Preparation method of miniature magnetoelectric composite device
Through CMP process and ion beam etching and other technologies, the problems of piezoelectric material thinning and surface flatness in the preparation of micro magnetoelectric composite devices were solved, and high precision and consistency of devices at high frequencies were achieved, reducing costs and improving the yield rate.
Patent Information
- Application Number
- CN202510892978.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-30
- Publication Date
- 2025-09-19
AI Technical Summary
In the prior art, when preparing micro magnetoelectric composite devices, piezoelectric materials are difficult to thin and have low surface flatness, resulting in poor coupling effect, low process consistency and yield, and high cost.
The CMP process combined with chemical etching and mechanical grinding is used to thin the piezoelectric material layer, the electrode layer is deposited by electron beam evaporation, the coupling layer is spin-coated and the magnetostrictive layer is bonded, and independent magnetoelectric composite units are formed using ion beam etching. These units are then cut and pasted on a flexible circuit board to finally form a micro magnetoelectric composite device.
It achieves material thinning and surface flatness under high-frequency conditions, ensures high precision and consistency of devices, improves preparation efficiency, reduces costs and increases yield.
Smart Images
Figure CN120676850A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electronic device manufacturing, and in particular to a method for preparing a micro magnetoelectric composite device. Background Art
[0002] Magnetoelectric composite devices, combining the advantages of magnetostrictive and piezoelectric materials, offer high magnetic field detection sensitivity, leading to increasing demand in current, underwater acoustics, and sensitive magnetic detection. Currently, multi-push-pull structures offer the highest magnetoelectric conversion sensitivity, but their primary fabrication method requires manual bonding of piezoelectric units. When devices require higher frequencies and smaller sizes, piezoelectric materials present challenges such as difficulty in thinning, poor surface flatness, and poor coupling. Furthermore, manual processing leads to poor process consistency, high costs, and low yields. Summary of the Invention
[0003] In view of the above-mentioned prior art, the present invention provides a method for preparing a micro magnetoelectric composite device, which mainly solves the technical problems existing in the above-mentioned background technology.
[0004] To achieve the above-mentioned objectives, the technical solution of an embodiment of the present invention is implemented as follows: a method for preparing a micro-magnetoelectric composite device, the method comprising: thinning a piezoelectric material layer to achieve a preset thickness and flatness requirements, depositing electrode layers of the same thickness on both sides of the piezoelectric material layer through a thin film deposition process, spin-coating a coupling layer on the electrode layers on both sides, and adhering a magnetostrictive layer on the coupling layer to form a magnetoelectric composite structure, ion-etching the formed magnetoelectric composite structure to form a plurality of magnetoelectric composite units, cutting the plurality of magnetoelectric composite units and pasting them separately on a flexible circuit board to obtain a micro-magnetoelectric composite device.
[0005] Optionally, the thinning process of the piezoelectric material layer specifically includes: using a CMP process to remove uneven surface materials by combining chemical etching and mechanical grinding to achieve surface flatness.
[0006] Optionally, the grinding solids used in the chemical mechanical polishing process include silicon dioxide and ceria.
[0007] Optionally, the thin film deposition process is an electron beam evaporation process, the material of the electrode layer is gold, and the thickness of the electrode layer is 2 μm.
[0008] Optionally, the coupling layer material is epoxy resin, and the thickness of the coupling layer is 0.5 μm.
[0009] Optionally, the magnetostrictive layer is an amorphous alloy film, and the bonding process is achieved by electrostatic adsorption under dust-free conditions.
[0010] Optionally, the formed magnetoelectric composite structure is ion-etched to form a plurality of magnetoelectric composite units, specifically comprising: selectively removing the material in the target area by controlling the energy beam scanning trajectory of the ion beam until penetrating the magnetostrictive layer, the coupling layer, the electrode layer and part of the piezoelectric material layer, so as to obtain a plurality of independent magnetoelectric composite units arranged at intervals and a temporary fixing area connected to the periphery thereof.
[0011] Optionally, multiple magnetoelectric composite units are cut and then pasted on a flexible circuit board respectively, specifically comprising: cutting the multiple independent magnetoelectric composite units and the temporary fixing areas connected to their peripheries along a preset cutting path, wherein the preset cutting path is located between adjacent magnetoelectric composite units and avoids the temporary fixing areas, so that the relative sides of adjacent magnetoelectric composite units are exposed, and the flexible circuit board is pasted on the electrode layers on both sides of the magnetoelectric composite units by conductive glue, wherein the conductive glue covers the connection area between the electrode layer and the flexible circuit board, and then laser cutting is used to remove the temporary fixing areas to obtain an independent micro magnetoelectric composite device.
[0012] The present invention has the following beneficial effects: by introducing a CMP process to thin the PMNT material, both material thinning and surface flatness are achieved under high-frequency conditions; by combining a spin coating process with ion beam direct writing etching, the coupling consistency, geometric consistency, and relative position consistency of each device unit are ensured compared to manual pasting and manual assembly; and by combining advanced technologies such as CMP, electron beam evaporation, and ion beam direct writing etching, manual pasting is replaced, improving device fabrication efficiency. This ensures high precision and excellent consistency of the device structure. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 A schematic diagram of a process for preparing a micro-magnetic electric composite device provided by the present invention Figure 2 A structural diagram of a finished magnetoelectric composite device according to an embodiment of the present invention; Figure 3 The structure diagram of the magnetoelectric composite material in the embodiment of the present invention Description of Figure Numbers: 1. Magnetoelectric composite unit; 2. Flexible circuit board; 101. Piezoelectric material layer; 102. Electrode layer; 103. Magnetostrictive layer. DETAILED DESCRIPTION
[0014] The technical solution of the present invention is further elaborated in detail below in conjunction with the drawings and specific embodiments of the specification. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In the following description, reference is made to "some embodiments", which describes a subset of all possible embodiments, but it should be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.
[0015] In the following description, numerous specific details are provided to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without one or more of these details. In other instances, certain technical features well known in the art are not described to avoid confusion with the present invention.
[0016] It should be understood that the present invention can be implemented in different forms and should not be interpreted as being limited to the embodiments proposed herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. And the purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present invention. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates another way. It should also be understood that the terms "comprising" and / or "comprising" when used in this specification determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.
[0017] It should also be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "inner," "outer," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.
[0018] In order to fully understand the present invention, a detailed structure will be provided in the following description to illustrate the technical solution proposed by the present invention. Optional embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may also have other implementations.
[0019] Please refer to the attached Figures 1 to 3 The present application provides a method for preparing a micro-magnetoelectric composite device, the method comprising: thinning a piezoelectric material layer 101 to achieve a preset thickness and flatness requirement, depositing electrode layers 102 of the same thickness on both sides of the piezoelectric material layer 101 using a thin film deposition process, spin-coating a coupling layer on the electrode layers 102 on both sides, and adhering a magnetostrictive layer 103 on the coupling layer to form a magnetoelectric composite structure, ion-etching the formed magnetoelectric composite structure to form a plurality of magnetoelectric composite units 1, cutting the plurality of magnetoelectric composite units 1 and respectively adhering them to a flexible circuit board 2 to obtain a micro-magnetoelectric composite device.
[0020] In some optional embodiments, the piezoelectric material layer 101 is composed of manganese-doped lead magnesium niobate piezoelectric material. The manganese-doped lead magnesium niobate piezoelectric material has the highest electromechanical coupling coefficient currently available and can convert the obtained magnetic field energy to the greatest extent. The thinning treatment of the piezoelectric material layer 101 specifically includes: using a CMP process to remove uneven surface materials by combining chemical etching and mechanical grinding to achieve surface flatness.
[0021] Specifically, a 4-inch PMNT piezoelectric substrate is thinned to the required thickness, 0.2 mm in this embodiment, using a CMP (chemical mechanical polishing) process. The CMP machine used is a Huahai Qingke Universal-200. CMP combines chemical etching and mechanical polishing to remove surface irregularities and achieve atomic-level flatness. Polishing fluid is continuously dripped onto the polishing pad. The chemical components in the polishing fluid first react slightly with the material to be removed from the wafer surface, softening it. Then, the polishing head applies pressure and moves relative to the polishing pad to physically remove the reactants, achieving flatness.
[0022] Furthermore, in this embodiment, silicon dioxide with an average particle size of 100 nm and ceria with an average particle size of 10 nm were selected as the grinding solids to achieve a surface roughness of 10 nm-15 nm.
[0023] In some optional embodiments, the thin film deposition process is an electron beam evaporation process, the material of the electrode layer 102 is gold, and the thickness of the electrode layer 102 is 2 μm.
[0024] Specifically, the electrode is grown using an electron beam evaporation process. The material to be evaporated is bombarded by an electron beam from a charged tungsten filament. When the electron beam strikes the target material, its energy is converted into heat, causing it to evaporate and transform into a gas. In a high vacuum chamber, these evaporated atoms or molecules are then deposited on the substrate to form a thin film. In this embodiment, the electrode material is gold, and the evaporation system used is a Weikai E550 electron beam evaporation system. Considering the lower Curie temperature of PMNT, a planetary stage with a superimposed water cooling device is used. The electrode thickness is 2μm. In this embodiment, an electrode layer 102 of equal thickness is deposited on both sides of the piezoelectric substrate.
[0025] Furthermore, the evaporation rate set in the electron beam evaporation process is 0.1nm / s and the evaporation thickness is 2μm-2.5μm. In some optional embodiments, the coupling layer material is epoxy resin, and the thickness of the coupling layer is 0.5 μm.
[0026] Specifically, a coupling layer is spin-coated on the electrode layer 102 on one side by a SM-200 semi-automatic coating machine. The coupling layer material is epoxy resin and the thickness of the coupling layer is 0.5 μm. In some optional implementations, the magnetostrictive layer 103 is an amorphous alloy film, and the bonding process is achieved by electrostatic adsorption under dust-free conditions.
[0027] In some optional embodiments, the formed magnetoelectric composite structure is ion-etched to form a plurality of magnetoelectric composite units 1, specifically comprising: selectively removing material in a target area by controlling the energy beam scanning trajectory of the ion beam until penetrating the magnetostrictive layer 103, the coupling layer, the electrode layer 102 and a portion of the piezoelectric material layer 101, so as to obtain a plurality of independent magnetoelectric composite units 1 arranged at intervals and a temporary fixing area connected to the periphery thereof.
[0028] Specifically, the Ion500E ion beam etching system was used for etching. The ion beam energy was first set to 500-2000eV. This energy range can effectively bombard the material while avoiding excessive damage to the underlying material. At the same time, the beam current density was optimized to 10-50μA / cm according to the characteristics of the equipment. 2 The scanning trajectory of the ion beam is controlled by computer programming. Based on the pre-designed layout of multiple magnetoelectric composite units 1, the path of the target area where the material needs to be removed is accurately planned, and the ion beam is scanned along this trajectory.
[0029] During etching, the ion beam first bombards the magnetostrictive layer 103 on the top of the magnetoelectric composite structure, using the physical sputtering effect of ions to gradually remove the material of this layer; then, the ion beam continues to act on the coupling layer below, peeling it off layer by layer; then, the ion beam bombards the electrode layer 102 until the material of the electrode layer 102 is completely removed; finally, the ion beam etches the piezoelectric material layer 101, continuing to remove material until it penetrates part of the piezoelectric material layer 101, thereby completely removing the material in the target area. Throughout the etching process, the etching depth and time are strictly monitored, and the etching duration is accurately calculated based on the thickness of each layer and the etching rate, ensuring that the etching depth completely removes the material in the target area without damaging the adjacent magnetoelectric composite units 1 or the underlying support structure. At the same time, by adjusting the ion beam incident angle to maintain vertical incidence within ±5°, a sidewall perpendicularity close to 90° is achieved, reducing electromagnetic interference between adjacent units. Etching parameters are optimized to control the edge roughness of the magnetoelectric composite unit 1 to below 10nm, reducing the risk of stress concentration caused by edge unevenness. Ultimately, multiple independent magnetoelectric composite units 1 are arranged at intervals, and a temporary fixing area connecting them with a width of no more than 0.5mm is formed.
[0030] Furthermore, the ion beam direct writing etching technology uses an argon ion beam with an ion energy of 100 eV.
[0031] In some optional embodiments, multiple magnetoelectric composite units 1 are cut and then respectively pasted on a flexible circuit board 2, specifically comprising: cutting the multiple independent magnetoelectric composite units 1 and the temporary fixing areas connected to their peripheries along a preset cutting path, wherein the preset cutting path is located between adjacent magnetoelectric composite units 1 and avoids the temporary fixing areas, so that the opposite sides of adjacent magnetoelectric composite units 1 are exposed; the flexible circuit board 2 is pasted on the electrode layers 102 on both sides of the magnetoelectric composite unit 1 by conductive glue, wherein the conductive glue covers the connection area between the electrode layer 102 and the flexible circuit board 2; and then the temporary fixing areas are removed by laser cutting to obtain an independent micro magnetoelectric composite device, wherein the micro magnetoelectric composite device retains the piezoelectric body in the multiple push-pull structure formed after etching, wherein the multiple push-pull structure includes alternating magnetoelectric composite units 1 and spacing areas, wherein adjacent magnetoelectric composite units 1 generate stress in opposite directions under the action of an external magnetic field, and the piezoelectric effect of the piezoelectric body is superimposed to enhance the output of the electrical signal.
[0032] Specifically, in a dust-free environment, a high-precision cutting knife is used to operate on multiple magnetoelectric composite units 1 with temporary fixing areas. According to a pre-designed cutting plan, cutting is performed along a preset cutting path located between adjacent magnetoelectric composite units 1 and avoiding the temporary fixing areas. During the cutting process, the speed and force of the cutting knife are strictly controlled to ensure cutting accuracy, so that the relative sides of adjacent magnetoelectric composite units 1 are completely exposed without damaging the structure and performance of the magnetoelectric composite units 1.
[0033] After the cutting is completed, the conductive glue is evenly applied to the electrode layer 102 on both sides of the magnetoelectric composite unit 1 and the corresponding connection area of the flexible circuit board 2 to ensure that the conductive glue can completely cover the connection part between the electrode layer 102 and the flexible circuit board 2 to achieve a good electrical connection. The flexible circuit board 2 coated with the conductive glue is accurately aligned and pasted on the electrode layer 102 on both sides of the magnetoelectric composite unit 1. After the conductive glue is fully cured, the temporary fixing area is processed by laser cutting equipment, and the width of the temporary fixing area is set to no more than 0.5 mm. A laser beam with a spot diameter smaller than the width is selected, and the energy and cutting path of the laser are precisely controlled. The cutting is performed along the boundary of the temporary fixing area to completely remove the temporary fixing area, and finally an independent micro magnetoelectric composite device is obtained. After the cutting is completed, the device is inspected for appearance and performance tested to ensure that the device meets the design requirements.
[0034] Furthermore, the laser cutting process uses a nanosecond pulse fiber laser with a laser power of 5W and a cutting depth of no more than 0.5mm.
[0035] The device finally formed has an area of 3 mm×7 mm and contains a total of 6 magnetoelectric composite units 1. Each unit has a width of 0.5 mm and a length of 3 mm, and the interval between two units is 0.5 mm.
[0036] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. The scope of protection of the present invention should be based on the scope of protection of the claims.
Claims
1. A method for preparing a micro magnetoelectric composite device, characterized in that: The method includes: thinning a piezoelectric material layer to achieve a preset thickness and flatness requirement, depositing electrode layers of the same thickness on both sides of the piezoelectric material layer using a thin film deposition process, spin-coating a coupling layer on the electrode layers on both sides, and adhering a magnetostrictive layer on the coupling layer to form a magnetoelectric composite structure, ion-etching the formed magnetoelectric composite structure to form a plurality of magnetoelectric composite units, cutting the plurality of magnetoelectric composite units and pasting them onto a flexible circuit board to obtain a micro magnetoelectric composite device.
2. The method for preparing a micro magnetoelectric composite device according to claim 1, characterized in that: The thinning process for the piezoelectric material layer specifically includes: using a CMP process to remove surface uneven materials by combining chemical etching and mechanical grinding to achieve surface flatness.
3. The method for preparing a micro magnetoelectric composite device according to claim 1, characterized in that: Abrasive solids used in chemical mechanical polishing processes include silicon dioxide and ceria.
4. The method for preparing a micro magnetoelectric composite device according to claim 1, wherein: The thin film deposition process is an electron beam evaporation process, the material of the electrode layer is gold, and the thickness of the electrode layer is 2 μm.
5. The method for preparing a micro magnetoelectric composite device according to claim 1, characterized in that: The coupling layer material is epoxy resin, and the thickness of the coupling layer is 0.5 μm.
6. The method for preparing a micro magnetoelectric composite device according to claim 1, characterized in that: The magnetostrictive layer is an amorphous alloy film, and the bonding process is achieved by electrostatic adsorption under dust-free conditions.
7. The method for preparing a micro magnetoelectric composite device according to claim 1, characterized in that: The formed magnetoelectric composite structure is subjected to ion etching to form a plurality of magnetoelectric composite units, specifically comprising: selectively removing material in a target area by controlling the energy beam scanning trajectory of the ion beam until the material penetrates the magnetostrictive layer, the coupling layer, the electrode layer and part of the piezoelectric material layer, thereby obtaining a plurality of independent magnetoelectric composite units arranged at intervals and a temporary fixing area connected to the periphery thereof.
8. The method for preparing a micro magnetoelectric composite device according to claim 7, characterized in that: After cutting a plurality of magnetoelectric composite units, the units are respectively pasted on a flexible circuit board, specifically comprising: cutting the formed plurality of independent magnetoelectric composite units and the temporary fixing areas connected to their peripheries along a preset cutting path, wherein the preset cutting path is located between adjacent magnetoelectric composite units and avoids the temporary fixing areas, so that the opposite sides of adjacent magnetoelectric composite units are exposed; pasting the flexible circuit board on the electrode layers on both sides of the magnetoelectric composite units by means of conductive glue, wherein the conductive glue covers the connection area between the electrode layers and the flexible circuit board; and subsequently removing the temporary fixing areas by laser cutting to obtain an independent micro magnetoelectric composite device.