Capacitive laser power mirror based on MEMS technology and preparation method thereof

Abstract

The invention discloses a capacitive laser power mirror based on an MEMS technology. The capacitive laser power mirror comprises an integrated chip structure; the chip structure comprises an annular outer frame, a central oscillator, Archimedes spiral beams, outer frame fan-shaped anchor points and oscillator fan-shaped anchor points. The central oscillator is positioned in the geometric center of the annular outer frame; the outer frame fan-shaped anchor points are integrally formed on the inner edge of the annular outer frame; the oscillator fan-shaped anchor points are integrally formed on the outer edge of the central oscillator; the Archimedes spiral beams are connected between the annular outer frame and the central oscillator, the first ends of the Archimedes spiral beams are connected to the outer frame fan-shaped anchor points, and the second ends of the Archimedes spiral beams are connected to the oscillator fan-shaped anchor points. The fan-shaped anchor points are respectively arranged on the inner edge of the annular outer frame of the chip structure and the outer edge of the central oscillator, so that the two ends of the Archimedes spiral beam are respectively connected with the annular outer frame and the central oscillator through the fan-shaped anchor points in smooth transition, and a slit generated in the prior art is avoided; the problem of measurement result distortion caused by stress concentration of the chip structure is solved.

Description

Technical Field

[0001] This invention belongs to the field of laser power detection, and in particular to a capacitive laser power mirror based on MEMS technology and its fabrication method. Background Technology

[0002] High-precision laser power measurement plays a crucial role in industrial processing, scientific research, and national defense. To meet the demand for direct measurement of high-power lasers, capacitive laser power mirrors with fast response and a large dynamic measurement range have become an important development direction in this field. The core of this type of device is a microelectromechanical system (MEMS) variable capacitor structure consisting of a movable oscillator, a support beam, and a fixed outer frame.

[0003] Existing capacitive laser power mirrors typically use an Archimedean spiral beam as the support structure. In microfabrication processes, such as... Figure 2 As shown, the connection between the supporting beam and the external frame and the central oscillator typically forms a steep vertical connection interface. This connection shape will create a deep concave corner structure in the dry etching process. Due to the process characteristics of anisotropic etching, the etchant is difficult to effectively remove the material in these dead corners, and inevitably leaves wedge-shaped etching residue slits with a large depth-to-width ratio at the connection between the beam and the structure.

[0004] These structural slits and their accompanying concave angles induce significant stress concentration effects. When the oscillator reciprocates under optical pressure, stress becomes highly concentrated in these slits and sharp corners, drastically reducing the device's fatigue life, easily inducing microcracks, and even causing structural fracture, severely compromising the mechanical reliability of the power mirror. More importantly, the stress concentration effect also introduces nonlinear mechanical response characteristics, causing the relationship between the oscillator displacement and the applied optical pressure to deviate from the ideal linear characteristics, resulting in distorted measurement results, calibration difficulties, and ultimately limiting the measurement accuracy and long-term stability of the laser power mirror. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of stress concentration and measurement distortion caused by the narrow gap in the connection between the vibrating beam and the fixed outer frame in the prior art, and to provide a capacitive laser power mirror based on MEMS technology and its preparation method.

[0006] To achieve the above objectives, the present invention employs the following technical solution: The present invention discloses a capacitive laser power mirror based on MEMS technology, comprising: an integrally formed chip structure (6). The chip structure (6) includes: an annular outer frame (1), a central oscillator (2), an outer frame fan-shaped anchor point (4), an oscillator fan-shaped anchor point (5), and an Archimedes spiral beam (3); The central oscillator (2) is located at the geometric center of the annular outer frame (1); The outer frame fan-shaped anchor point (4) is integrally formed on the inner edge of the annular outer frame (1), and the outer edge curvature of the outer frame fan-shaped anchor point (4) is the same as the inner edge curvature of the annular outer frame (1). The oscillator fan-shaped anchor point (5) is integrally formed on the outer edge of the central oscillator (2), and the inner edge curvature of the oscillator fan-shaped anchor point (5) is the same as the outer edge curvature of the central oscillator (2); The Archimedes spiral beam (3) is connected between the annular outer frame (1) and the central oscillator (2), and the first end of the Archimedes spiral beam (3) is connected to the fan-shaped anchor point (4) of the outer frame, and the second end is connected to the fan-shaped anchor point (5) of the oscillator.

[0007] The number of Archimedes spiral beams (3) is multiple; Multiple Archimedean spiral beams (3) are evenly distributed along the circumference of the annular outer frame (1); Correspondingly, the number of the outer frame sector anchor points (4) and the oscillator sector anchor points (5) are respectively corresponding to the number of the Archimedes spiral beams (3); Each Archimedes spiral beam (3) is connected between one of the outer frame sector anchor points (4) and one of the oscillator sector anchor points (5).

[0008] The MEMS-based capacitive laser power mirror also includes an insulating material ring (7). The number of chip structures (6) is two, and the functional surfaces of the two chip structures (6) are packaged face to face, and the functional surface is the side that can form a capacitor plate; The insulating material ring (7) is located between the annular outer frame (1) of the two chip structures (6).

[0009] The Archimedes spiral beam (3) has a rotation angle of 360 degrees.

[0010] The radius of the central oscillator (2) is 4~6mm.

[0011] The outer diameter of the annular outer frame (1) is 15~17mm and the inner diameter is 11~12mm.

[0012] The insulating material ring (7) is made of polyimide and has a thickness of 1900~2100μm.

[0013] This invention also discloses a method for fabricating the MEMS-based capacitive laser power mirror, comprising the following steps: S1. The first photolithography pattern is formed on the front side of the silicon wafer to form the area of ​​the central oscillator (2). A silver metal layer is prepared by magnetron sputtering and the reflective mirror of the central oscillator is formed by a lift-off process. S2. A second photolithography pattern is formed on the front side of the wafer after the silver metal layer is prepared, forming the region of Archimedes spiral beam (3), outer frame fan-shaped anchor point (4) and oscillator fan-shaped anchor point (5), and chromium metal layer and copper metal layer are sputtered sequentially in the spiral beam and fan-shaped anchor point regions, and a chromium / copper composite metal layer is formed by peeling process; S3. Perform a third photolithography pattern on the front side of the silicon wafer after all metal layers have been prepared to form a chip structure (6) pattern. Use the silver metal layer and chromium / copper composite metal layer as etching masks to perform dry etching on the silicon wafer to integrally form a chip structure (6) including an annular outer frame (1), an Archimedes spiral beam (3), an outer frame fan-shaped anchor point (4), an oscillator fan-shaped anchor point (5), and a central oscillator (2).

[0014] 9. The method for fabricating a capacitive laser power mirror based on MEMS technology according to claim 8, characterized in that, after S3, it further includes: S4. Prepare another chip structure (6) according to steps S1-S3. S5. Place the two prepared chip structures (6) with the chromium / copper composite metal layer facing each other, and set an insulating material ring (7) between the annular outer frame of the two chip structures (6). S6. Bond and encapsulate the two chips with an insulating material ring (7).

[0015] The thickness of the silicon wafer is 180~200μm.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention adopts an integrally formed chip structure and sets fan-shaped anchor points on the inner edge of the annular outer frame and the outer edge of the central oscillator respectively, so that the two ends of the Archimedes spiral beam are connected to the annular outer frame and the central oscillator respectively through the fan-shaped anchor points with smooth transition. This avoids the wedge-shaped etching residual slits with a large depth-to-width ratio generated during the dry etching process in the traditional vertical connection method, fundamentally eliminating the stress concentration phenomenon caused by the structural slits, and solving the technical problem of measurement result distortion and reliability reduction caused by stress concentration in the chip structure in the prior art. (2) This invention uses an Archimedes spiral beam with a rotation angle of 360° as the support structure and combines finite element simulation optimization design to make the overall stress distribution more uniform when the beam deforms under light pressure. While significantly reducing the stiffness of the beam structure to improve the sensitivity of light radiation pressure measurement, it greatly improves the fatigue characteristics of the structure and solves the technical problem of high sensitivity and high reliability being difficult to balance. (3) The present invention uses MEMS dry etching process to integrally form a spiral beam structure. It utilizes the anisotropic etching characteristics to obtain a high-precision microbeam morphology with good edge quality and high perpendicularity. Compared with the traditional wet etching process, it significantly improves the dimensional uniformity and mechanical property consistency of the beam structure and solves the technical problem that insufficient microbeam fabrication precision affects the stability of sensor performance. (4) By adopting a dual-chip symmetrical packaging structure, the present invention utilizes polyimide ring isolation to form a precise capacitor gap, so that the two central oscillators are in a symmetrical equilibrium state in the gravitational field, effectively offsetting the static displacement error caused by gravity, and solving the technical problem of the change in initial capacitor spacing caused by gravity drooping in the traditional single-sided movable capacitor structure, which affects the measurement accuracy. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the integrally formed chip structure in this invention; Figure 2 This is a schematic diagram of the slit at the connection between the vibrating beam and the central oscillator in the prior art; Figure 3 This is a side view of the integrally formed chip structure in this invention; Figure 4 This is a schematic diagram of a dual-chip structure package according to an embodiment of the present invention; Wherein: 1-ring outer frame; 2-central oscillator; 3-Archimedes spiral beam; 4-outer frame sector anchor point; 5-oscillator sector anchor point; 6-chip structure; 7-insulating material ring; 8-slit. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0024] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0025] The present invention will now be described in further detail with reference to the accompanying drawings: See Figure 1 The present invention discloses a capacitive laser power mirror based on MEMS technology, comprising: an integrally formed chip structure 6; The chip structure 6 includes: an annular outer frame 1, a central oscillator 2, an Archimedean spiral beam 3, an outer frame sector anchor point 4, and an oscillator sector anchor point 5; The outer diameter of the annular outer frame 1 is 15~17mm, and the inner diameter is 11~12mm; the radius of the central oscillator 2 is 4~6mm; In one embodiment, the annular outer frame 1 preferably has an outer diameter of 16 mm and an inner diameter of 11.7 mm. The radius of the central oscillator 2 is preferably 5 mm.

[0026] Preferably, the Archimedes spiral beam 3 rotates at an angle of 360 degrees.

[0027] The central oscillator 2 is located at the geometric center of the annular outer frame 1; The outer frame fan-shaped anchor point 4 is integrally formed on the inner edge of the annular outer frame 1, and the curvature of the outer edge of the outer frame fan-shaped anchor point 4 is the same as the curvature of the inner edge of the annular outer frame 1. The fan-shaped anchor point 5 of the oscillator is integrally formed on the outer edge of the central oscillator 2, and the inner edge curvature of the fan-shaped anchor point 4 of the outer frame is the same as the outer edge curvature of the central oscillator 2. The Archimedes spiral beam 3 is connected between the annular outer frame 1 and the central oscillator 2, with the first end of the Archimedes spiral beam 3 connected to the sector anchor point 4 of the outer frame and the second end connected to the sector anchor point 5 of the oscillator.

[0028] The present invention sets out a fan-shaped anchor point 4 on the outer frame that fits into the inner edge of the annular outer frame 1, and a fan-shaped anchor point 5 on the oscillator that fits into the inner edge of the central oscillator 2. This allows the two ends of the Archimedes spiral beam 3 to avoid direct connection between the spiral beam and the central oscillator 2, thus avoiding the formation of a slit 8 at the connection point, which would otherwise cause test errors and stress concentration.

[0029] The number of Archimedes spiral beams 3 is multiple; Multiple Archimedean spiral beams 3 are evenly distributed along the circumference of the annular outer frame 1; Correspondingly, the number of outer frame sector anchor points 4 and oscillator sector anchor points 5 correspond to the number of Archimedes spiral beams 3, respectively; Each Archimedes spiral beam 3 is connected between an outer frame sector anchor point 4 and a oscillator sector anchor point 5.

[0030] Each Archimedes spiral beam 3 is spatially non-overlapping and is independently set.

[0031] In one embodiment, the present invention provides three Archimedean spiral beams 3.

[0032] The number of chip structures 6 is two, and the functional surfaces of the two chip structures 6 are packaged face to face, with the functional surface being the side that can form the capacitor plate. Correspondingly, the MEMS-based capacitive laser power mirror also includes an insulating material ring 7; the insulating material ring 7 is located between the annular outer frame 1 of the two chip structures 6.

[0033] The insulating material ring 7 is made of polyimide ring with a thickness of 1900~2100μm, preferably 2000μm.

[0034] This invention also discloses a method for fabricating a capacitive laser power mirror based on MEMS technology, comprising the following steps: S1. Perform the first photolithography pattern on the front side of the silicon wafer to form the area of ​​the central oscillator 2, prepare a silver metal layer using magnetron sputtering, and form the reflective surface of the central oscillator 2 through a lift-off process; First, a 200μm thick intrinsically undoped double-polished silicon wafer was obtained as the substrate. Choosing intrinsically high-resistivity silicon is crucial, as its high resistance effectively prevents capacitive signals from being short-circuited by the conductive substrate, ensuring the integrity of the electrical signals. Simultaneously, the excellent mechanical properties of single-crystal silicon wafers provide an ideal foundation for realizing high-precision thin-walled structures, achieving a perfect balance between mechanical properties and microfabrication technology. Furthermore, silicon's high thermal conductivity facilitates rapid and uniform heat dissipation during processing and use, avoiding thermal stress drift caused by localized temperature rises and ensuring the stability of the sensor.

[0035] Next, the front-side metallization process begins, starting with photolithography: Photoresist is coated on the front side of the silicon wafer, and exposure and development are performed using a first mask to precisely form the area of ​​the central oscillator 2. Next, a layer of silver is deposited across the entire front side of the wafer using magnetron sputtering. Silver was chosen as the reflective mirror material because of its excellent optical properties of high reflectivity over a wide wavelength range and low absorption loss. These properties allow most of the energy of the incident laser to act as optical radiation pressure, thereby minimizing thermal absorption and reducing thermal noise interference.

[0036] After sputtering, acetone solvent is used for lift-off treatment to dissolve the photoresist in the unexposed areas, thereby removing the silver metal covering them. Finally, only the central oscillator area is retained to form a complete silver reflective mirror.

[0037] S2. Perform a second photolithography pattern on the front side of the wafer after the silver metal layer is prepared to form the region of Archimedes spiral beam 3, outer frame fan-shaped anchor point 4 and oscillator fan-shaped anchor point 5. Then, sputter chromium metal layer and copper metal layer in the spiral beam and fan-shaped anchor point regions, and form chromium / copper composite metal layer through a lift-off process. After completing the fabrication of the silver reflective mirror, the fabrication of the Archimedes spiral beam 3, the outer frame sector anchor point 4, and the oscillator sector anchor point 5 will continue: First, using the same photolithography process, a second photomask is used to form the pattern of the Archimedes spiral beam 3, the outer frame fan-shaped anchor point 4, and the oscillator fan-shaped anchor point 5.

[0038] Subsequently, a chromium (Cr) metal layer and a copper (Cu) metal layer are deposited sequentially by magnetron sputtering. In this structure, copper is used as the capacitor plate and interconnect wires due to its excellent conductivity; however, since the direct adhesion between copper and the silicon substrate is poor, a chromium metal layer is pre-sputtered between the copper layer and the silicon as an intermediate adhesion layer. This effectively avoids the problem of copper layer detachment in subsequent processes. After the metal layer deposition, an acetone stripping process is used again to remove the photoresist and any unwanted metal on it, thereby forming a complete and precise chromium / copper composite metal layer in the target area.

[0039] In this invention, the outer frame electrode leads are fabricated on the back side of the silicon wafer using the same process as the Archimedes spiral beam 3.

[0040] S3. Perform a third photolithography patterning on the front side of the silicon wafer after all metal layers have been prepared to form the chip structure 6 pattern. Use the silver metal layer and the chromium / copper composite metal layer as etching masks to perform dry etching on the silicon wafer to integrally form the chip structure 6, which includes the annular outer frame 1, the Archimedes spiral beam 3, the outer frame fan-shaped anchor point 4, the oscillator fan-shaped anchor point 5, and the central oscillator 2.

[0041] After all functional metal layers are fabricated in S2, chip structure 6 is released in S3.

[0042] First, through a third photolithography step, the overall structural pattern, including the Archimedes spiral beam 3, the outer frame fan-shaped anchor point 4, and the oscillator fan-shaped anchor point 5, is transferred onto the photoresist on the front side of the wafer.

[0043] Subsequently, using the previously prepared robust silver metal layer and chromium / copper composite metal layer as an etching mask, the silicon wafer was etched using a high-speed, high-precision dry etching process. This process selectively removes silicon not protected by the metal layer until the 200μm thick silicon wafer is completely etched through, thereby fabricating a high-precision suspended helical beam structure in one piece, successfully obtaining a complete capacitive sensor chip.

[0044] Following S3, it also includes: S4. Prepare another chip structure 6 according to steps S1-S3; S5. Place the two prepared chip structures 6 with the chromium / copper composite metal layer facing each other, and set an insulating material ring 7 between the annular outer frame 1 of the two chip structures 6; S6. Bond and encapsulate the two chips with the insulating material ring 7.

[0045] Finally, the chips are packaged to form a differential capacitive sensor. Two identical capacitive sensor chips prepared by the above method are taken and precisely placed face-to-face with the sides of the chips having the chromium / copper composite metal layer, i.e., the capacitor plates. A 2000μm thick polyimide ring is placed between the annular outer frame 1 of the two chips, and an insulating material ring 7 is used to precisely set and maintain a fixed spacing between the two plates. Subsequently, the two chips are bonded to the polyimide ring and packaged into a single unit.

[0046] This symmetrical dual-chip structure can offset the static displacement error of the central oscillator 2 caused by gravity. This is fundamentally different from the asymmetrical design of traditional capacitive pressure sensors, which uses a fixed electrode on one side and a movable electrode on the other. In traditional designs, the movable electrode will sag due to gravity, resulting in a smaller initial capacitance gap and introducing measurement errors. The symmetrical design of this invention fundamentally avoids this problem, significantly improving measurement accuracy and long-term stability.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A capacitive laser power mirror based on MEMS technology, characterized in that, include: Integrated chip structure (6); The chip structure (6) includes: an annular outer frame (1), a central oscillator (2), an outer frame sector anchor point (4), an oscillator sector anchor point (5), and an Archimedes spiral beam (3); The central oscillator (2) is located at the geometric center of the annular outer frame (1); The outer frame fan-shaped anchor point (4) is integrally formed on the inner edge of the annular outer frame (1), and the outer edge curvature of the outer frame fan-shaped anchor point (4) is the same as the inner edge curvature of the annular outer frame (1). The oscillator fan-shaped anchor point (5) is integrally formed on the outer edge of the central oscillator (2), and the inner edge curvature of the oscillator fan-shaped anchor point (5) is the same as the outer edge curvature of the central oscillator (2); The Archimedes spiral beam (3) is connected between the annular outer frame (1) and the central oscillator (2), and the first end of the Archimedes spiral beam (3) is connected to the fan-shaped anchor point (4) of the outer frame, and the second end is connected to the fan-shaped anchor point (5) of the oscillator.

2. The capacitive laser power mirror based on MEMS technology according to claim 1, characterized in that, The number of Archimedes spiral beams (3) is multiple; Multiple Archimedean spiral beams (3) are evenly distributed along the circumference of the annular outer frame (1); Correspondingly, the number of the outer frame sector anchor points (4) and the oscillator sector anchor points (5) are respectively corresponding to the number of the Archimedes spiral beams (3); Each Archimedes spiral beam (3) is connected between one of the outer frame sector anchor points (4) and one of the oscillator sector anchor points (5).

3. The capacitive laser power mirror based on MEMS technology according to claim 1 or 2, characterized in that, It also includes an insulating material ring (7); The number of chip structures (6) is two, and the functional surfaces of the two chip structures (6) are packaged face to face, and the functional surface is the side that can form a capacitor plate; The insulating material ring (7) is located between the annular outer frame (1) of the two chip structures (6).

4. The capacitive laser power mirror based on MEMS technology according to claim 1, characterized in that, The Archimedes spiral beam (3) has a rotation angle of 360 degrees.

5. The capacitive laser power mirror based on MEMS technology according to claim 1, characterized in that, The radius of the central oscillator (2) is 4~6mm.

6. The capacitive laser power mirror based on MEMS technology according to claim 1, characterized in that, The outer diameter of the annular outer frame (1) is 15~17mm and the inner diameter is 11~12mm.

7. The capacitive laser power mirror based on MEMS technology according to claim 3, characterized in that, The insulating material ring (7) is made of polyimide and has a thickness of 1900~2100μm.

8. A method for fabricating a capacitive laser power mirror based on MEMS technology as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. The first photolithography pattern is formed on the front side of the silicon wafer to form the area of ​​the central oscillator (2). A silver metal layer is prepared by magnetron sputtering and the reflective mirror of the central oscillator is formed by a lift-off process. S2. A second photolithography pattern is formed on the front side of the wafer after the silver metal layer is prepared, forming the region of Archimedes spiral beam (3), outer frame fan-shaped anchor point (4) and oscillator fan-shaped anchor point (5), and chromium metal layer and copper metal layer are sputtered sequentially in the spiral beam and fan-shaped anchor point regions, and a chromium / copper composite metal layer is formed by peeling process; S3. Perform a third photolithography pattern on the front side of the silicon wafer after all metal layers have been prepared to form a chip structure (6) pattern. Use the silver metal layer and chromium / copper composite metal layer as etching masks to perform dry etching on the silicon wafer to integrally form a chip structure (6) including an annular outer frame (1), an Archimedes spiral beam (3), an outer frame fan-shaped anchor point (4), an oscillator fan-shaped anchor point (5), and a central oscillator (2).

9. The method for fabricating a capacitive laser power mirror based on MEMS technology according to claim 8, characterized in that, Following S3, it also includes: S4. Prepare another chip structure (6) according to steps S1-S3. S5. Place the two prepared chip structures (6) with the chromium / copper composite metal layer facing each other, and set an insulating material ring (7) between the annular outer frame of the two chip structures (6). S6. Bond and encapsulate the two chips with an insulating material ring (7).

10. The method for fabricating a capacitive laser power mirror based on MEMS technology according to claim 8, characterized in that, The thickness of the silicon wafer is 180~200μm.

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