Wafer level enhanced electric field sensor and method of making same

Abstract

The disclosure provides a wafer-level enhanced electric field sensor and a preparation method thereof, which can be applied to the technical field of electric field sensors. The wafer-level enhanced electric field sensor and the preparation method thereof comprise: a substrate for supporting an electric field sensitive structure, the surface of the substrate being provided with an anchor point; the electric field sensitive structure is arranged on the substrate and is used for sensing a to-be-measured electric field, wherein the electric field sensitive structure comprises any one of the following: a charge sensing type structure, an electrostatic force type structure, a piezoelectric type structure, a piezoresistive type structure and a guided charge type structure; a field enhancement cover plate is located above the electric field sensitive structure and is used for concentrating the to-be-measured electric field so as to enhance the electric field intensity acting on the electric field sensitive structure; and an insulating support structure layer is arranged at the edge of the substrate and is used for connecting the field enhancement cover plate and the substrate.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of electric field sensor, and more particularly to a wafer-level enhanced electric field sensor and a preparation method thereof. BACKGROUND

[0002] Electric field detection is widely used in many fields, such as aerospace, meteorology, power, industrial production, etc. The traditional electric field sensor improves the test sensitivity to the measured electric field by improving the sensitive mechanism of the sensor or optimizing the sensitive structure in the sensor. Although the traditional improvement method can improve the detection sensitivity of the electric field sensor to the electric field, with the improvement of technology and the repeated excavation of the mechanism and structure of the sensor, it is difficult for the researchers to further improve the sensitivity of the electric field sensor from the sensitive mechanism or the sensitive structure.

[0003] In the process of realizing the above-mentioned inventive concept, the inventors found that in the related art, due to the increasingly improved sensitive mechanism and sensitive structure of the electric field sensor, it is difficult to further improve the electric field sensor, the response of the electric field sensor to the measured electric field is small, and the sensitivity of the electric field sensor is low. SUMMARY

[0004] In view of the above problems, the present disclosure provides a wafer-level enhanced electric field sensor and a preparation method thereof.

[0005] According to a first aspect of the present disclosure, a wafer-level enhanced electric field sensor is provided, comprising: a substrate for supporting an electric field sensitive structure, a surface of the substrate being provided with an anchor point; an electric field sensitive structure disposed on the substrate for sensing a measured electric field, wherein the electric field sensitive structure comprises any one of: a charge sensing structure, an electrostatic force structure, a piezoelectric structure, a piezoresistive structure and a guided charge structure; a field enhancement cover plate located above the electric field sensitive structure for concentrating the measured electric field so as to enhance the electric field strength acting on the electric field sensitive structure; an insulating support structure layer disposed at the edge of the substrate for connecting the field enhancement cover plate and the substrate.

[0006] According to an embodiment of the present disclosure, the field enhancement cover plate comprises a cover plate and an enhancement structure; the upper surface of the cover plate is perpendicular to the measured electric field, and the lower surface of the cover plate is in contact with the insulating support structure layer for improving the electric field strength; the enhancement structure is located directly above the electric field sensitive structure, and the enhancement structure is located on the upper surface of the cover plate and / or the lower surface of the cover plate for concentrating the measured electric field.

[0007] According to an embodiment of the present disclosure, a middle layer insulating region is included between the cover plate and the enhancement structure, the middle layer insulating region is a high dielectric constant material, and the middle layer insulating region is used to improve the capacitance value between the cover plate and the enhancement structure so as to improve the potential of the structure below the middle layer insulating region.

[0008] According to an embodiment of the present disclosure, the field enhancement cover plate further comprises a conductor column in the middle layer insulation region, for connecting the cover plate and the enhancement structure.

[0009] According to an embodiment of the present disclosure, the cover plate is directly connected with the enhancement structure, for concentrating the electric field to be measured, so as to improve the electric field strength.

[0010] According to an embodiment of the present disclosure, the shape of the enhancement structure comprises any one of the following: circular truncated cone, prism, truncated prism, cylinder, cone.

[0011] According to an embodiment of the present disclosure, the cover plate is composed of a composite material with a conductive layer on the outermost layer, or composed of one or more conductor materials; the enhancement structure is composed of a composite material with a conductive layer on the outermost layer, or composed of one or more layers of conductor materials; the insulation support structure layer is composed of one or more insulating materials, or composed of a composite material with an insulating material on the outermost layer.

[0012] The second aspect of the present disclosure provides a preparation method of a wafer-level enhanced electric field sensor, comprising: etching a groove on a silicon wafer by a photolithography etching process to obtain a cover plate containing the groove, wherein the groove represents the position of the insulation support structure layer reserved on the cover plate; filling glass medium in the groove by a glass reflow process, and removing the upper and lower excess glass layer and silicon layer by grinding and polishing to obtain an insulation support structure layer connected with the cover plate; etching the cover plate by a photolithography etching process to obtain an enhancement structure, and thinning the enhancement structure by photolithography etching to obtain a field enhancement structure connected with the insulation support structure layer; etching on a device layer of a silicon-on-insulator by a photolithography etching process to obtain a substrate connected with a sensitive structure; etching the silicon oxide layer in the substrate connected with the electric field sensitive structure by a wet etching process to release the electric field sensitive structure in the substrate, so as to facilitate the free vibration of the electric field sensitive structure; aligning the insulation support structure layer and the substrate, and then performing bonding and dicing operations to obtain a wafer-level enhanced electric field sensor.

[0013] The third aspect of the present disclosure provides an electric field sensor, comprising: a wafer-level field enhanced electric field sensor according to any one of claims 1 to 6; or a wafer-level field enhanced electric field sensor obtained by the preparation method of claim 7.

[0014] According to an embodiment of the present disclosure, the electric field sensor further comprises a two-dimensional or three-dimensional electric field sensor composed of a plurality of electric field sensitive structures, for measuring two-dimensional or three-dimensional electric field or voltage.

[0015] According to the wafer-level enhanced electric field sensor and the preparation method thereof, the wafer-level enhanced electric field sensor comprises a substrate, an electric field sensitive structure, a field enhancement cover plate and an insulating support structure layer, the electric field sensitive structure is arranged on the substrate, the lower surface of the insulating support structure layer is bonded and connected with the substrate at a bonding area, the upper surface of the insulating support structure layer is connected with the field enhancement cover plate, so that the field enhancement cover plate is located above the electric field sensitive structure, at the same time, since the outermost layer of the insulating support structure layer is an insulating material, the electric field sensor can be kept electrically insulated between the field enhancement cover plate and the substrate, the field enhancement cover plate concentrates the to-be-measured electric field first, the electric potential of the to-be-measured electric field after the field enhancement cover plate is increased, and the electric field intensity is increased, so that the electric field intensity of the to-be-measured electric field acting on the electric field sensitive structure is enhanced, the sensitivity of the electric field sensor is improved, and the wafer-level enhanced electric field sensor has a simple structure and is easy to prepare, realizes wafer-level packaging of the electric field sensor, further improves the concentration effect of the to-be-measured electric field, and improves the sensitivity of the electric field sensor. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which:

[0017] Figure 1 A structure schematic diagram of a wafer-level enhanced electric field sensor according to an embodiment of the present disclosure is schematically shown;

[0018] Figure 2 A structure schematic diagram of an electric field sensitive structure according to an embodiment of the present disclosure is schematically shown;

[0019] Figure 3 A structure schematic diagram of a field enhancement cover plate according to an embodiment of the present disclosure is schematically shown;

[0020] Figure 4 A structure schematic diagram of a field enhancement cover plate according to another embodiment of the present disclosure is schematically shown;

[0021] Figure 5 A structure schematic diagram of a field enhancement cover plate according to still another embodiment of the present disclosure is schematically shown;

[0022] Figure 6 A structure schematic diagram of a field enhancement cover plate according to yet another embodiment of the present disclosure is schematically shown;

[0023] Figure 7 A flow chart of a preparation method of a wafer-level enhanced electric field sensor according to an embodiment of the present disclosure is schematically shown;

[0024] Figure 8 A schematic diagram of a preparation method of a wafer-level enhanced electric field sensor according to an embodiment of the present disclosure is schematically shown.

[0025] Reference Signs:

[0026] 101 - substrate, 102 - electric field sensitive structure, 103 - field enhancement cover plate, 104 - insulating support structure layer, 201 - shield electrode, 202 - sense electrode, 203 - drive electrode, 204 - spring beam, 205 - anchor point, 301 - cover plate, 302 - enhancement structure, 401 - middle insulating region, 501 - conductor post, 601 - first enhancement structure, 602 - second enhancement structure, 801 - silicon, 802 - silicon dioxide. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood, however, that the description which follows is merely illustrative and is not intended to limit the scope of the present disclosure. In the following detailed description of embodiments of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. However, it would be apparent to one skilled in the art that the embodiments of the present disclosure can be practiced without these specific details. In other instances, well-known structures and functions have not been described in detail in order to avoid obscuring aspects of the present disclosure.

[0028] The terms used herein are merely used to describe specific embodiments and are not intended to limit the present disclosure. The terms "include", "comprise" and the like used herein indicate the presence of the described features, steps, operations, and / or components but do not preclude the presence or addition of one or more other features, steps, operations, or components.

[0029] All terms used herein, including technical and scientific terms, have the same meanings as those generally understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having meanings that are consistent with the context of the present description, and should not be interpreted in an idealized or overly formal way.

[0030] In the case of using expressions similar to "at least one of A, B, and C, etc.", it should generally be interpreted to include any of the combinations of the items enumerated in the list (e.g., "a system having at least one of A, B, and C" should include a system having A alone, a system having B alone, a system having C alone, a system having both A and B, a system having both A and C, a system having both B and C, and / or a system having A, B, and C together, etc.).

[0031] In the technical solutions of the present application, the user information (including but not limited to user personal information, user image information, user equipment information such as location information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved are all information and data authorized by the user or authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of related data comply with relevant laws, regulations and standards, necessary security measures are taken, public order and good customs are not violated, and appropriate operation portals are provided for the user to choose authorization or refusal.

[0032] With the development of electric field detection technology, electric field detection is applied in many fields, such as aerospace, meteorology, power, dangerous chemicals, and industrial production. The electric field sensor developed by the traditional micro-electro-mechanical system has small size, light weight and low cost, but the sensitivity of the sensor is poor and cannot meet the current demand. On this basis, researchers further develop the sensitive mechanism and sensitive structure of the electric field sensor to improve the sensitivity of the electric field sensor.

[0033] However, with the development of technology, the difficulty of mining the sensitive mechanism of the electric field sensor is increasing, and the sensitive structure of the electric field sensor is also optimized and improved. It is difficult for researchers to improve the electric field sensor in the sensitive mechanism and the sensitive structure. The sensitivity of the electric field sensor is low. In the process of research and development, researchers found that in the related technology, due to the increasingly perfect sensitive mechanism and sensitive structure of the electric field sensor, it is difficult to further improve the electric field sensor, the response of the electric field sensor to the measured electric field is small, and the sensitivity of the electric field sensor is low.

[0034] Therefore, the embodiments of the present disclosure provide a wafer-level enhanced electric field sensor, which comprises: a substrate for supporting an electric field sensitive structure, the surface of the substrate is provided with an anchor point; an electric field sensitive structure arranged on the substrate for sensing a measured electric field, wherein the electric field sensitive structure comprises any one of the following: a charge sensing structure, an electrostatic force structure, a piezoelectric structure, a piezoresistive structure and a guided charge structure; a field enhancement cover plate located above the electric field sensitive structure for concentrating the measured electric field to enhance the electric field strength acting on the electric field sensitive structure; and an insulating support structure layer arranged at the edge of the substrate for connecting the field enhancement cover plate and the substrate.

[0035] The following will be described in detail Figures 1-6 The wafer-level enhanced electric field sensor of the disclosed embodiments will be described in detail.

[0036] According to the embodiments of the present disclosure, the wafer-level enhanced electric field sensor comprises a substrate, an electric field sensitive structure, a field enhancement cover plate and an insulating support structure layer.

[0037] According to an embodiment of the present disclosure, a substrate for supporting an electric field sensitive structure, a surface of the substrate is provided with an anchor point.

[0038] According to an embodiment of the present disclosure, the anchor point can be composed of one or more insulating materials.

[0039] According to an embodiment of the present disclosure, an edge of the upper surface of the substrate, i.e. the upper surface of the substrate around, is a bonding area, and the insulating support structure layer is bonded at the bonding area of the substrate.

[0040] According to an embodiment of the present disclosure, an electric field sensitive structure is arranged on the substrate for sensing an electric field to be measured.

[0041] According to an embodiment of the present disclosure, the electric field sensitive structure can be one of a charge sensing type structure, an electrostatic force type structure, a piezoelectric type structure, a piezoresistive type structure, a guided charge type structure and other structures.

[0042] According to an embodiment of the present disclosure, a field enhancement cover plate is arranged above the electric field sensitive structure for concentrating the electric field to be measured so as to enhance the electric field strength acting on the electric field sensitive structure.

[0043] According to an embodiment of the present disclosure, an insulating support structure layer is arranged at the edge of the substrate for connecting the field enhancement cover plate and the substrate.

[0044] According to an embodiment of the present disclosure, the upper surface of the insulating support structure layer is in contact with the lower surface of the field enhancement cover plate, and the lower surface of the insulating support structure layer is in contact with the substrate, and the insulating support structure layer is connected with the substrate by bonding.

[0045] According to an embodiment of the present disclosure, the insulating support structure layer can be used to maintain electrical insulation between the substrate and the field enhancement cover plate.

[0046] According to an embodiment of the present disclosure, the insulating support structure layer can be composed of one or more insulating materials, and the insulating support structure layer can also be composed of a composite material, and in the case that the insulating support structure layer is composed of a composite material, the outermost material of the composite material is an insulating material.

[0047] According to the embodiment of the present disclosure, the wafer-level enhanced electric field sensor comprises a substrate, an electric field sensitive structure, a field enhancement cover plate and an insulating support structure layer, the electric field sensitive structure is arranged on the substrate, the lower surface of the insulating support structure layer is bonded to the substrate at a bonding area, and the upper surface of the insulating support structure layer is connected to the field enhancement cover plate, so that the field enhancement cover plate is located above the electric field sensitive structure. At the same time, since the outermost layer of the insulating support structure layer is an insulating material, the electrical insulation between the field enhancement cover plate and the substrate can be maintained. The field enhancement cover plate first concentrates the to-be-measured electric field, and the electric potential of the to-be-measured electric field after passing through the field enhancement cover plate is increased, and the electric field strength is increased, so as to realize the enhancement of the electric field strength of the to-be-measured electric field acting on the electric field sensitive structure, improve the sensitivity of the electric field sensor, and the wafer-level enhanced electric field sensor has simple structure and is easy to prepare. The wafer-level packaging of the electric field sensor is realized, the concentration effect of the to-be-measured electric field is further improved, and the sensitivity of the electric field sensor is improved.

[0048] Figure 1 The structure schematic diagram of the wafer-level enhanced electric field sensor according to the embodiment of the present disclosure is schematically shown.

[0049] As Figure 1 shown, Figure 1 The structure of the wafer-level enhanced electric field sensor is shown, and the wafer-level enhanced electric field sensor comprises a substrate 101, an electric field sensitive structure 102, a field enhancement cover plate 103 and an insulating support structure layer 104. The upper surface of the insulating support structure layer 104 is connected to the field enhancement cover plate 103, the lower surface of the insulating support structure layer 104 is bonded at the bonding area of the substrate 101, the electric field sensitive structure 102 is bonded on the substrate 101, the to-be-measured electric field passes through the field enhancement cover plate 103 to improve the electric field strength, and the sensitivity of the wafer-level enhanced electric field sensor is further improved.

[0050] According to the embodiment of the present disclosure, the electric field sensitive structure is connected to the substrate through an anchor point.

[0051] Figure 2 The structure schematic diagram of the electric field sensitive structure according to the embodiment of the present disclosure is schematically shown.

[0052] As Figure 2As shown, the electric field sensitive structure is taken as an example of the charge sensing structure, and the electric field sensitive structure includes shielding electrodes 201, sensing electrodes 202, driving electrodes 203, elastic beams 204, and anchor points 205. The sensing electrodes 202 are connected to the substrate through the anchor points 205, two groups of the sensing electrodes 202 are distributed in the middle of the shielding electrodes 201, one group of the sensing electrodes 202 is distributed on the front side of the shielding electrodes 201, and the other group of the sensing electrodes 202 is distributed on the back side of the shielding electrodes 201. The sensing electrodes 202 are covered with combs, the combs on the sensing electrodes 202 are distributed alternately with the combs on the shielding electrodes 201, the shielding electrodes 201 are coplanar with the sensing electrodes 202, the elastic beams 204 are connected to the left and right sides of the shielding electrodes 201, the elastic beams 204 are connected to the anchor points 205, the elastic beams 204 are connected to the substrate through the anchor points 205, the left and right sides and the middle of the shielding electrodes 201 are covered with combs, the driving electrodes 203 are divided into four groups, each group of the driving electrodes is covered with combs, the combs in the middle of the shielding electrodes 201 are distributed alternately with the combs of the sensing electrodes 202, and the combs on the left and right sides of the shielding electrodes 201 are distributed alternately with the combs of the driving electrodes 203. The driving electrodes 203 can be one of electrostatic driving, piezoelectric driving, and thermal driving, or a combination thereof, which is not limited herein.

[0053] According to embodiments of the present disclosure, the field enhancement cover plate includes a cover plate and an enhancement structure.

[0054] According to embodiments of the present disclosure, the upper surface of the cover plate is perpendicular to the electric field to be measured, which is equivalent to that the upper surface of the cover plate faces the electric field to be measured, and the lower surface of the cover plate is in contact with the insulating support structure layer for improving the electric field strength.

[0055] According to embodiments of the present disclosure, the enhancement structure is located directly above the electric field sensitive structure, and the enhancement structure is located on the upper surface of the cover plate and / or the lower surface of the cover plate for concentrating the electric field to be measured.

[0056] According to embodiments of the present disclosure, the field enhancement cover plate can have three styles: one is that there is only one enhancement structure, and the enhancement structure is located on the lower surface of the cover plate; the other is that there is only one enhancement structure, and the enhancement structure is located on the upper surface of the cover plate; and the other is that there are two enhancement structures, one enhancement structure is located on the upper surface of the cover plate, and the other enhancement structure is located on the lower surface of the cover plate.

[0057] According to the embodiment of the present disclosure, since the field enhancement cover plate comprises the cover plate and the enhancement structure, the upper surface of the cover plate is perpendicular to the to-be-tested electric field so as to facilitate the to-be-tested electric field to enter the cover plate, the lower surface of the cover plate is connected with the insulating support structure layer, and the enhancement structure can be located on the upper surface of the cover plate or the lower surface of the cover plate. In the case where the to-be-tested electric field needs to be tested, the to-be-tested electric field passes through the cover plate and the enhancement structure, thereby realizing the concentration of the to-be-tested electric field, improving the electric potential of the to-be-tested electric field, increasing the electric field intensity of the to-be-tested electric field received by the electric field sensitive structure, and improving the sensitivity of the wafer-level enhanced electric field sensor.

[0058] According to the embodiment of the present disclosure, the middle layer insulating area can be arranged between the cover plate and the enhancement structure.

[0059] According to the embodiment of the present disclosure, the middle layer insulating area is made of high dielectric constant material, which is used to improve the capacitance value between the cover plate and the enhancement structure, so as to improve the electric potential of the structure below the middle layer insulating area.

[0060] According to the embodiment of the present disclosure, in the case where the enhancement structure is located on the lower surface of the cover plate, the cover plate can be attached to the upper surface of the middle layer insulating area, which is used to improve the electric potential of the lower surface of the cover plate. The middle layer insulating area is made of high dielectric constant material, which is used to improve the capacitance value between the cover plate and the enhancement structure, so as to improve the electric potential of the enhancement structure. Then, the enhancement structure is attached to the lower surface of the middle layer insulating area, which is used to reduce the distance between the enhancement structure and the electric field sensitive structure, so as to improve the electric field intensity.

[0061] According to the embodiment of the present disclosure, the field enhancement cover plate can further comprise a conductor column located in the middle layer insulating area, which is used to connect the cover plate and the enhancement structure, and further improve the electric field intensity.

[0062] According to the embodiment of the present disclosure, the cover plate can be directly connected with the enhancement structure, and can also be used to concentrate the to-be-tested electric field, so as to improve the electric field intensity.

[0063] According to the embodiment of the present disclosure, in the case where the middle layer insulating area is located between the cover plate and the enhancement structure, since the cover plate has a certain thickness, the voltage of the lower surface of the cover plate can be the electric potential of the to-be-tested electric field at the centroid coordinate of the cover plate. Compared with a plane without thickness, the electric potential of the lower surface of the cover plate is increased, the voltage of the lower surface of the cover plate is consistent with the voltage of the upper surface of the middle layer insulating area, the electric potential of the upper surface of the middle layer insulating area is also increased, the middle layer insulating area is made of high dielectric constant material, the capacitance between the cover plate and the enhancement structure is increased through the middle layer insulating area, the electric potential of the to-be-tested electric field at the lower surface of the middle layer insulating area and the enhancement structure is improved, and the electric field intensity of the to-be-tested electric field received by the electric field sensitive structure is increased, thereby improving the sensitivity of the electric field sensor.

[0064] According to the embodiment of the present disclosure, even if the cover plate is directly connected with the enhancement structure, due to the thickness of the cover plate, the voltage of the lower surface of the cover plate can be the potential of the electric field to be measured at the centroid coordinate of the cover plate, so that compared with a plane without thickness, the potential of the lower surface of the cover plate is increased, the voltage of the lower surface of the cover plate is consistent with the voltage of the upper surface of the enhancement structure, and the enhancement structure also has a certain thickness, so that the potential of the electric field to be measured of the enhancement structure can also be increased, the electric field intensity of the electric field to be measured received by the electric field sensitive structure is increased, and the sensitivity of the electric field sensor is improved.

[0065] According to the embodiment of the present disclosure, in the case that the enhancement structure is located on the lower surface of the cover plate, the cover plate can be attached to the upper surface of the middle layer insulating area, which is a high dielectric constant material, for increasing the potential of the lower surface of the cover plate, and for increasing the capacitance value between the cover plate and the enhancement structure, so as to increase the potential of the enhancement structure, and then the enhancement structure is attached to the lower surface of the middle layer insulating area, for reducing the distance between the enhancement structure and the electric field sensitive structure, so as to increase the electric field intensity.

[0066] According to the embodiment of the present disclosure, in the case that the enhancement structure is located on the lower surface of the cover plate, the overall structure shape of the field enhancement cover plate is in a "T" shape, and after the field enhancement cover plate is applied with the electric field to be measured, the potentials of the surfaces of the cover plate are the same, and due to the short distance between the enhancement structure and the electric field sensitive structure, according to the principle that the smaller the distance between two plates is under the same potential difference, the greater the inter-plate field intensity is, the electric field intensity of the electric field to be measured of the lower surface of the enhancement structure is increased, so that the electric field intensity of the electric field to be measured received by the electric field sensitive structure is increased, and the sensitivity of the electric field sensor is improved.

[0067] According to the embodiment of the present disclosure, in the case that the enhancement structure is located on the upper surface of the cover plate, due to the convex shape of the field enhancement cover plate, according to the principle that the electric field distribution inside a conductor is related to the shape of the surface of the conductor, the potential of the field enhancement cover plate and the electric field intensity above the electric field sensitive structure can be increased.

[0068] According to the embodiment of the present disclosure, in the case that there are two enhancement structures in total, one of which is located on the upper surface of the cover plate and the other of which is located on the lower surface of the cover plate, the enhancement structure on the upper surface of the cover plate can increase the potential of the surface of the cover plate, and the enhancement structure on the lower surface of the cover plate can reduce the distance between the enhancement structure and the cover plate, so as to further significantly increase the potential of the electric field to be measured, enhance the electric field intensity of the electric field to be measured, increase the intensity of the electric field to be measured received by the electric field sensitive structure, and improve the sensitivity of the electric field sensor.

[0069] According to the embodiment of the present disclosure, the shape of the enhancement structure can be any one of a circular truncated cone, a prism, a prismatic truncated cone, a cylinder, and a cone.

[0070] According to an embodiment of the present disclosure, the cover plate can be composed of a composite material with a conductive layer as the outermost layer, and the cover plate can also be composed of one or more conductor materials, which can include silicon and conductive metals.

[0071] According to an embodiment of the present disclosure, the reinforcing structure can be composed of a composite material with a conductive layer as the outermost layer, and the reinforcing structure can also be composed of one or more layers of insulating material and conductive material, and the reinforcing structure can also be composed of one or more layers of conductor material, which can include silicon and conductive metals, and the insulating material can include glass, ceramic, and plastic.

[0072] According to an embodiment of the present disclosure, the insulating support structure layer can be composed of one or more insulating materials, or composed of a composite material with an insulating material as the outermost layer.

[0073] Figure 3 The structural diagram of the field-enhanced cover plate according to an embodiment of the present disclosure is schematically shown.

[0074] As shown in Figure 3 , Figure 3 The structure of the field-enhanced cover plate is shown when the reinforcing structure is located on the lower surface of the cover plate, and the field-enhanced cover plate includes a cover plate 301 and a reinforcing structure 302, and the cover plate 301 is connected with the reinforcing structure 302 in a “T” shape. According to the principle that the smaller the distance between two electrode plates is, the greater the inter-plate field strength is under the same potential difference, the electric field strength of the to-be-measured electric field on the lower surface of the reinforcing structure is enhanced, so that the electric field strength of the to-be-measured electric field received by the electric field sensitive structure is increased, and the sensitivity of the electric field sensor is improved.

[0075] Figure 4 The structural diagram of the field-enhanced cover plate according to another embodiment of the present disclosure is schematically shown.

[0076] As shown in Figure 4 , Figure 4The specific structure of the field enhancement cover plate is shown in the case that the enhancement structure is located at the lower surface of the cover plate, the field enhancement cover plate comprises a cover plate 301, a middle layer insulating area 401 and an enhancement structure 302, the upper surface of the middle layer insulating area 401 is attached to the lower surface of the cover plate 301, the lower surface of the middle layer insulating area 401 is attached to the upper surface of the enhancement structure 302, the cover plate 301, the middle layer insulating area 401 and the enhancement structure 302 form a "sandwich" structure, because the cover plate has a certain thickness, the voltage of the lower surface of the cover plate can be the potential of the electric field to be measured at the centroid coordinate of the cover plate, so compared with a plane without thickness, the potential of the lower surface of the cover plate is increased, the voltage of the lower surface of the cover plate is consistent with the voltage of the upper surface of the middle layer insulating area, so the potential of the upper surface of the middle layer insulating area is also increased, the middle layer insulating area is composed of a high dielectric constant material, the size of the capacitance between the cover plate and the enhancement structure is increased through the middle layer insulating area, so as to increase the potential of the electric field to be measured at the lower surface of the middle layer insulating area and the enhancement structure, so that the electric field intensity of the electric field to be measured received by the electric field sensitive structure is increased, and the sensitivity of the electric field sensor is improved.

[0077] Figure 5 The structural schematic diagram of the field enhancement cover plate according to still another embodiment of the present disclosure is schematically shown.

[0078] As shown in Figure 5 , Figure 5 The field enhancement cover plate with a conductor column 501 is shown, the field enhancement cover plate comprises a cover plate 301, a middle layer insulating area 401, an enhancement structure 302 and the conductor column 501, the conductor column 501 is in the middle of the middle layer insulating area 401, the upper surface of the conductor column 501 is connected to the lower surface of the cover plate 301, the lower surface of the conductor column 501 is connected to the upper surface of the enhancement structure 302, further increasing the potential of the enhancement structure 302, and increasing the electric field intensity of the electric field to be measured.

[0079] Figure 6 The structural schematic diagram of the field enhancement cover plate according to still another embodiment of the present disclosure is schematically shown.

[0080] As shown in Figure 6 , Figure 6 The field enhancement cover plate is shown in the case that there are two enhancement structures in total, one enhancement structure is located at the upper surface of the cover plate, and the other enhancement structure is located at the lower surface of the cover plate, the field enhancement cover plate comprises a cover plate 301, a first enhancement structure 601 and a second enhancement structure 602, the first enhancement structure 601 can increase the potential of the surface of the cover plate 301, the second enhancement structure 602 can reduce the distance between the field enhancement cover plate and the cover plate 301, so as to further significantly increase the potential of the electric field to be measured, enhance the electric field intensity of the electric field to be measured, increase the intensity of the electric field to be measured received by the electric field sensitive structure, and improve the sensitivity of the electric field sensor.

[0081] Figure 7 A flowchart of a method for manufacturing a wafer-level enhanced electric field sensor is shown schematically.

[0082] As shown in Figure 7 The method for manufacturing a wafer-level enhanced electric field sensor of this embodiment includes operations S710-S760.

[0083] In operation S710, a groove is etched on a silicon wafer using a photolithography etching process to obtain a cover plate containing the groove.

[0084] According to an embodiment of the present disclosure, the groove is characterized as a position of an insulating support structure layer reserved on the cover plate.

[0085] According to an embodiment of the present disclosure, the cover plate can be composed of a silicon wafer.

[0086] In operation S720, a glass medium is filled in the groove using a glass reflow process, and the upper and lower excess glass layers and silicon layers are removed by grinding and polishing to obtain an insulating support structure layer connected to the cover plate.

[0087] According to an embodiment of the present disclosure, the insulating support structure layer can be composed of a glass medium.

[0088] In operation S730, the cover plate is etched by a photolithography etching process to obtain an enhancement structure, and the enhancement structure is thinned by photolithography etching to obtain a field enhancement structure connected to the insulating support structure layer.

[0089] In operation S740, the device layer of the silicon-on-insulator is etched using a photolithography etching process to obtain a substrate connected with an electric field sensitive structure.

[0090] According to an embodiment of the present disclosure, the silicon-on-insulator can be characterized as an SOI wafer, and the substrate can be composed of an SOI wafer.

[0091] According to an embodiment of the present disclosure, the electric field sensitive structure is etched on the device layer of the SOI wafer using a photolithography etching process.

[0092] In operation S750, the silicon oxide layer in the substrate connected with the sensitive structure is etched using a wet etching process to release the electric field sensitive structure in the substrate so as to facilitate free vibration of the electric field sensitive structure.

[0093] According to an embodiment of the present disclosure, the silicon oxide layer of the SOI device is etched using a wet etching process, so that part of the structure in the electric field sensitive structure is not connected to the substrate, thereby releasing the electric field sensitive structure so as to facilitate free vibration of the electric field sensitive structure to detect the measured electric field.

[0094] In operation S760, after the insulating support structure layer is aligned with the substrate, a bonding and dicing operation is performed to obtain a wafer-level enhanced electric field sensor.

[0095] According to the embodiment of the present disclosure, since the insulating support structure layer is arranged on the cover plate, then the cover plate is etched by using a photolithography etching process to obtain a field-enhanced cover plate connected with the insulating support structure layer, at the same time, the substrate is etched by using a photolithography etching process to obtain a substrate including an electric field sensitive structure, then the silicon dioxide layer in the substrate including the electric field sensitive structure is removed by using a wet etching process to release the electric field sensitive structure, the substrate and the insulating support structure layer are bonded together to obtain a wafer-level enhanced electric field sensor, the preparation of the wafer-level enhanced electric field sensor is realized, the wafer-level enhanced electric field sensor is that the field-enhanced cover plate is connected on the top of the silicon wafer through the insulating support structure layer, then the circuit and the electric field sensitive structure are connected to obtain an SOI wafer containing a plurality of electric field sensitive structures, then a dicing operation is performed to divide the SOI wafer containing a plurality of electric field sensitive structures to obtain an SOI wafer containing only one electric field sensitive structure, the wafer-level packaging of the electric field sensor is realized, and the wafer-level enhanced electric field sensor has a simple structure and is easy to prepare, the concentration effect of the measured electric field is enhanced, and the sensitivity of the wafer-level enhanced electric field sensor is significantly improved.

[0096] Figure 8 A schematic diagram prepared by a preparation method of a wafer-level enhanced electric field sensor according to an embodiment of the present disclosure is schematically shown.

[0097] As Figure 8 shown, Figure 8The process of preparing the wafer-level enhanced electric field sensor according to the preparation method of the wafer-level enhanced electric field sensor is shown. The white layer 801 represents the silicon layer, and the shaded layer 802 represents the silicon dioxide layer. First, a groove is etched on the silicon wafer by a photolithography etching process, and the position of the insulating support structure layer is reserved (a). Then, glass medium is filled in the groove by a glass reflow process, and the excess glass layer and silicon layer are removed by grinding and polishing to obtain the insulating support structure layer and connect it with the silicon wafer (b). Then, the silicon wafer with the insulating support structure layer is etched by a photolithography etching process to obtain the enhanced structure, and the enhanced structure is thinned by photolithography etching to obtain the field enhancement cover plate with the insulating support structure layer (c). At the same time of preparing the field enhancement cover plate and the insulating support structure layer (a)~(c), the electric field sensitive structure is prepared on the substrate. First, the electric field sensitive structure is etched on the SOI device layer on the SOI wafer by photolithography etching (d). Then, the silicon dioxide layer of the SOI device is etched by a wet etching process to release the electric field sensitive structure so that the electric field sensitive structure can vibrate freely (e). Finally, the field enhancement cover plate connected with the insulating support structure layer is aligned and bonded with the substrate containing the electric field sensitive structure, and then the wafer is cut to obtain the wafer-level enhanced electric field sensor.

[0098] According to an embodiment of the present disclosure, the electric field sensor can include the wafer-level field-enhanced electric field sensor as described above.

[0099] According to an embodiment of the present disclosure, the electric field sensor can include a two-dimensional or three-dimensional electric field sensor composed of a plurality of electric field sensitive structures for measuring a two-dimensional or three-dimensional electric field or voltage.

[0100] Those skilled in the art can understand that the features described in various embodiments and / or claims of the present disclosure can be combined or / and integrated in various combinations, even if such combinations or integrations are not explicitly described in the present disclosure. In particular, the features described in various embodiments and / or claims of the present disclosure can be combined and / or integrated in various combinations without departing from the spirit and teachings of the present disclosure. All such combinations and / or integrations fall within the scope of the present disclosure.

[0101] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not used to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A wafer level enhanced electric field sensor, comprising: a substrate for supporting an electric field sensitive structure, a surface of the substrate being provided with an anchor point; an electric field sensitive structure provided on the substrate for sensing a to-be-measured electric field, wherein the electric field sensitive structure comprises any one of the following: a charge sensing structure, an electrostatic force structure, a piezoelectric structure, a piezoresistive structure, and a guided charge structure; a field enhancement cover plate located above the electric field sensitive structure for concentrating the to-be-measured electric field so as to enhance the electric field strength acting on the electric field sensitive structure, the field enhancement cover plate comprising a cover plate and an enhancement structure, an upper surface of the cover plate being perpendicular to the to-be-measured electric field, a lower surface of the cover plate being in contact with an insulating support structure layer for improving the electric field strength; the enhancement structure being located directly above the electric field sensitive structure, the enhancement structure being located on the upper surface of the cover plate and / or the lower surface of the cover plate for concentrating the to-be-measured electric field, the cover plate being directly connected with the enhancement structure, or an intermediate insulating region being included between the cover plate and the enhancement structure, the cover plate and the enhancement structure being connectable through a conductor column provided in the intermediate insulating region for concentrating the to-be-measured electric field so as to improve the electric field strength, wherein the intermediate insulating region is a high dielectric constant material for improving the capacitance value between the cover plate and the enhancement structure so as to improve the potential of the structure below the intermediate insulating region; an insulating support structure layer provided at the edge of the substrate for connecting the field enhancement cover plate with the substrate.

2. The sensor of claim 1, wherein, The shape of the enhancement structure comprises any one of the following: a circular truncated cone, a prism, a prismatic truncated cone, a cylinder, and a cone.

3. The sensor of claim 1, wherein, The cover plate is composed of a composite material with a conductive layer as the outermost layer, or is composed of one or more conductor materials; The enhancement structure is composed of a composite material with a conductive layer as the outermost layer, or is composed of one or more conductor materials; The insulating support structure layer is composed of one or more insulating materials, or is composed of a composite material with an insulating material as the outermost layer. 4.A preparation method applied to the wafer level enhanced electric field sensor of any one of claims 1-3, comprising: etching a groove on a silicon wafer by using a photolithography etching process to obtain a cover plate containing the groove, wherein the groove represents the position of the insulating support structure layer reserved on the cover plate; filling a glass medium in the groove by using a glass reflow process, and removing the upper and lower excess glass layers and silicon layers by grinding and polishing to obtain an insulating support structure layer connected with the cover plate; etching the cover plate by a photolithography etching process to obtain an enhancement structure, and thinning the enhancement structure by a photolithography etching to obtain a field enhancement structure connected with the insulating support structure layer; etching on a device layer of a silicon-on-insulator by using a photolithography etching process to obtain a substrate connected with an electric field sensitive structure; etching a silicon oxide layer in the substrate connected with the sensitive structure by using a wet etching process to release the electric field sensitive structure in the substrate so as to facilitate the free vibration of the electric field sensitive structure. bonding and dicing operations after aligning the insulating support structure layer with the substrate to obtain the wafer level enhanced electric field sensor.

5. An electric field sensor comprising: The wafer level field enhanced electric field sensor according to any one of claims 1 to 3 or the wafer level field enhanced electric field sensor obtained by the method according to claim 4.

6. The electric field sensor of claim 5, wherein, The electric field sensor further comprises a two-dimensional or three-dimensional electric field sensor composed of a plurality of electric field sensitive structures for measuring a two-dimensional or three-dimensional electric field or voltage.

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