WO2023109614A1

WO2023109614A1 - Mems structure and manufacturing method therefor

Info

Publication number: WO2023109614A1
Application number: PCT/CN2022/137253
Authority: WO
Inventors: 胡永刚; 冷华星; 周伍清; 蔡华洁
Original assignee: 无锡华润上华科技有限公司
Priority date: 2021-12-15
Filing date: 2022-12-07
Publication date: 2023-06-22
Also published as: CN116264659A

Abstract

The present invention relates to an MEMS structure and a manufacturing method therefor. The manufacturing method for an MEMS structure comprises: acquiring a substrate; forming, on the substrate, a sacrificial layer having a plurality of hollowed tunnels; forming a structural layer on the sacrificial layer; patterning the structural layer to form a required structure, which involves respectively forming, right above the hollowed tunnels, corrosion holes corresponding to the hollowed tunnels; and corroding the sacrificial layer by means of the corrosion holes, so as to form a cavity. In the present invention, the plurality of hollowed tunnels are arranged in the sacrificial layer, such that a corrosive agent can enter the tunnels during the corrosion of the sacrificial layer, so as to increase the corrosion rate. Moreover, since the corrosive agent can be diffused in the whole lengthwise direction of a tunnel after entering the tunnel from any position, a sacrificial layer in a predetermined corrosion area can be completely corroded simply by means of providing a small number of corrosion holes, thereby preventing the strength of the structural layer from being affected by the intensive provision of corrosion holes.

Description

MEMS structure and its manufacturing method

technical field

The invention relates to the technical field of semiconductor devices, in particular to a MEMS structure and a method for manufacturing the MEMS structure.

Background technique

Micro-Electro-Mechanical System (MEMS) devices are usually produced using integrated circuit manufacturing techniques. Suspension structures are common in MEMS structures. For example, in the manufacturing process of MEMS microphones, processes (such as film deposition, corrosion, etc.) are generally only performed on one side of the semiconductor substrate, while processes are not performed on the other side. To form a cavity between the MEMS microphone back plate and the diaphragm, usually a thick layer of silicon oxide is formed on the diaphragm or the back plate as a sacrificial layer, with an exemplary thickness of 3-5 microns, and then on the sacrificial layer The backplane or diaphragm is formed, and finally the sacrificial layer is etched away to form a cavity.

In an exemplary manufacturing process, the etching of the sacrificial layer is mainly that the gas or liquid that corrodes the sacrificial layer passes through the etching hole to etch away the sacrificial layer under the structural layer to form a suspended structure, as shown in FIG. 1 and FIG. 2 . 1 is a schematic cross-sectional view of the MEMS structure when the sacrificial layer is not completely etched, and FIG. 2 is a schematic cross-sectional view of the MEMS structure after the sacrificial layer is etched. In an exemplary manufacturing process, the structural layer must be provided with relatively dense or sufficiently large corrosion holes to obtain a sufficient corrosion rate and completely corrode the sacrificial layer in the predetermined corrosion area, but dense/large-area corrosion holes are easy to have an effect on the strength or function of the structural layer.

Contents of the invention

Based on this, it is necessary to provide a method for manufacturing a MEMS structure that can shorten the etching time of the sacrificial layer.

A method for manufacturing a MEMS structure, comprising: obtaining a substrate; forming a sacrificial layer with a plurality of hollow tunnels on the substrate; forming a structural layer on the sacrificial layer; patterning the structural layer to form a desired structure, The method includes forming corrosion holes corresponding to the hollow tunnels directly above the hollow tunnels; corroding the sacrificial layer through the corrosion holes to form cavities.

In the manufacturing method of the above MEMS structure, a plurality of hollow tunnels are arranged in the sacrificial layer, so that the etchant can enter the tunnels when the sacrificial layer is corroded, thereby accelerating the corrosion rate. And because the etchant can diffuse in the entire length direction of the tunnel after entering the tunnel at any position, only a small number of corrosion holes can completely corrode the sacrificial layer in the predetermined corrosion area, avoiding the influence of dense corrosion holes on the structure layer strength.

In one of the embodiments, the step of forming a sacrificial layer with multiple hollow tunnels on the substrate includes: forming multiple grooves on the substrate; depositing and forming a sacrificial layer on the substrate, sacrificial The layer material seals each of the grooves, and each of the grooves forms the hollow tunnel due to incomplete filling of the sacrificial layer material.

In one of the embodiments, in the step of forming a sacrificial layer having a plurality of hollow tunnels on the substrate, the air pressure in the formed hollow tunnels is lower than normal pressure.

In one of the embodiments, in the step of depositing and forming a sacrificial layer on the substrate, the pressure of the reaction chamber of the deposition machine is lower than normal pressure during deposition.

In one of the embodiments, in the step of forming a plurality of grooves on the substrate, the area of the bottom of the same groove is larger than the area of the opening of the groove.

In one of the embodiments, the step of forming a plurality of grooves on the substrate includes: forming a first sacrificial layer on the substrate; patterning the first sacrificial layer, forming the plurality of grooves; the step of depositing and forming a sacrificial layer on the substrate includes depositing and forming a second sacrificial layer on the first sacrificial layer; The step of forming the sacrificial layer includes etching the first sacrificial layer and the second sacrificial layer.

In one embodiment, the step of forming a plurality of grooves on the substrate includes: patterning the substrate to form a plurality of grooves.

In one of the embodiments, the step of forming a plurality of grooves on the substrate includes: forming a groove material layer on the substrate; patterning the groove material layer, and forming a groove material layer on the groove material layer Form the plurality of grooves.

In one of the embodiments, the step of forming corrosion holes corresponding to each hollow tunnel directly above each hollow tunnel includes: forming two corrosion holes above each groove, one located in a concave One end of the groove and the other at the other end of the groove.

In one embodiment, in the step of forming a plurality of grooves on the substrate, the formed grooves include at least one shaped groove.

In one of the embodiments, the MEMS structure manufacturing method is used to manufacture capacitive MEMS microphones.

It is also necessary to provide a MEMS structure.

A MEMS structure includes a base and a structure layer, a cavity is formed between the base and the structure layer, and a plurality of grooves are formed at the bottom of the cavity.

In one of the embodiments, the cavity is formed by etching a sacrificial layer.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the traditional technology. Obviously, the accompanying drawings in the following description are only the present invention For some embodiments of the application, those skilled in the art can also obtain other drawings based on these drawings without creative work.

1 is a schematic cross-sectional view of a MEMS structure when the sacrificial layer is not completely etched in an exemplary sacrificial layer etching process in the prior art;

2 is a schematic cross-sectional view of the MEMS structure after the sacrificial layer is etched in an exemplary sacrificial layer etching process in the prior art;

Fig. 3 is the flowchart of the manufacturing method of MEMS structure in an embodiment of the present application;

Figure 4a is a schematic diagram of the MEMS structure after step S340 is completed in an embodiment of the present application, wherein the upper part of Figure 4a is a top view of the MEMS structure, and the lower part is a cross-sectional view of the MEMS structure, and Figure 4b is the structure shown in Figure 4a in step S350 The schematic diagram after completion;

Figure 5a is a schematic diagram of the MEMS structure after step S340 is completed in another embodiment of the present application, wherein the upper part of Figure 5a is a top view of the MEMS structure, and the lower part is a cross-sectional view of the MEMS structure, and Figure 5b is the structure shown in Figure 5a in step Schematic diagram of the completed S350;

Figure 6a is a schematic diagram of the MEMS structure after step S340 is completed in another embodiment of the present application, wherein the upper part of Figure 6a is a top view of the MEMS structure, and the lower part is a cross-sectional view of the MEMS structure, and Figure 6b is the structure shown in Figure 6a in step Schematic diagram of the completed S350;

Fig. 7 is a schematic structural diagram of a special-shaped groove in an embodiment of the present application;

Fig. 8 is a schematic diagram of setting a special-shaped groove in an embodiment of the present application so as to release a large area of sacrificial layer through a small number of corrosion holes;

Fig. 9 is a schematic diagram of continuous and discontinuous hollow tunnels.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the associated drawings. A preferred embodiment of the invention is shown in the drawings. However, the present invention can be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be thorough and complete.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood that when an element or layer is referred to as being "on," "adjacent," "connected to" or "coupled to" another element or layer, it can be directly on the other element or layer. A layer may be on, adjacent to, connected to, or coupled to other elements or layers, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers present. layer. It will be understood that, although the terms first, second, third etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

Spatial terms such as "below", "below", "below", "under", "on", "above", etc., in This may be used for convenience of description to describe the relationship of one element or feature to other elements or features shown in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or features described as "below" or "beneath" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "below" and "beneath" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the/the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should also be understood that the terms "consists of" and/or "comprising", when used in this specification, identify the presence of stated features, integers, steps, operations, elements and/or parts, but do not exclude one or more other Presence or addition of features, integers, steps, operations, elements, parts and/or groups. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

Embodiments of the invention are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the invention. As such, variations from the shapes shown are to be expected due to, for example, manufacturing techniques and/or tolerances. Thus, embodiments of the invention should not be limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an implanted region illustrated as a rectangle will, typically, have rounded or curved features and/or a gradient of implant concentration at its edges rather than a binary change from implanted to non-implanted region. Likewise, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation was performed. Thus, the regions shown in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the invention.

In an exemplary sacrificial layer process, the etching of the sacrificial layer is mainly by allowing an etchant (gas or liquid) to pass through the etching hole to etch away the sacrificial layer under the structural material to form a suspended structure. Since the corrosion gas or liquid needs to pass through the corrosion holes to corrode the sacrificial layer under the structural material, this sacrificial layer process has the following disadvantages: 1. The distance between the corrosion holes should not be too large, otherwise the corrosion time will be very long, affecting production efficiency; 2. The structural layer must have a sufficient number of corrosion holes, otherwise the sacrificial layer under the structural material cannot be corroded cleanly, but the dense corrosion holes will affect the strength or function of the material structure; 3. The corrosion boundary is formed by the corrosion holes It is formed naturally after the sacrificial layer is corroded by corrosive gas or liquid, which cannot be controlled; 4. MEMS devices with different structures and uses have different requirements for the shape of the cavity, and some MEMS devices have special requirements for the shape of the cavity. However, in the exemplary sacrificial layer process, due to the arrangement of the etching holes and the etching speed, it is impossible to form a cavity with a special shape and a special boundary.

The manufacturing method of the MEMS structure proposed by the application has the following advantages: 1. It can shorten the corrosion time of the sacrificial layer and improve production efficiency; 2. It can reduce the number of corrosion holes, enhance the strength of the structural layer, and manufacture structures that cannot be manufactured by traditional processing techniques ;3. The corrosion boundary can break through the limitation of the corrosion hole, and form a corrosion boundary on demand.

Fig. 3 is the flowchart of the manufacturing method of MEMS structure in an embodiment, comprises the following steps:

S310, acquiring a base.

In one embodiment of the present application, the base includes a substrate, and the material of the substrate may be Si. In other embodiments, the material of the substrate may also be other semiconductors or semiconductor compounds, such as one of Ge, SiGe, SiC, SiO ₂ or Si ₃ N ₄ . Part of the film layer of the MEMS structure can be formed on the substrate, such as the back plate or diaphragm of the capacitive MEMS microphone.

S320, forming a sacrificial layer having a plurality of hollow tunnels on the substrate.

In one embodiment of the present application, the hollow tunnel is formed by the following method:

A plurality of grooves are formed on the substrate. Grooves can be formed by patterning the substrate, for example, coating a photoresist on the substrate, developing the photoresist after exposure using a sacrificial layer groove photolithography plate to obtain an etching window, and then etching the substrate through the etching window to form groove.

A sacrificial layer is deposited on the substrate, and the material of the sacrificial layer seals each groove, and the groove forms a hollow tunnel due to incomplete filling of the material of the sacrificial layer. In the same groove, the hollow tunnel can be continuous or discontinuous, see Figure 9. For the embodiment in which the hollow tunnel is continuous, the length of the hollow tunnel is the same or similar to the length of the corresponding groove. The continuous type hollow tunnel can obtain a faster sacrificial layer corrosion rate than the discontinuous type.

S330, forming a structural layer on the sacrificial layer.

The material of the structural layer needs to be different from that of the sacrificial layer to ensure that the structural layer is not easily corroded in the subsequent etching step of the sacrificial layer, that is, the sacrificial layer and the structural layer must have a large corrosion selection ratio during etching. Similarly, when the sacrificial layer is corroded, the substrate surface should not be easily corroded, and the sacrificial layer and the substrate surface should also have a large corrosion selectivity ratio.

S340, patterning the structural layer to form corrosion holes and other required structures.

In one embodiment of the present application, the photoresist is coated on the structural layer, and the photoresist is developed after exposure using the corresponding photolithography plate to obtain an etching window, and then the structural layer is etched through the etching window to form Desired structure including corrosion holes.

S350, corroding the sacrificial layer through each corrosion hole to form a cavity.

Before step S350 , other required MEMS structures may also be formed on the structure layer and/or at other positions. For example, for a capacitive MEMS microphone, the sacrificial layer may be etched and released after the pad is formed. After the step S350 is completed, the sacrificial layer at the predetermined position including the hollow tunnel is completely removed.

For the embodiment in which the hollow tunnel is discontinuous, the distance between the boundaries of two adjacent hollow tunnels in the same groove cannot be greater than twice the lateral corrosion ability of the sacrificial layer, that is, the distance from the boundary of the corrosion hole to the corrosion Twice the lateral distance of the border.

The traditional sacrificial layer etching process needs to consider the spacing of the etching holes. It is best to equidistant between the etching holes. The etching time is determined by the maximum spacing between the etching holes, so as to ensure that the sacrificial layer is completely etched in the predetermined area. However, the corrosion holes in the present application do not need to consider the distance between the corrosion holes in the extending direction of the tunnel. During the corrosion process, after the sacrificial layer above the hollow tunnel is corroded, the etchant enters the tunnel and diffuses in the entire length direction of the tunnel (ie, the tunnel extension direction), thereby accelerating the corrosion process. For example, when it is necessary to form a large-area suspended structure, it is only necessary to form several hollow tunnels at equal intervals under the suspended structure, and then set corrosion holes at both ends of each tunnel, even if the distance between the corrosion holes is large, after Reasonable design can also complete the corrosion. The suspended structure formed by this method requires fewer corrosion holes and stronger structural strength. It also has a relatively wide application prospect in some suspended structures that are inconvenient to open corrosion holes.

In an embodiment of the present application, the air pressure in the hollow tunnel formed in step S320 is lower than normal pressure, that is, lower than a standard atmospheric pressure. In this way, after the sacrificial layer above the hollow tunnel is etched away in step S350 , due to the pressure difference, the etchant will be drawn into the hollow tunnel, so that the diffusion speed of the etchant in the hollow tunnel can be accelerated, and the corrosion rate can be increased.

Fig. 4a is a schematic diagram of the MEMS structure after step S340 is completed in an embodiment, wherein the upper part of Fig. 4a is a top view of the MEMS structure, and the lower part is a cross-sectional view of the MEMS structure, and the cross-section does not pass through the etching hole 431; A schematic diagram of the structure shown after step S350 is completed. In this embodiment, step S320 includes:

S321, forming a first sacrificial layer on the substrate.

A first sacrificial layer 422 is deposited on the substrate 410 .

S323, patterning the first sacrificial layer to form a plurality of grooves in the first sacrificial layer.

Coat photoresist on the first sacrificial layer 422, use the sacrificial layer groove photolithography plate to expose and develop the photoresist to obtain an etching window, and then etch the first sacrificial layer 422 through the etching window to form a concave hole. Groove 411.

S325, depositing and forming a second sacrificial layer on the first sacrificial layer.

The material of the second sacrificial layer 424 seals the groove 411 during deposition, and the groove 411 forms a hollow tunnel 421 due to incomplete filling of the material of the second sacrificial layer 424 . Deposition can be easily sealed by adjusting the deposition menu parameters of the machine.

In one embodiment of the present application, the deposition in step S325 adopts a deposition process lower than normal pressure, that is, the pressure of the reaction chamber (chamber) of the deposition machine is lower than normal pressure during deposition, and the hollow tunnel formed in this way The air pressure in 421 will be lower than normal pressure.

In one embodiment of the present application, when the second sacrificial layer 424 is deposited and sealed, the cavity in the groove 411 (that is, the hollow tunnel 421) is large enough, so the groove 411 is set to a shape whose bottom area is larger than the opening area . In the embodiment shown in Fig. 4a and Fig. 4b, the cross section of the groove 411 is trapezoidal. In other embodiments, the groove 411 may also have other shapes, such as a rectangular groove in section. The dotted rectangle in Fig. 4a represents the position of the groove 411 (the opening profile of the groove 411), and two corrosion holes 431 penetrating the structural layer 430 are respectively formed above each groove 411, and one corrosion hole 431 is located at one end of the groove 411 , and the other is located at the other end of the groove 411 .

In one embodiment of the present application, step S350 is to release both the first sacrificial layer 422 and the second sacrificial layer 424, and the etching boundary 433 is shown in FIG. The material can be the same.

Figure 5a is a schematic diagram of the MEMS structure after step S340 in another embodiment, wherein the upper part of Figure 5a is a top view of the MEMS structure, and the lower part is a cross-sectional view of the MEMS structure, and the section does not pass through the corrosion hole 531; Figure 5b is Figure 5a The structure shown is a schematic diagram after step S350 is completed.

In the embodiment shown in FIG. 5 a , the groove 511 is directly opened on the upper surface of the substrate 510 . In step S320, after patterning the substrate 510 to form the groove 511, a sacrificial layer 522 is deposited on the substrate, and the material of the sacrificial layer seals the groove 511 during deposition, and the groove 511 forms a hollow tunnel 521 due to incomplete filling of the material of the sacrificial layer . Deposition can be easily sealed by adjusting the deposition menu parameters of the machine.

In one embodiment of the present application, step S320 deposits the sacrificial layer 522 using a deposition process below normal pressure, that is, the pressure of the reaction chamber of the deposition machine is lower than normal pressure during deposition, and the hollow tunnel formed in this way The air pressure in 521 will be lower than normal pressure.

In one embodiment of the present application, in order to make the sacrificial layer 522 deposited and sealed, the cavity in the groove 511 (that is, the hollow tunnel 521 ) is large enough, so the groove 511 is set in a shape whose bottom area is larger than the opening area. In the embodiment shown in Fig. 5a and Fig. 5b, the cross section of the groove 511 is trapezoidal. In other embodiments, the groove 511 may also have other shapes, such as a rectangular groove in section. The dotted rectangle in Figure 5a represents the position of the groove 511 (the opening profile of the groove 511), and two corrosion holes 531 penetrating the structural layer 530 are respectively formed above each groove 511, and one corrosion hole 531 is located at one end of the groove 511 , and the other is located at the other end of the groove 511 . After the sacrificial layer 522 is released in step S350, the substrate 510 surrounding the groove 511 is etched slightly, and the etched boundary 533 is as shown in FIG. 5b.

Fig. 6a is a schematic diagram of the MEMS structure after step S340 is completed in another embodiment, wherein the upper part of Fig. 6a is a top view of the MEMS structure, and the lower part is a cross-sectional view of the MEMS structure, and the cross-section does not pass through the corrosion hole 631; Fig. 6b is Fig. 6a The structure shown is a schematic diagram after step S350 is completed. In this embodiment, step S320 includes:

S322, forming a groove material layer on the substrate.

A groove material layer 620 is deposited on the substrate 610 . The material of the groove material layer 620 is different from that of the substrate 610 and the sacrificial layer 622 .

S324, pattern the groove material layer, and form a plurality of grooves in the groove material layer.

Coat photoresist on the groove material layer 620, use the sacrificial layer groove photolithographic plate to expose and develop the photoresist to obtain an etching window, and then etch the groove material layer 620 through the etching window to form a concave hole. Groove 611.

After the groove 611 is formed, a sacrificial layer 622 is deposited on the groove material layer 620 , the material of the sacrificial layer seals the groove 611 during deposition, and the groove 611 forms a hollow tunnel 621 due to incomplete filling of the material of the sacrificial layer. Deposition can be easily sealed by adjusting the deposition menu parameters of the machine.

In one embodiment of the present application, step S320 deposits the sacrificial layer 622 using a deposition process below normal pressure, that is, the pressure of the reaction chamber of the deposition machine is lower than normal pressure during deposition, and the hollow tunnel formed in this way The air pressure in 621 will be lower than normal pressure.

In one embodiment of the present application, in order to deposit and seal the sacrificial layer 622 , the cavity in the groove 611 (that is, the hollow tunnel 621 ) is large enough, so the groove 611 is set in a shape whose bottom area is larger than the opening area. In the embodiment shown in Fig. 6a and Fig. 6b, the cross section of the groove 611 is trapezoidal. In other embodiments, the groove 611 may also have other shapes, such as a rectangular groove in section. The dotted rectangle in Figure 5a represents the position of the groove 611 (the opening profile of the groove 611), and two corrosion holes 631 penetrating the structural layer 630 are respectively formed above each groove 611, and one corrosion hole 631 is located at one end of the groove 611 , and the other is located at the other end of the groove 611. When the sacrificial layer 622 is etched in step S350 , the groove material layer 620 should not be easily corroded, so the sacrificial layer 622 and the groove material layer 620 also have a large etching selectivity ratio. After the etching is completed, the corrosion boundary 633 is as shown in FIG. 6b.

In one embodiment of the present application, step S320 includes at least one special-shaped groove in each of the grooves formed on the substrate. That is, the grooves can be made into different shapes as required, thereby forming special-shaped tunnels, as shown in FIG. 7 . In the embodiment shown in Figure 7, the special-shaped groove is a broken line; in other embodiments, the special-shaped groove can also be other shapes, such as curved, cross, star, ring, square, etc. is an irregular shape. By setting the special-shaped groove, the required cavity can be obtained with fewer corrosion holes. Referring to FIG. 8 , in this embodiment, the groove is a square frame, and only one etching hole needs to be provided at each of the two opposite corners of the frame to obtain a square cavity. In addition, with the help of special-shaped grooves, the corrosion boundary of the sacrificial layer can break through the limitation of the corrosion hole, and form a corrosion boundary as needed to form a cavity with a special shape with a special boundary, so as to meet the special shape of the cavity for some MEMS devices. demand.

The method for manufacturing the above MEMS structure can be used to manufacture capacitive MEMS microphones, and can also be used to manufacture other MEMS structures with suspended structures.

The present application correspondingly provides a MEMS structure, including a base and a structure layer, a cavity is formed between the base and the structure layer, the cavity is formed by etching a sacrificial layer, and a plurality of grooves are formed at the bottom of the cavity. The specific composition of the MEMS structure can refer to FIG. 5b and FIG. 6b. The MEMS structure can be formed by the manufacturing method of the MEMS structure in the foregoing embodiments.

It should be understood that although the various steps in the flow chart of the present application are displayed in sequence according to the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least some of the steps in the flow chart of the present application may include multiple steps or stages, and these steps or stages are not necessarily executed at the same time, but may be executed at different times, and the steps or stages The execution sequence is not necessarily performed sequentially, but may be performed alternately or alternately with other steps or at least a part of steps or stages in other steps.

In the description of this specification, descriptions referring to the terms "some embodiments", "other embodiments", "ideal embodiments" and the like mean that specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in this specification. In at least one embodiment or example of the invention. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

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

The above-mentioned embodiments only express several implementation modes of the present application, and the description thereof is relatively specific and detailed, but should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of protection of the patent application should be based on the appended claims.

Claims

A method of manufacturing a MEMS structure, comprising:

get base;

forming a sacrificial layer having a plurality of hollow tunnels on the substrate;

forming a structural layer on the sacrificial layer;

Patterning the structural layer to form a required structure includes forming corrosion holes corresponding to each hollow tunnel directly above each hollow tunnel;

The sacrificial layer is etched through each of the etching holes to form a cavity.
The method for manufacturing a MEMS structure according to claim 1, wherein the step of forming a sacrificial layer having a plurality of hollow tunnels on the substrate comprises:

forming a plurality of grooves on the substrate;

A sacrificial layer is formed by depositing on the base, and the material of the sacrificial layer seals each of the grooves, and the hollow tunnel is formed in each of the grooves due to incomplete filling of the material of the sacrificial layer.
The manufacturing method of the MEMS structure according to claim 1, characterized in that, in the step of forming a sacrificial layer having a plurality of hollow tunnels on the substrate, the air pressure in the formed hollow tunnels is lower than normal pressure.
The method for manufacturing a MEMS structure according to claim 2, wherein in the step of depositing and forming a sacrificial layer on the substrate, the gas pressure in the reaction chamber of the deposition machine is lower than normal pressure during deposition.
The method for manufacturing a MEMS structure according to claim 2, wherein in the step of forming a plurality of grooves on the substrate, in the same groove, the area of the bottom of the groove is greater than the area of the opening of the groove .
The method for manufacturing a MEMS structure according to claim 2, wherein the step of forming a plurality of grooves on the substrate comprises:

forming a first sacrificial layer on the substrate;

patterning the first sacrificial layer, forming the plurality of grooves in the first sacrificial layer;

The step of depositing and forming a sacrificial layer on the substrate includes depositing and forming a second sacrificial layer on the first sacrificial layer;

The step of etching the sacrificial layer through each of the etching holes includes etching the first sacrificial layer and the second sacrificial layer.
The method for manufacturing a MEMS structure according to claim 2, wherein the step of forming a plurality of grooves on the substrate comprises: patterning the substrate to form a plurality of grooves.
The method for manufacturing a MEMS structure according to claim 2, wherein the step of forming a plurality of grooves on the substrate comprises:

forming a layer of recessed material on the substrate;

The groove material layer is patterned to form the plurality of grooves in the groove material layer.
The manufacturing method of the MEMS structure according to claim 8, characterized in that, the material of the groove material layer is different from that of the substrate and the sacrificial layer.
The method for manufacturing a MEMS structure according to claim 1, wherein the step of forming corrosion holes corresponding to each hollow tunnel directly above each hollow tunnel comprises: above each groove, each Two etch holes are formed, one at one end of a groove and the other at the other end of the groove.
The manufacturing method of the MEMS structure according to claim 2, characterized in that, in the same groove, the hollow tunnel is continuous or discontinuous.
The method for manufacturing a MEMS structure according to claim 11, wherein the hollow tunnel is continuous, and the length of the hollow tunnel is the same or similar to the length of the corresponding groove.
The method for manufacturing a MEMS structure according to claim 11, wherein the hollow tunnel is discontinuous, and the distance between the boundaries of two adjacent hollow tunnels in the same groove is less than or equal to the boundary of the corrosion hole. Twice the lateral distance to the corrosion boundary.
The method for manufacturing a MEMS structure according to claim 2, wherein the plurality of grooves includes at least one special-shaped groove, and the special-shaped groove is a broken line type, a curved line, a cross shape, a star shape, a ring shape, Box-shaped or irregular graphics.
A MEMS structure includes a base and a structure layer, a cavity is formed between the base and the structure layer, and the feature is that a plurality of grooves are formed at the bottom of the cavity.