Multilayer structure of MEMS actuator and preparation method thereof
By adopting a concave-convex and convex coupling connection and through-hole embedding structure in the multi-layer structure of the MEMS actuator, the problem of sliding and disengagement of the metal layer under the action of shear force is solved, and the connection strength and mechanical properties of the device are significantly improved.
Patent Information
- Application Number
- CN202311107581.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-30
- Publication Date
- 2025-02-28
AI Technical Summary
The multi-layer structure of the MEMS actuator can easily cause the metal layer to slip and break away from the substrate under the action of shear force, resulting in device damage.
The insulating layer and the metal layer are connected in the multi-layer structure by a concave-convex coupling method, and through holes are opened on the insulating layer if necessary, and the protrusions of the metal layer are embedded in the through holes to enhance the connection strength.
The connection strength between the insulating layer and the metal layer is effectively enhanced, and the metal layer is prevented from sliding away from the substrate under the action of shear force, improving the mechanical properties and reliability of the device.
Smart Images
Figure CN119528081A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of micro-electromechanical systems, and in particular, relates to a multi-layer structure of a MEMS actuator and a preparation method thereof. Background Art
[0002] Micro-Electro-Mechanical System (MEMS), also known as micro-electromechanical system, refers to a tiny device with a size of several millimeters or even smaller. Its internal structure is generally in the micrometer or even nanometer level. It is an independent intelligent system. MEMS devices are mainly divided into two categories: sensors and actuators. Sensors are devices used to detect and detect physical, chemical, biological and other phenomena and signals, while actuators are devices used to achieve mechanical motion, force and torque. An ideal actuator needs to have high mechanical efficiency, be able to produce high-speed motion, have a high energy-to-mass ratio, and have strong adaptability to environmental conditions and be able to resist various environmental interferences such as thermal expansion and vibration.
[0003] MEMS actuators include multiple movable parts. The movable parts usually have a multilayer structure in which the metal layer and the substrate are connected by an insulating film such as silicon dioxide. As shown in the figure, the multilayer structure includes a substrate, an insulating layer and a metal layer stacked in sequence. The actions to be performed by the movable parts usually include twisting and stretching, which will generate pressure, tension, shear force, etc. in different directions, which puts higher requirements on the interlayer bonding strength of the multilayer structure. Among them, the shear force in the parallel direction of the multilayer structure can easily cause relative slippage of each film layer, such as causing the metal layer to slip, thereby causing the metal layer to fall off and damage the device. In addition, most actuators need to operate for a long time under harsh conditions such as high temperature, high humidity, and temperature cycling. Due to the mismatch of thermal expansion coefficients between different metals and insulating materials, different thermal stresses, and different expansion degrees of materials, structural deformation and even stratification occur, resulting in a decrease in the connection strength between the metal layer and the insulating layer on the substrate, and the metal layer is separated from the substrate, which ultimately causes the actuator to fail to work. Summary of the invention
[0004] The technical problem solved by the present invention is: how to strengthen the bonding strength between film layers of the multi-layer structure of the MEMS actuator.
[0005] The present application discloses a multilayer structure of a MEMS actuator, wherein the multilayer structure comprises a substrate, an insulating layer and a metal layer which are stacked in sequence, and the insulating layer and the metal layer are connected in a concave-convex manner along the stacking direction.
[0006] Optionally, the insulating layer is provided with a plurality of through holes along the direction of the stacking, and the surface of the metal layer facing the substrate has protrusions, and the protrusions are embedded in the through holes.
[0007] Optionally, the multi-layer structure further includes a metal fixing layer, wherein the metal fixing layer is located between the substrate and the insulating layer, and the metal fixing layer is fixedly connected to the substrate and the protrusion respectively.
[0008] Optionally, a partial area of the surface of the insulating layer facing the substrate is recessed to form a groove, the groove is communicated with the through hole, and a portion of the metal fixing layer is embedded in the groove and fixedly connected to the protrusion.
[0009] Optionally, a portion of the metal fixing layer is embedded in the through hole and fixedly connected to the protrusion.
[0010] The present application also discloses a method for preparing a multilayer structure of a MEMS actuator, the method comprising:
[0011] An insulating layer is prepared on a substrate;
[0012] A metal layer is prepared on the insulating layer, wherein the insulating layer and the metal layer are connected with each other in a concave-convex manner.
[0013] Optionally, the preparation method further comprises:
[0014] After the insulating layer is prepared, a plurality of through holes are formed on the insulating layer;
[0015] When a metal layer is prepared on the insulating layer, a portion of the metal layer is embedded in the through hole.
[0016] Optionally, the preparation method further comprises:
[0017] Before preparing the insulating layer on the substrate, preparing a metal fixing layer on the substrate, wherein the metal fixing layer is located between the substrate and the insulating layer;
[0018] When preparing the metal layer, a portion of the metal layer is embedded in the through hole and deposited on the metal fixing layer.
[0019] Optionally, the preparation method further comprises:
[0020] When the insulating layer is prepared on the substrate, the insulating layer completely covers the metal fixing layer and the portion of the insulating layer exceeding the metal fixing layer covers the substrate, so that a portion of the metal fixing layer is embedded in the insulating layer.
[0021] Optionally, the metal fixing layer has a convex structure on a surface facing away from the substrate, and the convex structure is embedded in the through hole, and the preparation method further includes:
[0022] When preparing the metal layer, a portion of the metal layer is embedded in the through hole and deposited on the convex structure.
[0023] The multilayer structure of a MEMS actuator and a preparation method thereof disclosed in the present invention have the following technical effects:
[0024] The multilayer structure uses a concave-convex connection method to enhance the connection strength between the insulating layer and the metal layer. At the same time, it can further utilize the bonding force between metal and metal to enhance the bonding strength between the metal layer and the substrate, and prevent the metal layer from slipping and detaching from the substrate under the action of shear force. The preparation process of this method is convenient and feasible, does not require additional process steps, and can be efficiently embedded in the MEMS actuator preparation process. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 is a cross-sectional schematic diagram of a multilayer structure of a MEMS actuator according to Embodiment 1 of the present invention;
[0026] Figure 2 is another cross-sectional schematic diagram of the multilayer structure of the MEMS actuator according to the first embodiment of the present invention;
[0027] Figure 3 is another cross-sectional schematic diagram of the multilayer structure of the MEMS actuator according to the first embodiment of the present invention;
[0028] Figure 4A , Figure 4B , Figure 4C Schematic diagram of the preparation process of the multilayer structure of the MEMS actuator according to the second embodiment of the present invention. DETAILED DESCRIPTION
[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0030] Before describing the various embodiments of the present application in detail, the technical concept of the present application is briefly described first: the multi-layer structure of the movable part of the MEMS actuator usually includes a laminated insulating layer and a metal layer. The shear force generated by the movable part during the execution of the action easily causes the metal layer to slip from the insulating layer and fall off, damaging the device. To this end, the multi-layer structure of the MEMS actuator provided by the present application makes the insulating layer and the metal layer connected in a concave-convex manner along the direction of the stacking. On the one hand, the connection strength between the metal layer and the insulating layer is strengthened. On the other hand, the concave-convex matching method makes the metal layer and the insulating layer produce a mutual bite effect, preventing the shear force from causing relative slippage and falling off between the metal layer and the insulating layer, thereby avoiding damage to the device.
[0031] Specifically, Figure 1 As shown, the multilayer structure of the MEMS actuator of the first embodiment includes a substrate 100, an insulating layer 200 and a metal layer 300 which are stacked in sequence, and the insulating layer 200 and the metal layer 300 are connected in a concave-convex manner along the stacking direction.
[0032] In one embodiment, the insulating layer 200 is provided with a plurality of through holes 201 along the direction of the stacking, and the metal layer 300 has a protrusion 301 on the surface facing the substrate 100, and the protrusion 301 is embedded in the through hole 201. Through the matching connection between the protrusion 301 and the through hole 201, on the one hand, the connection strength between the insulating layer 200 and the metal layer 300 in the stacking direction is strengthened, and on the other hand, the contact area between the insulating layer 200 and the metal layer 300 in the vertical direction of the stacking direction is increased, that is, the connection strength between the insulating layer 200 and the metal layer 300 in the vertical direction is strengthened, and the shear force is prevented from causing the metal layer 300 to slip and separate from the insulating layer 200 and the substrate 100. In other embodiments, the positions of the through hole 201 and the protrusion 301 can be interchanged, that is, the through hole can be provided on the metal layer, and the protrusion can be provided on the insulating layer, so as to realize the concave-convex matching connection between the insulating layer 200 and the metal layer 300. It should be noted that the direction along the stacking direction includes a direction completely parallel to the stacking direction and an inclined direction with an angle deviation from the stacking direction. The angle deviation can be set according to actual needs. For example, the angle deviation can be 1 degree, 2 degrees..., and the angle deviation does not exceed 30 degrees.
[0033] Furthermore, in one embodiment, the protrusion 301 is embedded in the through hole 201 and a portion of the protrusion 301 passes through the through hole 201 to be connected to the substrate 100 , so as to increase the connection strength between the metal layer 300 and the substrate 100 .
[0034] For example, Figure 2 As shown, in order to further strengthen the connection strength between the metal layer 300 and the substrate 100 and the insulating layer 200, the multilayer structure also includes a metal fixing layer 400, which is located between the substrate 100 and the insulating layer 200, and the metal fixing layer 400 is fixedly connected to the substrate 100 and the protrusion 301, that is, the protrusion 301 passes through the insulating layer 200 and is connected to the metal fixing layer 400, and the connection strength between the metal layer 300 and the substrate 100 can be further strengthened by the bonding force between metal and metal. At the same time, due to the similar fatigue characteristics and thermal expansion coefficients between metals, the thermal stress of the movable parts during the operation of high temperature and high humidity is reduced, thereby reducing the occurrence of failure situations such as deformation and delamination. Exemplarily, the metal fixing layer 400 preferably uses a metal material with a lattice size similar to that of the metal layer 300 to reduce the lattice mismatch problem.
[0035] In one embodiment, a portion of the surface of the insulating layer 200 facing the substrate is recessed to form a groove 202, the groove 202 is connected to the through hole 201, and a portion of the metal fixing layer 400 is embedded in the groove 202 and fixedly connected to the protrusion 301. On the one hand, the connection strength between the metal fixing layer 400 and the insulating layer 200 can be enhanced, and on the other hand, the metal fixing layer 400 and the insulating layer 200 can be overlapped in the stacking direction, thereby reducing the overall thickness of the multilayer structure.
[0036] In another embodiment, if Figure 3 As shown, a portion of the metal fixing layer 400 is embedded in the through hole 201 and fixedly connected to the protrusion 301. Exemplarily, a convex structure 401 is formed on the surface of the metal fixing layer 400 facing away from the substrate 100, and the convex structure 401 is embedded in the through hole 201 and fixedly connected to the protrusion 301, so that the connection strength between the metal fixing layer 400 and the insulating layer 200 can be further strengthened.
[0037] The multilayer structure of the MEMS actuator disclosed in the first embodiment of the present invention adopts a concave-convex fitting connection method to enhance the connection strength between the insulating layer and the metal layer. At the same time, it can further utilize the bonding force between metal and metal to enhance the bonding strength between the metal layer and the substrate, thereby preventing the metal layer from slipping and detaching from the substrate under the action of shear force.
[0038] The second embodiment also discloses a method for preparing a multilayer structure of a MEMS actuator, the method comprising:
[0039] Step S10, preparing an insulating layer 200 on the substrate 100;
[0040] Step S20, preparing a metal layer 300 on the insulating layer 200, wherein the insulating layer and the metal layer are connected with each other in a concave-convex manner.
[0041] For example, the substrate 100 may be a silicon substrate, the insulating layer 200 may be silicon dioxide, the insulating layer 200 may be prepared on the substrate 100 by a deposition process, and the metal layer 300 may be prepared on the insulating layer 200 by a sputtering process or an electroplating process.
[0042] In one embodiment, after the insulating layer 200 is prepared in step S10, a plurality of through holes 201 are formed on the insulating layer 200. For example, an etching process can be used to form the through holes 201 in the insulating layer 200. Further, when the metal layer 300 is prepared on the insulating layer 200 having the through holes 201 in step S20, a portion of the metal layer 300 is embedded in the through holes 201 to form protrusions 301, thereby increasing the connection strength between the metal layer 300 and the insulating layer 200.
[0043] In another embodiment, if Figure 4A and Figure 4B As shown, in step S10, before preparing the insulating layer 200 on the substrate 100, a metal fixing layer 400 is prepared on the substrate 100, and then the insulating layer 200 is prepared. The metal fixing layer 400 is located between the substrate 100 and the insulating layer 200. Further, Figure 4C As shown, in step S20 , when preparing the metal layer 300 , a portion of the metal layer 300 is embedded in the through hole 201 and deposited on the metal fixing layer 400 , that is, the protrusion 301 of the metal layer 300 passes through the through hole 201 and is connected to the metal fixing layer 400 .
[0044] Furthermore, when the insulating layer 200 is prepared on the substrate 100 in step S10, the insulating layer 200 completely covers the metal fixing layer 400 and the portion of the insulating layer 200 that exceeds the metal fixing layer 400 covers the substrate 100, so that a portion of the metal fixing layer 400 is embedded in the insulating layer 200. On the one hand, the connection strength between the metal fixing layer 400 and the insulating layer 200 can be enhanced, and on the other hand, the metal fixing layer 400 and the insulating layer 200 can be overlapped in the stacking direction, thereby reducing the overall thickness of the multilayer structure.
[0045] In one embodiment, the prepared metal fixing layer 400 has a convex structure 401 on the surface facing away from the substrate 100, and a through hole 201 is opened on the insulating layer 200 at a position opposite to the convex structure 401 so that the convex structure 401 is embedded in the through hole 201. In step S20, when preparing the metal layer 300, a portion of the metal layer 300 is embedded in the through hole 201 and deposited on the convex structure 401.
[0046] The method for preparing the multilayer structure of the MEMS actuator disclosed in the second embodiment has a convenient and feasible preparation process, does not require additional process steps, and can be efficiently embedded in the MEMS actuator preparation process.
[0047] This embodiment 1 also discloses a MEMS actuator, which includes the multilayer structure of the MEMS actuator in the embodiment 1, and the MEMS actuator can prevent the metal layer from slipping relative to the substrate and falling off the substrate during the execution of the action. It should be noted that it is understandable that a complete MEMS actuator should also have other necessary basic components, but other components are not the focus of this embodiment, so they are not shown in the figure and are not described in detail in the specification, and these components are well-known technologies for those skilled in the art.
[0048] The specific implementation methods of the present invention are described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that these embodiments can be modified and improved without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents. These modifications and improvements should also be within the scope of protection of the present invention.
Claims
1. A multilayer structure of a MEMS actuator, characterized in that: The multilayer structure comprises a substrate, an insulating layer and a metal layer which are stacked in sequence, and the insulating layer and the metal layer are connected in a concave-convex manner along the stacking direction.
2. The multilayer structure of the MEMS actuator according to claim 1, characterized in that: The insulating layer is provided with a plurality of through holes along the direction of the stacking, and the metal layer has protrusions on the surface facing the substrate, and the protrusions are embedded in the through holes.
3. The multilayer structure of the MEMS actuator according to claim 2, characterized in that: The multi-layer structure further comprises a metal fixing layer, wherein the metal fixing layer is located between the substrate and the insulating layer, and the metal fixing layer is fixedly connected to the substrate and the protrusion respectively.
4. The multilayer structure of the MEMS actuator according to claim 3, characterized in that: A partial area of the surface of the insulating layer facing the substrate is recessed to form a groove, the groove is communicated with the through hole, and a part of the metal fixing layer is embedded in the groove and fixedly connected to the protrusion.
5. The multilayer structure of the MEMS actuator according to claim 3, characterized in that: A portion of the metal fixing layer is embedded in the through hole and fixedly connected to the protrusion.
6. A method for preparing a multilayer structure of a MEMS actuator, characterized in that: The preparation method comprises: An insulating layer is prepared on a substrate; A metal layer is prepared on the insulating layer, wherein the insulating layer and the metal layer are connected with each other in a concave-convex manner.
7. The preparation method according to claim 6, characterized in that: The preparation method further comprises: After the insulating layer is prepared, a plurality of through holes are formed on the insulating layer; When a metal layer is prepared on the insulating layer, a portion of the metal layer is embedded in the through hole.
8. The preparation method according to claim 7, characterized in that: The preparation method further comprises: Before preparing the insulating layer on the substrate, preparing a metal fixing layer on the substrate, wherein the metal fixing layer is located between the substrate and the insulating layer; When preparing the metal layer, a portion of the metal layer is embedded in the through hole and deposited on the metal fixing layer.
9. The preparation method according to claim 8, characterized in that: The preparation method further comprises: When the insulating layer is prepared on the substrate, the insulating layer completely covers the metal fixing layer and the portion of the insulating layer exceeding the metal fixing layer covers the substrate, so that a portion of the metal fixing layer is embedded in the insulating layer.
10. The preparation method according to claim 8, characterized in that: The metal fixing layer has a convex structure on a surface facing away from the substrate, and the convex structure is embedded in the through hole. The preparation method further includes: When preparing the metal layer, a portion of the metal layer is embedded in the through hole and deposited on the convex structure.