CN117819469A - Inertial sensor, preparation method thereof and electronic equipment - Google Patents

Abstract

The present disclosure provides an inertial sensor, a method for manufacturing the same, and an electronic device, which belong to the technical field of inertial micro-electromechanical systems, wherein the inertial sensor is divided into at least one device unit, and the device unit is provided with a functional area and a bonding area surrounding the functional area; the inertial sensor comprises a dielectric substrate, a cover plate and a device layer arranged between the dielectric substrate and the cover plate; the dielectric substrate is provided with a first surface and a second surface which are oppositely arranged along the thickness direction; the cover plate is provided with a third surface and a fourth surface which are oppositely arranged along the thickness direction; the second surface and the third surface are arranged oppositely; the dielectric substrate is provided with a first groove penetrating through part of the thickness of the dielectric substrate, and a first opening of the first groove is positioned on the first surface; the cover plate is provided with a second groove penetrating through part of the thickness of the cover plate, and a second opening of the second groove is positioned on the fourth surface; the first groove and the second groove are both positioned in the bonding area.

Description

Inertial sensor, preparation method thereof and electronic equipment

Technical Field

The disclosure belongs to the technical field of inertial micro-electromechanical systems, and particularly relates to an inertial sensor, a preparation method thereof and electronic equipment.

Background

The inertial sensor is an inertial instrument, and an inertial measurement device and an inertial measurement system using the inertial instrument are composed of the inertial sensor. The inertial sensor includes, for example, an accelerometer, a gyroscope, an inertial measurement unit (Inertial Measurement Unit, IMU) composed of the accelerometer and the gyroscope, and the like. For six-axis IMUs, the main direction of development of inertial devices in microelectromechanical systems (Micro-electro-mechanical Systems, MEMS), the core is to integrate accelerometers and gyroscopes on a single wafer and perform wafer-level bonding packaging. And during bonding, the device layer is susceptible to compressive stress resulting in wafer warpage.

Disclosure of Invention

The disclosure aims to at least solve one of the technical problems in the prior art, and provides an inertial sensor, a preparation method thereof and electronic equipment.

In a first aspect, an inertial sensor is divided into at least one device unit, the device unit having a functional region and a bonding region surrounding the functional region; the inertial sensor comprises a dielectric substrate, a cover plate and a device layer arranged between the dielectric substrate and the cover plate;

the dielectric substrate is provided with a first surface and a second surface which are oppositely arranged along the thickness direction; the cover plate is provided with a third surface and a fourth surface which are oppositely arranged along the thickness direction; the second surface and the third surface are oppositely arranged;

the dielectric substrate is provided with a first groove penetrating through part of the thickness of the dielectric substrate, and a first opening of the first groove is positioned on the first surface; the cover plate is provided with a second groove penetrating through part of the thickness of the cover plate, and a second opening of the second groove is positioned on the fourth surface; the first groove and the second groove are both positioned in the bonding area.

In some embodiments, the material of the cover plate and/or the material of the dielectric substrate is borosilicate glass.

In some embodiments, the dielectric substrate includes a first chamber slot extending through a portion of its thickness, and a third opening of the first chamber slot is located at the second surface; the cover plate comprises a second cavity groove penetrating through part of the thickness of the cover plate, and a fourth opening of the second cavity groove is positioned on the third surface; the first chamber slot and the second chamber slot are both located in the functional zone.

In some embodiments, the device layer includes inertial devices; the first cavity groove and the second cavity groove are oppositely arranged to form a containing cavity; the accommodating chamber is positioned in the functional area; the inertial device is defined within the receiving chamber.

In some embodiments, the inertial sensor further comprises a getter film; the getter film is arranged in the second cavity groove and is attached to the bottom of the second cavity groove.

In some embodiments, the inertial sensor further comprises a bottom electrode; the bottom electrode is arranged in the first cavity groove, attached to the bottom of the first cavity groove and extending from one end to the bonding area.

In some embodiments, the first groove and/or the second groove is an annular groove surrounding the functional area.

In some embodiments, the cover plate has a plurality of through holes penetrating in a thickness direction thereof; the through hole is positioned in the bonding area and is closer to the functional area than the second groove.

In some embodiments, a conductive layer is disposed on the via inner wall.

In some embodiments, the ratio between the thickness of the dielectric substrate and the depth of the first recess is between 50 and 100; and/or the number of the groups of groups,

the ratio between the thickness of the cover plate and the depth of the second groove is 50-100.

In some embodiments, the contour shape of at least one of the first groove and the second groove comprises a quadrilateral, a hexagon, or an octagon.

In some embodiments, the first groove has the same depth as the width; the depth and the width of the second groove are the same.

In a second aspect, an embodiment of the present disclosure further provides a method for manufacturing an inertial sensor, including:

providing a dielectric substrate raw material and a cover plate raw material;

forming a first groove on the dielectric substrate raw material to obtain a dielectric substrate; the dielectric substrate is provided with a first surface and a second surface which are oppositely arranged along the thickness direction; the first opening of the first groove is positioned on the first surface;

forming a second groove on the cover plate raw material to obtain a cover plate; the cover plate is provided with a third surface and a fourth surface which are oppositely arranged along the thickness direction; the second opening of the second groove is positioned on the fourth surface;

forming a device layer on the second surface of the medium substrate, and forming the cover plate on one side of the device layer, which is away from the medium substrate, so as to obtain an inertial sensor; the inertial sensor includes at least one device unit; the device unit has a functional region and a bonding region surrounding the functional region; the first groove and the second groove are both positioned in the bonding area.

In some embodiments, after forming the second groove on the cover sheet stock, forming a cover sheet includes:

and forming a through hole penetrating through the cover plate raw material along the thickness direction of the cover plate raw material on the cover plate raw material for forming the second groove to obtain the cover plate.

In some embodiments, the inertial sensor includes a getter film;

after forming the second groove on the cover plate raw material, the method further comprises:

forming a getter film in the second groove on the cover plate raw material forming the second groove; the getter film is attached to the bottom of the second chamber groove.

In a third aspect, embodiments of the present disclosure further provide an electronic device, including an inertial sensor as in any of the above embodiments.

Drawings

FIG. 1 is a schematic diagram of an inertial sensor provided by an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a specific structure of a chamber tank in an inertial sensor according to an embodiment of the present disclosure;

FIG. 3a is a schematic diagram of a specific structure of an inertial sensor according to an embodiment of the present disclosure;

FIG. 3b is a schematic perspective view of an inertial sensor according to an embodiment of the present disclosure;

fig. 4a is a schematic view of a spatial structure of a cover plate according to an embodiment of the disclosure;

fig. 4b is a schematic view of a cover plate with a fourth surface as a viewing angle according to an embodiment of the disclosure;

FIG. 4c is a schematic view of a cover plate with a third surface as a viewing angle according to an embodiment of the disclosure;

fig. 5a is a schematic space structure diagram of a dielectric substrate according to an embodiment of the disclosure;

fig. 5b is a schematic diagram of a dielectric substrate with a first surface as a viewing angle according to an embodiment of the disclosure;

fig. 5c is a schematic diagram of a dielectric substrate with a second surface as a viewing angle according to an embodiment of the disclosure;

FIG. 6 is a schematic view of an exemplary first groove provided by an embodiment of the present disclosure;

fig. 7a to 7i are schematic flow diagrams of a method for manufacturing an inertial sensor according to an embodiment of the disclosure.

Wherein the reference numerals are as follows: an inertial sensor 100; a device unit 10; a functional area AA; a bonding region BB; a dielectric substrate 11; a cover plate 12; a device layer 13; a first surface 11a; a second surface 11b; a third surface 12a; a fourth surface 12b; a first groove 111; a first chamber slot 112; a second groove 121; a second chamber slot 122; a housing chamber 20; an inertial device 131; an accelerometer 131a; a gyroscope 131b; a getter film 14; a bottom electrode 15; a first sub-groove 111a; a through hole 123; a conductive layer 16; a wire bonding layer 17; a device preparation layer 30.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is apparent that the described embodiments are only some embodiments of the present disclosure, but not all embodiments. The components of the embodiments of the present disclosure, which are generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present disclosure provided in the accompanying drawings is not intended to limit the scope of the disclosure, as claimed, but is merely representative of selected embodiments of the disclosure. All other embodiments, which can be made by those skilled in the art based on the embodiments of this disclosure without making any inventive effort, are intended to be within the scope of this disclosure.

Unless defined otherwise, technical or scientific terms used in this disclosure should be given the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The terms "first," "second," and the like, as used in this disclosure, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Likewise, the terms "a," "an," or "the" and similar terms do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.

Reference in the present disclosure to "a plurality of" or "a number" means two or more than two. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a exists alone, A and B exist together, and B exists alone. The character "/" generally indicates that the context-dependent object is an "or" relationship.

In the related art, six-axis IMU is a mainstream development direction of inertial devices in MEMS, and a manufacturing core thereof is to integrate an accelerometer and a gyroscope on a single wafer and perform wafer-level bonding packaging. And during bonding, the device layer is susceptible to compressive stress resulting in wafer warpage. In the conventional technology, in order to prevent the wafer from warping, a bonding layer material adopted in the bonding process of the inertial sensor is usually noble metal gold (Au), and the use of noble metal in the bonding process greatly increases the manufacturing cost of the inertial sensor. In addition, in order to improve insulativity and reduce the influence of parasitic capacitance on device signals, in the process of preparing the inertial sensor, a PN node is usually prepared under a bottom electrode of the inertial sensor or high-resistance silicon is adopted as a dielectric substrate, so that the difficulty of the process of preparing the inertial sensor is increased, and the manufacturing cost of the inertial sensor is further increased.

Based on this, the present disclosure provides, among other things, an inertial sensor 100 that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. Fig. 1 is a schematic diagram of an inertial sensor according to an embodiment of the present disclosure, as shown in fig. 1, specifically, an inertial sensor 100 is divided into at least one device unit 10, where the device unit 10 has a functional area AA and a bonding area BB surrounding the functional area AA; the inertial sensor 100 includes a dielectric substrate 11, a cover plate 12, and a device layer 13 disposed between the dielectric substrate 11 and the cover plate 12; the dielectric substrate 11 has a first surface 11a and a second surface 11b disposed opposite to each other in a thickness direction Z thereof; the cover plate 12 has a third surface 12a and a fourth surface 12b disposed opposite to each other in the thickness direction Z thereof; the second surface 11b and the third surface 12a are disposed opposite to each other; the dielectric substrate 11 has a first groove 111 penetrating a part of its thickness, and a first opening of the first groove 111 is located on the first surface 11a; the cover plate 12 has a second groove 121 penetrating a part of the thickness thereof, and a second opening of the second groove 121 is located on the fourth surface 12b; the first recess 111 and the second recess 121 are both located in the bonding region BB.

According to the embodiment of the disclosure, the first groove 111 is formed in the bonding region BB of the dielectric substrate 11, so that when the dielectric substrate 11 is bonded with the device layer 13, the device layer 13 is prevented from warping due to the compressive stress applied to the device layer 13, and the flatness of the bonded device layer 13 is ensured. Similarly, by providing the second groove 121 in the bonding region BB on the cover plate 12, the compressive stress applied to the device layer 13 when the cover plate 12 is bonded to the device layer 13 can be released, the device layer 13 is prevented from being warped, and the flatness of the bonded device layer 13 is ensured. The embodiment of the disclosure improves the inherent structure of the inertial sensor 100, namely improves the dielectric substrate 11 and the cover plate 12 existing in the inertial sensor 100, and can release the compressive stress suffered by the device layer 13 without additionally preparing precious metal bonding, thereby reducing the manufacturing cost of the inertial sensor 100 and simplifying the manufacturing process of the inertial sensor 100.

In the following, a detailed description will be given of a specific structure of an inertial sensor 100 provided in an embodiment of the present disclosure, as shown in fig. 1, the inertial sensor 100 is divided into at least one device unit 10, and the device unit 10 has a functional area AA and a bonding area BB surrounding the functional area AA; the inertial sensor 100 includes a dielectric substrate 11, a cover plate 12, and a device layer 13 disposed between the dielectric substrate 11 and the cover plate 12.

The inertial sensor 100 in embodiments of the present disclosure may be a six-axis inertial sensor. The embodiments of the present disclosure will be described with reference to a six-axis inertial sensor. Of course, the inertial sensor in the embodiment of the present disclosure may also be a dual-axis inertial sensor, a three-axis inertial sensor, a four-axis inertial sensor, etc., and specifically may be designed according to the requirements in the application scenario, which is not specifically limited.

The device layer 13 comprises inertial devices 131 (see in particular fig. 2 or 3a described below) of the inertial sensor 100, the inertial devices 131 comprising for example accelerometers 131a, gyroscopes 131b, etc. The functional area AA of the device unit 10 is used for setting the inertial device 131. The bonding region BB of the device unit 10 is used for bonding between the film layers of the inertial sensor 100, for example, bonding between the dielectric substrate 11 and the device layer 13, and bonding between the cover plate 12 and the device layer 13.

The number of device units 10 is related to the number of inertial devices 131 in inertial sensor 100. The inertial device 131 includes, for example, an accelerometer 131a, a gyroscope 131b, and the like. The inertial sensor 100 is at least one of an accelerometer 131a, a gyroscope 131b, or a combination of both. For example, if the inertial device 131 in the inertial sensor 100 includes the accelerometer 131a and the gyroscope 131b, the inertial sensor 100 is divided into two device units 10 arranged in parallel, wherein one device unit 10 includes the accelerometer 131a and is located in the functional area AA of the device unit 10, and the other device unit 10 includes the gyroscope 131b and is located in the functional area AA of the device unit 10. As another example, if the inertial device 131 in the inertial sensor 100 includes only the accelerometer 131a (or only the gyroscope 131 b), the inertial sensor 100 is the device unit 10, and the functional area AA in the inertial sensor 100 is provided with the accelerometer 131a (or the gyroscope 131 b).

As shown in fig. 1, the dielectric substrate 11 has a first surface 11a and a second surface 11b disposed opposite to each other in a thickness direction Z thereof; the cover plate 12 has a third surface 12a and a fourth surface 12b disposed opposite to each other in the thickness direction Z thereof; the second surface 11b and the third surface 12a are disposed opposite to each other. The dielectric substrate 11 has a first groove 111 penetrating a part of its thickness, and a first opening of the first groove 111 is located on the first surface 11a; the cover plate 12 has a second groove 121 penetrating a part of the thickness thereof, and a second opening of the second groove 121 is located on the fourth surface 12b; the first recess 111 and the second recess 121 are both located in the bonding region BB.

Here, the first surface 11a and the fourth surface 12b are both outer surfaces of the inertial sensor 100, wherein the first surface 11a is a bottom surface of the inertial sensor 100, and the fourth surface 12b is a top surface of the inertial sensor 100. When the dielectric substrate 11 is bonded with the device layer 13, the first groove 111 located at the bonding region BB on the bottom surface can release the compressive stress suffered by the device layer 13, reduce the device warpage caused by the compressive stress, and reduce the risk of cracking of the device layer 13. The second groove 121 is located in the bonding region BB of the top surface, and when the cover plate 12 is bonded with the device layer 13, the second groove 121 located in the bonding region BB can release the compressive stress suffered by the device layer 13, so that the device warpage caused by the compressive stress is reduced, and the risk of cracking of the device layer 13 is reduced.

In some embodiments, the material of the cover plate 12 and/or the material of the dielectric substrate 11 is borosilicate glass. Since borosilicate glass is known to be a material with high resistance and low dielectric loss, the material of the dielectric substrate 11 in the embodiment of the disclosure has low dielectric loss and high resistivity compared with the silicon dielectric substrate 11, and can effectively reduce the influence of parasitic capacitance formed in the device structure on the signal of the inertial sensor 100. The material of the cover plate 12 is borosilicate glass, so that the device structure can be ensured to form smaller parasitic capacitance. In addition, the borosilicate glass material is used as a bonding material, so that the cost of the bonding material is reduced; compared with the preparation process of the high-resistance silicon medium substrate, the preparation process of the glass cover plate and the glass medium substrate has smaller difficulty, and the manufacturing cost of the inertial sensor 100 can be further reduced.

In some embodiments, fig. 2 is a schematic diagram of a specific structure of a cavity groove in an inertial sensor according to an embodiment of the disclosure, as shown in fig. 2, a dielectric substrate 11 includes a first cavity groove 112 penetrating a part of a thickness thereof, and a third opening of the first cavity groove 112 is located on a second surface 11b; the cover plate 12 includes a second chamber slot 122 extending through a portion of its thickness, and a fourth opening of the second chamber slot 122 is located on the third surface 12a; the first chamber slot 112 and the second chamber slot 122 are both located in the functional area AA.

The first chamber slot 112 and the second chamber slot 122 are both located in the functional area AA, and can provide a movable space for the inertial device 131 in the inertial sensor 100.

The depth of the first chamber trench 112 may be determined based on the structure to be accommodated and the space range where the inertial device 131 is movable, for example, the first chamber trench 112 is used to accommodate the bottom electrode 15 of the inertial sensor 100, the depth of the first chamber trench 112 may be determined based on the thickness of the bottom electrode 15, specifically, the depth of the first chamber trench 112 is greater than the thickness of the bottom electrode 15, and the remaining available space within the first chamber trench 112 is available for the movable space of the inertial device 131 in the device layer 13, except for the space occupied by the bottom electrode 15. Similarly, the depth of the second chamber trench 122 may be determined based on the structure to be accommodated and the space range where the inertial device 131 is movable, for example, the depth of the second chamber trench 122 may be determined based on the thickness of the getter film 14 for accommodating the getter film 14 of the inertial sensor 100, specifically, the depth of the second chamber trench 122 is greater than the thickness of the getter film 14, and the remaining available space in the first chamber trench 112 is available for the movable space of the inertial device 131 in the device layer 13, except for the space occupied by the bottom electrode 15.

Fig. 3a is a schematic structural diagram of an inertial sensor according to an embodiment of the disclosure, and fig. 3b is a schematic structural diagram of an inertial sensor according to an embodiment of the disclosure. Fig. 4a is a schematic view of a space structure of a cover plate provided by an embodiment of the present disclosure, fig. 4b is a schematic view of a cover plate provided by an embodiment of the present disclosure with a fourth surface as a viewing angle, and fig. 4c is a schematic view of a cover plate provided by an embodiment of the present disclosure with a third surface as a viewing angle. Fig. 5a is a schematic view of a spatial structure of a dielectric substrate provided by an embodiment of the present disclosure, fig. 5b is a schematic view of a dielectric substrate provided by an embodiment of the present disclosure with a first surface as a viewing angle, and fig. 5c is a schematic view of a dielectric substrate provided by an embodiment of the present disclosure with a second surface as a viewing angle.

In some embodiments, as shown in fig. 3a, device layer 13 includes inertial devices 131; the first chamber slot 112 and the second chamber slot 122 are disposed opposite to each other to form the accommodating chamber 20; the accommodation chamber 20 is located in the functional area AA; an inertial device 131 is defined within the containment chamber 20.

Optionally, the first cavity groove 112 and the second cavity groove 122 are identical in shape and size, and the first cavity groove 112 and the second cavity groove 122 are disposed opposite to each other, so that a regular accommodating space, that is, the accommodating cavity 20, is formed in the functional area AA, and the inertial device 131 in the device layer 13 can be defined in the accommodating cavity 20.

In some embodiments, the inertial sensor 100 pieces are susceptible to high temperature, high pressure during bonding, the first and second chamber slots 112, 122 break the bond, and the presence of higher air pressure in the receiving chamber 20 will also affect the inertial device 131 located within the movable receiving chamber 20. Therefore, it is necessary to secure a low pressure of the inner space of the accommodating chamber 20.

As shown in fig. 3a, 4 a-4 c, the inertial sensor 100 further includes a getter film 14; the getter film 14 is disposed in the second chamber groove 122 and is attached to the bottom of the second chamber groove 122 for securing the low pressure of the receiving chamber 20 in the inertial sensor 100.

Alternatively, the material of the getter film 14 may be titanium (Ti).

In some embodiments, as shown in fig. 3a, 5 a-5 c, inertial sensor 100 further includes bottom electrode 15; the bottom electrode 15 is disposed in the first chamber groove 112, is attached to the bottom of the first chamber groove 112, and extends from one end to the bonding region BB. One end of the bottom electrode 15 extends from within the first chamber groove 112 of the functional area AA to the second surface 11b of the dielectric substrate 11 of the bonding area BB, and a portion of the bottom electrode 15 extending to the second surface 11b of the dielectric substrate 11 is used for bonding with the device layer 13. The bonding method may be, for example, but not limited to, welding.

Illustratively, the material of the bottom electrode 15 may include, but is not limited to, titanium (Ti), copper (Cu).

In some embodiments, as shown in fig. 3b, 4a and 4b, the first groove 111 and/or the second groove 121 is an annular groove surrounding the functional area AA.

Here, for one device unit 10, the annular groove surrounds the entire functional area AA, the bonding area BB also surrounds the entire functional area AA, and the first groove 111 and the second groove 121 are located in the bonding area BB, so that when the film structures (i.e., the dielectric substrate 11, the cover plate 12 and the device layer 13) in the inertial sensor 100 are bonded, the annular groove surrounding the entire functional area AA can release the compressive stress on the device layer 13 in the bonding area BB in an omnibearing manner, so that the warping of the device layer 13 caused by the compressive stress is reduced, and the risk of cracking of the device layer 13 is reduced.

Optionally, the first groove 111 and the second groove 121 are identical in shape and size, and the opposite first groove 111 and second groove 121 can cooperate to release the compressive stress to which the device layer 13 is subjected at the bonding region BB, reducing the risk of cracking of the device layer 13.

In some embodiments, fig. 6 is a schematic diagram of an exemplary first groove provided in an embodiment of the disclosure, as shown in fig. 6, the first groove 111 includes a plurality of first sub-grooves 111a, each of the first sub-grooves 111a is located in a bonding area BB on the dielectric substrate 11, the first sub-grooves 111a are not communicated with each other, and a contour formed by the plurality of first sub-grooves 111a surrounds a functional area AA. The second grooves 121, like the structure shown in fig. 6, include a plurality of second sub-grooves, each of which is located in the bonding area BB on the cover plate 12, and the second sub-grooves are not communicated with each other, and the functional area AA is surrounded by a contour formed by the plurality of second sub-grooves.

Here, the mechanical strength of the dielectric substrate 11 and the cover plate 12 can be ensured while releasing the stress using the first groove 111 and the second groove 121.

Of course, in the case where the first groove 111 and the second groove 121 provided are ensured to be able to release stress, the contours of the first groove 111 and the second groove 121 may also be provided in other shapes, and the embodiment of the present disclosure is not particularly limited.

Alternatively, the profile shape of the first recess 111 and/or the second recess 121 may include, but is not limited to, a quadrilateral, a hexagon, or an octagon. For example, the profile shape of the first recess 111 and/or the second recess 121 may include, but is not limited to, rounded quadrilaterals, rounded octagons. The sides of the quadrangle are longer than the sides of the receiving chamber 20.

In some embodiments, the ratio between the thickness of the dielectric substrate 11 and the depth of the first recess 111 is between 50 and 100; and/or the ratio between the thickness of the cover plate 12 and the depth of the second recess 121 is between 50 and 100.

The first grooves 111 have a depth of between 5 μm and 8 μm and the second grooves 121 have a depth of between 5 μm and 8 μm, for example. The thickness of the dielectric substrate 11 is 400 μm to 500 μm.

In some embodiments, the depth and width of the first groove 111 are the same; the depth and width of the second groove 121 are the same.

In some embodiments, the material of device layer 13 is low-resistance monocrystalline silicon, and device layer 13 includes inertial device 131, beams for connecting inertial device 131 with other structures, parallel plates for conducting electrical signals of inertial device 131, and the like.

The thickness of the device layer 13 is, for example, between 20 μm and 60 μm.

In some embodiments, as shown in fig. 3a, 4a to 4c, the cover plate 12 has a plurality of through holes 123 penetrating in its thickness direction Z; the through hole 123 is located in the bonding region BB and is closer to the functional region AA than the second groove 121.

Here, the through holes 123 are located in the bonding region BB, and the electric potentials of the electric signal outlets of different through holes 123 corresponding to different electric signal outlets in the device layer 13 may be different or the same.

In some embodiments, the conductive layer 16 is disposed on the inner wall of the via 123. The conductive layer 16 in one through hole 123 is electrically connected to the outgoing terminal of its corresponding electrical signal, for outgoing the electrical signal of the inertial device 131.

In some embodiments, the ratio between the thickness of the cover plate 12 and the aperture of the through hole 123 is between 5 and 7.

In some embodiments, a wire bonding layer 17 is disposed on the fourth surface 12b of the cover plate 12 in electrical connection with the conductive layer 16. The wire bond layer 17 is used for wire bond connection with an external chip for conducting electrical signals of the inertial sensor 100 to the external chip, for example to an application specific integrated circuit (Application Specific Integrated Circuit, ASIC).

The above is a detailed description of the structure of the inertial sensor 100, and in the inertial sensor 100 provided in this embodiment of the disclosure, the first groove 111 is disposed in the bonding region BB of the dielectric substrate 11, and the second groove 121 is disposed in the bonding region BB of the cover 12, so that when the device layer 13 is bonded, the compressive stress applied to the device layer 13 can be released, the device layer 13 is prevented from warping, and the flatness of the bonded device layer 13 is ensured. In addition, using borosilicate glass as a bonding material can reduce the bonding cost and bonding difficulty of the inertial sensor 100.

Based on the above provided inertial sensor 100, the embodiment of the disclosure further provides a method for manufacturing the inertial sensor 100, and fig. 7a to 7i are schematic flow diagrams of the method for manufacturing the inertial sensor according to the embodiment of the disclosure, including the following steps S11 to S14:

s11, providing a dielectric substrate raw material and a cover plate raw material.

The dielectric substrate 11 is formed by structurally designing a dielectric substrate material, which is the same as the dielectric substrate 11. The material of the cover plate raw material is the same as that of the cover plate 12, and the cover plate 12 is formed by structural design of the cover plate raw material.

S12, forming a first groove 111 on the dielectric substrate raw material to obtain a dielectric substrate 11; the dielectric substrate 11 has a first surface 11a and a second surface 11b disposed opposite to each other in a thickness direction Z thereof; the first opening of the first recess 111 is located at the first surface 11a.

As shown in fig. 7a, in the implementation, the first groove area to be etched and the first cavity groove area of the dielectric substrate material can be modified by using laser induced etching; then, a wet etching process is used to etch the surface of the dielectric substrate material in the first groove region to form a first groove 111, and etch the surface of the dielectric substrate material in the first cavity groove region to form a first cavity groove 112. Here, the cross-sectional shape of the first recess 111 formed by wet etching is an inverted cone.

The first surface 11a comprises a first recess area and the second surface 11b comprises a first chamber area.

In some embodiments, inertial sensor 100 further includes bottom electrode 15. As shown in fig. 7b, after the dielectric substrate material of the first groove 111 and the first cavity groove 112 is formed, a first sub-electrode attached to the bottom of the first groove 111 is formed in the first groove 111 of the dielectric substrate material, and a second sub-electrode extending from the bottom of the first groove 111 to the second surface 11b is formed, and the first sub-electrode and the second sub-electrode are integrally formed to constitute the bottom electrode 15. For example, a metallic titanium layer or a metallic copper layer may be sputtered in the first recess 111 and at the edge of the second surface 11b adjacent to the first recess 111, and patterned to form the bottom electrode 15.

S13, forming a second groove 121 on the cover plate raw material to obtain a cover plate 12; the cover plate 12 has a third surface 12a and a fourth surface 12b disposed opposite to each other in the thickness direction Z thereof; the second opening of the second recess 121 is located in the fourth surface 12b.

As shown in fig. 7c, in the implementation, the second groove area to be etched and the second cavity groove area of the cover plate raw material can be modified by using laser induced etching; then, a wet etching process is used to etch the surface of the cover plate material in the second groove region to form a second groove 121, and etch the surface of the cover plate material in the second cavity groove region to form a second cavity groove 122. Here, the second groove 121 formed by wet etching has an inverted tapered cross-sectional shape.

The fourth surface 12b includes a second recessed area and the third surface 12a includes a second chamber area.

In some embodiments, as shown in fig. 7d, on the cover plate raw material forming the second groove 121, a through hole 123 penetrating the cover plate raw material is formed along the thickness direction Z of the cover plate raw material, resulting in the cover plate 12.

Here, the cover plate stock may be subjected to the through-hole 123 fabrication using various methods. For example: sand blasting, photosensitive glass, focused discharge, plasma etching, laser ablation, electrochemical, laser induced etching, etc. Different methods have different advantages and disadvantages and application ranges. For example, for the sand blasting method, the advantage is that the process is simple, and the aperture of the through hole 123 manufactured in this way is large, and the method is only suitable for manufacturing the through hole 123 with the aperture larger than 200 μm. The photosensitive glass method has the advantage of simple process and can manufacture through holes 123 with high density and high depth-to-width ratio. The focusing discharge method has the advantage of high pore-forming speed. The sidewall roughness of the via 123 is small by the plasma etching method. The laser ablation method has the advantage that high density, high aspect ratio vias 123 can be fabricated with large roughness. The electrochemical method has the advantages of low cost, simple equipment, high pore forming rate and larger diameter of the through hole 123. The laser-induced etching method has the advantages of high pore forming rate, capability of manufacturing the through holes 123 with high density and high depth-to-width ratio, no damage to the inside of the through holes 123 and expensive laser equipment. Here, the via 123 is prepared by using a laser induced etching method, taking laser induced etching as an example. The laser is used for performing laser-induced modification on the position where the through hole 123 needs to be formed, and then a wet etching method is used for manufacturing the through hole 123. Since the through hole 123 can be formed only by single-sided etching, the cap plate 12 is obtained. The ratio between the aperture of the through hole 123 and the thickness of the cover plate 12 is between 1:5 and 1:7. The through holes 123 should be kept as vertical as possible to the horizontal plane, reducing the space occupied by the leads.

In some embodiments, inertial sensor 100 further includes a getter film 14. As shown in fig. 7e, a conductive layer 16 is formed on the inner wall of the through hole 123; a getter film 14 attached to the bottom of the second groove 121 is formed in the second groove 121. Illustratively, the inner walls of the through holes 123 of the cover plate 12 are sputtered and plated with a metallic titanium layer or a metallic copper layer, and the inner walls of the through holes 123 are metallized to form the conductive layer 16. The getter is sputtered to the bottom of the second recess 121 to form the getter film 14.

S14, forming a device layer 13 on the second surface 11b of the dielectric substrate 11, and forming a cover plate 12 on one side of the device layer 13 away from the dielectric substrate 11 to obtain the inertial sensor 100.

Wherein the inertial sensor 100 comprises at least one device unit 10; the device unit 10 has a functional area AA and a bonding area BB surrounding the functional area AA; both the first recess 111 and the second recess 121 are located in the bonding area BB.

Specifically, as shown in fig. 7f, a low-resistance silicon layer is bonded on the second surface 11b of the dielectric substrate 11, and is ground and polished to a thickness of 20 μm to 60 μm to form a device preparation layer 30; thereafter, as shown in fig. 7g, the device preparation layer 30 may be etched by using a deep reactive ion etching process, so as to form the inertial device 131 and different potential areas, thereby obtaining the device layer 13. Different potential areas correspond to different vias 123.

Alternatively, the material of the dielectric substrate 11 may be borosilicate glass.

Here, the first groove 111 located in the bonding region BB on the dielectric substrate 11 can release the compressive stress applied to the low-resistance silicon layer of the dielectric substrate 11 when the low-resistance silicon layer is bonded, prevent the low-resistance silicon layer from warping, and ensure the flatness of the bonded device layer 13. In addition, compared with the silicon dielectric substrate 11, the material of the dielectric substrate 11 is borosilicate glass, and has the characteristics of low dielectric loss and high resistivity, so that the influence of parasitic capacitance formed in a device structure on the signal of the inertial sensor 100 can be effectively reduced. The borosilicate glass material is used as the bonding material, so that the cost of the bonding material is reduced; the difficulty of the preparation process of the glass dielectric substrate 11 is smaller than that of the preparation process of the high-resistance silicon dielectric substrate 11, and the manufacturing cost of the inertial sensor 100 can be further reduced.

As shown in fig. 7h, the bonding cover plate 12 is bonded to the device layer 13, specifically, the third surface 12a of the cover plate 12 is bonded to the surface of the device layer 13 facing away from the dielectric substrate 11; as shown in fig. 7i, a metallic titanium layer or a metallic copper layer is sputtered on the metal interconnection region of the fourth surface 12b of the cap plate 12 to form a wire bonding layer 17, thereby obtaining the inertial sensor 100.

Alternatively, the material of the cover plate 12 may be borosilicate glass.

Here, the second groove 121 on the cover plate 12 located in the bonding region BB can release the compressive stress applied to the device layer 13 when the cover plate 12 is bonded to the device layer 13, prevent the device layer 13 from warping, and ensure the flatness of the bonded device layer 13. In addition, compared with the silicon dielectric substrate 11, the material of the cover plate 12 is borosilicate glass, which has the characteristics of low dielectric loss and high resistivity, and can effectively reduce the influence of parasitic capacitance formed in the device structure on the signal of the inertial sensor 100. The borosilicate glass material is used as the bonding material, so that the cost of the bonding material is reduced; the difficulty of the preparation process of the glass cover plate 12 is smaller than that of the high-resistance silicon cover plate 12, and the manufacturing cost of the inertial sensor 100 can be further reduced.

Embodiments of the present disclosure also provide an electronic device comprising an inertial sensor 100 as in any of the above embodiments.

The inertial sensor 100 provided by embodiments of the present disclosure primarily detects and measures acceleration, tilt, shock, vibration, rotation, and multiple degree of freedom (Degree of Freedom, DOF) motions for navigation, orientation, and motion carrier control.

The inertial sensor 100 may be applied to consumer electronics, and the electronic device containing the inertial sensor 100 may be, for example, a cell phone, a global positioning system (Global Positioning System, GPS) navigation, a game console, a digital camera, a music player, a wireless mouse, a hard disk protector, a smart toy, a pedometer, an anti-theft system, etc. The inertial sensor 100 may be applied to industrial and automotive products, and the electronic devices including the inertial sensor 100 may be, for example, vehicle attitude measurement, industrial automation equipment, large medical equipment, robots, instruments, engineering machinery, and the like.

It is to be understood that the above embodiments are merely exemplary embodiments employed to illustrate the principles of the present disclosure, however, the present disclosure is not limited thereto. Various modifications and improvements may be made by those skilled in the art without departing from the spirit and substance of the disclosure, and are also considered to be within the scope of the disclosure.

Claims (16)

1. An inertial sensor divided into at least one device unit having a functional area and a bonding area surrounding the functional area; the inertial sensor comprises a dielectric substrate, a cover plate and a device layer arranged between the dielectric substrate and the cover plate;

the dielectric substrate is provided with a first surface and a second surface which are oppositely arranged along the thickness direction; the cover plate is provided with a third surface and a fourth surface which are oppositely arranged along the thickness direction; the second surface and the third surface are oppositely arranged;

the dielectric substrate is provided with a first groove penetrating through part of the thickness of the dielectric substrate, and a first opening of the first groove is positioned on the first surface; the cover plate is provided with a second groove penetrating through part of the thickness of the cover plate, and a second opening of the second groove is positioned on the fourth surface; the first groove and the second groove are both positioned in the bonding area.

2. The inertial sensor of claim 1, wherein the material of the cover plate and/or the material of the dielectric substrate is a borosilicate glass material.

3. The inertial sensor of claim 1, wherein the dielectric substrate includes a first chamber slot through a portion of its thickness, and a third opening of the first chamber slot is located at the second surface; the cover plate comprises a second cavity groove penetrating through part of the thickness of the cover plate, and a fourth opening of the second cavity groove is positioned on the third surface; the first chamber slot and the second chamber slot are both located in the functional zone.

4. An inertial sensor according to claim 3, wherein the device layer comprises inertial devices; the first cavity groove and the second cavity groove are oppositely arranged to form a containing cavity; the accommodating chamber is positioned in the functional area; the inertial device is defined within the receiving chamber.

5. An inertial sensor according to claim 3, wherein the inertial sensor further comprises a getter film; the getter film is arranged in the second cavity groove and is attached to the bottom of the second cavity groove.

6. The inertial sensor of claim 3, wherein the inertial sensor further comprises a bottom electrode; the bottom electrode is arranged in the first cavity groove, attached to the bottom of the first cavity groove and extending from one end to the bonding area.

7. The inertial sensor of claim 1, wherein the first groove and/or the second groove is an annular groove surrounding the functional area.

8. The inertial sensor according to any one of claims 1 to 7, wherein the cover plate has a plurality of through holes penetrating in a thickness direction thereof; the through hole is positioned in the bonding area and is closer to the functional area than the second groove.

9. The inertial sensor of claim 8, wherein the via inner wall is provided with a conductive layer.

10. The inertial sensor of any one of claims 1-7, wherein a ratio between a thickness of the dielectric substrate and a depth of the first recess is between 50-100; and/or the number of the groups of groups,

the ratio between the thickness of the cover plate and the depth of the second groove is 50-100.

11. The inertial sensor of any of claims 1-7, wherein a contour shape of at least one of the first groove and the second groove comprises a quadrilateral, a hexagon, or an octagon.

12. The inertial sensor of any one of claims 1-7, wherein the first groove has a depth and a width that are the same; the depth and the width of the second groove are the same.

13. A method of manufacturing an inertial sensor, comprising:

providing a dielectric substrate raw material and a cover plate raw material;

forming a first groove on the dielectric substrate raw material to obtain a dielectric substrate; the dielectric substrate is provided with a first surface and a second surface which are oppositely arranged along the thickness direction; the first opening of the first groove is positioned on the first surface;

forming a second groove on the cover plate raw material to obtain a cover plate; the cover plate is provided with a third surface and a fourth surface which are oppositely arranged along the thickness direction; the second opening of the second groove is positioned on the fourth surface;

forming a device layer on the second surface of the medium substrate, and forming the cover plate on one side of the device layer, which is away from the medium substrate, so as to obtain an inertial sensor; the inertial sensor includes at least one device unit; the device unit has a functional region and a bonding region surrounding the functional region; the first groove and the second groove are both positioned in the bonding area.

14. The method of manufacturing an inertial sensor of claim 13, wherein forming a cover after forming a second groove on the cover stock includes:

and forming a through hole penetrating through the cover plate raw material along the thickness direction of the cover plate raw material on the cover plate raw material for forming the second groove to obtain the cover plate.

15. The method of manufacturing an inertial sensor of claim 13, wherein the inertial sensor comprises a getter film;

after forming the second groove on the cover plate raw material, the method further comprises:

forming a getter film in the second groove on the cover plate raw material forming the second groove; the getter film is attached to the bottom of the second chamber groove.

16. An electronic device comprising the inertial sensor of any one of claims 1-12.