CN118362774B - Single chip integrated current sensor and manufacturing method - Google Patents
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Abstract
The invention relates to the field of electronic sensors, and provides a single-chip integrated current sensor and a manufacturing method thereof. The single chip integrated current sensor includes: the electromagnetic induction energy-taking unit generates induction current based on an electromagnetic induction principle, and the wireless communication unit adopts a dipole antenna technology to send and receive signals; the current measuring unit, the electromagnetic induction energy taking unit and the wireless communication unit are integrated on a single chip. The integrated current sensor can integrate the functional structures such as current detection, energy taking and communication on a single chip by utilizing the micro-electromechanical system processing technology, can realize batch production, has low production cost, small volume and light weight, and is beneficial to large-scale arrangement on long-distance transmission lines.
Description
Technical Field
The invention relates to the field of electronic sensors, in particular to a single-chip integrated current sensor and a manufacturing method thereof.
Background
Detection/monitoring of power line conductor current in power systems is very important, and current sensors are typically employed to detect current. Because the power line is basically an unattended environment, the long-term power supply and the reliable data communication of the power line current sensor are urgent to solve. By utilizing the characteristic that the power transmission line has alternating current, namely the characteristic that alternating current can generate alternating magnetic field, electromagnetic induction energy taking (CT energy taking) has been widely applied to the power transmission line.
In the prior art, a current sensor module, a CT energy taking module and a communication module are assembled, and detection, energy taking and communication are integrated into one device or product, but the assembled structure cannot be produced in an integrated and batch mode, so that the assembly structure is high in production cost and is not beneficial to large-scale arrangement on a long-distance transmission line; moreover, the assembled structure has larger volume and heavier weight, and the lead is easy to be overweight when being mounted on the power transmission line, so that the power transmission line is easy to be broken down under the action of external force (such as strong wind and the like).
Disclosure of Invention
In order to solve the technical problems, the invention provides a single-chip integrated current sensor and a manufacturing method thereof, wherein the single-chip integrated current sensor integrates functional structures such as current detection, energy taking and communication and the like on a single chip, and can detect current, electromagnetic induction energy taking and radio frequency antenna communication simultaneously.
One aspect of the present invention provides a single chip integrated current sensor comprising: the device comprises a current measuring unit, an electromagnetic induction energy taking unit and a wireless communication unit;
The current measurement unit is used for detecting the current to be measured based on a fluxgate technology;
the electromagnetic induction energy-taking unit is used for generating induction current based on an electromagnetic induction principle;
the wireless communication unit adopts a dipole antenna technology to transmit and receive signals;
The current measuring unit, the electromagnetic induction energy taking unit and the wireless communication unit are integrated on a single chip.
In the embodiment of the invention, the electromagnetic induction energy-taking unit is connected with the current measuring unit and/or the wireless communication unit and is used for providing the current measuring unit and/or the wireless communication unit with required electric energy.
In the embodiment of the invention, the electromagnetic induction energy-taking unit is connected with a rechargeable battery or a super capacitor, and the induction current generated by the electromagnetic induction energy-taking unit is stored through the rechargeable battery or the super capacitor.
In an embodiment of the present invention, the current measurement unit includes: the magnetic core, the fluxgate excitation coil and the fluxgate induction coil are wound on the magnetic core.
In an embodiment of the present invention, the electromagnetic induction energy capturing unit includes: the magnetic core and electromagnetic induction coil, electromagnetic induction coil twines on the magnetic core.
In the embodiment of the invention, the magnetic core, the fluxgate excitation coil and the fluxgate induction coil of the current measuring unit, and the magnetic core and the electromagnetic induction coil of the electromagnetic induction energy-taking unit are formed on the same semiconductor substrate through a micro-electromechanical processing technology.
In the embodiment of the invention, the magnetic core of the current measuring unit and the magnetic core of the electromagnetic induction energy taking unit are the same magnetic core.
In the embodiment of the invention, the fluxgate excitation coil and the fluxgate induction coil of the current measuring unit are wound at one end of the magnetic core, and the electromagnetic induction coil of the electromagnetic induction energy taking unit is wound at the other end of the magnetic core.
In the embodiment of the invention, the fluxgate excitation coil comprises two groups of excitation coils which are respectively positioned at two sides of the fluxgate induction coil; the two groups of exciting coils are connected in a reverse way.
In the embodiment of the invention, the fluxgate induction coils comprise a plurality of groups of induction coils, and the connection modes of the groups of induction coils are in same-direction connection.
In the embodiment of the invention, the wireless communication unit comprises a planar antenna and an antenna element.
In the embodiment of the invention, the planar antenna is a planar spiral antenna.
In the embodiment of the invention, the planar spiral antenna, the fluxgate excitation coil, the fluxgate induction coil and the electromagnetic induction coil are formed simultaneously in the same process step.
In the embodiment of the invention, the planar spiral antenna, the fluxgate excitation coil, the fluxgate induction coil and the electromagnetic induction coil are formed on the same plane of the semiconductor substrate.
In the embodiment of the invention, the planar spiral antenna, the fluxgate excitation coil, the fluxgate induction coil and the electromagnetic induction coil are formed by adopting an electroplating process or a liquid metal casting process.
In the embodiment of the invention, the planar spiral antenna is an equiangular spiral antenna or an archimedes spiral antenna.
In the embodiment of the invention, the antenna element is in a butterfly shape, a rod shape, a plate shape or a sheet shape.
In an embodiment of the present invention, the current measurement unit further includes a closed loop feedback coil of the fluxgate, and the closed loop feedback coil of the fluxgate is wound on the magnetic core.
In the embodiment of the invention, the magnetic core is of a thick film structure formed by processing soft magnetic materials.
In the embodiment of the invention, the magnetic core is of a film structure formed by an electroplating process.
In the embodiment of the invention, the magnetic core is rectangular, triangular, annular or racetrack.
In the embodiment of the invention, the fluxgate exciting coil, the fluxgate induction coil and the electromagnetic induction coil are of a solenoid coil structure.
The invention further provides a manufacturing method of the single-chip integrated current sensor, the single-chip integrated current sensor comprises a current measuring unit, an electromagnetic induction energy taking unit and a wireless communication unit, the current measuring unit comprises a magnetic core, a fluxgate excitation coil and a fluxgate induction coil, the electromagnetic induction energy taking unit comprises the magnetic core and the electromagnetic induction coil, and the wireless communication unit comprises a planar antenna;
The manufacturing method of the single-chip integrated current sensor comprises the following steps:
forming a bottom metal coil and a planar spiral metal coil serving as a planar antenna on a semiconductor wafer;
manufacturing a magnetic core on the bottom metal coil;
And forming a top metal coil on the surface of the magnetic core, so that the bottom metal coil and the top metal coil form a fluxgate excitation coil, a fluxgate induction coil and an electromagnetic induction coil which are wound on the magnetic core.
In an embodiment of the present invention, forming a bottom metal coil and a planar spiral metal coil as a planar antenna on a semiconductor wafer includes:
Depositing an insulating layer on the surface of the semiconductor wafer;
sputtering metal on the surface of the insulating layer to form a seed layer;
electroplating metal on the surface of the seed layer to form a bottom metal coil and a planar spiral metal coil.
In the embodiment of the invention, the magnetic core is manufactured on the bottom metal coil, and the method comprises the following steps: the method comprises the steps of electroplating magnetic materials on a bottom metal coil to form a magnetic core, or placing a prefabricated magnetic core on the bottom metal coil, wherein the prefabricated magnetic core is a thick film magnetic core formed by processing soft magnetic materials.
In the embodiment of the invention, a top metal coil is formed on the surface of a magnetic core, and the method comprises the following steps: and electroplating metal on the surface of the magnetic core to form a top metal coil, and removing the residual seed layer.
In another embodiment of the present invention, forming a bottom metal coil on a semiconductor wafer includes:
etching a groove on a semiconductor wafer;
depositing an insulating layer in the groove;
and casting liquid metal or alloy material in the groove with the insulating layer to form the bottom metal coil.
In another embodiment of the present invention, a magnetic core is fabricated on an underlying metal coil, comprising: and placing a prefabricated magnetic core in the groove with the bottom metal coil, wherein the prefabricated magnetic core is a thick film magnetic core formed by processing soft magnetic materials.
In another embodiment of the present invention, forming a top metal coil on a surface of a magnetic core includes:
bonding the semiconductor wafer with the magnetic core;
And etching a casting groove of the top metal coil on the semiconductor wafer, and casting liquid metal or alloy material to form the bottom metal coil.
According to the single-chip integrated current sensor provided by the invention, the current measuring unit, the electromagnetic induction energy obtaining unit and the wireless communication unit are integrated on a single chip, the electromagnetic induction energy obtaining unit obtains the induction current from the power line, and meanwhile, the current measuring unit and the wireless communication unit are powered, so that the power supply and communication problems in the current detection process are solved. The integrated current sensor can integrate functional structures such as current detection, energy taking and communication on a single chip by utilizing a Micro-Electro-MECHANICAL SYSTEM (MEMS) processing technology, can be produced in batch, has low production cost, small volume and light weight, and is beneficial to large-scale arrangement on long-distance transmission lines.
Other features and advantages of the present invention will be apparent from the detailed description that follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and do not constitute a limitation on the invention. In the drawings:
fig. 1 is a schematic structural diagram of a single-chip integrated current sensor according to an embodiment of the present invention;
Fig. 2 is a schematic structural diagram of a single-chip integrated current sensor according to a second embodiment of the present invention;
Fig. 3 is a schematic structural diagram of a single-chip integrated current sensor according to a third embodiment of the present invention;
fig. 4 is a flowchart of a method for manufacturing a single-chip integrated current sensor according to an embodiment of the present invention.
Description of the reference numerals
100-Current measuring unit, 200-electromagnetic induction energy-taking unit, 300-wireless communication unit,
101-First core, 102-fluxgate excitation coil, 103-fluxgate induction coil,
104-Fluxgate excitation coil PAD, 105-fluxgate induction coil PAD,
106-Fluxgate closed loop feedback coil, 107-fluxgate closed loop feedback coil PAD,
201-A second magnetic core, 202-an electromagnetic coil, 203-an electromagnetic coil PAD,
301-Planar antenna, 302-antenna element, 303-antenna feed point.
Detailed Description
In order to make the technical solutions and advantages of the embodiments of the present invention more apparent, the following detailed description of exemplary embodiments of the present invention is provided in conjunction with the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention and not exhaustive of all embodiments. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element in question must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise. The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature.
In the present invention, unless explicitly specified and limited otherwise, terms such as "mounted," "connected," "secured," and the like are to be construed broadly and may be, for example, fixedly attached, detachably attached, or integrally formed; may be mechanically connected, may be electrically connected or may communicate with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The embodiment of the invention provides a single-chip integrated current sensor which comprises a current measuring unit, an electromagnetic induction energy taking unit and a wireless communication unit. The current measuring unit is used for detecting the current to be measured based on a fluxgate technology; the electromagnetic induction energy-taking unit is used for generating induction current based on an electromagnetic induction principle; the wireless communication unit transmits and receives signals using dipole antenna technology. The current measuring unit, the electromagnetic induction energy taking unit and the wireless communication unit are integrated on a single chip. The electromagnetic induction energy-taking unit is connected with the current measuring unit and the wireless communication unit, and simultaneously provides the current measuring unit and the wireless communication unit with required electric energy. Or the electromagnetic induction energy-taking unit is connected with the current measuring unit to provide the current measuring unit with the required electric energy; or the electromagnetic induction energy-taking unit is connected with the wireless communication unit to provide the wireless communication unit with the required electric energy. The electromagnetic induction energy-taking unit can be connected with a rechargeable battery or a super capacitor, the induction current generated by the electromagnetic induction energy-taking unit is stored through the rechargeable battery or the super capacitor, and the current measuring unit and/or the wireless communication unit are powered through the rechargeable battery or the super capacitor.
According to the single-chip integrated current sensor provided by the invention, the current measuring unit, the electromagnetic induction energy obtaining unit and the wireless communication unit are integrated on a single chip, the electromagnetic induction energy obtaining unit obtains the induction current from the power line, and meanwhile, the current measuring unit and the wireless communication unit are powered, so that the power supply and communication problems in the current detection process are solved. The integrated current sensor can integrate the functional structures such as current detection, energy taking and communication on a single chip by utilizing the MEMS processing technology, can be produced in batch, has low production cost, small volume and light weight, and is beneficial to large-scale arrangement on long-distance transmission lines.
Example 1
Fig. 1 is a schematic structural diagram of a single-chip integrated current sensor according to an embodiment of the invention. As shown in fig. 1, the single-chip integrated current sensor provided in this embodiment includes a current measurement unit 100, an electromagnetic induction energy-taking unit 200, and a wireless communication unit 300. The current measurement unit 100 includes a first magnetic core 101, a fluxgate excitation coil 102, and a fluxgate induction coil 103, and the fluxgate excitation coil 102 and the fluxgate induction coil 103 are wound on the first magnetic core 101. Fluxgate excitation coil 102 is connected to fluxgate excitation coil PAD (PAD pin) 104, and fluxgate induction coil 103 is connected to fluxgate induction coil PAD105. The electromagnetic induction energy taking unit 200 includes a magnetic core and an electromagnetic induction coil 202, the electromagnetic induction coil 202 is wound on the magnetic core, and the electromagnetic induction coil 202 is connected to an electromagnetic induction coil PAD203. The magnetic core of the current measuring unit 100, the fluxgate excitation coil 102 and the fluxgate induction coil 103, and the magnetic core of the electromagnetic induction energy taking unit 200 and the electromagnetic induction coil 202 are formed on the same semiconductor substrate by a micro electromechanical process.
In this embodiment, the magnetic core of the current measurement unit 100 and the magnetic core of the electromagnetic induction energy taking unit 200 are the same magnetic core, the fluxgate exciting coil 102 and the fluxgate induction coil 103 of the current measurement unit 100 are wound at one end of the magnetic core, and the electromagnetic induction coil 202 of the electromagnetic induction energy taking unit 200 is wound at the other end of the magnetic core, that is, the current measurement unit 100 and the electromagnetic induction energy taking unit 200 share one magnetic core (that is, the first magnetic core 101).
The current measurement unit 100 measures a weak magnetic field based on a fluxgate technology by using a nonlinear relationship between the magnetic induction intensity and the magnetic field intensity of a high-permeability magnetic core in a measured magnetic field under the saturation excitation of an alternating magnetic field, thereby realizing current measurement. In this embodiment, the excitation magnetic field generated by the fluxgate excitation coil 102 of the current measurement unit 100 magnetically modulates the magnetic core material, drives the magnetic core material into a critical saturation state, and realizes high-sensitivity detection of the external magnetic field and the current to be measured by using the nonlinear variation characteristic of the magnetic permeability when the magnetic core is magnetized and saturated. As shown in fig. 1, the fluxgate excitation coil 102 of the current measurement unit 100 includes two groups of excitation coils respectively located at two sides of the fluxgate induction coil 103, and the two groups of excitation coils are connected in a reverse connection manner, so as to implement differential cancellation of induction signals generated by a transformer effect. The fluxgate induction coil 103 comprises a plurality of groups of induction coils, and the connection modes of the plurality of groups of induction coils are in same-direction connection, so that superposition enhancement of induction signals generated by a magnetic field to be detected is realized. The fluxgate induction coil 103 may be a single-group coil.
The electromagnetic induction energy-taking unit is based on an electromagnetic induction principle, when alternating current or an alternating magnetic field exists, the electromagnetic induction coil generates induction current at two ends of the induction coil due to the electromagnetic induction principle, and the electromagnetic induction electric energy can directly supply power to the current measuring unit or the wireless communication unit, can also be processed through the rear end, is connected with a rechargeable battery or a super capacitor to charge the rechargeable battery or the super capacitor, and stores the induction electric energy. The electromagnetic induction coil is a solenoid coil wound around a magnetic core. In order to reduce the chip area, the electromagnetic induction coil of the electromagnetic induction energy-taking unit, the fluxgate exciting coil of the current measuring unit and the fluxgate induction coil can share one magnetic core, or can not share one magnetic core, and are respectively wound on different magnetic core structures.
The main body of the wireless communication unit 300 is an antenna structure, and adopts a dipole antenna technology, including a planar antenna 301 and an antenna element 302, the planar antenna 301 being connected to an antenna feed point 303. The planar antenna is a planar helical antenna, which may be an equiangular helical antenna or an archimedes helical antenna in shape. The antenna element may be butterfly, rod, plate or sheet. The helical antenna is made of metal with good conductivity and has the advantages of circular polarization and wide beam width, and the planar helical antenna is generally added with a back cavity at the back to improve gain. The spiral antenna adopts a planar rectangular spiral structure preferentially, so that the production and the manufacturing are convenient, and the size and the weight of the antenna can be effectively reduced. In order to increase the bandwidth, the planar rectangular helical antenna terminal adopts a butterfly oscillator loading mode so as to reduce the transmission loss of the periphery of the helical line. The butterfly antenna is a broadband antenna, and adopts a loading mode of the broadband butterfly antenna, so that impedance matching of a broadband can be realized, and transmission loss can be reduced, thereby improving the radiation characteristic of the antenna. In addition, the butterfly antenna has the advantages of light weight, convenient installation and the like as an antenna with a low-profile plane structure.
In this embodiment, the planar spiral antenna of the wireless communication unit and the fluxgate excitation coil, the fluxgate induction coil and the electromagnetic induction coil can be formed simultaneously in the same process step. Further, the planar spiral antenna may be formed on the same plane as the fluxgate excitation coil, the fluxgate induction coil, and the electromagnetic induction coil. In terms of manufacturing processes, the planar spiral antenna, fluxgate excitation coil, fluxgate induction coil, and electromagnetic induction coil may be formed using an electroplating process or a liquid metal casting process.
In this embodiment, the fluxgate exciting coil, the fluxgate induction coil and the electromagnetic induction coil are of a solenoid coil structure, and the solenoid coil can be uniformly wound on the magnetic core. The magnetic core may be a thick film structure formed by processing a soft magnetic material or a thin film structure formed by using an electroplating process. The shape of the magnetic core may be any of rectangular, triangular, annular, or racetrack shape.
Example two
Fig. 2 is a schematic structural diagram of a single-chip integrated current sensor according to an embodiment of the invention. As shown in fig. 2, the single-chip integrated current sensor provided in this embodiment includes a current measurement unit 100, an electromagnetic induction energy-taking unit 200, and a wireless communication unit 300. The current measurement unit 100 includes a first magnetic core 101, a fluxgate excitation coil 102, and a fluxgate induction coil 103, and the fluxgate excitation coil 102 and the fluxgate induction coil 103 are wound on the first magnetic core 101. Fluxgate excitation coil 102 is connected to fluxgate excitation coil PAD104, and fluxgate induction coil 103 is connected to fluxgate induction coil PAD105. The electromagnetic induction energy taking unit 200 includes a second magnetic core 201 and an electromagnetic induction coil 202, the electromagnetic induction coil 202 is wound on the magnetic core, and the electromagnetic induction coil 202 is connected to an electromagnetic induction coil PAD203. The magnetic core of the current measuring unit 100, the fluxgate excitation coil 102 and the fluxgate induction coil 103, and the magnetic core of the electromagnetic induction energy taking unit 200 and the electromagnetic induction coil 202 are formed on the same semiconductor substrate by a micro electromechanical process.
In this embodiment, the current measurement unit 100 and the electromagnetic induction energy-obtaining unit 200 have respective magnetic core structures. The magnetic core of the current measurement unit 100 is a first magnetic core 101, the magnetic core of the electromagnetic induction energy taking unit 200 is a second magnetic core 201, the fluxgate excitation coil 102 and the fluxgate induction coil 103 of the current measurement unit 100 are wound on the first magnetic core 101, and the electromagnetic induction coil 202 of the electromagnetic induction energy taking unit 200 is wound on the second magnetic core 201.
In this embodiment, the fluxgate excitation coil 102 of the current measurement unit 100 includes two groups of excitation coils respectively located at two sides of the fluxgate induction coil 103, and the two groups of excitation coils are connected in a reverse connection manner, so as to implement differential cancellation of the induction signals generated by the transformer effect. The current measurement unit 100 further comprises a fluxgate closed loop feedback coil 106, the fluxgate closed loop feedback coil 106 being wound on the first magnetic core 101, the fluxgate closed loop feedback coil 106 being connected to a fluxgate closed loop feedback coil PAD107. The fluxgate induction coil 103 comprises one or more induction coils wound on the first magnetic core 101 for inducing a magnetic field to be measured to generate an induction signal. By processing the induction signal of the fluxgate induction coil 103 and the feedback signal of the fluxgate closed loop feedback coil 106, the measurement accuracy of the fluxgate can be improved.
The main body of the wireless communication unit 300 is an antenna structure, and adopts a dipole antenna technology, including a planar antenna 301 and an antenna element 302, the planar antenna 301 being connected to an antenna feed point 303. The planar antenna is a planar helical antenna, which may be an equiangular helical antenna or an archimedes helical antenna in shape. The antenna element may be butterfly, rod, plate or sheet. The helical antenna is made of metal with good conductivity and has the advantages of circular polarization and wide beam width, and the planar helical antenna is generally added with a back cavity at the back to improve gain. The spiral antenna adopts a planar rectangular spiral structure preferentially, so that the production and the manufacturing are convenient, and the size and the weight of the antenna can be effectively reduced. In order to increase the bandwidth, the planar rectangular helical antenna terminal adopts a butterfly oscillator loading mode so as to reduce the transmission loss of the periphery of the helical line. The butterfly antenna is a broadband antenna, and adopts a loading mode of the broadband butterfly antenna, so that impedance matching of a broadband can be realized, and transmission loss can be reduced, thereby improving the radiation characteristic of the antenna. In addition, the butterfly antenna has the advantages of light weight, convenient installation and the like as an antenna with a low-profile plane structure.
In this embodiment, the planar spiral antenna of the wireless communication unit, the fluxgate excitation coil, the fluxgate induction coil and the electromagnetic induction coil may be formed simultaneously in the same process step, and may be formed on the same plane of the semiconductor substrate by using an electroplating process or a liquid metal casting process. The magnetic cores of the current measuring unit and the electromagnetic induction energy taking unit can be thick film structures formed by processing soft magnetic materials or thin film structures formed by utilizing an electroplating process. The shape of the magnetic core may be any of rectangular, triangular, annular, or racetrack shape.
Example III
Fig. 3 is a schematic structural diagram of a single-chip integrated current sensor according to an embodiment of the invention. As shown in fig. 3, the single-chip integrated current sensor provided in this embodiment includes a current measurement unit 100, an electromagnetic induction energy-taking unit 200, and a wireless communication unit 300. The current measurement unit 100 includes a first magnetic core 101, a fluxgate excitation coil 102, and a fluxgate induction coil 103, and the fluxgate excitation coil 102 and the fluxgate induction coil 103 are wound on the first magnetic core 101. Fluxgate excitation coil 102 is connected to fluxgate excitation coil PAD (PAD pin) 104, and fluxgate induction coil 103 is connected to fluxgate induction coil PAD105. The electromagnetic induction energy taking unit 200 includes a magnetic core and an electromagnetic induction coil 202, the electromagnetic induction coil 202 is wound on the magnetic core, and the electromagnetic induction coil 202 is connected to an electromagnetic induction coil PAD203. The magnetic core of the current measuring unit 100, the fluxgate excitation coil 102 and the fluxgate induction coil 103, and the magnetic core of the electromagnetic induction energy taking unit 200 and the electromagnetic induction coil 202 are formed on the same semiconductor substrate by a micro electromechanical process.
In this embodiment, the magnetic core of the current measurement unit 100 and the magnetic core of the electromagnetic induction energy taking unit 200 are the same magnetic core, the fluxgate exciting coil 102 and the fluxgate induction coil 103 of the current measurement unit 100 are wound at one end of the magnetic core, and the electromagnetic induction coil 202 of the electromagnetic induction energy taking unit 200 is wound at the other end of the magnetic core, that is, the current measurement unit 100 and the electromagnetic induction energy taking unit 200 share one magnetic core (the first magnetic core 101).
In this embodiment, the fluxgate excitation coil 102 of the current measurement unit 100 includes two groups of excitation coils respectively located at two sides of the fluxgate induction coil 103, and the two groups of excitation coils are connected in a reverse connection manner, so as to implement differential cancellation of the induction signals generated by the transformer effect. The current measurement unit 100 further comprises a fluxgate closed loop feedback coil 106, the fluxgate closed loop feedback coil 106 being wound around one end of the magnetic core near the fluxgate induction coil 103, the fluxgate closed loop feedback coil 106 being connected to the fluxgate closed loop feedback coil PAD107. The fluxgate induction coil 103 comprises one or more induction coils wound on the first magnetic core 101 for inducing a magnetic field to be measured to generate an induction signal. By processing the induction signal of the fluxgate induction coil 103 and the feedback signal of the fluxgate closed loop feedback coil 106, the measurement accuracy of the fluxgate can be improved.
The main body of the wireless communication unit 300 is an antenna structure, and adopts a dipole antenna technology, including a planar antenna 301 and an antenna element 302, the planar antenna 301 being connected to an antenna feed point 303. The planar antenna is a planar helical antenna, which may be an equiangular helical antenna or an archimedes helical antenna in shape. The antenna element may be butterfly, rod, plate or sheet. The helical antenna is made of metal with good conductivity and has the advantages of circular polarization and wide beam width, and the planar helical antenna is generally added with a back cavity at the back to improve gain. The spiral antenna adopts a planar rectangular spiral structure preferentially, so that the production and the manufacturing are convenient, and the size and the weight of the antenna can be effectively reduced. In order to increase the bandwidth, the planar rectangular helical antenna terminal adopts a butterfly oscillator loading mode so as to reduce the transmission loss of the periphery of the helical line. The butterfly antenna is a broadband antenna, and adopts a loading mode of the broadband butterfly antenna, so that impedance matching of a broadband can be realized, and transmission loss can be reduced, thereby improving the radiation characteristic of the antenna. In addition, the butterfly antenna has the advantages of light weight, convenient installation and the like as an antenna with a low-profile plane structure.
In this embodiment, the planar spiral antenna of the wireless communication unit, the fluxgate excitation coil, the fluxgate induction coil and the electromagnetic induction coil may be formed simultaneously in the same process step, and may be formed on the same plane of the semiconductor substrate by using an electroplating process or a liquid metal casting process. The magnetic cores of the current measuring unit and the electromagnetic induction energy taking unit can be thick film structures formed by processing soft magnetic materials or thin film structures formed by utilizing an electroplating process. The shape of the magnetic core may be any of rectangular, triangular, annular, or racetrack shape.
The core idea of the single-chip integrated current sensor of the embodiment of the invention is that the single-chip integrated current measuring unit, the electromagnetic induction energy taking unit and the hardware main body of the wireless communication unit can realize the logic operation functions of current detection, energy taking and communication by a peripheral logic Circuit, and the peripheral logic Circuit can be independently realized in another PCB (Printcd Cicuils Board, printed Circuit board) or an ASIC (Application SPECIFIC INTEGRATED Circuit ). The PAD (fluxgate induction coil PAD, fluxgate closed loop feedback coil PAD, electromagnetic induction coil PAD) of each functional unit is connected with a PCB or an ASIC.
The embodiment of the invention also provides a manufacturing method of the single-chip integrated current sensor. As shown in fig. 4, the method for manufacturing a single-chip integrated current sensor provided in this embodiment includes the following steps:
S410, forming a bottom metal coil and a planar spiral metal coil serving as a planar antenna on a semiconductor wafer;
s420, manufacturing a magnetic core on the bottom metal coil;
s430, forming a top metal coil on the surface of the magnetic core, and enabling the bottom metal coil and the top metal coil to form a fluxgate excitation coil, a fluxgate induction coil and an electromagnetic induction coil which are wound on the magnetic core.
In one embodiment, in step S410, an insulating layer is deposited on the surface of the semiconductor wafer, and a seed layer is formed by sputtering metal on the surface of the insulating layer; electroplating metal on the surface of the seed layer to form a bottom metal coil and a planar spiral metal coil. In step S420, a magnetic thin film is formed as a magnetic core by electroplating a magnetic material on the bottom metal coil; or placing a prefabricated magnetic core on the bottom metal coil, wherein the prefabricated magnetic core is a thick film magnetic core formed by processing soft magnetic materials. In step S430, a top metal coil is formed by electroplating metal on the surface of the magnetic core, and the remaining seed layer is removed. Dicing the wafer to obtain individual sensing chips.
In another embodiment, in step S410, grooves are etched on a semiconductor wafer, an insulating layer is deposited in the grooves, and a liquid metal or alloy material is cast in the grooves with the insulating layer to form an underlying metal coil. In step S420, a preformed core, which is a thick film core formed by processing a soft magnetic material, is placed in the recess with the underlying metal coil. In step S430, a bonding process is performed on the semiconductor wafer with the magnetic core placed thereon, a casting groove of the top metal coil is etched on the semiconductor wafer, and a liquid metal or alloy material is cast to form the bottom metal coil.
For the single chip integrated current sensors of the second and third embodiments described above, the current measurement unit includes a fluxgate excitation coil, a fluxgate induction coil, and a fluxgate closed loop feedback coil. In step S410 of the above manufacturing method, the bottom metal coil serving as the closed-loop feedback coil of the fluxgate is formed simultaneously during the process of manufacturing the bottom metal coil on the semiconductor wafer, and in step S430, the top metal coil serving as the closed-loop feedback coil of the fluxgate is formed simultaneously during the process of manufacturing the top metal coil on the surface of the magnetic core.
The alternative embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the embodiments of the present invention are not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solutions of the embodiments of the present invention within the scope of the technical concept of the embodiments of the present invention, and all the simple modifications belong to the protection scope of the embodiments of the present invention. It should be noted that, in the case where the specific features described in the above-described specific embodiments are not contradictory, they may be combined in any suitable manner, as long as the combination does not deviate from the idea of the embodiment of the present invention, which should also be regarded as the disclosure of the embodiment of the present invention.
Claims (27)
1. A single chip integrated current sensor, comprising: the device comprises a current measuring unit, an electromagnetic induction energy taking unit and a wireless communication unit;
The current measurement unit is used for detecting the current to be measured based on a fluxgate technology;
the electromagnetic induction energy-taking unit is used for generating induction current based on an electromagnetic induction principle;
the wireless communication unit adopts a dipole antenna technology to transmit and receive signals;
The current measuring unit, the electromagnetic induction energy taking unit and the wireless communication unit are integrated on a single chip;
The current measurement unit includes: the magnetic core, the fluxgate excitation coil and the fluxgate induction coil are wound on the magnetic core;
The electromagnetic induction energy taking unit comprises: the electromagnetic induction coil is wound on the magnetic core;
The magnetic core, the fluxgate excitation coil and the fluxgate induction coil of the current measuring unit, the magnetic core and the electromagnetic induction coil of the electromagnetic induction energy-taking unit are formed on the same semiconductor substrate through a micro-electromechanical processing technology; the method of the micro-electromechanical processing technology comprises the following steps:
Forming a bottom metal coil on a semiconductor wafer;
Manufacturing a magnetic core on the bottom metal coil, wherein the magnetic core is used as a magnetic core of the current measuring unit and a magnetic core of the electromagnetic induction energy taking unit;
and forming a top metal coil on the surface of the magnetic core, so that the bottom metal coil and the top metal coil form a fluxgate excitation coil and a fluxgate induction coil of the current measuring unit and an electromagnetic induction coil of the electromagnetic induction energy taking unit.
2. The single chip integrated current sensor of claim 1, wherein the electromagnetic induction energy capturing unit is connected to the current measuring unit and/or the wireless communication unit for providing the current measuring unit and/or the wireless communication unit with the required electrical energy.
3. The single chip integrated current sensor of claim 1, wherein the electromagnetic induction energy capturing unit is connected to a battery or a super capacitor, and the induction current generated by the electromagnetic induction energy capturing unit is stored by the battery or the super capacitor.
4. The single chip integrated current sensor of claim 1, wherein the core of the current measurement unit is the same core as the core of the electromagnetic induction energy capturing unit.
5. The single chip integrated current sensor of claim 1, wherein the fluxgate excitation coil and the fluxgate induction coil of the current measuring unit are wound at one end of the magnetic core, and the electromagnetic induction coil of the electromagnetic induction energy taking unit is wound at the other end of the magnetic core.
6. The single chip integrated current sensor of claim 1 wherein the fluxgate excitation coil comprises two sets of excitation coils, one on each side of the fluxgate induction coil;
the two groups of exciting coils are connected in a reverse way.
7. The single chip integrated current sensor of claim 1 wherein the fluxgate induction coil comprises a plurality of groups of induction coils connected in a common direction.
8. The single chip integrated current sensor of claim 1, wherein the wireless communication unit comprises a planar antenna and an antenna element.
9. The single chip integrated current sensor of claim 8, wherein the planar antenna is a planar spiral antenna.
10. The single chip integrated current sensor of claim 9, wherein the planar spiral antenna is formed simultaneously with the fluxgate excitation coil, fluxgate induction coil, and electromagnetic induction coil in the same process step.
11. The single chip integrated current sensor of claim 10 wherein the planar spiral antenna is formed on the same plane as the fluxgate excitation coil, fluxgate induction coil, and electromagnetic induction coil.
12. The single chip integrated current sensor of claim 10 wherein the planar spiral antenna, fluxgate excitation coil, fluxgate induction coil and electromagnetic induction coil are formed using an electroplating process or a liquid metal casting process.
13. The single chip integrated current sensor of claim 9, wherein the planar spiral antenna is an equiangular spiral antenna or an archimedes spiral antenna.
14. The single chip integrated current sensor of claim 9, wherein the antenna element is butterfly, bar, plate or sheet shaped.
15. The single chip integrated current sensor of claim 1, wherein the current measurement unit further comprises a fluxgate closed loop feedback coil wound on a magnetic core.
16. The single chip integrated current sensor of claim 1 wherein the magnetic core is a thick film structure formed from a soft magnetic material.
17. The single chip integrated current sensor of claim 1, wherein the magnetic core is a thin film structure formed using an electroplating process.
18. The single chip integrated current sensor of claim 1, wherein the magnetic core is rectangular, triangular, annular, or racetrack in shape.
19. The single chip integrated current sensor of claim 1 wherein the fluxgate excitation coil, fluxgate induction coil, and electromagnetic induction coil are solenoid coil structures.
20. The manufacturing method of the single-chip integrated current sensor is characterized in that the single-chip integrated current sensor comprises a current measuring unit, an electromagnetic induction energy taking unit and a wireless communication unit, wherein the current measuring unit comprises a magnetic core, a fluxgate excitation coil and a fluxgate induction coil, the electromagnetic induction energy taking unit comprises the magnetic core and the electromagnetic induction coil, and the wireless communication unit comprises a planar antenna;
The manufacturing method of the single-chip integrated current sensor comprises the following steps:
forming a bottom metal coil and a planar spiral metal coil serving as a planar antenna on a semiconductor wafer;
Manufacturing a magnetic core on the bottom metal coil, wherein the magnetic core is used as a magnetic core of the current measuring unit and a magnetic core of the electromagnetic induction energy taking unit;
And forming a top metal coil on the surface of the magnetic core, wherein the bottom metal coil and the top metal coil form a fluxgate excitation coil, a fluxgate induction coil and an electromagnetic induction coil which are wound on the magnetic core, the fluxgate excitation coil and the fluxgate induction coil are used as the fluxgate excitation coil and the fluxgate induction coil of the current measuring unit, and the electromagnetic induction coil is used as the electromagnetic induction coil of the electromagnetic induction energy taking unit.
21. The method of manufacturing a single chip integrated current sensor according to claim 20, wherein forming the bottom metal coil and the planar spiral metal coil as the planar antenna on the semiconductor wafer comprises:
Depositing an insulating layer on the surface of the semiconductor wafer;
sputtering metal on the surface of the insulating layer to form a seed layer;
electroplating metal on the surface of the seed layer to form a bottom metal coil and a planar spiral metal coil.
22. The method of manufacturing a single chip integrated current sensor according to claim 21, wherein said fabricating a magnetic core on an underlying metal coil comprises:
the method comprises the steps of electroplating magnetic materials on a bottom metal coil to form a magnetic core, or placing a prefabricated magnetic core on the bottom metal coil, wherein the prefabricated magnetic core is a thick film magnetic core formed by processing soft magnetic materials.
23. The method of manufacturing a single chip integrated current sensor according to claim 21, wherein forming the top metal coil on the surface of the magnetic core comprises:
And electroplating metal on the surface of the magnetic core to form a top metal coil, and removing the residual seed layer.
24. The method of manufacturing a single chip integrated current sensor according to claim 20, wherein forming the bottom metal coil on the semiconductor wafer comprises:
etching a groove on a semiconductor wafer;
depositing an insulating layer in the groove;
and casting liquid metal or alloy material in the groove with the insulating layer to form the bottom metal coil.
25. The method of manufacturing a single chip integrated current sensor according to claim 24, wherein said fabricating a magnetic core on an underlying metal coil comprises:
And placing a prefabricated magnetic core in the groove with the bottom metal coil, wherein the prefabricated magnetic core is a thick film magnetic core formed by processing soft magnetic materials.
26. The method of manufacturing a single chip integrated current sensor according to claim 25, wherein forming the top metal coil on the surface of the magnetic core comprises:
bonding the semiconductor wafer with the magnetic core;
And etching a casting groove of the top metal coil on the semiconductor wafer, and casting liquid metal or alloy material to form the bottom metal coil.
27. The method of manufacturing a single chip integrated current sensor of claim 20, further comprising:
a bottom metal coil and a top metal coil are formed on a semiconductor wafer as closed loop feedback coils of the fluxgate.
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