Wafer-level enhanced electric field sensor and preparation method thereof

Abstract

The invention provides a wafer-level enhanced electric field sensor and a preparation method thereof. The wafer-level enhanced electric field sensor can be applied to the technical field of electric field sensors. The wafer-level enhanced electric field sensor comprises a substrate used for supporting an electric field sensitive structure, and the surface of the substrate is provided with anchor points; the electric field sensitive structure is arranged on the substrate and used for sensing an electric field to be measured, and the electric field sensitive structure comprises any one of a charge sensing type structure, an electrostatic force type structure, a piezoelectric type structure, a piezoresistive type structure and a guide charge type structure; the field enhancement cover plate is positioned above the electric field sensitive structure and is used for concentrating the electric field to be measured so as to enhance the intensity of the electric field acting on the electric field sensitive structure; and the 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 sensors, and more specifically to a wafer-level enhanced electric field sensor and a preparation method thereof. Background Art

[0002] Electric field detection is widely used in many fields, such as aerospace, meteorology, electricity, industrial production, etc. Traditional electric field sensors improve the test sensitivity of the electric field to be measured by improving the sensitive mechanism of the sensor or optimizing the sensitive structure in the sensor. Although traditional improvement methods can improve the detection sensitivity of electric field sensors to electric fields, with the improvement of technology and repeated exploration of the mechanism and structure of sensors, it is difficult for R&D personnel to further improve the sensitivity of electric field sensors from the sensitive mechanism or sensitive structure.

[0003] In the process of realizing the above-mentioned inventive concept, the inventors found that due to the increasingly perfect sensitive mechanism and sensitive structure of electric field sensors in the related technology, it is difficult to make further improvements to the electric field sensors, the electric field sensors have a small response to the measured electric field, and the sensitivity of the electric field sensors is low. Summary of the invention

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

[0005] According to the first aspect of the present disclosure, a wafer-level enhanced electric field sensor is provided, comprising: a substrate, used to support an electric field sensitive structure, the surface of the substrate being provided with anchor points; an electric field sensitive structure, arranged on the substrate, and used to sense an electric field to be measured, wherein the electric field sensitive structure comprises any one of the following: a charge induction structure, an electrostatic force structure, a piezoelectric structure, a piezoresistive structure, and a charge-guided structure; a field enhancement cover plate, the field enhancement cover plate being located above the electric field sensitive structure, and being used to concentrate the electric field to be measured so as 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, and being used to connect the field enhancement cover plate and the substrate.

[0006] According to an embodiment of the present disclosure, the field enhancement cover plate includes a cover plate and a reinforcement structure; the upper surface of the cover plate is perpendicular to the electric field to be measured, and the lower surface of the cover plate is in contact with the insulating support structure layer, so as to increase the electric field strength; the reinforcement structure is located directly above the electric field sensitive structure, and the reinforcement structure is located on the upper surface of the cover plate and / or the lower surface of the cover plate, so as to concentrate the electric field to be measured.

[0007] According to an embodiment of the present disclosure, a middle insulating region is included between the cover plate and the reinforcement structure. The middle insulating region is made of a high dielectric constant material and is used to increase the capacitance between the cover plate and the reinforcement structure so as to increase the electrical potential of the structure below the middle insulating region.

[0008] According to an embodiment of the present disclosure, the field enhancement cover plate further comprises a conductor column, which is located in the middle-layer insulating region and is used to connect the cover plate and the enhancement structure.

[0009] According to an embodiment of the present disclosure, it also includes: the cover plate is directly connected to the reinforcement structure to concentrate 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 reinforcement structure includes any one of the following: a truncated cone, a prism, a truncated pyramid, a cylinder, and a cone.

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

[0012] The second aspect of the present disclosure provides a method for preparing a wafer-level enhanced electric field sensor, comprising: etching a groove on a silicon wafer using a photolithography process to obtain a cover plate containing the groove, wherein the groove represents the position of an insulating support structure layer reserved on the cover plate; filling a glass medium in the groove using a glass reflow process, and removing excess glass layers and silicon layers above and below by grinding and polishing to obtain an insulating support structure layer connected to the cover plate; etching the cover plate using a photolithography process to obtain an enhanced structure, and thinning the enhanced structure by photolithography to obtain a field enhancement structure connected to the insulating support structure layer; etching a device layer of silicon on an insulator using a photolithography 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 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; aligning the insulating support structure layer with the substrate, bonding and dicing operations are performed to obtain a wafer-level enhanced electric field sensor.

[0013] A 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 according to claim 7.

[0014] According to an embodiment of the present disclosure, the electric field sensor further includes 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.

[0015] According to the wafer-level enhanced electric field sensor and its preparation method disclosed in the present invention, the wafer-level enhanced electric field sensor includes 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 in the 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 electric field to be measured, and the electric potential of the electric field to be measured after passing through the field enhancement cover plate increases, and the electric field strength increases, thereby achieving the enhancement of the electric field strength of the electric field to be measured acting on the electric field sensitive structure, and improving the sensitivity of the electric field sensor. In addition, the wafer-level enhanced electric field sensor has a simple structure and is easy to prepare, and realizes wafer-level packaging of the electric field sensor, further improving the concentration effect of the electric field to be measured and improving the sensitivity of the electric field sensor. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

[0020] Figure 4 The schematic diagram shows the structure of a field enhancement cover plate according to another embodiment of the present disclosure;

[0021] Figure 5 The schematic diagram shows the structure of a field enhancement cover plate according to another embodiment of the present disclosure;

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

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

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

[0025] Reference numerals:

[0026] 101-substrate, 102-electric field sensitive structure, 103-field enhanced cover plate, 104-insulating support structure layer, 201-shielding electrode, 202-sensing electrode, 203-driving electrode, 204-elastic beam, 205-anchor point, 301-cover plate, 302-enhanced structure, 401-middle layer insulating region, 501-conductor column, 601-first enhanced structure, 602-second enhanced structure, 801-silicon, 802-silicon dioxide. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0028] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0029] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0030] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0031] In the technical solution of the present invention, the user information (including but not limited to user personal information, user image information, user device information, such as location information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved are all information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of relevant data comply with relevant laws, regulations and standards, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0032] With the development of electric field detection technology, electric field detection has been applied to many fields, such as aerospace, meteorology, electricity, hazardous chemicals, industrial production, etc. The electric field sensor developed by the traditional micro-electromechanical system is small in size, light in weight, and low in cost, but the sensitivity of the sensor is poor and cannot meet the current needs. On this basis, the R&D personnel further developed 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 science and technology, it is increasingly difficult to explore the sensitive mechanism of electric field sensors, and the sensitive structure of electric field sensors has been increasingly optimized. It is difficult for R&D personnel to improve the sensitive mechanism and sensitive structure of electric field sensors, and the sensitivity of electric field sensors is relatively low. During the R&D process, R&D personnel found that in related technologies, due to the increasingly perfect sensitive mechanism and sensitive structure of electric field sensors, it is difficult to make further improvements to electric field sensors, and electric field sensors have a small response to the measured electric field and a low sensitivity.

[0034] In view of this, an embodiment of the present disclosure provides a wafer-level enhanced electric field sensor, comprising: a substrate, used to support an electric field sensitive structure, and anchor points are arranged on the surface of the substrate; an electric field sensitive structure, arranged on the substrate, and used to sense the electric field to be measured, wherein the electric field sensitive structure includes any one of the following: a charge induction structure, an electrostatic force structure, a piezoelectric structure, a piezoresistive structure and a guided charge structure; a field enhancement cover plate, the field enhancement cover plate is located above the electric field sensitive structure, and is used to concentrate the electric field to be measured so as to enhance the electric field strength acting on the electric field sensitive structure; an insulating support structure layer, arranged at the edge of the substrate, and is used to connect the field enhancement cover plate and the substrate.

[0035] The following will be passed Figure 1 to Figure 6 The wafer-level enhanced electric field sensor of the disclosed embodiment is described in detail.

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

[0037] According to an embodiment of the present disclosure, a substrate is used to support an electric field sensitive structure, and anchor points are arranged on the surface of the substrate.

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

[0039] According to an embodiment of the present disclosure, the edge of the upper surface of the substrate, that is, the periphery of the upper surface of the substrate is a bonding area, and the insulating support structure layer is bonded to the bonding area of ​​the substrate.

[0040] According to an embodiment of the present disclosure, an electric field sensitive structure is disposed on a substrate and is used to sense an electric field to be measured.

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

[0042] According to an embodiment of the present disclosure, the field enhancement cover plate is located above the electric field sensitive structure, and is used to concentrate 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, the insulating support structure layer is disposed at the edge of the substrate and is used to connect 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 contacts the lower surface of the field enhancement cover plate, the lower surface of the insulating support structure layer contacts the substrate, and the insulating support structure layer is connected to the substrate by bonding.

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

[0046] According to an embodiment of the present disclosure, the insulating support structure layer may be composed of one or more insulating materials, or may be composed of a composite material. When the insulating support structure layer is composed of a composite material, the outermost layer material of the composite material is an insulating material.

[0047] According to the embodiments of the present disclosure, a wafer-level enhanced electric field sensor includes a substrate, an electric field sensitive structure, a field enhanced cover plate and an insulating support structure layer, wherein the electric field sensitive structure is arranged on the substrate, the lower surface of the insulating support structure layer is bonded to the substrate in a bonding area, and the upper surface of the insulating support structure layer is connected to the field enhanced cover plate, so that the field enhanced 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 enhanced cover plate and the substrate can be maintained. The field enhanced cover plate first concentrates the electric field to be measured, and the electric potential of the electric field to be measured after passing through the field enhanced cover plate increases, and the electric field strength increases, thereby achieving enhancement of the electric field strength of the electric field to be measured acting on the electric field sensitive structure, thereby improving the sensitivity of the electric field sensor. In addition, the wafer-level enhanced electric field sensor has a simple structure and is easy to prepare, thereby achieving wafer-level packaging of the electric field sensor, further improving the concentration effect of the electric field to be measured, and improving the sensitivity of the electric field sensor.

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

[0049] like Figure 1 As shown, Figure 1 The structure of a wafer-level enhanced electric field sensor is shown. The wafer-level enhanced electric field sensor includes a substrate 101, an electric field sensitive structure 102, a field enhanced 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 enhanced cover plate 103, and the lower surface of the insulating support structure layer 104 is bonded to the bonding area of ​​the substrate 101. The electric field sensitive structure 102 is bonded to the substrate 101. The electric field to be measured passes through the field enhanced cover plate 103 to increase the electric field strength, thereby further improving the sensitivity of the wafer-level enhanced electric field sensor.

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

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

[0052] like Figure 2As shown, taking the electric field sensitive structure as a charge induction structure as an example, the electric field sensitive structure includes a shielding electrode 201, a sensing electrode 202, a driving electrode 203, an elastic beam 204 and an anchor point 205, wherein the sensing electrode 202 is connected to the substrate through the anchor point 205, two groups of sensing electrodes 202 are distributed in the middle of the shielding electrode 201, one group of sensing electrodes 202 is distributed on the front side of the shielding electrode 201, and the other group of sensing electrodes 202 is distributed on the rear side of the shielding electrode 201, the sensing electrodes 202 are covered with comb teeth, the comb teeth on the sensing electrodes 202 are staggered with the comb teeth on the shielding electrode 201, and the shielding electrode 201 and the sensing electrodes 202 are staggered. The shielding electrode 201 is coplanar with the sensing electrode 202. The left and right sides of the shielding electrode 201 are connected with elastic beams 204, the elastic beams 204 are connected to the anchor point 205, and the elastic beams 204 are connected to the substrate through the anchor point 205. The left, right and middle parts of the shielding electrode 201 are all covered with comb teeth. There are four groups of driving electrodes 203, and each group of driving electrodes is covered with comb teeth. The comb teeth in the middle of the shielding electrode 201 are staggered with the comb teeth of the sensing electrode 202, and the comb teeth on the left and right sides of the shielding electrode 201 are staggered with the comb teeth of the driving electrode 203. The driving electrode 203 can be one of electrostatic drive, piezoelectric drive, thermal drive or a combination thereof, which is not limited here.

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

[0054] According to an embodiment of the present disclosure, the upper surface of the cover plate is perpendicular to the electric field to be measured, which is equivalent to the upper surface of the cover plate facing the electric field to be measured, and the lower surface of the cover plate contacts the insulating support structure layer to increase the electric field strength.

[0055] According to an embodiment of the present disclosure, the reinforcement structure is located directly above the electric field sensitive structure, and the reinforcement structure is located on the upper surface of the cover plate and / or the lower surface of the cover plate, and is used to concentrate the electric field to be measured.

[0056] According to an embodiment 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; another is that there is only one enhancement structure, and the enhancement structure is located on the upper surface of the cover plate; and another 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 embodiments of the present disclosure, since the field enhancement cover plate includes a cover plate and a reinforcement structure, the upper surface of the cover plate is perpendicular to the electric field to be measured to facilitate the electric field to be measured to enter the cover plate, and the lower surface of the cover plate is connected to the insulating support structure layer. The reinforcement structure can be located on the upper surface of the cover plate or on the lower surface of the cover plate. When it is necessary to test the electric field to be measured, the electric field to be measured passes through the cover plate and the reinforcement structure, thereby concentrating the electric field to be measured, increasing the electric potential of the electric field to be measured, increasing the electric field strength of the electric field to be measured received by the electric field sensitive structure, and improving the sensitivity of the wafer-level enhanced electric field sensor.

[0058] According to an embodiment of the present disclosure, a middle layer insulating region may be included between the cover plate and the reinforcement structure.

[0059] According to an embodiment of the present disclosure, the middle insulating region is made of a high dielectric constant material, which is used to increase the capacitance between the cover plate and the reinforcement structure, so as to increase the electrical potential of the structure below the middle insulating region.

[0060] According to an embodiment of the present disclosure, when the reinforcement 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 to increase the electric potential of the lower surface of the cover plate. The middle-layer insulating area is a high dielectric constant material, which is used to increase the capacitance between the cover plate and the reinforcement structure so as to increase the electric potential of the reinforcement structure. The reinforcement structure is then attached to the lower surface of the middle-layer insulating area to reduce the distance between the reinforcement structure and the electric field sensitive structure so as to increase the electric field strength.

[0061] According to an embodiment of the present disclosure, the field enhancement cover plate may further include a conductor column, which is located in the middle insulating region and is used to connect the cover plate and the enhancement structure to further improve the electric field strength.

[0062] According to an embodiment of the present disclosure, the cover plate may also be directly connected to the reinforcement structure, and may also be used to concentrate the electric field to be measured so as to improve the electric field strength.

[0063] According to an embodiment of the present disclosure, when the middle insulating area is located between the cover plate and the reinforcement structure, since the cover plate has a certain thickness, the voltage on the lower surface of the cover plate can be the potential of the electric field to be measured at the centroid coordinates of the cover plate, so that compared with a plane without thickness, the potential of the lower surface of the cover plate increases, and the voltage on the lower surface of the cover plate is consistent with the voltage on the upper surface of the middle insulating area, so that the potential on the upper surface of the middle insulating area is also increased. The middle insulating area is composed of a high dielectric constant material, and the capacitance between the cover plate and the reinforcement structure is increased through the middle insulating area to increase the potential of the electric field to be measured on the lower surface of the middle insulating area and the reinforcement structure, thereby increasing the electric field strength of the electric field to be measured received by the electric field sensitive structure, thereby improving the sensitivity of the electric field sensor.

[0064] According to the embodiments of the present disclosure, even if the cover plate is directly connected to the reinforcement structure, since the cover plate has a certain thickness, the voltage on the lower surface of the cover plate can be the potential of the electric field to be measured at the centroid coordinates of the cover plate. Therefore, compared with a plane without thickness, the potential of the lower surface of the cover plate is increased, and the voltage on the lower surface of the cover plate is consistent with the voltage on the upper surface of the reinforcement structure. The reinforcement structure also has a certain thickness, thereby also increasing the potential of the electric field to be measured of the reinforcement structure, thereby increasing the electric field strength of the electric field to be measured received by the electric field sensitive structure, and improving the sensitivity of the electric field sensor.

[0065] According to an embodiment of the present disclosure, when the reinforcement 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 to increase the electric potential of the lower surface of the cover plate. The middle-layer insulating area is a high dielectric constant material, which is used to increase the capacitance between the cover plate and the reinforcement structure so as to increase the electric potential of the reinforcement structure. The reinforcement structure is then attached to the lower surface of the middle-layer insulating area to reduce the distance between the reinforcement structure and the electric field sensitive structure so as to increase the electric field strength.

[0066] According to the embodiments of the present disclosure, when the enhancement structure is located on the lower surface of the cover plate, the overall structural shape of the field enhancement cover plate is "T"-shaped. After the electric field to be measured is applied to the field enhancement cover plate, the electric potential on the surface of the cover plate is the same. Since the enhancement structure is at a shorter distance from the electric field sensitive structure, according to the principle that the smaller the distance between the two plates is, the greater the field strength between the plates is under the same potential difference, the electric field strength of the electric field to be measured on the lower surface of the enhancement structure is enhanced, thereby increasing the electric field strength of the electric field to be measured received by the electric field sensitive structure, thereby improving the sensitivity of the electric field sensor.

[0067] According to an embodiment of the present disclosure, when the enhancement structure is located on the upper surface of the cover plate, since the field enhancement cover plate is in a convex shape, the electric field distribution inside the conductor is related to the shape of the conductor surface, thereby increasing the electric potential of the field enhancement cover plate and the electric field strength above the electric field sensitive structure.

[0068] According to an embodiment of the present disclosure, when there are two reinforcement structures in total, one reinforcement structure is located on the upper surface of the cover plate, and the other reinforcement structure is located on the lower surface of the cover plate, the reinforcement structure on the upper surface of the cover plate can increase the electric potential of the surface of the cover plate, and the reinforcement structure on the lower surface of the cover plate can reduce the distance between the reinforcement structure and the cover plate, thereby further significantly increasing the electric potential of the electric field to be measured, enhancing the electric field strength of the electric field to be measured, increasing the strength of the electric field to be measured received by the electric field sensitive structure, and improving the sensitivity of the electric field sensor.

[0069] According to an embodiment of the present disclosure, the shape of the reinforcement structure may be any one of a truncated cone, a prism, a truncated pyramid, a cylinder and a cone.

[0070] According to an embodiment of the present disclosure, the cover plate may be composed of a composite material whose outermost layer is a conductive layer. The cover plate may also be composed of one or more conductor materials, and the conductor material may include silicon and conductive metal.

[0071] According to the embodiments of the present disclosure, the reinforcement structure may be composed of a composite material whose outermost layer is a conductive layer. The reinforcement structure may also be composed of one or more layers of insulating material and conductive material. The reinforcement structure may also be composed of one or more layers of conductor material. The conductor material may include silicon and conductive metal. The insulating material may include glass, ceramic, and plastic.

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

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

[0074] like Figure 3 As shown, Figure 3 The structure of a field enhancement cover plate is shown in the case where the enhancement structure is located on the lower surface of the cover plate. The field enhancement cover plate includes a cover plate 301 and an enhancement structure 302. The cover plate 301 and the enhancement structure 302 are connected in a "T" shape. According to the principle that the smaller the distance between the two plates is, the greater the field strength between the plates is under the same potential difference, the electric field strength of the electric field to be measured on the lower surface of the enhancement structure is enhanced, thereby increasing the electric field strength of the electric field to be measured received by the electric field sensitive structure, thereby improving the sensitivity of the electric field sensor.

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

[0076] like Figure 4 As shown, Figure 4The specific structure of the field enhancement cover plate is shown in the case where the enhancement structure is located on the lower surface of the cover plate. The field enhancement cover plate includes a cover plate 401, a middle insulating region 402 and an enhancement structure 403. The upper surface of the middle insulating region 402 is attached to the lower surface of the cover plate 401, and the lower surface of the middle insulating region 402 is attached to the upper surface of the enhancement structure 403. The cover plate 401, the middle insulating region 402 and the enhancement structure 403 form a "sandwich" structure. Since the cover plate has a certain thickness, the voltage on the lower surface of the cover plate can be the voltage of the electric field to be measured on the cover plate. The electric potential at the centroid coordinates of the cover plate is increased compared to a plane without thickness. The voltage on the lower surface of the cover plate is consistent with the voltage on the upper surface of the middle insulating area, so that the electric potential on the upper surface of the middle insulating area is also increased. The middle insulating area is composed of a high dielectric constant material. The capacitance between the cover plate and the reinforcement structure is increased through the middle insulating area to increase the electric potential of the electric field to be measured on the lower surface of the middle insulating area and the reinforcement structure, thereby increasing the electric field strength of the electric field to be measured received by the electric field sensitive structure and improving the sensitivity of the electric field sensor.

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

[0078] like Figure 5 As shown, Figure 5 A field enhancement cover plate with a conductor column 504 is shown, which includes a cover plate 501, a middle insulating region 502, an enhancement structure 503 and a conductor column 504. The conductor column 504 is in the middle of the middle insulating region 502. The upper surface of the conductor column 504 is connected to the lower surface of the cover plate 501, and the lower surface of the conductor column 504 is connected to the upper surface of the enhancement structure 503, thereby further improving the electric potential of the enhancement structure 503 and improving the electric field strength of the electric field to be measured.

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

[0080] like Figure 6 As shown, Figure 6 A field enhancement cover plate is shown in which 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. The field enhancement cover plate includes a cover plate 601, a first enhancement structure 602 and a second enhancement structure 603. The first enhancement structure 602 can increase the electric potential on the surface of the cover plate 601, and the second enhancement structure 603 can reduce the distance between the field enhancement cover plate and the cover plate 601, thereby further significantly increasing the electric potential of the electric field to be measured, enhancing the electric field strength of the electric field to be measured, increasing the strength of the electric field to be measured received by the electric field sensitive structure, and improving the sensitivity of the electric field sensor.

[0081] Figure 7 The flowchart of the method for preparing the wafer-level enhanced electric field sensor according to the embodiment of the present disclosure is schematically shown.

[0082] like Figure 7 As shown, the method for preparing the wafer-level enhanced electric field sensor of this embodiment includes operations S710 to S760.

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

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

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

[0086] In operation S720, a glass medium is filled in the groove by using a glass reflow process, and redundant glass layers and silicon layers on the upper and lower sides 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 may be composed of a glass medium.

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

[0089] In operation S740, etching is performed on the device layer of the silicon-on-insulator by using a photolithography and 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 may be characterized as an SOI wafer, and the substrate may be composed of the SOI wafer.

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

[0092] In operation S750, a silicon oxide layer in the substrate connected to the sensitive structure is etched by a wet etching process to release the electric field sensitive structure in the substrate so that the electric field sensitive structure can vibrate freely.

[0093] According to an embodiment of the present disclosure, a wet etching process is used to etch the silicon oxide layer of the SOI device so that part of the electric field sensitive structure is not connected to the substrate, thereby releasing the electric field sensitive structure so that the electric field sensitive structure can vibrate freely and detect the electric field to be measured.

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

[0095] According to the embodiments of the present disclosure, an insulating support structure layer is provided on the cover plate, and then the cover plate is etched by 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 a photolithography etching process to obtain a substrate including an electric field sensitive structure, and then a silicon dioxide layer in the substrate including the electric field sensitive structure is removed by a wet etching process to release the electric field sensitive structure, and the substrate and the insulating support structure layer are bonded together to obtain a wafer-level enhanced electric field sensor, thereby realizing the preparation of the wafer-level enhanced electric field sensor. The sensor connects a field enhancement cover plate to the top of a silicon wafer through an insulating support structure layer, and then connects the circuit and the electric field sensitive structure to obtain an SOI wafer containing multiple electric field sensitive structures, and then performs a dicing operation to divide the SOI wafer containing multiple electric field sensitive structures to obtain SOI wafers each containing only one electric field sensitive structure, thereby realizing wafer-level packaging of electric field sensors. The wafer-level enhanced electric field sensor has a simple structure and is easy to prepare, and its concentrated effect on the electric field to be measured is enhanced, thereby significantly improving the sensitivity of the wafer-level enhanced electric field sensor.

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

[0097] like Figure 8 As shown, Figure 8The process of preparing a 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 shadow layer 802 represents the silicon dioxide layer. First, a groove is etched on the silicon wafer by a photolithography process to reserve the position of the insulating support structure layer (a). Then, a 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 an insulating support structure layer and connected to the silicon wafer (b). Then, the silicon wafer with the insulating support structure layer is etched by a photolithography process to obtain an enhanced structure, and the enhanced structure is etched by photolithography. A certain amount of thinning is performed to obtain a field enhancement cover plate with an insulating support structure layer (c). While preparing the field enhancement cover plate and the insulating support structure layers (a) to (c), an electric field sensitive structure is prepared on the substrate. The electric field sensitive structure is first etched on the SOI device layer on the SOI wafer by photolithography (d), and 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 to the insulating support structure layer is aligned and bonded to the substrate containing the electric field sensitive structure, and then diced to obtain a wafer-level enhanced electric field sensor.

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

[0099] According to an embodiment of the present disclosure, the electric field sensor may 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] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways without departing from the spirit and teachings of the present disclosure. All of these combinations and / or combinations 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 in detail. It should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A wafer-level enhanced electric field sensor, comprising: A substrate, used to support the electric field sensitive structure, wherein an anchor point is arranged on the surface of the substrate; An electric field sensitive structure, arranged on the substrate, for sensing the electric field to be measured, wherein the electric field sensitive structure includes any one of the following: a charge induction structure, an electrostatic force structure, a piezoelectric structure, a piezoresistive structure and a charge-guiding structure; A field enhancement cover plate, the field enhancement cover plate is located above the electric field sensitive structure and is used to concentrate the electric field to be measured so as to enhance the electric field strength acting on the electric field sensitive structure; An insulating support structure layer is arranged at the edge of the substrate and is used to connect the field enhancement cover plate and the substrate.

2. The sensor according to claim 1, characterized in that The field enhancement cover plate comprises a cover plate and an enhancement structure; The upper surface of the cover plate is perpendicular to the electric field to be measured, and the lower surface of the cover plate is in contact with the insulating support structure layer, so as to increase the electric field strength; The reinforcement structure is located directly above the electric field sensitive structure. The reinforcement structure is located on the upper surface of the cover plate and / or the lower surface of the cover plate, and is used to concentrate the electric field to be measured.

3. The sensor according to claim 2, characterized in that A middle insulating region is included between the cover plate and the reinforcement structure. The middle insulating region is made of a high dielectric constant material and is used to increase the capacitance between the cover plate and the reinforcement structure so as to increase the electrical potential of the structure below the middle insulating region.

4. The sensor according to claim 2, characterized in that The field enhancement cover plate further comprises a conductor column, which is located in the middle insulating region and is used to connect the cover plate and the enhancement structure.

5. The sensor according to claim 2, characterized in that Also includes: The cover plate is directly connected to the reinforcement structure and is used to concentrate the electric field to be measured so as to improve the electric field strength.

6. The sensor according to claim 2, characterized in that The shape of the reinforcement structure includes any one of the following: truncated cone, prism, prism, cylinder, cone.

7. The sensor according to claim 2, characterized in that The cover plate is composed of a composite material with the outermost layer being a conductive layer, or is composed of one or more conductive materials; The reinforcement structure is composed of a composite material whose outermost layer is a conductive layer, or is composed of one or more layers of conductive material; The insulating support structure layer is composed of one or more insulating materials, or is composed of a composite material whose outermost layer is an insulating material.

8. A method for preparing a wafer-level enhanced electric field sensor, comprising: Etching a groove on a silicon wafer using a photolithography process to obtain a cover plate containing a groove, wherein the groove represents a position of an insulating support structure layer reserved on the cover plate; Filling the groove with glass medium by glass reflow process, and removing the upper and lower redundant glass layers and silicon layers by grinding and polishing to obtain an insulating support structure layer connected to the cover plate; Etching the cover plate by a photolithography process to obtain an enhanced structure, and thinning the enhanced structure by photolithography to obtain a field enhancement structure connected to the insulating support structure layer; Etching the device layer of silicon on insulator by photolithography and etching process to obtain a substrate connected with an electric field sensitive structure; Etching the silicon oxide layer in the substrate connected with the sensitive structure by 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; The insulating support structure layer is aligned with the substrate and then subjected to bonding and dicing operations to obtain the wafer-level enhanced electric field sensor.

9. An electric field sensor, comprising: The wafer-level field-enhanced electric field sensor according to any one of claims 1 to 7 or the wafer-level field-enhanced electric field sensor obtained by the preparation method according to claim 8.

10. The electric field sensor according to claim 9, characterized in that: The electric field sensor also includes a two-dimensional or three-dimensional electric field sensor composed of a plurality of electric field sensitive structures, which is used to measure a two-dimensional or three-dimensional electric field or voltage.

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