High-performance Z-axis accelerometer and preparation method thereof

Abstract

The invention provides a high-performance Z-axis accelerometer and a preparation method thereof, the high-performance Z-axis accelerometer comprises a movable electrode layer and two fixed electrode plates, and the two fixed electrode plates respectively cover two opposite sides of the movable electrode layer; the movable electrode layer comprises an electrode frame body and two sealed frame bodies, and one sealed frame body is arranged between each fixed electrode plate and the electrode frame body; the movable electrode layer further comprises a cantilever beam and a mass block, a closed frame structure is defined by the electrode frame, the cantilever beam and the mass block are both located on the inner side of the electrode frame, the two ends of the cantilever beam are connected with the electrode frame and the mass block respectively, and when the high-performance Z-axis accelerometer is in a non-acceleration state along the Z axis, a gap exists between each fixed electrode plate and the mass block. By arranging the sealing frame bodies on the two surfaces of the movable electrode layer, the parasitic capacitance of the chip can be remarkably reduced, and the process reliability is improved. By reasonably designing the structures of the mass block and the cantilever beam, the sensitivity and dynamic response characteristics of the chip are balanced, and the impact resistance of the structure is improved.

Description

Technical Field

[0001] The embodiments disclosed herein belong to the field of MEMS device technology, specifically relating to a high-performance Z-axis accelerometer and its fabrication method. Background Technology

[0002] Microelectromechanical accelerometers (MEMS) are inertial devices based on MEMS technology used to measure the linear acceleration of moving objects. They are characterized by small size, high reliability, low cost, and suitability for mass production, and are therefore widely used in consumer electronics, aerospace, automotive, medical equipment, and weaponry. However, existing accelerometer technologies suffer from high chip parasitic capacitance and poor manufacturing reliability. Summary of the Invention

[0003] The embodiments disclosed herein aim to at least solve one of the technical problems existing in the prior art, and provide a high-performance Z-axis accelerometer and its preparation method.

[0004] The first aspect of this disclosure provides a high-performance Z-axis accelerometer, which includes a movable electrode layer and two fixed electrode plates, the two fixed electrode plates respectively covering opposite sides of the movable electrode layer; The active electrode layer includes an electrode frame and two sealing frames, with a sealing frame provided between each fixed electrode plate and the electrode frame; The active electrode layer also includes a cantilever beam and a mass block. The electrode frame forms a closed frame structure. The cantilever beam and the mass block are both located inside the electrode frame. The two ends of the cantilever beam are respectively connected to the electrode frame and the mass block. When the high-performance Z-axis accelerometer is in a non-accelerating state along the Z-axis, there is a gap between each of the fixed electrode plates and the mass block.

[0005] In some embodiments of this disclosure, the active electrode layer includes two cantilever beams and two mass blocks. Each mass block is connected to the electrode frame via a corresponding cantilever beam. The two mass blocks are symmetrically arranged about the centerline of the electrode frame in the length direction, and each mass block is symmetrically arranged about the centerline of the electrode frame in the width direction.

[0006] In some embodiments of this disclosure, the sealing frame is made of BF33 glass.

[0007] In some embodiments of this disclosure, the end face of the sealing frame near the fixed electrode plate is on the same plane as the end face of the electrode frame near the fixed electrode plate.

[0008] In some embodiments of this disclosure, the thickness of the mass block is less than the thickness of the electrode frame.

[0009] In some embodiments of this disclosure, the electrode frame is arranged around the inner ring of the electrode frame, and the outer ring size of the electrode frame is the same as the outer ring size of the sealing frame.

[0010] In some embodiments of this disclosure, the active electrode layer includes an active outer electrode connected to the outside of the electrode frame, and the fixed electrode plate includes a fixed outer electrode located on the same side of the electrode frame as the active outer electrode, with the fixed outer electrode and the active outer electrode spaced apart.

[0011] The second aspect of this disclosure provides a method for fabricating a high-performance Z-axis accelerometer, a method for fabricating the high-performance Z-axis accelerometer described in any of the above embodiments, the method comprising: S100: Pretreatment of the fixed electrode plate and formation of the fixed external electrode; S200: Bonding of the silicon plate of the active electrode layer to the sealing frame of BF33 glass, corrosion of the electrode frame, cantilever beam and mass block of the active electrode layer; S300: Bond the active electrode layer and the fixed electrode plates on both sides thereof.

[0012] In some embodiments of this disclosure, S100 includes: S101: Apply adhesive to the front side of the silicon wafer; S102: Perform photolithography on the silicon wafer to expose the ear area; S103: Dry etching through the ear platform area to form a support base for fixing the external electrode; S104: Photolithography is performed again on the front side of the silicon wafer to sputter metal TiAu or metal Al onto the support substrate for fixing the external electrode to form the fixed external electrode; S105: Remove glue.

[0013] In some embodiments of this disclosure, S200 includes: S201: Photolithography is performed on both sides of the silicon wafer to pattern the area of ​​the sealing frame, thereby exposing the sealing frame area; S202: Dry etching on both sides of the silicon wafer, followed by removal of photoresist; S203: The silicon wafer is bonded to BF33 glass on both sides; S204: BF33 glass is refluxed at high temperature and filled into the groove of the sealing frame to form a sealing frame structure, and then double-sided grinding and polishing are performed. S205: A double-sided sputtered metal M1 layer on a silicon wafer, where the metal M1 is Cr or Au; S206: Patterned metal M1 layer, wet etching to form capacitor gaps; S207: Remove metal M1, pattern the double-sided sputtered metal M2 layer, and expose the mass block release area and the non-electrode area of ​​the earpiece. Metal M2 is Cr or Au. S208: Wet etching of the mass block release area and the non-electrode plate area of ​​the ear platform to a certain depth; S209: Re-pattern the metal M2 layer to expose the cantilever beam area; S210: Continue wet etching of the mass block release area, cantilever beam area and ear platform non-electrode plate area to form the ear platform of cantilever beam, mass block and movable external electrode; S211: Remove the metal M2 layer from both sides of the silicon wafer; S212: Metal is prepared on the earpiece using a stripping process to form a movable external electrode.

[0014] The high-performance Z-axis accelerometer and its fabrication method according to embodiments of this disclosure include two fixed electrode plates and a movable electrode layer. The two fixed electrode plates are bonded to opposite sides of the movable electrode layer. Specifically, the movable electrode layer includes an electrode frame and two sealing frames, which are respectively disposed on opposite sides of the electrode frame. Each side of the electrode frame is bonded to a fixed electrode plate via a corresponding sealing frame, thereby forming a closed space between the two fixed electrode plates and the electrode frame. By providing sealing frames on both sides of the movable electrode layer, the chip parasitic capacitance can be significantly reduced, process reliability improved, and it is suitable for mass production in engineering applications. Furthermore, the movable electrode layer also includes a cantilever beam and a mass block. The mass block is connected to the inner side of the electrode frame via the cantilever beam. The movable mass block, anchored by the cantilever beam, is sandwiched between the upper and lower fixed electrodes, forming a "sandwich" structure. When a high-performance Z-axis accelerometer accelerates along a sensitive axis perpendicular to the chip plane (such as the Z-axis), inertial force causes the mass block to shift, thereby changing the distance between the mass block and the upper and lower fixed electrode plates. This results in a change in the differential capacitance between the mass block and the fixed electrode plates on both sides. The change in this differential capacitance is measured by an integrated detection circuit and converted into an electrical signal (usually a voltage) corresponding to the magnitude and direction of the acceleration. By rationally designing the structure of the mass block and cantilever beam, the chip's sensitivity and dynamic response characteristics are balanced, and the structure's impact resistance is improved. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the assembly structure of the high-performance Z-axis accelerometer of the present invention; Figure 2 for Figure 1 The diagram shows the disassembled structure of the high-performance Z-axis accelerometer. Figure 3 for Figure 1 A cross-sectional view of the high-performance Z-axis accelerometer shown. Figure 4 for Figure 1 The diagram shows the structure of the fixed electrode plate. Figure 5 for Figure 1 The diagram shows the structure of the active electrode layer. Figure 6 for Figure 1 The diagram shows the state and capacitance of the high-performance Z-axis accelerometer when it generates acceleration along the Z-axis. Figure 7 This is a flowchart of the method for preparing the fixed electrode plate of the high-performance Z-axis accelerometer of the present invention; Figure 7 (a) is a structural diagram of step S101; Figure 7 (b) is a structural diagram of step S102; Figure 7 (c) is a structural diagram of step S103; Figure 7 (d) is a structural diagram of step S104; Figure 7 (e) is a structural diagram of step S105; Figure 8 for Figure 7 A schematic diagram of the fixed electrolytic plate prepared by the method shown. Figure 9 This is a flowchart of the method for fabricating the active electrode layer of the high-performance Z-axis accelerometer of the present invention; Figure 9 (a) is a structural diagram of step S201; Figure 9 (b) is a structural diagram of step S202; Figure 9 (c) is a structural diagram of step S203; Figure 9 (d) is a structural diagram of step S204; Figure 9 (e) is a structural diagram of step S205; Figure 9 (f) is a structural diagram of step S206; Figure 9 (g) is a structural diagram of step S207; Figure 9 (h) is a structural diagram of step S208; Figure 9 (i) is a structural diagram of step S209; Figure 9 (j) is a structural diagram of step S210; Figure 9 (k) is a structural diagram of step S211; Figure 9 (l) is a structural diagram of step S212; Figure 10 This is a bonding diagram of the high-performance Z-axis accelerometer of the present invention.

[0016] The labels in the attached diagram are as follows: 100. High-performance Z-axis accelerometer; 10. Fix the electrode plate; 11. Fix the external electrode; 20. Movable electrode layer; 21. Electrode frame; 22. Sealed frame; 23. Cantilever beam; 24. Mass block; 25. Movable external electrode. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining this disclosure and are not intended to limit the disclosure. The described embodiments are some, but not all, of the embodiments of this disclosure. Based on the described embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this disclosure.

[0018] like Figures 1 to 6 As shown, the first aspect of this disclosure provides a high-performance Z-axis accelerometer 100, which includes a movable electrode layer 20 and two fixed electrode plates 10, with the two fixed electrode plates 10 respectively covering opposite sides of the movable electrode layer 20. The movable electrode layer 20 includes an electrode frame 21 and two sealed frames 22. A sealed frame 22 is provided between each fixed electrode plate 10 and the electrode frame 21. The movable electrode layer 20 also includes a cantilever beam 23 and a mass block 24. The electrode frame 21 forms a closed frame structure. The cantilever beam 23 and the mass block 24 are both located inside the electrode frame 21. The two ends of the cantilever beam 23 are respectively connected to the electrode frame 21 and the mass block 24. When the high-performance Z-axis accelerometer 100 is in a non-accelerated state along the Z-axis, there is a gap between each fixed electrode plate 10 and the mass block 24.

[0019] The high-performance Z-axis accelerometer 100 according to an embodiment of this disclosure includes two fixed electrode plates 10 and a movable electrode layer 20. The two fixed electrode plates 10 are respectively bonded to opposite sides of the movable electrode layer 20. Specifically, the movable electrode layer 20 includes an electrode frame 21 and two sealing frames 22. The two sealing frames 22 are respectively disposed on opposite sides of the electrode frame 21. The two sides of the electrode frame 21 are respectively bonded to the fixed electrode plates 10 through corresponding sealing frames 22, so that the two fixed electrode plates 10 and the electrode frame 21 form a closed space. By providing sealing frames 22 on both sides of the movable electrode layer 20, the chip parasitic capacitance can be significantly reduced, the process reliability can be improved, and it is suitable for mass production of products.

[0020] In addition, the movable electrode layer 20 also includes a cantilever beam 23 and a mass block 24. The mass block 24 is connected to the inner side of the electrode frame 21 via the cantilever beam 23. The movable mass block 24, anchored by the cantilever beam 23, is sandwiched between the upper and lower fixed electrodes, forming a "sandwich" structure. When the high-performance Z-axis accelerometer 100 accelerates along a sensitive axis perpendicular to the chip plane (such as the Z-axis) (e.g., ... Figure 6As shown, inertial force causes the mass block 24 to shift, thereby changing the distance between the mass block 24 and the two fixed electrode plates 10. For example, the distance between the mass block 24 and one fixed electrode plate 10 increases, while the distance between the mass block 24 and the fixed electrode plate 10 on the other side decreases. This causes a change in the differential capacitance between the mass block 24 and the two fixed electrode plates 10. The change in this differential capacitance is measured by an integrated detection circuit and converted into an electrical signal (usually a voltage) corresponding to the magnitude and direction of the acceleration. By rationally designing the structure of the mass block 24 and the cantilever beam 23, the chip sensitivity and dynamic response characteristics are balanced, and the structural impact resistance is improved.

[0021] In some embodiments of this disclosure, the active electrode layer 20 includes two cantilever beams 23 and two mass blocks 24. Each mass block 24 is connected to the electrode frame 21 via a corresponding cantilever beam 23. The two mass blocks 24 are symmetrically arranged about the centerline of the electrode frame 21 in the length direction and about the centerline of the electrode frame 21 in the width direction. The two symmetrically arranged mass blocks 24 improve the symmetry of the active electrode layer 20, offsetting non-uniform stress caused by process errors, and improving the device's zero-bias and temperature stability while reducing the chip's cross-axis sensitivity.

[0022] In some embodiments of this disclosure, the sealing frame 22 is made of BF33 glass, the silicon electrode frame 21 is bonded to the BF33 glass sealing frame 22, and the silicon fixed electrode plate 10 is bonded to the BF33 glass sealing frame 22.

[0023] In some embodiments of this disclosure, the end face of the sealing frame 22 near the fixed electrode plate 10 is flush with the end face of the electrode frame 21 near the fixed electrode plate 10. That is, the movable electrode layer 20 is bonded to the fixed electrode plate 10 through the sealing frame 22.

[0024] In some embodiments of this disclosure, two sealing frames 22 are respectively embedded in opposite sides of the electrode frame 21 to ensure the reliability of the connection between the electrode frame 21 and the sealing frame 22.

[0025] In some embodiments of this disclosure, the overall thickness of the embedded structure formed by the two sealing frames 22 and the electrode frame 21 is greater than the thickness of the mass block 24, so as to ensure that there are movable gaps between the two sides of the mass block 24 and the two fixed electrode plates 10.

[0026] In other embodiments of this disclosure, a receiving groove for accommodating the movable mass block 24 may be provided on the fixed electrode plate 10. In this case, the overall thickness of the embedded structure formed by the two sealing frames 22 and the electrode frame 21 may be equal to the thickness of the mass block 24.

[0027] In some embodiments of this disclosure, the electrode frame 21 is arranged around the inner ring of the electrode frame 21, and the outer ring size of the electrode frame 21 is the same as the outer ring size of the sealing frame 22, so that the sealing frame 22 can isolate the electrode frame 21 and fix the electrode plate 10, while reducing the volume and weight of the sealing frame 22.

[0028] In some embodiments of this disclosure, the movable electrode layer 20 includes a movable outer electrode 25 connected to the outside of the electrode frame 21, and the fixed electrode plate 10 includes a fixed outer electrode 11. The fixed outer electrode 11 and the movable outer electrode 25 are located on the same side of the electrode frame 21 and are spaced apart. Specifically, along the width direction of the electrode frame 21, one fixed outer electrode 11, one movable outer electrode 25, and another fixed outer electrode 11 are sequentially spaced apart.

[0029] In the embodiments of this disclosure, the fixed electrode plate 10 is a rectangular plate structure, and a fixed external electrode 11 is provided on one side of the fixed electrode plate 10. The electrode frame 21 and the sealing frame 22 are both rectangular frame structures. On the plane perpendicular to the thickness direction of the fixed electrode plate 10, the outer edge of the sealing frame 22 and the outer edge of the electrode frame 21 coincide with the rectangular edge contour of the fixed electrode plate 10. The two fixed electrode plates 10 respectively cover the two sides of the electrode frame 21, and the two fixed electrode plates 10 are respectively bonded to the electrode frame 21 through the two sealing frames 22, so that the two fixed electrode plates 10 and the electrode frame 21 together form a closed space to accommodate the mass block 24 and the cantilever beam 23.

[0030] It should be noted that the inner side of the electrode frame 21 refers to one side of the rectangular space enclosed by the rectangular frame, and the outer side of the electrode frame 21 refers to the side of the rectangular frame facing away from the rectangular space.

[0031] like Figures 7 to 10 As shown, the second aspect of this disclosure provides a method for fabricating a high-performance Z-axis accelerometer 100, a method for fabricating the high-performance Z-axis accelerometer 100 described in any of the above embodiments, the method comprising: S100: Pretreatment of the fixed electrode plate 10 and formation of the fixed external electrode 11; S200: The silicon plate of the active electrode layer 20 is bonded to the sealing frame 22 of BF33 glass, and the electrode frame 21, cantilever beam 23 and mass block 24 of the active electrode layer 20 are corroded. S300: Bond the active electrode layer 20 and the fixed electrode plates 10 on both sides thereof.

[0032] According to the fabrication method of the high-performance Z-axis accelerometer 100 according to the embodiments of this disclosure, by setting a sealing frame 22 on both sides of the active electrode layer 20, the parasitic capacitance of the chip can be significantly reduced, the process reliability can be improved, and it is suitable for mass production of products. By rationally designing the structure of the mass block 24 and the cantilever beam 23, the chip sensitivity and dynamic response characteristics are balanced, and the structural impact resistance is improved.

[0033] In some embodiments of this disclosure, S100 includes: S101: Apply a uniform coating (e.g., to the front side of the silicon wafer used to prepare the fixed electrode plate 10) Figure 7 (as shown in a) S102: Photolithography is performed on the silicon wafer to expose the Si in the non-electrode areas, i.e., the Si in the ear-shaped areas (e.g., ...). Figure 7 (as shown in b) S103: Dry etching through the exposed Si in the ear-shaped area forms the silicon support substrate for fixing the external electrode 11. That is, the portion of the ear-shaped area used to fabricate the fixing electrode plate 10, i.e., the silicon support substrate, is retained, while the remaining portion of the ear-shaped area is removed (e.g., ...). Figure 7 As shown in c and Figure 8 (as shown) S104: Photolithography is performed again on the front side of the silicon wafer to sputter TiAu or Al metal onto the fixed external electrode 11, forming a metal layer on the silicon support substrate, i.e., forming the fixed external electrode (e.g., ...). Figure 7 (as shown in d) S105: Remove adhesive to obtain the structure where electrode plate 10 is connected to fixed external electrode 11 (e.g., ...). Figure 7 As shown in e and as Figure 8 (As shown).

[0034] In some embodiments of this disclosure, S200 includes: S201: Photolithography is performed on both sides of the silicon wafer used to fabricate the active electrode layer 20 to expose the area corresponding to the sealing frame 22 (e.g., Figure 9 (as shown in a) S202: Double-sided dry etching of the silicon surface to a depth of 90-110μm, preferably 100μm, to form an annular groove accommodating the sealing frame 22, followed by removal of the photoresist (e.g., Figure 9 (as shown in b) S203: The silicon wafer with double-sided Si is anoly bonded to a BF33 glass plate (e.g., ...). Figure 9 (as shown in c) S204: BF33 glass is melted at high temperature and refluxed to fill the annular groove accommodating the sealing frame 22, forming the sealing frame 22 structure, and then double-sided grinding and polishing (e.g., Figure 9 (as shown in d) S205: A double-sided sputtered metal M1 layer is deposited on a silicon wafer to serve as a hard mask for subsequent wet etching. Metal M1 is Cr or Au (e.g., ...). Figure 9 (as shown in e) S206: Pattern the mask metal M1 layer to expose the non-annular groove area, wet-etch the silicon wafer in the non-annular groove area to a depth of 1.5~2.5μm, preferably 2μm, to form a capacitor gap (e.g. Figure 9 (as shown in f) S207: After removing metal M1, patterning is performed by double-sided sputtering of metal M2 layers to expose the mass release area and the non-electrode area of ​​the earpiece. Metal M2 is Cr or Au (e.g., Cr or Au). Figure 9 (as shown in g); S208: Wet corrosion mass block release area and ear platform non-electrode plate area to a certain depth (e.g. Figure 9 (as shown in h) S209: Re-pattern the metal M2 layer to expose the cantilever beam area (e.g., Figure 9 (as shown in i) S210: Continue wet etching of the mass block release area, cantilever beam area, and ear platform non-electrode plate area to form the ear platform (e.g., cantilever beam 23, mass block 24, and movable external electrode 25). Figure 9 j) S211: Remove metal M2 from both sides (e.g.) Figure 9 (as shown in k); S212: Metal is prepared in the earpiece area using a lift-off process; TiAu or Al can be selected to form the movable external electrode (e.g., Figure 9 (as shown in l).

[0035] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A high-performance Z-axis accelerometer, characterized in that, The high-performance Z-axis accelerometer includes a movable electrode layer and two fixed electrode plates, with the two fixed electrode plates respectively covering opposite sides of the movable electrode layer; The active electrode layer includes an electrode frame and two sealing frames, with a sealing frame provided between each fixed electrode plate and the electrode frame; The active electrode layer also includes a cantilever beam and a mass block. The electrode frame forms a closed frame structure. The cantilever beam and the mass block are both located inside the electrode frame. The two ends of the cantilever beam are respectively connected to the electrode frame and the mass block. When the high-performance Z-axis accelerometer is in a non-accelerating state along the Z-axis, there is a gap between each of the fixed electrode plates and the mass block.

2. The high-performance Z-axis accelerometer according to claim 1, characterized in that, The active electrode layer includes two cantilever beams and two mass blocks. Each mass block is connected to the electrode frame through a corresponding cantilever beam. The two mass blocks are symmetrically arranged about the centerline of the electrode frame in the length direction and about the centerline of the electrode frame in the width direction.

3. The high-performance Z-axis accelerometer according to claim 1, characterized in that, The sealing frame is made of BF33 glass.

4. The high-performance Z-axis accelerometer according to claim 1, characterized in that, The end face of the sealing frame near the fixed electrode plate is on the same plane as the end face of the electrode frame near the fixed electrode plate.

5. The high-performance Z-axis accelerometer according to claim 1, characterized in that, The thickness of the mass block is less than the thickness of the electrode frame.

6. The high-performance Z-axis accelerometer according to claim 1, characterized in that, The electrode frame is arranged around the inner ring of the electrode frame, and the outer ring size of the electrode frame is the same as the outer ring size of the sealing frame.

7. The high-performance Z-axis accelerometer according to claim 1, characterized in that, The movable electrode layer includes a movable outer electrode, which is connected to the outside of the electrode frame. The fixed electrode plate includes a fixed outer electrode, which is located on the same side of the electrode frame as the movable outer electrode. The fixed outer electrode and the movable outer electrode are spaced apart.

8. A method for preparing a high-performance Z-axis accelerometer, used to prepare the high-performance Z-axis accelerometer according to any one of claims 1 to 7, characterized in that, The method includes: S100: Pretreatment of the fixed electrode plate and formation of the fixed external electrode; S200: Bonding of the silicon plate of the active electrode layer to the sealing frame of BF33 glass, corrosion of the electrode frame, cantilever beam and mass block of the active electrode layer; S300: Bond the active electrode layer and the fixed electrode plates on both sides thereof.

9. The method for preparing a high-performance Z-axis accelerometer according to claim 8, characterized in that, S100 includes: S101: Apply adhesive to the front side of the silicon wafer; S102: Perform photolithography on the silicon wafer to expose the ear area; S103: Dry etching through the ear platform area to form a support base for fixing the external electrode; S104: Photolithography is performed again on the front side of the silicon wafer to sputter metal TiAu or metal Al onto the support substrate for fixing the external electrode to form the fixed external electrode; S105: Remove glue.

10. The method for preparing a high-performance Z-axis accelerometer according to claim 8, characterized in that, S200 includes: S201: Photolithography is performed on both sides of the silicon wafer to pattern the area of ​​the sealing frame, thereby exposing the sealing frame area; S202: Dry etching on both sides of the silicon wafer, followed by removal of photoresist; S203: The silicon wafer is bonded to BF33 glass on both sides; S204: BF33 glass is refluxed at high temperature and filled into the groove of the sealing frame to form a sealing frame structure, and then double-sided grinding and polishing are performed. S205: A double-sided sputtered metal M1 layer on a silicon wafer, where the metal M1 is Cr or Au; S206: Patterned metal M1 layer, wet etching to form capacitor gaps; S207: Remove metal M1, pattern the double-sided sputtered metal M2 layer, and expose the mass block release area and the non-electrode area of ​​the earpiece. Metal M2 is Cr or Au. S208: Wet etching of the mass block release area and the non-electrode plate area of ​​the ear platform to a certain depth; S209: Re-pattern the metal M2 layer to expose the cantilever beam area; S210: Continue wet etching of the mass block release area, cantilever beam area and ear platform non-electrode plate area to form the ear platform of cantilever beam, mass block and movable external electrode; S211: Remove the metal M2 layer from both sides of the silicon wafer; S212: Metal is prepared on the earpiece using a stripping process to form a movable external electrode.

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