A low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor

Abstract

The application discloses a low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor, which comprises, from bottom to top, an insulating base, a bottom magnetic film, a combined coil and a top magnetic film; insulating isolation layers are arranged between the combined coil and the bottom magnetic film and the top magnetic film; the bottom magnetic film and the top magnetic film are rectangular planar magnetic films or surface strip grid pattern magnetic films; at least one of the bottom magnetic film and the top magnetic film is a surface strip grid pattern magnetic film; and the combined coil is a double helix coil structure, comprising alternating excitation coils and induction coils. The application not only weakens the demagnetization effect of the surface strip grid pattern magnetic film in the length direction, enhances the effective permeability of the surface strip grid pattern magnetic film in the length direction, but also suppresses eddy current noise, so that low-noise high-sensitivity magnetic field detection is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic sensor, in particular to a low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor. BACKGROUND

[0002] The magnetic sensor refers to a sensor that uses a magnetic sensitive element to perceive a physical quantity related to a magnetic signal and converts it into an electric signal. It is widely used in target detection, flow monitoring, navigation positioning and biomedical fields. It has promoted the rapid development of atmospheric science, environmental monitoring, resource exploitation, underwater navigation and disease diagnosis.

[0003] In the era of intelligent sensing, the demand for high-sensitivity micro magnetic field sensors is increasing in emerging industries such as artificial intelligence, new energy vehicles, robots and intelligent health detection, in order to realize weak magnetic field detection.

[0004] At present, the Hall sensor has low sensitivity; the superconducting quantum interference effect sensor has large volume, complicated operation and high cost; the anisotropic magnetoresistance sensor has problems such as offset and hysteresis; the fluxgate sensor has a complex structure and is difficult to realize miniaturization. On the contrary, the planar laminated magnetic induction type magnetic sensor is composed of a planar coil and a magnetic thin film. It relies on the magnetic properties of the effective permeability of the magnetic thin film changing with the external magnetic field. The structure is simple, easy to be compatible with micro-electro-mechanical system (MEMS) technology, and is particularly suitable for preparing micro sensors.

[0005] However, once the magnetic material is made into a planar thin film with a certain shape, a closed magnetic circuit cannot be formed inside it. The demagnetization effect causes the effective permeability of the magnetic thin film to be much smaller than the nominal permeability of the magnetic material, greatly limiting the improvement of the sensor sensitivity. One of the effective methods to improve the sensitivity is to compensate for the shape demagnetization and improve the effective permeability of the magnetic thin film.

[0006] In addition, for the magnetic sensor using magnetic sensitive material, the magnetic noise of the magnetic material when magnetized is the main source of sensor noise. For the planar laminated magnetic induction type magnetic sensor, the magnetic noise is mainly caused by eddy current. Suppressing eddy current can effectively reduce the magnetic noise.

[0007] Prior art, the publication number: CN 114899000 A discloses a magnetic flux gate sensor core and its preparation method, wherein the core is composed of multiple layers of strip-shaped cores, the cross-sectional area of a single strip-shaped core is reduced, so that the shape demagnetization effect of a single core is weakened, and the effective permeability of a single core is improved. In this way, the sensitivity of the sensor is improved while ensuring that the total effective cross-sectional area of the core remains unchanged. However, the multiple layers of strip-shaped cores require at least 7 steps of micro-processing technology, which is complex and has a low success rate, and is not suitable for planar laminated micro magnetic sensors. The publication number: CN 107907145 A discloses a low-noise planar magnetic sensor, which processes multiple slits in the planar magnetic film, and the length direction of the slits intersects the current direction flowing through the corresponding slits of the planar coil. In this way, the resistance of the eddy current loop in the magnetic film is greatly increased, so that the Joule heat power generated by the eddy current is very low, greatly reducing the eddy current loss and eddy current noise. However, the structure of multiple slits intensifies the magnetic leakage, weakens the electromagnetic coupling between the planar coil and the magnetic film, and greatly reduces the sensitivity of the sensor.

[0008] How to compensate for shape demagnetization to improve the effective permeability of the magnetic film while suppressing eddy current magnetic noise is still a problem to be solved in the field. SUMMARY

[0009] 1. The technical problem to be solved:

[0010] To solve the above technical problems, the present application provides a low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor.

[0011] 2. Technical solution:

[0012] A low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor, the magnetic sensor is sequentially arranged from bottom to top as an insulating substrate, a bottom magnetic film, a combination coil and a top magnetic film; an insulating isolation layer is arranged between the combination coil and the bottom magnetic film and the top magnetic film; the bottom magnetic film and the top magnetic film are rectangular planar magnetic films or surface strip grid pattern magnetic films; and at least one of the bottom magnetic film and the top magnetic film is a surface strip grid pattern magnetic film; the combination coil is a double helix coil structure, including an excitation coil and an induction coil arranged alternately, the excitation coil and the induction coil are both planar rectangular spiral structures; the combination coil and the surface strip grid pattern magnetic film are arranged vertically intersected.

[0013] The surface strip grid pattern magnetic film comprises a surface smooth magnetic film and a plurality of strip grid pattern magnetic films; the plurality of strip grid pattern magnetic films are arranged at equal intervals on the surface smooth magnetic film; the surface smooth magnetic film and the single strip grid pattern magnetic film are both rectangular; the long side of the strip grid pattern magnetic film is perpendicular to the long side of the surface smooth magnetic film; the length-width ratio of the single strip grid pattern magnetic film is not less than ten; the length of the strip grid pattern magnetic film is the same as the width of the surface smooth magnetic film; the surface smooth magnetic film is located on one side of the combined coil; both ends of the excitation coil and the induction coil are provided with electrodes, one of the electrodes of the excitation coil is the input end of the electric excitation signal, and the other electrode is the output end of the electric excitation signal; the potential difference between the two electrodes of the induction coil is the output signal.

[0014] Further, the substrate is a silicon substrate, a quartz glass substrate or an alumina substrate.

[0015] Further, the material of the excitation coil and the induction coil is copper.

[0016] Further, the combined coil is provided with one or more, and the excitation coils of the plurality of combined coils are electrically connected; the induction coils of the plurality of combined coils are electrically connected.

[0017] Further, the material of the insulating isolation layer is silicon nitride or polyimide.

[0018] Further, the low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor is prepared by a micro processing process.

[0019] It should be noted that the electrodes of the excitation coil and the induction coil are located on the side of the top magnetic film or the bottom of the top magnetic film; when the electrodes are located at the bottom of the top magnetic film, corresponding holes are opened on the top magnetic film to expose the position of the electrodes.

[0020] 3. Beneficial effects:

[0021] The surface strip grid pattern magnetic film is used as a magnetic sensitive element in the application, and the shape demagnetization can be compensated by the strip grid pattern magnetic film to improve the effective permeability of the surface smooth magnetic film and the sensitivity of the sensor. Compared with the planar magnetic film (the shape is the same as that of the surface smooth magnetic film) with the same thickness, the effective permeability of the surface strip grid pattern magnetic film is obviously enhanced, and the physical explanation is as follows:

[0022] (1) For the planar magnetic film made of a magnetic material, under the condition that the thickness is much smaller than the length and the width, the demagnetization factor of the planar magnetic film along the length direction is approximately inversely proportional to the thickness. The thickness of the surface smooth magnetic film of the surface strip grid pattern magnetic film is reduced, and correspondingly, the demagnetization factor and the demagnetization field along the length direction in the region are reduced.

[0023] (ii) When a surface-patterned magnetic film with a striped magnetic film is magnetized along its length by an external magnetic field, surface magnetic charges exist on both the end faces of the short and long sides of the surface-patterned magnetic film. The magnetic polarization field originates from the end face of the positive magnetic charge and terminates at the end face of the negative magnetic charge. Therefore, in the regions of the surface-patterned magnetic film without a striped magnetic film, the direction of the magnetic polarization field is the same as the direction of the external magnetic field. In addition, since the aspect ratio of a single striped magnetic film is not less than 10, and the spacing between adjacent striped magnetic films is less than the length of the surface-patterned magnetic film, the magnetic polarization field generated by the long side end face of the striped magnetic film is greater than the demagnetizing field generated by the short side end face of the surface-patterned magnetic film. Therefore, the magnetic polarization field can not only cancel the demagnetizing field but also significantly enhance the effective field in the regions without a striped magnetic film. Processing strip patterns on the surface of a smooth magnetic thin film can not only compensate for the shape demagnetization field, but also further enhance the effective field of the surface strip pattern magnetic thin film by utilizing the magnetic polarization field. This will significantly improve the effective permeability of the smooth magnetic thin film, thereby achieving the goal of improving the sensor sensitivity.

[0024] Furthermore, in the region without the magnetic thin film with the grid pattern, the film thickness decreases, the resistance increases, and the effective permeability of the region increases significantly. Therefore, the eddy current loss generated by the excitation coil is significantly reduced, resulting in a reduction in the eddy current noise of the sensor.

[0025] Therefore, this invention not only weakens the demagnetization effect along the length of the surface strip pattern magnetic film and enhances the effective permeability along the length of the surface strip pattern magnetic film, but also suppresses eddy current noise, thereby achieving low-noise and high-sensitivity magnetic field detection. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the low-noise, high-sensitivity miniature planar stacked magnetic induction sensor of Embodiment 1 of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the magnetic thin film with surface stripe pattern in Embodiment 1 of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of the induction coil 4 in Embodiment 1 of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of the low-noise, high-sensitivity miniature planar stacked magnetic induction sensor of Embodiment 2 of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of the low-noise, high-sensitivity miniature planar stacked magnetic induction sensor of Embodiment 3 of the present invention;

[0031] Figure 6 This is a schematic diagram of the excitation coil structure of Embodiment 3 of the present invention;

[0032] Figure 7 This is a schematic diagram of the structure of the low-noise, high-sensitivity miniature planar stacked magnetic induction sensor of Embodiment 4 of the present invention;

[0033] Figure 8 This is a top view of the low-noise, high-sensitivity miniature planar stacked magnetic induction sensor of Embodiment 4 of the present invention;

[0034] Figure 9 These are sensitivity data graphs of sensors prepared from smooth magnetic thin films and magnetic thin films with surface stripe patterns, respectively, according to Embodiment 5 of the present invention. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings.

[0036] like Figures 1-8 As shown, a low-noise, high-sensitivity miniature planar stacked magnetic induction sensor is disclosed. From bottom to top, the sensor comprises an insulating substrate 1, a bottom magnetic film 2, a combined coil, and a top magnetic film 5. Insulating layers are provided between the combined coil, the bottom magnetic film 2, and the top magnetic film 5. The bottom magnetic film 2 and the top magnetic film 5 are rectangular planar magnetic films or surface stripe patterned magnetic films. At least one of the bottom magnetic film 2 and the top magnetic film 5 is a surface stripe patterned magnetic film. The combined coil has a double-helix coil structure, including alternately arranged excitation coils 3 and induction coils 4, both of which are planar rectangular helical structures. The combined coil and the surface stripe patterned magnetic film are arranged perpendicularly.

[0037] The surface striped magnetic film includes a smooth magnetic film 6 and multiple striped magnetic films 7; the multiple striped magnetic films 7 are arranged at equal intervals on the smooth magnetic film 6; both the smooth magnetic film 6 and the individual striped magnetic films 7 are rectangular; the long side of the striped magnetic film 7 is perpendicular to the long side of the smooth magnetic film 6; the aspect ratio of the individual striped magnetic film 7 is not less than 10; the length of the striped magnetic film 7 is the same as the width of the smooth magnetic film 6; the smooth magnetic film 6 is located on one side of the combined coil; electrodes are provided at both ends of the excitation coil 3 and the induction coil 4, one electrode of the excitation coil 3 is the input end of the electrical excitation signal, and the other electrode is the output end of the electrical excitation signal; the potential difference between the two electrodes of the induction coil 4 is the output signal.

[0038] Substrate 1 is a silicon substrate, a quartz glass substrate, or an alumina substrate.

[0039] Both the excitation coil 3 and the induction coil 4 are made of copper.

[0040] The combined coil has one or more excitation coils 3 electrically connected to each other; the combined coil has multiple induction coils 4 electrically connected to each other.

[0041] The insulating layer material is silicon nitride or polyimide.

[0042] The low-noise, high-sensitivity miniature planar stacked magnetic induction sensor is fabricated using microfabrication technology.

[0043] It should be noted that the electrodes of the excitation coil 3 and the induction coil 4 are located on the side or bottom of the top magnetic film 5; when the electrodes are located at the bottom of the top magnetic film 5, corresponding openings are made on the top magnetic film 5 to expose the position of the electrodes.

[0044] Example 1

[0045] like Figures 1-3 As shown, the low-noise, high-sensitivity miniature planar stacked magnetic induction sensor of this embodiment comprises, from bottom to top, an insulating substrate 1, a bottom magnetic film 2, a single combined coil, and a top magnetic film 5; an insulating isolation layer (not shown in the figure) is provided between the combined coil, the bottom magnetic film 2, and the top magnetic film 5; both the bottom magnetic film 2 and the top magnetic film 5 are surface stripe patterned magnetic films; the combined coil has a double helix coil structure, including alternately arranged excitation coils 3 and induction coils 4, both of which are planar rectangular helical structures; the combined coil and the surface stripe patterned magnetic film are arranged perpendicularly to each other;

[0046] The surface striped magnetic film includes a smooth magnetic film 6 and multiple striped magnetic films 7; the multiple striped magnetic films 7 are arranged at equal intervals on the smooth magnetic film 6; both the smooth magnetic film 6 and the individual striped magnetic films 7 are rectangular; the long side of the striped magnetic film 7 is perpendicular to the long side of the smooth magnetic film 6; the aspect ratio of the individual striped magnetic film 7 is not less than 10; the length of the striped magnetic film 7 is the same as the width of the smooth magnetic film 6; the smooth magnetic film 6 is located on one side of the combined coil; electrodes are provided at both ends of the excitation coil 3 and the induction coil 4, one electrode of the excitation coil 3 is the input end of the electrical excitation signal, and the other electrode is the output end of the electrical excitation signal; the potential difference between the two electrodes of the induction coil 4 is the output signal.

[0047] The electrodes on the outside of the excitation coil 3 and the induction coil 4 are located on the outside of the top magnetic film 5, and the electrodes on the inside of the excitation coil 3 and the induction coil 4 are located on the inside of the top magnetic film 5.

[0048] Example 2

[0049] likeFigure 4 As shown in the drawings, the low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor of the embodiment comprises, from bottom to top, an insulating substrate 1, a bottom magnetic thin film 2, two combined coils, and a top magnetic thin film 5. An insulating isolation layer (not shown in the drawings) is arranged between the combined coils and the bottom magnetic thin film 2 and the top magnetic thin film 5. The bottom magnetic thin film 2 is a planar magnetic thin film. The top magnetic thin film 5 is a surface strip grid pattern magnetic thin film. The combined coils are double helix coil structures, comprising an excitation coil 3 and an induction coil 4 arranged alternately. The excitation coil 3 and the induction coil 4 are both planar rectangular helix structures. The combined coils and the surface strip grid pattern magnetic thin film are arranged in vertical intersection.

[0050] The surface strip grid pattern magnetic thin film comprises a surface smooth magnetic thin film 6 and a plurality of strip grid pattern magnetic thin films 7. The plurality of strip grid pattern magnetic thin films 7 are arranged at equal intervals on the surface smooth magnetic thin film 6. The surface smooth magnetic thin film 6 and the single strip grid pattern magnetic thin film 7 are both rectangular. The long side of the strip grid pattern magnetic thin film 7 is perpendicular to the long side of the surface smooth magnetic thin film 6. The length-width ratio of the single strip grid pattern magnetic thin film 7 is not less than ten. The length of the strip grid pattern magnetic thin film 7 is the same as the width of the surface smooth magnetic thin film 6. The surface smooth magnetic thin film 6 is located on one side of the combined coils. Both ends of the excitation coil 3 and the induction coil 4 are provided with electrodes. One of the electrodes of the excitation coil 3 is an input end of an electric excitation signal, and the other electrode is an output end of the electric excitation signal. The potential difference between the two electrodes of the induction coil 4 is an output signal.

[0051] The electrodes on the outer side of the excitation coil 3 and the induction coil 4 are located on the side of the top magnetic thin film 5, and the electrodes on the inner side of the excitation coil 3 and the induction coil 4 are located on the bottom of the top magnetic thin film 5. The top magnetic thin film 5 is provided with an opening to expose the positions of the two inner electrodes. The electrodes on the inner side of the two excitation coils 3 are electrically connected. The electrodes on the inner side of the two induction coils 4 are electrically connected.

[0052] The low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor of the embodiment is prepared by a micro processing technology, comprising the following steps:

[0053] S1: Select a silicon substrate as a substrate, use a magnetron sputtering device to sputter a titanium (Ti) 10 nm adhesion layer on the silicon substrate, then continue to sputter a soft magnetic material to form a bottom magnetic thin film (a planar magnetic thin film), with a thickness of 500 nm, and finally sputter 20 nm of titanium as a protective layer to prevent the soft magnetic material from being oxidized. The titanium can also be used as an adhesion layer for the next process,

[0054] S2: Use a plasma enhanced chemical vapor deposition system to deposit a first layer of silicon nitride (Si3N4) 550 nm and prepare for processing of the combined coils.

[0055] The first photoresist is spin-coated on the first layer of silicon nitride at a speed of 1500 r / min by using a spin coater, the thickness of the first photoresist is 6 μm, then the first photoresist is baked on an electric hot plate at 90 ℃ for 120 seconds, then the first photoresist plate with the shape of the combined coil is exposed by using a photoetching machine, and developed in a developing solution for 45 seconds, then rinsed with deionized water for 35 seconds, to obtain the pattern of the combined coil;

[0056] The first layer of silicon nitride is etched by 450 nm by using a reactive ion etching system, and the remaining 100 nm thick first layer of silicon nitride is used as an insulating isolation layer above the bottom magnetic thin film, to electrically isolate the bottom magnetic thin film and the combined coil;

[0057] S3: A metal titanium (Ti) adhesion layer of 20 nm is sputtered on the first layer of silicon nitride by using a magnetron sputtering device, then a metal copper (Cu) of 400 nm is sputtered to form the combined coil, and finally a metal titanium (Ti) protective layer of 30 nm is sputtered to prevent the oxidation of the metal copper caused by the subsequent photoresist stripping process, and to serve as an adhesion layer for subsequent processes; the first photoresist is stripped by using acetone, and the sample surface is cleaned by using deionized water for 15 seconds, and finally dried by using dry nitrogen gas;

[0058] S4: A second layer of silicon nitride of 1300 nm is deposited on the combined coil by using a plasma enhanced chemical vapor deposition system, to prepare a smooth surface magnetic thin film for processing a rectangular pattern;

[0059] The second photoresist is spin-coated on the second layer of silicon nitride at a speed of 1500 r / min by using a spin coater, the thickness of the second photoresist is 6 μm, then the second photoresist is baked on an electric hot plate at 90 ℃ for 120 seconds, then the second photoresist plate with a 2 mm x 6 mm rectangular pattern (the size of the smooth surface magnetic thin film) is exposed by using a photoetching machine, and developed in a developing solution for 45 seconds, then rinsed with deionized water for 35 seconds, to obtain the rectangular pattern;

[0060] The second layer of silicon nitride is etched by 850 nm by using a reactive ion etching system, and the remaining 450 nm of the second layer of silicon nitride is used as an insulating isolation layer above the combined coil; the top magnetic thin film and the combined coil are electrically isolated;

[0061] A metal titanium (Ti) adhesion layer of 20 nm is sputtered on the second layer of silicon nitride by using a magnetron sputtering device, then a soft magnetic material of 250 nm is sputtered as a smooth surface magnetic thin film;

[0062] S5: A third silicon nitride of 580 nm is deposited at low temperature by using an inductively coupled plasma chemical vapor deposition system, since the sample surface still has a photoresist at present, the deposition of the third silicon nitride by using a plasma enhanced chemical vapor deposition system will cause the photoresist to melt due to the high temperature, therefore, the third silicon nitride can only be deposited at low temperature.

[0063] The second photoresist is stripped with acetone and ultrasonically cleaned with deionized water for 15 seconds, and finally the sample surface is blown dry with dry nitrogen;

[0064] The third photoresist is spin-coated on the third silicon nitride at a speed of 1500 r / min by using a spin coater, and the thickness of the third photoresist is 6 μm. Then the third photoresist is baked on an electric hot plate at 90 °C for 120 seconds. Subsequently, the third photoresist plate with a 20 μm wide strip grating pattern magnetic film shape is exposed by using a photoetching machine, and developed in a developing solution for 45 seconds. Then the sample is rinsed with deionized water for 35 seconds to obtain the shape of the strip grating pattern magnetic film, which is prepared for processing the strip grating pattern magnetic film.

[0065] The third silicon nitride is etched by 580 nm using a reactive ion etching system.

[0066] A soft magnetic material is sputtered 250 nm as the strip grating pattern magnetic film by using a magnetron sputtering, and then a titanium (Ti) adhesion layer is continuously sputtered 30 nm.

[0067] S6: A fourth silicon nitride is deposited 310 nm at low temperature by using an inductively coupled plasma chemical vapor deposition system. This step is designed to prevent the strip grating pattern magnetic film from falling off during the subsequent stripping.

[0068] The third photoresist is stripped with acetone and ultrasonically cleaned with deionized water for 15 seconds, and finally the sample surface is blown dry with dry nitrogen.

[0069] The fourth photoresist is spin-coated on the fourth silicon nitride at a speed of 1500 r / min by using a spin coater, and the thickness of the fourth photoresist is 6 μm. Then the fourth photoresist is baked on an electric hot plate at 90 °C for 120 seconds. Subsequently, the fourth photoresist plate with a hole pattern is exposed by using a photoetching machine, and developed in a developing solution for 45 seconds. Then the sample is rinsed with deionized water for 35 seconds to obtain the hole pattern. The fourth silicon nitride is etched by 1280 nm using a reactive ion etching system, so that the silicon nitride on the electrode is completely etched to obtain the hole.

[0070] A chromium layer 50 nm is first evaporated on the surface of the electrode by using an electron beam evaporation coating device, and then a gold layer 250 nm is evaporated. The combination of chromium and gold is selected to improve the adhesion of gold.

[0071] The fourth photoresist is stripped with acetone and ultrasonically cleaned with deionized water for 15 seconds, and finally the sample surface is blown dry with dry nitrogen. The electrode electrical connection inside the two excitation coils 3 and the electrode electrical connection inside the two induction coils 4 are realized by the subsequent flying wire process.

[0072] Example 3

[0073] AsFigures 5-6 As shown, the low-noise, high-sensitivity miniature planar stacked magnetic induction sensor of this embodiment comprises, from bottom to top, an insulating substrate 1, a bottom magnetic film 2, two combined coils, and a top magnetic film 5; an insulating isolation layer (not shown in the figure) is provided between the combined coils, the bottom magnetic film 2, and the top magnetic film 5; the bottom magnetic film 2 is a planar magnetic film; the top magnetic film 5 is a surface stripe pattern magnetic film; the combined coils have a double helix coil structure, including alternately arranged excitation coils 3 and induction coils 4, both of which are planar rectangular helical structures; the combined coils and the surface stripe pattern magnetic film are arranged perpendicularly.

[0074] The surface striped magnetic film includes a smooth magnetic film 6 and multiple striped magnetic films 7; the multiple striped magnetic films 7 are arranged at equal intervals on the smooth magnetic film 6; both the smooth magnetic film 6 and the individual striped magnetic films 7 are rectangular; the long side of the striped magnetic film 7 is perpendicular to the long side of the smooth magnetic film 6; the aspect ratio of the individual striped magnetic film 7 is not less than 10; the length of the striped magnetic film 7 is the same as the width of the smooth magnetic film 6; the smooth magnetic film 6 is located on one side of the combined coil; electrodes are provided at both ends of the excitation coil 3 and the induction coil 4, one electrode of the excitation coil 3 is the input end of the electrical excitation signal, and the other electrode is the output end of the electrical excitation signal; the potential difference between the two electrodes of the induction coil 4 is the output signal.

[0075] The two electrodes of the two excitation coils 3 are located on the front side of the top magnetic film; the two electrodes of the two induction coils 4 are located on the rear side of the top magnetic film; the electrodes inside the two excitation coils 3 are electrically connected; the electrodes inside the two induction coils 4 are electrically connected.

[0076] Example 4

[0077] like Figures 7-8 As shown, the low-noise, high-sensitivity miniature planar stacked magnetic induction sensor of this embodiment comprises, from bottom to top, an insulating substrate 1, a bottom magnetic film 2, two combined coils, and a top magnetic film 5; an insulating isolation layer (not shown in the figure) is provided between the combined coils, the bottom magnetic film 2, and the top magnetic film 5; both the bottom magnetic film 2 and the top magnetic film 5 are surface stripe patterned magnetic films; the combined coils have a double helix coil structure, including alternately arranged excitation coils 3 and induction coils 4, both of which are planar rectangular helical structures; the combined coils and the surface stripe patterned magnetic film are arranged perpendicularly.

[0078] The surface smooth magnetic film 6 and the plurality of strip grid pattern magnetic films 7 are rectangular; the long side of the strip grid pattern magnetic film 7 is perpendicular to the long side of the surface smooth magnetic film 6; the aspect ratio of the single strip grid pattern magnetic film 7 is not less than ten; the length of the strip grid pattern magnetic film 7 is the same as the width of the surface smooth magnetic film 6; the surface smooth magnetic film 6 is located on one side of the combined coil; the two ends of the excitation coil 3 and the inductive coil 4 are provided with electrodes, one of the electrodes of the excitation coil 3 is the input end of the electric excitation signal, and the other electrode is the output end of the electric excitation signal; and the potential difference between the two electrodes of the inductive coil 4 is the output signal.

[0079] The electrodes on the outer side of the excitation coil 3 and the inductive coil 4 are located on the outer side of the top magnetic film; the electrodes on the inner side of the excitation coil 3 and the inductive coil 4 are located on the bottom of the top magnetic film; the electrodes on the inner side of the two excitation coils 3 are electrically connected through a connecting line; and the electrodes on the inner side of the two inductive coils 4 are electrically connected through a connecting line.

[0080] Embodiment 5

[0081] Figure 9 The figure is the sensitivity data of the sensors respectively prepared by the surface smooth magnetic film and the surface strip grid pattern magnetic film. The length, width and thickness of the surface smooth magnetic film are 6 mm, 2 mm and 20 μ m respectively, and the total length, width and thickness of the surface strip grid pattern magnetic film are also 6 mm, 2 mm and 20 μ m respectively, the width of the strip grid pattern magnetic film is 40 μ m, the thickness is 10 μ m, and the distance between the adjacent strip grid pattern magnetic films is 0.46 mm. According to the experimental data, compared with the sensor prepared by the surface smooth magnetic film with the same thickness, the maximum value of the sensitivity of the sensor prepared by the surface strip grid pattern magnetic film is increased by 736%, which is caused by the weakening of the demagnetization effect along the length direction of the surface strip grid pattern magnetic film. Therefore, it can be proved that the strip grid pattern processed on the surface of the surface smooth magnetic film can significantly improve the sensitivity of the sensor.

[0082] Although the present application has been disclosed with the preferred embodiments as above, they are not intended to limit the present application, and any person skilled in the art can make various changes or modifications without departing from the spirit and scope of the present application, therefore, the protection scope of the present application should be defined by the protection scope of the claims of the present application.

Claims

1. A low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor, characterized by, The magnetic sensor comprises, from bottom to top, an insulating substrate, a bottom magnetic film, a combined coil and a top magnetic film; an insulating isolation layer is arranged between the combined coil and the bottom magnetic film and between the combined coil and the top magnetic film; the bottom magnetic film and the top magnetic film are rectangular planar magnetic films or surface strip grid pattern magnetic films; at least one of the bottom magnetic film and the top magnetic film is a surface strip grid pattern magnetic film; the combined coil is a double helix coil structure comprising alternating excitation coils and induction coils, and the excitation coils and the induction coils are planar rectangular helix structures; the combined coil and the surface strip grid pattern magnetic film are arranged in perpendicular intersection; The surface strip grid pattern magnetic film comprises a surface smooth magnetic film and a plurality of strip grid pattern magnetic films; the plurality of strip grid pattern magnetic films are arranged on the surface smooth magnetic film at equal intervals; the surface smooth magnetic film and the single strip grid pattern magnetic film are rectangular; the long side of the strip grid pattern magnetic film is perpendicular to the long side of the surface smooth magnetic film; the length-width ratio of the single strip grid pattern magnetic film is not less than ten; the length of the strip grid pattern magnetic film is the same as the width of the surface smooth magnetic film; the surface smooth magnetic film is located on one side of the combined coil; the two ends of the excitation coil and the induction coil are provided with electrodes, one of the electrodes of the excitation coil is an input end of an electric excitation signal, and the other electrode is an output end of the electric excitation signal; the potential difference between the two electrodes of the induction coil is an output signal.

2. The low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor according to claim 1, characterized in that, The substrate is a silicon substrate, a quartz glass substrate or an alumina substrate.

3. The low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor according to claim 1, characterized in that, The materials of the excitation coil and the induction coil are copper.

4. A low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor according to claim 2 or 3, characterized in that, The combined coil is provided with one or more excitation coils, and the excitation coils of the multiple combined coils are electrically connected; the induction coils of the multiple combined coils are electrically connected.

5. A low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor according to claim 4, characterized in that, The insulating isolation layer is made of silicon nitride or polyimide.

6. The low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor according to claim 4, characterized in that, The low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor is prepared by a micro processing process.

7. The low-noise high-sensitivity micro planar laminated magnetic induction type magnetic sensor according to claim 6, characterized in that, The electrodes of the excitation coil and the induction coil are located on the side of the top magnetic film or the bottom of the top magnetic film; when the electrodes are located at the bottom of the top magnetic film, corresponding holes are arranged on the top magnetic film to expose the positions of the electrodes.

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