MEMS device and manufacturing method thereof

Abstract

The invention provides an MEMS device and a manufacturing method thereof, and the method comprises the following steps: providing a substrate which comprises a mirror surface region and a comb tooth region located at the outer side of the mirror surface region; etching the substrate to form a plurality of grooves arranged at intervals in the mirror surface area and the comb tooth area; forming a first mask layer to cover the side wall of the groove and the surface of the substrate and seal the opening of the groove; etching the first mask layer to expose part of the surface of the substrate and cover each region for forming the first comb teeth and each mirror surface region of the substrate; forming an epitaxial layer on the surface of the substrate and the first mask layer; forming a mirror surface structure on the epitaxial layer; the epitaxial layer is etched to form a supporting structure used for supporting the mirror surface structure and a plurality of second comb teeth located on the outer side of the mirror surface structure; the first mask layer serves as a mask, the substrate is etched to form a plurality of first comb teeth, and the first comb teeth and the second comb teeth are arranged in a staggered mode; and at least removing the first mask layer below the second comb teeth and the support structure.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a MEMS device and a method for manufacturing the same. Background Art

[0002] Some micro-electro-mechanical system (MEMS) devices, such as MEM mirror driver devices (such as MEMS galvanometers), usually require the preparation of upper and lower comb teeth that are staggered up and down. MEM mirror driver devices can deflect, modulate, open and close, and phase-control the light beam under the driving action. MEM mirror driver devices have the characteristics of light weight, small size, easy mass production, low production cost, excellent optical, mechanical properties and power consumption, and are therefore widely used in projection, display, optical communication, lidar and other scenarios.

[0003] In the related technology, two SOI wafers are usually used to prepare devices, which is costly, and the stress control of the thin film structure is complicated, the process is complicated, the bonding process is used multiple times, the bonding voids affect the yield, and the probability of abnormalities in the process is increased. Large cavities are often introduced, and there are many weak structures.

[0004] Therefore, it is necessary to propose a new MEMS device and a manufacturing method thereof to at least partially solve the above problems. Summary of the invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0006] In view of the existing problems, the present application provides a method for manufacturing a MEMS device, comprising the following steps:

[0007] Providing a substrate, the substrate comprising a mirror region and a comb-tooth region located outside the mirror region;

[0008] Etching the substrate to form a plurality of grooves spaced apart in the mirror region and the comb-teeth region;

[0009] forming a first mask layer to cover the sidewalls of the trench, the surface of the substrate and seal the opening of the trench;

[0010] Etching the first mask layer to expose a portion of the surface of the substrate and cover each region of the substrate for forming the first comb teeth and the mirror region;

[0011] forming an epitaxial layer on the surface of the substrate and the first mask layer;

[0012] forming a mirror structure on the epitaxial layer, wherein the mirror structure corresponds to the mirror area;

[0013] Etching the epitaxial layer to form a support structure for supporting the mirror structure and a plurality of second comb teeth located outside the mirror structure, wherein each second comb tooth corresponds to a groove in the comb tooth region, and the plurality of second comb teeth are located outside the support structure;

[0014] Using the first mask layer as a mask, etching the substrate to form a plurality of first comb teeth, wherein the plurality of first comb teeth and the plurality of second comb teeth are arranged alternately;

[0015] At least the first mask layer located under the second comb teeth and under the support structure is removed.

[0016] In one example, a filling cavity is further formed in the first mask layer located in the trench, wherein a top of the filling cavity is located below the surface of the substrate.

[0017] In one example, forming a first mask layer to cover the sidewalls of the trench, the surface of the substrate and seal the opening of the trench includes:

[0018] forming a first mask material layer on the sidewalls of the trench and the surface of the substrate, wherein the thickness of the first mask material layer on the top sidewall of the trench is greater than that of the first mask material layer on the bottom sidewall of the trench;

[0019] Etching and removing a portion of the first mask material layer so that the minimum opening of the trench is located below the surface of the substrate;

[0020] forming a second mask material layer on the first mask material layer, and the second mask material layer seals the opening of the trench;

[0021] A third mask material layer is formed on the second mask material layer, and planarization is performed to form a first mask layer, wherein the third mask material layer has a higher density than the second mask material layer.

[0022] In one example, before etching the epitaxial layer to form a plurality of second comb teeth located outside the mirror structure, after forming the epitaxial layer, the manufacturing method further includes:

[0023] The side of the substrate facing away from the epitaxial layer is thinned.

[0024] In one example, after forming the first comb teeth and the second comb teeth and before removing the first mask layer, the manufacturing method further includes:

[0025] Wet cleaning is performed to remove etching residues formed when etching the epitaxial layer and the substrate, wherein during the cleaning process, the first mask layer supports the second comb teeth, and the first mask layer in the mirror area supports the support structure.

[0026] In one example, a method for forming a substrate includes: providing a base, forming an insulating layer on a surface of the base, and epitaxially growing a device layer on the insulating layer, wherein the device layer is used to form first comb teeth.

[0027] In one example, before forming the trench, the manufacturing method further includes:

[0028] forming at least two isolation trenches spaced apart from each other in the device layer;

[0029] Etching the substrate to form a plurality of grooves spaced apart in the mirror region and the comb-teeth region, comprising:

[0030] The device layer is etched to form a plurality of grooves spaced apart in the mirror region and the comb-teeth region, and the isolation groove is etched at the same time so that the bottom of the isolation groove extends to the insulating layer.

[0031] In one example, the thickness of the first mask layer on the surface of the substrate is less than 1.5 μm; and / or

[0032] The aspect ratio of the trench is greater than or equal to 3 and less than or equal to 60.

[0033] The present application also provides a MEMS device, the MEMS device comprising:

[0034] A substrate, the substrate comprising a mirror region and a comb-tooth region located outside the mirror region;

[0035] A plurality of first comb teeth are arranged at intervals in the comb tooth area;

[0036] A plurality of grooves are arranged at intervals in the mirror surface area;

[0037] An epitaxial layer is arranged on the substrate, the epitaxial layer comprises a plurality of second comb teeth arranged at intervals and a support structure, the plurality of second comb teeth are located outside the support structure, and the plurality of second comb teeth and the plurality of first comb teeth are arranged alternately;

[0038] The mirror structure is arranged on the supporting structure, and the mirror structure and the mirror area are opposite to each other.

[0039] In one example, the substrate includes a base layer, a device layer, and an insulating layer arranged between the base layer and the device layer, at least two isolation grooves arranged at intervals are formed in the substrate, and a plurality of first comb teeth are arranged between adjacent isolation grooves, wherein the isolation grooves penetrate the device layer and extend into the insulating layer.

[0040] According to the MEMS device and its manufacturing method provided by the present application, an epitaxial layer is formed on the surface of the substrate and the first mask layer, and the epitaxial layer is used to prepare the second comb teeth. Compared with the related technology of using the traditional SOI wafer, the present application reduces the use of SOI wafers, so its cost is lower, the difficulty of stress regulation is reduced and the adjustment cycle is shortened. The position of each second comb tooth of the present application corresponds to a groove, and the groove is filled with the first mask layer. Then, after the first comb teeth and the second comb teeth are formed, the first mask under the second comb teeth can be used to support them, and the first hard mask layer under the support structure also supports them, thereby improving the stability of the structure, so that the subsequent process is more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The following drawings of the present application are used as a part of the present application for understanding the present application. The drawings show the embodiments of the present application and their descriptions, which are used to explain the principle of the present application.

[0042] In the attached figure:

[0043] Figures 1A to 1J A cross-sectional schematic diagram of a device obtained by sequentially implementing a manufacturing method of a MEMS device in a related art is shown;

[0044] Figure 2 A schematic flow chart showing a method for manufacturing a MEMS device in one embodiment of the present application is shown;

[0045] FIG. 3A to FIG. 3K A schematic cross-sectional view of a device obtained by sequentially implementing a method for manufacturing a MEMS device according to an embodiment of the present application is shown;

[0046] FIG. 4A to FIG. 4E A partial cross-sectional schematic diagram of a device obtained by sequentially implementing a method for manufacturing a first mask layer according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0047] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features well known in the art are not described.

[0048] It should be understood that the present application can be implemented in different forms and should not be construed as being limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present application to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

[0049] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as a second element, component, region, layer or part.

[0050] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like, may be used herein for convenience of description to describe the relationship of one element or feature shown in the figures to other elements or features. It should be understood that the spatially relative terms are intended to include different orientations of the galvanometer in use and operation in addition to the orientations shown in the figures. For example, if the galvanometer in the accompanying drawings is flipped, then the elements or features described as "under the other elements" or "under it" or "under it" will be oriented as "over" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. The galvanometer may be otherwise oriented (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0051] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "a", "an" and " / the" are also intended to include plural forms, unless the context clearly indicates another way. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0052] like Figures 1A to 1J As shown, in the related art, MEMS optoelectronic devices are prepared by the following method. First, Figure 1A As shown, a SOI wafer 100 is provided for forming a bottom comb structure;

[0053] Then, if Figure 1B As shown, a marking pattern 110 is formed in the SOI wafer 100 by photolithography and etching processes, and then an oxide mask layer 120 is deposited to cover the surface of the SOI wafer 100 and fill the marking pattern 110, and then the oxide mask layer 120 is etched to form a comb mask layer that defines the size and position of the first comb teeth;

[0054] Then, if Figure 1C As shown, a photoresist mask layer 140 is formed to cover the comb-tooth mask layer and the surface of the SOI wafer 100, and the photoresist mask layer 140 is photolithographically processed to define the position and size of the isolation groove to be formed, that is, an opening is formed in the photoresist mask layer 140, and the opening exposes the area of ​​the SOI wafer 100 where the isolation groove is to be etched to form the isolation groove, and the SOI wafer 100 is etched to form the isolation groove 130.

[0055] Then, if Figure 1D As shown, the photoresist mask layer is removed, and the SOI wafer 100 is etched using the comb-tooth mask layer as a mask to form a plurality of bottom comb-tooth structures 150 , and the isolation trench 130 is further etched to be connected to the buried oxide layer of the SOI wafer 100 .

[0056] Then, if Figure 1E and Figure 1F As shown, the cap wafer 201 is etched to form a groove opposite to the bottom comb teeth, and a support layer is located in the groove, and the support layer covers the area of ​​the cap wafer 201 for forming the top comb teeth, and the side of the cap wafer 201 formed with the support layer is bonded to the side of the SOI wafer 100 formed with the bottom comb tooth structure 150, and the cap wafer 201 is also a SOI wafer.

[0057] Then, if Figure 1FAs shown, the side of the cap wafer 201 away from the bottom comb structure 150 is trimmed, mechanically ground and fully etched to expose the buried oxide layer of the cap wafer 201 , and the buried oxide layer is removed to expose the bottom silicon of the cap wafer 201 .

[0058] Then, if Figure 1G As shown, a hard mask layer 202 such as a silicon oxide hard mask layer is deposited on the cap wafer 201, and then the hard mask layer 202 is etched to define the position and size of the predetermined top comb structure and expose the bottom silicon of the cap wafer 201 for setting the mirror structure. An aluminum pad is formed on the bottom silicon.

[0059] Then, if Figure 1H and Fig. 1I As shown, a mirror structure 203 (for example, a mirror pattern formed of a metal material) is formed on the cap wafer 201, and the top comb tooth structure and the bottom comb tooth structure are located on the outside of the mirror structure, and the back side of the SOI wafer 100 away from the bottom comb tooth structure 150 is ground (i.e., back side thinning) to thin the SOI wafer 100. However, since the size of the mirror structure is relatively large, about 1000 μm, and the area of ​​the SOI wafer corresponding to the mirror structure is a large cavity structure, it is easy to cause the supporting structure (for example, a silicon membrane structure) used to support the mirror structure to break during back side thinning, resulting in a silicon explosion problem.

[0060] Finally, continue as Fig. 1I As shown, the cap wafer 201 is etched by deep reactive ion etching (DRIE) using the hard mask layer as a mask to form a plurality of top comb structures 204 and a support structure 205 for supporting the mirror structure 203 .

[0061] Afterwards, if Figure 1J As shown, the support layer and the hard mask layer etc. are released so that the top comb structure 204 is movable.

[0062] The above-mentioned related technologies have the following disadvantages:

[0063] 1. Using two SOI wafers has high cost and complicated process;

[0064] 2. The Si film layer obtained by SOI wafer needs to adjust the stress of the top silicon of SOI wafer, which is complicated to adjust. The thinning process in the preparation process of SOI wafer is easy to introduce grinding damage layer;

[0065] 3. The bonding of two SOI wafers is achieved through the bonding process, but bonding voids are likely to exist at the bonding interface, which affects the yield and may increase the probability of abnormalities in the process;

[0066] 4. When thinning the back side, it is easy to cause the support structure (such as silicon film structure) used to support the mirror structure to break, resulting in silicon explosion problems.

[0067] 5. After the structural layer is released, the residual polymer and photoresist residues on the sidewalls of the comb teeth can only rely on dry cleaning process, and wet cleaning cannot be performed. Therefore, it is not easy to effectively clean these residues.

[0068] In order to solve the problems existing in the related art, the present application proposes a method for manufacturing a MEMS device. Figure 2 , FIG. 3A to FIG. 3K and FIG. 4A to FIG. 4E A method for manufacturing a MEMS device according to the present application is described, wherein: Figure 2 A schematic flow chart showing a method for manufacturing a MEMS device in one embodiment of the present application is shown; FIG. 3A to FIG. 3K A schematic cross-sectional view of a device obtained by sequentially implementing a method for manufacturing a MEMS device according to an embodiment of the present application is shown; FIG. 4A to FIG. 4E A partial cross-sectional schematic diagram of a device obtained by sequentially implementing a method for manufacturing a first mask layer according to an embodiment of the present application is shown.

[0069] In one embodiment, Figure 2 As shown, the manufacturing method 200 of the MEMS device provided in the present application includes the following steps S210 to S290:

[0070] First, in step S210, Figure 3A As shown, a substrate 500 is provided, wherein the substrate 500 includes a mirror region and a comb-teeth region located outside the mirror region.

[0071] In one example, the substrate 500 may include at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP, InGaAs, or other III / V compound semiconductors. Although several examples of materials that can form the substrate 500 are described herein, any material that can be used as the substrate 500 falls within the spirit and scope of the present application.

[0072] Without considering the cost, the substrate 500 may also be an SOI substrate or other suitable substrates.

[0073] In some embodiments, in order to reduce costs, the following method can be used to form the substrate 500. For example, first, a base 501 is provided, an insulating layer 502 is formed on the surface of the base 501, and a device layer 503 is epitaxially grown on the insulating layer 502. For example, an oxide layer can be grown as the insulating layer 502 by a thermal oxidation method, that is, a buried oxide layer. A device layer 503 such as a silicon layer can be formed on the insulating layer 502 by an epitaxial growth method, wherein the thickness of the device layer 503 can range from 10 μm to 30 μm, or other suitable thicknesses. The device layer 503 is used for the subsequent production of the first comb teeth and a plurality of grooves located in the mirror area.

[0074] The mirror area of ​​the substrate 500 corresponds to the mirror structure formed subsequently, and the comb-tooth area is used to form the first comb teeth.

[0075] In some examples, such as Figure 3B As shown, a marking pattern can also be formed in the substrate by photolithography and etching processes. The marking pattern is an inner groove and is located in the edge area of ​​the substrate 500 and outside the comb-tooth area.

[0076] Next, in step S220, FIG. 3B to FIG. 3D As shown, the substrate 500 is etched to form a plurality of grooves arranged at intervals in the mirror region and the comb-teeth region.

[0077] The grooves 510 may be formed in the substrate 500 by any suitable method. In one embodiment, a hard mask layer 505 may be first formed on the surface of the substrate 500, and then the hard mask layer 505 may be patterned to expose the area where the grooves 510 are to be formed, and then the substrate 500 may be etched by, for example, dry etching or wet etching to form a plurality of grooves 510, wherein the number of the grooves 510 may be reasonably determined according to actual needs, and the material of the hard mask layer 505 may be any material suitable as a hard mask in the art, including but not limited to SiO2, SiCN, SiN, SiC or SiON. The hard mask layer 505 may be formed by any suitable deposition method, for example, chemical vapor deposition, physical vapor deposition or atomic layer deposition. Preferably, dry etching is used for etching. Specifically, the device layer 503 of the substrate may be etched to form a plurality of grooves 510 spaced apart in the mirror area and the comb area. Optionally, the thickness of the hard mask layer 505 may be in the range of 1000-5500 angstroms, for example, 2000 angstroms, 3000 angstroms, or 5000 angstroms.

[0078] Optionally, the aspect ratio of the groove 510 may be greater than or equal to 3 and less than or equal to 60, which may be reasonably set according to actual needs. By making the groove 510 have a higher aspect ratio, it may be beneficial to form a filling cavity in the groove 510 when the first mask layer 520 is subsequently formed. Optionally, the depth of the groove 510 may range from 5 μm to 60 μm, and the width of the groove 510 may range from 1 μm to 5 μm, or, further, the width may be 2 μm to 3 μm. It may be reasonably set according to actual needs.

[0079] The groove 510 formed in the comb-tooth region is used to be opposite to the second comb-tooth 560 to be formed subsequently, while the groove 510 formed in the mirror region is intended to be opposite to the mirror structure 509 to be formed subsequently.

[0080] In some embodiments, before etching to form the grooves, Figure 3C and Figure 3D As shown, at least two isolation grooves 507 spaced apart are first formed in the substrate 500, for example, a photoresist layer 506 is formed to cover the patterned hard mask layer 505, and then the photoresist layer 506 is patterned by a photolithography process to expose a region in the substrate where the isolation grooves 507 are to be etched, and then the substrate is etched using the photoresist layer 506 as a mask to form the isolation grooves 507, and the isolation grooves 507 are arranged in the device layer 503 and spaced apart from the insulating layer 502, and then the photoresist layer 506 is removed, and then, as shown in FIG. Figure 3D As shown, while etching to form the aforementioned trench 510, the isolation trench 507 is also etched so that the bottom of the isolation trench 507 extends to the insulating layer 502. Optionally, the depth of the trench may be less than the depth of the isolation trench. Optionally, the hard mask layer may also be removed after the trench is formed.

[0081] Next, in step S230, Figure 3E and FIG. 4A to FIG. 4E As shown, a first mask layer 520 is formed to cover the sidewalls of the trench 510 , the surface of the substrate 500 , and seal the opening of the trench 510 .

[0082] It is worth mentioning that, for the convenience of presentation, FIG. 4A to FIG. 4E Only the local structure of the device is shown, for example Figure 3E A local schematic diagram of the area in the dashed box.

[0083] Exemplarily, the first mask layer 520 may fill the trench 510 completely, or, in other examples, a filling hole 511 is formed in the first mask layer 520 in the trench 510, wherein the top of the filling hole 511 is located below the surface of the substrate 500. By forming the filling hole 511 in the trench 510, the filling amount of the first mask layer 520 in the trench 510 can be reduced, so that the first mask layer 520 can be quickly removed in a short time. The top of the filling hole 511 is located below the surface of the substrate 500, which can ensure that the sealing of the opening of the trench 510 can be maintained during the subsequent process.

[0084] Optionally, the material of the first mask layer 520 may be silicon oxide, silicon nitride, silicon oxynitride or any other suitable insulating material, and may be composed of multiple material layers or a single film layer, which may be reasonably selected according to process requirements.

[0085] In a specific embodiment, the first mask layer 520 may be formed by the following method, including the following steps S231 to S234:

[0086] In step S231, Figure 4A As shown, a first mask material layer 521 is formed on the sidewalls of the groove 510 and the surface of the substrate 500, wherein the thickness of the first mask material layer 520 located on the top sidewall of the groove 510 is greater than the first mask material layer 521 located on the bottom sidewall of the groove, that is, the first mask material layer 521 located at the opening of the groove 510 protrudes further toward the center of the groove 510 than the first mask material layer 521 located on the bottom sidewall of the groove, thereby reducing the size of the opening of the groove 510 to facilitate subsequent sealing.

[0087] The material of the first mask material layer 521 may include silicon oxide, silicon nitride, silicon oxynitride or other suitable materials, wherein preferably, the material of the first mask material layer 521 includes plasma enhanced oxide (PEOX), that is, silicon oxide formed by a silicon dioxide precursor (such as a silicon source such as silane, and oxygen such as molecular oxygen and ozone) using a plasma enhanced chemical vapor deposition (PECVD) process. Due to the inherent characteristics of the plasma enhanced oxide, when the trench 510 is filled, the thickness of the first mask layer 520 located on the top sidewall of the trench 510 is greater than that of the first mask material layer 521 located on the bottom sidewall of the trench, so that the trench 510 can be partially sealed first, so that the opening of the trench 510 is significantly reduced.

[0088] In step S232, if Figure 4BAs shown, a portion of the first mask material layer 521 is etched away so that the minimum opening of the groove 510 is located below the surface of the substrate 500, thereby ensuring that the sealing of the opening of the groove 510 can be maintained during subsequent processes; optionally, the first mask material layer 521 can be etched by any suitable etching method, for example, a portion of the first mask material layer 521 is etched away by a blanket etching process, and the etching can be isotropic etching. Optionally, a blanket etching process can be performed by plasma etching, for example, the first mask material layer 521 is bombarded with plasma to achieve the purpose of removing a portion of the first mask material layer 521, and the plasma can be formed by ionizing a rare gas such as argon or helium. Optionally, a comprehensive etching process can be used to form a basically truncated cone-shaped inner groove that is narrow at the bottom and wide at the top above the opening of the groove 510, and the bottom of the inner groove is also the minimum opening of the groove 510, which is located below the surface of the substrate 500. In this way, it is convenient to seal the opening of the groove 510 later.

[0089] In step S233, if Figure 4C As shown, a second mask material layer 522 is formed on the first mask material layer 521 , and the second mask material layer 522 seals the opening of the trench 510 .

[0090] The second mask material layer 522 may be deposited by any suitable deposition method, such as physical vapor deposition, chemical vapor deposition or atomic layer deposition, etc. In one example, in order to further seal the opening of the trench 510, the material of the second mask material layer 522 includes an oxide formed by sub-atmospheric pressure chemical vapor deposition (SACVD) using an oxygen source and tetraethyl orthosilicate (TEOS) as raw materials, that is, SACVD TEOS oxide. Usually, the density of the oxide is relatively low, so the second mask material layer 522 can be formed on the first mask material layer 521 in the trench 510 by the SACVD TEOS oxide, and the trench 510 can also be better sealed.

[0091] The trench 510 is only partially filled by the first mask material layer 521 and the second mask material layer 522, so that the trench 510 can form a filling cavity 511. Optionally, the filling cavity 511 is located below the surface of the substrate 500, for example, at least 0.5 μm below the surface of the substrate 500.

[0092] Optionally, the thickness of the first mask layer 520 on the surface of the substrate 500 is less than 1.5 μm, or may be any other suitable thickness, and the first mask layer 520 on the surface of the substrate 500 is used as a mask for subsequently etching the substrate 500 to form first comb teeth.

[0093] In step S234, if Figure 4D and Figure 4E As shown, a third mask material layer 523 is formed on the second mask material layer 522 , and planarization is performed to form the first mask layer 520 , wherein the third mask material layer 523 has a higher density than the second mask material layer 522 .

[0094] The second mask material layer 522 can be formed by depositing by any suitable deposition method, such as physical vapor deposition, chemical vapor deposition or atomic layer deposition. In one example, the material of the third mask material layer 523 includes PE TEOS oxide, that is, TEOS oxide deposited by PECVD. For example, TEOS and O2 can be used as raw material gases to deposit a PETEOS oxide layer by PECVD, and its component is usually SiO2.

[0095] Optionally, the third mask material layer 523 has a higher density than the second mask material layer 522. By using a material with higher density for the third mask material layer 523, the density of the first mask layer 520 can be improved, and the sealing of the trench 510 can be made more secure.

[0096] like Figure 4E As shown, in order to obtain the first mask layer 520 with a flat surface, the third mask material layer 523 can be flattened, for example, a portion of the third mask material layer 523 can be removed by etching or chemical mechanical polishing. Since the bottom of the third mask material layer 523 at the groove 510 is lower than the top surface of the second mask material layer 522, the flattening can be stopped at the third mask material layer 523, and the third mask material layer 523 is retained at the groove 510. Finally, the first mask material layer 521, the second mask material layer 522 and the third mask material layer 523 constitute the first mask layer 520. The first mask layer can have a flatter surface through the flattening process, so as to facilitate the subsequent deposition of the epitaxial layer.

[0097] It is worth mentioning that for grooves 510 of different sizes, the first mask layer 520 can be formed through different process steps. For example, for a groove 510 of a larger size, a blanket etching process can be performed after the second mask material layer 522 is formed for the first time, and then the second mask material layer 522 can be formed for the second time. That is, the blanket etching process and the second mask material layer 522 can be repeated at least once to better seal the groove 510.

[0098] Next, in step S240, Figure 3FAs shown, the first mask layer 520 is etched to expose a portion of the surface of the substrate and cover each region of the substrate for forming the first comb teeth and the mirror region.

[0099] The first mask layer 520 can be etched by any suitable method to pattern the first mask layer 520. For example, a photoresist layer can be formed on the first mask layer 520, and then the photoresist layer is patterned by a photolithography process to define the position and size of the predetermined first comb teeth 550, and then the first mask layer 520 is etched using the patterned photoresist layer as a mask to achieve the patterning of the first mask layer 520, and then the photoresist layer is removed. In addition to defining the position of the first comb teeth 550, the first mask layer 520 also defines the position and size of the channel between adjacent first comb teeth 550 (that is, the first mask layer exposes the area of ​​the substrate used to form the channel between adjacent first comb teeth 550, so as to be etched later). In addition, the first mask layer 520 still keeps the opening of the capping groove 510 at the position of the groove 510. The first mask layer keeps covering the mirror area to avoid etching of the area when the first comb teeth are formed later.

[0100] Part of the substrate 500 outside the groove 510 can be used to make the first comb teeth 550. Specifically, the number of grooves 510 can be reasonably set according to the number of first comb teeth 550 to be made and the number of second comb teeth 560 to be made subsequently.

[0101] It should be noted that, for the convenience of illustration, Figure 3E Afterwards, the first mask layer 520 is shown with the same filling pattern, but this is intended to limit the number of layers of the first mask layer 520 , and the filling cavity 511 is also shown with a blank rectangle, but this is not intended to limit the shape of the filling cavity 511 .

[0102] It should also be noted that FIG. 3F to FIG. 3H ,as well as Figure 3J and Figure 3K Figure (b) is a local enlarged schematic diagram corresponding to the area within the rectangular dotted box in Figure (a).

[0103] Next, in step S250, Figure 3G As shown, an epitaxial layer 530 is formed on the surface of the substrate 500 and the first mask layer 520 .

[0104] The material of the epitaxial layer 530 is a semiconductor material, which can be Si, SiB, SiGe, SiC, SiP, SiGeB, SiCP, AsGa or other III-V binary or ternary compounds. In this embodiment, the material of the epitaxial layer 530 is Si.

[0105] The epitaxial layer 530 may be formed using one of low pressure chemical vapor deposition (LPCVD), plasma enhanced chemical vapor deposition (PECVD), ultra high vacuum chemical vapor deposition (UHVCVD), rapid thermal chemical vapor deposition (RTCVD), and molecular beam epitaxy (MBE).

[0106] Optionally, the epitaxial layer 530 can be used to subsequently fabricate the second comb teeth 560, ie, the top comb tooth structure, and its thickness can depend on the size of the second comb teeth to be fabricated, which is not specifically limited here. Exemplarily, the thickness of the epitaxial layer 530 can range from 20 μm to 30 μm.

[0107] By forming an epitaxial layer 530 on the surface of the substrate 500 and the first mask layer 520, and using the epitaxial layer 530 to prepare the second comb teeth 560, compared with the related technology of using the traditional SOI wafer, the present application reduces the use of SOI wafers, so its cost is lower, and the stress of the thin film layer structure can be regulated during the formation of the epitaxial layer 530, the regulation method is simpler, the difficulty of stress regulation is reduced, and the adjustment cycle is shortened. In addition, the method of forming the epitaxial layer by deposition can avoid the use of a bonding process, thereby avoiding the influence of the voids at the bonding interface on the device yield, and improving the product yield.

[0108] In some embodiments, the method of the present application also includes: a step of forming a pad 508 on the surface of the epitaxial layer 530. Specifically, a metal layer can be first deposited on the surface of the epitaxial layer 530, and then the metal layer is etched using a photolithography and etching process to form a pad 508, such as an aluminum pad.

[0109] Optionally, the aforementioned device layer 503 and epitaxial layer 530 may both be formed by a thick epitaxial (EPI) growth process, and their thicknesses may both be 20 μm-30 μm, thereby reducing the use of SOI wafers, lowering costs, and simplifying the process.

[0110] Next, in step S260, Figure 3H and Fig. 3I As shown, a mirror structure 509 is formed on the epitaxial layer, and the mirror structure 509 corresponds to the mirror area.

[0111] Before forming the mirror structure 509, the following process steps may be performed, for example: Figure 3HAs shown, a second mask layer 540 can be first formed on the surface of the epitaxial layer 530, and the second mask layer 540 can be patterned to form a first opening defining the channel between the second comb teeth 560 and a second opening defining the mirror structure 509 in the second mask layer 540, and the second mask layer 540 also defines the position and size of the second comb teeth 560 to be formed (that is, the partial position area covered by the second mask layer 540), and the position of each second comb tooth 560 corresponds to being located on a groove 510.

[0112] The material of the second mask layer 540 can be any suitable material, for example, the material of the second mask layer 540 can include silicon oxide, silicon nitride or silicon oxynitride, etc. It can be a single-layer or multi-layer film structure.

[0113] The second mask layer 540 may be formed by deposition using any suitable deposition process such as chemical vapor deposition, physical vapor deposition or atomic layer deposition. The thickness of the second mask layer 540 may be reasonably set according to actual needs and is not specifically limited herein.

[0114] The second mask layer 540 may be patterned by any suitable method, for example, a photoresist layer may be formed on the second mask layer 540, and then the photoresist layer may be patterned by a photolithography process to define the positions and sizes of the second comb teeth 560 to be formed, and the positions and sizes of the mirror structures 509, and then the second mask layer 540 may be etched using the patterned photoresist layer as a mask, and the etching may be stopped in the epitaxial layer 530 to achieve the patterning of the second mask layer 540, and then the photoresist layer may be removed. In addition to the defined positions, the second mask layer 540 also defines the positions and sizes of the channels between adjacent second comb teeth 560. Among them, the positions of the patterned second mask layer 540 and the grooves 510 correspond to each other, that is, the position of each second comb tooth 560 corresponds to a groove 510. Through such a setting, after the second comb teeth 560 are formed, the bottom of each second comb tooth 560 can be connected to a part of the first mask layer 520 (the part of the first mask layer 520 constitutes the support structure 531), and the part of the first mask layer 520 can support the second comb teeth 560. The mirror structure 509 corresponds to a plurality of grooves 510. The support structure 531 for supporting the mirror structure 509 has a plurality of grooves 510 and a first mask layer 520 filling the grooves below. The first mask layer 520 and the substrate area between the plurality of grooves 510 can support the support structure 531 and the mirror structure 509, so as to facilitate the subsequent steps such as back thinning and wet cleaning, and avoid the problem of the support structure breaking.

[0115] The mirror structure 509 may be a reflective mirror formed by a metal (e.g., one or more metal materials such as gold, silver, or aluminum). In one embodiment, the mirror structure 509 may be formed by any suitable method, such as depositing a mirror material layer to cover the epitaxial layer 530 and the second mask layer 540, and then performing a planarization process such as a chemical mechanical polishing process or etching to stop at the second mask layer 540 on the mirror material layer to form the mirror structure 509. If the pad 508 is not formed in the aforementioned steps, the pad 508 opening may be synchronously formed in the second mask layer 540, and then the pad 508 may be formed while the mirror structure 509 is formed.

[0116] In some embodiments, the mirror structure 509 can also be formed by a lift-off process. For example, a photoresist layer can be first formed on the surface of the epitaxial layer 530, the surface of the aforementioned second mask layer 540, and the surface of the pad 508. Then, a photolithography process is used to remove part of the photoresist layer to form a mirror pattern opening in the photoresist layer. The mirror pattern opening exposes part of the surface of the epitaxial layer 530. Then, a mirror material layer is deposited to cover the photoresist layer and fill the mirror pattern opening. Then, a solvent is used to dissolve the photoresist layer to lift-off the mirror material layer covering the photoresist layer, leaving only the mirror material layer deposited on the epitaxial layer, thereby forming the mirror structure 509.

[0117] In some embodiments, the method of the present application further includes: thinning the side of the substrate 500 away from the epitaxial layer 530, for example, so that the total thickness between the thinned substrate 500 and the epitaxial layer 530 reaches about 400 μm, or other suitable thicknesses. The thinning can remove a portion of the thickness of the base 501 of the substrate 500, and any suitable method can be used to thin the substrate 500, such as using one or more of chemical mechanical polishing or etching processes to achieve it.

[0118] Since the mirror structure 509 corresponds to multiple grooves 510, since there are multiple grooves 510 and a first mask layer 520 filling the grooves under the support structure 531, the first mask layer 520 and the substrate area between the multiple grooves 510 can support the support structure 531 and the mirror structure 509, making the support structure more stable. That is, compared with the related technology, the present application has no large cavity structure, thereby avoiding the risk of exposure caused by breakage of the support structure 531 during thinning.

[0119] Next, in step S270, Figure 3JAs shown, the epitaxial layer 530 is etched to form a plurality of second comb tooth 560 structures located outside the mirror structure 509 and a support structure 531 for supporting the mirror structure 509 , wherein each second comb tooth 560 structure corresponds to a groove 510 in the comb tooth area, and the plurality of second comb tooth 560 structures are located outside the support structure 531 .

[0120] For example, the second mask layer 540 can be used as a mask to etch the epitaxial layer 530 to form the second comb teeth 560 and the support structure 531 separated from the second comb teeth 560, exposing the first mask layer 520 outside the second comb teeth 560, that is, the channel outside the second comb teeth exposes the first mask layer 520.

[0121] The epitaxial layer 530 may be etched by dry etching, wet etching or any other suitable etching method, for example, the epitaxial layer 530 may be etched by deep reactive ion etching (DRIE).

[0122] Deep reactive ion etching is a process that uses high-energy ions and free radicals generated by plasma to etch silicon. It can achieve the requirements of high aspect ratio, high etching rate and high mask selectivity. The DRIE etching process can be a Bosch process, which is a cyclic etching process. Each cycle includes two steps: deposition and etching. In the deposition step, a fluorine-containing gas (such as C4F8) is used to deposit a protective film on the sidewalls and bottom of the etched area to prevent the sidewalls from being etched. In the etching step, a sulfur-containing gas (such as SF6) is used to etch silicon, and the protective film at the bottom is removed at the same time, so that the etched area extends downward. In this way, through repeated deposition and etching cycles, etching of deeper openings or grooves or channels between comb teeth can be achieved.

[0123] The second comb teeth 560 are also the top comb teeth structure, which are movable comb teeth, and the first comb teeth 550 are also the bottom comb teeth structure, which are fixed comb teeth.

[0124] In some embodiments, a protective layer may be formed before etching to cover the mirror structure 509 and the pad 508 to prevent subsequent etching from corroding them and affecting device performance. The protective layer may be a photoresist layer or a suitable material that can serve as a protective layer.

[0125] After the etching, the bottom ends of the plurality of second comb teeth 560 are respectively connected to a portion of the first mask layer 520 (i.e., a support formed by the first mask layer 520 filled in the groove 510), and the first mask layer 520 can support the second comb teeth 560, thereby making the structure of the device more stable, so that it is convenient for subsequent process steps, such as wet cleaning, etc. At the same time, the bottom of the support structure 531 is connected to a portion of the first mask layer 520, and the portion of the first mask layer 520 fills the plurality of grooves 510 and covers a portion of the surface of the substrate 500, thereby playing a good supporting role for the support structure 531, and can also make the structure of the device more stable, so that it is convenient for subsequent process steps, such as wet cleaning, etc.

[0126] Next, in step S280, continue to refer to Figure 3J , using the first mask layer 520 as a mask, etching the substrate 500 to form a plurality of first comb teeth 550 , wherein the plurality of first comb teeth 550 and the plurality of second comb teeth 560 are alternately arranged.

[0127] That is, the first mask layer 520 exposed by the channel outside the second comb teeth 560 is used as a mask to etch the substrate 500 to form the first comb teeth 550. The number of the first comb teeth 550 and the second comb teeth 560 can be multiple, and the specific number can be reasonably set according to actual needs. Multiple first comb teeth 550 and multiple second comb teeth 560 are arranged alternately.

[0128] The substrate 500 may be etched by dry etching, wet etching or any other suitable etching method, for example, the substrate 500 may be etched by deep reactive ion etching (DRIE).

[0129] Since etching residues, such as polymer residues and photoresist residues, are easily generated during the etching process of the epitaxial layer 530 and the substrate 500 (for example, etching the epitaxial layer to form the second comb teeth 560 and the support structure 531, and etching the substrate 500 to form the first comb teeth 550), if not removed, the polymer residues and photoresist residues may exist on the surface of the comb teeth, affecting the device performance. Therefore, in some embodiments, the manufacturing method of the present application further includes: after forming the first comb teeth 550 and the second comb teeth 560, and before removing the second mask layer 540 and the first mask layer 520, performing Wet cleaning is performed to remove etching residues, wherein during the cleaning process, the first mask layer 520 supports the second comb teeth 560, and through the supporting effect of the first mask layer 520 below the second comb teeth 560, the bottom of the support structure 531 is connected to a portion of the first mask layer 520, and the portion of the first mask layer 520 fills a plurality of grooves 510 and covers a portion of the substrate 500 surface, thereby providing a better support for the support structure 531, making the second comb teeth 560 and the support structure 531 more stable during wet cleaning, which is beneficial to effectively remove etching residues through wet cleaning and improve device yield and performance.

[0130] It is worth mentioning that a plurality of second comb teeth 560 are arranged in the first direction and at intervals, and the size of the second comb teeth 560 in the first direction can be equal to the size of the groove 510 in the first direction, so after etching, in the first direction, the size of the first mask layer 520 under each second comb tooth 560 is substantially the same as the size of the corresponding second comb tooth 560, or can also be larger than the size of the groove 510 in the first direction, so after etching, in the first direction, the size of the first mask layer 520 under each second comb tooth 560 is smaller than the size of the corresponding second comb tooth 560, or can also be smaller than the size of the groove 510 in the first direction, so after etching, in the first direction, the size of the first mask layer 520 under each second comb tooth 560 is larger than the size of the corresponding second comb tooth 560. In either case, it can play a supporting role for the second comb teeth 560.

[0131] Next, in step S290, Figure 3K As shown, at least the first mask layer 520 located below the second comb teeth 560 and below the support structure 531 is removed.

[0132] The first mask layer 520 under the second comb teeth 560 is removed to release the second comb teeth 560, making them movable comb teeth. At the same time, the first mask layer 520 under the mirror structure 509 can also be removed, so that there is a spacing space between the support structure 531 and the substrate 500 thereunder, so that the support structure 531 and the mirror structure 509 can be moved in the spacing space.

[0133] The second comb teeth 560 are connected to the support structure 531 , and the second comb teeth 560 can rotate along the axis of the arrangement direction thereof, thereby driving the support structure 531 and the mirror structure 509 to twist.

[0134] In some examples, continue to refer to Figure 3K , the second mask layer 540 on the second comb teeth 560 and the first mask layer 520 on the first comb teeth 550 can also be removed simultaneously.

[0135] The first mask layer 520 and the second mask layer 540 may be removed by a suitable method selected according to their materials. For example, the first mask layer 520 and the second mask layer 540 may be removed by using a buffered oxide etchant or gaseous hydrogen fluoride (VHF).

[0136] Taking the removal of the first mask layer 520 and the second mask layer 540 by using gaseous hydrogen fluoride (VHF) as an example, the basic principle of the process is: gaseous hydrogen fluoride (VHF) reacts with the first mask layer 520 and the second mask layer 540 such as silicon dioxide to generate water and hexafluorosilicic acid. Hexafluorosilicic acid reacts with silicon on the surface of the substrate 500 and the surface of the epitaxial layer 530 to generate water and silicon tetrafluoride. Silicon tetrafluoride is a volatile gas that can be exhausted from the reaction chamber to achieve etching removal of the first mask layer 520 and the second mask layer 540.

[0137] When the isolation groove is exposed and connected to the insulating layer 502, the VHF can also remove the portion of the insulating layer 502 exposed by the isolation groove.

[0138] The first mask layer 520 and the second mask layer 540 are released by gaseous hydrogen fluoride, which has a larger process window and can reduce undercutting. In addition, since the first mask layer 520 filled in the trench 510 has a filling cavity 511, it can be removed more easily, shortening the process time.

[0139] It is worth mentioning that the MEME device in the present application can be a MEMS galvanometer. The above method of the present application is only used as an example and is not strictly limited in sequence. Under the premise of no contradiction, it can be performed alternately or in reverse order.

[0140] The description of some steps of the method of the present application has been completed so far. Other steps may be included to form a complete device, which will not be repeated here.

[0141] The manufacturing method of the MEMS device provided by the present application has the following beneficial effects: by forming an epitaxial layer on the surface of the substrate and the first mask layer, and using the epitaxial layer to prepare and form the second comb teeth, compared with the related technology of using the traditional SOI wafer, the present application reduces the use of SOI wafers, so its cost is lower, the difficulty of stress regulation is reduced and the adjustment cycle is shortened. The position of each second comb tooth of the present application corresponds to a groove, and the groove is filled with the first mask layer. Then, after the first comb teeth and the second comb teeth are formed, the first mask under the second comb teeth can be used to support them, and the first hard mask layer under the support structure also supports them, thereby improving the stability of the structure, so that the subsequent process is more stable.

[0142] The present application also provides a MEMS device, which can be manufactured by the manufacturing method of the above-mentioned MEMS device. Some details of the MEMS device can refer to the relevant description above, which will not be repeated here. The MEMS device can be an optoelectronic device such as a MEM mirror drive device (also called a MEMS galvanometer).

[0143] In one example, if Figure 3K As shown, the MEMS device of the present application includes a substrate 500, the substrate 500 includes a mirror area and a comb-tooth area located outside the mirror area, a plurality of first comb teeth 550 are arranged at intervals in the comb-tooth area; a plurality of grooves 510 are arranged at intervals in the mirror area; an epitaxial layer 530 is arranged on the substrate 500, the epitaxial layer 530 includes a plurality of second comb-tooth 560 structures arranged at intervals and a support structure 531, a plurality of second comb-tooth 560 structures are located outside the support structure 531, and a plurality of second comb teeth 560 and a plurality of first comb teeth 550 are arranged alternately; a mirror structure 509 is arranged on the support structure 531, and the mirror structure 509 is opposite to the mirror area. A channel penetrating the epitaxial layer 530 is provided on the outside of each second comb tooth 560.

[0144] Exemplarily, the substrate 500 includes a base layer 501, a device layer 503, and an insulating layer 502 arranged between the base layer 501 and the device layer 503, at least two isolation grooves 507 arranged at intervals are formed in the substrate 500, and a plurality of first comb teeth 550 are arranged between adjacent isolation grooves 507, wherein the isolation grooves 507 penetrate the device layer 503 and extend into the insulating layer 502.

[0145] The MEMS device of the present application is prepared by the aforementioned method, and therefore has substantially the same advantages as the aforementioned method.

[0146] The present application has been described through the above-mentioned embodiments, but it should be understood that the above-mentioned embodiments are only for the purpose of example and illustration, and are not intended to limit the present application to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the present application is not limited to the above-mentioned embodiments, and more variations and modifications can be made according to the teachings of the present application, and these variations and modifications all fall within the scope of protection claimed by the present application. The scope of protection of the present application is defined by the attached claims and their equivalents.

Claims

1. A method for manufacturing a MEMS device, characterized in that: The following steps are involved: Providing a substrate, the substrate comprising a mirror region and a comb-tooth region located outside the mirror region; Etching the substrate to form a plurality of grooves spaced apart in the mirror region and the comb-teeth region; forming a first mask layer to cover the sidewalls of the trench, the surface of the substrate and seal the opening of the trench; Etching the first mask layer to expose a portion of the surface of the substrate and cover each region of the substrate for forming the first comb teeth and the mirror region; forming an epitaxial layer on the surface of the substrate and the first mask layer; forming a mirror structure on the epitaxial layer, wherein the mirror structure corresponds to the mirror area; Etching the epitaxial layer to form a support structure for supporting the mirror structure and a plurality of second comb teeth located outside the mirror structure, wherein each of the second comb teeth corresponds to one of the grooves in the comb tooth region, and the plurality of second comb teeth are located outside the support structure; Using the first mask layer as a mask, etching the substrate to form a plurality of the first comb teeth, wherein the plurality of the first comb teeth and the plurality of the second comb teeth are arranged alternately; At least the first mask layer located below the second comb teeth and below the support structure is removed.

2. The manufacturing method according to claim 1, characterized in that A filling cavity is also formed in the first mask layer located in the trench, wherein the top of the filling cavity is located below the surface of the substrate.

3. The manufacturing method according to claim 2, characterized in that: The forming of a first mask layer to cover the sidewalls of the trench, the surface of the substrate and seal the opening of the trench comprises: forming a first mask material layer on the sidewall of the trench and the surface of the substrate, wherein the thickness of the first mask material layer on the top sidewall of the trench is greater than that of the first mask material layer on the bottom sidewall of the trench; Etching and removing a portion of the first mask material layer so that the minimum opening of the trench is located below the surface of the substrate; forming a second mask material layer on the first mask material layer, wherein the second mask material layer seals the opening of the trench; A third mask material layer is formed on the second mask material layer, and planarization is performed to form the first mask layer, wherein the third mask material layer has a higher density than the second mask material layer.

4. The manufacturing method according to claim 1, characterized in that: Before etching the epitaxial layer to form a plurality of second comb teeth located outside the mirror structure, after forming the epitaxial layer, the manufacturing method further includes: The side of the substrate facing away from the epitaxial layer is thinned.

5. The manufacturing method according to claim 1, characterized in that: After forming the first comb teeth and the second comb teeth and before removing the first mask layer, the manufacturing method further includes: Wet cleaning is performed to remove etching residues formed when etching the epitaxial layer and the substrate, wherein during the cleaning process, the first mask layer supports the second comb teeth, and the first mask layer in the mirror area supports the supporting structure.

6. The manufacturing method according to claim 1, characterized in that: The method for forming the substrate comprises: providing a base, forming an insulating layer on the surface of the base, and epitaxially growing a device layer on the insulating layer, wherein the device layer is used to form the first comb teeth.

7. The manufacturing method according to claim 6, characterized in that: Before forming the groove, the manufacturing method further includes: forming at least two isolation trenches spaced apart from each other in the device layer; The etching of the substrate to form a plurality of grooves spaced apart in the mirror region and the comb-tooth region comprises: The device layer is etched to form a plurality of grooves spaced apart from each other in the mirror region and the comb-teeth region, and the isolation groove is etched at the same time so that the bottom of the isolation groove extends to the insulating layer.

8. The manufacturing method according to claim 1, characterized in that: The thickness of the first mask layer on the surface of the substrate is less than 1.5 μm; and / or The aspect ratio of the groove is greater than or equal to 3 and less than or equal to 60.

9. A MEMS device, characterized in that: The MEMS device comprises: A substrate, the substrate comprising a mirror region and a comb-tooth region located outside the mirror region; A plurality of first comb teeth are arranged at intervals in the comb tooth area; A plurality of grooves are arranged at intervals in the mirror surface area; An epitaxial layer is arranged on the substrate, the epitaxial layer comprises a plurality of second comb teeth arranged at intervals and a support structure, the plurality of second comb teeth are located outside the support structure, and the plurality of second comb teeth and the plurality of first comb teeth are arranged alternately; The mirror structure is arranged on the supporting structure, and the mirror structure is opposite to the mirror area.

10. The MEMS device according to claim 9, characterized in that The substrate includes a base layer, a device layer and an insulating layer arranged between the base layer and the device layer, at least two isolation grooves arranged at intervals are formed in the substrate, and a plurality of the first comb teeth are arranged between adjacent isolation grooves, wherein the isolation grooves penetrate the device layer and extend into the insulating layer.

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