Micromechanical structure and manufacturing method

Abstract

The invention discloses a micro-mechanical structure and a manufacturing method. The micro-mechanical structure comprises a substrate; the first sacrificial layer is located on the substrate, and a first cavity is formed in the first sacrificial layer; the first structure layer is located on the first sacrificial layer, and the first structure layer comprises a protruding structure protruding towards the direction of the substrate; wherein the first cavity enables at least part of the first structure layer including the protruding structure to be suspended, and the surface of the side, facing the substrate, of the protruding structure comprises an arc shape, so that the first structure layer is prevented from being adhered to an adjacent structure below the first structure layer. According to the micro-mechanical structure provided by the invention, the convex structure is arranged on the structural layer, so that the first structural layer can be prevented from being adhered to an adjacent structure in a deformation or movement process, the possibility of failure of a device due to adhesion is reduced, and the convex structure has relatively high mechanical strength; the maximum amplitude of the first structure layer can be limited by designing the height of the protruding structure, the reliability and stability of the micromechanical mechanism are improved, and the use scene is expanded.

Description

Technical Field

[0001] The present invention relates to the technical field of microelectronic devices, and more specifically, to a micromechanical structure and a manufacturing method thereof. Background Art

[0002] Micro-Electro-Mechanical System (MEMS) usually includes micro-mechanical structures to achieve specific functions. MEMS usually includes a sacrificial layer and a structural layer. By etching the sacrificial layer (also called release), a release cavity is formed under the structural layer, so that part of the structural layer is suspended to form a movable structure.

[0003] When the movable structure is deformed or moves during the operation of the device, it is easy to adhere to the adjacent structure, causing device failure.

[0004] In order to prevent the movable structure from adhering to the adjacent structure, a bump is usually provided on the movable structure to reduce the contact area between the movable structure and the adjacent structure; however, the top of the bump is still a plane, and there is still a problem of adhesion with the adjacent structure, and the edges and corners of the bump may be bumped and broken, resulting in structural damage; further, the presence of the bump will also affect the mechanical strength of the entire movable structure in this area, causing the entire movable structure to have a weak point in strength in this area, affecting the overall performance of the micromechanical structure.

[0005] Therefore, there is an urgent need to design a micromechanical structure to improve the performance of the movable structure, reduce the risk of adhesion between the structural layer and the adjacent structure, and enhance its structural strength. Summary of the invention

[0006] The purpose of the present invention is to provide a micromechanical structure and a manufacturing method to solve the problems existing in the prior art, such as the adhesion of adjacent structures of products leading to device failure, insufficient strength of the structural layer, and inability to meet specific maximum amplitude requirements. The reliability and stability of the micromechanical mechanism are improved, and the application scenarios are expanded.

[0007] According to one aspect of the present invention, the present invention provides a micromechanical structure, comprising: a substrate; a first sacrificial layer, located on the substrate, a first cavity formed in the first sacrificial layer; a first structural layer, located on the first sacrificial layer, the first structural layer comprising a protruding structure protruding toward the substrate; wherein the first cavity causes at least part of the first structural layer including the protruding structure to be suspended, and the surface of the protruding structure facing the substrate side comprises an arc to prevent the first structural layer from adhering to an adjacent structure thereunder.

[0008] Optionally, a surface of the protruding structure facing the substrate includes an arched curved surface or at least a partial spherical surface.

[0009] Optionally, the protrusion structure includes a first protrusion and a second protrusion, the first protrusion is a column or a table, the second protrusion is located at the bottom of the first protrusion, and a surface of the second protrusion facing the substrate includes an arched curved surface or at least a partial spherical surface.

[0010] Optionally, the first structural layer includes a plurality of stacked sub-structural layers, and the protruding structure consists of at least two sub-structural layers.

[0011] Optionally, the raised structure includes a first substructure layer and a second substructure layer located above the first substructure layer, the longitudinal cross-section of the first substructure layer includes at least one of a bow shape, an arch shape, and an I-shape, and the longitudinal cross-section of the second substructure layer includes at least one of a rectangle shape, a convex shape, and an I-shape corresponding to the first substructure layer.

[0012] Optionally, the protruding structure has a preset height to limit a maximum vibration amplitude of the first structural layer in a protruding direction of the protruding structure.

[0013] Optionally, the protruding structure has a specific weight, and the protruding structure also serves as a counterweight for the first structural layer, and the vibration performance of the first structural layer is adjusted by adjusting the weight of the protruding structure.

[0014] Optionally, the first structural layer includes a plurality of the protruding structures, and the plurality of the protruding structures are located in different regions of the first structural layer to change the mechanical properties, electrical properties and weight of corresponding regions of the first structural layer.

[0015] Optionally, the material of the first sacrificial layer includes at least one of silicon oxide, borosilicate glass, phosphosilicate glass or borophosphosilicate glass.

[0016] Optionally, the first structural layer includes at least one of polycrystalline silicon, single crystal silicon, amorphous silicon, and silicon nitride.

[0017] Optionally, the first cavity is formed by etching the first sacrificial layer through an etching window on the first structural layer, and the etching process of the first sacrificial layer includes at least one of wet etching using a buffered oxide etchant and gas-phase dry etching using hydrofluoric acid.

[0018] Optionally, the etching window and the protruding structure are staggered in the plane where the first structural layer is located.

[0019] Optionally, the micromechanical structure is used in a MEMS chip.

[0020] According to another aspect of the present invention, a method for manufacturing a micromechanical structure is provided, comprising: forming a first sacrificial layer on a substrate; forming a first mask layer on the first sacrificial layer, and forming a first etching window on the first mask layer; etching the first sacrificial layer through the first etching window to form a first pit in the first sacrificial layer; removing the first mask layer; depositing a structural layer material on the surface of the first sacrificial layer to form a first structural layer; forming a second etching window on the first structural layer, etching the first sacrificial layer through the second etching window to form a first cavity in the first sacrificial layer; wherein the first cavity causes the portion of the first structural layer including the protruding structure to be suspended in the air to form a movable first structural layer having a protruding structure.

[0021] Optionally, a bottom plane of the first pit corresponds to a shape of the first etching window, and a side surface of the first pit is arc-shaped.

[0022] Optionally, the first pit is formed by a dry or wet isotropic etching process, and the first pit is used to assist in the formation of a protruding structure.

[0023] Optionally, after removing the first mask layer, depositing a structural layer material on the surface of the first sacrificial layer, and before forming the first structural layer, it also includes: forming a second mask layer, and forming a third etching window on the second mask layer; etching the first sacrificial layer through the second mask layer to form a second pit in the first sacrificial layer; removing the second mask layer; wherein the position of the third etching window corresponds to the first pit, and the size of the third etching window is not less than the size of the first pit; the second pit is formed on the basis of the first pit, and the depth of the second pit is greater than the depth of the first pit.

[0024] Optionally, the protrusion structure includes a first protrusion and a second protrusion, the first protrusion is a column or a table, the second protrusion is located at the bottom of the first protrusion, and a surface of the second protrusion facing the substrate includes an arched curved surface or at least a partial spherical surface.

[0025] The micromechanical structure and manufacturing method provided by the embodiments of the present invention, by arranging an arc-shaped protruding structure on the structural layer, the protruding structure is generally in the shape of a hemispherical arc, has high structural strength, and its top is approximately point-shaped, which can prevent the first structural layer from adhering to the adjacent structure during deformation or movement, thereby avoiding device failure due to adhesion; the arc-shaped protruding structure has high mechanical strength, and the size and radius of the protruding structure can be flexibly adjusted according to needs, which can meet the application scenarios of various structural gaps.

[0026] Furthermore, the protruding structure has a different weight than the planar structure, and the protruding structure can also be used as a counterweight to adjust the vibration performance of the first structural layer; the protruding structure, for example, also has a preset height, and the movable range of the structural layer is limited by the protruding structure, thereby controlling the maximum amplitude of the structural layer. The protruding structure can also include a first protrusion and a second protrusion, which is combined with a columnar or table shape and a hemispherical arc, which can achieve anti-adhesion while ensuring structural strength, and can flexibly adjust the overall length, width and proportion of the protruding structure to meet the needs of various application scenarios.

[0027] The method for manufacturing a micromechanical structure provided in an embodiment of the present invention involves a processing technology that is mature and reliable, simple and easy to implement, and can conveniently obtain a first structural layer with a protruding structure, and then manufacture a corresponding micromechanical structure. This manufacturing method can not only meet a variety of needs, but also has a simple process and high production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings.

[0029] Figure 1 A schematic diagram showing a micromechanical structure of a first embodiment of the present invention is shown;

[0030] Figure 2 A schematic diagram showing the manufacturing process of the micro-mechanical structure according to the first embodiment of the present invention is shown;

[0031] Figure 3-6 Schematic diagram showing various stages in the process of manufacturing the micromechanical structure of the first embodiment of the present invention;

[0032] Figure 7 A schematic diagram showing a micromechanical structure of a second embodiment of the present invention;

[0033] Figure 8 A schematic diagram showing a protruding structure of a micromechanical structure according to a third embodiment of the present invention;

[0034] Fig. 9 A schematic diagram showing a protruding structure of a micromechanical structure according to a fourth embodiment of the present invention;

[0035] Fig.10 A schematic diagram showing a protruding structure of a micromechanical structure according to a fifth embodiment of the present invention;

[0036] Fig.11 A schematic diagram showing a protruding structure of a micromechanical structure according to a sixth embodiment of the present invention;

[0037] Fig.12 A schematic diagram showing a protruding structure of a micromechanical structure according to a seventh embodiment of the present invention;

[0038] Fig.13 A schematic diagram showing a protruding structure of a micromechanical structure according to an eighth embodiment of the present invention;

[0039] Fig.14 A schematic diagram showing a protruding structure of a micromechanical structure according to a ninth embodiment of the present invention;

[0040] Fig.15 A partial schematic diagram showing the manufacturing process of the micro-mechanical structure according to the eighth embodiment of the present invention;

[0041] Figure 16-20 Schematic diagram showing some stages in the manufacturing process of the micromechanical structure according to the eighth embodiment of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same elements are represented by similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale. In addition, some well-known parts may not be shown. For the sake of simplicity, the semiconductor structure obtained after several steps can be described in one figure.

[0043] It should be understood that when describing a structure, when a layer or a region is referred to as being "on" or "over" another layer or another region, it may mean that it is directly on the other layer or another region, or that other layers or regions are included between it and the other layer or another region. Furthermore, if the device is turned over, the layer or a region will be "below" or "beneath" another layer or another region.

[0044] If the purpose is to describe the situation of being directly on another layer or another area, this article will use the expression "directly on..." or "on... and adjacent to...".

[0045] Many specific details of some embodiments of the present invention are described below, such as device structures, materials, dimensions, processing techniques and technologies, so that the present invention can be more clearly understood. However, as those skilled in the art will appreciate, the present invention may be implemented without following these specific details.

[0046] The present invention may be embodied in various forms, some examples of which will be described below.

[0047] Figure 1The schematic diagram of the micromechanical structure of the first embodiment of the present invention is shown. In the figure, the micromechanical structure includes: a substrate 100, a first sacrificial layer 210 and a first structural layer 310, wherein the first sacrificial layer 210 is located on the substrate 100, the first structural layer 310 is located on the first sacrificial layer 210, the first sacrificial layer 210 includes a first cavity 211 located below the first structural layer 310, and the first structural layer 310 includes a protruding structure 311 protruding toward the substrate 100, and the protruding structure 311 is, for example, arc-shaped, so that the surface of the protruding structure 311 facing the substrate 100 is an arched arc surface or at least a part of a spherical surface, so as to form a top 3110 that is approximately dotted. This design can prevent the first structural layer 310 from being adjacent to the structure below it ( Figure 1 Adhesion occurs to the substrate 100).

[0048] Specifically, the substrate 100 is, for example, a silicon substrate, the material of the first sacrificial layer 210 includes, for example, at least one of silicon oxide, borosilicate glass, phosphosilicate glass, and borophosphosilicate glass, and the material of the first structural layer 310 includes, for example, at least one of polycrystalline silicon, amorphous silicon, and silicon nitride. The arc-shaped convex structure 311 not only has a high structural strength, but also has a radius that can be flexibly adjusted to meet the needs of various structural scenarios while maintaining the top 3110 in an approximately point shape.

[0049] Further, the protruding structure 311 has a preset height h, and the preset height h can be used to adjust the maximum downward vibration amplitude of the first structural layer 310. Specifically, the height of the first cavity 211 is, for example, H. When the first structural layer 310 is not provided with the protruding structure 311, the maximum downward amplitude of the first structural layer 310 is, for example, H. When the solution of the present application is adopted, the first structural layer 310 includes a protruding structure 311 with a preset height h, and the maximum downward amplitude of the first structural layer 310 is the difference between the height H of the first cavity 211 and the preset height h of the protruding structure 311, that is, the maximum downward amplitude of the first structural layer 310 is Hh. The maximum vibration amplitude of the first structural layer 310 toward the side of the protruding structure 311 can be effectively adjusted by the protruding structure 311. Furthermore, compared with the full-plane structural layer design, the protruding structure 311 not only changes the structure of the area, but also increases some weight. The protruding structure 311 can also serve as a counterweight to adjust the performance of the first structural layer 310.

[0050] Of course, in order to form the first cavity 211 in the first sacrificial layer 210 , the first structural layer 310 further includes a second etching window 312 , through which the first sacrificial layer 210 is etched to form the first cavity 211 , and the first cavity 211 is connected to the outside through the second etching window 312 .

[0051] Figure 2 FIG. 1 is a schematic diagram showing the manufacturing process of the micromechanical structure according to the first embodiment of the present invention. Figure 3-Figure 6 The schematic diagram of each stage in the process of manufacturing the micro-mechanical structure of the first embodiment of the present invention is as follows. Figure 3-6 The production process of this mechanical structure is described.

[0052] The fabrication process of the micromechanical structure includes the following steps:

[0053] In step S10: forming a first sacrificial layer on the substrate; this step is similar to Figure 3 Correspondingly, the substrate 100 is, for example, a silicon substrate, and a first sacrificial layer 210 is deposited on the substrate 100 by a deposition process. The first sacrificial layer 210 is, for example, formed of at least one material selected from silicon oxide, borosilicate glass, phosphosilicate glass, and borophosphosilicate glass.

[0054] A first sacrificial layer 210 and a first structural layer 310 are formed on the substrate 100; Figure 3 Correspondingly, the substrate 100 is made of, for example, single crystal silicon or polycrystalline silicon, and the first sacrificial layer 210 is made of, for example, silicon oxide or phosphorus silicon glass. Since a portion of the first structural layer 310 is ultimately used as a movable part that can be deformed freely, the first structural layer 310 is, for example, a composite layer made of one or more materials selected from polycrystalline silicon, single crystal silicon, amorphous silicon, and silicon nitride, so as to enhance the mechanical properties of the first structural layer 310 to meet the use requirements. Of course, the micromechanical structure can also be manufactured on the basis of other adjacent structures, by replacing the substrate 100 with other adjacent structures that are not sacrificial layers, and manufacturing the micromechanical structure on the basis of other adjacent structures.

[0055] Step S20 and step S30 are Figure 4 Corresponding.

[0056] In step S20: a first mask layer is formed on the first sacrificial layer, and a first etching window is formed on the first mask layer; specifically, a deposition process is used to form a first mask layer 400 on the first sacrificial layer 210, and the first mask layer 400 is, for example, at least one of photoresist, polysilicon, silicon nitride, and metal, and then a photolithography or etching process is used to form a first etching window 410 on the first mask layer 400 that penetrates the upper and lower surfaces of the first mask layer 400, and the first etching window 410 is, for example, in the shape of a dot.

[0057] In step S30: the first sacrificial layer is etched through the first etching window to form a first pit in the first sacrificial layer; specifically, a dry or wet isotropic etching process is adopted to etch the first sacrificial layer 210 through the first etching window 410 to form a first pit 211, and the first pit 211 is used to assist in the formation of a subsequent protruding structure, and the bottom plane of the first pit 211 corresponds to the shape of the first etching window 410, and the side wall of the first pit 211 is, for example, an arc shape.

[0058] Step S40 and step S50 are Figure 5 Corresponding.

[0059] In step S40: the first mask layer is removed; specifically, according to the material of the first mask layer, a corresponding process is selected to remove the first mask layer 400.

[0060] In step S50: a structural layer material is deposited on the surface of the first sacrificial layer to form a first structural layer; specifically, after removing the first mask layer 400, the upper surface of the first sacrificial layer 210 has a first pit 211, and a structural layer material is deposited on the surface of the first sacrificial layer 210 to form a first structural layer 310, and the structural layer material includes at least one of polycrystalline silicon, amorphous silicon, and silicon nitride. The deposited structural layer material will fill the first pit 211 on the surface of the first sacrificial layer 210, thereby forming a corresponding protruding structure 311 at the first pit 211.

[0061] Step S60 and step S70 are Figure 6 Corresponding.

[0062] In step S60 : a second etching window is formed on the first structure layer; specifically, the first structure layer 310 is etched by an etching process to form a second etching window 312 on the first structure layer 310 that penetrates the upper and lower surfaces of the first structure layer 310 .

[0063] In step S70: the first sacrificial layer is etched through the second etching window to form a first cavity in the first sacrificial layer; specifically, an etching process similar to step S30 is adopted to etch the first sacrificial layer 210 below the first structural layer 310 through the second etching window 312, so that the first sacrificial layer 210 forms a first cavity 211 below the first structural layer 310 having the protruding structure 311, so that the first structural layer 310 including the protruding structure 311 is partially suspended and can be deformed freely to form a movable mechanical structure such as a diaphragm.

[0064] Figure 7The schematic diagram of the micromechanical structure of the second embodiment of the present invention is shown. The second embodiment has a first structure layer 310 similar to the first embodiment. The difference between the second embodiment and the first embodiment is that in the micromechanical structure of the second embodiment, a second structure layer 320 is further arranged between the first structure layer 310 and the substrate 100. The second sacrificial layer 220, the second structure layer 320, the first sacrificial layer 210, and the first structure layer 310 are arranged on the substrate 100 from bottom to top. The second sacrificial layer 220 also has an etching window for etching the second sacrificial layer 220 so that the second structure layer 320 is suspended. The point-like top 311 of the protruding structure 310 of the first structure layer 310 can effectively prevent the first structure layer 310 from being bonded to the second structure layer 320. The material of the second structure layer 320 includes, for example, one or more of silicon, polycrystalline silicon, amorphous silicon, and silicon nitride. Of course, a third sacrificial layer and a third structure layer can also be continuously arranged above the first structure layer 310, so as to form a three-layer movable structure stacked up and down.

[0065] Although the first structural layer of the first embodiment of the present invention is a single-layer structure, the single-layer structure can be a conductive layer or a dielectric layer; however, according to specific requirements, the first structural layer of the present invention can also be a double-layer or multi-layer structure, using a stacked conductive layer, a stacked dielectric layer, or a stacked composite layer composed of a conductive layer and a dielectric layer. The conductive layer includes, for example, polycrystalline silicon or amorphous silicon, and the dielectric layer includes, for example, silicon nitride. Taking the double-layer structure as an example, see Figures 8 to 12 , which respectively show schematic diagrams of the protruding structures of the micromechanical structures of the third to seventh embodiments of the present invention, wherein the first structure layer 310 of the present invention includes a first substructure layer 3101 and a second substructure layer 3102, the first substructure layer 3101 is located below the second substructure layer 3102 and connected to the second substructure layer 3102, as shown in FIG. Figure 8 As shown, the protruding structure is formed only by the first substructure layer 3101, and the second substructure layer 3102 is a common planar diaphragm. The cross section of the first substructure layer 3101 is, for example, semicircular, and the cross section of the second substructure layer 3102 is, for example, rectangular; Fig. 9 As described above, the cross section of the first substructure layer 3101 is, for example, a "F" shape protruding downward, and the cross section of the second substructure layer 3102 is, for example, a "convex" shape matching the first substructure layer 3101; Fig.10 As shown, the cross section of the first substructure layer 3101 is, for example, an arch, and the cross section of the second substructure layer 3102 is, for example, a convex shape matching the first substructure layer 3101; Fig.11 As shown, the cross section of the first substructure layer 3101 is, for example, an arch, and the cross section of the second substructure layer 3102 is, for example, a cross-section that matches the first substructure layer 3101; Fig.12As shown, the cross section of the first substructure layer 3101 is, for example, an “X” shape, and the cross section of the second substructure layer 3102 is, for example, an “X” shape matching the first substructure layer 3101 .

[0066] By selecting the various double-layer structures or other multi-layer structures shown above, the requirements for the size, performance, strength, weight, etc. of the first structural layer can be met.

[0067] Fig.13 and Fig.14 Schematic diagrams showing the protruding structures of the micromechanical structures of the eighth embodiment and the ninth embodiment of the present invention respectively; Fig.13 As shown, the protrusion structure 311 of the present invention is composed of, for example, a first protrusion 3111 and a second protrusion 3112. The first protrusion 3111 is cylindrical, such as a cylinder, a prism, etc., and the second protrusion 3112 is arc-shaped. The second protrusion 3112 is located on the bottom surface of the first protrusion 3111. Similarly, Fig.14 As shown, the first protrusion 3111 may also be in the shape of a table, such as a truncated cone, a prism, etc., and the second protrusion 3112 may also be in the shape of an arc. By adopting a combination of the first protrusion 3111 and the second protrusion 3112, the longitudinal dimension of the protrusion structure 311 can be further increased, thereby changing the maximum vibration amplitude of the protrusion structure 311 of the first structural layer 310 toward one side.

[0068] Since the protrusion structure of the eighth embodiment is composed of two protrusions, compared with the protrusion structure of the first embodiment, its manufacturing process needs to add some steps; see Fig.15 , which shows a schematic diagram of a portion of the additional process flow of the manufacturing process of the micromechanical structure of the eighth embodiment of the present invention compared to the first embodiment, and accordingly, Figures 16 to 20 FIG. 1 is a schematic diagram showing some stages in the process of manufacturing the micromechanical structure of the eighth embodiment of the present invention. In order to highlight the difference between the eighth embodiment and the first embodiment, Figures 16 to 20 A similar substrate 100 is omitted.

[0069] The micromechanical structure of the eighth embodiment can be manufactured by using steps S10 to S70 similar to those of the first embodiment, except that a step S40 is added between step S50. Fig.15 Steps S41 to S43 shown are specifically:

[0070] After step S40, the following is formed: Fig.16 In the structure shown, the first mask layer 400 is removed from the first sacrificial layer 210 , and a first pit 211 is formed on the surface of the first sacrificial layer 210 .

[0071] In step S41: a second mask layer 600 is formed, and a third etching window 610 is formed on the second mask layer 600; this step is similar to Fig.17 Corresponding; specifically, a second mask layer 600 is formed on the upper surface of the first sacrificial layer 210, and the second mask layer 600 is etched by a photolithography process to form a third etching window 610 on the second mask layer 600, and the third etching window 610 corresponds to the first pit 211, and the size of the third etching window 610 is, for example, larger than the size of the edge of the pit 211.

[0072] In step S42: the first sacrificial layer 210 is etched through the second mask layer 600 to form a second pit 212 in the first sacrificial layer 210; this step is similar to Fig.18 Correspondingly; specifically, the first sacrificial layer 210 is etched in the longitudinal direction through the third etching window 610 on the second mask layer 600, so that a second pit 212 is formed in the first sacrificial layer 210, and the second pit 212 includes, for example, a columnar portion 2121 located at the top, and an arc portion 2122 located at the bottom of the columnar portion 2121 and protruding downward. Further, if the columnar portion 2121 in the second pit 212 is replaced with a terrace, the size of the third etching window 610 and the etching process can be changed accordingly, and no further description is given.

[0073] In step S43: remove the second mask layer 600; this step is similar to Fig.19 Correspondingly, according to the material of the second mask layer 600 , a corresponding process is selected to remove the second mask layer 600 on the surface of the first sacrificial layer 210 .

[0074] Through Fig.15 After step S43 shown in FIG. 1 , the same manufacturing process as in the first embodiment is continued. Figure 2 In step S50, a structural layer material is deposited on the surface of the first sacrificial layer to form a first structural layer; Fig.19 On the basis of the first sacrificial layer 210, a structural layer material is deposited on the surface of the first sacrificial layer 210 to form Fig. 20 In the first structural layer 310 shown, the protrusion structure 311 of the first structural layer 310 is composed of a first cylindrical protrusion and a second arc-shaped protrusion located at the bottom surface of the first protrusion.

[0075] The micromechanical structure and manufacturing method provided by the embodiments of the present invention, by arranging an arc-shaped protruding structure on the structural layer, the protruding structure is generally in the shape of a hemispherical arc, has high structural strength, and its top is approximately point-shaped, which can prevent the first structural layer from adhering to the adjacent structure during deformation or movement, thereby avoiding device failure due to adhesion; the arc-shaped protruding structure has high mechanical strength, and the size and radius of the protruding structure can be flexibly adjusted according to needs, which can meet the application scenarios of various structural gaps.

[0076] Furthermore, the protruding structure has a different weight than the planar structure, and the protruding structure can also be used as a counterweight to adjust the vibration performance of the first structural layer; the protruding structure, for example, also has a preset height, and the movable range of the structural layer is limited by the protruding structure, thereby controlling the maximum amplitude of the structural layer. The protruding structure can also include a first protrusion and a second protrusion, which is combined with a columnar or table shape and a hemispherical arc, which can achieve anti-adhesion while ensuring structural strength, and can flexibly adjust the overall length, width and proportion of the protruding structure to meet the needs of various application scenarios.

[0077] The method for manufacturing a micromechanical structure provided in an embodiment of the present invention involves a processing technology that is mature and reliable, simple and easy to implement, and can conveniently obtain a first structural layer with a protruding structure, and then manufacture a corresponding micromechanical structure. This manufacturing method can not only meet a variety of needs, but also has a simple process and high production efficiency.

[0078] In the above description, the technical details of the patterning and etching of each device are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0079] The embodiments of the present invention are described above. However, these embodiments are only for the purpose of illustration and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, a person skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A micromechanical structure, characterized in that: include: substrate; A first sacrificial layer, located on the substrate, wherein a first cavity is formed in the first sacrificial layer; A first structural layer, located on the first sacrificial layer, the first structural layer comprising a protruding structure protruding toward the substrate; The first cavity makes at least part of the first structural layer including the protruding structure suspended, and the surface of the protruding structure facing the substrate includes an arc shape to prevent the first structural layer from adhering to the adjacent structure thereunder.

2. The micromechanical structure according to claim 1, characterized in that: The surface of the protruding structure facing the substrate includes an arched curved surface or at least a partial spherical surface.

3. The micromechanical structure according to claim 1, characterized in that: The protrusion structure includes a first protrusion and a second protrusion, the first protrusion is a column or a table, the second protrusion is located at the bottom of the first protrusion, and a surface of the second protrusion facing the substrate includes an arched curved surface or at least a partial spherical surface.

4. The micromechanical structure according to claim 1, characterized in that: The first structural layer includes a plurality of stacked sub-structural layers, and the protruding structure is composed of at least two sub-structural layers.

5. The micromechanical structure according to claim 4, characterized in that: The raised structure includes a first substructure layer and a second substructure layer located above the first substructure layer, the longitudinal section of the first substructure layer includes at least one of a bow shape, an arch shape, and an I-shape, and the longitudinal section of the second substructure layer includes at least one of a rectangle shape, a convex shape, and an I-shape corresponding to the first substructure layer.

6. The micromechanical structure according to claim 1, characterized in that: The protruding structure has a preset height to limit the maximum vibration amplitude of the first structure layer in the protruding direction of the protruding structure.

7. The micromechanical structure according to claim 1, characterized in that: The protruding structure has a specific weight and serves as a counterweight for the first structural layer. The vibration performance of the first structural layer can be adjusted by adjusting the weight of the protruding structure.

8. The micromechanical structure according to claim 1, characterized in that: The first structural layer includes a plurality of the protruding structures, and the plurality of the protruding structures are located in different regions of the first structural layer to change the mechanical properties, electrical properties and weight of corresponding regions of the first structural layer.

9. The micromechanical structure according to claim 1, characterized in that: The material of the first sacrificial layer includes at least one of silicon oxide, borosilicate glass, phosphosilicate glass or borophosphosilicate glass.

10. The micromechanical structure according to claim 1, characterized in that: The first structural layer includes at least one of polycrystalline silicon, single crystal silicon, amorphous silicon, and silicon nitride.

11. The micromechanical structure according to claim 1, characterized in that: The first cavity is formed by etching the first sacrificial layer through an etching window on the first structural layer, and the etching process of the first sacrificial layer includes at least one of wet etching using a buffered oxide etchant and gas-phase dry etching using hydrofluoric acid.

12. The micromechanical structure according to claim 11, characterized in that: The etching window and the protruding structure are staggered in the plane where the first structural layer is located.

13. The micromechanical structure according to claim 1, characterized in that: The micromechanical structure is used in a MEMS chip.

14. A method for manufacturing a micromechanical structure, characterized in that: include: forming a first sacrificial layer on the substrate; forming a first mask layer on the first sacrificial layer, and forming a first etching window on the first mask layer; Etching the first sacrificial layer through the first etching window to form a first pit in the first sacrificial layer; removing the first mask layer; Depositing a structural layer material on the surface of the first sacrificial layer to form a first structural layer; forming a second etching window on the first structural layer, Etching the first sacrificial layer through the second etching window to form a first cavity in the first sacrificial layer; The first cavity makes the part of the first structural layer including the protruding structure suspended in the air to form a movable first structural layer with the protruding structure.

15. The manufacturing method according to claim 14, characterized in that: The bottom plane of the first pit corresponds to the shape of the first etching window, and the side surface of the first pit is arc-shaped.

16. The manufacturing method according to claim 15, characterized in that: The first pit is formed by a dry or wet isotropic etching process, and the first pit is used to assist in the formation of the protruding structure.

17. The manufacturing method according to claim 14, characterized in that: After removing the first mask layer, before depositing a structural layer material on the surface of the first sacrificial layer to form a first structural layer, the method further includes: forming a second mask layer, and forming a third etching window on the second mask layer; Etching the first sacrificial layer through the second mask layer to form a second pit in the first sacrificial layer; removing the second mask layer; Among them, the position of the third etching window corresponds to the first pit, and the size of the third etching window is not less than the size of the first pit; the second pit is formed on the basis of the first pit, and the depth of the second pit is greater than the depth of the first pit.

18. The manufacturing method according to claim 17, characterized in that: The protrusion structure includes a first protrusion and a second protrusion, the first protrusion is a column or a table, the second protrusion is located at the bottom of the first protrusion, and a surface of the second protrusion facing the substrate includes an arched curved surface or at least a partial spherical surface.

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