Touch force sensor and manufacturing method therefor

Abstract

A touch force sensor, comprising: a silicon substrate (110), comprising a varistor and wire (111) formed by impurity ions injected on a first surface of the silicon substrate (110); an insulating film layer (120), located on the first surface of the silicon substrate (110), the insulating film layer (120) comprising through holes; a silicon substrate signal electrode layer (130), located on the side of the insulating film layer (120) distant from the silicon substrate (110), the silicon substrate signal electrode layer (130) passing through the through holes to be electrically connected to the varistor and wire (111); a first annular layer (140), located on the side of the insulating film layer (120) distant from the silicon substrate (110), the surface of the silicon substrate signal electrode layer (130) distant from the silicon substrate (110) and the surface of the first annular layer (140) distant from the silicon substrate (110) being located on the same plane; and a glass substrate signal electrode layer (150), located on the side of the silicon substrate signal electrode layer (130) distant from the insulating film layer (120), the glass substrate signal electrode layer (150) being electrically connected to the silicon substrate signal electrode layer (130). The present invention further provides a manufacturing method of a touch force sensor.

Description

A force sensor and a manufacturing method thereof Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a force sensor and a manufacturing method thereof. Background Art

[0002] The force sensor can minimize the size of the sensor as much as possible by directly exposing the force sensitive film for force sensing, and avoid signal anomalies caused by the 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 strictly aligned with the cavity to achieve consistency in the sensor output. Therefore, the piezoresistor and the cavity are generally placed on the same substrate to achieve high-precision alignment. In other words, for a piezoresistive force sensor with a directly exposed force-sensitive film, an insulating thick film of materials such as SiN / SiO2 / Si needs to be plated on top of the piezoresistor and etched to form a cavity. However, the cavity made with the insulating thick film itself has high stress and the stress magnitude is difficult to control, which can easily cause process problems such as warping, fragmentation, film shedding, and wafer pattern shrinkage during the process. Residual stress can also interfere with the output signal. In addition, the coating and etching costs of the insulating thick film are high, which increases the production cost of the force sensor. Summary of the Invention

[0004] The present invention provides a force sensor and a manufacturing method thereof, which can achieve high-precision alignment between a cavity and a piezoresistor, and also avoid the process risks and residual stress problems caused by using an insulating thick film to manufacture 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 comprising a varistor and a wire formed by impurity ions implanted into a first surface of the silicon substrate;

[0007] an insulating film layer, located on the first surface of the silicon substrate, the insulating film layer comprising a through hole, wherein the through hole exposes a portion of the varistor and the wire;

[0008] 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 passing through the through hole and the varistor and electrically connected to the wire;

[0009] a first annular layer, located on a side of the insulating film layer away from the silicon substrate, wherein the silicon substrate signal electrode layer is located on an outer side of the first annular layer; a surface of the silicon substrate signal electrode layer away from the silicon substrate and a surface of the first annular layer away from the silicon substrate are in the same plane;

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

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

[0012] A glass substrate is located on a side of the signal electrode layer of the glass substrate away from the insulating film layer, and the glass substrate comprises a groove; the groove, the first annular layer, and the second annular layer form a cavity of 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 that of the signal electrode layer on the glass substrate.

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

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

[0017] Optionally, a vertical projection of the first annular layer on the silicon substrate covers an edge of the varistor and the wire close to the side wall of the cavity;

[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 further includes a contact point;

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

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

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

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

[0026] The packaging substrate is located on a 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. The method for manufacturing a force sensor is used to manufacture the force sensor provided by any embodiment of the present invention.

[0028] The production method comprises:

[0029] forming a silicon substrate, wherein the silicon substrate comprises a varistor and a conductive line formed by impurity ions implanted into a first surface of the silicon substrate;

[0030] forming an insulating film layer on the first surface of the silicon substrate, wherein the insulating film layer includes a through hole, and the through hole exposes a portion of the varistor and the wire;

[0031] forming a silicon substrate signal electrode layer on a side of the insulating film layer away from the silicon substrate, wherein the silicon substrate signal electrode layer is electrically connected to the varistor and the wire through the through hole;

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

[0033] Providing a glass substrate and forming a glass substrate signal electrode layer on one side of the glass substrate;

[0034] forming a second annular layer 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 side of the second annular layer; and the thickness of the glass substrate signal electrode layer is the same as that of the second annular layer;

[0035] forming a groove on a surface of the glass substrate close to 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 a cavity of the force sensor.

[0037] This embodiment provides a force sensor in which a silicon substrate includes a piezoresistor and a conductive wire. The piezoresistor and conductive wire are electrically connected to a signal electrode layer on the silicon substrate and a signal electrode layer on the glass substrate, thereby transmitting the resistance value of the piezoresistor through the signal electrode layer on the glass substrate. A first annular layer disposed on the same layer as the silicon substrate signal electrode layer, a second annular layer disposed on the same layer as the glass substrate signal electrode layer, and a groove in the glass substrate constitute the cavity of the force sensor. This embodiment primarily disposes the cavity in the glass substrate, eliminating the need for disposing the cavity in the insulating film layer. This avoids the problems of warping, fragmentation, shedding of the insulating film layer, and high etching costs that would result from forming a cavity in the insulating film layer and requiring a thicker insulating film layer. Providing the cavity in the glass substrate facilitates alignment of the cavity with the piezoresistor. In summary, the force sensor provided by this embodiment achieves high-precision alignment of the cavity with the piezoresistor while avoiding the process risks and residual stress associated with using thick insulating films to form the cavity.

[0038] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0040] FIG1 is a schematic structural diagram of a touch force sensor provided according to an embodiment of the present invention;

[0041] 2 is a schematic structural diagram of the positional relationship among a signal electrode layer, a first annular layer, a varistor, and a wire on a silicon substrate provided by an embodiment of the present invention;

[0042] FIG3 is a schematic structural diagram of another touch force sensor provided according to an embodiment of the present invention;

[0043] 4 is a schematic structural diagram of the positional relationship among a signal electrode layer, a first annular layer, a varistor, and a wire on a silicon substrate according to another embodiment of the present invention;

[0044] FIG5 is a schematic structural diagram of another touch force sensor provided according to an embodiment of the present invention;

[0045] FIG6 is a schematic flow chart of a method for manufacturing a force sensor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0047] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0048] Figure 1 is a schematic structural diagram of a force sensor provided according to an embodiment of the present invention, and Figure 2 is a schematic structural diagram of the positional relationship between a silicon substrate signal electrode layer, a first annular layer, a piezoresistor, and a wire provided according to an embodiment of the present invention. Referring to Figures 1 and 2, the 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 wire 111 formed by impurity ions injected into the first surface of the silicon substrate 110; the insulating film layer 120 is located on the first surface of the silicon substrate 110, and the insulating film layer 120 includes a through hole, and the through hole exposes a portion of the varistor and the wire 111; the silicon substrate signal electrode layer 130 is located on the side of the insulating film layer 120 away from the silicon substrate 110, and the silicon substrate signal electrode layer 130 is electrically connected to the wire 111 through the through hole and the varistor; the 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 first annular layer 140 away from the silicon substrate 110 are connected. the surfaces of the glass substrate are in the same plane; the glass substrate signal electrode layer 150 is located on a 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 a 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 that of the second annular layer 160; the glass substrate 170 is located on a 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 into the first surface of the silicon substrate 110 may be boron ions. The glass substrate 170 in this embodiment may be a borosilicate glass substrate, whose thermal expansion coefficient matches that of the silicon substrate 110. Referring to FIG. 2 , the varistor and the conductive wire 111 in this embodiment may 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 the first surface) is subjected to external stress, the resistance value of the piezoresistor in the piezoresistor and conductive line 111 changes. Different stresses result in different piezoresistive resistance values. The conductive line in the piezoresistor and conductive line 111 transmits this resistance value to the silicon substrate signal electrode layer 130, which then transmits it to the glass substrate signal electrode layer 150 through the silicon substrate signal electrode layer 130. The glass substrate signal electrode layer 150 can be electrically connected to other devices, which can then identify the magnitude of the stress 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. These thin layers allow the thickness of the force sensor cavity 180 to be approximately the same as the depth of the groove 171 in the glass substrate 170. In this embodiment, the groove in the glass substrate 170 forms a cavity, 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, and shedding of the insulating film layer 120 that would result from forming a cavity in the insulating film layer 120, which would require a thicker insulating film layer 120. Furthermore, these problems, such as high etching costs, can be avoided.

[0052] Before connecting the silicon substrate 110 to the glass substrate 170, the silicon substrate signal electrode layer 130 can be fixed to the silicon substrate 110, while the first annular layer 140 can be fixed to the side of the insulating film layer 120 away from the silicon substrate 110. The glass substrate signal electrode layer 150 and the second annular layer 160 are then fixed to the glass substrate 170. Finally, by bonding the first annular layer 140 to the second annular layer 160 and metal bonding the glass substrate signal electrode layer 150 to the silicon substrate signal electrode layer 130, the glass substrate 170 and the silicon substrate 110 are fixed to form a force sensor. Because the glass substrate 170 is light-transmitting, 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 efficiency of force sensor manufacturing. Furthermore, the light-transmitting nature of the glass substrate 170 facilitates identification of the positional relationship between the groove 171 in the glass substrate 170 and the piezoresistor. In summary, the force sensor provided in this embodiment defines a cavity by the groove 171 in the glass substrate 170. The high transparency of the glass substrate 170 can be utilized to achieve high-precision alignment of the cavity 180 and the piezoresistor, while avoiding the process risks and residual stress problems caused by using a thicker insulating film layer 120 to form the cavity 180.

[0053] This embodiment provides a force sensor in which a silicon substrate includes a piezoresistor and a conductive wire. The piezoresistor and conductive wire are electrically connected to the glass substrate signal electrode layer via the silicon substrate signal electrode layer, thereby transmitting the resistance value of the piezoresistor through the glass substrate signal electrode layer. A first annular layer disposed on the same layer as the silicon substrate signal electrode layer, a second annular layer disposed on the same layer as the glass substrate signal electrode layer, and a groove in the glass substrate constitute the cavity of the force sensor. This embodiment primarily disposes the cavity in the glass substrate, eliminating the need for disposing the cavity in the insulating film layer. This avoids the problems of warping, fragmentation, shedding of the insulating film layer, and high etching costs that would result from forming a cavity in the insulating film layer and requiring a thicker insulating film layer. Providing the cavity in the glass substrate facilitates alignment of the cavity with the piezoresistor. In summary, the force sensor provided by this embodiment achieves high-precision alignment of the cavity with the piezoresistor while avoiding the process risks and residual stress associated with using thick insulating films to form the cavity.

[0054] Optionally, the material of the first annular layer is the same as that of the silicon substrate signal electrode layer; the material of the second annular layer is the same as that of the glass substrate signal electrode layer. This arrangement can simultaneously form the first annular layer and the silicon substrate signal electrode layer, and can also simultaneously form the second annular layer and the glass substrate signal electrode layer, thereby improving the manufacturing efficiency of the force sensor.

[0055] Specifically, if the material of the first annular layer is the same as that 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 are simultaneously formed through an etching process. The first annular layer and the silicon substrate signal electrode layer can also be formed through a lift-off process.

[0056] If the second annular layer is made of the same material as the glass substrate's signal electrode layer, a second metal film layer can be formed on one side of the glass substrate. Then, an etching process can be used to simultaneously form the second annular layer and the glass substrate's signal electrode layer. The second annular layer and the glass substrate's signal electrode layer can also be formed using a lift-off process. The first and second annular layers define the cavity's shape, isolate it from the outside world, and provide a reference pressure.

[0057] Optionally, with continued reference to FIG1 , 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 arrangement, the first annular layer 140 and the second annular layer 160 can be manufactured using the same mask, and the cavity 180 formed can be free of protrusions, thereby improving the sensitivity of the force sensor in detecting stress.

[0058] Optionally, Figure 3 is a structural schematic diagram of another touch force sensor provided according to an embodiment of the present invention, and Figure 4 is a structural schematic diagram of the positional relationship between another silicon substrate signal electrode layer, the first annular layer, and the piezoresistor and the wire provided according to an embodiment of the present invention. Referring to Figures 3 and 4, the vertical projection of the first annular layer 140 on the silicon substrate 110 covers the edge of the piezoresistor and the wire 111 close to the side wall 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 is a partial cross-sectional view of Figure 3. The inner ring of the first annular layer 140 can extend toward the inner wall of the cavity 180, covering the edges of the piezoresistor and the wire 111 near the sidewall of the cavity 180, and electrically connected to the ground electrode 131 to achieve signal shielding, thereby enabling the force sensor provided by this embodiment to be used in strong interference environments.

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

[0061] Specifically, setting the cavity thickness within the range of 1 μm to 5 μm allows the change in cavity thickness to be slightly greater than the strain of the cavity at the maximum range of the force sensor provided by this embodiment. This prevents the force sensor from being unable to detect stress corresponding to the maximum range due to a smaller cavity thickness. Thus, setting the cavity thickness within the range of 1 μm to 5 μm can improve the force sensor's accuracy in stress detection.

[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 ranges from 100 μm to 300 μm. 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] Optionally, Figure 5 is a structural schematic diagram of another touch force sensor provided according to an embodiment of the present invention. Referring to Figure 5, the touch 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 configuration of contacts 190 can concentrate stress on contacts 190, thereby improving the sensitivity of the force sensor. Contacts 190 can be formed using a variety of manufacturing processes. For example, contacts 190 can be formed by photolithography and baking using organic materials such as PI and SU8. Contacts 190 can also be formed using photolithography using organic materials such as PI and SU8, followed by deep silicon etching and baking and reflow, thereby forming contacts 190 with a relatively high height and a curved top. Contacts 190 can also be formed using a PDMS imprinting process. Contacts 190 can also be transfer-molded after force sensor packaging is completed.

[0066] Alternatively, with continued reference to FIG. 1 or FIG. 3 , the vertical projection of the glass substrate signal electrode layer 150 on the silicon substrate 110 may coincide with the vertical projection of the silicon substrate signal electrode layer 130 on the silicon substrate 110. This arrangement, in other words, allows the glass substrate signal electrode layer 150 and the silicon substrate signal electrode layer 130 to be in a mirror-image relationship. This arrangement ensures corresponding electrical connection between the glass substrate signal electrode layer 150 and the silicon substrate signal electrode layer 130, preventing short circuits caused by stacked electrical connection between the glass substrate signal electrode layer 150 and 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 the glass substrate signal electrode layer 150 and the silicon substrate signal electrode layer 130.

[0067] Optionally, with continued reference to FIG. 5 , the force sensor provided in this embodiment further includes a packaging substrate 191 ; the packaging substrate 191 is located on a side of the glass substrate 170 away from the silicon substrate 110 .

[0068] Specifically, the package substrate 191 includes a circuit structure, and the circuit structure of the package substrate 191 is electrically connected to the glass substrate signal electrode layer 150 via a lead 192. The package substrate 191 can protect the glass substrate 170 from being easily broken by collisions with external devices.

[0069] FIG6 is a flow chart of a method for manufacturing a force sensor according to an embodiment of the present invention. The method provided in this embodiment is used to manufacture the force sensor provided in any embodiment of the present invention. Referring to FIG6 , the method for manufacturing the force sensor includes the following steps:

[0070] S110 , forming a silicon substrate, wherein the silicon substrate includes a varistor and a conductive line formed by impurity ions implanted into a first surface of the silicon substrate.

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

[0072] S120 , forming an insulating film layer on the first surface of the silicon substrate, wherein the insulating film layer includes a through hole, and the through hole exposes a portion of the varistor and the conductive line.

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

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

[0075] S140. Form a first annular layer on a 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; and a surface of the silicon substrate signal electrode layer away from the silicon substrate and a surface of the first annular layer away from the silicon substrate are in the same plane.

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

[0077] S150 , providing a glass substrate and forming a glass substrate signal electrode layer on one side of the glass substrate.

[0078] S160. Form a second annular layer 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; 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 step S150 and step S160 can be performed simultaneously, that is, the glass substrate signal electrode layer and the second annular layer are formed simultaneously on the same side of the glass substrate.

[0080] S170 , forming a groove on the surface of the glass substrate close to the signal electrode layer of the glass substrate.

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

[0082] The signal electrode layer, the second annular layer and the groove of the glass substrate can be self-aligned and formed by photolithography in one step, so as to improve the clarity of the alignment pattern during bonding alignment.

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

[0084] It should be noted that the thickness of the silicon substrate in steps S110 to S180 may be relatively thick, and the silicon substrate may be thinned to a target thickness after step S180 . The target thickness of the silicon substrate may be in the range of 100 μm to 300 μm.

[0085] The manufacturing method of the force sensor provided in this embodiment has corresponding beneficial effects as the force sensor provided in any embodiment of the present invention. For technical details not detailed 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 the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0087] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

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

2. The force sensor according to claim 1, wherein: 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 that of the signal electrode layer of the glass substrate.

3. The force sensor according to claim 1, wherein: 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; An inner ring curve of a vertical projection of the second annular layer on the silicon substrate coincides with a boundary of a vertical projection of the groove on the silicon substrate.

4. The touch force sensor according to claim 2, wherein: The vertical projection of the first annular layer on the silicon substrate covers the edge of the varistor and the wire close to the side wall of the cavity; 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, wherein: The thickness of the cavity ranges from 1 μm to 5 μm.

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

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

8. The force sensor according to claim 1, wherein: A vertical projection of the glass substrate signal electrode layer on the silicon substrate coincides with a vertical projection of the silicon substrate signal electrode layer on the silicon substrate.

9. The touch force sensor according to any one of claims 1 to 8, characterized in that: Also included is a packaging substrate; The packaging substrate is located on a 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 touch force sensor according to any one of claims 1 to 9; The production method comprises: forming a silicon substrate, wherein the silicon substrate comprises a varistor and a wire formed by impurity ions implanted on a first surface of the silicon substrate; forming an insulating film layer on the first surface of the silicon substrate, wherein the insulating film layer comprises a through hole, and the through hole exposes a portion of the varistor and the wire; Forming a silicon substrate signal electrode layer on a side of the insulating film layer away from the silicon substrate, wherein the silicon substrate signal electrode layer passes through the through hole and is electrically connected to the varistor and the wire; A first annular layer is formed on a 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; a surface of the silicon substrate signal electrode layer away from the silicon substrate and a surface of the first annular layer away from the silicon substrate are in the same plane; Providing a glass substrate and forming a glass substrate signal electrode layer 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; and the thickness of the glass substrate signal electrode layer is the same as that of the second annular layer; forming a groove on a surface of the glass substrate close to 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 a cavity of the touch force sensor.

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