Inertial sensor and manufacturing method

Abstract

The present invention provides an inertial sensor and a manufacturing method. The manufactured inertial sensor comprises a base body structure and a movable inertial structure arranged at one side of the base body structure and spaced apart from same; the base body structure comprises a base layer, a circuit layer attached to the side of the base layer close to the movable inertial structure, and a blocking structure arranged on the circuit layer; the blocking structure is made of an insulating material; a plurality of slots running through in the thickness direction are formed in the circuit layer; the blocking structure comprises a plurality of protruding blocks which are connected to the circuit layer and protrude from the surface of the circuit layer facing away from the base layer; and the slots are blocked by insertion of the protruding blocks in a one-to-one manner. The inertial sensor has the advantages of reducing likeliness of viscosity, having a stable structure, and having a small limitation on the minimum size of the base body structure and the movable inertial structure, thereby facilitating improvement of the final performance of the inertial sensor.

Description

Inertial sensor and preparation method Technical Field

[0001] The present invention belongs to the technical field of sensors, and in particular relates to an inertial sensor and a preparation method thereof. Background Art

[0002] An inertial sensor is a device used to detect and measure acceleration, tilt, impact, vibration, etc. It is often used to measure the acceleration of a car and the tilt angle of an electronic terminal.

[0003] A MEMS inertial sensor generally includes a base structure and a movable inertial structure spaced apart from one side of the base structure. The base structure is provided with a circuit layer. During operation of the inertial sensor, the gap between the movable inertial structure and the base structure changes.

[0004] In some cases, the movable inertial structure and the base structure surface may come into contact, resulting in a static friction failure mode. Under the action of friction, the underlying material is easily exposed to the air gap and affected and falls off, making the base structure unstable during sensor operation, thereby negatively affecting the ultimate performance of the inertial sensor. Technical issues

[0005] The object of the present invention is to provide an inertial sensor and a preparation method thereof, which can avoid material loss in the base structure and help improve the final performance of the inertial sensor. Technical Solutions

[0006] To solve the above-mentioned technical problems, the present invention is implemented as follows: an inertial sensor is provided, comprising a base structure and a movable inertial structure spaced apart on one side of the base structure; the base structure comprises a base layer, a circuit layer attached to the base layer and adjacent to the movable inertial structure, and a blocking structure disposed on the circuit layer; the blocking structure is made of an insulating material; the circuit layer has a plurality of holes extending through the circuit layer in the thickness direction; the blocking structure comprises a plurality of bumps connected to the circuit layer and protruding from a surface of the circuit layer facing away from the base layer; the bumps are embedded and sealed one by one in the holes.

[0007] Furthermore, the blocking structure further includes a plurality of protrusions, one end of each of the protrusions is only connected to the surface of the circuit layer away from the base layer.

[0008] Furthermore, the bump embedded in the hole includes an embedded portion located inside the hole and a side edge portion connected to the top side of the embedded portion and extending along the surface of the circuit layer away from the base layer.

[0009] Furthermore, among the protrusions, at least some of the protrusions are provided with a groove facing the hole on a side away from the base layer.

[0010] Furthermore, the barrier structure is made of silicon nitride or silicon dioxide.

[0011] Furthermore, the inertial sensor also includes a first substrate arranged on a side of the base layer away from the circuit layer and a second substrate arranged on a side of the movable inertial structure away from the base structure, and a clearance groove is provided on a side of the second substrate facing the movable inertial structure.

[0012] Furthermore, the movable inertial structure includes an insulating layer stacked on the circuit layer, a sensing layer stacked on the insulating layer, a first bonding ring provided on the sensing layer, and a pin structure provided on the sensing layer;

[0013] A second engaging ring surrounding the outer circumference of the clearance groove is provided on the bottom side of the second substrate. The position of the second engaging ring corresponds to that of the first engaging ring and the second engaging ring is bonded to form a whole.

[0014] Furthermore, the middle area of ​​the sensing layer is a mass block structure for sensing motion, and a pressure point is provided at a position of the sensing layer corresponding to the position of the pin structure. The pressure point is separated from the mass block structure, and the pin structure is electrically connected to the circuit layer through the pressure point.

[0015] Furthermore, a method for preparing an inertial sensor is provided, comprising the following steps:

[0016] A base layer, a circuit layer attached to the base layer, and a blocking structure connected to the circuit layer are formed on one side of a first substrate, wherein the blocking structure is made of an insulating material, the circuit layer has a hole extending through the circuit layer in the thickness direction, and the blocking structure includes a plurality of bumps connected to the circuit layer and protruding from a surface of the circuit layer facing away from the base layer, wherein the bumps are embedded and blocked in the hole;

[0017] forming a movable inertial structure on a side of the circuit layer facing away from the base layer;

[0018] A second substrate having a relief groove on one side is provided, and the second substrate is bonded to a side of the circuit layer facing away from the base layer, with the relief groove facing the movable inertial structure.

[0019] Furthermore, the base layer, the circuit layer attached to the base layer, and the blocking structure connected to the circuit layer are formed on one side of the first substrate, including:

[0020] providing a first substrate;

[0021] forming a base layer on one side of the first substrate;

[0022] forming a conductive layer on a side of the base layer away from the first substrate, and removing part of the conductive layer to form a through-hole in the thickness direction to obtain the circuit layer;

[0023] An insulating layer is covered on the side of the circuit layer away from the base layer, and the insulating layer is filled in the hole groove; and part of the material of the insulating layer is removed to obtain the blocking structure.

[0024] Furthermore, the removing of part of the material of the insulating layer to obtain the blocking structure includes:

[0025] forming a barrier layer on a surface of the insulating layer;

[0026] performing patterning on the barrier layer to expose areas where the insulating layer material needs to be removed;

[0027] The insulating layer material in the area to be removed is removed by etching to obtain the blocking structure.

[0028] Furthermore, the step of removing the insulating layer material in the area to be removed by etching includes:

[0029] The etching speed is controlled, and the etching is stopped when the bottom of the etching area is flush with the surface of the circuit layer facing away from the base layer. Beneficial effects

[0030] The beneficial effects of the present invention are as follows: by embedding the bumps in the blocking structure into the holes and grooves of the circuit layer, the material at the bottom of the circuit layer can be isolated, there will be no film loss under the circuit layer, and the structure can remain stable; moreover, the bumps are connected to the circuit layer and the base layer at the same time, and the bumps can be more stably connected to the circuit layer, which helps to increase the shear strength of the blocking structure and thus prevent it from being peeled off; in addition, under the premise of improving the stability of the base structure, the restriction on the minimum characteristic size of the base structure can be reduced, and there is no need to set a blocking structure on the bottom side of the movable inertial structure, which can reduce the restriction on the minimum characteristic size of the movable inertial structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic diagram of the structure of an inertial sensor according to a first embodiment of the present invention;

[0032] FIG2 is a schematic cross-sectional view of a first type of bump in the inertial sensor structure of the present invention;

[0033] FIG3 is a schematic cross-sectional view of a second type of bump in the inertial sensor structure of the present invention;

[0034] FIG4 is a schematic diagram of the structure of an inertial sensor according to a second embodiment of the present invention;

[0035] FIG5 is a flow chart of a method for preparing an inertial sensor according to the present invention;

[0036] 6-14 are schematic structural diagrams of each step of the preparation process of the inertial sensor according to the first embodiment of the present invention;

[0037] 15-23 are schematic structural diagrams of each step of the preparation process of the inertial sensor according to the second implementation of the present invention. Modes for Carrying Out the Invention

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] In conjunction with Figures 1-4, an inertial sensor is provided, including a base structure 1 and a movable inertial structure 2 spaced apart from one side of the base structure 1. The base structure 1 includes a base layer 11, a circuit layer 12 attached to the base layer 11 on a side close to the movable inertial structure 2, and a blocking structure 13 disposed on the circuit layer 12. The blocking structure 13 is made of an insulating material. The circuit layer 12 has a plurality of holes 121 extending through the circuit layer 12 in the thickness direction. The blocking structure 13 includes a plurality of bumps 131 connected to the circuit layer 12 and protruding from a surface of the circuit layer 12 facing away from the base layer 11. The holes 121 are each embedded and sealed by the bumps 131.

[0040] By embedding the bump 131 in the blocking structure 13 into the hole 121 of the circuit layer 12, the material at the bottom of the circuit layer 12 can be isolated, there will be no film loss under the circuit layer 12, and the structure can remain stable; moreover, the bump 131 is connected to the circuit layer 12 and the base layer 11 at the same time, and the bump 131 can be more stably connected to the circuit layer 12, which helps to increase the shear strength of the blocking structure 13 and prevent it from being peeled off; in addition, under the premise of improving the stability of the base structure 1, the restriction on the minimum characteristic size of the base structure 1 can be reduced, and there is no need to set the blocking structure 13 on the bottom side of the movable inertial structure 2, which can reduce the restriction on the minimum characteristic size of the movable inertial structure 2.

[0041] It should be understood that in this solution, the bumps 131 are spaced apart from each other and are not connected as a whole. In this way, the blocking structure 13 is in the form of small-area dispersed bumps 131 rather than a large-area thin film covering, which cuts off the influence of the film stress on the entire inertial sensor and reduces the overall warping of the base structure 1.

[0042] In one embodiment, as shown in FIG1 , the blocking structure 13 further includes a plurality of protrusions 132 , one end of each of which is connected only to the surface of the circuit layer 12 facing away from the base layer 11 and is cylindrical in shape. Specifically, the protrusions 132 connected only to the surface of the circuit layer 12 facing away from the base layer 11 can all be cylindrical, regular prism-shaped, or ring-shaped with equal height, and can be evenly arranged, such as in a rectangular array or a circular array, with equal spacing between adjacent protrusions 132. This can effectively prevent the movable inertial structure 2 from adhering to the circuit layer 12 and reduce sticking. Preferably, the cylindrical protrusions 132 are arranged to face the central region of the movable inertial structure 2, and the remaining protrusions 132 embedded in the holes 121 are located around the central region.

[0043] Furthermore, the hole groove 121 is an annular concave structure and is coaxial with the circuit layer 12. The widths of adjacent hole grooves 121 can be the same or different and are not limited here. The circuit layer 12 is made of a conductive material, such as polysilicon. The bump 131 embedded in the hole groove 121 is an annular structure adapted to the hole groove 121, including an embedded portion 1313 located inside the hole groove 121 and a side edge portion 1311 extending along the surface of the circuit layer 12 away from the base layer 11, thereby sealing the hole groove 121 and maintaining the integrity and stability of the base layer 11 during the molding process of the inertial sensor. The bump 131 embedded in the hole groove 121 can improve the shear strength, and the side edge portion 1311 is close to the circuit layer 12, which is conducive to dispersing the large interaction stress between different materials and preventing the bump 131 from falling off. This structure has no restrictions on the structure of the circuit layer 12 and the movable inertial structure 2, can minimize the feature size and bring more room for device performance improvement.

[0044] In one embodiment, as shown in Figures 1-4, all the bumps 131 are embedded in the hole groove 121. In this way, each bump 131 can be stably connected to the circuit layer 12 to avoid being peeled off. At least part of the bumps 131 are provided with a groove 1312 facing the hole groove 121 on the side facing away from the base layer 11. Specifically, the cross-section of the bump 131 facing the central area of ​​the movable inertial structure 2 is T-shaped, and the part surrounding the central area is concave (that is, the side facing away from the base layer 11 is provided with a groove 1312 facing the hole groove 121) or T-shaped.

[0045] It should be understood that whether the bump 131 is embedded in the circuit layer 12, whether the bump 131 is T-shaped or concave-shaped, and the distribution of the bump 131 can be adaptively adjusted according to actual conditions, as long as the base layer 11 at the bottom of the circuit layer 12 can be isolated and some of the bumps 131 are connected to the circuit layer 12 and the base layer 11 at the same time.

[0046] Furthermore, the blocking structure 13 is made of insulating materials such as silicon nitride or silicon dioxide, so that even if the blocking structure 13 contacts the movable inertial structure 2 , no short circuit will occur.

[0047] Furthermore, the inertial sensor also includes a first substrate 3 arranged on the side of the base layer 11 facing away from the circuit layer 12 and a second substrate 4 arranged on the side of the movable inertial structure 2 facing away from the base structure 1, and a clearance groove 41 is provided on the side of the second substrate 4 facing the movable inertial structure 2. The first substrate 3 is a semiconductor substrate, such as a silicon substrate. In this embodiment, the first substrate 3 is circular, and the shape of the base layer 11 is adapted to the shape of the first substrate 3. The base layer 11 is used to support the circuit layer 12 and isolate the circuit layer 12 from the first substrate 3. In one embodiment, the base layer 11 is made of a material including silicon dioxide. Those skilled in the art should know that the first substrate 3 can also be other shapes, such as square, hexagonal, etc., and are not limited here.

[0048] Furthermore, the movable inertial structure 2 includes an insulating layer 21 stacked on the circuit layer 12 , a sensing layer 22 stacked on the insulating layer 21 , a first bonding ring 23 disposed on the sensing layer 22 , and a pin structure 24 disposed on the sensing layer 22 .

[0049] The sensing layer 22 is made of a conductive material, such as polycrystalline silicon. A through-hole 221 is provided in the middle region of the sensing layer 22 in the thickness direction. The through-hole 221 is an annular structure surrounding its central axis and is arranged radially with multiple through-holes 221 spaced apart. Adjacent through-holes 221 can have the same or different widths. Therefore, the middle region of the sensing layer 22 contains a mass block structure 201 for sensing motion. As the mass block structure 201 moves, the spacing between it and the circuit layer 12 changes, thereby detecting capacitance signals in the corresponding direction and achieving inertia detection. The deflection of the sensing layer 22 is parabolic, with the deflection being greatest at the center and smallest at the edge. Therefore, placing the mass block structure 201 at the location where the sensing layer 22 moves most violently, i.e., at the center of the sensing layer 22, can improve the sensitivity of the inertial sensor.

[0050] The first bonding ring 23 is annular and is stacked on top of the sensing layer 22. The second substrate 4 is a semiconductor substrate, such as a silicon substrate. The second substrate 4 is circular, but can also be other shapes, such as square, pentagon, hexagon, etc.

[0051] The bottom side of the second substrate 4 is provided with a clearance groove 41 and a second engaging ring 42 surrounding the outer circumference of the clearance groove 41. The position of the second engaging ring 42 corresponds to the position of the first engaging ring 23, and the second engaging ring 42 and the first engaging ring 23 are bonded together. In this way, a closed space is formed between the first substrate 3 and the second substrate 4. The internal structure of the inertial sensor can prevent interference from the external environment, which is conducive to controlling the air pressure in the closed space, thereby improving working stability.

[0052] A pressure point 25 is provided at a position corresponding to the position of the sensing layer 22 and the pin structure 24. The pressure point 25 is separated from the mass block structure 201. The pin structure 24 is electrically connected to the circuit layer 12 through the pressure point 25. The pin structure 24 is used for subsequent packaging and wiring. The pin structure 24 and the first bonding ring 23 can be formed using the same process.

[0053] Furthermore, in conjunction with FIG5 , this embodiment provides a method for preparing any of the above inertial sensors, comprising the following steps:

[0054] S100: Forming a base layer 11, a circuit layer 12 attached to the base layer 11, and a blocking structure 13 connected to the circuit layer 12 on one side of the first substrate 3. The blocking structure 13 is made of an insulating material. The circuit layer 12 has a hole 121 extending through the circuit layer 12 in the thickness direction. The blocking structure 13 includes a plurality of bumps 131 connected to the circuit layer 12 and protruding from a surface of the circuit layer 12 facing away from the base layer 11. The hole 121 is sealed by embedding one end of the bump 131.

[0055] S200 , forming a movable inertial structure 2 on a side of the circuit layer 12 facing away from the base layer 11 ;

[0056] S300 , providing a second substrate 4 having a clearance groove 41 on one side, and bonding the second substrate 4 to the side of the circuit layer 12 facing away from the base layer 11 , with the clearance groove 41 facing the movable inertial structure 2 .

[0057] In step S100, the following steps are specifically included:

[0058] As shown in FIG6 or 15 , a first substrate 3 is provided; the first substrate 3 can be made of a silicon nitride substrate, a silicon carbide substrate, a silicon substrate, or the like;

[0059] As shown in FIG7 or FIG16 , a base layer 11 is formed on one side of the first substrate 3 ; the base layer 11 may be made of materials such as silicon dioxide and silicon nitride; and the base layer 11 may be formed by deposition.

[0060] A conductive layer is formed on the side of the base layer 11 away from the first substrate 3, and part of the material of the conductive layer is removed to form a through hole 121 in the thickness direction to obtain the circuit layer 12; specifically, the conductive layer can be formed on the base layer 11 by deposition, and then an anti-etching layer is formed on the surface of the conductive layer by deposition, the anti-etching layer is patterned by a photolithography process to form a mask, and then the conductive layer is etched through the mask to form a through hole 121, thereby obtaining the circuit layer 12.

[0061] As shown in Figures 8 or 17 , a layer of insulating material is formed on the side of the circuit layer 12 facing away from the base layer 11, and the insulating material layer fills the hole groove 121; a portion of the insulating material layer is removed to obtain the blocking structure 13. Specifically, in this embodiment, the insulating material layer is made of gallium nitride. The gallium nitride insulating material layer can be grown on the side of the circuit layer 12 facing away from the base layer 11 using a deposition method such as hydride vapor phase epitaxy (HVPE), molecular beam epitaxy (MBE), or metal organic chemical vapor deposition (MOCVD). In this way, gallium nitride can fill the hole groove 121 of the circuit layer 12 and cover the surface of the circuit layer 12 facing away from the base layer 11.

[0062] Removing part of the insulating material layer to obtain the blocking structure 13 may include:

[0063] forming a barrier layer on the surface of the insulating material layer; specifically, the barrier layer may be formed by coating a photoresist on the surface of the insulating material layer;

[0064] The barrier layer is patterned to expose the area to be removed where the insulating material layer is to be removed. The patterning process is to expose and develop the barrier layer, wherein the area to be removed covers the gaps between the protrusions of the barrier structure 13 and also covers the grooves 1312 corresponding to the tops of the protrusions.

[0065] The insulating material in the area to be removed is removed by etching to obtain the blocking structure 13. Specifically, dry etching can be used as the etching method, and the etching speed is controlled. When the bottom of the etched area is flush with the surface of the circuit layer 12 facing away from the base layer 11, the etching is stopped. In this way, on the one hand, the insulating material layer between adjacent protrusions can be removed, so that the protrusions are spaced from each other rather than integrated, and on the other hand, a groove 1312 can be formed at one end of the corresponding protrusion, facing the hole 121, and the bottom end of the groove 1312 is flush with the surface of the circuit layer 12.

[0066] It should be understood that the barrier layer can be removed by cleaning after the barrier structure 13 is formed.

[0067] Depending on the shape of the blocking structure 13 to be formed, the mask pattern used in forming the circuit layer 12 in this step and the pattern formed by the patterning process when etching to form the blocking structure can be adaptively adjusted according to actual conditions. Therefore, the blocking structures 13 of different structures differ only in the patterns of these two steps, and the process steps remain the same. For example, the inertial sensors shown in Figures 1 and 4 are respectively produced by the preparation processes of Figures 5 and 6, where only the patterns of the two steps differ. In the first embodiment, the mask pattern used in forming the circuit layer 12 does not expose the conductive layer in the middle, so the central region does not form the aperture 121. In the second embodiment, the mask pattern used in forming the circuit layer 12 does expose the conductive layer in the middle, so the aperture 121 is formed. The pattern formed by the patterning process when etching to form the blocking structure differs in size and position between the two embodiments.

[0068] Furthermore, as shown in FIG. 9 or 18 , in step S200 , the movable inertial structure 2 may be formed by combining vapor phase epitaxy, vapor phase deposition, and photolithography processes.

[0069] Specifically, an insulating layer 21 is first formed on the circuit layer 12 by deposition, and then a sensing layer 22 is deposited on the insulating layer 21. An anti-etching layer is formed by deposition on the surface of the sensing layer 22. The anti-etching layer is patterned by a photolithography process to form a mask, and the sensing layer 22 is etched through the mask to form a through-hole 221.

[0070] The insulating layer 21 has a cavity 202 inside, which can be formed by etching the insulating layer 21 with gaseous hydrofluoric acid. Since the blocking structure 13 is on the circuit layer 12 and covers the hole 121, it can prevent the gaseous hydrofluoric acid from corroding the circuit layer 12, thereby ensuring the integrity of the circuit layer 12.

[0071] The first bonding ring 23 , the pin structure 24 , and the pressure point 25 on the sensing layer 22 can be formed on the sensing layer 22 by deposition or etching.

[0072] Furthermore, in step S300, as shown in Figures 10-12 or 19-21, the second substrate 4 can be made of a silicon nitride substrate, a silicon carbide substrate, a silicon substrate, or the like. A second bonding ring 42 can be formed on the second substrate 4, surrounding the outer periphery of the clearance groove 41. The second bonding ring 42 is formed by deposition or etching. The clearance groove 41 can be formed by etching. First, a resist layer is formed on the bottom surface of the second substrate 4. Then, a patterned mask corresponding to the shape of the clearance groove 41 is formed on the resist layer through a photolithography process. Finally, the patterned mask is etched to form the clearance groove 41. Then, as shown in Figures 13-14 or 22-23, the second bonding ring 42 and the first bonding ring 23 of the movable inertial structure 2 are bonded together at high temperature to form a closed space between the first substrate 3 and the second substrate 4. Finally, a portion of the second substrate 4 is removed to expose the pin structure 24.

[0073] The inertial sensor prepared by the above process has the advantages of being less prone to sticking, having a stable structure, and having little restriction on the minimum size of the base structure 1 and the movable inertial structure 2. It has greater room for improvement in device performance and is conducive to improving the final performance of the inertial sensor.

[0074] The above description is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the creative concept of the present invention, but these improvements all fall within the scope of protection of the present invention.

Claims

1. An inertial sensor, comprising a base structure and a movable inertial structure spaced apart on one side of the base structure, characterized in that: The base structure includes a base layer, a circuit layer attached to the base layer and close to a side of the movable inertial structure, and a blocking structure arranged on the circuit layer, wherein the blocking structure is made of insulating material, the circuit layer has a plurality of holes and grooves penetrating in the thickness direction, the blocking structure includes a plurality of bumps connected to the circuit layer and protruding from a surface of the circuit layer away from the base layer, and the holes and grooves are embedded and blocked one by one by the bumps.

2. The inertial sensor according to claim 1, characterized in that: The blocking structure further includes a plurality of protrusions, one end of each of the plurality of protrusions being connected only to a surface of the circuit layer that is away from the base layer.

3. The inertial sensor according to claim 1, characterized in that: The convex block embedded in the hole groove comprises an embedded portion located inside the hole groove and a side edge portion connected to the top side of the embedded portion and extending along the surface of the circuit layer away from the base layer.

4. The inertial sensor according to claim 3, characterized in that: In the protrusions, at least part of the protrusions have a groove on a side away from the base layer facing the hole.

5. The inertial sensor according to claim 1, characterized in that: The barrier structure is made of silicon nitride or silicon dioxide.

6. The inertial sensor according to claim 1, characterized in that: The inertial sensor further comprises a first substrate arranged on a side of the base layer away from the circuit layer and a second substrate arranged on a side of the movable inertial structure away from the base structure, and a clearance groove is provided on a side of the second substrate facing the movable inertial structure.

7. The inertial sensor according to claim 6, characterized in that: The movable inertial structure comprises an insulating layer stacked on the circuit layer, a sensing layer stacked on the insulating layer, a first bonding ring arranged on the sensing layer, and a pin structure arranged on the sensing layer; A second engaging ring surrounding the outer circumference of the clearance groove is disposed on the bottom side of the second substrate. The position of the second engaging ring corresponds to the position of the first engaging ring and they are bonded together as a whole.

8. The inertial sensor according to claim 7, characterized in that: The middle area of ​​the sensing layer is a mass block structure for sensing motion. A pressure point is provided at a position of the sensing layer corresponding to the position of the pin structure. The pressure point is separated from the mass block structure. The pin structure is electrically connected to the circuit layer through the pressure point.

9. A method for preparing an inertial sensor, characterized in that: The steps include: A base layer, a circuit layer attached to the base layer, and a blocking structure connected to the circuit layer are formed on one side of the first substrate, wherein the blocking structure is made of insulating material, the circuit layer has a hole groove penetrating in the thickness direction, the blocking structure includes a plurality of bumps connected to the circuit layer and protruding from a surface of the circuit layer away from the base layer, and the hole groove is embedded and blocked by the bumps; forming a movable inertial structure on a side of the circuit layer away from the base layer; A second substrate having a clearance groove on one side is provided, and the second substrate is bonded to a side of the circuit layer away from the base layer, wherein the clearance groove faces the movable inertial structure.

10. The method for preparing an inertial sensor according to claim 9, characterized in that: The method comprises forming a base layer on one side of the first substrate, a circuit layer attached to the base layer, and a blocking structure connected to the circuit layer, comprising: providing a first substrate; forming a base layer on one side of the first substrate; forming a conductive layer on a side of the base layer away from the first substrate, removing part of the conductive layer material to form a hole groove penetrating in the thickness direction, and obtaining the circuit layer; An insulating layer is covered on the side of the circuit layer away from the base layer, and the insulating layer is filled in the hole groove; and part of the material of the insulating layer is removed to obtain the blocking structure.

11. The method for preparing an inertial sensor according to claim 10, characterized in that: The removing part of the material of the insulating layer to obtain the blocking structure comprises: forming a barrier layer on a surface of the insulating layer; Performing patterning on the barrier layer to expose a region where the insulating layer material needs to be removed; The insulating layer material in the area to be removed is removed by etching to obtain the blocking structure.

12. The method for preparing an inertial sensor according to claim 11, characterized in that: The method of removing the insulating layer material in the area to be removed by etching includes: The etching speed is controlled, and the etching is stopped when the bottom of the etching area is flush with the surface of the circuit layer facing away from the base layer.

Images