CN117776088A - MEMS device and electronic device - Google Patents

Abstract

The invention provides a MEMS device and an electronic device, the MEMS device comprises: a substrate; a structural layer on the substrate, the structural layer comprising a movable structure and a fixed structure surrounding the movable structure, a gap being present between the movable structure and the fixed structure; and one end of the elastic beam is arranged on the side surface of the fixed structure, which faces the movable structure, and the other end of the elastic beam is a free end. According to the scheme, the elastic beam structure is arranged on the side face, facing the movable structure, of the fixed structure, so that the resetting capability of the movable structure can be improved, the adhesion and locking defects of MEMS devices can be reduced, and the service life, reliability and yield of products are improved.

Description

MEMS device and electronic device

Technical Field

The invention relates to the technical field of semiconductors, in particular to an MEMS device and an electronic device.

Background

MEMS (Micro-Electro-Mechanical System, microelectromechanical system) refers to a Micro system that integrates mechanical components, driving parts, optical systems, electrical control systems into one whole. The MEMS sensor has the advantages of small volume, low power consumption, mass production and the like, and has wide application scenes in a plurality of fields such as smart phones, tablet computers, game machines, automobiles, unmanned aerial vehicles, electronics, aerospace and the like.

However, the MEMS sensor in the related art often generates adhesion and locking phenomena between the movable structure and the fixed structure during operation, so that the movable structure is difficult to reset, and the MEMS sensor cannot normally operate, resulting in reduced product reliability, service life and yield.

Disclosure of Invention

In the summary, a series of concepts in a simplified form are introduced, which will be further described in detail in the detailed description. The summary of the invention is not intended to define the key features and essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In view of the problems existing at present, an aspect of an embodiment of the present invention provides a MEMS device, including:

a substrate;

a structural layer on the substrate, the structural layer comprising a movable structure and a fixed structure surrounding the movable structure, a gap being present between the movable structure and the fixed structure;

and one end of the elastic beam is arranged on the side surface of the fixed structure, which faces the movable structure, and the other end of the elastic beam is a free end.

In one embodiment, the MEMS device further comprises a stopper provided on a side of the elastic beam facing the movable structure.

In one embodiment, the surface of the stopper is circular arc-shaped.

In one embodiment, a gap is formed between the elastic beam and the fixed structure, and the elastic beam deforms toward the gap when the elastic beam is pressed by the movable structure.

In one embodiment, at least one pair of elastic beams is disposed on a side of each of the fixed structures facing the movable structure, and free ends of two elastic beams of each pair of the at least one pair of elastic beams are disposed opposite to each other.

In one embodiment, the MEMS device comprises a MEMS gyroscope, the movable structure comprises a comb structure of the MEMS gyroscope, or the MEMS device comprises a MEMS accelerometer, the movable structure comprises a comb structure of the MEMS accelerometer.

In one embodiment, when the MEMS device comprises a MEMS gyroscope, the movable structure comprises a comb structure of the MEMS gyroscope, the movable structure comprises a first sub-movable structure, a second sub-movable structure, and a third sub-movable structure, wherein:

the first movable sub-structure is used for measuring the angular velocity in the x-axis direction;

the second movable sub-structure is used for measuring the angular velocity in the y-axis direction;

the third sub-movable structure is used for measuring the angular velocity in the z-axis direction.

In one embodiment, when the MEMS device comprises a MEMS accelerometer, the movable structure comprises a comb structure of the MEMS accelerometer, the movable structure comprises a first sub-movable structure, a second sub-movable structure, and a third sub-movable structure, wherein:

the first movable sub-structure is used for measuring acceleration in the x-axis direction;

the second movable sub-structure is used for measuring acceleration in the y-axis direction;

the third sub-movable structure is used for measuring acceleration in the z-axis direction.

In one embodiment, the comb structure includes a fixed comb electrode and a movable comb electrode.

In another aspect, an embodiment of the present invention provides an electronic apparatus, where the electronic apparatus includes the MEMS device described above.

According to the MEMS device and the electronic device, the elastic beam structure is arranged on the side face, facing the movable structure, of the fixed structure, so that the resetting capability of the movable structure can be improved, and the elastic beam is in friction contact with the movable structure in the process of collision to separation, so that the adhesion and locking defects of the MEMS device can be reduced, and the service life, reliability and yield of products are improved.

Drawings

The following drawings are included to provide an understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and their description to explain the principles of the invention.

In the accompanying drawings:

FIG. 1A shows a top view of a MEMS device of the related art;

FIG. 1B is a schematic view showing a process of collision to separation of a fixed structure and a movable structure of a MEMS device according to the related art;

FIG. 2 illustrates a top view of a MEMS device in accordance with an embodiment of the present invention;

FIG. 3 illustrates a schematic partial cross-sectional view of a MEMS device in accordance with an embodiment of the present invention;

FIG. 4 is a schematic view showing the structure of the fixed structure, the elastic beam and the stopper of the MEMS device according to an embodiment of the present invention;

fig. 5 is a schematic diagram showing a process of collision and separation between an elastic beam and a movable structure of a MEMS device according to an embodiment of the present invention.

Detailed Description

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size of layers and regions, as well as the relative sizes, may be exaggerated for clarity. Like numbers refer to like elements throughout.

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, adjacent, connected, or coupled to the other element or layer, 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. It will be understood that, although the terms first, second, third, etc. may be used herein 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.

Spatially relative terms, such as "under," "below," "beneath," "under," "above," "over," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated 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 "under" or "beneath" other elements would then be oriented "on" the other elements or features. Thus, the exemplary terms "below" and "under" may include both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatially relative 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" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 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-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the invention. In this way, variations from the illustrated shape due to, for example, manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the present invention should not be limited to the particular shapes of the regions illustrated herein, but rather include deviations in shapes that result, for example, from manufacturing. For example, an implanted region shown as a rectangle typically has rounded or curved features and/or implant concentration gradients at its edges rather than a binary change from implanted to non-implanted regions. Also, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface over which the implantation is performed. Thus, the regions illustrated 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 present invention.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present specification and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In order to provide a thorough understanding of the present invention, detailed steps and structures will be presented in the following description in order to illustrate the technical solution presented by the present invention. Preferred embodiments of the present invention are described in detail below, however, the present invention may have other embodiments in addition to these detailed descriptions.

In the related art, the MEMS sensor often generates adhesion and locking phenomena between the movable structure and the fixed structure during operation. The reason for this phenomenon is many, for example, when a wet etching process is required to prepare the movable structure and the fixed structure of the MEMS device, however, in the cleaning step after the wet etching process, when the volume of the liquid between the movable structure and the fixed structure is reduced due to evaporation, the contact surfaces of the movable structure and the fixed structure adhere to each other due to the capillary force between the movable structure and the fixed structure, thereby causing the adhesion phenomenon. Even if the movable structure and the fixed structure are not adhered after the wet etching process is finished, substances and other phenomena remained on the surfaces of the movable structure and the fixed structure can adhere together when the contact surfaces of the movable structure and the fixed structure collide with each other under the promotion of inertia force, namely, a locking phenomenon occurs in the operation process. When adhesion or blocking occurs between the movable structure and the fixed structure, the adhesion between the contact surfaces of the two tends to exceed the elastic restoring capability of the movable structure, so that the movable structure cannot spring back to its equilibrium position, which is fatal to the MEMS device, whether adhesion or blocking occurs for a short time or permanently.

In order to reduce the occurrence of the adhesion or blocking phenomenon between the movable structure and the fixed structure, the related art mainly adopts a method for increasing the distance between the movable structure and the fixed structure, however, the method not only can increase the chip size, but also can cause the risk of easily damaging the movable structure and the fixed structure.

As shown in fig. 1A, one solution to the above problem is to provide a plurality of protruding block structures on the side of the fixed structure 110 facing the movable structure 120, and reduce the occurrence of blocking and latch-up phenomena by reducing the contact area of the movable structure 120 with the fixed structure 110. However, as shown in fig. 1B, in this solution, the movable structure 120 and the fixed structure 110 are in hard contact, so that the damage is easy to occur, and the adhesion and locking phenomena still easily occur in this solution.

Therefore, in view of the foregoing technical problems, an embodiment of the present invention proposes a MEMS device, including:

a substrate;

a structural layer on the substrate, the structural layer comprising a movable structure and a fixed structure surrounding the movable structure, a gap being present between the movable structure and the fixed structure;

and one end of the elastic beam is arranged on the side surface of the fixed structure, which faces the movable structure, and the other end of the elastic beam is a free end.

According to the MEMS device provided by the embodiment of the invention, the elastic beam structure is arranged on the side surface of the fixed structure, which faces the movable structure, so that the resetting capability of the movable structure can be improved, and the elastic beam is in friction contact in the collision to the separation process with the movable structure, so that the adhesion and locking defects of the MEMS device can be reduced, and the service life, reliability and yield of a product are further improved.

Example 1

Hereinafter, a MEMS device according to an embodiment of the present invention will be described in detail with reference to fig. 2 to 5, wherein fig. 2 shows a top view of the MEMS device according to an embodiment of the present invention; FIG. 3 illustrates a schematic partial cross-sectional view of a MEMS device in accordance with an embodiment of the present invention; FIG. 4 is a schematic view showing the structure of the fixed structure, the elastic beam and the stopper of the MEMS device according to an embodiment of the present invention; fig. 5 is a schematic diagram showing a process of collision and separation between an elastic beam and a movable structure of a MEMS device according to an embodiment of the present invention.

In one example, as shown in fig. 3, a MEMS device of an embodiment of the present invention includes a substrate 200, the substrate 200 may include at least one of the following mentioned materials: si, ge, siGe, siC, siGeC, inAs, gaAs, inP, inGaAs or other III/V compound semiconductor, or substrate 200 may also comprise silicon-on-insulator (SOI), silicon-on-insulator (SSOI), silicon-germanium-on-insulator (S-SiGeOI), silicon-germanium-on-insulator (SiGeOI), germanium-on-insulator (GeOI), or the like. Although a few examples of materials from which substrate 200 may be formed are described herein, any material that may serve as substrate 200 falls within the spirit and scope of the present invention.

In one example, as shown in fig. 2 to 4, the MEMS device of the embodiment of the present invention further includes a structural layer including a movable structure 210 and a fixed structure 220 surrounding the movable structure 210, with a gap between the movable structure 210 and the fixed structure 220. Illustratively, the fixed structure 220 serves as a frame for limiting the displacement range of the movable structure 210 and protecting the movable structure 210 during operation, so as to prevent the movable structure 210 from being displaced greatly, which would result in structural fracture of the MEMS device, and affect the device performance. Illustratively, the movable structure 210 and the fixed structure 220 may be at least one of the following mentioned materials: si, ge, siGe, siC, siGeC, inAs, gaAs, inP, inGaAs or other III/V compound semiconductors, and also includes multilayer structures and the like composed of these semiconductors. Illustratively, the movable structures include masses, and when the MEMS device is moved, the capacitance between the movable structures and the substrate changes, thereby converting the motion parameter into an electrical parameter.

As shown in fig. 3 and 4, the MEMS device according to the embodiment of the invention further includes an elastic beam 230, wherein one end of the elastic beam 230 is disposed on a side of the fixed structure 220 facing the movable structure 210, and the other end is a movable free end, i.e. a non-fixed end. Specifically, the elastic beam 230 may be formed by etching the redundant frame of the fixed structure 220, that is, the elastic beam 230 and the fixed structure 220 are integrally formed, which does not cause an increase in the overall size of the chip and the process cost.

In one example, the side of the elastic beam 230 facing the movable structure 210 may protrude from the side of the fixed structure 220 facing the movable structure 210, so that the movable structure 210 contacts the elastic beam 230 before contacting the fixed structure 220, and the elastic beam 230 is capable of deforming under the pressure of the movable structure 210, and in order to restore the original state, the elastic beam 230 may generate a pushing force to the movable structure 210 to drive the movable structure 210 to separate from the elastic beam 230, i.e. to drive the movable structure 210 to reset, thereby improving the resetting capability of the movable structure 210 and reducing the blocking and locking defects of the movable structure 210. Meanwhile, the position of the contact point of the elastic beam 230 changes in the process of colliding with the movable structure 210 until being separated, that is, the contact in the process is friction contact, so that the blocking and locking defects of the movable structure 210 can be further reduced.

Specifically, as shown in fig. 4 and 5, a gap 250 is formed between the elastic beam 230 and the fixed structure 220, and the elastic beam 230 deforms toward the gap 250 when receiving the pressure of the movable structure 210, and at this time, the elastic beam 230 generates a pushing force on the movable structure 210 to drive the movable structure 210 to return.

In one example, as shown in fig. 4, the elastic beam 230 is further provided with a stopper 240, and the stopper 240 is disposed on a side of the elastic beam 230 facing the movable structure 210. Specifically, the stop block 240 protrudes from the side surface of the elastic beam 230, so that the stop block 240 can be used as a contact point between the movable structure 210 and the elastic beam 230, as shown in fig. 5, in the process that the elastic beam 230 collides with the movable structure 210 until the movable structure is separated, the contact point between the movable structure 210 and the elastic beam 230 is always on the stop block 240, and the surface of the stop block 240 can be designed into a circular arc surface, so that the contact mode of the stop block 240 and the elastic beam 230 is point contact, thereby greatly reducing the contact area between the movable structure 210 and the elastic beam 230, and further reducing the blocking and locking defects of the movable structure 210; meanwhile, the contact generated by the stop block 240 is friction contact in the process of colliding with the movable structure 210 until the stop block is separated, so that the blocking and locking defects of the movable structure 210 can be further reduced.

In one example, as shown in fig. 2 and 4, at least one pair of elastic beams 230 is disposed on each side of the fixed structure 220 facing the movable structure 210, wherein two elastic beams 230 of each pair of elastic beams 230 are disposed opposite to each other, i.e., free ends of the two elastic beams 230 are disposed opposite to each other. Specifically, the two oppositely disposed elastic beams 230 can jointly drive the movable structure 210 to reset when the local pressure of the movable structure 210 is received, as shown in fig. 4, the two oppositely disposed elastic beams 230 can jointly form an acting force F to drive the movable structure 210 to reset, i.e. the reset capability of the local movable structure 210 can be improved, and meanwhile, the two locally oppositely disposed elastic beams 230 can jointly bear the pressure of the movable structure 210, so that the pressure resistance of the elastic beams 230 can be improved, and the stability of the structure is improved.

Illustratively, as shown in fig. 2, two pairs of elastic beams 230 may be disposed on a side of each fixed structure 220 facing the movable structure 210, and the two pairs of elastic beams 230 on each side may be respectively located near edges of the side to further improve the restoring capability of the movable structure 210. Illustratively, three or more pairs of spring beams 230 may be further provided on the side of each fixed structure 220 facing the movable structure 210, or a plurality of individual spring beams 230 may be further provided, to which the present invention is not limited.

In one example, as shown in fig. 3, the MEMS device of the embodiment of the present invention further includes an insulating layer/release layer 260, the insulating layer/release layer 260 being disposed on the substrate 200, and the fixing structure being disposed on the insulating layer/release layer 260 and being fixed on the substrate 200 through the insulating layer/release layer 260. Illustratively, the insulating layer/release layer 260 may be an inorganic insulating layer such as a silicon oxide layer, a silicon nitride layer, or a silicon oxynitride layer, or an insulating layer such as a material containing polyvinyl phenol, polyimide, or siloxane. In addition, polyvinyl phenol, polyimide, or siloxane may be effectively formed by a droplet discharge method, a printing method, or a spin coating method. Siloxanes can be classified into silica glass, alkyl siloxane polymers, alkyl silsesquioxane polymers, silsesquioxane hydride polymers, alkyl silsesquioxane hydride polymers, and the like, according to their structure. In addition, the insulating layer/release layer 260 may be formed of a material including a polymer (polysilazane) having si—n bond. Further, these films may be laminated to form an insulating layer/release layer 260.

In one example, the MEMS device of the present invention comprises a MEMS gyroscope, the movable structure 210 comprises a comb structure of the MEMS gyroscope, or the MEMS device comprises a MEMS accelerometer, and the movable structure 210 comprises a comb structure of the MEMS accelerometer. The number, size, etc. of the comb structures can be set according to the process requirements of the accelerometer and gyroscope. For example, MEMS gyroscopes may also be used in combination with MEMS accelerometers to reduce cost and volume.

In one example, as shown in fig. 2, the movable structure 210 may include a first sub-movable structure 2101, a second sub-movable structure 2102, and a third sub-movable structure 2103. Illustratively, when the MEMS device of the present invention includes a MEMS gyroscope, the movable structure 210 includes a comb structure of the MEMS gyroscope, the first sub-movable structure 2101 is used to measure angular velocity in the x-axis direction, the second sub-movable structure 2102 is used to measure angular velocity in the y-axis direction, and the third sub-movable structure 2103 is used to measure angular velocity in the z-axis direction. Illustratively, when the MEMS device of the present invention comprises a MEMS accelerometer, the movable structure 210 comprises a comb structure of the MEMS accelerometer, the first sub-movable structure 2101 is used to measure acceleration in the x-axis direction, the second sub-movable structure 2102 is used to measure acceleration in the y-axis direction, and the third sub-movable structure 2103 is used to measure acceleration in the z-axis direction.

In one example, the comb structure includes a fixed comb electrode and a movable comb electrode. Illustratively, the stationary comb-teeth electrode is fixed to the substrate 200 by an insulating layer/release layer 260.

In one example, the movable structure also includes a mass, such as a MEMS gyroscope, that moves continuously along a plane of motion, and as long as an angular velocity is applied parallel to the plane of motion, a Ke Liao force is generated perpendicular to the direction of motion of the mass, causing the mass to displace by a magnitude proportional to the magnitude of the applied angular velocity. This displacement will cause a change in capacitance between the fixed and movable comb electrodes of the mass, and therefore the angular rate applied by the input part of the gyroscope is converted into an electrical parameter that can be detected by a dedicated circuit. The working principle of the accelerometer is similar to that of a gyroscope, and the acceleration is detected according to capacitance change generated by displacement of a mass block.

The description of the structure of the MEMS device according to the embodiment of the present invention is completed, and the complete MEMS device may further include other constituent structures, which are not described herein in detail.

Because the elastic beam structure is arranged on the side face, facing the movable structure, of the fixed structure, the resetting capability of the movable structure can be improved, and the elastic beam is in friction contact in the collision to separation process with the movable structure, so that the adhesion and locking defects of the MEMS device can be reduced, and the service life, reliability and yield of products are improved. Illustratively, a stopper is further disposed on a side of the elastic beam facing the movable structure, and the stopper can reduce a contact area between the elastic beam and the movable structure, thereby further reducing blocking and locking defects of the MEMS device.

Example two

In another embodiment of the present invention, an electronic apparatus is provided, including the MEMS device described above.

The electronic device of this embodiment may be any electronic product or apparatus such as a mobile phone, a tablet computer, a notebook computer, a netbook, a game console, a television, a VCD, a DVD, a navigator, a camera, a video camera, a recording pen, an MP3, an MP4, and a PSP, and may also be any intermediate product including the MEMS device. The electronic device provided by the embodiment of the invention has better performance due to the adoption of the MEMS device.

Although a number of embodiments have been described herein, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various modifications and alterations may be made in the arrangement and/or component parts of the subject matter within the scope of the disclosure, the drawings, and the appended claims. In addition to modifications and variations in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims (10)

1. A MEMS device, comprising:

a substrate;

a structural layer on the substrate, the structural layer comprising a movable structure and a fixed structure surrounding the movable structure, a gap being present between the movable structure and the fixed structure;

and one end of the elastic beam is arranged on the side surface of the fixed structure, which faces the movable structure, and the other end of the elastic beam is a free end.

2. The MEMS device of claim 1, further comprising a stop disposed on a side of the spring beam that faces the movable structure.

3. The MEMS device, as recited in claim 2, wherein the surface of the stop block is rounded.

4. The MEMS device, as recited in claim 1, wherein a gap is formed between the spring beam and the fixed structure, the spring beam deforming toward the gap when subjected to pressure by the movable structure.

5. The MEMS device, as recited in claim 1, wherein at least one pair of spring beams is disposed on each side of the fixed structure facing the movable structure, the free ends of two spring beams of each pair of the at least one pair of spring beams being disposed opposite each other.

6. The MEMS device of claim 1, wherein the MEMS device comprises a MEMS gyroscope, the movable structure comprises a comb structure of the MEMS gyroscope, or the MEMS device comprises a MEMS accelerometer, the movable structure comprises a comb structure of the MEMS accelerometer.

7. The MEMS device of claim 6, wherein when the MEMS device comprises a MEMS gyroscope, the movable structure comprises a comb structure of the MEMS gyroscope, the movable structure comprises a first sub-movable structure, a second sub-movable structure, and a third sub-movable structure, wherein:

the first movable sub-structure is used for measuring the angular velocity in the x-axis direction;

the second movable sub-structure is used for measuring the angular velocity in the y-axis direction;

the third sub-movable structure is used for measuring the angular velocity in the z-axis direction.

8. The MEMS device of claim 6, wherein when the MEMS device comprises a MEMS accelerometer, the movable structure comprises a comb structure of the MEMS accelerometer, the movable structure comprises a first sub-movable structure, a second sub-movable structure, and a third sub-movable structure, wherein:

the first movable sub-structure is used for measuring acceleration in the x-axis direction;

the second movable sub-structure is used for measuring acceleration in the y-axis direction;

the third sub-movable structure is used for measuring acceleration in the z-axis direction.

9. The MEMS device of claim 6, wherein the comb structures comprise fixed comb electrodes and movable comb electrodes.

10. An electronic device, characterized in that it comprises a MEMS device as claimed in any one of claims 1-9.