A touch force sensor and a manufacturing method thereof

Abstract

The application discloses a touch force sensor and a manufacturing method thereof. The touch force sensor comprises a silicon substrate, a pressure-sensitive resistor and a wire formed by injecting impurity ions into a first surface of the silicon substrate, an insulating film layer located on the first surface of the silicon substrate, the insulating film layer comprising a through hole, a silicon substrate signal electrode layer located on a side of the insulating film layer away from the silicon substrate, the silicon substrate signal electrode layer being electrically connected with the pressure-sensitive resistor and the wire through the through hole, a first annular layer located on a side of the insulating film layer away from the silicon substrate, a surface of the silicon substrate signal electrode layer away from the silicon substrate being in the same plane as a surface of the first annular layer away from the silicon substrate, a glass substrate signal electrode layer located on a side of the silicon substrate signal electrode layer away from the insulating film layer, and the glass substrate signal electrode layer being electrically connected with the silicon substrate signal electrode layer. The application can realize high-precision alignment of the cavity and the pressure-sensitive resistor, and avoid the problems of process risk and stress residue caused by using an insulating thick film to manufacture the cavity.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a force sensor and its manufacturing method. Background Technology

[0002] Force sensors can minimize sensor size by directly exposing the force-sensitive membrane and avoid signal anomalies caused by packaging structure.

[0003] The stress distribution of a piezoresistive force sensor is strongly correlated with the position of its cavity. The piezoresistor needs to be precisely aligned with the cavity to achieve consistent sensor output. Therefore, the piezoresistor and the cavity are generally placed on the same substrate to achieve high-precision alignment. For piezoresistive force sensors with a directly exposed force-sensitive film, an insulating thick film of materials such as SiN / SiO2 / Si needs to be deposited on top of the piezoresistor and etched to form the cavity. However, the cavity made using an insulating thick film itself has high stress, and the stress magnitude is difficult to control, easily causing process problems such as warping, fragmentation, film delamination, and wafer pattern shrinkage. Residual stress can also interfere with the output signal. Furthermore, the high cost of depositing and etching the insulating thick film increases the manufacturing cost of the force sensor. Summary of the Invention

[0004] This invention provides a force sensor and its manufacturing method, which can achieve high-precision alignment between the cavity and the piezoresistor, and also avoids the process risks and stress residue problems caused by using insulating thick film to make the cavity.

[0005] According to one aspect of the present invention, a force sensor is provided, the force sensor comprising:

[0006] A silicon substrate, the silicon substrate including a varistor and a wire formed by impurity ions implanted on a first surface of the silicon substrate;

[0007] An insulating film layer is located on a first surface of the silicon substrate, the insulating film layer including through holes, the through holes exposing portions of the varistor and the wires;

[0008] A silicon substrate signal electrode layer is located on the side of the insulating film layer away from the silicon substrate, and the silicon substrate signal electrode layer is electrically connected to the wire through the through hole and the varistor;

[0009] A first annular layer is located on the side of the insulating film layer away from the silicon substrate, wherein the silicon substrate signal electrode layer is located on the outer ring side of the first annular layer; the surface of the silicon substrate signal electrode layer away from the silicon substrate is in the same plane as the surface of the first annular layer away from the silicon substrate.

[0010] A glass substrate signal electrode layer is located on the side of the silicon substrate signal electrode layer away from the insulating film layer, and the glass substrate signal electrode layer is electrically connected to the silicon substrate signal electrode layer;

[0011] The second annular layer is located on the side of the first annular layer away from the insulating film layer, wherein the glass substrate signal electrode layer is located on the outer ring side of the second annular layer; the thickness of the glass substrate signal electrode layer is the same as the thickness of the second annular layer;

[0012] A glass substrate is located on the side of the signal electrode layer of the glass substrate away from the insulating film layer. The glass substrate includes a groove. The groove, the first annular layer, and the second annular layer form a cavity for the force sensor.

[0013] Optionally, the material of the first annular layer is the same as the material of the silicon substrate signal electrode layer;

[0014] The material of the second annular layer is the same as the material of the signal electrode layer on the glass substrate.

[0015] Optionally, the vertical projection of the first annular layer on the silicon substrate coincides with the vertical projection of the second annular layer on the silicon substrate;

[0016] The inner ring curve of the vertical projection of the second annular layer onto the silicon substrate coincides with the boundary of the vertical projection of the groove onto the silicon substrate.

[0017] Optionally, the vertical projection of the first annular layer on the silicon substrate covers the edge of the varistor and the wire near the cavity sidewall;

[0018] The silicon substrate signal electrode layer includes a ground electrode, and the first annular layer is electrically connected to the ground electrode.

[0019] Optionally, the thickness of the cavity ranges from 1 μm to 5 μm.

[0020] Optionally, the thickness of the silicon substrate ranges from 100 μm to 300 μm.

[0021] Optionally, the force sensor provided in this embodiment also includes a contact point;

[0022] The contact point is located on the side of the silicon substrate away from the insulating film layer;

[0023] The vertical projection of the contact point on the insulating film layer overlaps with the vertical projection of the cavity on the insulating film layer.

[0024] Optionally, the vertical projection of the glass substrate signal electrode layer on the silicon substrate coincides with the vertical projection of the silicon substrate signal electrode layer on the silicon substrate.

[0025] Optionally, the force sensor provided in this embodiment also includes a packaging substrate;

[0026] The packaging substrate is located on the side of the glass substrate away from the silicon substrate.

[0027] According to another aspect of the present invention, a method for manufacturing a force sensor is provided, which is used to manufacture the force sensor provided in any embodiment of the present invention;

[0028] The manufacturing method includes:

[0029] A silicon substrate is formed, wherein the silicon substrate includes a varistor and a wire formed by impurity ions implanted on a first surface of the silicon substrate;

[0030] An insulating film layer is formed on a first surface of the silicon substrate, wherein the insulating film layer includes through holes, and the through holes expose portions of the varistor and the wires;

[0031] A silicon substrate signal electrode layer is formed on the side of the insulating film layer away from the silicon substrate, wherein the silicon substrate signal electrode layer passes through the via and is electrically connected to the varistor and the wire;

[0032] A first annular layer is formed on the side of the insulating film layer away from the silicon substrate, wherein the silicon substrate signal electrode layer is located on the outer ring side of the first annular layer; the surface of the silicon substrate signal electrode layer away from the silicon substrate is in the same plane as the surface of the first annular layer away from the silicon substrate.

[0033] A glass substrate is provided, and a glass substrate signal electrode layer is formed on one side of the glass substrate;

[0034] A second annular layer is formed on one side of the glass substrate, wherein the glass substrate signal electrode layer and the second annular layer are located on the same side of the glass substrate; the glass substrate signal electrode layer is located on the outer ring side of the second annular layer; the thickness of the glass substrate signal electrode layer is the same as the thickness of the second annular layer.

[0035] A groove is formed on the surface of the glass substrate near the signal electrode layer of the glass substrate;

[0036] The glass substrate signal electrode layer is bonded to the silicon substrate signal electrode layer, and the first annular layer is bonded to the second annular layer, wherein the groove, the first annular layer and the second annular layer form the cavity of the force sensor.

[0037] This embodiment provides a force sensor. The silicon substrate of the force sensor includes a varistor and wires. The varistor and wires are electrically connected to the signal electrode layer of a glass substrate through a signal electrode layer on the silicon substrate, thereby transmitting the resistance value of the varistor through the signal electrode layer of the glass substrate. A first annular layer disposed on the same layer as the signal electrode layer of the silicon substrate, a second annular layer disposed on the same layer as the signal electrode layer of the glass substrate, and a groove in the glass substrate constitute the cavity of the force sensor. This embodiment mainly sets the cavity in the glass substrate, eliminating the need to set the cavity in the insulating film layer. This avoids the problems of warping, fragmentation, insulating film peeling, and high etching costs caused by forming a cavity in the insulating film layer, which requires a thicker insulating film layer. Setting the cavity in the glass substrate facilitates the alignment of the cavity and the varistor. In summary, the force sensor provided by this embodiment can achieve high-precision alignment between the cavity and the varistor, and also avoids the process risks and stress residue problems caused by using a thick insulating film to make the cavity.

[0038] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the structure of a force sensor according to an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the positional relationship between a silicon substrate signal electrode layer, a first annular layer, a varistor, and a wire, according to an embodiment of the present invention.

[0042] Figure 3 This is a schematic diagram of the structure of another force sensor provided according to an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of the positional relationship between a silicon substrate signal electrode layer, a first annular layer, a varistor, and a wire, according to an embodiment of the present invention.

[0044] Figure 5 This is a schematic diagram of the structure of another force sensor provided according to an embodiment of the present invention;

[0045] Figure 6This is a schematic flowchart of a method for manufacturing a force sensor according to an embodiment of the present invention. Detailed Implementation

[0046] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0047] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0048] Figure 1 This is a schematic diagram of a force sensor according to an embodiment of the present invention. Figure 2 This is a schematic diagram illustrating the positional relationship between a silicon substrate signal electrode layer, a first annular layer, a varistor, and a wire, according to an embodiment of the present invention. (Refer to...) Figure 1 and Figure 2The force sensor provided in this embodiment includes: a silicon substrate 110 (also known as a force-sensitive film), an insulating film layer 120, a silicon substrate signal electrode layer 130, a first annular layer 140, a glass substrate signal electrode layer 150, a second annular layer 160, and a glass substrate 170. The silicon substrate 110 includes a varistor and a conductive line 111 formed by impurity ions implanted on a first surface of the silicon substrate 110; an insulating film layer 120 is located on the first surface of the silicon substrate 110, the insulating film layer 120 includes through-holes, the through-holes exposing the varistor and the conductive line 111; a silicon substrate signal electrode layer 130 is located on the side of the insulating film layer 120 away from the silicon substrate 110, the silicon substrate signal electrode layer 130 is electrically connected to the conductive line 111 through the through-holes and the varistor; a first annular layer 140 is located on the side of the insulating film layer 120 away from the silicon substrate 110, wherein the silicon substrate signal electrode layer 130 is located on the outer ring side of the first annular layer 140; the surface of the silicon substrate signal electrode layer 130 away from the silicon substrate 110 and the surface of the first annular layer 140 away from the silicon substrate 110 are respectively connected. The surfaces are on the same plane; the glass substrate signal electrode layer 150 is located on the side of the silicon substrate signal electrode layer 130 away from the insulating film layer 120, and the glass substrate signal electrode layer 150 is electrically connected to the silicon substrate signal electrode layer 130; the second annular layer 160 is located on the side of the first annular layer 140 away from the insulating film layer 120, wherein the glass substrate signal electrode layer 150 is located on the outer ring side of the second annular layer 160; the thickness of the glass substrate signal electrode layer 150 is the same as the thickness of the second annular layer 160; the glass substrate 170 is located on the side of the glass substrate signal electrode layer 150 away from the insulating film layer 120, and the glass substrate 170 includes a groove 171; the groove 171, the first annular layer 140 and the second annular layer 160 form a cavity 180 of the force sensor.

[0049] Specifically, the impurity ions implanted on the first surface of the silicon substrate 110 can be boron ions. In this embodiment, the glass substrate 170 can be a borosilicate glass substrate, and the coefficient of thermal expansion of the borosilicate glass substrate matches that of the silicon substrate 110. (Reference) Figure 2 In this embodiment, the varistor and the wire 111 can form a Wheatstone bridge structure.

[0050] Both the silicon substrate signal electrode layer 130 and the glass substrate signal electrode layer 150 are conductive. When the second surface of the silicon substrate 110 (the second surface is disposed opposite to the first surface) is subjected to external stress, the resistance value of the varistor and the varistor in the wire 111 will change. The varistor value will be different when the stress is different. The varistor and the wire in the wire 111 transmit the resistance value to the silicon substrate signal electrode layer 130, and then through the silicon substrate signal electrode layer 130 to the glass substrate signal electrode layer 150. The glass substrate signal electrode layer 150 can be electrically connected to other devices, and other devices can identify the stress magnitude based on the resistance value.

[0051] The thickness of the first annular layer 140 and the second annular layer 160 are generally between tens and hundreds of nanometers. Their thickness is relatively thin, and the thickness of the cavity 180 of the force sensor is approximately the same as the depth of the groove 171 in the glass substrate 170. In this embodiment, the cavity is formed by the groove in the glass substrate 170, eliminating the need to form a cavity in the insulating film layer 120. This reduces the thickness of the insulating film layer 120 and avoids problems such as warping, fragmentation, detachment of the insulating film layer 120, and high etching costs associated with forming a cavity in the insulating film layer 120.

[0052] Before connecting the silicon substrate 110 and the glass substrate 170, the silicon substrate signal electrode layer 130 can be fixed integrally with the silicon substrate 110, while the first annular layer 140 is fixed to the side of the insulating film layer 120 away from the silicon substrate 110. Then, the glass substrate signal electrode layer 150 and the second annular layer 160 are fixed integrally with the glass substrate 170. Finally, by bonding the first annular layer 140 and the second annular layer 160, and by metal bonding the glass substrate signal electrode layer 150 and the silicon substrate signal electrode layer 130, the glass substrate 170 and the silicon substrate 110 can be fixed integrally, thereby forming a force sensor. Because the glass substrate 170 is transparent, the glass substrate signal electrode layer 150 is easily aligned with the silicon substrate signal electrode layer 130, and the second annular layer 160 is easily aligned with the first annular layer 140, thereby improving the manufacturing efficiency of the force sensor. Furthermore, because the glass substrate 170 is transparent, the positional relationship between the groove 171 in the glass substrate 170 and the piezoresistor is also easy to identify. In summary, the force sensor provided in this embodiment defines a cavity through the groove 171 in the glass substrate 170. The high transparency of the glass substrate 170 can be used to achieve high-precision alignment between the cavity 180 and the piezoresistor. At the same time, it avoids the process risks and stress residue problems caused by using a thicker insulating film layer 120 to make the cavity 180.

[0053] This embodiment provides a force sensor. The silicon substrate of the force sensor includes a varistor and wires. The varistor and wires are electrically connected to the signal electrode layer of a glass substrate through a signal electrode layer on the silicon substrate, thereby transmitting the resistance value of the varistor through the signal electrode layer of the glass substrate. A first annular layer disposed on the same layer as the signal electrode layer of the silicon substrate, a second annular layer disposed on the same layer as the signal electrode layer of the glass substrate, and a groove in the glass substrate constitute the cavity of the force sensor. This embodiment mainly sets the cavity in the glass substrate, eliminating the need to set the cavity in the insulating film layer. This avoids the problems of warping, fragmentation, insulating film peeling, and high etching costs caused by forming a cavity in the insulating film layer, which requires a thicker insulating film layer. Setting the cavity in the glass substrate facilitates the alignment of the cavity and the varistor. In summary, the force sensor provided by this embodiment can achieve high-precision alignment between the cavity and the varistor, and also avoids the process risks and stress residue problems caused by using a thick insulating film to make the cavity.

[0054] Optionally, the material of the first annular layer is the same as the material of the silicon substrate signal electrode layer; the material of the second annular layer is the same as the material of the glass substrate signal electrode layer. This arrangement allows for the simultaneous formation of the first annular layer and the silicon substrate signal electrode layer, or the simultaneous formation of the second annular layer and the glass substrate signal electrode layer, thereby improving the manufacturing efficiency of the force sensor.

[0055] Specifically, when the material of the first annular layer is the same as the material of the silicon substrate signal electrode layer, a first metal film layer can be formed on the side of the insulating film layer away from the silicon substrate, and then the first annular layer and the silicon substrate signal electrode layer can be formed simultaneously by an etching process. The first annular layer and the silicon substrate signal electrode layer can also be formed by a lift-off process.

[0056] When the material of the second annular layer is the same as that of the glass substrate signal electrode layer, a second metal film layer can be formed on one side of the glass substrate, and then the second annular layer and the glass substrate signal electrode layer can be formed simultaneously through an etching process. Alternatively, the second annular layer and the glass substrate signal electrode layer can be formed using a lift-off process. The first and second annular layers define the shape of the cavity, isolate the cavity from the outside environment, and provide a reference pressure.

[0057] Optional, continue to refer to Figure 1 The vertical projection of the first annular layer 140 on the silicon substrate 110 coincides with the vertical projection of the second annular layer 160 on the silicon substrate 110; the inner ring curve of the vertical projection of the second annular layer 160 on the silicon substrate 110 coincides with the boundary of the vertical projection of the groove 171 on the silicon substrate 110. With this configuration, the first annular layer 140 and the second annular layer 160 can be fabricated using the same photomask, and the cavity 180 formed can be free of protrusions, thereby improving the sensitivity of the force sensor in detecting stress.

[0058] Optional, Figure 3 This is a schematic diagram of the structure of another force sensor provided according to an embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the positional relationship between the signal electrode layer, the first annular layer, the varistor, and the wires on a silicon substrate according to an embodiment of the present invention. (Refer to...) Figure 3 and Figure 4 The vertical projection of the first annular layer 140 on the silicon substrate 110 covers the edge of the varistor and the wire 111 near the sidewall of the cavity 180; the silicon substrate signal electrode layer 130 includes a ground electrode 131, and the first annular layer 140 is electrically connected to the ground electrode 131.

[0059] Specifically, Figure 4 for Figure 3 Partial cross-sectional view. The inner ring of the first annular layer 140 can extend towards the inner wall of the cavity 180, covering the edge of the piezoresistor and the wire 111 near the side wall of the cavity 180, and is electrically connected to the ground electrode 131 to achieve signal shielding function, thereby enabling the force sensor provided in this embodiment to be used in a strong interference environment.

[0060] Optionally, the thickness of the cavity can range from 1 μm to 5 μm.

[0061] Specifically, setting the cavity thickness within the range of 1μm to 5μm allows the cavity thickness variation to be slightly greater than the cavity strain at the maximum range of the force sensor provided in this embodiment. This avoids the force sensor failing to detect the stress corresponding to the maximum range due to a small cavity thickness. Therefore, setting the cavity thickness within the range of 1μm to 5μm can improve the accuracy of the force sensor in detecting stress.

[0062] It should be noted that the thickness of the cavity in this embodiment is the sum of the thickness of the first annular layer, the thickness of the second annular layer, and the depth of the groove. The thickness of the cavity in this embodiment refers to the thickness of the force sensor when it is not under stress.

[0063] Optionally, the thickness of the silicon substrate can range from 100μm to 300μm. This setting can increase the stress range that the silicon substrate can withstand, increase the maximum range of the force sensor, and thus expand the application scenarios of the force sensor.

[0064] Optional, Figure 5 This is a schematic diagram of the structure of another force sensor provided according to an embodiment of the present invention, with reference to... Figure 5 The force sensor provided in this embodiment also includes a contact 190; the contact 190 is located on the side of the silicon substrate 110 away from the insulating film layer 120; the vertical projection of the contact 190 on the insulating film layer 120 overlaps with the vertical projection of the cavity 180 on the insulating film layer 120.

[0065] Specifically, the placement of contact 190 allows stress to concentrate on it, thereby improving the sensitivity of the force sensor. Contact 190 can be formed using various manufacturing processes. For example, contact 190 can be formed by photolithography and baking using organic materials such as PI or SU8. Alternatively, contact 190 can be formed by photolithography using organic materials such as PI or SU8, followed by deep silicon etching and then baking and reflowing to create a contact 190 with a relatively large height and an arc-shaped top. Contact 190 can also be formed using PDMS imprinting. Contact 190 can also be transferred and formed after the force sensor is packaged.

[0066] Optional, continue to refer to Figure 1 or Figure 3 The vertical projection of the glass substrate signal electrode layer 150 onto the silicon substrate 110 coincides with the vertical projection of the silicon substrate signal electrode layer 130 onto the silicon substrate 110, meaning the glass substrate signal electrode layer 150 and the silicon substrate signal electrode layer 130 are mirror images of each other. This arrangement ensures that the glass substrate signal electrode layer 150 and the silicon substrate signal electrode layer 130 are electrically connected, avoiding short circuits caused by the glass substrate signal electrode layer 150 being electrically connected to other electrode layers, thereby improving the reliability of the force sensor. Furthermore, the mirror image relationship between the glass substrate signal electrode layer 150 and the silicon substrate signal electrode layer 130 also improves the bonding stability between them.

[0067] Optional, continue to refer to Figure 5 The force sensor provided in this embodiment also includes a packaging substrate 191; the packaging substrate 191 is located on the side of the glass substrate 170 away from the silicon substrate 110.

[0068] Specifically, the packaging substrate 191 includes a circuit structure, which is electrically connected to the signal electrode layer 150 of the glass substrate via leads 192. The packaging substrate 191 protects the glass substrate 170 from breakage by external devices.

[0069] Figure 6 This is a schematic flowchart illustrating a method for manufacturing a force sensor according to an embodiment of the present invention. The manufacturing method provided in this embodiment is used to manufacture the force sensor provided in any embodiment of the present invention; see reference. Figure 6 The manufacturing method of a force sensor includes the following steps:

[0070] S110, Forming a silicon substrate, wherein the silicon substrate includes a varistor and a wire formed by impurity ions implanted on a first surface of the silicon substrate.

[0071] Specifically, the varistor and wires are formed on a silicon substrate through photolithography and boron ion implantation.

[0072] S120. An insulating film layer is formed on the first surface of a silicon substrate, wherein the insulating film layer includes through holes, and the through holes expose a varistor and a wire.

[0073] Specifically, an insulating transition film layer is first formed on one side of the silicon substrate by depositing SiO2 or SiN, and then an insulating layer with through holes is formed by photolithography and etching.

[0074] S130. A silicon substrate signal electrode layer is formed on the side of the insulating film layer away from the silicon substrate, wherein the silicon substrate signal electrode layer passes through a via and is electrically connected to a varistor and a wire.

[0075] S140. A first annular layer is formed on the side of the insulating film layer away from the silicon substrate, wherein the silicon substrate signal electrode layer is located on the outer ring side of the first annular layer; the surface of the silicon substrate signal electrode layer away from the silicon substrate and the surface of the first annular layer away from the silicon substrate are on the same plane.

[0076] It should be noted that steps S130 and S140 can be formed simultaneously, that is, the silicon substrate signal electrode layer and the first annular layer are formed simultaneously.

[0077] S150, A glass substrate is provided and a glass substrate signal electrode layer is formed on one side of the glass substrate.

[0078] S160. A second annular layer is formed on one side of a glass substrate, wherein the glass substrate signal electrode layer and the second annular layer are located on the same side of the glass substrate; the glass substrate signal electrode layer is located on the outer ring side of the second annular layer; and the thickness of the glass substrate signal electrode layer is the same as the thickness of the second annular layer.

[0079] It should be noted that steps S150 and S160 can be formed simultaneously, that is, the glass substrate signal electrode layer and the second annular layer are formed on the same side of the glass substrate at the same time.

[0080] S170. A groove is formed on the surface of the glass substrate near the signal electrode layer of the glass substrate.

[0081] It should be noted that steps S150, S160 and S170 can be formed simultaneously, that is, the glass substrate signal electrode layer and the second annular layer are formed on the same side of the glass substrate at the same time, and a groove is formed on the glass substrate at the same time.

[0082] The signal electrode layer, the second annular layer, and the groove on the glass substrate can be self-aligned through a single photolithography process to improve the clarity of the alignment pattern during bonding alignment.

[0083] S180. The signal electrode layer of the glass substrate is bonded to the signal electrode layer of the silicon substrate, and the first annular layer is bonded to the second annular layer, wherein the groove, the first annular layer and the second annular layer form the cavity of the force sensor.

[0084] It should be noted that the thickness of the silicon substrate in steps S110 to S180 can be relatively thick. After step S180, the silicon substrate can be thinned to the target thickness, which can be in the range of 100μm to 300μm.

[0085] The method for manufacturing the force sensor provided in this embodiment has the same beneficial effects as the force sensor provided in any embodiment of the present invention. For technical details not covered in this embodiment, please refer to the force sensor provided in any embodiment of the present invention.

[0086] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0087] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A force sensor, characterized in that, include: A silicon substrate, the silicon substrate including a varistor and a wire formed by impurity ions implanted on a first surface of the silicon substrate; An insulating film layer is located on a first surface of the silicon substrate, the insulating film layer including through holes, the through holes exposing portions of the varistor and the wires; A silicon substrate signal electrode layer is located on the side of the insulating film layer away from the silicon substrate, and the silicon substrate signal electrode layer is electrically connected to the wire through the through hole and the varistor; A first annular layer is located on the side of the insulating film layer away from the silicon substrate, wherein the silicon substrate signal electrode layer is located on the outer ring side of the first annular layer; the surface of the silicon substrate signal electrode layer away from the silicon substrate is in the same plane as the surface of the first annular layer away from the silicon substrate. A glass substrate signal electrode layer is located on the side of the silicon substrate signal electrode layer away from the insulating film layer, and the glass substrate signal electrode layer is electrically connected to the silicon substrate signal electrode layer; The second annular layer is located on the side of the first annular layer away from the insulating film layer, wherein the glass substrate signal electrode layer is located on the outer ring side of the second annular layer; the thickness of the glass substrate signal electrode layer is the same as the thickness of the second annular layer; A glass substrate is located on the side of the signal electrode layer of the glass substrate away from the insulating film layer. The glass substrate includes a groove. The groove, the first annular layer, and the second annular layer form a cavity for the force sensor.

2. The force sensor according to claim 1, characterized in that, The material of the first annular layer is the same as the material of the silicon substrate signal electrode layer; The material of the second annular layer is the same as the material of the signal electrode layer on the glass substrate.

3. The force sensor according to claim 1, characterized in that, The vertical projection of the first annular layer on the silicon substrate coincides with the vertical projection of the second annular layer on the silicon substrate; The inner ring curve of the vertical projection of the second annular layer onto the silicon substrate coincides with the boundary of the vertical projection of the groove onto the silicon substrate.

4. The force sensor according to claim 2, characterized in that, The vertical projection of the first annular layer on the silicon substrate covers the edge of the varistor and the wire near the cavity sidewall; The silicon substrate signal electrode layer includes a ground electrode, and the first annular layer is electrically connected to the ground electrode.

5. The force sensor according to claim 1, characterized in that, The thickness of the cavity ranges from 1 μm to 5 μm.

6. The force sensor according to claim 1, characterized in that, The thickness of the silicon substrate ranges from 100 μm to 300 μm.

7. The force sensor according to claim 1, characterized in that, It also includes contacts; The contact point is located on the side of the silicon substrate away from the insulating film layer; The vertical projection of the contact point on the insulating film layer overlaps with the vertical projection of the cavity on the insulating film layer.

8. The force sensor according to claim 1, characterized in that, The vertical projection of the glass substrate signal electrode layer on the silicon substrate coincides with the vertical projection of the silicon substrate signal electrode layer on the silicon substrate.

9. The force sensor according to any one of claims 1-8, characterized in that, It also includes the packaging substrate; The packaging substrate is located on the side of the glass substrate away from the silicon substrate.

10. A method for manufacturing a force sensor, characterized in that, The manufacturing method is used to manufacture the force sensor according to any one of claims 1-9; The manufacturing method includes: A silicon substrate is formed, wherein the silicon substrate includes a varistor and a wire formed by impurity ions implanted on a first surface of the silicon substrate; An insulating film layer is formed on a first surface of the silicon substrate, wherein the insulating film layer includes through holes, and the through holes expose portions of the varistor and the wires; A silicon substrate signal electrode layer is formed on the side of the insulating film layer away from the silicon substrate, wherein the silicon substrate signal electrode layer passes through the via and is electrically connected to the varistor and the wire; A first annular layer is formed on the side of the insulating film layer away from the silicon substrate, wherein the silicon substrate signal electrode layer is located on the outer ring side of the first annular layer; the surface of the silicon substrate signal electrode layer away from the silicon substrate is in the same plane as the surface of the first annular layer away from the silicon substrate. A glass substrate is provided, and a glass substrate signal electrode layer is formed on one side of the glass substrate; A second annular layer is formed on one side of the glass substrate, wherein the glass substrate signal electrode layer and the second annular layer are located on the same side of the glass substrate; the glass substrate signal electrode layer is located on the outer ring side of the second annular layer; the thickness of the glass substrate signal electrode layer is the same as the thickness of the second annular layer. A groove is formed on the surface of the glass substrate near the signal electrode layer of the glass substrate; The glass substrate signal electrode layer is bonded to the silicon substrate signal electrode layer, and the first annular layer is bonded to the second annular layer, wherein the groove, the first annular layer and the second annular layer form the cavity of the force sensor.

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