WO2013159584A1

WO2013159584A1 - Micro-mechanical magnetic field sensor and preparation method thereof

Info

Publication number: WO2013159584A1
Application number: PCT/CN2013/071251
Authority: WO
Inventors: 熊斌; 吴国强; 徐德辉; 王跃林
Original assignee: 中国科学院上海微系统与信息技术研究所
Priority date: 2012-04-28
Filing date: 2013-02-01
Publication date: 2013-10-31
Also published as: CN102680917B; CN102680917A

Abstract

A micro-mechanical magnetic field sensor and a preparation method thereof relate to the field of micro-electro-mechanical systems. The preparation method comprises: manufacturing a metal coil (40) and pads (310, 311, 5) on a device structure layer; manufacturing a device structure by dry etching; and releasing the device structure to form a harmonic oscillator (6). The harmonic oscillator (6) of the micro-mechanical magnetic field sensor operates in an extension mode, so that the induced electromotive force generated by each section of metal cutting the magnetic induction line on the metal coil (40) can be superposed, thereby enhancing the intensity of an output signal. Moreover, the micro-mechanical magnetic field sensor has the advantages of low power consumption, a simple driving/detection circuit, slight influence by temperature, a simple process and the like, and has a high industrial value.

Description

Micro mechanical magnetic field sensor and preparation method thereof

Technical field

The invention relates to a magnetic field sensor, in particular to a micro-mechanical magnetic field sensor and a preparation method thereof, and belongs to the field of micro-mechanical magnetic field sensor design and micro-machining. Background technique

By sensing the direction of the Earth's magnetic field or navigating the ship, especially in the fields of navigation, aerospace, automation, military, and consumer electronics, magnetic field sensors are becoming more widely used. Magnetic field sensing technology is moving toward miniaturization, low power consumption, high sensitivity, high resolution, and compatibility with electronic devices. According to the working principle, the magnetic field sensor can be divided into: superconducting quantum interference magnetic field sensor, Hall magnetic field sensor, fluxgate magnetometer, giant magnetoresistive magnetic field sensor and induction coil magnetic field sensor.

The superconducting quantum interference magnetic field sensor has the highest sensitivity among all magnetic field sensors, but its structure is complex, bulky, expensive, and needs to work in a low temperature environment. The Hall magnetic field sensor has low power consumption and small size, and can measure static or dynamic magnetic fields. However, its sensitivity is low, noise level and static offset are large; fluxgate magnetometer is used to measure static or slowly changing magnetic field, high resolution, low power consumption, but large volume and low frequency response; giant magnetoresistance Magnetic field sensors are highly sensitive, but cannot measure large magnetic fields. Inductive coil magnetic field sensors are based on Faraday's law of electromagnetic induction to detect changing magnetic fields. They have low power consumption and simple structure (AL Herrera-May, LA Aguilera-Cort0s, PJ Garcia- Ramirez and E. Manjarrez, "Resonant magnetic field sensors based on MEMS technology", Sensors, vol. 9, no. 10, pp. 7875-7813, 2009. ). Inductive coil magnetic field sensors fabricated by MEMS (Micro Electro Mechanical System) technology are simple in structure and easy to process, and are compatible with CMOS IC (Complementary Metal Oxide Semiconductor Integrated Circuit) technology. MEMS magnetic field sensors have the advantages of small size, light weight, low power consumption, low cost, high reliability, excellent performance and powerful functions that are unmatched by traditional sensors. The development of MEMS technology has enabled micro-structure processing on the chip, while reducing the cost of MEMS, and can also accomplish tasks that many large-scale electromechanical systems cannot perform, which promotes the development of magnetic field sensors.

At present, the main working principle of the magnetic field sensor of the MEMS structure is: After the Lorentz force of the induction coil of the current is subjected to the magnetic field, the structure of the support coil is bent or twisted, and the method of capacitance detection or piezoresistive detection, optical detection, etc. The magnitude of the magnetic field signal can be detected by measuring the amount of torsional deformation or the amount of bending deformation of the supporting coil structure. These devices typically have inductive coils fabricated on cantilever beams, U-beams, or plates that can be bent or twisted. When the device is in operation, place the device in a magnetic field and apply current to the induction coil. The induction coil will be subjected to Lorentz force, Luo The Lenze force causes bending or twisting of the cantilever beam, U-beam or plate. By measuring the amount of bending or the amount of twist of the cantilever beam, U-beam or plate, the magnitude of the magnetic field can be detected. However, since these devices all need to pass current to the induction coil, their power consumption is relatively large; in addition, these devices generally operate in a bending mode or a torsional mode, and thus they operate at a lower resonance frequency.

In view of this, how to propose a micro-mechanical magnetic field sensor and a preparation method thereof can make the prepared sensor have the characteristics of small volume, simple structure, low power consumption, and anti-interference, and has become a technology to be solved by practitioners in the field. problem.

Summary of the invention

In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a micro-mechanical magnetic field sensor and a preparation method thereof for solving the problems of large power consumption, complicated structure, and poor anti-interference in the prior art.

To achieve the above and other related objects, the present invention provides a micromechanical magnetic field sensor and a method of fabricating the same. A method for preparing a micromechanical magnetic field sensor, comprising at least:

1) providing an SOI substrate;

2) depositing an electrically insulating dielectric layer on the top silicon of the SOI substrate, and performing a patterning process and an etching process on the electrically insulating dielectric layer to respectively preserve the pre-prepared resonant oscillator region, pre-prepare the test pad region, Pre-preparing the support beam region, and pre-preparing the electrically insulating dielectric layer of the anchor region;

3) preparing one or more metal coils on the electrically insulating dielectric layer corresponding to the resonant resonator region, forming a test pad in the test pad region, forming a metal pad in a portion of the anchor region, and Forming an electrode pad on the top silicon on the outer side of the periphery of the resonant oscillator region;

4) removing a portion of the top silicon by photolithography and deep reactive ion etching, forming drive electrodes, support beams, and anchor points corresponding to the electrode pads, the support beam regions, and the anchor regions, respectively, and then utilizing hydrofluoric acid The SOI substrate buried oxide layer below the resonant resonator region is etched away to release the device structure to form a resonant oscillator.

Optionally, when a cavity corresponding to the resonant oscillator region is pre-defined between the buried oxide layer of the SOI substrate and the top silicon in the step 1), the step 4) includes:

Partial top silicon is removed by photolithography and deep reactive ion etching, and driving electrodes, support beams, and anchor points are respectively formed in the electrode pads, the support beam regions, and the anchor regions, and the device structure is released to form a resonance. Vibrator.

Optionally, when a metal coil is prepared on the electrically insulating dielectric layer corresponding to the resonant oscillator region, the step 3) further includes:

Forming a metal thin film on the top silicon of the SOI substrate and on the electrically insulating dielectric layer corresponding to the resonant oscillator region, Patterning and etching the metal thin film to form a metal coil in the resonant resonator region, a test pad in the test pad region, a metal pad in a portion of the anchor region, and An electrode pad is formed on the top silicon outside the periphery of the resonant oscillator region.

Optionally, the metal coil is a circular or square coil that surrounds a circumference of the electrically insulating dielectric layer, and the beginning and the end of the coil are connected to the two test pads through the support beam.

Optionally, when a metal coil is prepared on the electrically insulating dielectric layer corresponding to the resonant oscillator region, the step

3) Also includes:

3-1) preparing a metal thin film on the top silicon and the electrically insulating dielectric layer corresponding to the resonant resonator region, and patterning and etching the metal thin film to form respectively in the resonant oscillator region a metal coil, forming a test pad in the test pad region, forming a metal pad in a portion of the anchor region, and forming an electrode pad on a top silicon outside a periphery of the resonant oscillator region;

3-2) depositing a layer of electrically insulating dielectric again, and photolithographically etching and etching to expose the first ends of the metal coil;

3-3) depositing a second metal thin film, and performing photolithography and etching to form a metal lead, and the beginning of the metal lead is connected to the beginning of the first metal coil, and the end is connected by a support beam Go to the test pad.

Optionally, the metal coil is a spiral metal coil surrounded by an inner and outer circumference of the corresponding center of the electrically insulating dielectric layer, the end of which is connected to the test pad through the support beam, the spiral The metal coil is a circular spiral or a square spiral; further optionally, the metal lead is a straight line, a curved line, or a broken line.

Optionally, when the multi-layer metal coil is on the electrically insulating medium layer corresponding to the resonant oscillator region, the step 3) further includes:

3-1) preparing a metal thin film on the electrically insulating dielectric layer corresponding to the resonant oscillator region, and patterning and etching the metal thin film to form a metal coil in the resonant oscillator region;

Repeating the processes of steps 3-1) and 3-2) in sequence to prepare a series connection of a plurality of metal coils; and in preparing the metal coil of the last layer, respectively, by the photolithography and etching processes in the test The pad region forms a test pad, forms a metal pad in a portion of the anchor region, and forms an electrode pad on the top silicon outside the periphery of the resonant oscillator region.

Optionally, the metal coil is a spiral metal coil surrounded by an inner and outer circumference of the corresponding center of the electrically insulating dielectric layer, the end of which is connected to the test pad through the support beam, the spiral The metal coil is a circular spiral or a square spiral. Further optionally, the serial connection mode of the multi-layer metal coil is continuous odd-numbered and even-numbered The metal coils are connected by a start end, and a continuous even number and an odd number of the metal coils are connected by ends, and each of the metal coils has the same winding direction and shape.

Optionally, one end of the support beam is connected to the resonant oscillator, and the other end is connected to the anchor point to fix the resonant oscillator; the test pad is located on an anchor point having the electrically insulating dielectric layer; The metal pad is located on an anchor point that does not have the electrically insulating dielectric layer.

Optionally, the metal coil or the metal lead is made of gold or aluminum; and the multi-layer metal coil has an electrically insulating dielectric layer except the joint.

Another object of the present invention is to provide a micromechanical magnetic field sensor, characterized in that it comprises at least:

An SOI substrate having a recess having a depth up to its buried oxide layer; at least one anchor point on a side of the recess; a resonant oscillator formed by top silicon of the SOI substrate and suspended in the recess a supporting beam, one end of which is connected to the resonant vibrator, and the other end is connected to the anchor point to support the resonant vibrator to hang in the recess; a metal coil is formed on the resonant vibrator; a disk formed on the anchor point, respectively connected to the beginning and the end of the metal coil, and each of the test pads is insulated from each other; a plurality of metal pads formed on a portion of the anchor points for The resonant oscillator applies a fixed potential; a driving electrode is disposed on the top silicon outside the periphery of the resonant oscillator for driving the resonant oscillator to vibrate.

Optionally, an insulating dielectric layer is disposed between the metal coil and the resonant oscillator; the metal coil is made of gold or aluminum; and the metal coil is a circular or square metal coil around a circumference of the resonant oscillator. And the beginning and the end of the metal coil are respectively connected to the two test pads through the support beam.

Optionally, the metal coil is a spiral metal coil surrounded by the center of the resonant resonator from the inside to the outside, and the beginning and the end thereof are connected to the test pad through the support beam, and the spiral metal coil is Round spiral or square spiral.

Optionally, the metal coil is composed of a plurality of the spiral metal coils connected in series with each other, and each of the spiral metal coils has the same winding direction, and the spiral metal coils are connected in series in a continuous odd number and an even number The beginning ends of the spiral metal coils are connected, and the ends of the consecutive even and odd-numbered spiral metal coils are connected, and each of the spiral metal coils connected in series has an electrically insulating dielectric layer except for the joint.

Optionally, the groove is a square groove, a circular groove, or an annular groove, and the resonant oscillator has a square structure, a circular structure, or a ring structure, corresponding to the shape of the groove.

As described above, a micro-mechanical magnetic field sensor and a method for fabricating the same have the following beneficial effects: The micro-mechanical magnetic field sensor of the present invention uses an electrostatic drive to excite a resonant oscillator to enter a resonant state, and the metal coil is located above the resonant oscillator. When the sensor is in the magnetic field, the resonant oscillator will drive the metal coil to move, the metal coil The magnetic induction line is cut to generate an induced electromotive force at both ends of the coil. Meanwhile, the resonant oscillator of the micromechanical magnetic field sensor proposed by the present invention operates in an expanded mode, and thus the induced electromotive force generated by each small piece of metal cutting magnetic line on the metal coil is superimposed on each other. The strength of the output signal is enhanced.

The method described in the present invention can also be used to prepare a micromechanical magnetic field sensor comprising a plurality of resonant oscillator structures. For example, when two resonant resonator structures are included in the micromechanical magnetic field sensor, those skilled in the art can separately prepare two resonant oscillator structures according to the same manufacturing process as the above method, and adjust the multiple layers according to actual conditions. Parameters such as the direction, series, shape and number of layers of the metal coil. Of course, those skilled in the art will also appreciate that the method of the present invention can also be used to fabricate micromechanical magnetic field sensors containing more than two resonant oscillator structures.

The micro-mechanical magnetic field sensor of the invention works by using an electrostatic driving device, does not need to pass current on the metal coil, reduces the power consumption of the device, and measures the magnitude of the magnetic field by measuring the induced electromotive force at both ends of the metal coil, and the driving-detecting circuit is simple. And the temperature is less affected; in the preparation process, there is no need to grow or deposit magnetic materials on the device, which reduces the complexity of the process; and the metal coil prepared by the invention can be one or more layers of spiral coils, which is beneficial to Further increase the intensity of the output signal and improve the accuracy of the detection. DRAWINGS

Figure la-li shows a process diagram for preparing a resonant resonator having a square metal coil in the present invention, wherein Figure Id is a cross-sectional view taken along line AB of Figure lc, and Figure lg is a cross-sectional view taken along the CD direction of Figure If.

2a-2b show process diagrams of a resonant resonator having a square metal coil fabricated on an SOI substrate of a predetermined cavity in the present invention.

3a-3k are diagrams showing the process of preparing a resonant resonator having a helical metal coil, wherein Fig. 3d is a cross-sectional view along the AB side of Fig. 3c, Fig. 3i is a cross-sectional view along the CD direction of Fig. 3h, and Fig. 3j is a cross-sectional view 3h section of the AB direction.

Figure 31 shows a cross-sectional view of Figure 3k.

4a-4b are process diagrams showing a resonant resonator having a spiral metal coil fabricated on an SOI substrate of a predetermined cavity in the present invention.

Figure 5 is a cross-sectional view showing a resonant resonator having two layers of helical metal coils prepared in the present invention.

6a-6b are cross-sectional views showing a resonant resonator having two layers of helical metal coils fabricated on an SOI substrate of a predetermined cavity in the present invention.

7a-7c are cross-sectional views showing a plan view of a resonant resonator having a square metal coil and two square grooves prepared in the present invention. Figure 8 is a plan view showing a resonant resonator having a helical metal coil prepared in the present invention.

Figure 9 is a cross-sectional view showing a resonant resonator having two layers of helical metal coils prepared in the present invention. Component label description

1 SOI substrate

10 substrate silicon

11 buried oxygen layer

12 top silicon

2 cavity

3 electrically insulating dielectric layer

30 resonant oscillator area

31 Test pad area

310 test pad

311 metal pad

32 support beam area

320 support beam

33 anchor area

330 anchor

4 metal film

40 metal coil

400 beginning

401 end

41 metal lead

5 electrode pads

50 drive electrode

6 resonant oscillator

7 groove specific embodiment

The embodiments of the present invention are described below by way of specific examples, and those skilled in the art can readily understand other advantages and effects of the present invention from the disclosure of the present disclosure. The invention may also be added by other different embodiments The details of the present invention can be variously modified or changed without departing from the spirit and scope of the invention.

Please refer to Figures la to li, Figures 2a to 2b, Figures 3a to 3k, 4a to 4b, 5, 6a to 6b, 7a to 7c, and 8 to 9. It should be noted that the illustrations provided in this embodiment merely illustrate the basic concept of the present invention in a schematic manner, and only the components related to the present invention are shown in the drawings, instead of the number and shape of components in actual implementation. Dimensional drawing, the actual type of implementation of each component's type, number and proportion can be a random change, and its component layout can be more complicated. In the embodiment of the present invention, a micro-mechanical magnetic field sensor including a resonant oscillator is described as an example for convenience of description.

The micromechanical magnetic field sensor and the method for fabricating the same according to the present invention will be further described below with reference to the accompanying drawings, and the drawings are not drawn to scale. Embodiment 1

As shown in FIG. 1 to FIG. Li, the present invention provides a method for preparing a micro-mechanical magnetic field sensor, comprising the following steps: Step 1: As shown in FIG. 1a, an SOI substrate 1 is provided, including a substrate silicon 10 and a buried oxide. Layer 11, and top silicon

12.

Step 2: As shown in FIG. 1b to FIG. 1D, a layer of electrically insulating dielectric layer 3 is thermally deposited or LPCVD on the top silicon of the SOI substrate 1 by patterning and engraving the electrically insulating dielectric layer 3. An etching process to retain an electrically insulating dielectric layer 3 corresponding to the resonant oscillator region 30, the pre-prepared test pad region 31, the pre-prepared support beam region 32, and the pre-prepared anchor region 33, wherein Figure lc is formed in this step Process plan, Figure Id is a cross-sectional view along the AB direction of Figure lc.

Specifically, the number of the support beam regions 32 is 1 to 4, respectively, and is preferably 4 in the embodiment, wherein the number of the support beam regions 32 that retain the electrically insulating dielectric layer 3 is 1 respectively. There are preferably two in the present embodiment, and the number of the corresponding anchor point regions 33 is also 1 to 4, and is preferably four in the present embodiment.

Specifically, the test pad area 31 has two, and each of the test pad areas 31 may be located on the anchor point area 33 having two electrically insulating dielectric layers 3, or may be located in the same one with electrical insulation. On the anchor region 33 of the dielectric layer 3, in the embodiment, preferably, the test pad region 31 is located at two adjacent anchor regions 33; the support beam region 32-end and the resonance The vibrator region 30 is connected to each other, and the other end is in contact with the anchor region 33; corresponding to the anchor region 33 having the electrically insulating dielectric layer 3, the support beam region 32 also has an electrically insulating dielectric layer 3 .

Step 3: As shown in FIG. 1 to FIG. 1g, on the top silicon 12 of the SOI substrate 1 and corresponding to the resonant oscillator region A metal thin film 4 is prepared on the electrically insulating dielectric layer 3 of the field 30 by a sputtering or evaporation process. The material of the metal thin film 4 may be aluminum or gold, but is not limited thereto, and then the metal thin film 4 is patterned. And a etch process to form a metal coil 40 on the electrically insulating dielectric layer 3 of the resonant oscillator region 30, the metal coil 40 being a circle around the circumference of the electrically insulating dielectric layer 3 of the resonant oscillator region 30 Or a square metal coil 40, preferably a square metal coil 40 in this embodiment; and then at the test pad region 31 having the electrically insulating dielectric layer 3, at an anchor point without the electrically insulating dielectric layer 3 A test pad 310, a metal pad 311, and an electrode pad 5 are respectively formed on the top layer silicon 12 on the outer side of the periphery of the resonant resonator region 30, wherein FIG. If is a process plan formed in the step, and FIG. Figure If the cross section of the CD direction.

Step 4: As shown in FIG. 1h to FIG. Li, part of the top silicon 12 is removed by photolithography and deep reactive ion etching, and driving is formed corresponding to the electrode pad 5, the support beam region 32, and the anchor region 33, respectively. The electrode 50, the support beam 320, and the anchor point 330 are then etched away by the hydrofluoric acid to the buried oxide layer 11 corresponding to the SOI substrate under the resonant resonator region 30 to release the device structure to form the resonant resonator 6. The driving electrode 50 is used to drive the resonant vibrator 6 to vibrate; one end of the supporting beam 320 is connected to the resonant vibrator 6 , and the other end is fixed to the anchor point 330 , so that the resonant vibrator 6 is suspended and fixed to the lining Above the bottom silicon 10; the resonant vibrators 6 are respectively square, circular, or annular in shape, and are preferably square in this embodiment.

Specifically, the metal coil 4 is located on the resonant vibrator 6 and has an electrically insulating dielectric layer 3 between the resonant resonator 6 and a periphery of the metal coil 4 located near an edge of the resonant vibrator 6 so that The resonant oscillator 6 obtains a large amplitude when it vibrates.

Both ends of the metal coil 4 are connected to the two test pads 310 through the support beam 320 having an electrically insulating dielectric layer 3, and the two test pads 310 may be located at one of the anchor points 330 or respectively In the present embodiment, the two test pads 310 are respectively located on two adjacent anchor points 330, and the metal pads 311 are located on the other two anchor points 330. For applying a fixed potential to the resonant vibrator 6.

Specifically, corresponding to the number of the support beam regions 32, the number of the support beams 320 is 1-4, which is preferably 4 in this embodiment; corresponding to the number of the anchor regions 33, the anchor The number of the points 330 is 1 to 4, respectively, and is preferably 4 in the present embodiment. The number of the electrode pads 5 is 1 to 4, respectively, in the present embodiment. Preferably it is four.

When the micromechanical sensor prepared by the method of the present embodiment operates in the expansion mode, each point on the resonant oscillator expands or contracts simultaneously with time. For these bulk modal resonators, the resonant frequency is relatively high, so the displacement of each point on the resonant oscillator changes faster with time. If a metal coil is formed on the resonator of the resonator, when the square plate resonator or the circular plate resonator operates in the expansion mode, the metal coil moves with the resonance oscillator. When the device is in a magnetic field In the middle, the metal coil cuts the magnetic field lines, thereby generating an induced electromotive force across the coil. By detecting the magnitude of the induced electromotive force at both ends of the metal coil, the magnitude of the magnetic field strength can be calculated. Since the resonant oscillator of the micromechanical magnetic field sensor proposed by the present invention operates in an expanding mode, the induced electromotive force generated by each small piece of metal cutting magnetic line on the metal coil is superimposed on each other, and the intensity of the output signal is enhanced.

In addition, the micro-mechanical magnetic field sensor of the present invention works by using an electrostatic driving device, does not need to pass current on the metal coil, reduces the power consumption of the device, and measures the magnitude of the magnetic field by measuring the induced electromotive force at both ends of the metal coil, driving-detecting The circuit is simple and has little influence on temperature; in the preparation process, it is not necessary to grow or deposit magnetic material on the device, which reduces the complexity of the process; further, the metal coil prepared by the invention may be one or more layers of spiral The coil is beneficial to further increase the intensity of the output signal and improve the accuracy of the detection. Embodiment 2

As shown in FIG. 2a, an SOI substrate is provided, and a cavity 2 is pre-formed between the top silicon 12 and the buried oxide layer 11 of the SOI substrate 1. The forming process of the cavity 2 is a person skilled in the art. A well-known conventional process: first, performing pattern lithography on the substrate silicon 10, and then etching a recess (not shown) deep to the buried oxide layer according to the lithographic pattern, the groove being a square groove A circular groove or an annular groove is preferably a square groove in this embodiment. Then, a layer of silicon oxide is thermally grown on the bottom of the groove and the sidewall of the periphery as a buried oxide layer 11, and finally a layer of silicon is bonded as a top layer of silicon 12 on the side having the groove, the top layer of silicon 12 and The cavity between the buried oxide layers 11 is the cavity 2 described.

The main difference between the process of preparing the device on the SOI substrate 1 of the preset cavity 2 and the first embodiment is as follows: In the embodiment, the structure of the resonant resonator 6 is also released while the device structure is fabricated. At this time, the resonant vibrator 6 is suspended above the buried oxide layer 11; and in the first embodiment, after the device structure is fabricated, the resonant vibrator 6 structure is not released, so it is necessary to etch away the resonant vibrator region 30 by using HF. The method of embedding the silicon oxide 11 in the SOI substrate 1 releases the structure of the resonant resonator 6, and the other process steps are the same as the corresponding steps in the fourth embodiment. The structure of the final device in this embodiment is as shown in FIG. 2b, and other process structure diagrams are the same as those in the embodiment 1, and are not described herein again. Embodiment 3

As shown in the figure, the present invention provides a method for preparing a micromechanical magnetic field sensor, comprising the following steps:

Step 1: As shown in FIG. 3a, an SOI substrate 1 is provided, including a substrate silicon 10, a buried oxide layer 11, and a top silicon layer.

12.

Step 2: As shown in FIG. 3b to FIG. 3d, an electrically insulating dielectric layer 3 is deposited on the top silicon of the SOI substrate 1 by thermal growth or LPCVD, and the electrically insulating dielectric layer 3 is patterned and engraved. An etch process to retain corresponding pre-prepared resonant oscillator regions 30, pre-prepared test pad regions 31, pre-prepared support beam regions 32, and pre-prepared anchor points The electrically insulating dielectric layer 3 of the region 33, wherein Fig. 3c is a plan view of the process structure formed in the step, and Fig. 3d is a cross-sectional view along the AB side of Fig. 3c.

Specifically, the number of the support beam regions 32 is 1 to 4, respectively, and is preferably 4 in the embodiment, wherein the support beam regions 32 that retain the electrically insulating dielectric layer 3 are respectively 1 to 2 In the present embodiment, there are preferably two; the corresponding anchor point regions 33 are also 1 to 4, respectively, and in the present embodiment, preferably four.

Specifically, the test pad area 31 has two, and each of the test pad areas 31 may be located on the anchor point area 33 having two electrically insulating dielectric layers 3, or may be located in the same one with electrical insulation. On the anchor region 33 of the dielectric layer 3, in the embodiment, it is preferable that the test pad region 31 is located at two opposite angles of the anchor region 33 of the resonant oscillator region 30; the support beam region 32 The end is in contact with the resonant oscillator region 30, and the other end is in contact with the anchor region 33; corresponding to the anchor region 33 having the electrically insulating dielectric layer 3, the support beam region 32 is also There is an electrically insulating dielectric layer 3.

Step 3: As shown in FIG. 3e to FIG. 3f, a metal thin film 4 is formed on the top silicon 12 of the SOI substrate 1 and on the electrically insulating dielectric layer 3 corresponding to the resonant oscillator region 30, or a metal thin film 4 is prepared. The metal thin film 4 is made of gold or aluminum, but is not limited to the two materials. Then, the metal thin film 4 is patterned and etched to form an electrically insulating dielectric layer in the resonant oscillator region 30. A metal coil 40 is formed on the metal coil 40. The metal coil 40 is a spiral metal coil 40 surrounded by the center of the corresponding electrically insulating dielectric layer 3 from the center to the beginning 400. The spiral metal coil 40 has a circular spiral shape. Or a square spiral shape, preferably a square spiral shape in this embodiment; and then in the test pad region 31 having the electrically insulating dielectric layer 3, in the anchor region 33 without the electrically insulating dielectric layer 3 And forming a test pad 310, a metal pad 311, and an electrode pad 5 on the top layer silicon 12 outside the periphery of the resonant oscillator region 30;

Specifically, the number of the electrode pads 5 is 1 to 4, respectively, which is preferably 4 in the embodiment; the number of the test pads 310 is 2. The metal pad 311 is located without the The other anchor region 33 of the test pad 310 is used to apply a fixed potential to the resonant oscillator.

Step 4: As shown in FIG. 3g, a layer of electrically insulating dielectric 3 is deposited again by LPCVD, and is photolithographically and etched to expose the beginning and end of the metal coil 40;

Step 5: As shown in FIG. 3h to FIG. 3j, a second metal thin film 4 is deposited, and the metal thin film 4 is made of gold or aluminum, and is photolithographically and etched to form a metal lead 41. One end of the metal lead 41 is connected to the start end 400 of the first layer metal coil 40, and the other end thereof is connected to the test pad 310 through the support beam region 32, wherein FIG. 3h is a plan view of the process structure formed in the step ( The metal coil 40 in the figure is covered by the electrically insulating dielectric layer 3 except for the beginning 400 and the end 401. For the convenience of illustration, the electrically insulating dielectric layer 3 on the metal coil 40 is not shown, FIG. 3i is A cross-sectional view along the CD direction of Fig. 3h, Fig. 3j is a cross-sectional view taken along line AB of Fig. 3h.

Specifically, the metal lead 41 is a straight line, a curved line, or a broken line. In this embodiment, a straight line is preferably used for drawing the starting end 400 of the metal coil 40.

Step 6: As shown in FIG. 3k to FIG. 31, by performing photolithography and deep reactive ion etching processes on the top layer silicon 12, corresponding to the electrode pad 5, the support beam region 32, and the anchor region 33, respectively The drive electrode 50, the support beam 320, and the anchor point 330 are formed, and the structure of the resonant resonator 6 is released by etching away the SOI substrate 1 under the resonant resonator region 30 by the SiO. The driving electrode 50 is used to drive the resonant vibrator 6 to vibrate. One end of the supporting beam 320 is connected to the resonant vibrator 6 and the other end is fixed to the anchor point 330, so that the resonant vibrator 6 is suspended and fixed on the substrate silicon. 10 above. 3k is a schematic plan view showing the structure of the final resonant resonator 6 (the metal coil 40 in the figure is covered by the electrically insulating dielectric layer 3 except for the beginning 400 and the end 401. For convenience of illustration, no metal is drawn. An electrically insulating dielectric layer 3) on the coil 40, Figure 31 is a cross-sectional view of Figure 3k.

The square spiral metal coil 40 is located on the resonant vibrator 6 and has an electrically insulating dielectric layer 3 between the resonant vibrator 6 for electrically isolating between the resonant vibrator 6 and the metal coil 40, and is distributed. A large amplitude is obtained in the entire plane of the resonant vibrator 6 so that the resonant vibrator 6 vibrates. .

In the present invention, the number of the support beams 320 corresponding to the support beam regions 32 is 1 to 4, respectively, and 4 in the present embodiment, and the number of the anchor points 330 corresponding to the anchor point regions 33 are respectively In the present embodiment, the number of the drive electrodes 50 is 1 to 4, and the number of the drive electrodes 50 corresponding to the electrode pads 5 is 1 to 4, respectively, and is preferably four in the present embodiment.

In the micromechanical sensor prepared by the method of the embodiment, the metal coil adopts a spiral structure, and the size of the induced electromotive force generated by the coil cutting magnetic line is enhanced, and at the same time, the device prepared by the invention operates in the expansion mode. Each point on the resonant oscillator expands or contracts simultaneously with time. For these bulk modal resonators, the resonant frequency is relatively high, so the displacement of each point on the resonant oscillator changes faster with time. If a metal coil is formed on the resonator of the resonator, when the square plate resonator or the circular plate resonator operates in the expansion mode, the metal coil moves with the resonance oscillator. When the device is in a magnetic field, the metal coil cuts the magnetic induction line, thereby generating an induced electromotive force at both ends of the coil. By detecting the magnitude of the induced electromotive force at both ends of the metal coil, the magnitude of the magnetic field strength can be calculated. Since the resonant oscillator of the micromechanical magnetic field sensor proposed by the present invention operates in the expansion mode, each of the metal cutting magnetic lines on the metal coil generates induced electromotive forces which are superimposed on each other, and the intensity of the output signal is enhanced.

In addition, the micro-mechanical magnetic field sensor of the present invention works by using an electrostatic driving device, does not need to pass current on the metal coil, reduces the power consumption of the device, and measures the magnitude of the magnetic field by measuring the induced electromotive force at both ends of the metal coil, driving-detecting The circuit is simple and has little influence on temperature; in the preparation process, it is not necessary to grow or deposit magnetic material on the device, which reduces the complexity of the process; further, the metal coil prepared by the invention may be one or more layers of spiral Coil, It is beneficial to further increase the intensity of the output signal and improve the accuracy of the detection. Embodiment 4

As shown in FIG. 4a, an SOI substrate 1 is provided. A cavity 2 is pre-formed between the top silicon 12 and the buried oxide layer 11 of the SOI substrate 1. The formation process of the cavity 2 is technical in the art. Conventional processes well known to those skilled in the art are: first performing pattern lithography on the substrate silicon 10, and then etching a recess (not shown) deep to the buried oxide layer 11 according to the lithographic pattern, the recess being A square groove, a circular groove, or an annular groove is preferably a square groove in this embodiment. Then, a layer of silicon oxide is thermally grown on the bottom of the groove and the sidewall of the periphery as a buried oxide layer 11, and finally a layer of silicon is bonded as a top layer of silicon 12 on the side having the groove, the top layer of silicon 12 and The cavity between the buried oxide layers 11 is the cavity 2 described.

The main difference between the process of fabricating the device on the SOI substrate 1 of the pre-cavity 2 and the third embodiment is as follows: In the embodiment, the device structure is also released, and the device structure is released. In the first example, after the device structure is fabricated, the structure of the resonant resonator 6 is not released. Therefore, it is necessary to use HF to etch away the SOI substrate buried silicon oxide 11 under the resonant oscillator region 30 to release the device structure. The other process steps are the same as those in the fourth embodiment. The final device structure of this embodiment is shown in Figure 4b. Embodiment 5

The invention also provides a preparation method of the micro-mechanical magnetic field sensor. According to the preparation process in the first embodiment, only the step 3) can be changed into the following steps to prepare the multi-layer series metal coil 40. :

3-1) preparing a metal thin film 4 on the electrically insulating dielectric layer 3 corresponding to the resonant resonator region 30, and patterning and etching the metal thin film 4 to form a metal coil in the resonant oscillator region 30 40;

3-2) depositing an electrically insulating dielectric layer 3 again, and photolithography and etching to expose the beginning and the end of the metal coil 40 (400, 401);

Repeating the processes of steps 3-1) and 3-2) in sequence to prepare a series connection of the multilayer metal coils 40; and in preparing the last layer of the metal coil 40, by photolithography and etching processes The test pad region 31 forms the test pad 310, the metal pad 311 is formed in the anchor region 33 having the electrically insulating dielectric layer 3, and the electrode pad is formed on the top silicon 12 outside the periphery of the resonant resonator region 30. Disk 5.

Specifically, the starting end 400 of the metal coil 40 is located at the center of the resonant vibrator 6, and the metal coil 40 is formed by encircling the inner and outer sides of the spiral coil 40 from the beginning end 400, and the metal coil 40 is vertical. The plurality of spiral metal coils 40 having the same winding direction are mutually connected in series, and each of the spiral metal coils 40 is connected in series by connecting the continuous odd-numbered layer and the even-numbered layer of the starting end 400 of the spiral metal coil 40, and The continuous even and even odd layers of the spiral metal coil end 401 are connected to form a series of multilayer metal coils 40, the spiral The metal coil 40 is a circular spiral or a square spiral. In this embodiment, a square spiral is preferred. Further, the multilayer metal coil may be two layers, or three layers, or multiple layers. It is preferably 2 layers.

The other process steps are the same as those in the first embodiment, and are not described in this embodiment. The final device structure of this embodiment is shown in Fig. 5. Embodiment 6

As shown in FIG. 6a, an SOI substrate 1 is provided. A cavity 2 is pre-formed between the top silicon 12 and the buried oxide layer 11 of the SOI substrate 1. The formation process of the cavity 2 is technical in the art. Conventional processes well known to those skilled in the art are: first performing pattern lithography on the substrate silicon 10, and then etching a recess (not shown) deep to the buried oxide layer 11 according to the lithographic pattern, the recess being A square groove, a circular groove, or an annular groove is preferably a square groove in this embodiment. Then, a layer of silicon oxide is thermally grown on the bottom of the groove and the sidewall of the periphery as a buried oxide layer 11, and finally a layer of silicon is bonded as a top layer of silicon 12 on the side having the groove, the top layer of silicon 12 and The cavity between the buried oxide layers 11 is the cavity 2 described.

The main difference between the process of fabricating the device on the SOI substrate 1 of the pre-cavity 2 and the third embodiment is as follows: In the embodiment, the device structure is also released, and the device structure is released. In the first example, after the device structure is fabricated, the structure of the resonant resonator 6 is not released. Therefore, it is necessary to use HF to etch away the SOI substrate buried silicon oxide 11 under the resonant oscillator region 30 to release the device structure. The other process steps are the same as those in the fourth embodiment. The final device structure of this embodiment is shown in Figure 6b. Example 7

As shown in FIG. 7, the present invention also provides a micro-mechanical magnetic field sensor, comprising:

The SOI substrate 1 has a recess 7 up to its buried oxide layer 11, and is divided into a square groove, a circular groove, or an annular groove according to the opening of the groove 7. In this embodiment, a square groove is preferred. The square groove has two forms, one as shown in Figure 7b and one in Figure 7c.

The resonant resonator 6 is formed by the top silicon 12 of the SOI substrate 1 and is suspended in the recess 7. The shape of the resonant resonator 6 corresponding to the shape of the recess 7 is square, circular, or circular, respectively. In this embodiment, a square shape is preferred; at least one anchor point 330 is located at a corner of the groove 7. In the present invention, the anchor point 330 for fixing the resonant vibrator 6 may be uniformly arranged on the resonant vibrator 6 Four anchors 330 structures of four corners, or two anchor points 330 structures located at diagonal positions of the resonant vibrators 6, or two anchor points 330 structures located adjacent to the two corners of the resonant vibrator 6, in this embodiment A four anchor 330 structure is preferred.

The support beam 320 is connected to the resonant vibrator 6 at the other end, and the other end is connected to the anchor point 330 to support the resonant vibrator to be suspended in the recess 7. In the present invention, the support beam 320 corresponds to the anchor point 330. Can be evenly arranged in the resonance Four support beams 320 of four corners of the vibrator 6 , or two support beams 320 located at diagonal positions of the resonant vibrator 6 , or two support beams 320 located at two adjacent corners of the resonant vibrator 6 Preferred in the embodiment is a structure of four support beams 320;

Two test pads 310 are formed on the anchor point 330, and each of the test pads 310 is insulated from each other. Specifically, the two test pads 310 may be located at the same anchor point 330, or respectively located at two The anchor points 330 are preferably located in the two anchor points 330 respectively in the embodiment; a plurality of metal pads 311 are located on the anchor points not having the test pads, and are used for the resonant oscillators. A fixed potential is applied. In this embodiment, the other two anchor points respectively have a metal pad 311.

The metal coil 40 is formed on the resonant vibrator 6. Specifically, the metal coil 40 is a circular or square metal coil 40 that surrounds the periphery of the resonant vibrator 6 , and both ends of the metal coil 40 pass through one. Or two of the support beams 320 are respectively connected to the two test pads 310. In the embodiment, the two ends of the metal coil 40 are respectively connected to the two test pads 310 through two support beams 320. More specifically, the metal coil 40 is made of gold or aluminum.

The driving electrode 50 is located on the top layer of silicon 12 outside the periphery of the resonant resonator 6 for driving the resonant resonator 6 to vibrate. Specifically, the number of the driving electrodes 50 is 1 to 4, which is preferably in the embodiment. 4. Example eight

As shown in FIG. 8, the present invention also provides a micro-mechanical magnetic field sensor. The structure of the microstructured magnetic field sensor is different from that of the seventh embodiment except that the structure of the metal coil 40 is the same, and the other components are not described herein. Therefore, only the structure of the microstructured magnetic field sensor metal coil 40 is given in the present embodiment as follows:

a metal coil 40 is formed on the resonant resonator 6. Specifically, a starting end of the metal coil 40 is located at a center of the resonant oscillator 6, and the metal coil 6 is formed with a circular shape from the inner and outer sides around the starting end 400. The spiral or square spiral metal coil 40 is preferably a square spiral metal coil 40 in this embodiment. Example nine

As shown in FIG. 9, the present invention also provides a micro-mechanical magnetic field sensor. The structure of the microstructured magnetic field sensor is different from that of the seventh embodiment except that the structure of the metal coil 40 is the same, and the other components are not described herein. Therefore, only the structure of the microstructured magnetic field sensor metal coil 40 is given in the present embodiment as follows:

a metal coil 40 is formed on the resonant vibrator 6 , a starting end 400 of the metal coil 40 is at the center of the resonant vibrator 6 , and the metal coil 6 is formed with a circular spiral from the inner and outer sides around the starting end 400 . Or square spiral metal coil 40; specifically, the metal coil 40 is vertically wound by a plurality of spiral metal wires having the same winding direction The coils 40 are formed in series with each other, and each of the spiral metal coils 40 is connected in series by connecting a continuous odd-numbered layer and an even-numbered layer of the starting end 400 of the spiral metal coil 40, and a continuous even-numbered layer and an odd-numbered layer of the spiral metal. The ends 401 of the coils 40 are connected to form a plurality of metal coils 40 connected in series, and each of the spiral metal coils 40 connected in series has an electrically insulating dielectric layer 3 in addition to the joint. Specifically, the spiral metal coil 40 has a circular spiral shape or a square spiral shape, and is preferably a square spiral shape in the embodiment. Further, the multilayer metal coil 40 may be two layers or three layers. Or more layers, preferably two layers in this embodiment. The multi-layered spiral coil 40 is advantageous for further increasing the intensity of the output signal and improving the accuracy of the detection.

In summary, the micro-mechanical magnetic field sensor proposed by the invention uses electrostatic driving to excite the resonant vibrator to enter a resonant state, and the metal coil is located above the resonant vibrator. When the sensor is in the magnetic field, the resonant vibrator will drive the metal coil to move, the metal coil The magnetic induction line is cut to generate an induced electromotive force at both ends of the coil. Meanwhile, the resonant oscillator of the micromechanical magnetic field sensor proposed by the present invention operates in an expanded mode, and thus the induced electromotive force generated by each small piece of metal cutting magnetic line on the metal coil is superimposed on each other. The strength of the output signal is enhanced.

In addition, the micro-mechanical magnetic field sensor of the present invention works by using an electrostatic driving device, does not need to pass current on the metal coil, reduces the power consumption of the device, and measures the magnitude of the magnetic field by measuring the induced electromotive force at both ends of the metal coil, driving-detecting The circuit is simple and has little influence on temperature; in the preparation process, it is not necessary to grow or deposit magnetic materials on the device, which reduces the complexity of the process; and the metal coil prepared by the invention can be one or more layers of spiral coils. It is beneficial to further increase the intensity of the output signal and improve the accuracy of the detection. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

Those skilled in the art can also use the above method to prepare a micromechanical magnetic field sensor having a plurality of resonant oscillator structures according to different practical applications or requirements. For example, when two resonant resonator structures are included in the micromechanical magnetic field sensor, those skilled in the art can separately prepare two resonant oscillator structures according to the same manufacturing process as the above method, and adjust the multiple layers according to actual conditions. Parameters such as the direction, series, shape and number of layers of the metal coil. Of course, those skilled in the art will also appreciate that the method of the present invention can also be used to prepare a micromechanical magnetic field sensor having more than two resonant oscillator structures, and the above embodiments merely exemplify the principles and effects of the present invention. It is not intended to limit the invention. Modifications or variations of the above-described embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and scope of the invention are intended to be covered by the appended claims.

Claims

The invention provides a method for preparing a micromechanical magnetic field sensor, which comprises at least:

1) providing an SOI substrate;

4) removing a portion of the top silicon by photolithography and deep reactive ion etching, forming drive electrodes, support beams, and anchor points corresponding to the electrode pads, the support beam regions, and the anchor regions, respectively, and then utilizing hydrofluoric acid The SOI substrate buried oxide layer below the resonant resonator region is etched away to release the device structure to form a resonant oscillator. The method for fabricating a micromechanical magnetic field sensor according to claim 1, wherein a cavity corresponding to the resonant oscillator region is pre-defined between the buried oxide layer of the SOI substrate and the top silicon in step 1) In the case of the body, the step 4) includes:

Partial top silicon is removed by photolithography and deep reactive ion etching, and driving electrodes, support beams, and anchor points are respectively formed in the electrode pads, the support beam regions, and the anchor regions, and the device structure is released to form a resonance. Vibrator. The method of manufacturing a micro-mechanical magnetic field sensor according to claim 1 or 2, wherein when a metal coil is prepared on the electrically insulating dielectric layer corresponding to the resonant resonator region, the step 3) further includes:

Forming a metal thin film on the top silicon of the SOI substrate and the electrically insulating dielectric layer corresponding to the resonant oscillator region, and forming a metal coil in the resonant oscillator region by patterning and etching the metal thin film respectively Forming a test pad in the test pad region, forming a metal pad in a portion of the anchor region, and forming an electrode pad on the top silicon outside the periphery of the resonant oscillator region. The method of manufacturing a micromechanical magnetic field sensor according to claim 3, wherein: the metal coil is a circular or square coil around a circumference of the electrically insulating dielectric layer, and the first and last two ends of the coil End through the branch A beam is attached to the two test pads. The method of manufacturing a micro-mechanical magnetic field sensor according to claim 1 or 2, wherein when a metal coil is prepared on the electrically insulating dielectric layer corresponding to the resonant resonator region, the step 3) further includes:

3-2) depositing a layer of electrically insulating dielectric again, and photolithography and etching to expose the beginning and the end of the metal coil;

3-3) depositing a second metal thin film, and performing photolithography and etching to form a metal lead, and the beginning of the metal lead is connected to the beginning of the first metal coil, and the end is connected by a support beam Go to the test pad. The method of manufacturing a micromechanical magnetic field sensor according to claim 5, wherein: the metal coil is a spiral metal coil surrounded by an inner and outer circumference of the center of the corresponding electrically insulating dielectric layer, the end of which is Connected to the test pad by the support beam. The micromachined magnetic field sensor according to claim 6, wherein the spiral metal coil has a circular spiral shape or a square spiral shape. The method of manufacturing a micromechanical magnetic field sensor according to claim 5, wherein the metal lead is a straight line, a curved line, or a broken line, and the metal lead is made of gold or aluminum. The method of manufacturing the micro-mechanical magnetic field sensor according to claim 1 or 2, wherein, when the multi-layer metal coil is on the electrically insulating medium layer corresponding to the region of the vibrator, the step 3) further comprises:

Repeating the processes of steps 3-1) and 3-2) in sequence to prepare a series connection of a plurality of metal coils; and in preparing the metal coil of the last layer, respectively, by the photolithography and etching processes in the test The pad area forms a test pad, A metal pad is formed in a portion of the anchor region, and an electrode pad is formed on top silicon outside the periphery of the resonant resonator region. The method of manufacturing a micromechanical magnetic field sensor according to claim 9, wherein: the metal coil is a spiral metal coil surrounded by an inner and outer circumference of the center of the corresponding electrically insulating dielectric layer, the end of which is Connected to the test pad by the support beam. The micromachined magnetic field sensor according to claim 10, wherein the spiral metal coil has a circular spiral shape or a square spiral shape. The method of manufacturing a micromechanical magnetic field sensor according to claim 9, wherein: the serial connection mode of the multi-layer metal coil is continuous, the odd-numbered and the even-numbered metal coils are connected through the beginning end, and the continuous even number And the odd number of said metal coils are connected by ends, and each of the metal coils has the same winding direction and shape. The method of manufacturing a micromechanical magnetic field sensor according to claim 1 or 2, wherein: one end of the support beam is connected to the resonant vibrator, and the other end is connected to the anchor point to fix the resonant vibrator. The method of fabricating a micromechanical magnetic field sensor according to claim 1 or 2, wherein: the test pad is located on an anchor point having the electrically insulating dielectric layer, and the metal pad is located not having the The anchor point of the electrically insulating dielectric layer. The method of manufacturing a micromachined magnetic field sensor according to claim 1 or 2, wherein the metal coil is made of gold or aluminum. The method of manufacturing a micromechanical magnetic field sensor according to claim 1 or 2, wherein: the plurality of metal coils have an electrically insulating dielectric layer in addition to the joint. A micromechanical magnetic field sensor, characterized in that it comprises at least:

a SOI substrate having a recess having a depth up to its buried oxide layer;

At least one anchor point located on a side of the groove;

a resonant oscillator formed by top silicon of the SOI substrate and suspended in the recess; a support beam having one end connected to the resonant vibrator and the other end connected to the anchor point to support the resonant vibrator to hang in the recess;

a metal coil formed on the resonant oscillator;

Two test pads are formed on the anchor point, respectively connected to the beginning and the end of the metal coil, and each of the test pads is insulated from each other;

a plurality of metal pads formed on a portion of the anchor point for applying a fixed potential to the resonant oscillator; a driving electrode on the top silicon outside the periphery of the resonant oscillator for driving the resonant oscillator . The micromachined magnetic field sensor according to claim 17, wherein an insulating dielectric layer is provided between the metal coil and the resonant resonator. The micromechanical magnetic field sensor according to claim 17, wherein the metal coil is made of gold or aluminum. The micromechanical magnetic field sensor according to claim 17, wherein: the metal coil is a circular or square metal coil around a circumference of the resonant oscillator, and the beginning and the end of the metal coil pass through the support The beams connect the two test pads, respectively. The micromechanical magnetic field sensor according to claim 17, wherein: the metal coil is a spiral metal coil surrounded by the center of the resonant resonator from the inside to the outside, and the beginning and the end thereof are connected by the support beam. Go to the test pad. The micromechanical magnetic field sensor according to claim 21, wherein the spiral metal coil has a circular spiral shape or a square spiral shape. The micromechanical magnetic field sensor according to claim 21, wherein the metal coil is composed of a plurality of the spiral metal coils connected in series, and each of the spiral metal coils has the same winding direction. The micromechanical magnetic field sensor according to claim 23, wherein: said spiral metal coils are connected in series by consecutive odd-numbered and even-numbered spiral metal coils, and continuous even-numbered with The ends of the odd-numbered spiral metal coils are connected, and each of the spiral metal coils connected in series has an electrically insulating dielectric layer except for the joint. The micromechanical magnetic field sensor according to claim 17, wherein the groove is a square groove, a circular groove, or an annular groove, and the resonant oscillator has a square structure and a circular shape. Structure, or ring structure.