A method for preparing a piezoelectric resonator and interconnecting electrodes
By combining lithography technology and ultra-short pulse laser processing technology, the problem of difficulty in preparing high-precision piezoelectric resonators and interconnected electrodes is solved, and a fast and efficient preparation process is achieved, which significantly improves efficiency.
Patent Information
- Application Number
- CN202411840001.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-13
- Publication Date
- 2025-04-04
AI Technical Summary
It is difficult to quickly and efficiently prepare high-precision piezoelectric resonators and interconnected electrodes, especially the interconnected design of side electrodes is difficult to achieve.
Combining traditional lithography technology and ultra-short pulse laser precision machining technology, high-precision piezoelectric resonators and interconnected electrodes are gradually formed through deposition of metal films, photolithography processes, ultra-short pulse laser processing, peeling and corrosion methods.
It realizes the rapid and efficient preparation of high-precision piezoelectric resonators and interconnected electrodes, significantly improving efficiency and simplifying the process flow.
Smart Images
Figure CN119766178A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of sensor manufacturing, and in particular to a method for preparing a piezoelectric resonator and interconnecting electrodes. Background Art
[0002] Piezoelectric resonators, such as quartz piezoelectric resonators, are widely used in clock signal generation, gas sensitivity, acceleration and angular velocity sensitivity and other occasions. The normal operation of the device requires a carefully designed electrode structure, which not only includes the distribution of electrodes within the surface, but also the arrangement of corresponding electrodes on the side of the structure to achieve specific functions and extract stronger electrical signals. The preparation of the front electrode can be relatively easy to achieve through photolithography technology, but the interconnection design of the side electrode and the front electrode is difficult to achieve through conventional photolithography methods. In addition, the materials of piezoelectric resonators are usually quartz and piezoelectric ceramics, etc. The processing methods of these materials are usually mechanical cutting or corrosive liquid etching, which has low precision, complex process and long time consumption. The present invention proposes a preparation method by combining traditional photolithography technology and ultra-short pulse laser precision processing technology, which can quickly prepare high-precision piezoelectric resonators and corresponding front and side electrodes, significantly improving efficiency. Summary of the invention
[0003] 1. Technical issues to be resolved
[0004] In view of the above problems, the present invention provides a method for preparing a piezoelectric resonator and interconnecting electrodes, which is used to at least partially solve the technical problems such as the difficulty in preparing a piezoelectric resonator structure and interconnecting electrodes with side electrodes by traditional processing methods and the complexity of the process scheme.
[0005] (II) Technical solution
[0006] The present invention provides a method for preparing a piezoelectric resonator and interconnecting electrodes, comprising: S1, depositing a metal film I (2) on both sides of a piezoelectric material substrate wafer (1); S2, performing a photolithography process on the double-sided metal film I (2) to prepare a photoresist pattern (3) for subsequent regional segmentation of a surface metal film II (4); S3, processing the substrate wafer using an ultrashort pulse laser (5) to form a piezoelectric resonator piezoelectric resonator structure (6) and a side electrode segmentation structure (7) connected thereto; S4, using the photoresist pattern (3) as a mask to pattern the metal film I (2) and retain only the area covered by the photoresist pattern (3) ; S5, growing a metal film II (4) to cover the surface and sides of the piezoelectric resonant structure and the side electrode segmentation structure (7) as the material for the resonator interconnection electrode; S6, using a stripping method to remove the photoresist pattern (3) and the metal film II (4) attached thereto, and completing the regional segmentation of the upper and lower surface electrodes; S7, using a corrosion method to remove the metal film I (2) under the photoresist pattern (3); S8, using an ultrashort pulse laser (5) to cut the area where the photoresist pattern (3) in S2 is arranged on the side electrode segmentation structure (7), exposing the non-conductive section and removing the side electrode segmentation structure (7), and completing the regional segmentation of the side electrode.
[0007] Furthermore, the piezoelectric material is processed in the form of a wafer, including quartz, PZT, etc.
[0008] Furthermore, the side electrode segmentation structure (7) is an extension of the resonant structure (6) at a location where the surface electrode and the side electrode need to be interconnected in different regions.
[0009] Furthermore, the upper and lower surfaces of the side electrode segmentation structure (7) and the upper and lower surfaces of the resonator structure (6) are both coated with photoresist and are connected on the same surface.
[0010] Furthermore, the metal film I (2) and the metal film II (4) are made of different materials and can be selectively removed. The metal film I can be an aluminum film and the metal film II can be a Cr / Au composite film.
[0011] Furthermore, the growth method and conditions of the thin film in S5 can better cover the surface area and side area of the processing object, and the magnetron sputtering process is preferably used.
[0012] Furthermore, the thickness of the metal film I (2) and the metal film II (4) is between 50nm and 5um.
[0013] Furthermore, the ultrashort pulse laser (5) in S3 is a picosecond or femtosecond laser, and its energy density and duration are sufficient to completely cut through the piezoelectric material wafer substrate (1) or remove part of its thickness.
[0014] (III) Beneficial effects
[0015] The present invention proposes a preparation method by combining traditional photolithography technology and ultrashort pulse laser precision processing technology, which solves the technical problems of difficulty in preparing piezoelectric resonator structure and side interconnection electrodes by traditional processing methods and complex process schemes. High-precision piezoelectric resonators and corresponding surface and side interconnection electrodes can be quickly prepared, which significantly improves efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 A method for preparing a piezoelectric resonator and interconnecting electrodes according to an embodiment of the present invention is schematically shown.
[0017] Figure 2 This is a schematic diagram (cross-sectional view) of claims S1 and S2, in which a thin film is deposited and photolithography is performed.
[0018] Figure 3 It is a schematic diagram (cross-sectional view) of claims S3 and S4, in which a substrate wafer is processed by ultrashort pulse laser to form a resonant structure.
[0019] Figure 4 It is a schematic diagram of the structure after claim S4 (plan view). The structure has been processed by laser and is covered with photoresist at the position where division is required.
[0020] Figure 5 It is a schematic diagram (cross-sectional view) of claim S5, in which a metal film II (4) is grown to cover the surface and sides of the piezoelectric resonant structure and the side electrode segmentation structure (7) as the material for the resonator interconnecting electrodes.
[0021] Figure 6 It is a schematic diagram (cross-sectional view) of claims S6 and S7, wherein a stripping method is used to remove a photoresist pattern (3) and a metal film II (4) attached thereto, and an etching method is used to remove a metal film I (2) under the photoresist pattern (3).
[0022] Figure 7 This is a plan view after claim S8 is completed, and the resonator processing is completed. DETAILED DESCRIPTION
[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.
[0024] An embodiment of the present invention provides a method for preparing a piezoelectric resonator and interconnecting electrodes, see Figure 1 , Figure 2, comprising: S1, depositing a metal film I (2) on both sides of a piezoelectric material substrate wafer (1); S2, performing a photolithography process on the double-sided metal film I (2) to prepare a photoresist pattern (3), wherein the photoresist pattern (3) includes regions arranged on the upper and lower surfaces of the resonator structure (6) and regions arranged on the upper and lower surfaces of the side electrode segmentation structure (7), which are used for subsequent regional segmentation of the surface metal film II (4); S3, processing the substrate wafer using an ultrashort pulse laser (5) to form a piezoelectric resonator structure (6) and a side electrode segmentation structure (7) connected thereto; S4, using the photoresist pattern (3) as a mask to pattern the metal film I (2), retaining only the region to be segmented. The method comprises the following steps: step S1, growing a metal film II (4) to cover the surface and sides of the piezoelectric resonant structure and the side electrode segmentation structure (7) and serving as the material for the resonator interconnection electrode; step S2, removing the photoresist pattern (3) and the metal film II (4) attached thereto by a stripping method, and completing the regional segmentation of the electrodes on the upper and lower surfaces; step S3, removing the metal film I (2) below the photoresist pattern (3) by an etching method; and step S4, cutting the region where the photoresist pattern (3) in step S2 is arranged on the side electrode segmentation structure (7) by an ultrashort pulse laser (5), exposing the non-conductive section and removing the side electrode segmentation structure (7), and completing the regional segmentation of the side electrode.
[0025] In the above implementation process, a layer of metal film is first deposited on both sides, and its main functions are as follows: 1. Shielding the light passing through the substrate during double-sided lithography. The preparation of the structure usually requires double-sided lithography, generally one side is done first and then the other side. If one side has been exposed, when doing the other side, if the material substrate is transparent, such as quartz, the exposed side will be affected by the transmitted light, which is easy to cause lithography failure. The addition of this metal layer can shield the light passing through the substrate to avoid damage caused by it. 2. Shielding scattered laser during laser processing. When there is photoresist near the laser processing area, the light scattered from the processing area when the substrate is transparent will damage the photoresist pattern, or even cause it to fall off, lose the masking effect, and cause unsatisfactory processing results. Although the metal film layer is thin, it can block the scattered laser and protect the photoresist pattern; 3. As a sacrificial layer to remove dust generated during laser processing. Ultrashort pulse lasers can process various materials with high precision, but they will generate dust and deposit on the surface of the processed sample, which is not easy to remove. After adding this layer of metal film, the dust generated by laser processing is deposited on the surface of this metal film layer, and the dust can be easily peeled off when the metal film layer is removed by corrosion later. 4. The formation of a collapsed structure is easy to peel off as an electrode metal II film layer. The stripping process removes the film layer attached to the photoresist by dissolving the photoresist with an organic solvent. If the film layer covers the photoresist very tightly, it is not easy for the organic solvent to penetrate into the photoresist and cannot dissolve it quickly. By introducing a metal film I, a photoresist pattern is formed on it and then the film layer is corroded and removed. In this process, a part of the metal film at the edge of the photoresist will also be corroded, forming a metal film I of a certain thickness with a photoresist with a slightly larger coverage range, that is, a collapsed structure. When growing a metal film II, it is easier to form discontinuous coverage at the collapsed part, and it is easier for the organic solvent to penetrate during stripping.
[0026] In the above implementation process, the electrode on the resonator structure is a metal film II (4). The electrode structure is divided into different areas, and the formation of different areas is achieved by segmenting the metal film II, and the areas are insulated. Electrodes can be arranged on the upper and lower surfaces and each side of the resonator structure, and the two can be interconnected to enhance the signal. The regional segmentation of the upper and lower surfaces is achieved by peeling off the metal film II (4) with a photoresist pattern (3), and the regional segmentation of the side electrode is achieved by laser cutting the side electrode segmentation structure (7). When the front electrode and the side electrode are interconnected according to the area, it is achieved by arranging the photoresist pattern (3) on the side electrode segmentation structure (7). The side electrode segmentation structure (7) is a part of the resonator structure (6) extending outward. After S5 is implemented, a metal film II is attached to its side. The structure is removed by laser cutting, and the metal film II on the side is also removed together, that is, the segmentation of the side electrode of the resonator structure (6) is completed. However, after the side segmentation, the electrodes in different areas may still be conductive. The reason is that after S5 is implemented, the metal film II covers the upper and lower surfaces and sides of the resonator structure (6) and the side electrode segmentation structure (7), and it is possible to conduct through the upper and lower surfaces. Therefore, the photoresist structure (3) is arranged as a connected area on the upper and lower surfaces of the resonator structure (6) and the side electrode segmentation structure (7). After S8 is implemented, the segmentation area on the side produced by laser processing and the segmentation area on the upper and lower surfaces formed by photoresist are connected together, and the electrodes on the surface and the side are segmented.
[0027] In the above implementation process, the metal film I (2) and the metal film II (4) are made of different materials and can be selectively removed. The metal film I can be an aluminum film and the metal film II can be a Cr / Au composite film. When the above materials are selected, the thickness of the aluminum film is 300nm and the thickness of the Cr / Au composite film is 50nm / 250nm.
[0028] The present invention is described below with a specific embodiment. The processing sequence is as follows: Figure 1 The following are the detailed descriptions of each step:
[0029] S1, a 300 nm thick Al film (2) is grown on both sides of a quartz substrate (1) by magnetron sputtering.
[0030] S2, photolithography is performed on the double-sided aluminum film (2) to prepare a photolithography pattern (3), the photoresist selected is AZ6130, and the thickness is about 2.5um. The photolithography pattern (3) is arranged into a connected area on the upper and lower surfaces of the resonant structure (6) and the side electrode segmentation structure (7).
[0031] S3, using a picosecond laser (5) to process and cut the wafer after step S2 to form a resonant structure (6) and a part of the extended side electrode segmentation structure (7).
[0032] S4, using the photolithography pattern (3) as a mask, etching the Al film (2) with an aluminum etching solution to complete the patterning of the aluminum film.
[0033] S5, magnetron sputtering is used to grow a CrAu film (4) on both sides, wherein Cr is 50nm and Au is 250nm; magnetron sputtering has good step coverage capability, and the sides of the resonant structure (6) and the side electrode segmentation structure (7) are also coated with a CrAu film.
[0034] S6, removing the photoresist pattern (3) and the CrAu film (4) attached thereto by a stripping method.
[0035] S7, using aluminum etching solution to remove the Al film (2) below the photoresist pattern (3) exposed after S6.
[0036] S8, using picosecond laser to cut off the side electrode segmentation structure (7), completing the device preparation and electrode segmentation and interconnection.
[0037] The specific embodiments 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 embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing a piezoelectric resonator and interconnecting electrodes, comprising: S1, depositing a metal thin film I (2) on both sides of a piezoelectric material substrate wafer (1); S2, performing a photolithography process on the double-sided metal film I (2) to prepare a photoresist pattern (3) for subsequent regional segmentation of the surface metal film II (4); S3, using an ultrashort pulse laser (5) to process the substrate wafer to form a piezoelectric resonant structure (6) of the piezoelectric resonator and a side electrode segmentation structure (7) connected thereto; S4, using the photoresist pattern (3) as a mask, patterning the metal film I (2); S5, growing a metal film II (4) to cover the surface and side surfaces of the piezoelectric resonant structure and the side electrode segmentation structure (7) as a material for the resonator interconnection electrode; S6, removing the photoresist pattern (3) and the metal film II (4) attached thereto by a stripping method, and completing the area segmentation of the upper and lower surface electrodes; S7, removing the metal film I (2) below the photoresist pattern (3) by an etching method; S8, using an ultrashort pulse laser (5) to cut the area where the photoresist pattern (3) in S2 is arranged on the side electrode segmentation structure (7), exposing the non-conductive section and removing the side electrode segmentation structure (7), thereby completing the area segmentation of the side electrode.
2. A method for preparing a piezoelectric resonator and interconnecting electrodes according to claim 1, characterized in that The piezoelectric materials are processed in wafer form and include quartz, PZT, etc.
3. A method for preparing a piezoelectric resonator and interconnecting electrodes according to claim 1, characterized in that The side electrode segmentation structure (7) is an extension of the resonant structure (6) at a location where the surface electrode and the side electrode need to be interconnected in different regions.
4. A method for preparing a piezoelectric resonator and interconnecting electrodes according to claim 1, characterized in that: The upper and lower surfaces of the side electrode segmentation structure (7) and the upper and lower surfaces of the resonator structure (6) are both coated with photoresist and are connected on the same surface.
5. A method for preparing a piezoelectric resonator and interconnecting electrodes according to claim 1, characterized in that The metal film I (2) and the metal film II (4) are made of different materials and can be selectively removed, for example, the metal film I is an aluminum film and the metal film II is a Cr / Au composite film.
6. A method for preparing a piezoelectric resonator and interconnecting electrodes according to claim 1, characterized in that The growth method and conditions of the thin film in S5 can better cover the surface area and side area of the processing object, and the magnetron sputtering process is preferred.
7. A method for preparing a piezoelectric resonator and interconnecting electrodes according to claim 1, characterized in that The thickness of the metal film I (2) and the metal film II (4) is between 50nm and 5um.
8. A method for preparing a piezoelectric resonator and interconnecting electrodes according to claim 1, characterized in that The ultrashort pulse laser (5) in S3 is a picosecond or femtosecond laser, and its energy density and duration can completely cut through the piezoelectric material wafer substrate (1) or remove part of its thickness.