.

[0176] 3. Anisotropic corrosion

[0177] After the anisotropic etching, the substrate 101 at the mask 201 is not affected, and the exposed substrate 101 is etched. Moreover, because the anisotropic etching is adopted, the etched pit 100 is as follows: Figure 14 The upper mouth is large and the lower mouth is small.

[0178] 4. Preparation of reflective layer

[0179] Because the reflective layer 301 is prepared by a sputtering or evaporation deposition process in this embodiment, Figure 15 The reflective layer 301 material is deposited on the upper surfaces of the middle substrate 101 and the mask 201 .

[0180] 5. One-time polishing

[0181] The goal of the first polishing is to remove the mask 201 material and the reflective layer 301 material on the surface of the substrate 101 except for the pit 100. Figure 16 status.

[0182] 6. Preparation of sacrificial layer

[0183] The sacrificial layer 401 is directly filled in the pit 100. In order to ensure that the sacrificial layer 401 is completely filled, the sacrificial layer 401 is usually allowed to "overflow" a little, such as Figure 17 shown.

[0184] 7. Secondary polishing

[0185] The goal of the secondary polishing is to remove the overflowed sacrificial layer 401 and expose the substrate 101 outside the pit 100 again; Figure 18 Therefore, a little more can be ground off during polishing to ensure that the sacrificial layer 401 material in the pit 100 remains flush with the surrounding substrate 101 surface.

[0186] 8. Preparation of support layer

[0187] Figure 19 As can be seen in the figure, a complete supporting layer 501 is grown on the sacrificial layer 401 and the substrate 101 .

[0188] 9. Preparation of heating electrode layer

[0189] Figure 20 It can be seen that a heating electrode layer 601 is formed above the support layer 501 and is shorter than the support layer 501. Furthermore, from the current viewing angle, the left and right sides of the electrode layer are longer than the recess 100. However, from the front and back viewing angles corresponding to the image, the heating electrode layer 601 is slightly shorter than the recess 100 to reserve a sacrificial window.

[0190] 10. Preparation of isolation layer

[0191] In this embodiment, a complete isolation layer 701 is provided above the heating electrode layer 601. Figure 21 As shown, the isolation layer 701 is as large as the heat-generating electrode layer 601 .

[0192] 11. Preparation of heating electrode pads

[0193] In this embodiment, a heating electrode pad 801 is prepared on the isolation layer 701. Figure 22 As can be seen in FIG, the isolation layer 701 at the heating electrode pad 801 is removed, so that the heating electrode pad 801 is directly electrically connected to the heating electrode layer 601 below. It should be noted that the heating electrode pad 801 is actually a long strip. Figure 22 Can't see from perspective.

[0194] 12. Preparation of infrared emission layer

[0195] from Figure 23 As can be seen from the figure, in this embodiment, an infrared emitting layer 901 is prepared on the isolation layer 701 between the two heating electrode pads 801.

[0196] 13. Preparation of protective layer

[0197] like Figure 24As shown, the infrared emission layer 901 is located at the top layer of the device, and because the sizes of the layers are inconsistent, it is in the shape of a "multi-layer cake" that shrinks step by step, so the protective layer 1001 will cover the infrared emission layer 901, the isolation layer 701, the heating electrode layer 601 and the support layer 501.

[0198] 14. Sacrificial Window Preparation

[0199] In this embodiment, the characteristic areas of the protective layer 1001 and the support layer 501 are penetrated to connect the pit 100 below and expose the sacrificial layer 401. Figure 12-Figure 24 The sacrifice window is not visible under the corresponding viewing angle. The specific diagram of the sacrifice window can be seen in Figure 25 Top view.

[0200] 15. Sacrificial layer removal

[0201] After the sacrificial window 1002 is formed, the sacrificial layer 401 material in the pit 100 can be completely removed by using a specific solvent to obtain the following: Figure 26 The final MEMS infrared light source product.

[0202] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for manufacturing a MEMS infrared light source, characterized in that: It is used to manufacture a MEMS infrared light source containing a cavity and a reflective layer between a substrate and a support layer; the manufacturing method comprises the following steps: (1) Mask processing of substrate: Providing a substrate, and depositing a preset amount of mask layer material on the surface to be processed of the substrate to form a required etching mask layer; (2) Preparation of corrosion window: According to the preset window size and shape, a portion of the mask layer on the surface to be processed is removed using photolithography technology to form an etching window on the substrate; the area exposed below the etching window is the substrate area to be etched; (3) Anisotropic corrosion: Chemically etching the substrate by an anisotropic etching process to form a pit in the etching window region of the substrate that is recessed toward the interior of the substrate and has a gradually decreasing diameter; (4) Preparation of reflective layer: Depositing a preset amount of reflective layer material in the pits on the surface of the substrate using a physical vapor deposition process to form a desired reflective layer; (5) One-time polishing: Polishing the surface of the substrate to be processed to remove the surface coating on the substrate surface other than the pits, including the etching mask layer material and the reflective layer material; (6) Preparation of sacrificial layer: Filling the pits in the substrate with a sacrificial layer material that can be selectively removed by any means; (7) Secondary polishing: Performing a secondary polishing process on the to-be-processed surface of the substrate filled with the sacrificial layer material, so that the sacrificial layer material in the pit remains flush with the surrounding substrate surface; (8) Preparation of support layer: Generating a required supporting layer on the surface of the substrate containing the sacrificial layer, wherein the supporting layer completely covers the substrate and the sacrificial layer below; (9) Preparation of heating electrode layer: The required heating electrode layer is prepared on the surface of the support layer, and the heating electrode layer is located above the corresponding pit in the substrate; the left and right sides of the heating electrode layer completely cover the pit, and the front and back sides are located in the area inside the pit and do not cover the pit; (10) Preparation of heating electrode pads: Two parallel long strip heating electrode pads are prepared above the heating electrode layer and do not exceed the distribution area of the heating electrode layer; wherein the distribution areas of the two heating electrode pads are separated from or circumscribed to the enclosed area of the upper opening of the pit; (11) Preparation of infrared emission layer: A required infrared emission layer is prepared above the heating electrode layer on the inner side of the heating electrode pad; the infrared emission layer is located in the area where the four end points of the heating electrode pad are connected; (12) Preparation of sacrificial window: The supporting layer material is etched by photolithography technology, and at least one penetrating sacrificial window is processed in a corresponding area without damaging the heating electrode layer and the infrared emission layer above, so as to expose the sacrificial layer material in the pit below; The opening area of the sacrificial window is located above the sacrificial layer and is tangent to or separated from the distribution position of the heating electrode layer; (13) Removal of sacrificial layer: According to the specificity of the selected sacrificial material, a solvent or solution capable of directionally corroding the sacrificial layer material is used to selectively remove all the sacrificial layer materials filled in the pit to form the required cavity structure; thereby preparing the required MEMS infrared light source.

2. The method for manufacturing a MEMS infrared light source according to claim 1, wherein: In step (1), silicon is selected as the substrate material, and the silicon (100) crystal plane is used as the surface to be processed; the material of the mask layer is selected from any one of silicon oxide, silicon nitride, Cr, Au, Pt and NiCr alloy; In step (3), any one of TMAH aqueous solution, KOH aqueous solution, NaOH aqueous solution, mixed aqueous solution of ethylenediamine and catechol, and NH4OH aqueous solution is used as the anisotropic etching solution; the etching depth is controlled to be 1-50 μm.

3. The method for manufacturing a MEMS infrared light source according to claim 1, wherein: In step (4), the reflective layer is a single metal coating made of one material among Ag, Au, Cu, and Al, or a composite metal coating is made by depositing multiple materials layer by layer; or a dielectric film Bragg coating is prepared as the required reflective layer.

4. The method for manufacturing a MEMS infrared light source according to claim 1, wherein: In step (6), the sacrificial layer material is selected from one of SiO2, phosphosilicate glass, silica gel, polyimide, SU-8, polydimethylsiloxane, gelatin, polyethylene glycol, polyparaxylene, and benzocyclobutene; In step (13), a solvent or solution capable of directionally corroding the sacrificial layer material is used as a selective etching liquid for immersion treatment, and the etching liquid diffuses into the cavity through the sacrificial window to completely remove the sacrificial layer material in the cavity; After the sacrificial layer is removed, the product is cleaned and dried.

5. The method for manufacturing a MEMS infrared light source according to claim 1, wherein: In step (5), the polishing process is performed by wet etching or chemical mechanical polishing; in step (7), the polishing process is performed by dry etching or chemical mechanical polishing.

6. The method for manufacturing a MEMS infrared light source according to claim 1, wherein: In step (8), the support layer is formed by physical vapor deposition or chemical vapor deposition; the generated support layer is a single coating composed of silicon oxide or silicon nitride, or a multi-layer composite coating composed of silicon oxide or silicon nitride deposited layer by layer in a preset order.

7. The method for manufacturing a MEMS infrared light source according to claim 1, wherein: In step (9), the heating electrode layer is formed by physical vapor deposition or chemical vapor deposition; the material of the heating electrode layer is selected from any one of Pt, Mo, NiCr alloy, polysilicon, SiC, Cu, W, HfB2, PtSi and SnO2; and / or First, a transition layer made of a specific material is deposited on the surface of the support layer; then the required heating electrode layer is generated; the transition layer is selected from any one of Ti, Cr, and Ni according to the different materials used for the heating electrode layer and the support layer.

8. The method for manufacturing a MEMS infrared light source according to claim 1, wherein: In step (10), the heating electrode pad is electrically connected to the heating electrode layer, and the material for preparing the heating electrode pad is selected from any one of AlSi alloy, Au, Al, NiCr alloy, and NiV alloy; In step (11), the required infrared emission layer is prepared by using a material with high infrared emissivity; the thickness of the prepared infrared emission layer is 50-1000nm; wherein the material with high infrared emissivity includes NiCr alloy, TiN, TiAlN, amorphous carbon, SiC, NiCrO compound, ZrO2, HfO2, La 1-x Ca x A mixture of any one or more of CrO3, 0≤x≤0.5 and carbon nanotubes; and / or The processed emission surface of the infrared emission layer has a rough surface structure.

9. The method for manufacturing a MEMS infrared light source according to claim 1, wherein: When the prepared infrared emission layer is conductive, a step of preparing an isolation layer is added between steps (9) and (10); and after preparing the isolation layer, the step of preparing the heating electrode pad in step (10) needs to first remove the isolation layer in a part of the area used to set the heating electrode pad by a photolithography stripping method, so that the heating electrode pad is electrically connected to the heating electrode layer below; and in step (11), the infrared emission layer is located on the upper surface of the isolation layer; The isolation layer is formed by physical vapor deposition or chemical vapor deposition, and the material is one of silicon oxide, silicon nitride, and aluminum oxide, or a combination of any multiple thereof.

10. The method for manufacturing a MEMS infrared light source according to claim 1, wherein: Between step (11) and step (12), a step of preparing a protective layer is added, and the prepared protective layer completely covers the upper surfaces of the infrared emitting layer, the infrared electrode layer and the support layer; The protective layer is formed by physical vapor deposition or chemical vapor deposition, and the material is selected from any one or more combinations of silicon oxide, silicon nitride, aluminum oxide, and hafnium oxide.

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