Traveling wave microactuator structure with displacement amplification teeth, preparation method and micromotor

Abstract

The present invention discloses a traveling wave microactuator structure with displacement amplification teeth, a preparation method and a micromotor, and relates to the technical field of traveling wave microactuators. The key points of the technical solution are: comprising a PZT layer, a top silicon structure layer and a plurality of stator teeth arranged in sequence; the plurality of stator teeth are arranged in a circular distribution on the side of the top silicon structure layer facing away from the PZT layer, and adjacent stator teeth are arranged at intervals. On the one hand, the stator teeth are prepared using the back silicon support layer in the PZT-SOI sheet; on the other hand, the preparation of the traveling wave microactuator structure is achieved by bonding two PZT-SOI sheets. The present invention combines the MEMS process with the original PZT structure to effectively solve the friction and wear problems of the PZT film, and can also improve the output torque.

Description

Technical Field

[0001] The present invention relates to the technical field of traveling wave micro-actuators, and more specifically, to a traveling wave micro-actuator structure with displacement amplifying teeth, a preparation method and a micro-motor. Background Art

[0002] MEMS piezoelectric actuators have the advantages of small size, light weight, easy integration with the base structure, low price, and displacement generated by the solid crystallization effect of the material. They have high displacement resolution, large output force, large load bearing capacity, fast response speed, and large instantaneous acceleration. They have received widespread attention and can provide micromotors with high-resolution positioning, high-dynamic motion characteristics and other requirements.

[0003] The traveling wave microactuator structure in the prior art is made of PZT-SOI wafers, such as Figure 1 As shown, the PZT-SOI sheet includes a back silicon support layer, a top silicon structure layer and a PZT layer arranged in sequence from bottom to top. However, the structural design and process implementation of the conventional traveling wave microactuator is to first etch the PZT layer and the top silicon structure layer as the driving structure layer, and then etch the back silicon support layer as the supporting structure after release. When the traveling wave driven particle is performing elliptical motion, the displacement component of the particle in the circumferential direction is small, resulting in a relatively low conversion efficiency of the drive, and the PZT film layer directly contacts the rotor, which will cause friction and wear, making the PZT film easily worn, thereby causing the driver to fail; in addition, due to the limited thickness of the driving structure layer of the conventionally designed PZT film traveling wave micromotor, the limited output torque of the micromotor is constrained to a certain extent, and it is difficult to integrate other materials to form displacement amplification teeth in the MEMS process.

[0004] Therefore, how to study and design a traveling wave microactuator structure with displacement amplification teeth, a preparation method and a micromotor that can overcome the above-mentioned defects is a problem that we urgently need to solve. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide a traveling wave microactuator structure with displacement amplification teeth, a preparation method and a micromotor, which effectively solves the friction and wear problems of the PZT film on the basis of the original PZT structure by combining MEMS technology and can improve the output torque.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] In a first aspect, a traveling wave microactuator structure with displacement amplification teeth is provided, comprising a PZT layer, a top silicon structure layer, and a plurality of stator teeth arranged in sequence;

[0008] The plurality of stator teeth are arranged in a circumferential distribution manner on the side of the top silicon structure layer facing away from the PZT layer, and adjacent stator teeth are spaced apart.

[0009] Preferably, the thickness of the stator teeth is 100um-120um.

[0010] Preferably, the thickness of the stator teeth is 110 um.

[0011] Preferably, the inner diameter of the stator teeth is 1200-1300 um.

[0012] Preferably, the inner diameter of the stator teeth is 1250 um.

[0013] Preferably, the thickness of the PZT layer is 5 um.

[0014] Preferably, the thickness of the top silicon structure layer is 25 um.

[0015] In a second aspect, a method for preparing the traveling wave microactuator structure with displacement amplification teeth as described in the first aspect is provided, comprising the following steps:

[0016] S1: Etching the PZT layer and the top silicon structure layer in the PZT-SOI wafer;

[0017] S2: Thinning the thickness of the back silicon support layer in the PZT-SOI wafer to the designed thickness;

[0018] S3: DRIE etching of the back silicon support layer forms a displacement amplification tooth structure to obtain a traveling wave microactuator structure.

[0019] In a third aspect, a method for preparing the traveling wave microactuator structure with displacement amplification teeth as described in the first aspect is provided, comprising the following steps:

[0020] S11: patterning a PZT layer in a PZT-SOI wafer and etching a back silicon support layer;

[0021] S21: making a tooth structure pattern on the top silicon structure layer in another PZT-SOI wafer;

[0022] S31: bonding the two PZT-SOI sheets in S11 and S21 in a way that the PZT layers face each other;

[0023] S41: After bonding is completed, the back silicon support layer of the tooth structure in S21 is removed;

[0024] S51: Etching the top silicon structure layer in S11 to release the traveling wave microactuator structure.

[0025] In a fourth aspect, a micro motor is provided, comprising a rotor and a traveling wave micro actuator structure with displacement amplification teeth as described in the first aspect.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The traveling wave microactuator structure with displacement amplification teeth proposed in the present invention, combined with MEMS technology on the basis of the original PZT structure, effectively solves the friction and wear problem of the PZT film;

[0028] 2. The present invention realizes the preparation of the traveling wave microactuator structure from two ways, the front side and the back side of the PZT-SOI sheet. On the one hand, the stator teeth are prepared by using the back silicon support layer in the PZT-SOI sheet; on the other hand, the traveling wave microactuator structure is prepared by bonding two PZT-SOI sheets; while effectively solving the friction and wear problem of the PZT film, the output torque can be improved;

[0029] 3. The present invention realizes the design of displacement amplification teeth with a thickness several times the thickness of the structural layer through the bulk silicon process, thereby realizing the preparation of high-thickness displacement amplification tooth structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0031] Figure 1 It is a schematic diagram of the structure of a PZT-SOI sheet in the prior art;

[0032] Figure 2 It is a schematic diagram of the overall structure of Example 1 of the present invention;

[0033] Figure 3 is a schematic diagram of the preparation in Example 2 of the present invention;

[0034] Figure 4 is a schematic diagram of the preparation in Example 3 of the present invention;

[0035] Figure 5 Schematic diagram of modal effect in Embodiment 4 of the present invention, a is a schematic diagram of modal structure, b is a model diagram;

[0036] Figure 6 is a simulation schematic diagram of tooth height parameters in Example 4 of the present invention;

[0037] Figure 7 Schematic diagram of simulation of tooth inner diameter parameters in Example 4 of the present invention, a is a line drawing of the stator tooth surface, and b is a displacement diagram of the stator tooth surface morphology.

[0038] Marks and corresponding parts names in the attached drawings:

[0039] 1. PZT layer; 2. Top silicon structure layer; 3. Back silicon support layer; 4. Rotor; 5. Stator teeth. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0041] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to the other component.

[0042] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0044] Embodiment 1: A traveling wave microactuator structure with displacement amplification teeth, such as Figure 2 As shown, it includes a PZT layer 1, a top silicon structure layer 2 and a plurality of stator teeth 5 arranged in sequence. The plurality of stator teeth 5 are arranged in a circumferential distribution manner on the side of the top silicon structure layer 2 facing away from the PZT layer 1, and adjacent stator teeth 5 are arranged at intervals.

[0045] In this embodiment, the thickness of the stator tooth 5 is 100um-120um. The inner diameter of the stator tooth 5 is 1200-1300um. The thickness of the PZT layer 1 is 5um. The thickness of the top silicon structure layer 2 is 25um.

[0046] In addition, the number of teeth is a modal multiple and is evenly distributed around the circumference; the outer diameter of stator tooth 5 is equivalent to the piezoelectric layer - maximum output torque; the ratio of tooth width to tooth slot width is 2:1; the tooth height is related to the structural size and resonant frequency and has an optimal value.

[0047] Embodiment 2: A method for preparing a traveling wave microactuator structure with displacement amplification teeth, such as Figure 3 As shown, the following steps are included:

[0048] S1: Etching the PZT layer 1 and the top silicon structure layer 2 in the PZT-SOI wafer;

[0049] S2: thinning the thickness of the back silicon support layer 3 in the PZT-SOI wafer to the designed thickness;

[0050] S3: DRIE etching the back silicon support layer 3 to form a displacement amplification tooth structure, thereby obtaining a traveling wave microactuator structure.

[0051] Embodiment 3: A method for preparing a traveling wave microactuator structure with displacement amplification teeth, such as Figure 4 As shown, the following steps are included:

[0052] S11: patterning a PZT layer 1 in a PZT-SOI wafer and etching a back silicon support layer 3;

[0053] S21: forming a tooth structure pattern on the top silicon structure layer 2 in another PZT-SOI wafer;

[0054] S31: bonding the two PZT-SOI sheets in S11 and S21 in a manner that the PZT layer 1 faces each other;

[0055] S41: After bonding is completed, the back silicon support layer 3 of the tooth structure in S21 is removed;

[0056] S51: etching the top silicon structure layer 2 in S11 to release the traveling wave microactuator structure.

[0057] In addition, the present invention can also use photoresist, such as SU8 glue, to realize the displacement amplification tooth structure on the stator structure of the microactuator through photolithography; directly realize the growth of the displacement amplification tooth structure on the stator structure of the traveling wave microactuator through additive manufacturing methods such as 3D printing or electroplating; and bond a silicon wafer to the front side of the PZT-SOI wafer, then thin it, and finally etch the displacement amplification teeth.

[0058] Example 4: Taking the traveling wave microactuator with displacement amplification tooth structure based on B13 as an example, the modes designed for the PZT traveling wave microactuator can be B13, B14, B15, and B16 modes. Figure 5 As shown, Figure 5 In the figure, a is the modal schematic structure and b is the model diagram.

[0059] According to the design principle, the number of teeth is determined to be the modal multiple, and the outer diameter of stator tooth 5 is the outer diameter of the piezoelectric area to ensure the maximum output torque. The parameters of tooth height and tooth inner diameter are optimized. The COMSOL simulation results are as follows: Figure 6 and Figure 7 shown.

[0060] When the tooth height is 110um, there is an optimal value. When the tooth height increases from 50um, the tangential velocity will continue to increase, but after 110um, the drive modal resonance frequency will drop sharply, resulting in a decrease in the tangential velocity. Therefore, 110um is the optimal design parameter for the tooth height. Figure 7 In the figure, a is the line drawing of the stator tooth surface, and b is the displacement diagram of the stator tooth surface morphology. When the inner diameter of the tooth is 1250um, the deformation on the tooth surface tends to be smooth, which can provide the maximum contact area with the rotor 4, and therefore is the optimal parameter.

[0061] Working principle: Aiming at the demand for improving the torque of microactuators, the present invention designs the displacement amplifying teeth structure of microactuators, and solves the friction and wear problem of PZT layer 1 on the basis of improving the output torque; the process scheme design of high-thickness displacement amplifying teeth is completed based on the bulk silicon MEMS process. The MEMS process scheme proposed by the present invention can realize a high-thickness displacement amplifying teeth structure, and the thickness of the displacement amplifying teeth is equivalent to the thickness of the PZT-SOI structure layer. According to the working mode and specific structural form of the actual device, the thickness of the amplifying teeth can also be several times the thickness of the PZT-SOI structure layer.

[0062] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The traveling wave microactuator structure with displacement amplification teeth is characterized by: It comprises a PZT layer (1), a top silicon structure layer (2) and a plurality of stator teeth (5) which are arranged in sequence; The plurality of stator teeth (5) are arranged in a circumferential distribution manner on the side of the top silicon structure layer (2) facing away from the PZT layer (1), and adjacent stator teeth (5) are arranged at intervals.

2. The traveling wave microactuator structure with displacement amplification teeth according to claim 1 is characterized in that: The thickness of the stator teeth (5) is 100um-120um.

3. The traveling wave microactuator structure with displacement amplification teeth according to claim 2 is characterized in that: The thickness of the stator teeth (5) is 110 um.

4. The traveling wave microactuator structure with displacement amplification teeth according to claim 1 is characterized in that: The inner diameter of the stator teeth (5) is 1200-1300 um.

5. The traveling wave microactuator structure with displacement amplification teeth according to claim 4 is characterized in that: The inner diameter of the stator teeth (5) is 1250 um.

6. The traveling wave microactuator structure with displacement amplification teeth according to any one of claims 1 to 5, characterized in that: The thickness of the PZT layer (1) is 5 um.

7. The traveling wave microactuator structure with displacement amplification teeth according to any one of claims 1 to 5, characterized in that: The thickness of the top silicon structure layer (2) is 25 um.

8. The method for preparing a traveling wave microactuator structure with displacement amplification teeth according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: etching the PZT layer (1) and the top silicon structure layer (2) in the PZT-SOI wafer; S2: thinning the thickness of the back silicon support layer (3) in the PZT-SOI wafer to a designed thickness; S3: DRIE etching the back silicon support layer (3) to form a displacement amplification tooth structure, thereby obtaining a traveling wave microactuator structure.

9. The method for preparing a traveling wave microactuator structure with displacement amplification teeth according to any one of claims 1 to 7, characterized in that: The following steps are involved: S11: patterning a PZT layer (1) in a PZT-SOI wafer and etching a back silicon support layer (3); S21: forming a tooth structure pattern on the top silicon structure layer (2) in another PZT-SOI wafer; S31: bonding the two PZT-SOI sheets in S11 and S21 in a way that the PZT layers (1) face each other; S41: After bonding is completed, remove the back silicon support layer (3) of the tooth structure in S21; S51: Etching the top silicon structure layer (2) in S11 to release the traveling wave microactuator structure.

10. A micro motor, characterized in that: It comprises a rotor (4) and a traveling wave microactuator structure with displacement amplification teeth as claimed in any one of claims 1 to 7.

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