Scanning mirror and method of making the same, radar, electronic device

Abstract

This application provides a scanning mirror and its fabrication method, as well as radar and electronic devices, relating to the field of electronic devices. It aims to address the problems of current scanning mirrors requiring the deposition of an insulating layer, resulting in complex processes and insufficient surface stress on the mirror surface after insulating layer deposition. The scanning mirror includes a first region, and second and third regions located outside the first region. It also includes a substrate, and a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on the substrate. The first electrode, piezoelectric layer, and second electrode form a mirror structure in the first region; the first electrode, piezoelectric layer, and second electrode form a piezoelectric actuator in the second region; the first electrode includes a first pad located in the third region, the second electrode includes a second pad located in the third region, and the piezoelectric layer includes an insulating portion located between the first and second pads. The scanning mirror of this application not only eliminates the need for insulating layer deposition, saving on the process, but also exhibits good surface stress on the mirror surface.

Description

Technical Field

[0001] This application relates to the field of semiconductor processes, and more particularly to a scanning mirror and its fabrication method, radar, and electronic equipment. Background Technology

[0002] Currently, the design of MEMS scanning mirrors based on PZT (Lead Zirconate Titanate) piezoelectric thin films typically requires six photolithography and etching processes. During the design process, electrical interconnection between the drive arm and the electrodes is necessary, requiring metal traces between them. Current methods often involve depositing silicon oxide and aluminum oxide insulating layers on the wafer surface, followed by photolithography and etching to remove part of the insulating layer, then photolithographic patterning, gold plating, and metal lift-off to achieve the electrical interconnection between the drive arm and the electrodes. This method requires insulating layer deposition, photolithographic patterning, and insulating layer etching, making the process complex and expensive. Furthermore, the surface stress of the mirror structure after insulating layer deposition is insufficient. Summary of the Invention

[0003] This application proposes a scanning mirror and its fabrication method, as well as radar and electronic equipment, aiming to improve the problem of complex processes that require insulating layer deposition, photolithography patterning, and insulating layer etching.

[0004] To achieve the above objectives, this application provides a scanning mirror comprising a first region, and a second region and a third region sequentially located outside the first region; the scanning mirror further comprises a substrate, and a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on the substrate, wherein the first electrode, the piezoelectric layer, and the second electrode form a mirror structure in the first region; the first electrode, the piezoelectric layer, and the second electrode form a piezoelectric actuator in the second region; the first electrode further comprises a first pad located in the third region, and the second electrode further comprises a second pad located in the third region, wherein the orthographic projection of the first pad on the substrate and the orthographic projection of the second pad on the substrate at least partially overlap, and the piezoelectric layer further comprises an insulating portion located between the first pad and the second pad.

[0005] In the scanning mirror described above, the piezoelectric layer not only insulates the first electrode and the second electrode in the first region and the mirror structure in the second region, but also forms an insulating layer between the first pad and the second pad in the third region, thus improving the lifespan of the scanning mirror. Furthermore, the elimination of the need for additional alumina and silicon oxide deposition as an insulating layer between the first and second pads reduces the impact of thermal stress during processing, lowers surface stress, reduces mirror deformation, and also reduces time and cost.

[0006] In some embodiments, the outer boundary of the orthographic projection of the piezoelectric layer on the substrate coincides with the outer boundary of the orthographic projection of the first electrode on the substrate.

[0007] In some embodiments, in the third region, the piezoelectric layer includes a through-hole that exposes the first electrode.

[0008] In some embodiments, the substrate includes a cavity, and the orthographic projection of the mirror structure onto the substrate lies within the cavity.

[0009] In some embodiments, the scanning mirror further includes a dielectric layer located between the substrate and the first electrode. The substrate includes a first silicon layer, silicon dioxide, and a second silicon layer stacked sequentially. The dielectric layer is located between the first electrode and the second silicon layer. The second silicon layer includes a cantilever beam for connecting the first region and the second region.

[0010] In some embodiments, the fabrication method includes: sequentially forming a first electrode and a piezoelectric layer on a substrate, the substrate including a first region and a second region and a third region sequentially located outside the first region; etching the piezoelectric layer to disconnect the piezoelectric layer between the first region and the second region, the piezoelectric layer further including an insulating portion located in the third region, the insulating portion having a via formed therein; etching the first electrode to disconnect the first electrode between the first region and the second region, the first electrode including a first pad located in the third region; forming a second electrode on the side of the piezoelectric layer away from the substrate, the orthographic projection of the second electrode on the substrate being offset from the via, the second electrode including a second pad located in the third region; the orthographic projections of the second pad and the first pad on the substrate at least partially overlapping, the insulating portion being located between the second pad and the first pad.

[0011] The fabrication method in the above embodiments involves first forming a first electrode and a piezoelectric layer on a substrate, then disconnecting the piezoelectric layer and the first electrode in a first region and a second region, respectively. The first electrode forms a first pad in a third region, while the piezoelectric layer forms an insulating portion in the third region. For the subsequent conductivity of the second electrode, vias are formed in the insulating portion. Then, a second electrode is formed, which, together with the first electrode and the piezoelectric layer in the first region, forms a mirror mechanism. The second electrode, together with the first electrode and the piezoelectric layer in the second region, forms a piezoelectric actuator. The second electrode serves as a second pad in the third region, and is offset from the vias in the insulating portion. Thus, the piezoelectric layer not only serves as the piezoelectric film in the piezoelectric actuator in the second region but also acts as an insulating portion in the third region, isolating the first and second pads. This eliminates the need for additional alumina and silicon oxide deposition as an insulating layer between the first and second pads, reducing the impact of thermal stress during processing, reducing surface stress and deformation of the mirror, and also reducing time and cost.

[0012] In some embodiments, the substrate includes a first silicon layer, silicon dioxide, and a second silicon layer stacked sequentially; before forming a first electrode on the substrate, a dielectric layer is formed on the side of the second silicon layer away from the silicon dioxide; after forming a second electrode, the dielectric layer and the second silicon layer are etched to form a cantilever beam.

[0013] In some embodiments, after etching the second silicon layer, a substrate is disposed on the side of the second electrode away from the first electrode; then the first silicon layer is etched to form a cavity; the silicon dioxide is etched through the cavity to remove the substrate.

[0014] The scanning mirror fabrication method in the above embodiments not only insulates the first electrode and the second electrode in the first region and the second region respectively from the mirror structure in the first region and the piezoelectric actuator in the second region, but also forms an insulating layer between the first pad and the second pad in the third region, thus improving the service life of the scanning mirror. Furthermore, it eliminates the need for additional alumina and silicon oxide deposition as an insulating layer between the first and second pads, reducing the impact of thermal stress during processing, reducing mirror surface stress, reducing mirror deformation, and also reducing time and cost.

[0015] In another aspect of this application, a radar is provided that includes the scanning mirror in any of the above embodiments.

[0016] The radar in the above embodiments has the same technical effect as the scanning mirror in the above embodiments.

[0017] In another aspect of this application, an electronic device is provided, which includes the scanning mirror in any of the above embodiments.

[0018] The electronic device in the above embodiments has the same technical effect as the scanning mirror in the above embodiments. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in some embodiments of this application will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not actual dimensions of the products or actual processes of the methods involved in the embodiments of this application.

[0020] Figure 1 A process structure diagram of a scanning mirror provided in an embodiment of this application; Figure 2 A schematic diagram illustrating a method for preparing a scanning mirror according to an embodiment of this application; Figure 3 This is a schematic diagram illustrating another method for preparing a scanning mirror provided in an embodiment of this application. Detailed Implementation

[0021] The technical solutions in some embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application are within the scope of protection of this application.

[0022] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open and encompassing, that is, "including, but not limited to".

[0023] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0024] In describing some embodiments, the term "connection" and its derivative expressions may be used. The term "connection" should be interpreted broadly; for example, "connection" can be a fixed connection, a detachable connection, or an integral part. It can be a direct connection or an indirect connection through an intermediate medium. For example, in describing some embodiments, the term "connection" may be used to indicate that two or more components have direct physical or electrical contact with each other.

[0025] In addition, the use of "based on" implies openness and inclusivity, because processes, steps, calculations or other actions "based on" one or more conditions or values ​​can in practice be based on additional conditions or values ​​beyond those conditions.

[0026] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0027] like Figure 1 As shown, this application provides a scanning mirror 1, which includes a first region 11 and a second region 12 and a third region 13 located sequentially outside the first region 11; the scanning mirror also includes a substrate 20, and a first electrode 21, a piezoelectric layer 22 and a second electrode 23 sequentially stacked on the substrate 20, wherein the first electrode 21, the piezoelectric layer 22 and the second electrode 23 form a mirror structure 101 in the first region 10; the first electrode 21, the piezoelectric layer 22 and the second electrode 23 form a piezoelectric actuator in the second region 12; the first electrode 21 also includes a first pad 210 located in the third region 13, and the second electrode 23 also includes a second pad 230 located in the third region 13, wherein the orthographic projection of the first pad 210 on the substrate 20 and the orthographic projection of the second pad 230 on the substrate 20 at least partially overlap, and the piezoelectric layer 22 also includes an insulating portion 220 located between the first pad 210 and the second pad 230.

[0028] In some embodiments, such as Figure 1 As shown, the outer boundary of the orthographic projection of the piezoelectric layer 22 on the substrate 20 coincides with the outer boundary of the orthographic projection of the first electrode 21 on the substrate 20.

[0029] In some embodiments, such as Figure 1 As shown, in the third region 13, the piezoelectric layer 22 includes a through-hole 221 that exposes the first electrode 21.

[0030] In some embodiments, such as Figure 1As shown, the substrate 20 includes a cavity 2010, and the orthographic projection of the mirror structure 101 on the substrate 20 is located within the cavity 2010.

[0031] In some embodiments, such as Figure 1 As shown, the scanning mirror 1 further includes a dielectric layer 40, which is located between the substrate 20 and the first electrode 21. The substrate 20 includes a first silicon layer 201, a silicon dioxide layer 202, and a second silicon layer 203 stacked sequentially. The dielectric layer 40 is located between the first electrode 21 and the second silicon layer 203. The second silicon layer 203 includes a cantilever beam for connecting the first region 11 and the second region 12.

[0032] like Figure 1 and Figure 2 As shown, another aspect of this application provides a method for fabricating a scanning mirror. The method includes: sequentially forming a first electrode 21 and a piezoelectric layer 22 on a substrate 20, wherein the substrate 20 includes a first region 11, and a second region 12 and a third region 13 sequentially located outside the first region 11; etching the piezoelectric layer 22 to break it between the first region 11 and the second region 12, wherein the piezoelectric layer 22 further includes an insulating portion 220 located in the third region 13, and a through-hole 221 is formed in the insulating portion 220; etching the first electrode 21 to break it between the first region 11 and the second region 12. 1. A break is formed between the first region 11 and the second region 12. The first electrode 21 includes a first pad 210 located in the third region 13. A second electrode 23 is formed on the side of the piezoelectric layer 22 away from the substrate 20. The orthographic projection of the second electrode 23 on the substrate 20 is offset from the via 221. The second electrode 23 includes a second pad 230 located in the third region 13. The orthographic projections of the second pad 230 and the first pad 210 on the substrate 20 at least partially overlap. The insulating portion 220 is located between the second pad 230 and the first pad 210.

[0033] like Figure 2 and Figure 3 As shown, in some embodiments, the substrate 20 includes a first silicon layer 201, silicon dioxide 202 and a second silicon layer 203 stacked sequentially; before forming the first electrode 21 on the substrate 20, a dielectric layer 40 is formed on the side of the second silicon layer 203 away from the silicon dioxide 202; after forming the second electrode 23, the dielectric layer 40 and the second silicon layer 203 are etched to form a cantilever beam.

[0034] like Figure 3As shown, in some embodiments, after etching the second silicon layer 203, a substrate 50 is disposed on the side of the second electrode 23 away from the first electrode 21; then the first silicon layer 201 is etched to form a cavity 2010; the silicon dioxide 202 is etched through the cavity 2010 to remove the substrate 50.

[0035] In another aspect, this application provides a radar comprising the scanning mirror described in any of the above embodiments.

[0036] In another aspect of this application, an electronic device is provided, which includes the scanning mirror in any of the above embodiments.

[0037] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A scanning mirror, characterized in that, It includes a first region, and a second region and a third region located sequentially outside the first region; The scanning mirror further includes a substrate, and a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on the substrate. The first electrode, the piezoelectric layer, and the second electrode form a mirror structure in the first region; the first electrode, the piezoelectric layer, and the second electrode form a piezoelectric actuator in the second region. The first electrode further includes a first pad located in the third region, and the second electrode further includes a second pad located in the third region. The orthographic projection of the first pad on the substrate and the orthographic projection of the second pad on the substrate at least partially overlap. The piezoelectric layer further includes an insulating portion located between the first pad and the second pad.

2. The scanning mirror according to claim 1, characterized in that, The outer boundary of the piezoelectric layer's orthogonal projection on the substrate coincides with the outer boundary of the first electrode's orthogonal projection on the substrate.

3. The scanning mirror according to claim 1, characterized in that, In the third region, the piezoelectric layer includes a through-hole that exposes the first electrode.

4. The scanning mirror according to claim 1, characterized in that, The substrate includes a cavity, and the orthographic projection of the mirror structure onto the substrate lies within the cavity.

5. The scanning mirror according to claim 1, characterized in that, The scanning mirror further includes a dielectric layer located between the substrate and the first electrode. The substrate includes a first silicon layer, a silicon dioxide layer, and a second silicon layer stacked sequentially. The dielectric layer is located between the first electrode and the second silicon layer. The second silicon layer includes a cantilever beam for connecting the first region and the second region.

6. A method for preparing a scanning mirror, characterized in that, The preparation method includes: A first electrode and a piezoelectric layer are sequentially formed on a substrate, the substrate including a first region, and a second region and a third region located sequentially outside the first region; The piezoelectric layer is etched to break it between the first region and the second region. The piezoelectric layer also includes an insulating portion located in the third region, in which a via is formed. The first electrode is etched to disconnect it between the first region and the second region, the first electrode including a first pad located in the third region; A second electrode is formed on the side of the piezoelectric layer away from the substrate. The orthographic projection of the second electrode on the substrate is offset from the via. The second electrode includes a second pad located in the third region. The orthographic projections of the second pad and the first pad on the substrate at least partially overlap. The insulating portion is located between the second pad and the first pad.

7. The method for preparing a scanning mirror according to claim 6, characterized in that, The substrate comprises a first silicon layer, silicon dioxide, and a second silicon layer stacked sequentially. Before forming the first electrode on the substrate, a dielectric layer is formed on the side of the second silicon layer away from the silicon dioxide; After forming the second electrode, the dielectric layer and the second silicon layer are etched to form a cantilever beam.

8. The method for preparing a scanning mirror according to claim 7, characterized in that, After etching the second silicon layer, a substrate is disposed on the side of the second electrode away from the first electrode; Then the first silicon layer is etched to form a cavity; The silicon dioxide is etched through the cavity to remove the substrate.

9. A radar, characterized in that, The radar includes the scanning mirror as described in any one of claims 1-5.

10. An electronic device, characterized in that, The electronic device includes the scanning mirror as described in any one of claims 1-5.

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