WO2020237640A1

WO2020237640A1 - Mems device and preparation method therefor, and electronic device

Info

Publication number: WO2020237640A1
Application number: PCT/CN2019/089575
Authority: WO
Inventors: 罗松成; 詹竣凯; 游博丞; 谢冠宏; 方维伦
Original assignee: 万魔有限公司
Priority date: 2019-05-31
Filing date: 2019-05-31
Publication date: 2020-12-03
Also published as: CN113348145A

Abstract

A MEMS device, an electronic device comprising the MEMS device, and a preparation method for the MEMS device, a thin film structure (10) of the MEMS device comprising a first rigid area (110) having a first rigidity positioned in a middle area and a second rigid area (120) having a second rigidity positioned in an edge area, the first rigidity being less than the second rigidity, and the second rigid area comprising at least one protrusion (122) extending outward from the surface of the thin film structure (10). The preparation method of the MEMS device comprises: providing a substrate (210); forming a trench (212) on the substrate (210); and providing the thin film structure (10). By means of increasing the process margin during reaming of the support structure, the MEMS device ensures that the rigidity of the first rigid area (110) of the thin film structure will not be substantially changed as a result of reaming error, in order to avoid affecting the performance of the MEMS device.

Description

MEMS equipment, preparation method thereof, and electronic equipment

Technical field

The present invention relates to the field of MEMS technology, in particular to a MEMS device, a preparation method thereof, and an electronic device.

Background technique

MEMS (Micro-Electro-Mechanical System, Micro-Electro-Mechanical System) technology is a combination of semiconductor manufacturing processes and other micro-machining methods to manufacture and integrate optical and electromechanical components on a chip. However, during the formation of the back hole of the support structure in the traditional MEMS device, the rigidity of the thin film structure on the support structure is often changed due to the hole reaming error, which affects the performance of the MEMS device during use.

Summary of the invention

According to various embodiments of the present application, a MEMS device, a manufacturing method thereof, and an electronic device are provided.

A MEMS device including:

The film structure includes a first rigid area with a first rigidity in the middle area and a second rigid area with a second rigidity in the edge area, the first rigidity is less than the second rigidity, the second rigid area It includes at least one protrusion extending outward from the surface of the film structure.

An electronic device includes a device body, and further includes any of the above MEMS devices arranged on the device body.

A method for preparing MEMS equipment includes:

Provide substrate;

Forming a groove on the substrate;

A film structure is provided, the film structure includes a first rigid area with a first rigidity located in a middle area and a second rigid area with a second rigidity located in the edge area, the first rigidity is less than the second rigidity, so The second rigid area includes at least one protrusion formed in the groove.

In the above-mentioned MEMS device, by providing at least one protrusion extending outward from the surface of the thin film structure in the second rigid area located in the edge area, the process margin when the supporting structure supporting the thin film structure is reamed is increased. When the hole position is offset and the reaming is too large and the position is shifted, the rigidity of the first rigid area can still be guaranteed to be relatively stable, and the rigidity of the first rigid area of the film structure will not be substantially changed due to the reaming error, which will affect For the performance of the MEMS device during use, the protrusions of the second rigid area further extend into the inside of the support structure to strengthen and fix the membrane structure.

The first rigid area is provided with ribs extending outward from the surface of the film structure to divide the first rigid area into sub-areas with different rigidities, or at least two sub-areas with the same rigidity, and the detection capability of the sub-areas with the same rigidity The same and different sub-regions with different rigidity have different detection capabilities. Compared with the MEMS device in the preparation of the thin film structure, depositing multiple layers and etching them to make them have multiple rigidities, in the above-mentioned MEMS device, the convex area is set in the first rigid area. Ribs can be divided into multiple sub-regions with different rigidity or part of the same rigidity, which can avoid process errors and cost increases caused by multilayer structures and etching processes; part of the ribs in the first rigid region extends to the support structure Inside, it further strengthens and fixes the membrane structure.

In the above-mentioned preparation method of the MEMS device, the substrate is used as the support structure of the thin film structure, and the second rigid area at the edge area of the thin film structure is formed at least one protrusion in the groove by forming a groove on the substrate, which increases the time when the substrate is expanded. When the reaming is too large, the reaming position is offset, and the reaming is too large and the position is shifted, the rigidity of the first rigid area of the film structure is still relatively stable, and the first rigid area of the film structure will not be caused by the reaming error. The rigidity of a rigid area changes substantially, which affects the performance of the MEMS device during use; and using the same deposition process, a single deposition of semiconductor material can produce the thin film structure and the protrusions included in the second rigid area with higher accuracy , And reduce yellow light and etching process, the process flow is simpler.

The protrusions of the first rigid area and the ribs of the second rigid area of the thin film structure can be made at the same time by etching grooves in the corresponding areas of the substrate and backfilling the grooves, which improves the production margin during substrate etching Furthermore, the first rigid area of the thin film structure is divided into a plurality of sub-areas, and the rigidity of each sub-area can be made different by forming grooves with different structures or protrusions with different structures in each sub-area.

The details of one or more embodiments of the application are set forth in the following drawings and description. Other features, purposes and advantages of this application will become apparent from the description, drawings and claims.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, the drawings of other embodiments can be obtained based on these drawings without creative work.

Figure 1 is a cross-sectional view of the MEMS device when the reaming position is normal.

Figure 2 is a cross-sectional view of the MEMS device when the reamed hole is too large.

Fig. 3 is a cross-sectional view of the MEMS device when the reaming position is shifted.

4 is a cross-sectional view of the MEMS device in an embodiment when the reaming position is normal.

Fig. 5 is a schematic diagram of a fixed end and a flexible structure in an embodiment.

Fig. 6 is a top view of the MEMS device in the embodiment of Fig. 4 when the reaming position is normal.

FIG. 7 is a top view of the MEMS device in an embodiment when the reamed hole is too large.

FIG. 8 is a top view of the MEMS device in an embodiment when the reamed hole is too large and the position is shifted.

9 is a cross-sectional view of the MEMS device in the embodiment of FIG. 7 when the reamed hole is too large.

10 is a cross-sectional view of the MEMS device in the embodiment of FIG. 8 when the reamed hole is too large and the position is shifted.

Fig. 11 is a top view of the MEMS device in the second embodiment.

Fig. 12 is a top view of the MEMS device in the third embodiment.

Fig. 13 is a flow chart of a method for preparing a MEMS device in an embodiment.

FIG. 14 is a cross-sectional view of the substrate provided in step S100 in an embodiment.

FIG. 15 is a cross-sectional view of the substrate provided in step S200 in an embodiment.

FIG. 16 is a cross-sectional view of the supporting structure formed in step S300 in an embodiment.

FIG. 17 is a cross-sectional view of the MEMS device formed in step S400 in an embodiment.

FIG. 18 is a cross-sectional view of the MEMS device formed in step S500 in an embodiment.

FIG. 19 is a cross-sectional view of the MEMS device formed in step S600 in an embodiment.

Fig. 20 is a cross-sectional view of a MEMS device in another embodiment.

Detailed ways

In order to make the purpose, technical solutions, and advantages of this application clearer, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the application, and are not used to limit the application.

In the description of this application, it should be understood that the terms "center", "lateral", "upper", "lower", "left", "right", "vertical", "horizontal", "top", " The orientation or positional relationship indicated by “bottom”, “inner”, and “outer” are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, rather than indicating or implying the device or The element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. In addition, it should be noted that when an element is referred to as being "formed on another element", it may be directly connected to another element or a centering element may exist at the same time. When an element is considered to be "connected" to another element, it can be directly connected to the other element or an intermediate element can exist at the same time. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements.

In MEMS devices, a support structure is often placed under the membrane structure to support the membrane structure to deform the membrane structure under pressure such as air sound pressure changes or mechanical vibrations, so as to measure changes in these physical quantities. Reaming the hole in the support structure to form a back hole for the exposed film structure. The film structure deforms in the area opposite to the back hole, that is, the area of the film structure opposite to the back hole is a flexible structure, which is opposite to the support structure. The membrane structure area is the fixed end. In the process of reaming the support structure, the variation of the back hole etching and double-sided yellow light alignment accuracy on the support structure is not easy to control due to the influence of the etching tilt angle, and the reaming is too large and the reaming position is offset. Shift and so on. As shown in Figure 1 to Figure 3, the dotted line in the figure is the normal position of the reaming position, and the solid line is the actual reaming position. When the reaming position is normal, the reaming is too large, and the reaming is too large and the position is offset, the rigidity of the flexible structure in the membrane structure is rigid 1, rigid 2 and rigid 3 respectively, that is, the reaming error is easy to cause the flexible structure The rigidity of the MEMS device has undergone a substantial change, which affects the performance of the MEMS device during use.

In order to solve the problem that the rigidity of the flexible structure in the thin film structure changes due to the hole expansion error of the support structure in the traditional MEMS device, this application proposes a new MEMS device.

In the first embodiment, as shown in FIG. 4, a MEMS device includes a thin film structure 10. The film structure 10 includes a first rigid area 110 with a first rigidity located in the middle area and a second rigid area 120 located in the edge area. The first rigidity is smaller than the second rigidity, that is, the rigidity of the second rigid region 120 of the membrane structure 10 is greater than the rigidity of the first rigid region 110. When the membrane structure 10 is subjected to pressure such as mechanical vibration or air sound waves, the first rigid area 110 is deformed, that is, the first rigid area 110 serves as the detection area of the membrane structure 10. The first rigid area 110 that is the detection area is relatively stable and is not affected by the second rigid area 120. The second rigid area 120 includes at least one protrusion 122 extending outward from the surface of the film structure 10. The number of protrusions 122 may be one or more. The position of the protrusion 122 of the second rigid area 120 determines the boundary of the first rigid area 110, that is, the boundary of the deformable area of the thin film structure 10, that is, the boundary of the detection area. In this embodiment, the protrusion 122 of the second rigid region 120 is a rib-shaped structure, and when viewed from the top view, it extends out of a circle, a rectangle, a polygon, etc., and these shapes may be closed or open. In other embodiments, the protrusions 122 of the second rigid region 120 may also have discrete structures, such as multiple independent columnar structures. The protrusions 122 may all extend outward from the same surface of the thin film structure 10 or may extend outward from different surfaces of the thin film structure 10. In this embodiment, the MEMS device further includes a supporting structure 20. The membrane structure 10 is partially located on the supporting structure 20, and the supporting structure 20 is provided with a back hole for exposing the first rigid area 110. Between the dotted line and the solid line in Figure 4 is the position of the pre-expanded hole to form the back hole. Since the second rigid area 120 is provided with the protrusion 122, a boundary is formed between the first rigid area 110 and the second rigid area 120 to distinguish the fixed end from the flexible part, see FIG. 5.

The above-mentioned MEMS device is provided with at least one protrusion 122 extending outward from the surface of the thin film structure 10 in the second rigid area 120 located in the edge area, which can increase the process margin when the support structure 20 supporting the thin film structure 10 is reamed. When the hole is too large, the reaming position is offset, and the reaming is too large and the position is offset, the rigidity of the first rigid area 110 can still be ensured, and the first rigid area 110 of the film structure 10 will not be affected by the reaming error. The rigidity changes substantially, which affects the performance of the MEMS device.

In one embodiment, the aforementioned MEMS device further includes a back plate (also referred to as a back plate) disposed at least partially opposite to the thin film structure 10 to form a capacitor structure with the thin film structure 10. Wherein, a fixed structure such as a connecting column may be provided between the film structure 10 and the back plate for connection, or a fixed structure may be provided at the edge area of the film structure 10 and the back plate for support. There is a gap between the film structure 10 and the back plate, such as an air gap. The MEMS electronic device can detect the physical quantity that can deform the thin film structure 10. For example, the MEMS device is a MEMS sound sensor. Air sound pressure changes, mechanical vibrations, etc. deform the first rigid region 110 of the thin film structure 10, thereby detecting sound . Mechanical vibration can be the vibration of bones such as ear bones or other solids caused by sound or mechanical external forces. When the MEMS device detects sound, the sound will cause changes in the sound pressure of the air, and the change in air pressure below the membrane structure 10 directly drives it to vibrate to produce deformation. At this time, because the distance between the thin film structure 10 and the backplane changes, a changed capacitance is generated, and the detection of physical quantities such as sound waves or vibrations that can cause the thin film structure 10 to deform.

It can be understood that the dotted line in the outermost layer in FIGS. 6, 7 and 8 is the actual reaming position, and the solid line is the boundary between the first rigid area 110 and the second rigid area 120. The position between the two dotted lines in Fig. 6 is the position of the pre-expansion. The actual expansion in Fig. 7 is larger than the pre-expansion. The actual expansion in Fig. 8 is larger than the pre-expansion and the position is offset. 4 is a cross-sectional view of FIG. 6 in the direction of AA', FIG. 9 is a cross-sectional view of FIG. 7 in the direction of BB', and FIG. 10 is a cross-sectional view of FIG. 8 in the direction of CC'. With reference to FIGS. 4 to 10, it can be seen that the protrusion 122 provided in the second rigid area 120 of the film structure 10 defines the boundary between the first rigid area 110 and the second rigid area 120, regardless of whether the reaming is too large or reaming If the position is shifted or the reaming is too large and the position is shifted, the rigidity of the first rigid region 110 can still be maintained without substantial change due to the reaming error.

In the second embodiment, as shown in FIG. 11, the first rigid region 110 includes a plurality of sub-regions, and the rigidity of each sub-region is less than the second rigidity. In this embodiment, the first rigid area 110 is divided into a plurality of sub-areas by providing a rib 112 extending outward from the surface of the film structure 10 in the first rigid area 110. The rib 112 may be one or more elongated rib wall structures extending from one end to the other end of the membrane structure 10, or may be a closed loop or irregular shape in the first rigid region 110. The plurality of sub-regions may be asymmetrical, or the rib 112 may be arranged in the center of the film structure 10 to divide the first rigid region 110 into a plurality of symmetrical sub-regions. In other embodiments, the first rigid region 110 includes a plurality of independent film structures, and each independent film structure forms a sub-region.

In an embodiment, at least two sub-regions in the plurality of sub-regions have the same rigidity. For example, the first rigid region 110 includes a third rigid sub-region 113 having a middle region and a plurality of fourth rigid sub-regions 114 around it, see FIG. 11. The rigidity of the third rigid sub-region 113 is the third rigidity, and the rigidity of the fourth rigid sub-region 114 is the fourth rigidity. When the MEMS device is used to detect physical quantity changes, the detection capabilities of multiple fourth rigid sub-regions 114 are the same, and the detection capabilities of the third rigid sub-region 113 in the middle region and the fourth rigid sub-region 114 around it are different. In other embodiments, a plurality of sub-regions with the same rigidity may be provided in the middle region, and a sub-region having different rigidity from the sub-region of the middle region may be provided around it. The first rigidity of the membrane structure 10 in this embodiment is the overall rigidity of the first rigid region 110, and the third rigidity and the fourth rigidity are the rigidities of different sub-regions respectively.

In the third embodiment, the rigidity of each sub-region is different, such as the rigidity of the fifth rigid sub-region 115, the sixth rigid sub-region 116, the seventh rigid sub-region 117, and the eighth rigid sub-region 118 of the first rigid region 110. They are the fifth rigidity, the sixth rigidity, the seventh rigidity and the eighth rigidity, respectively, see FIG. 12. In this embodiment, the first rigid area 110 is divided into four sub-areas by arranging cross-shaped ribs 112 on the film structure 10, and grooves 111 of different structures are provided in the four sub-areas to make them rigid. They are the fifth rigidity, sixth rigidity, seventh rigidity, and eighth rigidity. The structure of the groove 111 can be a geometric shape such as a semicircle, a triangle, a rectangle, or other irregular shapes. In other embodiments, it is also possible to arrange protrusions of different shapes or different densities in the four sub-regions to make them different in rigidity. When the MEMS device is used to detect changes in physical quantities, since the rigidities of the four sub-regions are not the same, their detection capabilities are also different. The number of sub-regions in the first rigid region 110 is not limited to that in this embodiment.

Compared with the method of depositing multiple layers during the preparation of the thin film structure 10 in the MEMS device and etching it to make the thin film structure 10 multi-rigid, in the above MEMS device, the rib 112 is provided in the first rigid region 110. Dividing it into multiple sub-regions with different rigidities or partly the same rigidity can avoid process errors and increased costs caused by multilayer structures and etching processes.

In this embodiment, the protrusion 122 of the second rigid area 120 extends from the surface of the film structure 10 to the support structure 20, see FIG. 4. The protrusion 122 of the second rigid area 120 further extends to the inside of the support structure 20, and plays a role of strengthening and fixing the film structure 10.

In an embodiment, the rib 112 of the first rigid area 110 extends to the second rigid area 120 and the supporting structure 20. Referring to FIG. 11, the ribs 112 around the third rigid sub-region 113 extend to the support structure 20 for supporting the film structure 10 under the second rigid region 120. Referring to FIG. 12, the cross-shaped rib 112 that divides the first rigid region 110 into four sub-regions extends below the second rigid region 120 to support the support structure 20 for supporting the film structure 10. In this embodiment, a part of the ribs 112 of the first rigid region 110 extends to the inside of the support structure 20 to further strengthen and fix the membrane structure 10.

In an embodiment, the support structure 20 includes a substrate 210 and a sacrificial layer 220 formed on the substrate 210. A part of the thin film structure 10 is located on the sacrificial layer 220, that is, the sacrificial layer 220 is between the substrate 210 and the thin film structure 10. When the substrate 210 is reamed, the thin film structure 10 can be prevented from being damaged and affecting the performance of the MEMS device. The sacrificial layer 220 and the substrate 210 are correspondingly provided with a back hole for exposing the first rigid region 110. The second rigid area 120 may be partially exposed in the back hole, or just not exposed at the edge of the back hole. That is, the MEMS device in the above-mentioned embodiment increases the process margin of back hole etching and double-sided yellow light by arranging bumps 122 in the second rigid area 120 and matching the design of the pre-reamed mask, which allows the back hole to be formed Even if the reaming error occurs when the reaming is too large, the reaming position is offset, and the reaming is too large and the reaming position is shifted, the rigidity of the first rigid region 110 is still relatively stable to avoid affecting the performance of the MEMS device.

An embodiment of the present application also provides an electronic device, including an electronic device body and the aforementioned MEMS device provided on the electronic device body. The electronic equipment can be mobile phones, digital cameras, notebook computers, personal digital assistants, MP3 players, hearing aids, televisions, telephones, conference systems, wired headsets, wireless headsets, voice recorders, recording equipment, line controllers, and so on.

The present application also provides a method for manufacturing a MEMS device. Referring to FIG. 13, the method includes the following steps:

In step S100, a substrate is provided.

As shown in FIG. 14, a substrate 210 is provided. The substrate 210 in this embodiment serves as the supporting structure 20 or a part of the supporting structure 20 supporting the thin film structure 10. In step S100, cleaning and drying of the substrate 210 may also be included. The substrate 210 may be a silicon substrate. Silicon has the characteristics of high strength, good wear resistance, etc., can well support the thin film structure 10 on it, and is not easy to wear, so that the manufactured MEMS device has a longer life.

In step S200, a trench is formed on the substrate.

As shown in FIG. 15, the trench 212 may be formed in an area corresponding to the second rigid area 120 of the thin film structure 10 on the substrate 210. From the top view, the grooves 212 (full text inspection) on both sides of the substrate 210 may be an integral structure or an independent structure. The depth of each trench 212 in the substrate 210 may be the same or different. In this embodiment, the aspect ratios of the trenches 212 are the same, so that the manufacturing process of step S200 is simpler, and only the trenches 212 in the substrate 210 are simultaneously etched. Optionally, the aspect ratio of the trench 212 in the substrate 210 is 3:1. In other embodiments, trenches 212 with different aspect ratios may also be formed in the substrate 210.

In step S300, a sacrificial layer is formed on the substrate.

As shown in FIG. 16, the sacrificial layer 220 is located on the substrate 210 and backfills a part of the trench 212 in the substrate 210. The sacrificial layer 220 may be a dielectric oxide layer, such as silicon dioxide. In this embodiment, the substrate 210 and the sacrificial layer 220 together serve as the supporting structure 20 supporting the thin film structure 10.

Step S400, providing a thin film structure.

As shown in FIG. 17, the film structure 10 includes a first rigid area 110 having a first rigidity in the middle area and a second rigid area 120 having a second rigidity in the edge area. The first rigidity is less than the second rigidity. The second rigid area 120 includes at least one protrusion 122 formed in the groove 212. In this embodiment, the specific steps of step S400 include a single deposition of semiconductor material and backfilling the trench 212 in the substrate 210 to form the thin film structure 10. The semiconductor material can be a deposition material in a semiconductor process such as single crystal silicon, silicon nitride, polysilicon, silicon carbide, and diamond. After the trench 212 is backfilled with semiconductor material, the protrusion 122 of the second rigid region 120 is formed. In this embodiment, only a single deposition of the semiconductor material is required to form the thin film structure 10 and the protrusions 122 thereon, and the manufacturing process is simple.

In step S500, the substrate is etched to form a back hole at least partially corresponding to the first rigid region.

As shown in FIG. 18, the substrate 210 is etched to form a back hole at least partially corresponding to the first rigid region 110 of the thin film structure 10. In the traditional method of manufacturing MEMS devices, when the substrate 210 is etched to form the back hole, that is, the hole is reamed, the rigidity of the first rigid region 110 of the thin film structure 10 is determined by the boundary of the etched back hole, but due to the hole reaming error, Often, the rigidity of the first rigid region 110 is substantially changed, thereby affecting the performance of the MEMS device. Optionally, the substrate 210 is etched using a deep ion reactive etching (DRIE, Deep Reactive Ion Etching) process.

In step S600, the area corresponding to the sacrificial layer and the back hole is removed to expose the first rigid area.

As shown in FIG. 19, the membrane structure 10 is partially located on the supporting structure 20. The area corresponding to the sacrificial layer 220 and the back hole is removed, so that the support structure 20 is provided with a back hole for exposing the first rigid area 110. The support structure 20 is used to support the membrane structure 10, and the membrane structure 10 The first rigid area 110 deforms upward or downward, thereby generating a variable capacitance between the first rigid area 110 and the back plate. By measuring the magnitude of the changed capacitance, the magnitude of the physical quantity that causes the first rigid region 110 to deform, such as air sound waves, mechanical vibration, etc., can be known. Among them, pressure such as air acoustic waves or mechanical vibration can come from the gap between the membrane structure 10 and the back plate, which causes the membrane structure 10 to deform toward the side where the support structure 20 is located; the pressure can also come from the side where the support structure 20 is located, so that The film structure 10 deforms toward the side where the back plate is located. When the thin film structure 10 deforms toward the side where the support structure 20 is located, the distance between the first rigid area 110 and the back plate becomes larger; when the thin film structure 10 deforms toward the side where the back plate is located, the first rigid area 110 The distance between the backplane and the backplane becomes smaller.

In one embodiment, when removing the area of the sacrificial layer 220 opposite to the back hole in the above step S600, a wet etching process may be used, such as using a hydrofluoric acid (HF) solution on the part of the sacrificial layer 220 opposite to the back hole To remove. The HF solution has the property of corroding silicon dioxide. The portion of the sacrificial layer 220 between the thin film structure 10 and the substrate 210 opposite to the back hole can be removed by the HF solution, so that the thin film structure 10 and the substrate 210 can be separated.

In the above-mentioned method of manufacturing the MEMS device, the trench 212 is formed on the substrate 210, so that the second rigid region 120 at the edge area of the thin film structure 10 forms at least one protrusion 122 in the trench 212, thereby increasing the manufacturing process when the substrate 210 is expanded. When the reaming is too large, the reaming position is shifted, and the reaming is too large and the position is shifted, the rigidity of the first rigid region 110 of the film structure 10 can still be relatively stable, and the reaming error will not cause the second The rigidity of a rigid area 110 changes substantially, which affects the performance of the MEMS device during use. Moreover, the thin film structure 10 and the protrusions 122 included in the second rigid region 120 can be manufactured by the same deposition process, and the manufacturing process is simple.

In another embodiment, referring to FIGS. 11 and 12, the first rigid region 110 includes at least one rib 112 formed in the groove 212 to divide the first rigid region 110 into a plurality of sub-regions, and the rigidity of each sub-region is Less than the second rigidity. As shown in FIG. 20, a trench 212 is also formed in the area corresponding to the first rigid area 110 of the thin film structure 10 and the substrate 210. When a semiconductor material is deposited on the sacrificial layer 220, the first rigid area of the thin film structure 10 is also backfilled. The groove 212 in the region corresponding to 110 forms the rib 112 of the first rigid region 110. The ribs 112 formed in the first rigid area 110 divide it into a plurality of sub-areas. The rigidity of these sub-regions can be the same or different. The protrusion 122 formed by the second rigid area 120 may also be a rib structure.

In this embodiment, the above step S400 further includes forming a groove 111 with a different structure in each sub-region in the first rigid region 110 of the thin film structure 10 so that the rigidity of each sub-region is different, see FIG. 12. The grooves 111 in each sub-region can be formed on the same surface of the thin film structure 10 or on different surfaces. The depth of the groove 111 in each sub-region can be the same or different, and the width can be the same or different. In this embodiment, the groove 111 of each sub-region and the rib 112 in the first rigid region 110 form a closed geometric structure. In other embodiments, it is also possible to form protrusions with different structures in each sub-region in the first rigid region 110 of the thin film structure 10 to make the rigidity of each sub-region different.

The rigidity of the different sub-regions of the thin film structure 10 in the MEMS device is generally determined by the thickness of the thin film structure 10 of each sub-region. In the MEMS device, the deposition process is used to control the rigidity of the different sub-regions when the thin film structure 10 is formed, or the The etching technique reduces the thickness of the sub-regions of the thin film structure 10 to control the rigidity of different sub-regions, and the etching technique is time-controlled. In the above-mentioned method for preparing a MEMS device, a trench 212 is formed in a position where the substrate 210 is opposite to the first rigid region 110, and the trench 212 is backfilled with a semiconductor material to form the multiple rigidity of the first rigid region 110. The deposition process of the semiconductor material only needs a single time. Compared with the traditional method, the precision is higher, and the yellow light and etching process are reduced, and the process flow is simpler. In addition, the ribs 112 of the first rigid area 110 and the protrusions 122 of the second rigid area 120 of the thin film structure 10 can be made at the same time by etching the groove 212 in the corresponding area of the substrate 210 and backfilling the groove 212, which improves The manufacturing margin during the etching of the substrate 210 divides the first rigid region 110 of the thin film structure 10 into a plurality of sub-regions with the same rigidity or different rigidities.

In the foregoing embodiment, the MEMS device is used as an example of a microphone, and the thin film structure 10 is a diaphragm or a back plate in the microphone. In other embodiments, the MEMS device may also be an accelerometer. The accelerometer includes a thin film structure 10. The ribs 112 divide the thin film structure 10 into multiple sub-regions with multiple rigidities. For example, some of the sub-regions are masses. Some sub-regions are spring structures, and the protrusions 122 or ribs 112 provided in the thin film structure 10 can enhance the rigidity and weight of the mass; the MEMS device can also be a scanning mirror, which includes the thin film structure 10. The convex rib 112 divides the scanning mirror into multiple sub-regions with multiple rigidities, for example, some of the sub-regions are mirrors, and some of the sub-regions are spring structures, and the projections 122 or ribs 112 are provided in the thin film structure 10 It can slow down the deformation of the mask.

It can be understood that the dimensions of all the drawings in this case do not represent actual ratios, and are merely schematic diagrams.

The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, All should be considered as the scope of this specification.

The above-mentioned embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can be made, and these all fall within the protection scope of this application. Therefore, the scope of protection of the patent of this application shall be subject to the appended claims.

Claims

A MEMS device, characterized in that it comprises:

The film structure includes a first rigid area with a first rigidity in the middle area and a second rigid area with a second rigidity in the edge area, the first rigidity is less than the second rigidity, the second rigid area It includes at least one protrusion extending outward from the surface of the film structure.
The MEMS device according to claim 1, wherein the protrusion is a rib-shaped or column-shaped structure.
The MEMS device according to claim 1, wherein the first rigid region includes a plurality of sub-regions, and the rigidity of each sub-region is less than the second rigidity.
3. The MEMS device according to claim 3, wherein the first rigid area comprises a rib extending outward from the surface of the thin film structure to divide the first rigid area into the plurality of sub-areas.
The MEMS device according to claim 3, wherein at least two sub-areas of the plurality of sub-areas have the same rigidity.
The MEMS device according to claim 3, wherein each of the plurality of sub-regions has a different rigidity.
The MEMS device according to claim 6, wherein the plurality of sub-regions are provided with grooves of different structures or protrusions of different structures.
The MEMS device according to claim 1, further comprising a support structure, the thin film structure is partially located on the support structure, and the support structure is provided with a back hole for exposing the first rigid area.
8. The MEMS device according to claim 8, wherein the protrusion extends from the surface of the thin film structure to the supporting structure, and the supporting structure has a groove for accommodating the protrusion.
The MEMS device according to claim 8, wherein the first rigid area comprises a rib extending outward from the surface of the thin film structure to divide the first rigid area into the plurality of sub-areas, so The ribs extend from the first rigid area of the film structure to the second rigid area of the film structure and the support structure.
The MEMS device of claim 8, wherein the supporting structure comprises:

Substrate, and

A sacrificial layer formed on the substrate; the thin film structure is partially located on the sacrificial layer.
An electronic device, comprising an electronic device body, which is characterized in that it further comprises the MEMS device according to any one of claims 1 to 11 arranged on the electronic device body.
A method for preparing MEMS equipment, characterized in that it comprises:

Provide substrate;

Forming a groove on the substrate;

A film structure is provided. The film structure includes a first rigid area with a first rigidity in the middle area and a second rigid area with a second rigidity in the edge area, the first rigidity is less than the second rigidity, so The second rigid area includes at least one protrusion formed in the groove.
The method of claim 13, wherein the first rigid area of the thin film structure includes at least one rib formed in the groove to divide the first rigid area into a plurality of sub-areas, each The rigidity of each sub-region is less than the second rigidity.
The method according to claim 13 or 14, wherein the step of providing the thin film structure comprises:

The semiconductor material is deposited in a single pass and the trench is backfilled to form the thin film structure.
The method according to claim 14, wherein the step of providing a thin film structure further comprises:

In the first rigid area of the thin film structure, each sub-area is formed with a groove of a different structure or a protrusion of a different structure to make the rigidity of each sub-area different.
The method according to claim 13, further comprising:

Before the step of providing the thin film structure, a sacrificial layer is formed on the substrate, and the sacrificial layer is located between the substrate and the thin film structure.
17. The method of claim 17, wherein the sacrificial layer is silicon dioxide.
The method according to claim 17, further comprising:

Etching the substrate to form a back hole at least partially corresponding to the first rigid region of the thin film structure; and

The area corresponding to the sacrificial layer and the back hole is removed to expose the first rigid area of the thin film structure.
18. The method according to claim 19, wherein in the step of removing the area corresponding to the sacrificial layer and the back hole to expose the first rigid area of the thin film structure, a wet etching process is used to The sacrificial layer is removed.