MEMS device and method of manufacturing the same, electronic device

Abstract

A MEMS device and a manufacturing method thereof and an electronic device, the method comprising: providing a first substrate and a second substrate, the first substrate comprising a first region and a second region outside the first region, and the second substrate comprising a third region and a fourth region outside the third region; etching the first substrate to form a plurality of first combs at intervals in the first region; forming a plurality of second combs at intervals in the third region of the second substrate; performing a bonding process to join the first substrate with the first combs formed on one side thereof and the second substrate with the second combs formed on one side thereof to form a device substrate, and the plurality of first combs and the plurality of second combs being arranged in an interlaced manner. The method of the present application effectively reduces the generation of silicon grass, and improves the reliability, performance and service life of the MEMS device.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically to a MEMS device and its manufacturing method, and an electronic device. Background Technology

[0002] MEMS galvanometers are MEMS devices, which are miniature, drivable mirrors manufactured using Micro-Electro-Mechanical Systems (MEMS) technology. They can deflect, modulate, open / close, and control the phase of a light beam under actuation. MEMS galvanometers are lightweight, small in size, easy to mass-produce, have low production costs, and exhibit excellent optical, mechanical, and power consumption performance, making them widely used in projection, display, optical communication, and lidar applications.

[0003] As the requirements for improving the functionality and performance of MEMS mirrors increase, their structural designs are becoming increasingly complex. To increase the rotation angle of MEMS mirrors, an alternating upper and lower comb structure is designed to increase torque. However, due to the use of two deep reactive ion etching (DRIE) processes on a substrate to form the alternating comb, the polymer residue formed during the second etching process accumulates more on the comb surface, hindering further etching. This easily leads to the formation of silica fume. During MEMS mirror operation, this silica fume can damage the comb, causing short circuits, thus reducing the performance and reliability of the MEMS mirror and shortening its lifespan.

[0004] Therefore, it is necessary to propose a new MEMS device and its manufacturing method, as well as an electronic device, to at least partially solve the above problems. Summary of the Invention

[0005] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary section is not intended to limit the key and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0006] To address the existing problems, this application provides a method for manufacturing a MEMS device, comprising:

[0007] A first substrate and a second substrate are provided, the first substrate including a first region and a second region located outside the first region, and the second substrate including a third region and a fourth region located outside the third region;

[0008] The first substrate is etched to form a plurality of spaced first comb teeth in the first region;

[0009] The second substrate is etched to form a plurality of spaced second comb teeth in the third region;

[0010] A bonding process is performed to bond the side of the first substrate with the first comb teeth and the side of the second substrate with the second comb teeth to form a device substrate, wherein a plurality of the first comb teeth and a plurality of the second comb teeth are staggered with each other.

[0011] For example, a plurality of first comb teeth and a plurality of second comb teeth are arranged in an alternating nested configuration, wherein one end of the first comb teeth protrudes from the surface of the second region of the first substrate, and / or one end of the second comb teeth protrudes from the surface of the fourth region of the second substrate.

[0012] Exemplarily, the first substrate includes a base layer, an insulating layer, and a device layer stacked sequentially, and the etching of the first substrate to form a plurality of spaced-apart first comb teeth in the first region includes:

[0013] First, the device layer in the second region is etched to remove the device layer of a first predetermined thickness, then the device layer in the first region is etched to stop at the insulating layer to form a plurality of the first comb teeth; or

[0014] First, the device layer in the first region is etched to stop at the insulating layer to form a plurality of first comb teeth, and then the device layer in the second region is etched to remove the device layer of a first predetermined thickness.

[0015] Exemplarily, the second substrate includes a base layer, an insulating layer, and a device layer stacked sequentially, and the etching of the third region of the second substrate forms a plurality of spaced second comb teeth, including:

[0016] First, the device layer in the fourth region is etched to remove the device layer of the second predetermined thickness. Then, the device layer in the third region is etched, stopping at the insulating layer, to form a plurality of second comb tooth structures, or

[0017] First, the device layer in the third region is etched to stop at the insulating layer to form a plurality of second comb tooth structures. Then, the device layer in the fourth region is etched to remove the device layer of a second predetermined thickness.

[0018] For example, the first predetermined thickness ranges from 0.5 μm to 2 μm.

[0019] For example, the second predetermined thickness ranges from 0.5 μm to 2 μm.

[0020] Exemplarily, after performing the bonding process to bond the side of the first substrate with the first comb teeth and the side of the second substrate with the second comb teeth to form a device substrate, the method further includes:

[0021] The first substrate is thinned; and / or the second substrate is thinned.

[0022] For example, the first substrate includes a base layer, an insulating layer, and a device layer stacked sequentially, and the second substrate includes a base layer, an insulating layer, and a device layer stacked sequentially, wherein thinning the first substrate includes: thinning the first substrate to remove the base layer of the first substrate to expose the insulating layer of the first substrate; and / or thinning the second substrate includes: thinning the second substrate to remove the base layer of the second substrate to expose the insulating layer of the second substrate.

[0023] For example, after the thinning step, the method further includes:

[0024] The exposed insulating layer is patterned to define pad pattern openings and mirror pattern openings in the insulating layer;

[0025] A pad is formed in the opening of the pad pattern, and a mirror is formed in the opening of the mirror pattern;

[0026] Remove the exposed insulating layer to allow the first or second comb tooth to form a movable comb tooth.

[0027] Exemplarily, after forming the movable comb teeth, the method further includes:

[0028] The device substrate is etched from the side away from the mirror to form a first cavity and a second cavity, wherein the first cavity and the mirror are positioned to correspond so that the mirror can move within the first cavity, and the second cavity exposes the first comb teeth and the second comb teeth.

[0029] This application also provides a MEMS device, which is prepared according to any of the above-described MEMS device manufacturing methods.

[0030] This application also provides an electronic device, which includes the above-described MEMS device.

[0031] According to the MEMS device manufacturing method provided in this application, a first comb tooth and a second comb tooth are formed on a first substrate and a second substrate, respectively. Then, a bonding process is used to form an interlaced structure of the first comb tooth and the second comb tooth to manufacture a MEMS device. Since the comb tooth is formed by etching only once on the first substrate and the second substrate, the problem of polymer residue accumulation on the surface of the comb tooth caused by multiple etchings on a single substrate is avoided. This avoids the polymer residue from hindering the etching of the comb tooth, thereby effectively reducing the generation of silica. This allows the MEMS device to achieve large-angle rotation while improving the reliability, performance and service life of the MEMS device. Attached Figure Description

[0032] The following drawings, which are incorporated herein by reference and are used to understand this application, illustrate embodiments of the invention and their descriptions to explain the principles of the invention.

[0033] In the attached image:

[0034] Figures 1A to 1C A schematic cross-sectional view of the device obtained by sequentially implementing the manufacturing method of the MEMS galvanometer according to the relevant technology is shown;

[0035] Figure 1D A schematic diagram of the silica fume produced during the manufacturing process of a MEMS galvanometer according to the relevant technology is shown;

[0036] Figure 2 A schematic flowchart illustrating a method for manufacturing a MEMS device according to an embodiment of this application is shown;

[0037] Figures 3A to 3L A cross-sectional schematic diagram of a device obtained by sequentially implementing a method for manufacturing a MEMS device according to an embodiment of this application is shown. Detailed Implementation

[0038] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with this application.

[0039] It should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this application to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0040] 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 may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, 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., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0041] Spatial relation terms such as “below,” “under,” “below,” “below,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the galvanometer in use and operation. For example, if the galvanometer in the figure is flipped, then the element or feature described as “below,” “below,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “below” can include both above and below orientations. The galvanometer may be oriented otherwise (rotated 90 degrees or otherwise), and the spatial descriptive terms used herein will be interpreted accordingly.

[0042] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0043] Currently, methods for manufacturing MEMS galvanometers using relevant technologies include etching upper and lower comb teeth separately on the same surface of the same substrate to achieve an interlaced structure. This etching process employs DIRE etching. However, DIRE etching generates an undesirable byproduct—silica flakes (such as...). Figure 1D (As shown), these factors can affect the performance and reliability of devices. The following section combines... Figure 1A , Figure 1B and Figure 1C Describe a method for manufacturing a MEMS galvanometer based on related technologies, wherein, Figures 1A to 1C A cross-sectional schematic diagram of the device obtained by sequentially implementing the manufacturing method of MEMS galvanometers according to relevant technologies.

[0044] First, a substrate is provided, comprising a device layer 110, a buried oxide layer 120, and a base layer 130, wherein a plurality of grooves are formed on the side of the device layer 110 facing the buried oxide layer 120. Silicon dioxide (SiO2) on the surface of the device layer 110 is etched using a plasma etching (RIE) process to form a patterned hard mask layer 101. This patterned hard mask layer 101 defines the gaps between adjacent comb teeth and defines the spacing regions around the mirror structure, such as... Figure 1A As shown. Next, using the patterned hard mask layer 101 as a mask, the device layer 110 to the buried oxide layer 120 is etched using the DRIE process to form the upper comb teeth 111, and to form the gaps between adjacent comb teeth and the spacing region around the mirror structure. The upper comb teeth 111 are suspended above the buried oxide layer 120, as shown. Figure 1B As shown. Next, the comb teeth connected to the buried oxide layer 120 are etched using the DRIE process to reduce the height of the comb teeth and form the lower comb teeth 112.

[0045] Specifically, DRIE (Deep Reactive Ion Etching) is a process that uses high-energy ions and free radicals generated by plasma to etch silicon. It can achieve high aspect ratios, high etching rates, and high mask selectivity. A commonly used DRIE etching process is the Bosch process, which is a cyclic etching process. Each cycle consists of 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 the silicon, simultaneously removing the bottom protective film and extending the etched area downwards. In this way, through repeated deposition and etching cycles, trenches or vias with a depth-to-width ratio as high as 100:1 can be formed. However, in the fabrication process of MEMS galvanometers, due to the use of two DRIE etching processes on a substrate to form staggered comb teeth, the polymer residue formed during the second etching process accumulates more on the surface of the comb teeth, hindering the etching of the comb teeth and thus easily leading to the formation of silica.

[0046] Specifically, silica grass is formed when the flow rate of fluorocarbons is too high during the etching step, causing the deposition rate of the protective film to exceed the removal rate, resulting in the accumulation of the protective film at the bottom of the etched area. These deposits form carbon clusters, acting as nanomasks that hinder silicon etching, thus creating nanoscale protrusions on the silicon surface, i.e., silica grass. Silica grass formation is also influenced by other etching parameters, such as power, temperature, and time. Silica grass increases the surface roughness of the device, thereby increasing friction, wear, and stress. It also reduces the etching rate and uniformity of the device, affecting dimensional accuracy and consistency, and ultimately impacting device performance.

[0047] To address the problems existing in related technologies, this application proposes a method for manufacturing MEMS devices, which is described below in conjunction with... Figure 2 and Figures 3A to 3L Describes a method for manufacturing a MEMS device according to this application, wherein, Figure 2 A schematic flowchart illustrating a method for manufacturing a MEMS device according to an embodiment of this application is shown; Figures 3A to 3L A cross-sectional schematic diagram of a device obtained by sequentially implementing a method for manufacturing a MEMS device according to an embodiment of this application is shown.

[0048] In one embodiment, such as Figure 2 As shown, the method for manufacturing a MEMS device provided in this application includes the following steps:

[0049] Step S1: Provide a first substrate and a second substrate, wherein the first substrate includes a first region and a second region located outside the first region, and the second substrate includes a third region and a fourth region located outside the third region;

[0050] Specifically, such as Figure 3A and Figure 3B As shown, a first substrate 310 and a second substrate 320 are provided. The first substrate 310 includes a first region and a second region located outside the first region. The first substrate 310 located in the first region can be used to form a first comb tooth, while the second region can be used for subsequent bonding. The second substrate 320 includes a third region and a fourth region located outside the third region. A portion of the second substrate 320 located in the third region can be used to form a second comb tooth.

[0051] In one embodiment, the first substrate 310 and the second substrate 320 may be at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP or other III / V compound semiconductors, or the first substrate 310 and the second substrate 320 may also be silicon on insulator (SOI), silicon on insulator (SSOI), silicon on insulator (S-SiGeOI), silicon on insulator (SiGeOI) or germanium on insulator (GeOI), etc.

[0052] In a specific example, such as Figure 3A As shown, both the first substrate 310 and the second substrate 320 are SOI substrates, as... Figure 3A As shown, the first substrate 310 includes a device layer 3101, an insulating layer 3102, and a base layer 3103 stacked sequentially, wherein the insulating layer 3102 is disposed between the device layer 3101 and the base layer 3103. Figure 3B As shown, the second substrate 320 includes a device layer 3201, an insulating layer 3202 and a base layer 3203 stacked sequentially, wherein the insulating layer 3202 is disposed between the device layer 3201 and the base layer 3203.

[0053] It is worth mentioning that the first substrate 310 and the second substrate 320 can be either an SOI substrate or another type of substrate.

[0054] Furthermore, the method of this application also includes step S2: etching the first substrate to form a plurality of spaced first comb teeth in the first region.

[0055] The first comb teeth can be formed by etching the first substrate using any suitable deep silicon etching process. In one example, it can be formed by first etching the first substrate as follows: Figure 3AAs shown, first, the device layer 3101 in the second region is etched to remove the device layer 3101 of the first predetermined thickness, and then... Figure 3C As shown, the device layer 3101 in the first region is etched and stops at the insulating layer 3102 to form a plurality of first comb teeth 311. Alternatively, in other examples, the device layer 301 in the first region may be etched first and stops at the insulating layer 3102 to form a plurality of first comb teeth 311, and then the device layer 3101 in the second region may be etched to remove the device layer 3101 of the first predetermined thickness. This etching can make one end of the first comb tooth 311 protrude from the surface of the second region of the first substrate. In some other examples, the second region may not be etched, that is, one end of the first comb tooth 311 is flush with the surface of the second region of the first substrate.

[0056] Any suitable deep silicon etching process can be used to etch the device layer 3101 in the first region, stopping at the insulating layer 3102, to form a plurality of first comb teeth 311. For example, a patterned mask layer defining the shape and position of the first comb teeth 311 can be formed on the device layer 3101 in the first region, and the device layer 3101 can be etched using the patterned mask layer as a mask, stopping at the insulating layer 3102, to form a plurality of first comb teeth 311.

[0057] Optionally, the first predetermined thickness is in the range of 0.5μm-2μm, such as 0.6μm, 0.8μm, 1.0μm, 1.2μm, 1.4μm, or may be other suitable dimensions, depending on the predetermined interlocking and nesting dimensions of the first comb teeth and the predetermined second comb teeth.

[0058] At least a portion of the etched first comb teeth 311 are below the surface of the first substrate 310 located in the second region. For example, each first comb tooth 311 includes a first end and a second end opposite to the first end, wherein the first end is connected to the first substrate 310, and the second end protrudes from the surface of the first substrate 310 located in the second region. Each first comb tooth 311 extends a predetermined height along a first direction, and the plurality of first comb teeth 311 are spaced apart along a second direction, wherein the first direction is perpendicular to the surface of the first substrate 310, and the second direction is parallel to the surface of the first substrate 310. Optionally, the gap between two adjacent first comb teeth 311 is between 4 μm and 6 μm.

[0059] In some embodiments, such as Figure 3A and Figure 3CAs shown, a portion of the device layer 3101 within the second region of the first substrate 310 can also be etched to define a portion of the structure of the subsequently formed mirror (i.e., the support structure 312 for supporting the mirror layer). The formation of this support structure 312 can be performed in multiple steps, and can be performed concurrently with the formation of the first comb teeth, or some steps can be performed simultaneously with the formation of the first comb teeth 311. For example, it can be performed first as follows... Figure 3A As shown, after etching the device layer 3101 in the second region to remove the device layer 3101 of the first predetermined thickness, the region of the device layer 3101 where the mirror is to be formed is etched to form the shape of the surface of the support structure of the mirror facing away from the mirror surface. Then, as shown... Figure 3C As shown, while etching to form the first comb teeth, the device layer 3101 on the outside of the support structure 312 of the mirror can also be etched to form a gap located on the outside of the support structure 312. The etching to form the gap can be done without using the DIRE etching process.

[0060] Step S3: Etch the second substrate to form a plurality of spaced second comb teeth in the third region.

[0061] For example, a plurality of second comb teeth are at least partially embedded within the second substrate, wherein one end of the first comb tooth protrudes from the surface of the second region of the first substrate, and / or, one end of the second comb tooth protrudes from the surface of the fourth region of the second substrate. By making any one of the first comb tooth and / or the second comb tooth protrude, the first comb tooth and the second comb tooth can be staggered and nested after subsequent bonding. It is worth mentioning that the first comb tooth and the second comb tooth can also be staggered without nesting. In this case, one end of the first comb tooth can be flush with the surface of the second region of the first substrate or the end of the first comb tooth can be lower than the surface of the second region of the first substrate, and one end of the second comb tooth can be flush with the surface of the fourth region of the second substrate or the end of the second comb tooth can be lower than the surface of the fourth region of the second substrate.

[0062] The second substrate can be etched using any suitable method to form the second comb teeth. In one example, it can be done as follows: Figure 3B As shown, first, the device layer 3201 in the fourth region is etched to remove the device layer 3201 of the second predetermined thickness, and then... Figure 3DAs shown, the device layer 3201 in the third region is etched to stop at the insulating layer 3202 to form a plurality of second comb teeth 322, wherein the gap between two adjacent second comb teeth 322 is between 4μm and 6μm. Alternatively, in another example, the device layer 3201 in the third region may be etched to stop at the insulating layer 3202 to form a plurality of second comb teeth 322, and then the device layer 3201 in the fourth region may be etched to remove the second predetermined thickness of the device layer 3201. This etching can make one end of the second comb tooth 322 protrude from the surface of the fourth region of the second substrate; in some other examples, the fourth region may not be etched, that is, one end of the second comb tooth 322 is flush with the surface of the fourth region of the second substrate.

[0063] Any suitable etching method can be used to etch the device layer 3201 in the third region, stopping at the insulating layer 3202, to form a plurality of second comb teeth 322. For example, a patterned mask layer defining the shape and position of the second comb teeth 322 can be formed on the device layer 3201 in the third region, and the device layer 3201 can be etched using the patterned mask layer as a mask, stopping at the insulating layer 3202, to form a plurality of second comb teeth 322.

[0064] Optionally, the second predetermined thickness ranges from 0.5μm to 2μm, for example, 0.6μm, 0.8μm, 1.0μm, 1.2μm, 1.4μm, or may be other suitable dimensions, depending on the predetermined interlocking size of the first comb teeth and the predetermined second comb teeth. The first predetermined thickness and the second predetermined thickness may be the same or different.

[0065] At least a portion of the etched second comb teeth 322 are lower than the surface of the second substrate 320 located in the fourth region. For example, the second comb teeth 322 include a third end and a fourth end opposite to the third end, wherein the third end is connected to the second substrate 320, and the fourth end protrudes further from the surface of the second substrate 320 located in the fourth region. Each second comb tooth 322 extends a predetermined height along a first direction, and the plurality of second comb teeth 322 are spaced apart along a second direction, wherein the first direction is perpendicular to the surface of the second substrate 320, and the second direction is parallel to the surface of the second substrate 320.

[0066] It is worth noting that in the embodiment illustrated in this application, the first comb tooth 311 protrudes more from the surface of the first substrate 310 on its outer side and the second comb tooth 322 protrudes more from the surface of the second substrate 320 on its outer side. However, it is understood that either one of them can be made to protrude, and the first comb tooth 311 and the second comb tooth 322 can also be nested in an alternating manner.

[0067] Continue as Figure 3B and Figure 3CAs shown, the method of this application further includes: etching a predetermined area of ​​the device layer 3201 of the second substrate 320 corresponding to the reflector to form a cavity 3204. Optionally, the step of etching to form the cavity 3204 can be performed after the step of etching the device layer 3201 in the fourth region to remove the device layer 3201 of the second predetermined thickness, or it can be performed before that step.

[0068] Step S4: Perform a bonding process to bond the side of the first substrate with the first comb teeth and the side of the second substrate with the second comb teeth to form a device substrate, and the plurality of first comb teeth and the plurality of second comb teeth are staggered with each other.

[0069] In a specific example, such as Figure 3E As shown, a bonding process is performed to bond the first substrate 310 with the first comb teeth 311 and the second substrate 320 with the second comb teeth 322 together to form a device substrate 300. The plurality of first comb teeth 311 and the plurality of second comb teeth 322 are arranged in an alternating nested configuration. This alternating nested configuration means that the first comb teeth 311 and the second comb teeth 322 are arranged alternately along a direction parallel to the surface of the device substrate 300, and the first comb teeth 311 extend into the gaps between adjacent second comb teeth 322, and the second comb teeth 322 extend into the gaps between adjacent first comb teeth 311. Figure 3F As shown; wherein, the side of the first substrate 310 with the first comb teeth 311 is bonded to the side of the second substrate 320 with the second comb teeth 322, for example, the surface of the first substrate 310 located in the second region is bonded to the surface of the second substrate 320 located in the fourth region.

[0070] Various bonding processes are employed in MEMS device manufacturing. Depending on the materials and structure, a suitable bonding method can be selected. Generally, commonly used bonding processes include silicon-silicon bonding and conductive adhesive bonding. Silicon-silicon bonding is a technique that connects two clean, flat silicon wafers together under certain conditions through surface chemical bonds. Silicon-silicon bonding is often combined with surface silicon processing and bulk silicon processing in MEMS fabrication. Conductive adhesive bonding utilizes a conductive adhesive as an intermediate dielectric layer, connecting two wafers together through low temperature and low pressure. This bonding process is suitable for joining dissimilar materials and has advantages such as low temperature, low cost, and simple operation. For example, those skilled in the art can select a suitable bonding process according to actual needs; this application does not limit this selection, but aims to bond the first substrate 310 and the second substrate 320, and to arrange the first substrate 310 and the second substrate 320 into the following configuration: Figure 3F The device substrate 300 with an integrated structure is shown.

[0071] In one embodiment, before bonding the first surface of the first substrate 310 to the first surface of the second substrate 320, the first substrate 310 and the second substrate 320 are aligned, such as... Figure 3E As shown, the first comb tooth 311 is aligned with the gap of the adjacent second comb tooth 322, and the second comb tooth 322 is aligned with the gap of the adjacent first comb tooth 311.

[0072] Alignment in MEMS device manufacturing can generally be achieved using optical alignment, which utilizes markings or patterns on the wafer for alignment.

[0073] In this application, the first comb teeth 311 and the second comb teeth 322 are formed by etching the first substrate and the second substrate respectively, and then the first substrate and the second substrate are combined into one. Since the comb teeth are formed by etching only once on the first substrate and the second substrate respectively, there is no polymer residue accumulated on the surface of the comb teeth due to secondary etching, which avoids the polymer residue from hindering the etching of the comb teeth, thus making it less likely to cause silicon ash formation, thereby improving the performance and reliability of the device.

[0074] Furthermore, in order to fabricate MEMS devices, the manufacturing method of this application further includes the following steps: thinning the first substrate 310; and / or thinning the second substrate 320. The specific thinning of the first substrate 310 or the second substrate 320 can be reasonably set according to the actual situation, or both the first substrate 310 and the second substrate 320 can be thinned.

[0075] In a specific example, such as Figure 3G As shown, the first substrate 310 is thinned to remove the base layer 3103 of the first substrate 310, exposing the insulating layer 3102 of the first substrate 310. Any suitable method can be used to thin the substrate, such as one or more of mechanical polishing, chemical mechanical polishing, or etching processes. For example, a chemical mechanical polishing process and a wet etching process can be used to thin the first substrate 310 to a predetermined thickness. The mechanical polishing process is performed so that the first substrate 310 still retains the buried oxide layer 3102 and part of the base layer 3103. The wet etching process is performed to remove the base layer 3103 and expose the insulating layer 3102, resulting in the desired thinning. Figure 3G The structure shown.

[0076] Furthermore, after thinning, the method of this application further includes the following steps: patterning the exposed insulating layer to define pad pattern openings and mirror pattern openings in the insulating layer; forming pads in the pad pattern openings and forming mirrors in the mirror pattern openings; removing the exposed insulating layer to make the first comb tooth or the second comb tooth form movable comb teeth.

[0077] In a specific example, after thinning the first substrate 310, as... Figures 3H to 3J As shown, the insulating layer 3102 of the exposed first substrate 310 is patterned to define pad pattern openings and mirror pattern openings in the insulating layer 3102. Pads 330 are then formed in the pad pattern openings, and mirrors 340 are formed in the mirror pattern openings. The pads 330 can be formed first, followed by the mirrors 340, or vice versa, or both can be formed simultaneously. The mirrors and pads are formed on the first substrate 310 outside the first comb teeth 311. Optionally, the number of pads can be one or more, and the pads can be used to electrically connect the first and second comb teeth to external circuitry.

[0078] The mirror can be a reflective mirror formed of a metal (such as one or more metallic materials such as gold, silver, or aluminum). In one embodiment, the mirror can be formed by any suitable method, such as depositing a mirror material layer on the insulating layer 3102 of the first substrate, and then performing a planarization process, such as a chemical mechanical polishing process, on the mirror material layer to form the mirror 340, and pads can also be formed at the same time.

[0079] In one example, taking the first comb tooth 311 as a movable comb tooth as an example, in order to make the first comb tooth 311 movable, it is necessary to remove the exposed insulating layer 3102 of the first substrate 310 so that the first comb tooth 311 forms a movable comb tooth. The first comb tooth can be along the first comb tooth arrangement direction (i.e. Figure 3J The axis (in the XX direction) rotates, and the first comb tooth can be connected to the mirror 340, thereby driving the mirror 340 to rotate. Any suitable method can be used to remove the insulating layer 3102, such as hydrofluoric acid vapor etching or wet etching processes to remove the exposed insulating layer 3102. Taking hydrofluoric acid vapor etching to remove the insulating layer as an example, hydrofluoric acid vapor etching is a process that uses hydrofluoric acid vapor to etch silicon wafers, effectively avoiding adhesion problems and improving MEMS performance. The basic principle of this process is: the device substrate 300 is placed in a sealed reaction chamber, and hydrofluoric acid vapor is generated by heating. The hydrofluoric acid vapor reacts with the insulating layer 3102, such as silicon dioxide, on the substrate surface to generate water and hexafluorosilicic acid. The hexafluorosilicic acid reacts with the silicon on the surface of the device substrate 300 to generate water and silicon tetrafluoride. Silicon tetrafluoride is a volatile gas that can be discharged from the reaction chamber, achieving the etching of the insulating layer 3102.

[0080] Furthermore, to increase the movement space of the mirror surface, after forming the movable comb teeth, the method of this application further includes: as follows Figure 3K and Figure 3LAs shown, a first cavity 361 and a second cavity 362 are formed by etching the device substrate 300 from the side opposite to the mirror surface 340. The first cavity 361 and the mirror surface 340 are positioned correspondingly so that the reflector with the mirror surface 340 can move within the first cavity 361. The second cavity 362 exposes the first comb teeth 311 and the second comb teeth 322, thereby increasing the movement space of the comb teeth. The first cavity 361 and the second cavity 362 can be formed simultaneously or sequentially.

[0081] Optionally, the first cavity 361 can be formed by one or more etching steps. For example, the second cavity 362 can be formed simultaneously. For example, the base layer 3203 of the second substrate 320 can be etched first until the insulating layer 3202 is exposed, and then the exposed insulating layer 3202 can be removed by etching, for example by hydrofluoric acid vapor etching or wet etching process. At this time, the second cavity 362 is formed. The second cavity 362 is connected to the cavity 3204 formed in the previous step, and a gap is formed on the outside of the reflector. Therefore, the reflector can move in the space formed by the cavity 3204 and the second cavity 362.

[0082] It is worth mentioning that this application mainly uses MEMS galvanometer as an example to describe the method of this application. However, it is understood that the method of this application can also be applied to other MEMS devices that need to form an interlaced comb structure. The above method is only an example and there is no strict order limit. Under the premise of not contradicting each other, it can be performed alternately or in a different order.

[0083] This concludes the description of some steps of the method in this application. Other steps may be included to form a complete device, which will not be elaborated here.

[0084] The MEMS device manufacturing method provided in this application has the following beneficial effects: by forming the first comb tooth and the second comb tooth on the first substrate and the second substrate respectively, and then using a bonding process to form an interlaced structure of the first comb tooth and the second comb tooth, a MEMS device is manufactured. Since the comb tooth is formed by etching only once on the first substrate and the second substrate respectively, the problem of polymer residue accumulation on the surface of the comb tooth caused by multiple etchings on a single substrate is avoided. This avoids the polymer residue hindering the etching of the comb tooth, thereby effectively reducing the generation of silicon dust. This allows the MEMS device to achieve large-angle rotation while improving the reliability, performance and service life of the MEMS device.

[0085] This application also provides a MEMS device, which can be manufactured by the above-described MEMS device manufacturing method. The following is in conjunction with... Figure 3L The MEMS devices provided in the embodiments of this application will be further described.

[0086] In one embodiment, such as Figure 3L As shown, the MEMS galvanometer 400 includes a first substrate 310 and a second substrate 320, a plurality of first comb teeth 311 spaced apart on the first substrate 310, a plurality of second comb teeth 322 spaced apart on the second substrate 320, a mirror surface and a pad disposed on the second surface of the first substrate 310, and a first cavity 361 and a second cavity 362 disposed on one side of the second surface of the second substrate 320; wherein, the first surface of the first substrate 310 and the first surface of the second substrate 320 are bonded to each other, and the first comb teeth 311 and the second comb teeth 322 form an interleaved structure. Exemplarily, the first comb teeth 311 extend into the gap between adjacent second comb teeth 322, and the second comb teeth 322 extend into the gap between adjacent first comb teeth 311, that is, the first comb teeth 311 and the second comb teeth 322 are arranged alternately and nested. Optionally, the plurality of first comb teeth 311 may have substantially the same height, which refers to the dimension in the direction perpendicular to the surface of the first substrate. Alternatively, in some embodiments, the dimensions of the first comb teeth may be substantially the same or different, or partially the same and partially different, in the arrangement direction of the plurality of first comb teeth 311.

[0087] Optionally, the plurality of second comb teeth 322 may have substantially the same height, which refers to the dimension in the direction perpendicular to the surface of the second substrate 320. Alternatively, in some embodiments, the dimensions of the second comb teeth 322 may be substantially the same or different, or partially the same and partially different, in the arrangement direction of the plurality of second comb teeth 322.

[0088] In some embodiments, the first surface of the first substrate 310 is bonded to the first surface of the second substrate 320. For example, the first substrate 310 and the second substrate 320 may be directly bonded, or they may be indirectly bonded through a bonding layer, which may include an oxide layer or other suitable materials.

[0089] In one embodiment, the MEMS device of this application can be a MEMS mirror, which can be an electrostatic comb-driven MEMS mirror. This electrostatic comb-driven MEMS mirror includes a rotatable mirror (i.e., mirror surface 340 and the device layer covered by the mirror surface) and interlaced comb teeth (i.e., first comb teeth 311 and second comb teeth 322). The mirror is a thin sheet made of silicon or other materials, one side of which is coated with metal or other reflective material. The mirror is also connected to a cantilever beam or other supporting structure. The comb teeth are respectively arranged around the mirror to form a parallel plate capacitor. When an alternating voltage is applied to the comb teeth, an electrostatic field is formed between the comb teeth, generating electrostatic force. The comb teeth are subjected to this electrostatic force, generating torque and rotating. Simultaneously, the comb teeth drive the mirror to rotate axially and perform angular scanning, thereby changing the direction of the reflected beam and achieving beam deflection. The shape, number, and spacing of the comb teeth affect the electrostatic force and driving displacement of the comb teeth. The advantages of electrostatic comb-driven MEMS galvanometers include simple structure, low driving voltage, fast response speed, low power consumption, high reliability, high sensitivity, and easy integration.

[0090] The MEMS galvanometer provided in this application has the following advantages: By defining the first comb tooth and the second comb tooth on the first substrate and the second substrate respectively, and then using a bonding process to form an interlaced structure of the first comb tooth and the second comb tooth, the MEMS galvanometer is manufactured. Therefore, while the MEMS galvanometer can achieve large-angle rotation, the manufacturing method of the MEMS galvanometer provided in this application does not generate silica during the manufacturing process, which improves the reliability of the MEMS galvanometer. At the same time, it increases the field of view of the MEMS galvanometer, improves the scanning speed of the MEMS galvanometer, and improves the control accuracy of the beam or image. In summary, the MEMS galvanometer provided in this application has better performance and a longer service life.

[0091] This application also provides an electronic device including the above-described MEMS device, wherein the MEMS device is the MEMS device described in the above embodiments, or a MEMS device manufactured according to the above-described MEMS device manufacturing method.

[0092] For example, taking a MEMS galvanometer as an example, the electronic device provided in this application may include the following parts: a MEMS galvanometer, a driving circuit, a laser source, an optical system, a control system, and a housing. The MEMS galvanometer is the core component of the electronic device, determining the scanning range, speed, resolution, and stability of the light beam. The driving circuit provides voltage or current signals to the MEMS galvanometer and needs to be compatible with its operating mode and driving method. The laser source provides optical signals to the electronic device and needs to be compatible with the optical characteristics and application requirements of the MEMS galvanometer. The optical system provides optical elements to the electronic device and needs to be coordinated with the optical parameters of the MEMS galvanometer and the scanning method of the light beam. The control system provides control signals and data processing for the electronic device and needs to be compatible with the control interface and application functions of the MEMS galvanometer. The housing provides protection and fixation for the electronic device and needs to be compatible with the size and shape of the MEMS galvanometer.

[0093] The electronic device provided in this application can be any electronic product or device with similar functions or performance, such as lidar, laser projector, laser sensor, laser display, VR / AR device, etc., or any intermediate product including the aforementioned MEMS galvanometer. Lidar is a device that uses a laser beam to detect and measure targets. A lidar including the aforementioned MEMS galvanometer can scan by changing the emission angle of a single transmitter, thereby forming a scanning field of view of an array. This type of lidar has the advantages of small size, light weight, low power consumption, fast scanning speed, high resolution, and good stability, and is suitable for scenarios including autonomous driving, drones, and robots. A laser projector is a device that uses a laser beam to project images onto a screen or wall. A laser projector including the aforementioned MEMS galvanometer can quickly scan the laser beam to form a high-definition image. This type of laser projector has high brightness, vivid colors, strong contrast, and long projection distance. The advantages of long lifespan make it suitable for scenarios including home theaters, commercial presentations, and education and training. A laser sensor is a device that uses a laser beam to detect and measure physical or chemical quantities. Laser sensors, including the aforementioned MEMS galvanometers, can achieve precise measurement of targets by modulating and controlling the laser beam. These laser sensors have advantages such as high sensitivity, high accuracy, strong anti-interference ability, and fast response speed, making them suitable for scenarios including medical, environmental, and security applications. A laser display is a display device that uses laser light sources and MEMS galvanometers to project images directly onto the human retina or other media. Laser displays including the aforementioned MEMS galvanometers can achieve high-speed, high-precision, and large-angle beam scanning, thereby achieving high-resolution, high-brightness, and high-contrast laser displays. Applications of laser displays include smart glasses, head-up displays, holographic projection, and 3D depth cameras. VR devices are devices that utilize virtual reality (VR) technology. VR (Virtual Reality) technology places users in a fully immersive virtual environment, allowing them to experience a sense of presence. AR (Augmented Reality) devices utilize Augmented Reality (AR) technology to overlay virtual objects onto real-world scenes, providing users with a combined virtual and real experience. VR / AR devices are typically wearable glasses or helmets, but can also be non-wearable devices such as mobile phones or tablets. They can use screens, lenses, sensors, cameras, projectors, and optical systems to present and interact with virtual environments, as well as generate and locate virtual objects. VR / AR devices, including the aforementioned MEMS galvanometers, can achieve precise control of laser beams, thereby realizing the presentation of virtual and augmented reality images. Applications of such VR / AR devices include education, entertainment, healthcare, gaming, and the metaverse. In summary, the electronic device provided in this application, due to the use of the aforementioned MEMS galvanometers, has better performance.

[0094] This application has been described through the above embodiments. However, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit this application to the scope of the described embodiments. Furthermore, those skilled in the art will understand that this application is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of this application, all of which fall within the scope of protection claimed in this application. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing a MEMS galvanometer, characterized in that, Includes the following steps: A first substrate and a second substrate are provided. The first substrate includes a first region and a second region located outside the first region. The second substrate includes a third region and a fourth region located outside the third region. The first substrate includes a base layer, an insulating layer and a device layer stacked sequentially. The second substrate includes a base layer, an insulating layer and a device layer stacked sequentially. The first substrate is etched to form a plurality of spaced first comb teeth in the first region; The second substrate is etched to form a plurality of spaced second comb teeth in the third region; A bonding process is performed to bond the side of the first substrate with the first comb teeth and the side of the second substrate with the second comb teeth to form a device substrate, and the plurality of first comb teeth and the plurality of second comb teeth are arranged alternately to each other. The first substrate is thinned to remove the base layer of the first substrate and expose the insulating layer of the first substrate; and / or the second substrate is thinned to remove the base layer of the second substrate and expose the insulating layer of the second substrate. The exposed insulating layer is patterned to define pad pattern openings and mirror pattern openings in the insulating layer; A pad is formed in the opening of the pad pattern, and a mirror is formed in the opening of the mirror pattern; Remove the exposed insulating layer to allow the first or second comb tooth to form a movable comb tooth.

2. The method for manufacturing a MEMS galvanometer as described in claim 1, characterized in that, A plurality of first comb teeth and a plurality of second comb teeth are arranged in an alternating nested configuration, wherein one end of a first comb tooth protrudes from the surface of the second region of the first substrate, and / or one end of a second comb tooth protrudes from the surface of the fourth region of the second substrate.

3. The method for manufacturing a MEMS galvanometer as described in claim 1 or 2, characterized in that, The first substrate includes a base layer, an insulating layer, and a device layer stacked sequentially. Etching the first substrate to form a plurality of spaced-apart first comb teeth in the first region includes: First, the device layer in the second region is etched to remove the device layer of a first predetermined thickness, then the device layer in the first region is etched to stop at the insulating layer to form a plurality of the first comb teeth; or First, the device layer in the first region is etched to stop at the insulating layer to form a plurality of first comb teeth, and then the device layer in the second region is etched to remove the device layer of a first predetermined thickness.

4. The method for manufacturing a MEMS galvanometer as described in claim 1 or 2, characterized in that, The second substrate includes a base layer, an insulating layer, and a device layer stacked sequentially. Etching the second substrate to form a plurality of spaced-apart second comb teeth in the third region includes: First, the device layer in the fourth region is etched to remove the device layer of the second predetermined thickness. Then, the device layer in the third region is etched, stopping at the insulating layer, to form a plurality of second comb tooth structures, or First, the device layer in the third region is etched to stop at the insulating layer to form a plurality of second comb tooth structures. Then, the device layer in the fourth region is etched to remove the device layer of a second predetermined thickness.

5. The method according to claim 3, characterized in that, The first predetermined thickness is in the range of 0.5μm-2μm.

6. The method according to claim 4, characterized in that, The second predetermined thickness ranges from 0.5 μm to 2 μm.

7. The method according to claim 1, characterized in that, After forming the movable comb teeth, the method further includes: The device substrate is etched from the side away from the mirror to form a first cavity and a second cavity, wherein the first cavity and the mirror are positioned to correspond so that the mirror can move within the first cavity, and the second cavity exposes the first comb teeth and the second comb teeth.

8. A MEMS device, characterized in that, The MEMS device is prepared using the method described in any one of claims 1 to 7.

9. An electronic device, characterized in that, Includes the MEMS device as described in claim 8.

Images