Multi-axis force sensor and preparation method therefor

Abstract

Disclosed in the present invention are a multi-axis force sensor and a preparation method therefor. The multi-axis force sensor comprises a sensor main body and a base. The sensor main body comprises a substrate, wherein a first groove is formed on a first side surface of the substrate; an island structure is formed in the center of the first groove, and is connected to an inner wall of the first groove by means of a plurality of beam structures; piezoresistors are provided on surfaces of two ends of each beam structure, the plurality of piezoresistors being electrically connected to each other; a connecting body is arranged on a second side surface of the substrate and protrudes therefrom, the connecting body being configured to be connected to an external force transmission member, and the second side surface being opposite the first side surface; the vertical projection of the connecting body on the first side surface overlaps with the vertical projection of the island structure on the first side surface; a second groove is formed on a front surface of the base; the first side surface of the substrate is bonded to the front surface of the base; and an outer edge of the substrate is supported on an outer edge of the base. Direction information of a force can be measured without needing to use a plurality of sensors, thereby saving on the costs.

Description

Multi-dimensional force sensor and preparation method thereof Technical Field

[0001] The present invention relates to semiconductor technology, and in particular to a multi-dimensional force sensor and a preparation method thereof. Background Art

[0002] The pressure-sensitive force sensor is based on the single-crystal silicon piezoresistive effect. It uses four equal-value resistors to form a Wheatstone bridge, which converts external pressure changes into corresponding electrical signal outputs to achieve the measurement of external pressure.

[0003] Currently, most pressure-sensitive force sensors are unidirectional, transmitting only the magnitude of the force, but not its direction. Force is a vector and therefore has directional information. Therefore, when directional information is required, multiple sensors are often required, which is costly. Summary of the Invention

[0004] The present invention provides a multi-dimensional force sensor and a preparation method thereof, which can detect force direction information without using multiple sensors, thus saving costs.

[0005] In a first aspect, the present invention provides a multi-dimensional force sensor, comprising:

[0006] A sensor body comprising a base, wherein a first groove is provided on a first side of the base, an island structure is provided in the center of the first groove, the island structure is connected to the inner wall of the first groove via a plurality of beam structures, and piezoresistors are provided on surfaces at both ends of the beam structure, and the plurality of piezoresistors are electrically connected. A connector is provided on a second side of the base protruding from the second side, the connector being configured to connect to an external force-conducting member, the second side being opposite to the first side, and a vertical projection of the connector on the first side overlaps a vertical projection of the island structure on the first side.

[0007] The base is provided with a second groove on the front side of the base, the first side surface of the base is bonded to the front side of the base, and the outer edge of the base is supported on the outer edge of the base.

[0008] Optionally, an insulating layer and a protective layer are further provided between the sensor body and the base, and the insulating layer covers the first side surface of the substrate, the island structure and the beam structure;

[0009] A first highly doped wire is further provided at the outer edge of the first side surface of the substrate, and the first highly doped wire is provided at both ends of the varistor and connected to the varistor;

[0010] A metal wire is provided on a side of the insulating layer away from the substrate, the metal wire passes through the insulating layer and is in ohmic contact with the first highly doped wire, and the plurality of varistors are electrically connected via the metal wire;

[0011] The protection layer covers the metal wire.

[0012] Optionally, a second highly-doped conductive line is provided on an outer edge of the first side surface of the substrate, and a lateral opening is formed in the insulating layer on the sidewall of the first groove to expose a portion of the second highly-doped conductive line.

[0013] Optionally, a stress film is provided on the bottom surface and inner wall of the first groove.

[0014] Optionally, the stress film is a metal film, and the stress film extends into the lateral opening and is connected to the exposed portion of the second highly-doped conductive line.

[0015] Optionally, the connector is a hollow structure, a first end of the connector is connected to the second side surface of the substrate, and a second end of the connector is open.

[0016] Optionally, the substrate is along <100> The silicon substrate is grown in a crystal direction, and the edges of the first groove, the island structure and the beam structure are aligned with the substrate. <110> The crystal direction and the <11(-)0> crystal direction are not parallel.

[0017] In a second aspect, the present invention further provides a method for preparing a multi-dimensional force sensor, comprising:

[0018] providing a base and a pedestal;

[0019] forming a varistor on the first side of the substrate;

[0020] Removing a portion of the substrate to form a first groove, an island structure, and a beam structure, wherein the island structure is disposed at the center of the first groove, the island structure is connected to the inner wall of the first groove via a plurality of beam structures, and piezoresistors are disposed on surfaces at both ends of the beam structure, and the plurality of piezoresistors are electrically connected;

[0021] Processing the front surface of the base, removing a portion of the base, and forming a second groove on the front surface of the base;

[0022] bonding the first side surface of the substrate to the front surface of the base, with the outer edge of the substrate supported on the outer edge of the base;

[0023] A connector for connecting an external force transmission component is formed on the second side of the substrate, the second side is opposite to the first side, and a vertical projection of the connector on the first side overlaps with a vertical projection of the island structure on the first side.

[0024] Optionally, forming a varistor on the first side of the substrate includes:

[0025] The substrate is sequentially cleaned, dried, and thermally oxidized to form an ion scattering layer on the surface of the substrate;

[0026] Ions are implanted into the first side of the substrate to form a piezoresistor on the substrate below the ion scattering layer.

[0027] Optionally, after forming the varistor on the first side of the substrate, the method further includes:

[0028] Ion implantation is performed on the first side surface of the substrate to form a plurality of first highly doped wires and second highly doped wires on the substrate below the ion scattering layer, wherein the first highly doped wires are disposed at both ends of the varistor and connected to the varistor, and the second highly doped wires are located at an outer edge of the first side surface of the substrate;

[0029] removing the ion scattering layer on the surface of the substrate;

[0030] forming an insulating layer on a first side surface of the substrate, wherein the insulating layer covers the varistor, the first highly doped wire, and the second highly doped wire;

[0031] Opening the insulating layer to form a via hole in the insulating layer, exposing a portion of the first highly doped wire and a portion of the second highly doped wire;

[0032] forming a metal wire on a surface of the insulating layer away from the substrate, the metal wire extending into the via hole and making ohmic contact with the first highly doped wire and the second highly doped wire, and the plurality of varistors being electrically connected via the metal wire;

[0033] A protection layer is formed on a surface of the insulating layer away from the substrate, and the protection layer covers the metal wire.

[0034] Optionally, removing a portion of the substrate to form the first groove, the island structure, and the beam structure includes:

[0035] Etching the beam region to remove a portion of the substrate in the beam region, as well as a portion of the insulating layer and a portion of the protective layer on the substrate, to form a plurality of sub-grooves in the beam region, wherein the plurality of sub-grooves are combined to form the first groove, and the region between the plurality of sub-grooves forms the island structure and the beam structure;

[0036] removing the polymer formed on the inner wall of the sub-groove by the etching process;

[0037] removing a portion of the insulating layer and a portion of the protective layer on the inner wall of the sub-groove, forming a lateral opening on the inner wall of the sub-groove, and exposing a portion of the second highly doped wire;

[0038] A stress film is formed on the bottom surface and inner wall of the sub-groove. The stress film extends into the lateral opening and is connected to the exposed portion of the second highly doped conductive line.

[0039] The multi-dimensional force sensor provided by the present invention includes a sensor body and a base. The sensor body includes a base. A first groove is provided on the first side of the base. An island structure is provided in the center of the first groove. The island structure is connected to the inner wall of the first groove through a plurality of beam structures. The surfaces of both ends of the beam structure are provided with piezoresistors. The plurality of piezoresistors are electrically connected. A connector protruding from the second side is provided on the second side of the base. The connector is used to connect an external force conducting component. The second side is opposite to the first side. The vertical projection of the connector on the first side overlaps with the vertical projection of the island structure on the first side. The front of the base is provided with a second groove. The first side surface is bonded to the front surface of the base, and the outer edge of the base is supported on the outer edge of the base. By setting up multiple beam structures, stresses of different properties will be distributed at different positions on different beam structures. The stress is mainly concentrated at both ends of the beam structure. The piezoresistors form a Wheatstone bridge to measure the magnitude of the force in that direction. The multiple beam structures form multiple groups of Wheatstone bridges to respectively measure the magnitude of the force / torque in each direction, and the actual magnitude of the force / torque acting on the sensor in each direction can be obtained, thereby obtaining the magnitude and direction of the force / torque acting on the sensor. The direction information of the force can be detected without using multiple sensors, saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0041] FIG1 is a schematic structural diagram of a multi-dimensional force sensor provided by an embodiment of the present invention;

[0042] FIG2 is a bottom view of the sensor body in FIG1 ;

[0043] FIG3 is a side view of the sensor body in FIG1 ;

[0044] FIG4 is a cross-sectional view of the multi-dimensional force sensor in FIG1 ;

[0045] FIG5 is a bottom view of another sensor body provided by an embodiment of the present invention;

[0046] FIG6 is a bottom view of another sensor body provided by an embodiment of the present invention;

[0047] FIG7 is a top view of a connector according to an embodiment of the present invention;

[0048] FIG8 is a cross-sectional view of another multi-dimensional force sensor provided by an embodiment of the present invention;

[0049] FIG9 is a cross-sectional view of another multi-dimensional force sensor provided by an embodiment of the present invention;

[0050] FIG10 is a flow chart of a method for preparing a multi-dimensional force sensor according to an embodiment of the present invention;

[0051] 11-14 are flow charts of another method for preparing a multi-dimensional force sensor according to an embodiment of the present invention;

[0052] FIG15 is a schematic diagram of the connection between a connector and an external force transmission component;

[0053] FIG16 is a schematic diagram showing the connection between another connector and an external force transmission component. DETAILED DESCRIPTION

[0054] To make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present invention more clearly understood, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It is apparent that the described embodiments are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0055] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0056] In the present invention, unless otherwise expressly specified and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature. In addition, the terms "first" and "second" are only used to distinguish in description and have no special meaning.

[0057] FIG1 is a schematic structural diagram of a multi-dimensional force sensor provided in an embodiment of the present invention. FIG2 is a bottom view of the sensor body in FIG1 . FIG3 is a cross-sectional view of the sensor body in FIG1 , with the section line AA in FIG2 . FIG4 is a cross-sectional view of the multi-dimensional force sensor in FIG1 , with the section line BB in FIG2 . As shown in FIG1 to FIG4 , in this embodiment, the multi-dimensional force sensor includes:

[0058] The sensor body 100 includes a base 110. A first groove 111 is provided on the first side of the base 110. An island structure 112 is provided in the center of the first groove 111. The island structure 112 is connected to the inner wall of the first groove 111 via a plurality of beam structures 113. For example, the first groove 111 is divided into a plurality of sub-grooves 1111 by the plurality of beam structures 113. Piezoresistors 114 are provided on the surfaces of both ends of the beam structure 113. The function of the piezoresistors 114 is to respond to external pressure and convert the pressure into an electrical signal. The piezoresistors 114 are electrically connected via internal wiring and to an external circuit, transmitting the electrical signal to the external circuit, thereby calculating the magnitude and direction of the external pressure. A connector 120 protruding from the second side of the base 110 is provided. The connector 120 is used to connect to an external force transmission component to transmit the external pressure to the sensor body 100. The second side surface is opposite to the first side surface, and the vertical projection of the connector 120 on the first side surface overlaps with the vertical projection of the island structure 112 on the first side surface. Exemplarily, the vertical projection of the connector 120 on the first side surface coincides with the vertical projection of the island structure 112 on the first side surface.

[0059] The base 200 has a second groove 210 on its front surface. The first side surface of the substrate 100 is bonded to the front surface of the base 200. The outer edge of the substrate 100 (i.e., the portion outside the first groove 111) is supported on the outer edge of the base 200 (i.e., the portion outside the second groove 210). The second groove 210 allows the sensor body 100 to deform under external pressure, concentrating stress on the island structure 112 and the beam structure 113.

[0060] For example, when a device is subjected to forces / torques in different directions, different stresses are distributed at different locations on different beam structures. The stress is primarily concentrated at the ends of the beam structures. The piezoresistors on the two beam structures form a Wheatstone bridge, which can measure the magnitude of the force in that direction. By arranging multiple Wheatstone bridges on the device and measuring the magnitude of the force / torque in each direction, the actual magnitude of the force / torque acting on the sensor in each direction can be determined, thereby determining the magnitude and direction of the force / torque acting on the sensor.

[0061] The multi-dimensional force sensor provided by an embodiment of the present invention includes a sensor body and a base. The sensor body includes a base. A first groove is provided on the first side of the base. An island structure is provided in the center of the first groove. The island structure is connected to the inner wall of the first groove through a plurality of beam structures. The surfaces of both ends of the beam structure are provided with piezoresistors. The plurality of piezoresistors are electrically connected. A connector protruding from the second side is provided on the second side of the base. The connector is used to connect an external force conducting member. The second side is opposite to the first side. The vertical projection of the connector on the first side overlaps with the vertical projection of the island structure on the first side. The front of the base is provided with a second groove. One side is bonded to the front side of the base, and the outer edge of the base is supported on the outer edge of the base. By setting up multiple beam structures, stresses of different properties will be distributed at different positions on different beam structures. The stress is mainly concentrated at both ends of the beam structure. The piezoresistors on the two beam structures constitute a Wheatstone bridge, which can measure the magnitude of the force in that direction. Multiple beam structures form multiple groups of Wheatstone bridges, which respectively measure the magnitude of the force / torque in each direction. The actual magnitude of the force / torque acting on the sensor in each direction can be obtained, thereby obtaining the magnitude and direction of the force / torque acting on the sensor. There is no need to use multiple sensors to detect the direction information of the force, which saves costs.

[0062] For example, in the embodiment of the present invention, the material of the base 110 and the base 200 can be <100> A silicon substrate grown in a crystal direction, wherein <100> The crystal direction is a direction perpendicular to the first side surface of the substrate 110 .

[0063] The force sensor is directly affected by external stress during operation, which is relatively large. Silicon is a brittle material, so stress concentration is likely to occur during operation, causing the beam structure to break easily. <110> FIG5 is a bottom view of another sensor body provided by an embodiment of the present invention, and FIG6 is a bottom view of another sensor body provided by an embodiment of the present invention. To address the above problem, as shown in FIG5 and FIG6, the edges of the first groove (i.e., sub-groove 1111), the island structure 112, and the beam structure 113 are aligned with the substrate 110. <110> The crystal direction and the <11(-)0> crystal direction are not parallel. For example, in the embodiment of the present invention, <100> The crystal direction is a direction perpendicular to the first side surface of the substrate 110. <110> The crystal directions are the X and Y directions in Figures 5 and 6, respectively. The edges of the first groove (i.e., the sub-groove 1111), the island structure 112, and the beam structure 113 avoid the silicon substrate. <110> crystal direction and <11(-)0> crystal direction, inhibiting silicon <110> It should be noted that the embodiments shown in Figures 5 and 6 are used to illustrate the relationship between the edge lines of the island structure and the beam structure and the substrate. <110> The crystal direction and the <11(-)0> crystal direction are not parallel, and the arrangement of the varistor and the highly doped wire is similar to that in FIG2 , which is not shown in the figure.

[0064] Figure 7 is a top view of a connector according to an embodiment of the present invention. As shown in Figure 7, connector 120 can have various structural forms. For example, as shown in (a), (b), (c), and (d) in Figure 7, connector 120 can be a monolithic structure or comprised of multiple substructures, which is not limited in this embodiment of the present invention. Connector 120 is a hollow structure, with a first end of connector 120 connected to the second side surface of the substrate and a second end of connector 120 open. The hollow, concave structure of connector 120 facilitates high-precision connection and secondary packaging between connector 120 and external force-conducting components.

[0065] As shown in Figures 2 and 4-6, a first highly doped wire 115 is also provided on the first side of the substrate 110. The first highly doped wire 115 is disposed at both ends of the varistor 114 and is in contact with the varistor 114. An insulating layer 320 is also provided between the sensor body 100 and the base 200. The insulating layer 320 covers the first side of the substrate 110, the island structure 120, and the beam structure 130. The first highly doped wire 115 is connected to an external circuit via a metal wire 410 that penetrates the insulating layer 320, and is used to transmit the electrical signal generated by the varistor 114 to the external circuit. A protective layer 310 is also provided on the side of the insulating layer 320 away from the substrate 110. The protective layer 310 covers the metal wire 410 and is used to protect the metal wire 410.

[0066] Figure 8 is a cross-sectional view of another multi-dimensional force sensor provided by an embodiment of the present invention. As shown in Figure 8 , this embodiment further improves upon the previous embodiment by providing a stress film 510 on the bottom surface and inner wall of the first groove 111. The stress film 510 imparts tensile stress, compensating for stress generated on the substrate 110 during sensor operation. This prevents substrate 110 from cracking under external forces and increases the device's operating pressure range. The portions of this embodiment that are identical to the previous embodiments are not further described here.

[0067] Figure 9 is a cross-sectional view of another multi-dimensional force sensor provided by an embodiment of the present invention. As shown in Figure 9, a second highly doped wire 117 is provided at the outer edge of the first side surface of the substrate 110. This embodiment is further improved on the basis of the previous embodiment. A lateral opening 311 is formed on the protective layer 310 and the insulating layer 320 on the side wall of the first groove 111, exposing a portion of the second highly doped wire 117.

[0068] Exemplarily, as shown in FIG9 , a stress film 510 is provided on the bottom surface and inner wall of the first groove 111, and the stress film 510 is a metal film. The stress film 510 extends into the lateral opening 311 and is connected to the exposed portion of the second highly doped wire 117. Exemplarily, the stress film 510 has tensile stress, which can compensate for the stress generated on the substrate 110 during the operation of the sensor, thereby suppressing the rupture of the substrate 110 under the action of external force and improving the operating pressure range of the device. In addition, a constant reference potential can be applied to the second highly doped wire 117, so that the stress film 510 forms a large area of ​​equipotential, forming a shielding layer to shield the interference of external signals. The parts of this embodiment that are the same as those in the embodiment are not repeated here.

[0069] FIG10 is a flow chart of a method for manufacturing a multi-dimensional force sensor according to an embodiment of the present invention. The figure is a cross-sectional view taken along section line BB. As shown in FIG10 , the method for manufacturing the multi-dimensional force sensor includes:

[0070] S101. Provide a base and a pedestal.

[0071] For example, the material of the base and the base can be <100> A silicon substrate grown in a crystal direction, wherein <100> The crystal direction is a direction perpendicular to the first side surface of the substrate.

[0072] S102 , forming a varistor in the beam region of the first side surface of the substrate.

[0073] Exemplarily, as shown in FIG10 , ion implantation is used to form a varistor 114 on the first side of the substrate 110. Exemplarily, a photoresist is formed on the first side of the substrate 110 in advance, and the photoresist is exposed and developed to form a mask for ion implantation. Boron ions are then implanted into the first side of the substrate 110 to form the varistor 114 on the substrate 110.

[0074] S103. Remove part of the substrate to form a first groove, an island structure and a beam structure, wherein the island structure is arranged at the center of the first groove, the island structure is connected to the inner wall of the first groove through multiple beam structures, and the surfaces of both ends of the beam structure are provided with varistors, and the multiple varistors are electrically connected.

[0075] For example, as shown in FIG10 , a portion of the substrate 110 is removed to form a first groove 111, an island structure 112, and a beam structure 113, wherein the island structure 112 is arranged at the center of the first groove 111, and the island structure 112 is connected to the inner wall of the first groove 111 through multiple beam structures 113, and the piezoresistor 114 is located on the surface of both ends of the beam structure 113. For example, the specific structure of the sensor body has been described in detail in the aforementioned embodiment, and the embodiment of the present invention will not be repeated here. For example, a photoresist can be formed on the first side surface of the substrate 110 in advance, and the photoresist is exposed and developed to form a mask. Then, the substrate 110 is etched to remove a portion of the substrate to form the first groove 111, the island structure 112, and the beam structure 113.

[0076] S104: Process the front surface of the base, remove part of the base, and form a second groove on the front surface of the base.

[0077] 10 , the front surface of the base 200 is processed to remove a portion of the base, and the second groove 210 is formed on the front surface of the base 200. For example, a photoresist may be formed on the front surface of the base 200 in advance, and the photoresist is exposed and developed to form a mask. The base 200 is then etched to remove a portion of the base to form the second groove 210.

[0078] S105 , bonding the first side surface of the substrate to the front surface of the base, with the outer edge of the substrate supported on the outer edge of the base.

[0079] Exemplarily, as shown in FIG10 , the first side surface of the substrate 110 is bonded to the front surface of the base 200 , and the outer edge of the substrate 110 (ie, the portion outside the first groove 111 ) is supported on the outer edge of the base 200 (ie, the portion outside the second groove 210 ).

[0080] S106. A connector for connecting an external force transmission component is formed on the second side surface of the substrate, the second side surface is opposite to the first side surface, and a vertical projection of the connector on the first side surface overlaps with a vertical projection of the island structure on the first side surface.

[0081] Exemplarily, as shown in FIG10 , a connector 120 for connecting an external force-conducting member is formed on the second side surface of the substrate 110. The second side surface is opposite to the first side surface, and the vertical projection of the connector 120 on the first side surface overlaps with the vertical projection of the island structure 112 on the first side surface. Exemplarily, the vertical projection of the connector 120 on the first side surface coincides with the vertical projection of the island structure 112 on the first side surface. Exemplarily, a photoresist is formed on the second side surface of the substrate 110 in advance, the photoresist is exposed and developed to form a mask, and then the substrate 110 is etched to remove part of the substrate to form the connector 120. Exemplarily, the specific structure of the connector 120 has been described in detail in the aforementioned embodiment, and the embodiment of the present invention will not be repeated here.

[0082] The specific structure and working principle of the multi-dimensional force sensor have been described in detail in the aforementioned embodiments, and will not be repeated here in the embodiments of the present invention.

[0083] The following describes in detail a method for preparing a multi-dimensional force sensor by taking a specific embodiment as an example.

[0084] FIG11 to FIG14 are flow charts of another method for preparing a multi-dimensional force sensor according to an embodiment of the present invention. The figure is a cross-sectional view taken along section line BB. As shown in FIG11 to FIG14 , the preparation process is as follows:

[0085] The substrate 110 material can be <100> A silicon substrate grown in a crystal direction, wherein <100> The crystal direction is a direction perpendicular to the first side surface of the substrate.

[0086] The substrate 110 is sequentially cleaned, dried, and thermally oxidized to form an ion scattering layer 116 on the surface of the substrate 110. For example, the substrate 110 is a silicon substrate, and the ion scattering layer 116 is silicon dioxide.

[0087] An alignment mark (not shown in the figure) is formed on the edge of the first side surface of the substrate 110 to facilitate alignment in subsequent processes.

[0088] Ions are implanted into the first side of the substrate 110 to form the varistor 114 on the substrate 110 below the ion scattering layer 116. For example, a photoresist is pre-formed on the surface of the ion scattering layer 116, and the photoresist is exposed and developed to form a mask for ion implantation. Boron ions are then implanted into the first side of the substrate 110 to form the varistor 114 on the substrate 110 below the ion scattering layer 116. The ion scattering layer 116 scatters the ion beam, preventing ions from being implanted deep into the substrate 110. After the ion implantation, the surface photoresist is removed, and the substrate is cleaned and dried.

[0089] Highly doped ions are implanted into the first side of the substrate 110, forming a plurality of first highly doped wires 115 and second highly doped wires 117 on the substrate 110 below the ion scattering layer 116. The first highly doped wires 115 are disposed at both ends of the varistor 114 and are in contact with and connected to the varistor 114. The second highly doped wires 117 are disposed at the outer edge of the first side of the substrate 110. Exemplarily, a photoresist is pre-formed on the surface of the ion scattering layer 116, exposed and developed to form a mask for ion implantation, and then highly doped ions are implanted into the first side of the substrate 110, forming a plurality of first highly doped wires 115 and second highly doped wires 117 on the substrate 110 below the ion scattering layer 116. The ion scattering layer 116 scatters the ion beam, preventing ions from being implanted into deeper layers of the substrate 110. After the ion implantation, the surface photoresist is removed, and the substrate is cleaned and dried.

[0090] High temperature annealing is used to activate the ions in the varistor 114 , the first highly doped wire 115 and the second highly doped wire 117 .

[0091] The ion scattering layer 116 on the surface of the substrate 110 is removed, and an insulating layer 320 is formed on the first side of the substrate 110. The insulating layer 320 covers the varistor 114, the first highly doped wire 115, and the second highly doped wire 117. Exemplarily, the ion scattering layer 116 on the surface of the substrate 110 is removed by etching with hydrofluoric acid. After cleaning and drying, the insulating layer 320 is formed on the first side of the substrate 110 by plasma-enhanced chemical vapor deposition. Exemplarily, the insulating layer 320 is silicon dioxide.

[0092] The insulating layer 320 is opened to form a via hole 321 in the insulating layer 320, exposing a portion of the first highly doped conductive line 115 and the second highly doped conductive line 117. For example, a photoresist is formed on the surface of the insulating layer 320 in advance, and the photoresist is exposed and developed to form a mask. The insulating layer 320 is then etched to form the via hole 321 in the insulating layer 320. After etching, the surface photoresist is removed, and the layer is cleaned and dried.

[0093] Metal wires 410 are formed on the surface of the insulating layer 320 away from the substrate 110. Metal wires 410 extend into vias 321 and connect to the first highly-doped wire 115 and the second highly-doped wire 117. Metal wires 410 extend outside the sensor body 100 for connection to external circuitry. For example, a photoresist is pre-formed on the surface of the insulating layer 320 away from the substrate 110. The photoresist is exposed and developed to form a mask. Then, magnetron sputtering is used to form metal wires 410 on the surface of the insulating layer 320 away from the substrate 110. The photoresist is then removed, and the surface is cleaned and dried.

[0094] A protective layer 310 is formed on the surface of the insulating layer 320 away from the substrate, and covers the metal wire 410. For example, the protective layer 310 is formed on the surface of the insulating layer 320 away from the substrate by plasma enhanced chemical vapor deposition. For example, the protective layer 310 is silicon dioxide.

[0095] The substrate 110, the insulating layer 320, and the protective layer 310 are etched to remove a portion of the substrate, as well as portions of the insulating layer and the protective layer on the substrate, to form a plurality of sub-grooves 1111. The plurality of sub-grooves 1111 are combined to form the first groove 111. The regions between the plurality of sub-grooves 1111 form the island structure 112 and the beam structure 113. Exemplarily, a photoresist 610 is pre-formed on the surface of the protective layer 310, and the photoresist is exposed and developed to form a mask. Then, a deep silicon etch is performed on the beam region A2 to remove a portion of the substrate, as well as portions of the insulating layer and the protective layer on the substrate, to form the sub-grooves 1111.

[0096] The polymer 1112 formed on the inner wall of the sub-groove 1111 by the etching process is removed. During the deep silicon etching process, in order to form a sub-groove with good verticality, an etching-passivation alternating method is used for etching. During the deep silicon etching process with the alternating etching-passivation method, polymer 1112 will form on the sidewall of the sub-groove 1111, affecting the subsequent side etching. Therefore, in the embodiment of the present invention, oxygen plasma cutting or silicon isotropic etching can be used to remove the polymer 1112 on the sidewall of the sub-groove 1111.

[0097] The inner wall of the sub-groove 1111 is side-etched to remove a portion of the insulating layer and a portion of the protective layer on the inner wall of the sub-groove 1111, forming a lateral opening 311 on the inner wall of the sub-groove 1111, exposing a portion of the second highly doped conductive line 117. Exemplarily, the insulating layer 320 and the protective layer 310 are both made of silicon dioxide. Silicon dioxide can be isotropically etched, for example, using HF gas to side-etch the silicon dioxide, removing a portion of the insulating layer and a portion of the protective layer on the inner wall of the sub-groove 1111, forming a lateral opening 311 on the inner wall of the sub-groove 1111, exposing a portion of the second highly doped conductive line 117.

[0098] A stress film 510 is formed on the bottom and inner wall of the sub-groove 1111. The stress film 510 extends into the lateral opening 311 and connects to the exposed portion of the second highly doped conductive line 117. Exemplarily, the stress film 510 is formed on the photoresist 610 and on the bottom and inner wall of the sub-groove 1111 by magnetron sputtering. Due to the presence of the lateral opening 311, the stress film 510 on the side wall of the sub-groove 1111 is disconnected and extends into the lateral opening 311 to connect to the exposed portion of the second highly doped conductive line 117. Exemplarily, the stress film 510 has a tensile stress, which can compensate for the stress generated on the substrate 110 during sensor operation, thereby suppressing cracking of the substrate 110 under external forces and increasing the operating pressure range of the device. In one embodiment, the stress film 510 is a metal film that can apply a constant reference potential to the second highly doped conductive line 117, thereby forming a large-area equipotential across the stress film 510, forming a shielding layer to block interference from external signals.

[0099] The photoresist 610 is stripped off. For example, an organic solution may be used to remove the photoresist 610 . The presence of the side opening 311 facilitates the stripping of the photoresist 610 .

[0100] The front surface of the base 200 is processed to remove a portion of the base, and the second groove 210 is formed on the front surface of the base 200. For example, a photoresist can be formed on the front surface of the base 200 in advance, and the photoresist is exposed and developed to form a mask. Then, the base 200 is etched to remove a portion of the base to form the second groove 210. After etching, the photoresist on the surface is removed, and the base is cleaned and dried.

[0101] The first side surface of the substrate 110 is bonded to the front surface of the base 200 , and the outer edge of the substrate 110 (ie, the portion outside the first groove 111 ) is supported on the outer edge of the base 200 (ie, the portion outside the second groove 210 ).

[0102] The surfaces of the base 200 and the substrate 110 are ground to reduce the thickness of the base 200 and the substrate 110 to a target thickness. After grinding, the base 200 and the substrate 110 are polished.

[0103] Tin metal 121 is deposited on the second side of the substrate 110 to form a pattern corresponding to the connector.

[0104] The second side of the substrate 110 is etched to form a connector 120. For example, a photoresist can be formed on the second side of the substrate 110 in advance, and the photoresist is exposed and developed to form a mask. Then, the second side of the substrate 110 is etched using deep silicon etching to remove part of the substrate to form the connector 120. The second side is opposite to the first side, and the vertical projection of the connector 120 on the first side overlaps with the vertical projection of the island structure 112 on the first side. For example, the vertical projection of the connector 120 on the first side coincides with the vertical projection of the island structure 112 on the first side. After etching, the photoresist on the surface is removed, and the components are cleaned and dried. For example, the specific structure of the connector 120 has been described in detail in the aforementioned embodiment, and the embodiments of the present invention will not be repeated here.

[0105] Figure 15 is a schematic diagram of the connection between a connector and an external force conduction component. As shown in Figure 15, the surface of the connector 120 has a layer of tin metal 121, and the external force conduction component 810 can be an aluminum material. The external force conduction component 810 is placed on the connector 120 and baked at a high temperature to make the tin and aluminum eutectic to form an aluminum-tin alloy.

[0106] Figure 16 is a schematic diagram of the connection between another connector and an external force conduction component. As shown in Figure 16, tin is not deposited on the surface of the connector 120. Glue is dispensed on the surface of the connector 120 to form a glue film layer 122. Then, the external force conduction component 810 is placed on the connector 120 and cured.

[0107] It should be noted that the etching process in the above embodiment is described by taking wet etching as an example. In other embodiments of the present invention, dry etching may also be used, and the embodiment of the present invention is not limited here.

[0108] In the description of this document, it should be understood that the terms "up", "down", "left", "right", and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0109] In this specification, reference to terms such as "one embodiment" or "example" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example.

[0110] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0111] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and are not to be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will readily conceive of other specific embodiments of the present invention without inventive effort, and such embodiments will fall within the scope of protection of the present invention.

Claims

1. A multi-dimensional force sensor, characterized in that: include: A sensor body, the sensor body comprising a substrate, a first groove is provided on a first side of the substrate, an island structure is provided at the center of the first groove, the island structure is connected to the inner wall of the first groove through a plurality of beam structures, piezoresistors are provided on surfaces at both ends of the beam structure, and the plurality of piezoresistors are electrically connected, a connector protruding from the second side is provided on the second side of the substrate, the connector is used to connect an external force conducting member, the second side is opposite to the first side, and a vertical projection of the connector on the first side overlaps with a vertical projection of the island structure on the first side; The base has a second groove on its front side, the first side of the base is bonded to the front side of the base, and the outer edge of the base is supported on the outer edge of the base.

2. The multi-dimensional force sensor according to claim 1, characterized in that: An insulating layer and a protective layer are also provided between the sensor body and the base, and the insulating layer covers the first side surface of the substrate, the island structure and the beam structure; A first highly doped wire is also disposed at the outer edge of the first side surface of the substrate, and the first highly doped wire is disposed at both ends of the varistor and connected to the varistor; A metal wire is disposed on a side of the insulating layer away from the substrate, the metal wire penetrates the insulating layer and is in ohmic contact with the first highly doped wire, and the plurality of varistors are electrically connected via the metal wire; The protection layer covers the metal wire.

3. The multi-dimensional force sensor according to claim 2, characterized in that: A second highly doped conductive line is disposed at the outer edge of the first side surface of the substrate, and a lateral opening is formed on the sidewall of the first groove to expose a portion of the second highly doped conductive line.

4. The multi-dimensional force sensor according to claim 3, characterized in that: A stress film is provided on the bottom surface and inner wall of the first groove.

5. The multi-dimensional force sensor according to claim 4, characterized in that: The stress film is a metal film, and the stress film extends into the lateral opening and is connected to the exposed portion of the second highly-doped conductive line.

6. The multi-dimensional force sensor according to any one of claims 1 to 5, characterized in that: The connector is a hollow structure, a first end of the connector is connected to the second side surface of the substrate, and a second end of the connector is open.

7. The multi-dimensional force sensor according to any one of claims 1 to 5, characterized in that: The base is along <100> The silicon substrate is grown in a crystal direction, and the edges of the first groove, the island structure and the beam structure are aligned with the substrate. <110> The crystal direction and the <11(-)0> crystal direction are not parallel.

8. A method for preparing a multi-dimensional force sensor, characterized in that: include: providing a base and a foundation; forming a varistor on a first side of the substrate; Removing part of the substrate to form a first groove, an island structure and a beam structure, wherein the island structure is arranged at the center of the first groove, the island structure is connected to the inner wall of the first groove through a plurality of beam structures, varistors are arranged on the surfaces of both ends of the beam structure, and the plurality of varistors are electrically connected; Processing the front side of the base, removing part of the base, and forming a second groove on the front side of the base; Bonding the first side surface of the substrate to the front surface of the base, with the outer edge of the substrate supported on the outer edge of the base; A connector for connecting an external force transmission component is formed on the second side of the substrate, the second side is opposite to the first side, and a vertical projection of the connector on the first side overlaps with a vertical projection of the island structure on the first side.

9. The method for preparing the multi-dimensional force sensor according to claim 8, characterized in that: A varistor is formed on the first side of the substrate, comprising: The substrate is sequentially cleaned, dried, and thermally oxidized to form an ion scattering layer on the surface of the substrate; Ions are implanted into the first side of the substrate to form a varistor on the substrate below the ion scattering layer.

10. The method for preparing a multi-dimensional force sensor according to claim 9, characterized in that: After forming a varistor in the beam region of the first side of the substrate, the method further comprises: Performing ion implantation on the first side of the substrate to form a plurality of first highly doped wires and second highly doped wires on the substrate below the ion scattering layer, wherein the first highly doped wires are disposed at both ends of the varistor and connected to the varistor, and the second highly doped wires are located at the outer edge of the first side of the substrate; removing the ion scattering layer on the surface of the substrate; forming an insulating layer on a first side surface of the substrate, wherein the insulating layer covers the varistor, the first highly doped wire, and the second highly doped wire; Opening the insulating layer to form via holes on the insulating layer to expose a portion of the first highly doped wire and a portion of the second highly doped wire; Forming a metal wire on a surface of the insulating layer away from the substrate, the metal wire extending into the via hole and in ohmic contact with the first highly doped wire and the second highly doped wire, and the plurality of varistors are electrically connected via the metal wire; A protection layer is formed on a surface of the insulating layer away from the substrate, and the protection layer covers the metal wire.

11. The method for preparing a multi-dimensional force sensor according to claim 10, characterized in that: Removing part of the substrate to form a first groove, an island structure and a beam structure, including: Etching the beam region to remove part of the substrate in the beam region, as well as part of the insulating layer and part of the protective layer on the substrate, to form a plurality of sub-grooves in the beam region, wherein the plurality of sub-grooves are combined to form the first groove, and the region between the plurality of sub-grooves forms the island structure and the beam structure; removing the polymer formed on the inner wall of the sub-groove by etching process; Removing part of the insulating layer and part of the protective layer on the inner wall of the sub-groove, forming a lateral opening on the inner wall of the sub-groove, and exposing part of the second highly doped wire; A stress film is formed on the bottom surface and inner wall of the sub-groove, and the stress film extends into the lateral opening and is connected to the exposed portion of the second highly doped conductive line.

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