CN105527589B

CN105527589B - Magnetometer

Info

Publication number: CN105527589B
Application number: CN201410514112.9A
Authority: CN
Inventors: 温瓌岸; 江泰维
Original assignee: SAGA GROUP Ltd
Current assignee: SAGA GROUP Ltd
Priority date: 2014-09-29
Filing date: 2014-09-29
Publication date: 2019-02-19
Anticipated expiration: 2034-09-29
Also published as: CN105527589A

Abstract

A kind of magnetometer, the mass block to suspend including one, one group of Y-direction displacement detection electrode, one group of Z-direction displacement detection electrode and an electric current supply module；Wherein, the mass block, the Y-direction displacement detection electrode and Z-direction displacement detection electrode respectively include several metal layers and the dielectric layer between wantonly two metal interlevel；In the mass block, corresponding to the part of the Y-direction displacement detection electrode, and corresponding to the part of the Z-direction displacement detection electrode, there are at least two metal layers to connect by through-hole respectively；The Y-direction displacement detection electrode includes two groups of electrodes, and each group includes at least two layers metal layer connected by through-hole, which also includes two groups of electrodes, and each group includes at least two layers metal layer connected by through-hole；And the electric current supply module supplies the selectable electric current for flowing through the mass block along the X-direction or Y-direction respectively.

Description

Magnetometer

Technical Field

The invention relates to a miniature magnetometer, in particular to a miniature magnetometer capable of measuring three-axis magnetic quantity simultaneously.

Background

Miniature magnetometers are a component that is widely used in, for example, smart phones, wearable devices, and Internet of Things devices (Internet of Things-IOT-devices). The miniature magnetometer can also be applied in other engineering, scientific and industrial fields. To provide magnetometry functionality in modern applications, miniature magnetometers must be highly integrated, consume less power, and provide accurate magnetometers/magnetic field measurements.

Among various miniature magnetometers, magnetometers manufactured by applying the Lorentz force (the Lorentz forces) principle are more practical. Since such a miniature magnetometer can be fabricated in a standard CMOS process. The novel miniature magnetometer structure works by applying the Lorentz force principle.

Magnetometers applying lorentz forces basically comprise a mass suspended by springs on a structure or a substrate. Providing a certain current to the mass block, wherein the current and the magnetic force generated by the earth magnetic field or other magnetic objects can generate a Lorentz force to move the mass block to the direction vertical to the current direction and the magnetic force direction. The detecting electrodes are usually formed into comb-shaped or finger-shaped, and are interlaced with the comb-shaped or finger-shaped formed at the edge of the mass block and maintain a distance; a capacitance is equal between the two. The detecting electrode can detect capacitance value change generated by relative position change between the mass block and the detecting electrode due to the movement of the mass block, and generate a detecting signal. The detection signal is converted into a voltage form and then used as an output signal. The generated output signal represents the displacement direction and displacement of the mass block under the influence of magnetic force, and the magnetic force value can be calculated accordingly.

The known miniature magnetometers are manufactured by a micro-electro-mechanical process or a CMOS process, so that the miniature magnetometers are extremely small in size and can only provide measurement of magnetic quantity in a single direction. Several designs have been proposed by those in the industry to measure the amount of magnetic flux in two directions in the same plane by a single magnetometer. But this design does not measure the magnetic flux in a third direction perpendicular to the plane.

WO2013159584a1 discloses a micromechanical magnetic field sensor that can measure magnetic quantities in both XY directions simultaneously. However, this invention does not provide a magnetic quantity measurement in the Z direction, i.e., perpendicular to the XY plane.

US 8,637,943B1 discloses a multi-axis integrated micro-electromechanical device comprising 3 sets of magnetometers for measuring 3 axes of magnetic flux.

US2012/0007597a1 discloses a micromechanical magnetometer structure using a set of XY axis magnetic force detectors and a set of Z axis magnetic force detectors to provide three axis magnetometry. Wherein, the XY axis magnetic force detector and the Z axis magnetic force detector are different types of detectors.

US 8,390,283B2 provides a three axis magnetometer using 3 wheatstone bridges of sensors via magnetic tunnel junctions providing a three axis magnetometric sensing function.

There is a need in the art to provide a novel structure of a miniature magnetometer to provide a three-axis magnetometric detection function.

It is also desirable to provide a novel micro magnetometer architecture that can use a single mass block to provide a three axis magnetometric sensing capability.

It is also desirable to provide a magnetometer that integrates the three-axis magnetometric function into a single proof mass using standard CMOS process characteristics.

Disclosure of Invention

The invention provides a magnetometer capable of measuring three-axis magnetic force by using a single mass block.

The invention also provides a magnetometer integrating the three-axis magnetometric function into a single mass block by using the standard CMOS process characteristics

The magnetometer comprises a suspended mass block, a group of Y-direction displacement detection electrodes, a group of Z-direction displacement detection electrodes and a current supply module. The Y direction represents one of two perpendicular directions on a plane where the mass is located, and the Z direction represents a direction perpendicular to the plane. The length direction of the mass block is parallel to the Y direction, and the mass block comprises a plurality of metal layers and a plurality of dielectric layers which are formed in a mode of alternately stacking the dielectric layers and the metal layers; the Y-direction displacement detection electrode and the Z-direction displacement detection electrode respectively comprise a plurality of metal layers and a dielectric layer between any two metal layers. Wherein, in the mass block, at least two metal layers are connected through a through hole (via) at the part corresponding to the Y-direction displacement detection electrode; at least two metal layers are connected through a via hole at a portion corresponding to the Z-direction displacement detection electrode. And the Y-direction displacement detection electrode comprises two groups of electrodes, each group comprises at least two metal layers connected through a through hole, the Z-direction displacement detection electrode also comprises two groups of electrodes, and each group comprises at least two metal layers connected through a through hole. The current supply module supplies current flowing through the mass block. The via hole may be filled with a metal material. In the mass block, a portion corresponding to the Y-direction displacement detection electrode and a portion corresponding to the Z-direction displacement detection electrode may be located on different planes or on the same plane. If they are located on the same plane, the two parts are electrically insulated from each other.

The magnetometer may further include a detection circuit for calculating X, Y, Z magnetic quantities in three directions according to the direction of the current flowing through the mass block of the current supply module and the output of the Y-direction displacement detection electrode or the Z-direction displacement detection electrode, corresponding to the power supply state of the current supply module. The X direction is a direction perpendicular to the Y direction on the plane of the mass block.

In some preferred embodiments of the present invention, the mass block, the Y-direction displacement detecting electrode and the Z-direction displacement detecting electrode are formed on a structure comprising a plurality of metal layers and a plurality of dielectric layers stacked in sequence, and the mass block is separated from the Y-direction displacement detecting electrode and the Z-direction displacement detecting electrode by a space. In this case, the Y-direction displacement detection electrode and the Z-direction displacement detection electrode are formed to have finger-like extensions extending toward the X/Y plane on a side close to the mass block; the mass block is also formed on the side surface close to the Y-direction displacement detection electrode and the Z-direction displacement detection electrode, extends to the X/Y plane and extends into the concave part formed by the finger extension of the Y-direction displacement detection electrode and the Z-direction displacement detection electrode.

In the above embodiments, the Y-direction displacement detecting electrodes are located on the first and second metal layers of the structure. In this case, the first set of electrodes of the Y-direction detecting electrodes may include a plurality of finger electrodes, and the second set of electrodes may also include a plurality of finger electrodes, the finger electrodes of the first set of electrodes and the finger electrodes of the second set of electrodes being arranged alternately, such that a pair of finger electrodes including a first set of electrode finger electrodes and a second set of electrode finger electrodes extends corresponding to a finger of the proof mass. In a preferred embodiment, the magnetometer includes two groups of Y-direction displacement detection electrodes, each group of Y-direction displacement detection electrodes includes two groups of electrodes, which are located on the first and second metal layers of the structure. Preferably, the first and second metal layers of each set of electrodes of the Y-direction displacement detection electrode are connected by a via.

In the above embodiment, the Z-direction displacement detecting electrodes are respectively located on the third and fourth metal layers, and the fifth and sixth metal layers of the structure; the third and fourth metal layers and the fifth and sixth metal layers are located at different heights in the Z direction. In a preferred embodiment, the magnetometer comprises two groups of Z-direction displacement detection electrodes, each group of Z-direction displacement detection electrodes comprises two groups of electrodes, a third metal layer and a fourth metal layer, and a fifth metal layer and a sixth metal layer, which are respectively positioned on the structure; the third and fourth metal layers are located above the fifth and sixth metal layers. That is, the first group of electrodes of the first group of Z-direction displacement detection electrodes and the first group of electrodes of the second group of Z-direction displacement detection electrodes are located on the same plane, and the second group of electrodes of the first group of Z-direction displacement detection electrodes and the second group of electrodes of the second group of Z-direction displacement detection electrodes are located on the same plane. The first and second metal layers and the third to sixth metal layers are kept a predetermined distance by at least one dielectric layer.

In the above embodiment, it is preferable that the third and fourth metal layers of the Z-direction displacement detection electrode are connected by a via, and the fifth and sixth metal layers thereof are also connected by a via. The via hole may be filled with a metal material. Furthermore, the first and second metal layers of the mass block can also be connected by a through hole, and the fourth and fifth metal layers are connected by a through hole. The via hole may be filled with a metal material. The Y-direction displacement detection electrodes may be located on both sides of the mass block in the X-direction, and the two Z-direction displacement detection electrodes are also located on both sides of the mass block in the X-direction.

The mass block is provided with at least 4 contact points, and can be electrically linked with the current supply module, so that the current supplied by the current supply module can selectively flow through the mass block along the X direction or the Y direction respectively.

The detection circuit is connected with the current supply module and each group of electrodes of the Y-direction displacement detection electrode and the Z-direction displacement detection electrode so as to detect capacitance change between the Y-direction displacement detection electrode and the part of the mass block corresponding to the Y-direction displacement detection electrode synchronously with the operation of the current supply module, so as to detect the displacement of the mass block in the Y direction under the action of a magnetic field; and detecting the capacitance change between the Z-direction displacement detection electrode and the part of the mass block corresponding to the Z-direction displacement detection electrode so as to measure the displacement of the mass block in the Z direction under the action of the magnetic field. The detection circuit can further calculate the magnetic quantity of the magnetic field in each direction of X/Y/Z according to the flowing direction of the current and the displacement of the Y/Z direction.

In a preferred embodiment of the present invention, the detection circuit measures a displacement of the mass block in the Z direction when the current supply module applies a current in the X direction to the mass block, so as to calculate a magnetic force of the mass block in the Y direction; the detection circuit measures the displacement of the mass block in the Y direction when the current supply module applies current in the X direction to the mass block, and calculates the magnetic force of the mass block in the Z direction according to the displacement; the detection circuit measures the displacement of the mass block in the Z direction when the current supply module applies current in the Y direction to the mass block, so as to calculate the magnetic force of the mass block in the X direction.

Drawings

FIG. 1 is a plan view of a magnetometer structure made in accordance with the present invention.

Fig. 2 is a schematic diagram of an electrode structure according to an embodiment of the invention.

Fig. 3 is a plan view of the electrode structure of fig. 2 for explaining the structures of the Y-direction displacement detection electrodes 211A, 211B, 221A, 221B.

Fig. 4 shows a system diagram of a magnetometer of the present invention.

FIG. 5 is a flow chart of a method for measuring magnetic flux in each direction by using the detection circuit of the present invention.

Drawings

100 magnetometer structure

10 mass block

10A, 10A etched hole

21. 22 finger electrode structure

21a, 22a space

30 power supply module

40 detection circuit

101. 102 spring

107. 108 common electrode

103. 104, 105, 106 electrical contact

211. 221 finger-shaped electrode plate

211A, 211B, 221A, 221B displacement detecting electrodes

212. 213, 222, 223 displacement detecting electrode

Detailed Description

The following describes the present invention according to a preferred embodiment thereof. It should be understood, however, that the preferred embodiments of the present invention are merely illustrative of the preferred embodiments of the present invention. The scope of the invention is not limited to the examples set forth in the specification.

FIG. 1 is a plan view of a magnetometer structure made in accordance with the present invention. As shown, the magnetometer structure 100 comprises a mass 10 and two sets of finger electrode structures 21, 22 located on either side thereof. The proof mass 10 and the two finger electrode structures 21 and 22 are shown to be structures fabricated by standard CMOS process, and the proof mass 10 and the two finger electrode structures 21 and 22 are electrically isolated by spaces 21a and 22a, respectively. If the structure is fabricated in standard CMOS processes, the two sets of finger electrode structures 21, 22 may comprise 6 metal layers and dielectric layers between the two metal layers and at the top and bottom layers, and are located on a substrate (not shown). The two sets of finger electrode structures 21 and 22 are located on the plane, and extend out of a plurality of finger electrode plates 211 and 221 in the X direction in the figure. In the following description, when the extending direction of the finger electrode plates 211 and 221 is the X direction, the direction perpendicular to the X direction on the same plane is the Y direction, as shown by the coordinates in the drawing. The direction perpendicular to this plane is referred to as the Z direction.

The proof mass 10 is located in the structure defined by the two sets of finger electrode structures 21, 22. In the example shown in the figure, the mass 10 has a rectangular shape, and the length direction is parallel to the Y direction. If the structure is fabricated in a standard CMOS process, the proof mass 10 may comprise fewer metal layers than the two sets of finger electrode structures 21, 22, e.g., 6 metal layers, and dielectric layers between any two metal layers and at the top and bottom layers, and be suspended above the substrate. The space between the proof mass 10 and the substrate, and the spaces 21a and 22a between the proof mass 10 and the two sets of finger electrode structures 21 and 22, may be formed by standard CMOS process techniques, such as etching. To form these spaces, the mass 10 may have to be provided with etching holes 10A, 10A to facilitate the manufacturing process. The etch holes 10A, 10A are not subject to any technical limitation. To maintain the suspension of the mass 10, the mass 10 is fixed to the structure 100 by springs 101 and 102. A plurality of finger-like extensions are respectively extended from two sides of the mass block 10 in the X direction, enter a space formed between any two finger-like extensions of the finger-like electrode plates 211, 221 of the finger-like electrode structures 21, 22, and keep a certain distance from the finger-like electrode plates 211, 221.

The support springs 101, 102 of the mass 10 are connected to an electrical contact 103, 104, 105, 106 at an end away from the mass 10, so that an external current, such as the current supplied by the power supply module 30 (fig. 4), can flow through the mass 10 selectively in the X direction or the Y direction through the electrical contact 103, 104, 105, 106. That is, current flows from the contacts 103 and 104, through the springs 101 and 101, flows through the mass 10 in the negative Y direction, and then flows through the supporting springs 102 and 102 to the contacts 105 and 106, as shown by the arrow a. Conversely, when the fluid flows in from the contacts 103 and 105, it flows through the mass 10 in the X direction and then flows out from the contacts 104 and 106, as shown by the arrows B. Furthermore, if current flows in through the contacts 104, 106, it flows through the mass 10 in the negative X direction and then flows out through the contacts 103, 105.

The magnetometer having the above main structure can measure the magnetic field at a specific location by measuring the Lorentz force. According to the Lorentz Force Law, when a certain intensity of current is applied to a mass block, the applied current and the magnetic Force existing on the earth generate Lorentz Force. The Lorentz force generated can move the mass block to a direction perpendicular to the current direction and the magnetic force direction at the same time. For example, in the example shown in the figure, when current flows through the mass 10 in the negative Y direction in the figure, magnetic force in the X direction in the figure pulls the mass 10 away from the figure (positive Z direction). Therefore, the displacement of the mass block in the Z direction after supplying the constant current in the negative Y direction is calculated, and the magnetic quantity in the X direction can be measured.

On the other hand, when a constant current in the X direction is applied to the mass, the magnetic force in the Y direction pulls the mass 10 in the positive Z direction in the figure. Therefore, the displacement of the mass block in the Z direction after supplying the constant current in the X direction is calculated, that is, the magnetic quantity in the Y direction can be measured. Conversely, when a constant current in the X direction is applied to the mass, the magnetic force in the Z direction pulls the mass 10 in the negative Y direction in the figure. Therefore, the displacement of the mass block in the Y direction after supplying the constant current in the X direction is calculated, that is, the magnetic quantity in the Z direction can be measured.

In order to provide effective measurement of the movement of the proof mass 10 in the X/Y direction and the Z direction, the preferred embodiment of the present invention utilizes through holes (vias) connecting two adjacent metal layers to form the electrodes required for measuring the mass displacement, i.e., the common electrode located in the proof mass 10, and the Y direction displacement measuring electrode and the Z direction displacement measuring electrode located in the finger electrode structures 21 and 22. Fig. 2 is a schematic diagram of an electrode structure according to an embodiment of the present invention. In the embodiment shown, the finger electrode structures 21, 22 are located on both sides of the proof mass 10. The metal layers 1 and 2 (M5 and M6) of the mass 10 are connected by vias to form an electrical connection. The metal layers (M2, M3) of the 4 th and 5 th layers are also connected through the through holes to form electrical connection. Meanwhile, the 1 st and 2 nd metal layers (M5, M6) of the finger electrode structures 21 and 22 are connected through vias to form electrical connections. The metal layers 3 and 4 (M3 and M4) and the metal layers 5 and 6 (M1 and M2) are respectively connected through the through holes to form electrical connection respectively. If necessary, each via hole may be filled with a metal.

Under the above-mentioned structure, the M5/M6 metal layers of the finger electrode structures 21, 22 form the Y-direction displacement detection electrodes 211A, 211B, 221A, 221B of the finger electrode structures 21, 22. The electrodes 211, 221 are fixed to the finger electrode structures 21, 22 and do not move. Fig. 3 is a plan view of the electrode structure according to the embodiment of the present invention, for explaining the structures of the Y-direction displacement detection electrodes 211A, 211B, 221A, 221B. As shown, electrodes 211A, 211A form a first set of electrodes of the first group of Y-direction detection electrodes, and electrodes 211B, 211B form a second set of electrodes of the first group of Y-direction detection electrodes; the electrodes 221A, 221A form a first group of electrodes of the second group of Y-direction detecting electrodes, and the electrodes 221B, 221B form a second group of electrodes of the second group of Y-direction detecting electrodes. The electrodes belonging to the same group are electrically connected and electrically isolated from the electrodes of other groups. The conductive lines L1, L2, L3, and L4 in the figure show the electrical connection, but not the physical connection. The electrodes of each group can form a wire by using different metal layers to form connection and isolation. For example, the first group of electrodes 211A, 211A of the first group of Y-direction detecting electrodes may be wired with the first metal layer M6, and the second group of electrodes 211B, 211B may be wired with the second metal layer M5. And the rest can be analogized. Each set of electrodes is connected to a detection circuit 40 (fig. 4) via the conductive lines.

As shown in FIG. 2, the M5/M6 metal layers of the proof mass 10 form a common electrode 107 that moves when the magnetometer is subjected to Lorentz forces. The component of the motion in the Y direction (direction of arrow Y in fig. 3, i.e., the Y direction in fig. 1) changes the respective distances between the common electrode 107 and the Y-direction displacement detection electrodes, the first set of electrodes 211A, 221A and the second set of electrodes 211B, 221B, thereby causing a corresponding change in the capacitance between the common electrode 107 and the Y-direction displacement detection electrodes. The variation is detected by the Y-direction displacement detection electrodes 211A, 211B, 221A, 221B, and then sent to the subsequent detection circuit 40 (fig. 4) to be converted into, for example, a voltage signal, so as to calculate the Y-direction displacement.

Similarly, the M3/M4 and M1/M2 metal layers of the finger electrode structures 21, 22 in FIG. 2 form the Z-direction displacement detection electrodes 212, 213 and 222, 223 of the finger electrode structures 21, 22, respectively. The electrodes 212, 213 and 222, 223 are fixed to the finger electrode structures 21, 22 and do not move. The M2/M3 metal layers of the proof mass 10 form a common electrode 108 that moves when the magnetometer is subjected to Lorentz forces. The component of the motion in the Z direction (the direction of arrow Z) changes the respective distances between the common electrode 108 and the Z-direction displacement detection electrodes 212, 213 and 222, 223, so that the capacitances between the common electrode 108 and the Z-direction displacement detection electrodes 212, 222 and between the common electrode 108 and the Z-direction displacement detection electrodes 213, 223 change accordingly. The variation is detected by the Z-direction displacement detection electrodes 212, 213 and 222, 223, and then sent to the post-stage detection circuit 40 (fig. 4) to be converted into, for example, a voltage signal, so as to calculate the Z-direction displacement.

In the present embodiment, the Y-direction displacement detecting electrodes include two groups, i.e., a first group of electrodes 211A and 211B and a second group of electrodes 221A and 221B, respectively located on two sides of the proof mass 10 in the X-direction. The Z-direction displacement detecting electrodes also include two groups, i.e., a first group of electrodes 212 and 213 and a second group of electrodes 222 and 223, which are also respectively located on two sides of the mass 10 in the X-direction. However, those skilled in the art will appreciate that the detection electrodes need only comprise one group. And the use of more than two groups is also feasible.

Although the above structure uses a specific metal layer as the detecting electrode and the common electrode, it is known to those skilled in the art that the metal layer combination used as the detecting electrode and the common electrode of the present invention can be utilized in a standard CMOS structure, and is not limited to the embodiment shown. Furthermore, the magnetometer structure of the present invention is not limited to be fabricated by using a CMOS process, and any fabrication method for forming a stack structure of a metal layer and a dielectric material layer can be used to fabricate the magnetometer of the present invention. In addition, the X/Y direction displacement detection electrodes and the Z direction displacement detection electrodes of the above embodiments, and the corresponding common electrodes are not formed on the same plane. But can also be formed on the same plane by simple change, thereby reducing the thickness of the structure.

The material of the metal layer is not particularly limited, and the metal layer can be applied to the present invention as long as it has excellent electrical conductivity and is suitable for processing. Suitable materials include: copper, silver, gold, aluminum, and alloys thereof. The material of the through hole and the filling material thereof is not particularly limited, and the through hole and the filling material thereof can be applied to the present invention as long as the through hole has excellent electrical conductivity and is suitable for processing. Suitable materials include: copper, silver, gold, aluminum, and alloys thereof. The material of the metal layer may be the same as or different from the material of the via and its fill. Preferably, a high dielectric material such as silicon or metal oxide, oxynitride, etc. is used for the dielectric layer. The thickness of each metal layer and dielectric layer is not limited, but if the magnetometer is fabricated by a standard CMOS process, the thickness of each metal layer and dielectric layer is preferably the same as the standard process specification, so as to simplify the process.

The mass 10 is preferably suspended from the structure by springs 101, 102. The springs 101, 102 may generally comprise several metal layers and dielectric layers between the metal layers. The metal and dielectric layers of the springs 101, 102 are preferably the same as the mass 10 and the finger electrode structures 21, 22. But this is not a technical limitation. Techniques for fabricating suspended mass and finger electrode structures are known in the art. And need not be described in detail herein.

Fig. 4 shows a system diagram of a magnetometer of the present invention. As shown in the figure, the magnetometer includes the above-mentioned suspended mass 10, finger electrode structures 21 and 22 located at both sides of the mass, a power supply module 30 for supplying current to the electrical contacts 103, 104, 105 and 106 of the mass 10, detection electrodes 211A, 211B, 221A, 221B and 212, 213 and 222 and 223 connected between the power supply module 30 and the finger electrode structures 21 and 22, and a detection circuit 40 for detecting the displacement of the mass 10 in the Y direction and the Z direction. The detection circuit 40 may be equipped with or externally connected to a microcontroller or a microcomputer (not shown) to calculate the displacement of the mass 10 in the Y direction and the Z direction, and convert the displacement in the Y direction and the Z direction into the magnetic flux of the earth magnetism or other magnetic fields in the X, Y, Z direction with reference to the operation mode information of the power supply module 30, including the direction of the current flowing through the mass.

The detection circuit 40 calculates the magnetic field according to the displacement of the mass 10, which is a conventional technique. And need not be described in detail herein. The detection/calculation method used by the detection circuit 40 in response to the particular configuration of the magnetometer 100 of the present invention will now be described. FIG. 5 is a flow chart of a method for measuring the magnetic flux in each direction by the detection circuit 40 according to the present invention. It should be noted that the method is not limited to any technical limitation, and the method is used for calculating X, Y, Z the magnetic force sequence. The correct results can still be obtained by calculation in a different order.

The magnetometer structure may be fabricated separately and combined with, for example, the power supply module 30, detection circuitry 40, etc. However, the power supply module 30, the detection circuit 40 and other circuit structures can be fabricated together in the same structure to simplify the interface therebetween.

As shown in fig. 5, when measuring the magnetic field, the power supply module 30 is first set 501 to supply a constant current in the Y direction of fig. 1 to the mass block 10. That is, current is caused to enter the mass 10 from the contacts 103, 104 and exit from the contacts 105, 106, or to enter the mass 10 from the contacts 105, 106 and exit from the contacts 103, 104. After the current is stabilized in step 502, the displacement of the proof mass in the Z direction is measured, and the magnetic flux in the X direction is calculated according to the Z direction displacement in step 503.

Then, in step 504, the power supply module 30 supplies the constant current in the X direction of fig. 1 to the mass block 10. That is, current is caused to enter mass 10 through contacts 103, 105 and exit through contacts 104, 106. After the current is stabilized in step 505, the displacement of the mass in the Z direction is measured, and the magnetic flux in the Y direction is calculated according to the Z direction displacement in step 506.

Then, in step 507, the power supply module 30 supplies the constant current in the X direction to the mass block 10. After the current is stabilized in step 508, the displacement of the proof mass in the Y direction is measured, and the magnetic flux in the Z direction is calculated in step 509 according to the displacement in the Y direction. Thus, the measurement of the magnetic field in the X/Y/Z directions is completed.

The three-dimensional magnetic quantity measured by the magnetometer can be applied to various applications, such as longitude and latitude judgment, altitude judgment and the like. The invention provides a magnetometer which has simple design and easy manufacture and is completely compatible with standard CMOS (complementary metal oxide semiconductor) manufacture procedures. The magnetometer can accurately measure the magnetic quantity of three-dimensional space by applying simple circuit control. It is an invention which has not been found before.

Claims

1. A magnetometer comprises a suspended mass block, a group of Y-direction displacement detection electrodes, a group of Z-direction displacement detection electrodes and a current supply module;

the Y direction represents one of two vertical directions on a plane where the mass block is located, the other of the two vertical directions on the plane where the mass block is located is an X direction, and the Z direction represents a direction perpendicular to the plane; wherein,

the length direction of the mass block is parallel to the Y direction, and the mass block comprises a plurality of metal layers and a plurality of dielectric layers which are formed in a mode of alternately stacking the dielectric layers and the metal layers;

the Y-direction displacement detection electrode and the Z-direction displacement detection electrode respectively comprise a plurality of metal layers and dielectric layers between any two metal layers;

in the mass block, at least two metal layers are connected through a through hole corresponding to the Y-direction displacement detection electrode; at least two metal layers are connected through a through hole at the part corresponding to the Z-direction displacement detection electrode; and

the Y-direction displacement detection electrode comprises two groups of electrodes, each group comprises at least two metal layers connected through a through hole, the Z-direction displacement detection electrode also comprises two groups of electrodes, and each group comprises at least two metal layers connected through a through hole; and

the current supply module supplies current which can selectively flow through the mass block along the X direction or the Y direction respectively.

2. A magnetometer according to claim 1 wherein: the through hole is filled with a metal material.

3. A magnetometer according to claim 1 wherein: in the mass block, a portion corresponding to the Y-direction displacement detection electrode and a portion corresponding to the Z-direction displacement detection electrode are located on different planes.

4. A magnetometer according to claim 1 wherein: in the mass block, a portion corresponding to the Y-direction displacement detection electrode and a portion corresponding to the Z-direction displacement detection electrode are located on the same plane and electrically insulated from each other.

5. A magnetometer according to claim 1 wherein: the detection circuit is used for calculating X, Y, Z magnetic quantities in three directions according to the direction of current flowing through the mass block of the current supply module and the output of the Y-direction displacement detection electrode or the Z-direction displacement detection electrode corresponding to the power supply state of the current supply module; wherein, the X direction is a direction perpendicular to the Y direction on the plane of the mass block.

6. A magnetometer according to claim 1 wherein: the Y-direction displacement detection electrode and the Z-direction displacement detection electrode are arranged on one side close to the mass block and form finger-shaped extension extending to an X/Y plane, and the X/Y plane is a plane formed in the X direction and the Y direction; the mass block is also formed on the side surface close to the Y-direction displacement detection electrode and the Z-direction displacement detection electrode, extends to the X/Y plane and extends into the concave part formed by the finger extension of the Y-direction displacement detection electrode and the Z-direction displacement detection electrode.

7. A magnetometer according to claim 1 wherein: the mass block, the Y-direction displacement detection electrode and the Z-direction displacement detection electrode are formed on a structure comprising a plurality of metal layers and a plurality of dielectric layers which are stacked in sequence, and the mass block is separated from the Y-direction displacement detection electrode and the Z-direction displacement detection electrode by a space.

8. The magnetometer of claim 7, wherein: the Y-direction displacement detection electrode is positioned on the first metal layer and the second metal layer of the structure; the Y-direction displacement detection electrodes include a first group of electrodes including a plurality of finger electrodes, a second group of electrodes including a plurality of finger electrodes, the finger electrodes of the first group of electrodes and the finger electrodes of the second group of electrodes being alternately arranged, and a pair of finger electrodes including a first group of electrode finger electrodes and a second group of electrode finger electrodes extending corresponding to a finger of the proof mass.

9. The magnetometer of claim 7, wherein: the magnetometer comprises a first group of Y-direction displacement detection electrodes and a second group of Y-direction displacement detection electrodes, wherein the first group of Y-direction displacement detection electrodes and the second group of Y-direction displacement detection electrodes respectively comprise two groups of electrodes which are positioned on a first metal layer and a second metal layer of the structure.

10. The magnetometer of claim 8, wherein: the first and second metal layers of each set of electrodes of the Y-direction displacement detection electrode are connected through a via hole.

11. A magnetometer according to claim 8 or 9 characterised in that: the Z-direction displacement detection electrodes are respectively positioned on the third metal layer, the fourth metal layer, the fifth metal layer and the sixth metal layer of the structure; the third and fourth metal layers and the fifth and sixth metal layers are located at different heights in the Z direction.

12. The magnetometer of claim 11, wherein: the magnetometer comprises a first group of Z-direction displacement detection electrodes and a second group of Z-direction displacement detection electrodes, wherein the first group of Z-direction displacement detection electrodes and the second group of Z-direction displacement detection electrodes respectively comprise two groups of electrodes, a third metal layer and a fourth metal layer, a fifth metal layer and a sixth metal layer which are respectively positioned on the structure; the third and fourth metal layers are located above the fifth and sixth metal layers.

13. The magnetometer of claim 12, wherein: the first and second metal layers and the third to sixth metal layers are kept a predetermined distance by at least one dielectric layer.

14. The magnetometer of claim 12, wherein: the third and fourth metal layers of the Z-direction displacement detection electrode are connected through a through hole, and the fifth and sixth metal layers are also connected through a through hole.

15. The magnetometer of claim 14, wherein: the first metal layer and the second metal layer of the mass block are connected through a through hole, and the fourth metal layer and the fifth metal layer are connected through a through hole.

16. A magnetometer according to claim 1 wherein: the mass block is provided with at least 4 contact points and is electrically connected with the current supply module, so that the current supplied by the current supply module can selectively flow through the mass block along the X direction or the Y direction respectively.

17. The magnetometer of claim 5, wherein: the detection circuit is connected with the current supply module, and each group of electrodes of the Y-direction displacement detection electrode and the Z-direction displacement detection electrode so as to detect capacitance change between the Y-direction displacement detection electrode and the part of the mass block corresponding to the Y-direction displacement detection electrode synchronously with the operation of the current supply module, so as to measure the displacement of the mass block in the Y direction under the action of a magnetic field; and detecting capacitance change between the Z-direction displacement detection electrode and the part of the mass block corresponding to the Z-direction displacement detection electrode so as to measure the displacement of the mass block in the Z direction under the action of the magnetic field.

18. The magnetometer of claim 17, wherein: the detection circuit further calculates the magnetic quantity of the magnetic field in each direction of X/Y/Z according to the flowing direction of the current and the displacement of the Y/Z direction.

19. The magnetometer of claim 5, wherein: the detection circuit measures the displacement of the mass block in the Z direction when the current supply module applies current in the X direction to the mass block, and calculates the magnetic force of the mass block in the Y direction according to the displacement; the detection circuit measures the displacement of the mass block in the Y direction when the current supply module applies current in the X direction to the mass block, and calculates the magnetic force of the mass block in the Z direction according to the displacement; the detection circuit measures the displacement of the mass block in the Z direction when the current supply module applies current in the Y direction to the mass block, and calculates the magnetic force of the mass block in the X direction according to the displacement.