Micromechanical structure

Abstract

The utility model discloses a micromechanical structure. The micromechanical 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] This utility model relates to the field of microelectronic device technology, and more specifically, to a micromechanical structure. Background Technology

[0002] Micro-Electro-Mechanical Systems (MEMS) typically include micromechanical structures to achieve specific functions. MEMS usually consist of a sacrificial layer and a structural layer. By etching the sacrificial layer (also known as releasing), a release cavity is formed beneath the structural layer, thereby suspending part of the structural layer to form a movable structure.

[0003] During device operation, when the movable structure deforms or moves, it can easily adhere to adjacent structures, causing device failure.

[0004] To prevent the movable structure from adhering to adjacent structures, protrusions are usually placed on the movable structure to reduce the contact area between the movable structure and the adjacent structures. However, the top of the protrusion is still flat, and it still has the problem of adhesion to adjacent structures. Moreover, the edges of the protrusion can be bumped and broken, resulting in structural damage. Furthermore, the presence of the protrusion will also affect the mechanical strength of the entire movable structure in that area, creating a weak point in the strength of the entire movable structure in that 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 movable structures, reduce the risk of adhesion between structural layers and adjacent structures, and enhance their structural strength. Utility Model Content

[0006] The purpose of this invention is to provide a micromechanical structure to solve problems in existing technologies, such as device failure caused by adhesion between adjacent structures, insufficient structural layer strength, and inability to meet specific maximum amplitude requirements. This improves the reliability and stability of the micromechanical mechanism and expands its application scenarios.

[0007] This invention provides a micromechanical structure, comprising: a substrate; a first sacrificial layer located on the substrate, wherein a first cavity is formed in the first sacrificial layer; and a first structural layer located on the first sacrificial layer, wherein the first structural layer includes a protruding structure protruding toward the substrate; wherein the first cavity suspends at least a portion of the first structural layer including the protruding structure, and the surface of the protruding structure facing the substrate is arc-shaped to prevent the first structural layer from adhering to its adjacent structure below it.

[0008] Optionally, the surface of the protrusion structure facing the substrate includes an arched arc or at least a partially spherical surface.

[0009] Optionally, the protruding structure comprises a first protrusion and a second protrusion, the first protrusion is a column or a platform, and the second protrusion is located at the bottom of the first protrusion, and the second protrusion comprises an arc surface or at least a partial spherical surface towards the one side surface of the substrate.

[0010] Optionally, the first structure layer comprises a plurality of stacked substructure layers, and the protruding structure is composed of at least two substructure layers.

[0011] Optionally, the protruding structure comprises a first substructure layer and a second substructure layer located above the first substructure layer, the longitudinal section of the first substructure layer comprises at least one of an arc shape, an arch shape, and a U shape, and the longitudinal section of the second substructure layer comprises at least one of a rectangular shape, a convex shape, and a U shape corresponding to the first substructure layer.

[0012] Optionally, 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.

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

[0014] Optionally, the first structure layer comprises a plurality of the protruding structures, and the plurality of the protruding structures are located in different regions of the first structure layer to change the mechanical performance, electrical performance, and counterweight of the corresponding regions of the first structure layer.

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

[0016] Optionally, the first structure layer comprises at least one of polycrystalline silicon, monocrystalline silicon, amorphous silicon, or silicon nitride.

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

[0018] Optionally, the etching window is misaligned with the protruding structure in the plane where the first structure layer is located.

[0019] Optionally, the micro-mechanical structure is used in a MEMS chip.

[0020] The micromechanical structure provided in this embodiment of the utility model has an arc-shaped protrusion on the structural layer. The protrusion is hemispherical in shape and has high structural strength. Its top is approximately point-shaped, which can prevent the first structural layer from adhering to the adjacent structure during deformation or movement, thus avoiding device failure due to adhesion. The arc-shaped protrusion has high mechanical strength, and the size and radius of the protrusion can be flexibly adjusted according to requirements, which can meet the application scenarios of various structural gaps.

[0021] Furthermore, this protruding structure has a different weight compared to the planar structure, and can also act as a counterweight to adjust the vibration performance of the first structural layer. For example, the protruding structure may also have a preset height, which limits the movable range of the structural layer and thus controls its maximum amplitude. The protruding structure may also include a first protrusion and a second protrusion, employing a combination of columnar or frustum-shaped structures with hemispherical arcs. This achieves anti-adhesion while ensuring structural strength, and the overall length, width, and proportions of the protruding structure can be flexibly adjusted to meet the needs of various application scenarios. Attached Figure Description

[0022] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the present invention with reference to the accompanying drawings.

[0023] Figure 1 A schematic diagram of the micromechanical structure of the first embodiment of this utility model is shown;

[0024] Figure 2 A schematic diagram of the fabrication process of the micromechanical structure according to the first embodiment of this utility model is shown;

[0025] Figures 3-6 The diagram shows the various stages of the fabrication process of the micromechanical structure according to the first embodiment of this utility model;

[0026] Figure 7 A schematic diagram of the micromechanical structure of the second embodiment of this utility model is shown;

[0027] Figure 8 A schematic diagram of the protrusion structure of the micromechanical structure according to the third embodiment of this utility model is shown;

[0028] Figure 9 A schematic diagram of the protrusion structure of the micromechanical structure according to the fourth embodiment of this utility model is shown;

[0029] Figure 10 A schematic diagram of the protrusion structure of the micromechanical structure according to the fifth embodiment of this utility model is shown;

[0030] Figure 11 A schematic diagram of the protrusion structure of the micromechanical structure according to the sixth embodiment of this utility model is shown;

[0031] Figure 12 A schematic diagram of a protrusion structure of a micro-mechanical structure of a seventh embodiment of the present application is shown;

[0032] Figure 13 A schematic diagram of a protrusion structure of a micro-mechanical structure of an eighth embodiment of the present application is shown;

[0033] Figure 14 A schematic diagram of a protrusion structure of a micro-mechanical structure of a ninth embodiment of the present application is shown;

[0034] Figure 15 A partial schematic diagram of a manufacturing process of a micro-mechanical structure of the eighth embodiment of the present application is shown;

[0035] Figures 16-20 A schematic diagram of some stages of a manufacturing process of a micro-mechanical structure of the eighth embodiment of the present application is shown. DETAILED DESCRIPTION

[0036] The present application will be described in more detail by referring to the attached drawings. Like elements are denoted by like reference numerals throughout the various drawings. Individual parts in the drawings are not necessarily to scale for the sake of clarity. Furthermore, certain known elements can not be shown. For the sake of brevity, a semiconductor structure obtained after several steps can be described in one drawing.

[0037] It is to be understood that when a layer, a region is referred to as being "on" or "above" another layer, another region, it can be directly on the other layer, the other region or intervening layers or regions can also be present. In addition, when a device is turned over, the layer, the region will be "under" or "below" the other layer, the other region.

[0038] If for the sake of description, a layer, a region is referred to as being "directly on" or "on and adjacent to" another layer, another region, the expression is used.

[0039] Many specific details of some embodiments of the present application are described below in order to provide a thorough understanding of the present application. However, as will be readily understood by one skilled in the art, the present application can be practiced without

[0040] The present application can be presented in various forms, some examples of which will be described below.

[0041] Figure 1The utility model discloses a micro mechanical structure, which comprises a substrate, a first sacrificial layer and a first structure layer. Figure 1 The first structure layer is provided with a protruding structure.

[0042] The substrate is made of silicon, and the first sacrificial layer is made of at least one of silicon oxide, borosilicate glass, phosphosilicate glass and borophosphosilicate glass. The protruding structure has a preset height, which can adjust the maximum vibration amplitude of the first structure layer.

[0043] The protruding structure can also serve as a counterweight to adjust the performance of the first structure layer.

[0044] The first structure layer further comprises a second etching window.

[0045] Figure 2The manufacturing process of the micro-mechanical structure is shown in the first embodiment of the utility model, Figures 3-6 The manufacturing process of the micro-mechanical structure is shown in the first embodiment of the utility model, Figures 3-6 The manufacturing process of the micro-mechanical structure is shown in the first embodiment of the utility model,

[0046] The manufacturing process of the micro-mechanical structure is shown in the first embodiment of the utility model,

[0047] In step S10, a first sacrificial layer is formed on the substrate; this step corresponds to Figure 3 Corresponding, wherein the substrate 100 is for example a silicon substrate, a deposition process is used to deposit the first sacrificial layer 210 on the substrate 100, the first sacrificial layer 210 is for example formed by using at least one material selected from the group consisting of silicon oxide, borosilicate glass, phosphosilicate glass and borophosphosilicate glass.

[0048] The first sacrificial layer 210 and the first structural layer 310 are formed on the substrate 100; this step corresponds to Figure 3 Corresponding, wherein the substrate 100 is for example a single crystal silicon or polycrystalline silicon material, the first sacrificial layer 210 is for example an oxide of silicon or a phosphosilicate glass material, since part of the first structural layer 310 is finally used as a movable component that can be freely deformed, the first structural layer 310 is for example a composite layer composed of one or more materials selected from the group consisting of polycrystalline silicon, single crystal silicon, amorphous silicon and silicon nitride, so as to enhance the mechanical properties of the first structural layer 310 and meet the use requirements. Of course, the micro-mechanical structure can also be manufactured on the basis of other adjacent structures, the substrate 100 is replaced by other adjacent structures without a sacrificial layer, and the micro-mechanical structure can be manufactured on the basis of other adjacent structures.

[0049] Step S20 and step S30 correspond to Figure 4 Corresponding.

[0050] 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, the first mask layer 400 is for example at least one material selected from the group consisting of photoresist, polycrystalline silicon, silicon nitride and metal, and then a photolithography or etching process is used to form a first etching window 410 penetrating the upper and lower surfaces of the first mask layer 400, the first etching window 410 is for example a dot.

[0051] In step S30, the first etching window is used to etch the first sacrificial layer to form a first recess; specifically, a dry or wet isotropic etching process is used to etch the first sacrificial layer 210 through the first etching window 410 to form a first recess 211, which is used to assist the formation of a subsequent protruding structure. The bottom plane of the first recess 211 corresponds to the shape of the first etching window 410, and the sidewall of the first recess 211 is, for example, a circular arc.

[0052] Steps S40 and S50 correspond to Figure 5 .

[0053] 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.

[0054] In step S50, a structure layer material is deposited on the surface of the first sacrificial layer to form a first structure layer; specifically, after the first mask layer 400 is removed, the upper surface of the first sacrificial layer 210 has the first recess 211. The structure layer material is deposited on the surface of the first sacrificial layer 210 to form a first structure layer 310. The structure layer material includes at least one of polysilicon, amorphous silicon, and silicon nitride. The deposited structure layer material fills the first recess 211 on the surface of the first sacrificial layer 210, thereby forming a corresponding protruding structure 311 at the first recess 211.

[0055] Steps S60 and S70 correspond to Figure 6 .

[0056] In step S60, a second etching window is formed on the first structure layer; specifically, an etching process is used to etch the first structure layer 310 to form a second etching window 312 that penetrates the upper and lower surfaces of the first structure layer 310.

[0057] In step S70, the first etching window is used to etch the first sacrificial layer to form a first recess; specifically, a dry or wet isotropic etching process is used to etch the first sacrificial layer 210 through the first etching window 410 to form a first recess 211, which is used to assist the formation of a subsequent protruding structure. The bottom plane of the first recess 211 corresponds to the shape of the first etching window 410, and the sidewall of the first recess 211 is, for example, a circular arc.

[0058] Figure 7The utility model discloses a second embodiment's schematic diagram of micro mechanical structure is shown, this second embodiment has with the first embodiment similar first structure layer 310, the second embodiment with the first embodiment's difference lies in, in the micro mechanical structure of this second embodiment, first structure layer 310 and substrate 100 still be provided with second structure layer 320 between, on substrate 100 from below to above, second sacrificial layer 220, second structure layer 320, first sacrificial layer 210, first structure layer 310 are sequentially provided with, wherein, second sacrificial layer 220 also have etching window for etching second sacrificial layer 220 makes second structure layer 320 hang, the similar point of first structure layer 310's convex structure 310 top 311 can effectively prevent first structure layer 310 and second structure layer 320 occur bonding, the material of second structure layer 320 for example includes one or more of silicon, polysilicon, amorphous silicon, silicon nitride.Certainly, above first structure layer 310, third sacrificial layer and third structure layer can also be continuously provided, thereby forming the three movable structures of upper and lower stacking.

[0059] Although the first structure layer of the first embodiment of the utility model is single-layer structure, the single-layer structure can be conductive layer or dielectric layer, but according to specific demand, the first structure layer of the utility model can also be double-layer or multi-layer structure, adopts the conductive layer of multi-layer stacking, the dielectric layer of multi-layer stacking or the stacked composite layer formed by multi-layer conductive layer and dielectric layer. Conductive layer for example includes polysilicon or amorphous silicon, dielectric layer for example includes silicon nitride. Taking double-layer structure as an example, referring to Figures 8 to 12 , it respectively shows the schematic diagram of convex structure of the micro mechanical structure of the third to seventh embodiments of the utility model, wherein, the first structure layer 310 of the utility model includes first substructure layer 3101 and second substructure layer 3102, first substructure layer 3101 is below second substructure layer 3102 and is connected with second substructure layer 3102, as shown in Figure 8 , convex structure is only formed with first substructure layer 3101, and second substructure layer 3102 is common plane diaphragm, the section of first substructure layer 3101 for example is semicircle, and the section of second substructure layer 3102 for example is rectangle; Figure 9 As shown, the section of first substructure layer 3101 for example is inverted V-shaped, and the section of second substructure layer 3102 for example is convex-shaped matched with first substructure layer 3101; Figure 10 As shown, the section of first substructure layer 3101 for example is arch-shaped, and the section of second substructure layer 3102 for example is convex-shaped matched with first substructure layer 3101; Figure 11 As shown, the section of first substructure layer 3101 for example is arch-shaped, and the section of second substructure layer 3102 for example is inverted V-shaped matched with first substructure layer 3101; Figure 12As shown, the cross-section of the first substructure layer 3101 is, for example, a Z-shape, and the cross-section of the second substructure layer 3102 is, for example, a Z-shape that matches the first substructure layer 3101.

[0060] By selecting the various double-layer structures or other multi-layer structures shown above, the requirements for the size, performance, strength, and counterweight of the first structural layer can be met.

[0061] Figure 13 and Figure 14 Schematic diagrams of the protruding structures of the micromechanical structures in the eighth and ninth embodiments of this utility model are shown respectively; as follows: Figure 13 As shown, the protruding structure 311 of this utility model is composed of, for example, a first protrusion 3111 and a second protrusion 3112. The first protrusion 3111 is cylindrical, such as a cylinder or prism, and the second protrusion 3112 is arc-shaped, located on the bottom surface of the first protrusion 3111; similarly, as... Figure 14 As shown, the first protrusion 3111 can also be frustum-shaped, such as frustum of a cone or frustum of a prism, and the second protrusion 3112 can also be arc-shaped. By using the 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 facing one side.

[0062] Since the protrusion structure of the eighth embodiment is composed of two protrusions, its manufacturing process requires additional steps compared to the protrusion structure of the first embodiment; see [link to documentation]. Figure 15 It shows a schematic diagram of the additional process in the fabrication of the micromechanical structure according to the eighth embodiment of the present invention compared to the first embodiment. Accordingly, Figures 16 to 20 The diagram shows some stages in the fabrication process of the micromechanical structure according to the eighth embodiment of this utility model. To highlight the difference between the eighth embodiment and the first embodiment, [details omitted]. Figures 16 to 20 The similar substrate 100 is omitted in the text.

[0063] Fabricating the micromechanical structure of the eighth embodiment can still employ steps S10 to S70 similar to those of the first embodiment. The difference lies in the need to add an additional step between S40 and S50. Figure 15 Steps S41 to S43 shown are specifically as follows:

[0064] After step S40, the following is formed: Figure 16 The structure shown has the first mask layer 400 removed from the first sacrificial layer 210, and a first pit 211 formed on the surface of the first sacrificial layer 210.

[0065] 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 corresponds to Figure 17 In particular, the second mask layer 600 is formed on the surface of the first sacrificial layer 210, and the second mask layer 600 is etched by using a photolithography process, so as to form the third etching window 610 on the second mask layer 600, the third etching window 610 corresponds to the first recess 211, and the size of the third etching window 610 is greater than the size of the edge of the recess 211, for example.

[0066] In step S42, the first sacrificial layer 210 is etched by using the second mask layer 600, so as to form a second recess 212 in the first sacrificial layer 210; this step corresponds to Figure 18 In particular, the first sacrificial layer 210 is etched in the longitudinal direction by using the third etching window 610 on the second mask layer 600, so as to form the second recess 212 in the first sacrificial layer 210, the second recess 212 includes a columnar portion 2121 located on the upper side and a circular arc portion 2122 located at the bottom of the columnar portion 2121 and protruding downward, for example. Further, if the columnar portion 2121 in the second recess 212 is replaced by a platform, the size of the third etching window 610 and the etching process are changed correspondingly, and details are not described herein.

[0067] In step S43, the second mask layer 600 is removed; this step corresponds to Figure 19 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.

[0068] After step S43 shown in Figure 15 , the same manufacturing process as the first embodiment is continued, and step S50 shown in Figure 2 is performed, in which a structure layer material is deposited on the surface of the first sacrificial layer, so as to form a first structure layer; on the basis of Figure 19 , the structure layer material is deposited on the surface of the first sacrificial layer 210, so as to form a first structure layer 310 shown in Figure 20 , in which the convex structure 311 of the first structure layer 310 is composed of a columnar first convex structure and a circular arc second convex structure located at the bottom of the first convex structure.

[0069] The micro-mechanical structure provided by the embodiment of the utility model, by setting the arc convex structure on the structure layer, the arc convex structure is in a whole hemispherical arc shape, has large structural strength, and the top end is approximately point-shaped, which can prevent the first structure layer from adhering to the adjacent structure during deformation or movement, and avoid the failure of the device due to adhesion; the arc convex structure has large mechanical strength, and the size and radius of the convex structure can be flexibly adjusted according to requirements, so that the application scenarios of various structure gaps can be met.

[0070] Further, the convex structure has different weight compared to the flat structure, and the convex structure can also be used as a counterweight to adjust the vibration performance of the first structure layer; the convex structure also has a preset height, for example, the movable range of the structure layer is limited by the convex structure, thereby controlling the maximum amplitude of the structure layer. The convex structure can also include first convex and second convex, which are combined in a columnar or platform shape with a hemispherical arc, which can prevent adhesion while ensuring structural strength, and the overall length, width and proportion of the convex structure can be flexibly adjusted to meet the needs of various application scenarios.

[0071] In the above description, the patterning, etching and other technical details 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 and the like with the desired shape. In addition, those skilled in the art can also design methods that are not exactly the same as the methods described above to form the same structure. In addition, although each embodiment is described above, this does not mean that the measures in each embodiment cannot be used advantageously in combination.

[0072] The embodiments of the present application are described above. However, these embodiments are only for illustrative purposes, and are not intended to limit the scope of the present application. The scope of the present application is defined by the appended claims and their equivalents. Without departing from the scope of the present application, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should fall within the scope of the present application.

Claims

1. A micromechanical structure, characterized by The application relates to a micro-mechanical structure, comprising: a substrate; a first sacrificial layer on the substrate, wherein a first cavity is formed in the first sacrificial layer; a first structure layer on the first sacrificial layer, wherein the first structure layer comprises a protruding structure protruding towards the substrate, and wherein the surface of the protruding structure towards the substrate comprises an arc-shaped surface to prevent the first structure layer from adhering to the structure below. The surface of the protruding structure towards the substrate comprises an arch-shaped surface or at least a partial spherical surface.

2. The micromechanical structure according to claim 1, characterized in that The protruding structure comprises a first protrusion and a second protrusion, wherein the first protrusion is a column or a platform, and the second protrusion is located at the bottom of the first protrusion, and the surface of the second protrusion towards the substrate comprises an arch-shaped surface or at least a partial spherical surface.

3. The micromechanical structure according to claim 1, characterized in that The first structure layer comprises a plurality of stacked substructure layers, and the protruding structure is composed of at least two substructure layers.

4. The micromechanical structure according to claim 1, characterized in that The protruding structure comprises a first substructure layer and a second substructure layer above the first substructure layer, wherein the longitudinal section of the first substructure layer comprises at least one of an arc shape, an arch shape and a U shape, and the longitudinal section of the second substructure layer comprises at least one of a rectangular shape, a convex shape and a U shape corresponding to the first substructure layer.

5. The micromechanical structure according to claim 4, 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.

6. The micromechanical structure according to claim 1, characterized in that The protruding structure has a specific weight, and the protruding structure serves as a counterweight of the first structure layer, and the vibration performance of the first structure layer is adjusted by adjusting the weight of the protruding structure.

7. The micromechanical structure according to claim 1, characterized in that The first structure layer comprises a plurality of protruding structures, and the plurality of protruding structures are located in different regions of the first structure layer to change the mechanical performance, electrical performance and counterweight of the corresponding regions of the first structure layer.

8. 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 structure layer, and the etching process of the first sacrificial layer comprises at least one of wet etching by using a buffer oxide etchant and gas phase dry etching by using hydrofluoric acid.

9. The micromechanical structure according to claim 1, characterized in that The etching window is staggered with the protruding structure in the plane of the first structure layer.

10. The micromechanical structure according to claim 9, characterized in that The micro-mechanical structure is used in a MEMS chip.

11. The micromechanical structure according to claim 1, characterized in that ​

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