A single-axis weak magnetic sensor sensitive chip based on magnetoresistance effect

Abstract

A kind of uniaxial weak magnetic sensor sensitive chip based on magnetoresistance effect, it relates to a weak magnetic sensor sensitive chip.The present application is to solve the problem of poor measurement accuracy of existing weak magnetic sensor.The present application includes electrode lead layer (10), four-terminal wheatstone bridge type magnetoresistance (20), set / reset current band (31) and bias magnetic field band (41), electrode lead layer (10), four-terminal wheatstone bridge type magnetoresistance (20), set / reset current band (31) and bias magnetic field band (41) are sequentially encapsulated from top to bottom, and between electrode lead layer (10) and four-terminal wheatstone bridge type magnetoresistance (20), between four-terminal wheatstone bridge type magnetoresistance (20) and set / reset current band (31), between set / reset current band (31) and bias magnetic field band (41) are provided with insulating layer;Four-terminal wheatstone resistance bridge layer (21) in four-terminal wheatstone bridge type magnetoresistance (20) is encapsulated on magnetoresistance layer (22).The present application is used for weak magnetic measurement.

Description

TECHNICAL FIELD

[0001] The application relates to a sensitive chip, in particular to a uniaxial weak magnetic sensor sensitive chip based on a magnetic resistance effect. BACKGROUND

[0002] From the perspective of magnetic field sensing range, magnetic field sensors can be divided into three categories: low-intensity magnetic field sensors, medium-intensity magnetic field sensors and high-intensity magnetic field sensors. The low-intensity magnetic field sensor, also known as a weak magnetic measurement sensor, is usually used to detect a magnetic field below 0.1 nT.

[0003] Weak magnetic measurement is widely used in both military and civilian fields. For example, in the civilian field, high-precision magnetic measurement instruments are the main equipment for resource exploration; and in the field of biological medical engineering, such as nuclear magnetic resonance, lung magnetic, stomach magnetic and brain magnetic diagnosis, weak magnetic measurement instruments are indispensable. Therefore, the weak magnetic sensor technology to a great extent represents the development level of the national magnetic measurement technology.

[0004] At present, the commonly used weak magnetic sensor in China is a mechanical weak magnetic sensor such as a fluxgate and a gyro meter. Due to the coil design and processing problems, the sensitive chip based on the magnetic resistance effect is still in the laboratory stage, and the measurement precision is low, and there is no mature product.

[0005] In summary, the existing weak magnetic sensor has the problem of poor measurement precision. SUMMARY

[0006] The application aims to solve the problem of poor measurement precision of the existing weak magnetic sensor, and further provides a uniaxial weak magnetic sensor sensitive chip based on a magnetic resistance effect.

[0007] The technical scheme of the application is: a uniaxial weak magnetic sensor sensitive chip based on a magnetic resistance effect comprises an electrode lead layer, a four-terminal Wheatstone bridge type magnetic resistance, a set / reset current band and a bias magnetic field band, the electrode lead layer, the four-terminal Wheatstone bridge type magnetic resistance, the set / reset current band and the bias magnetic field band are sequentially encapsulated from top to bottom, and an insulating layer is arranged between the electrode lead layer and the four-terminal Wheatstone bridge type magnetic resistance, between the four-terminal Wheatstone bridge type magnetic resistance and the set / reset current band, and between the set / reset current band and the bias magnetic field band; wherein the four-terminal Wheatstone bridge type magnetic resistance comprises a four-terminal Wheatstone resistance bridge layer and a magnetic resistance layer, and the four-terminal Wheatstone resistance bridge layer is encapsulated on the magnetic resistance layer.

[0008] Further, the electrode lead layer is provided with a first power supply electrode hole, an output positive electrode hole, a ground electrode hole, a set / reset negative electrode hole, an output negative electrode hole, a second power supply electrode hole, a bias negative electrode hole, a set / reset positive electrode hole and a bias positive electrode hole; the first power supply electrode hole, the output positive electrode hole, the ground electrode hole, the set / reset negative electrode hole, the output negative electrode hole and the second power supply electrode hole are sequentially arranged from top to bottom on the right side of the electrode lead layer, the bias negative electrode hole is arranged on the left side of the output negative electrode hole and the second power supply electrode hole, and the bias positive electrode hole and the set / reset positive electrode hole are sequentially arranged from top to bottom on the left side of the electrode lead layer.

[0009] Further, the magnetoresistance layer comprises 24 double-tipped magnetoresistance strips arranged in parallel, and the material of the double-tipped magnetoresistance strips is iron-nickel alloy.

[0010] Further, the four-terminal Wheatstone bridge layer comprises a bridge layer body, an upper power supply electrode, an output positive electrode, a ground electrode, an output negative electrode and a lower power supply electrode, and the upper power supply electrode, the output positive electrode, the ground electrode, the output negative electrode and the lower power supply electrode are respectively arranged on the bridge layer body, wherein the installation positions of the upper power supply electrode, the output positive electrode, the ground electrode, the output negative electrode and the lower power supply electrode correspond to the first power supply electrode hole, the output positive electrode hole, the ground electrode hole, the output negative electrode hole and the second power supply electrode hole respectively.

[0011] Further, the four-terminal Wheatstone bridge layer further comprises a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm, and the first bridge arm, the second bridge arm, the third bridge arm and the fourth bridge arm are sequentially arranged from top to bottom on the bridge layer body, wherein the upper power supply electrode is connected with the first bridge arm, the output positive electrode is connected with the second bridge arm and the first bridge arm, the ground electrode is connected with the third bridge arm and the second bridge arm, and the output negative electrode is connected with the fourth bridge arm and the third bridge arm.

[0012] Further, the first bridge arm, the second bridge arm, the third bridge arm and the fourth bridge arm each comprise a serpentine short connection strip, and the material of the serpentine short connection strip is aluminum or gold.

[0013] Further, the serpentine short connection strip of the first bridge arm is 6 rows of independent short connection blocks arranged in parallel and inclined downward to the left by 45°, and the vertical width of the independent short connection block is greater than the width of the double-tipped magnetoresistance strip; the serpentine short connection strip of the second bridge arm is 6 rows of independent short connection blocks arranged in parallel and inclined downward to the right by 45°, and the independent short connection block is perpendicular to the independent short connection block of the first bridge arm, and the vertical width of the independent short connection block is greater than the width of the double-tipped magnetoresistance strip; the serpentine short connection strip of the third bridge arm is 6 rows of independent short connection blocks arranged in parallel and inclined downward to the left by 45°, and the independent short connection block is perpendicular to the independent short connection block of the second bridge arm, and the vertical width of the independent short connection block is greater than the width of the double-tipped magnetoresistance strip; and the serpentine short connection strip of the fourth bridge arm is 6 rows of independent short connection blocks arranged in parallel and inclined downward to the right by 45°, and the vertical width of the independent short connection block is greater than the width of the double-tipped magnetoresistance strip.

[0014] Further, the set / reset current band adopts a counterclockwise spiral ring structure from inside to outside, and the two ends are connected with the set / reset negative electrode hole and the set / reset positive electrode hole.

[0015] Further, the material of the set / reset current band is metal aluminum.

[0016] Further, the material of the bias magnetic field band is metal aluminum.

[0017] Compared with the prior art, the present application has the following effects:

[0018] The double-tipped magnetic resistance strip can effectively form a magnetic resistance effect on the detected weak magnetic field, the symmetrical arrangement of multiple magnetic resistance strips greatly reduces the influence of self-heating of the circuit and external temperature, and in the set / reset current band, a strong magnetic field is formed by passing a strong current to forcibly reset the magnetic sensitive element and eliminate the imbalance caused by the previous measurement process. In the bias magnetic field band, the magnetic field of the external environment can be offset by applying a direct current, so that the magnetic sensitive element only measures in a closed environment of the measured magnetic field, greatly improving the extraction accuracy of the weak magnetic signal, avoiding the influence of external noise, and significantly improving the measurement accuracy of the weak magnetic signal. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the front view of the present application. Figure 2 is a structural schematic diagram of the electrode hole lead layer. Figure 3 is a structural schematic diagram of the four-terminal Wheatstone resistance bridge layer. Figure 4 is a structural schematic diagram of the magnetic resistance layer. Figure 5 is a structural schematic diagram of the set / reset current band layer. Figure 6 is a structural schematic diagram of the bias magnetic field band layer. DETAILED DESCRIPTION

[0020] Specific implementation one: combined Figures 1 to 6 In this embodiment, a single-axis weak magnetic sensor sensitive chip based on the magnetic resistance effect includes an electrode lead layer 10, a four-terminal Wheatstone bridge magnetic resistance 20, a set / reset current band 31, and a bias magnetic field band 41. The electrode lead layer 10, the four-terminal Wheatstone bridge magnetic resistance 20, the set / reset current band 31, and the bias magnetic field band 41 are sequentially encapsulated from top to bottom, and an insulating layer is arranged between the electrode lead layer 10 and the four-terminal Wheatstone bridge magnetic resistance 20, between the four-terminal Wheatstone bridge magnetic resistance 20 and the set / reset current band 31, and between the set / reset current band 31 and the bias magnetic field band 41. The four-terminal Wheatstone bridge magnetic resistance 20 includes a four-terminal Wheatstone resistance bridge layer 21 and a magnetic resistance layer 22, and the four-terminal Wheatstone resistance bridge layer 21 is encapsulated on the magnetic resistance layer 22.

[0021] The four metal layers of the embodiment are all rectangular in shape with 2.725 mm in width and 2.560 mm in length.

[0022] Specific implementation two: combination Figure 2 In the embodiment, the electrode lead layer 10 is provided with a first power supply electrode hole 101, an output positive electrode hole 102, a ground electrode hole 103, a set / reset negative electrode hole 104, an output negative electrode hole 105, a second power supply electrode hole 106, a bias negative electrode hole 107, a set / reset positive electrode hole 108, and a bias positive electrode hole 109. The first power supply electrode hole 101, the output positive electrode hole 102, the ground electrode hole 103, the set / reset negative electrode hole 104, the output negative electrode hole 105, and the second power supply electrode hole 106 are sequentially arranged from top to bottom on the right side of the electrode lead layer 10. The bias negative electrode hole 107 is arranged on the left side of the output negative electrode hole 105 and the second power supply electrode hole 106. The bias positive electrode hole 109 and the set / reset positive electrode hole 108 are sequentially arranged from top to bottom on the left side of the electrode lead layer 10. In this way, the pins can be easily distinguished and led out during chip packaging. The other components and connection relationships are the same as those in the first embodiment.

[0023] The electrode lead layer 10 of the embodiment is placed on the top of the sensitive chip, and the commonly used material is aluminum or copper.

[0024] Specific implementation three: combination Figure 4 In the embodiment, the magnetoresistance layer 22 includes 24 double-tipped magnetoresistance strips 2201 arranged in parallel, and the material of the double-tipped magnetoresistance strips 2201 is iron-nickel alloy. In this way, the structure is compact, the volume is small, the processing is convenient, and the magnetic field has obvious impedance effect on the measurement. The other components and connection relationships are the same as those in the first or second embodiment.

[0025] Specific implementation four: combination Figure 3In this embodiment, the four-terminal Wheatstone bridge layer 21 includes a bridge layer body, an upper power supply electrode 2101, an output positive electrode 2102, a ground electrode 2103, an output negative electrode 2104, and a lower power supply electrode 2105. The upper power supply electrode 2101, the output positive electrode 2102, the ground electrode 2103, the output negative electrode 2104, and the lower power supply electrode 2105 are respectively installed on the bridge layer body, and the installation positions of the upper power supply electrode 2101, the output positive electrode 2102, the ground electrode 2103, the output negative electrode 2104, and the lower power supply electrode 2105 correspond to the first power supply electrode hole 101, the output positive electrode hole 102, the ground electrode hole 103, the output negative electrode hole 105, and the second power supply electrode hole 106 respectively. In this way, one-to-one correspondence with the electrode holes in the first embodiment is facilitated. The other components and connection relationships are the same as those in the first, second, or third embodiments.

[0026] Embodiment five: combination Figure 3 In this embodiment, the four-terminal Wheatstone bridge layer 21 further includes a first bridge arm 2109, a second bridge arm 2108, a third bridge arm 2107, and a fourth bridge arm 2106. The first bridge arm 2109, the second bridge arm 2108, the third bridge arm 2107, and the fourth bridge arm 2106 are installed on the bridge layer body in order from top to bottom. The upper power supply electrode 2101 is connected to the first bridge arm 2109, the output positive electrode 2102 is connected to the second bridge arm 2108 and the first bridge arm 2109, the ground electrode 2103 is connected to the third bridge arm 2107 and the second bridge arm 2108, and the output negative electrode 2104 is connected to the fourth bridge arm 2106 and the third bridge arm 2107. A Wheatstone bridge is formed to convert the changing magnetic signal into an electrical signal for easy extraction. The other components and connection relationships are the same as those in the first, second, third, or fourth embodiments.

[0027] Embodiment six: combination Figure 3 In this embodiment, the first bridge arm 2109, the second bridge arm 2108, the third bridge arm 2107, and the fourth bridge arm 2106 each include a serpentine shorting bar made of aluminum or gold. In this way, the four-terminal Wheatstone bridge layer 21 formed by the bridge arms is arranged in the magnetoresistive layer 22, facilitating signal extraction. The other components and connection relationships are the same as those in the first, second, third, fourth, or fifth embodiments.

[0028] Embodiment seven: combination Figure 3 In this embodiment, the serpentine shorting bar of the first bridge arm 2109 is a 6-row parallel and left-down 45° inclined independent shorting block, and the vertical width of the independent shorting block is greater than the width of the double-tipped magnetoresistive strip 2201.

[0029] The snake-shaped short-circuiting strip of the second bridge arm 2108 is 6 rows of parallel independent short-circuiting blocks which are inclined downward by 45° to the right, and is perpendicular to the independent short-circuiting blocks of the first bridge arm 2109, and the vertical width of the independent short-circuiting blocks is greater than the width of the double-tipped magnetic resistance strip 2201;

[0030] The snake-shaped short-circuiting strip of the third bridge arm 2107 is 6 rows of parallel independent short-circuiting blocks which are inclined downward by 45° to the left, and is perpendicular to the independent short-circuiting blocks of the second bridge arm 2108, and the vertical width of the independent short-circuiting blocks is greater than the width of the double-tipped magnetic resistance strip 2201;

[0031] The snake-shaped short-circuiting strip of the fourth bridge arm 2106 is 6 rows of parallel independent short-circuiting blocks which are inclined downward by 45° to the right, and the vertical width of the independent short-circuiting blocks is greater than the width of the double-tipped magnetic resistance strip 2201.

[0032] In this way, the four-terminal Wheatstone bridge structure is compact, easy to process, and the connection points of each bridge arm are easy to correspond to the electrode holes. The other components and connection relationships are the same as those in any one of the first to seventh embodiments.

[0033] Embodiment eight: in combination with Figure 5 In this embodiment, the set / reset current band 31 adopts a clockwise spiral ring structure from inside to outside, and the two ends are connected with the set / reset negative electrode hole 104 and the set / reset positive electrode hole 108. In this way, it is convenient to connect with the handle, and the connection is convenient and easy to disassemble and maintain. The other components and connection relationships are the same as those in any one of the first to seventh embodiments.

[0034] Embodiment nine: in combination with Figure 5 In this embodiment, the material of the set / reset current band 31 is metal aluminum. In this way, the current flowing through the set / reset current band 31 forms a strong magnetic field, which resets the magnetic sensitive element and does not affect the measurement of the magnetic sensitive element. The other components and connection relationships are the same as those in any one of the first to eighth embodiments.

[0035] Embodiment ten: in combination with Figure 6 In this embodiment, the material of the bias magnetic field band 41 is metal aluminum. In this way, it is used to offset the influence of the external environment on the magnetic sensitive element, or provide a feedback signal, and does not affect the measurement of the magnetic sensitive element. The other components and connection relationships are the same as those in any one of the first to eighth embodiments.

[0036] In combination with Figures 1 to 6 to explain the working principle of the present application:

[0037] In the invention, the upper electrode hole lead layer 10 leads the external connection port to the proper position through the metal lead to form the pressure welding area; the four-terminal Wheatstone bridge layer 21 is connected with the magnetic resistance layer 22, no insulation layer is arranged between them, the magnetic resistance strips are symmetrically distributed, the influence of the circuit and the temperature on the magnetic resistance characteristics is eliminated, and the influence of the defects possibly existing in the single magnetic resistance design on the output characteristics of the bridge-type magnetic resistance circuit is also eliminated; the setting / resetting current band layer 31 makes the weak magnetic sensor not need external coil, through the setting / resetting current band integrated in the chip interior, the magnetic sensitive element in the sensor interior can be recalibrated or reversed, and the imbalance caused by the electronic circuit and the temperature can be eliminated; the bias magnetic field band layer 41 can operate in multiple modes, one is that the rated current passes through the current band, which is equivalent to providing a fixed magnetic field in the direction intersecting with the sensitive axis, so that the direct current can pass through the current band to offset the unwanted external magnetic field. Two is that the feedback signal current is provided on the current band sheet, so that the weak magnetic sensor works in the closed loop mode.

Claims

1. A single-axis weak magnetic field sensor sensing chip based on the magnetoresistive effect, characterized in that: It includes an electrode lead layer (10), a four-terminal Wheatstone bridge magnetoresistive (20), a set / reset current band (31), and a bias magnetic field band (41). The electrode lead layer (10), the four-terminal Wheatstone bridge magnetoresistive (20), the set / reset current band (31), and the bias magnetic field band (41) are sequentially packaged from top to bottom. An insulating layer is provided between the electrode lead layer (10) and the four-terminal Wheatstone bridge magnetoresistive (20), between the four-terminal Wheatstone bridge magnetoresistive (20) and the set / reset current band (31), and between the set / reset current band (31) and the bias magnetic field band (41). Among them, the four-terminal Wheatstone bridge magnetoresistive (20) includes a four-terminal Wheatstone resistor bridge layer (21) and a magnetoresistive layer (22), with the four-terminal Wheatstone resistor bridge layer (21) encapsulated on the magnetoresistive layer (22); The magnetoresistive layer (22) includes 24 parallel double-pointed magnetoresistive strips (2201), the material of which is an iron-nickel alloy; The four-terminal Wheatstone resistor bridge layer (21) includes a resistor bridge layer body, an upper power supply electrode (2101), an output positive electrode (2102), a ground electrode (2103), an output negative electrode (2104), and a lower power supply electrode (2105). The upper power supply electrode (2101), the output positive electrode (2102), the ground electrode (2103), the output negative electrode (2104), and the lower power supply electrode (2105) are respectively mounted on the resistor bridge layer body. The mounting positions of the upper power supply electrode (2101), the output positive electrode (2102), the ground electrode (2103), the output negative electrode (2104), and the lower power supply electrode (2105) correspond to the first power supply electrode hole (101), the output positive electrode hole (102), the ground electrode hole (103), the output negative electrode hole (105), and the second power supply electrode hole (106), respectively. The set / reset current band (31) adopts a counterclockwise spiral ring structure from the inside to the outside, and the notches at both ends are connected to the set / reset negative electrode hole (104) and the set / reset positive electrode hole (108).

2. The single-axis weak magnetic field sensor sensing chip based on magnetoresistive effect according to claim 1, characterized in that: The electrode lead layer (10) has a first power supply electrode hole (101), an output positive electrode hole (102), a ground electrode hole (103), a set / reset negative electrode hole (104), an output negative electrode hole (105), a second power supply electrode hole (106), a bias negative electrode hole (107), a set / reset positive electrode hole (108), and a bias positive electrode hole (109). The first power supply electrode hole (101), the output positive electrode hole (102), the ground electrode hole (103), the set / reset negative electrode hole (104), the output negative electrode hole (105), and the second power supply electrode hole (106) are sequentially opened on the right side of the electrode lead layer (10) from top to bottom. The bias negative electrode hole (107) is opened on the left side of the output negative electrode hole (105) and the second power supply electrode hole (106). The bias positive electrode hole (109) and the set / reset positive electrode hole (108) are sequentially opened on the left side of the electrode lead layer (10) from top to bottom.

3. The single-axis weak magnetic sensor sensing chip based on magnetoresistive effect according to claim 2, characterized in that: The four-terminal Wheatstone resistor bridge layer (21) also includes a first bridge arm (2109), a second bridge arm (2108), a third bridge arm (2107), and a fourth bridge arm (2106), which are installed sequentially from top to bottom on the resistor bridge layer body. The upper power supply electrode (2101) is connected to the first bridge arm (2109). The positive output (2102) is connected to the second bridge arm (2108) and the first bridge arm (2109). The grounding electrode (2103) is connected to the third bridge arm (2107) and the second bridge arm (2108). The output negative electrode (2104) is connected to the fourth bridge arm (2106) and the third bridge arm (2107).

4. The single-axis weak magnetic sensor sensing chip based on magnetoresistive effect according to claim 3, characterized in that: Each of the first bridge arm (2109), the second bridge arm (2108), the third bridge arm (2107), and the fourth bridge arm (2106) includes a serpentine shorting strip, the serpentine shorting strip being made of aluminum or gold.

5. The single-axis weak magnetic sensor sensing chip based on magnetoresistive effect according to claim 4, characterized in that: The serpentine shorting bar of the first bridge arm (2109) consists of 6 rows of parallel independent shorting blocks that tilt downward to the left at 45°. The vertical width of the independent shorting blocks is greater than the width of the double-pointed magnetic reluctance bar (2201). The serpentine shorting bar of the second bridge arm (2108) consists of 6 rows of parallel independent shorting blocks that tilt downward to the right at 45° and are perpendicular to the independent shorting blocks of the first bridge arm (2109). The vertical width of the independent shorting blocks is greater than the width of the double-pointed magnetic reluctance bar (2201). The serpentine shorting bar of the third bridge arm (2107) consists of 6 rows of parallel independent shorting blocks that tilt 45° to the lower left and are perpendicular to the independent shorting blocks of the second bridge arm (2108). The vertical width of the independent shorting blocks is greater than the width of the double-pointed magnetic reluctance bar (2201). The serpentine shorting bar of the fourth bridge arm (2106) consists of 6 rows of parallel independent shorting blocks that tilt downward to the right at 45°. The vertical width of the independent shorting blocks is greater than the width of the double-pointed magnetic reluctance bar (2201).

6. The single-axis weak magnetic sensor sensing chip based on magnetoresistive effect according to claim 1, characterized in that: The material of the set / reset current band (31) is aluminum.

7. The single-axis weak magnetic sensor sensing chip based on magnetoresistive effect according to claim 1, characterized in that: The bias magnetic field band (41) is made of aluminum.

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