WO2015010649A1 - 一种单磁阻tmr磁场传感器芯片及验钞机磁头 - Google Patents

一种单磁阻tmr磁场传感器芯片及验钞机磁头 Download PDF

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Publication number
WO2015010649A1
WO2015010649A1 PCT/CN2014/082986 CN2014082986W WO2015010649A1 WO 2015010649 A1 WO2015010649 A1 WO 2015010649A1 CN 2014082986 W CN2014082986 W CN 2014082986W WO 2015010649 A1 WO2015010649 A1 WO 2015010649A1
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Prior art keywords
magnetic field
mtj
sensor chip
field sensor
chip
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PCT/CN2014/082986
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English (en)
French (fr)
Inventor
迪克·詹姆斯·G
郭海平
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江苏多维科技有限公司
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Application filed by 江苏多维科技有限公司 filed Critical 江苏多维科技有限公司
Priority to JP2016528338A priority Critical patent/JP6425313B2/ja
Priority to EP14829581.9A priority patent/EP3026451B1/en
Priority to US14/907,691 priority patent/US9804235B2/en
Publication of WO2015010649A1 publication Critical patent/WO2015010649A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G01R33/098—Magnetoresistive devices comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/04—Testing magnetic properties of the materials thereof, e.g. by detection of magnetic imprint

Definitions

  • the present invention relates to the field of magnetic field sensors, and more particularly to a single magnetoresistive TMR magnetic field sensor chip and a magnetic detector head made based on the chip.
  • the vending machine head is required in equipment such as vending machines and money counters.
  • the magnetic head technology of the mainstream money detector uses a magnetic head with indium antimonide as a sensitive material.
  • the magnetic force line is perpendicular to the detection surface.
  • the invention provides a single magnetoresistive TMR magnetic field sensor chip, comprising:
  • a single magnetoresistive TMR magnetic field sensor chip is mounted above a magnetic excitation element, the sensing direction of the chip is parallel to the surface of the chip, and the direction of the excitation magnetic field generated by the magnetic excitation element at the chip is perpendicular to the surface of the chip, and the single magnetoresistive TMR magnetic field sensor
  • the chip includes:
  • a substrate a magnetic biasing structure deposited on the substrate, a magnetoresistive element, and input and output terminals;
  • the magnetoresistive element is composed of at least one MTJ unit
  • the MTJ unit is composed of at least one MTJ string
  • the MTJ string is composed of at least one MTJ
  • the sensing direction of the magnetoresistive element and the sensing direction of the MTJ are the same as the sensing direction of the chip;
  • the direction of the bias magnetic field generated by the magnetic biasing structure at the chip is perpendicular to the sensing direction of the chip.
  • the magnetoresistive element is composed of at least two MTJ units connected in parallel or in series, and the MTJ unit is arranged along a sensing direction perpendicular or parallel to the single magnetoresistive TMR magnetic field sensor chip, and the center distance between two adjacent MTJ units is 200 ⁇ 800.
  • the MTJ unit is composed of at least two MTJs connected in series or in series, and the MTJ strings are arranged along the sensing direction perpendicular or parallel to the single magnetoresistive TMR magnetic field sensor chip, and the center distance between two adjacent MTJ strings is 20-100.
  • the MTJ string is composed of at least two MTJs connected in parallel or in series, and the MTJs are arranged in a direction perpendicular or parallel to the sensing direction of the single magnetoresistive TMR magnetic field sensor chip, and the center distance between two adjacent MTJs is 1-20 micrometers.
  • the MTJ has an elliptical shape in plan view, and the ratio of the length of the major axis to the minor axis is greater than 3, and the short axis of the MTJ is parallel to the sensing direction of the chip.
  • the magnetization direction of the free layer in the MTJ is parallel to the long axis direction of the MTJ under the action of the magnetic biasing structure.
  • the magnetic biasing structure is in the form of a block or a layer, and the material thereof is an alloy composed of Cr, Co, Pt, Pd, Ni or Fe.
  • the magnetic biasing structure is composed of permanent magnets between two adjacent MTJ strings; along the magnetization direction of the permanent magnets, permanent magnets are placed on both sides of the MTJ; magnetic fields generated by the magnetic excitation elements at the permanent magnets It is less than half of the coercive force of the permanent magnet and is less than 0.1T.
  • the magnetic biasing structure is composed of a magnetic film deposited on the MTJ; the magnetic excitation element generates a magnetic field at the magnetic film that is less than half the coercive force of the magnetic film and is less than 0.1T.
  • the magnetic biasing structure is formed by an exchange layer deposited on the MTJ, the exchange layer comprising an antiferromagnetic layer and a ferromagnetic layer weakly coupled to the antiferromagnetic layer.
  • the input and output terminals each comprise at least two wire bond pads, each wire bond pad being located at both ends of the single magnetoresistive TMR magnetic field sensor chip.
  • the plurality of single magnetoresistive TMR magnetic field sensor chips are electrically connected by wire bonding pads to form a sensor chip combination, and the sensing area of the sensor chip combination is larger than the sensing area of the single single magnetoresistive TMR magnetic field sensor chip.
  • the wire bond pads have a length of 15-2000 microns and a width of 15-1000 microns.
  • the substrate is provided with electrical connection conductors for electrical connection, and the width of the electrical connection conductor is not less than 10 microns.
  • the single magnetoresistive TMR magnetic field sensor chip has a length of 500-3000 microns and a width of 20-1500 microns.
  • the invention also provides a money detector magnetic head, the magnetic head comprising:
  • the magnetic excitation component is mounted under the single magnetoresistive TMR magnetic field sensor chip for providing an excitation magnetic field to generate an applied magnetic field in the direction in which the chip is sensed in the space to be measured;
  • a single magnetoresistive TMR magnetic field sensor chip senses an applied magnetic field and converts it into an electrical signal
  • the signal processing circuit converts the electrical signal and passes it through the board to the output pin.
  • the present invention discloses the following technical effects:
  • the invention provides a single magnetoresistive TMR magnetic field sensor chip with a sensing direction parallel to the surface of the chip.
  • the direction of the excitation magnetic field generated by the magnetic excitation element at the chip is perpendicular to the surface of the chip, and the magnetoresistive element of the chip is composed of MTJ;
  • the sensing direction of the component and the sensing direction of the MTJ are the same as the sensing direction of the chip; the direction of the bias magnetic field generated by the magnetic biasing structure at the chip is perpendicular to the sensing direction of the chip.
  • the chip of the invention has high sensitivity, high signal to noise ratio, small volume, high temperature stability and high reliability.
  • FIG. 1 is a schematic diagram of a single magnetoresistive TMR magnetic field sensor chip
  • FIG. 2 is a schematic view showing a connection manner between two or more single magnetoresistive TMR magnetic field sensor chips
  • Figure 3 (a) is a schematic structural view of the MTJ
  • Figure 3 (b) is a relationship between the resistance value and the applied magnetic field
  • Figure 4 (a) is an application schematic diagram of a single magnetoresistive TMR magnetic field sensor chip
  • 4(b) is a graph showing the relationship between the output voltage of the sensor chip corresponding to FIG. 4(a) and the applied magnetic field;
  • Figure 5 (a) is another application schematic diagram of a single magnetoresistive TMR magnetic field sensor chip
  • Figure 5 (b) is a graph showing the relationship between the output voltage of the sensor chip corresponding to Figure 5 (a) and the applied magnetic field;
  • FIG. 6 is a schematic diagram of an MTJ unit composed of a first magnetic bias method
  • FIG. 8 is a schematic structural view of an MTJ in a first magnetic bias method
  • FIG. 9 is a schematic diagram of an MTJ unit composed of a second magnetic bias method
  • FIG. 10 is a schematic structural diagram of an MTJ in a second magnetic bias method
  • FIG. 11 is a schematic structural diagram of an MTJ in a third magnetic biasing method.
  • Figure 12 is a schematic illustration of the manner of connection between multiple MTJs.
  • Embodiment 1 of the present invention provides a single magnetoresistance TMR (Tunnel Magnetoresistance) Magnetic field sensor chip.
  • 1 is a schematic diagram of a single magnetoresistive TMR magnetic field sensor chip 101.
  • the chip may have a length of 500-3000 microns and a width of 20-1500 microns, but is not limited to the above dimensions. All of the components in the chip are located on the substrate 102.
  • the substrate 102 can be formed of a material that can be fabricated as an integrated circuit such as silicon, ceramic, or resin. A silicon substrate is used in the present invention.
  • Magnetoresistive element 108 consists of a magnetic tunnel junction MTJ (Magnetic Tunnel The Junction unit 109 is constructed or constructed by connecting at least two MTJ units 109 in series or in parallel.
  • the magnetoresistive element 108 shown in FIG. 1 is composed of five MTJ units 109 connected in parallel.
  • One MTJ unit 109 is composed of one MTJ string, or two or more MTJs are connected in series or in series.
  • Each MTJ string consists of one MTJ or consists of two or more MTJs connected in parallel or in series.
  • a single magnetoresistive TMR magnetic field sensor chip like a conventional resistor, has two terminals, an input terminal and an output terminal, and each terminal has at least two wire bond pads.
  • the wire bond pad can also be used for electrical connection between a plurality of single magnetoresistive TMR magnetic field sensor chips, which form a sensor chip combination, the sensing area of the sensor chip combination is larger than the sensing area of the single single magnetoresistive TMR magnetic field sensor chip. area.
  • 104 and 105 in Figure 1 are two wire bond pads for one terminal of a single magnetoresistive TMR magnetic field sensor chip, and 106 and 107 are two wire bond pads for the other terminal of a single magnetoresistive TMR magnetic field sensor chip.
  • the wire bond pads 104-107 have a length of 15-2000 microns and a width of 15-1000 microns.
  • an electrical connection conductor 103 which is made of a material of high electrical conductivity and has a width of not less than 10 ⁇ m.
  • the chip is mounted above the magnetic excitation element, and the direction of the excitation magnetic field generated by the magnetic excitation element at the chip is perpendicular to the surface of the chip.
  • the chip also includes a magnetic biasing structure (not shown) deposited on the substrate.
  • the magnetic biasing structure may be in the form of a block or a layer, and the material used may be an alloy composed of Cr, Co, Pt, Pd, Ni or Fe.
  • the direction of the bias magnetic field generated by the magnetic biasing structure at the chip is perpendicular to the sensing direction of the chip to operate the magnetoresistive element in the linear region and reduce the hysteresis of the MTJ.
  • the sensing direction of the chip is parallel to the surface of the chip, and the sensing direction of the magnetoresistive element and the sensing direction of the MTJ are the same as the sensing direction of the chip.
  • an MTJ is used as an inductive element, which has the advantages of high sensitivity, small size, low cost, and low power consumption.
  • the specific structure of the MTJ is shown in FIG. 3(a).
  • the tunnel layer 303 is between the ferromagnetic free layer 302 and the magnetic pinned layer 304.
  • the magnetization direction 305 of the magnetic pinned layer 304 is perpendicular to the bias provided by the magnetic bias structure. Set the direction of the magnetic field. Under the action of the bias magnetic field, if there is no applied magnetic field, the magnetization direction of the ferromagnetic free layer 302 is the same as the direction of the bias magnetic field.
  • the magnetization direction of the ferromagnetic free layer 302 When there is an applied magnetic field, the magnetization direction of the ferromagnetic free layer 302 will change following the applied magnetic field.
  • the resistance between the A terminal and the B terminal of the two terminals of the MTJ is macroscopically exhibited, and the resistance value changes with the magnetization direction of the ferromagnetic free layer 302: when the magnetization direction and magnetic properties of the ferromagnetic free layer 302
  • the magnetization direction 305 of the pinned layer 304 is parallel, as indicated by the arrow 307, and the ferromagnetic free layer 302 is magnetized to saturation, and the resistance between the A terminal and the B terminal is the smallest, denoted as Rmin, and the applied magnetic field at this time is recorded as Hsat-; when the magnetization direction of the ferromagnetic free layer 302 is anti-parallel to the magnetization direction 305 of the magnetic pinned layer 304, as indicated by arrow 306, and the ferromagnetic free layer
  • the maximum resistance is recorded as Rmax, and the applied magnetic field at this time is recorded as Hsat+, as shown in Fig. 3(b).
  • the resistance of the MTJ varies linearly between Rmin and Rmax with the applied magnetic field. Therefore, the measurement of the external magnetic field can be realized by the change of the resistance of the MTJ.
  • FIG. 4(a) and 4(b) are application schematic diagrams of the single magnetoresistive TMR magnetic field sensor chip 101 and the relationship between the output voltage and the applied magnetic field, respectively.
  • the two terminals of the single magnetoresistive TMR magnetic field sensor chip 101 are the C terminal and the D terminal shown in FIG. 4(a), and the current source 402 and the single magnetoresistive TMR magnetic field sensor chip 101 form a loop.
  • the applied magnetic field reaches Hsat+ as shown in FIG. 4(b)
  • the resistance of the single magnetoresistive TMR magnetic field sensor chip 101 is the largest, and the potential difference between the C terminal and the D terminal of the TMR magnetic field sensor chip is the largest, which is recorded as Vmax;
  • the resistance of the TMR magnetic field sensor chip 101 is the smallest, and the potential difference between the C terminal and the D terminal of the TMR magnetic field sensor chip is the smallest, which is denoted as Vmin.
  • 5(a) and 5(b) are respectively another application principle diagram of the single magnetoresistive TMR magnetic field sensor chip 101 and a relationship between the output voltage and the applied magnetic field.
  • the two terminals of the single magnetoresistive TMR magnetic field sensor chip 101 are the E terminal and the F terminal shown in FIG. 5(a), and the voltage source 503, the conventional resistor 502, and the single reluctance TMR magnetic field sensor chip 101 constitute a series circuit.
  • the applied magnetic field reaches Hsat+ as shown in FIG. 5(b)
  • the resistance of the single magnetoresistive TMR magnetic field sensor chip 101 is the largest, and the potential difference between the E terminal and the F terminal of the single magnetoresistive TMR magnetic field sensor chip is the largest, which is recorded as Vmax1.
  • the resistance of the single magnetoresistive TMR magnetic field sensor chip 101 is the smallest, and the potential difference between the E terminal and the F terminal of the single magnetoresistive TMR magnetic field sensor chip is the smallest, For Vmin1.
  • the magnetic biasing structure in the present invention has various forms.
  • the magnetic biasing structure is composed of permanent magnets integrated on the chip between two adjacent MTJ strings.
  • the twelve MTJs 601 constitute an MTJ string 602, and the MTJs 601 are arranged along the sensing direction of the magnetic field sensor chip 101, wherein the center distance between two adjacent MTJs 601 is 1-20 micrometers, which is 6 micrometers in this embodiment.
  • the seven MTJ strings 602 are connected in series to form an MTJ unit 109, and the MTJ strings 602 are arranged in a direction perpendicular to the sensing direction of the magnetic field sensor chip 101, wherein the center distance 605 between adjacent two MTJ strings is 20 to 100 micrometers. In this embodiment it is 54 microns.
  • the five MTJ units 109 are connected in parallel to form a magnetoresistive element 108, and the center-to-center distance between two adjacent MTJ units 109 is 200-800 ⁇ m, which is 429 ⁇ m in this embodiment.
  • the MTJ unit 109 is arranged in a direction perpendicular to the sensing direction of the single magnetoresistive TMR magnetic field sensor chip 101.
  • an electrical connection conductor 604 composed of a conductive material effects electrical connection between two adjacent MTJ strings 602.
  • Fig. 7 shows the positional relationship of the permanent magnet 603 and the MTJ 601 in the first form.
  • the magnetization direction 703 of the permanent magnet 603 is perpendicular to the sensing direction of the magnetic field sensor chip, parallel to the long axis direction of the MTJ 601, that is, the direction of the easy magnetization axis, so that the hysteresis of the MTJ 601 can be reduced.
  • a permanent magnet 603 is placed on both sides of the MTJ 601 along the magnetization direction 703 of the permanent magnet 603.
  • the MTJ601 has an elliptical shape with a ratio of lengths of the major axis to the minor axis greater than 3.
  • the long axis 701 is the easy magnetization axis of the MTJ601, and the short axis 702 is the hard magnetization axis of the MTJ601.
  • the magnetic field generated by the magnetic excitation element at the permanent magnet 603 should be less than half of the coercive force of the permanent magnet 603 and less than 0.1T.
  • the MTJ 601 is composed of a magnetic free layer 801, a tunnel barrier layer 802, a pinned layer 803, and an antiferromagnetic layer 804.
  • MTJ601 long axis 805 The dimensions of the minor axis 806 are 10 microns and 1.5 microns, respectively.
  • the tunnel barrier layer 802 is typically composed of MgO or Al2O3 and constitutes the majority of the resistance of the MTJ601.
  • the exchange coupling of the antiferromagnetic layer 804 and the pinned layer 803 determines the magnetization direction of the pinned layer 803. In the present embodiment, the magnetization direction of the pinned layer 803 is parallel to the direction of the short axis 806.
  • the magnetization direction of the magnetic free layer 801 is affected by an external magnetic field, and the magnetization direction of the magnetic free layer 801 is parallel to the magnetization direction 703 of the permanent magnet 603 when no external magnetic field is applied.
  • the magnetization direction of the magnetic free layer 801 changes under the action of the banknote and the back magnet in the money detector head. According to the tunneling effect, the resistance of the MTJ601 also changes, and then the signal is converted. The detection of banknotes can be achieved.
  • the magnetic bias structure is composed of a magnetic thin film deposited on the MTJ, and twelve MTJ901s are connected in series to form an MTJ string 902, and the MTJ901 is arranged along the sensing direction of the magnetic field sensor chip, wherein adjacent The center distance between the two MTJs 901 is 1 to 20 microns, which is 6 microns in this embodiment.
  • the seven MTJ strings 902 are connected in series to form an MTJ unit 109, and the MTJ strings 902 are arranged in a direction perpendicular to the sensing direction of the magnetic field sensor chip, wherein the center distance 904 between the adjacent two MTJ strings 902 is 20-100 microns.
  • the five MTJ units 109 are connected in parallel to form a magnetoresistive element 108, which is arranged in a direction perpendicular to the sensing direction of the magnetic field sensor chip.
  • An electrical connection conductor 903 of electrically conductive material effects electrical connection between two adjacent MTJ strings 902.
  • the MTJ 901 is composed of a magnetic thin film 1001, a magnetic free layer 1002, a tunnel barrier layer 1003, a pinned layer 1004, and an antiferromagnetic layer 1005 constituting a magnetic bias structure.
  • the ratio of the length of the major axis to the minor axis of the MTJ901 is greater than 3 and the dimensions are 30 microns and 1.5 microns, respectively.
  • the magnetization direction of the magnetic film 1001 is perpendicular to the sensing direction of the single magnetoresistive TMR magnetic field sensor chip, parallel to the long axis direction of the MTJ 901, for reducing the hysteresis thereof.
  • the long axis direction of the MTJ 901 is its easy magnetization axis direction.
  • the tunnel barrier layer 1003 is usually composed of MgO or Al2O3 and constitutes most of the resistance of the MTJ901.
  • the exchange coupling of the antiferromagnetic layer 1005 and the pinned layer 1004 determines the magnetization direction of the pinned layer 1004.
  • the magnetic field generated by the magnetic excitation element at the magnetic film 1001 should be less than half of the coercive force of the magnetic film 1001 and less than 0.1T.
  • the magnetization direction of the pinned layer 1004 is parallel to the direction of the minor axis 1008.
  • the magnetization direction of the magnetic free layer 1002 is affected by the external magnetic field. When there is no external magnetic field, the magnetization direction of the magnetic free layer 1002 is parallel to the magnetization direction 1006 of the magnetic film 1001; when the banknote is close to the chip, in the banknote and the money detector head Under the action of the back magnet, the magnetization direction of the magnetic free layer 1002 will change, and the resistance of the MTJ901 also changes according to the tunneling effect. After the signal conversion, the banknote can be detected.
  • the third form is that the magnetic film 1001 in Fig. 10 can be replaced with an exchange working layer, and the MTJ thus constructed is as shown in Fig. 11, and the structure of the magnetoresistive unit composed of the method is the same as that of the magnetoresistive unit 109 of Fig. 9. .
  • the MTJ 1110 is composed of an exchange active layer 1100, a magnetic free layer 1103, a tunnel barrier layer 1104, a pinned layer 1105, and an antiferromagnetic layer 1106, wherein the exchange active layer 1100 is weakened by the antiferromagnetic layer 1101 and the antiferromagnetic layer 1101.
  • a coupled ferromagnetic layer 1102 is formed, and a ferromagnetic layer 1102 is located intermediate the magnetic free layer 1103 and the antiferromagnetic layer 1101.
  • MTJ In the elliptical shape, the ratio of the length of the major axis to the minor axis of the MTJ 1110 is greater than three, and the dimensions of the major axis 1107 and the minor axis 1108 in this embodiment are 30 micrometers and 1.5 micrometers, respectively.
  • the magnetization direction of the ferromagnetic layer 1102 is perpendicular to the sensing direction of the TMR magnetic field sensor chip, parallel to the long axis direction of the MTJ 1110, to reduce hysteresis.
  • the magnetization direction of the magnetic free layer 1103 is affected by the external magnetic field. When there is no external magnetic field, the magnetization direction of the magnetic free layer 1103 is parallel to the magnetization direction 1109 of the ferromagnetic layer 1102; when the banknote is close to the chip, the banknote and the money detector head are Under the action of the back magnet, the magnetization direction of the magnetic free layer 1103 will change. According to the tunneling effect, the resistance of the MTJ1110 also changes, and then the signal conversion can realize the detection of the banknote.
  • Figure 12 is a cross-sectional view of a magnetoresistive string showing the connection between the MTJs.
  • the lower electrode 1202 is located above the substrate 1204 and is electrically connected to the bottom of the MTJ1201, and the upper electrode 1203 is electrically connected to the top of the MTJ1201.
  • the upper and lower electrodes are alternately arranged along the direction of the sensing direction of the magnetic field sensor chip, and thereby constitute an electrical interconnection of the MTJ 1201 in the MTJ string, and the center-to-center spacing between two adjacent MTJs 1201 is 1205.
  • the invention also provides a money detector magnetic head manufactured by using the above single magnetoresistive TMR magnetic field sensor chip, and the magnetic head specifically comprises:
  • a signal processing circuit a magnetic excitation element, an output pin, a wiring board, and at least one of the above-described single magnetoresistive TMR magnetic field sensor chips.
  • the magnetic excitation component is mounted under the single magnetoresistive TMR magnetic field sensor chip for providing an excitation magnetic field to generate an applied magnetic field in the direction of the chip sensing direction; the single magnetoresistive TMR magnetic field sensor chip senses the applied magnetic field, and It is converted into an electrical signal; the signal processing circuit converts the electrical signal and passes it through the board to the output pin.
  • a plurality of single magnetoresistive TMR magnetic field sensor chips can be connected to form a sensor chip combination.
  • 2 is a schematic view showing a connection method of two or more single magnetoresistive TMR magnetic field sensor chips 101. Since each input and output terminal has two pads, the plurality of single magnetoresistive TMR magnetic field sensor chips 101 can be electrically interconnected by wire bonding, and 201, 202, 203 in the figure is used for Wire bonded interconnects.
  • the above sensor chip combination can be applied in the money detector magnetic head, and the area of the sensing area is larger than the sensing area of the single single magnetoresistive TMR magnetic field sensor chip, thereby increasing the scope of the banknote detection and improving the efficiency of banknote detection.

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  • General Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Measuring Magnetic Variables (AREA)
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  • Inspection Of Paper Currency And Valuable Securities (AREA)

Abstract

一种单磁阻TMR磁场传感器芯片（101）及验钞机磁头。其中单磁阻TMR磁场传感器芯片（101）安装在磁激励元件上方，芯片的感应方向与芯片表面平行，磁激励元件在芯片处产生的激励磁场的方向垂直于芯片表面，该芯片包括：基片（102）、沉积在基片（102）上的磁偏置结构、磁电阻元件（108）以及输入、输出接线端；磁电阻元件（108）由MTJ构成；磁电阻元件（108）的感应方向、MTJ的感应方向均与芯片的感应方向相同；磁偏置结构在芯片处产生的偏置磁场的方向垂直于芯片的感应方向。该芯片具有高灵敏度、高信噪比、小体积、高温度稳定性和高可靠性的特点。

Description

一种单磁阻TMR磁场传感器芯片及验钞机磁头
技术领域
本发明涉及磁场传感器领域，尤其是涉及一种单磁阻TMR磁场传感器芯片和基于此芯片制成的验钞机磁头。
背景技术
在日常生活中，验钞机磁头的应用非常广泛，如自动售货机、点钞机等设备中均需要验钞机磁头。目前主流的验钞机磁头技术中，使用的是以锑化铟为敏感材料的磁头，磁力线垂直于检测面，在纸币经过磁头时，磁场会发生变化，通过检测磁场的变化，实现这种纸币真伪的鉴别。但是这种磁头的灵敏度低、信噪比低、体积大、温度稳定性差，可靠性较差。
发明内容
本发明的目的在于提供一种单磁阻TMR磁场传感器芯片以及验钞机磁头，以提高灵敏度、信噪比、温度稳定性以及可靠性，减小磁头的体积。
本发明提供了一种单磁阻TMR磁场传感器芯片，包括：
一种单磁阻TMR磁场传感器芯片，安装在磁激励元件上方，该芯片的感应方向与芯片表面平行，磁激励元件在芯片处产生的激励磁场的方向垂直于芯片表面，单磁阻TMR磁场传感器芯片包括:
基片、沉积在基片上的磁偏置结构、磁电阻元件以及输入、输出接线端；
磁电阻元件由至少一个MTJ单元构成；
MTJ单元由至少一个MTJ串构成；
MTJ串由至少一个MTJ构成；
磁电阻元件的感应方向、MTJ的感应方向均与芯片的感应方向相同；
磁偏置结构在芯片处产生的偏置磁场的方向垂直于芯片的感应方向。
优选的，
磁电阻元件由至少两个MTJ单元并联或串联构成,MTJ单元沿着垂直或平行于单磁阻TMR磁场传感器芯片的感应方向排列，两个相邻MTJ单元之间的中心距为200~800 微米；
和/或;
MTJ单元由至少两个MTJ串并联或串联构成,MTJ串沿着垂直或平行于单磁阻TMR磁场传感器芯片的感应方向排列，两个相邻MTJ串之间的中心距为20-100 微米；
和/或；
MTJ串由至少两个MTJ并联或串联构成,MTJ沿着垂直或平行于单磁阻TMR磁场传感器芯片的感应方向排列，两个相邻MTJ之间的中心距为1-20微米。
优选的， MTJ的俯视形状呈椭圆形，其长轴与短轴的长度之比大于3，且MTJ的短轴平行于芯片的感应方向。
优选的，在没有外加磁场时，MTJ中自由层的磁化方向在磁偏置结构的作用下，平行于MTJ的长轴方向。
优选的，磁偏置结构为块状或层状，其材料为由Cr，Co，Pt，Pd，Ni或Fe组成的合金。
优选的，磁偏置结构由两个相邻MTJ串之间的永磁体构成；沿着永磁体的磁化方向，在MTJ的两侧均放置有永磁体；磁激励元件在永磁体处产生的磁场小于永磁体的矫顽力的一半，并且要小于0.1T。
优选的，磁偏置结构由沉积在MTJ上的磁性薄膜构成；磁激励元件在磁性薄膜处产生的磁场小于磁性薄膜的矫顽力的一半，并且要小于0.1T。
优选的，磁偏置结构由沉积在MTJ上的交换作用层构成，交换作用层包括反铁磁层和与反铁磁层弱耦合的铁磁层。
优选的，输入、输出接线端均至少包括两个引线键合焊盘，各引线键合焊盘位于单磁阻TMR磁场传感器芯片的两端。
优选的，多个单磁阻TMR磁场传感器芯片之间通过引线键合焊盘电连接，形成传感器芯片组合，传感器芯片组合的感应区域面积大于单一单磁阻TMR磁场传感器芯片的感应区域面积。
优选的，引线键合焊盘的长度为15-2000微米，宽度为15-1000 微米。
优选的，基片上设置有电连接导体，用于实现电连接，电连接导体的宽度不小于10 微米。
优选的，单磁阻TMR磁场传感器芯片的长度为500-3000微米，宽度为20-1500微米。
本发明还对应提供了一种验钞机磁头，该磁头包括：
至少一个如上面任一项的单磁阻TMR磁场传感器芯片、信号处理电路、磁激励元件、输出引脚以及线路板；
磁激励元件安装在单磁阻TMR磁场传感器芯片的下方，用于提供一个激励磁场，使得在被测空间产生一个在芯片感应方向上的外加磁场；
单磁阻TMR磁场传感器芯片感应外加磁场，并将其转化成电信号；
信号处理电路对电信号进行转换，通过线路板传递到输出引脚。
根据本发明提供的具体实施例，本发明公开了以下技术效果：
本发明提供了一种感应方向与芯片表面平行的单磁阻TMR磁场传感器芯片，磁激励元件在芯片处产生的激励磁场的方向垂直于芯片表面，且芯片的磁电阻元件由MTJ构成；磁电阻元件的感应方向、所述MTJ的感应方向均与所述芯片的感应方向相同；磁偏置结构在芯片处产生的偏置磁场的方向垂直于芯片的感应方向。本发明的芯片具有高灵敏度、高信噪比、小体积、高温度稳定性和高可靠性。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1为单磁阻TMR磁场传感器芯片的示意图；
图2为两个或两个以上单磁阻TMR磁场传感器芯片之间的连接方式的示意图；
图3（a）为MTJ的结构示意图；
图3（b）为电阻值与外加磁场之间的关系曲线；
图4（a）为单磁阻TMR磁场传感器芯片的一种应用原理图；
图4（b）为与图4（a）对应的传感器芯片的输出电压与外加磁场之间的关系曲线；
图5（a）为单磁阻TMR磁场传感器芯片的另一种应用原理图；
图5（b）为与图5（a）对应的传感器芯片的输出电压与外加磁场之间的关系曲线；
图6为第一种磁偏置方法组成的MTJ单元的示意图；
图7为第一种磁偏置方法中MTJ与相邻的永磁体的位置关系；
图8为第一种磁偏置方法中MTJ的结构示意图；
图9为第二种磁偏置方法组成的MTJ单元的示意图；
图10为第二种磁偏置方法中的MTJ的结构示意图
图11为第三种磁偏置方法中的MTJ的结构示意图
图12为多个MTJ之间的连接方式的示意图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本发明实施例1提供了一种单磁阻TMR（Tunnel magnetoresistance，隧道磁电阻） 磁场传感器芯片。图1是单磁阻TMR磁场传感器芯片101的示意图。在实际应用中，该芯片的长度可以为500-3000微米，宽度可以为20-1500微米，但不限于以上尺寸。芯片中所有部件都位于基片102上，基片102可以由硅、陶瓷、树脂等可以制作集成电路的材料构成。本发明中采用的是硅基板。磁电阻元件108由一个磁性隧道结MTJ（Magnetic Tunnel Junction）单元109构成，或者由至少两个MTJ单元109串联或并联构成。图1中示出的磁电阻元件108由五个MTJ单元109并联构成。一个MTJ单元109由一个MTJ串构成，或由两个以上的MTJ串并联或串联构成。每个MTJ串由一个MTJ构成或由两个以上MTJ并联或串联构成。单磁阻TMR磁场传感器芯片和常规电阻器一样，具有两个端子，分别为输入接线端和输出接线端，且每个端子都至少有两个引线键合焊盘。引线键合焊盘还可以用于多个单磁阻TMR磁场传感器芯片之间的电连接，这些芯片形成传感器芯片组合，传感器芯片组合的感应区域面积大于单一单磁阻TMR磁场传感器芯片的感应区域面积。
图1中的104和105是单磁阻TMR磁场传感器芯片的一个端子的两个引线键合焊盘，106和107是单磁阻TMR磁场传感器芯片的另一个端子的两个引线键合焊盘。优选地，引线键合焊盘104—107的长度为15-2000微米，宽度为15-1000微米。焊盘和焊盘之间、焊盘和磁电阻元件之间用电连接导体103相连，电连接导体103是由高电导率的材料制成的，其宽度不小于10微米。
上述芯片安装在磁激励元件上方，磁激励元件在芯片处产生的激励磁场的方向垂直于芯片表面。该芯片还包括沉积在基片上的磁偏置结构（图中未示出）。该磁偏置结构可为块状或层状，所用材料可以是由Cr，Co，Pt，Pd，Ni或Fe组成的合金。
磁偏置结构在芯片处产生的偏置磁场的方向垂直于芯片的感应方向，以使磁电阻元件工作在线性区并减小MTJ的磁滞。本发明中，芯片的感应方向与芯片表面平行，磁电阻元件的感应方向、MTJ的感应方向均与芯片的感应方向相同。
本发明中使用了MTJ作为感应元件，其具有高灵敏度、尺寸小、成本低、功耗低的优点。MTJ的具体结构如图3（a）所示，隧道层303在铁磁性自由层302和磁性被钉扎层304中间，磁性被钉扎层304的磁化方向305垂直于磁偏置结构提供的偏置磁场方向。在偏置磁场的作用下，如果没有外加磁场，铁磁性自由层302的磁化方向与偏置磁场的方向相同。当有外加磁场时，铁磁性自由层302的磁化方向将跟随外加磁场发生改变。MTJ的两个端子A端和B端之间宏观上表现出电阻的特性，并且电阻值会随着铁磁性自由层302的磁化方向的变化而变化：当铁磁性自由层302的磁化方向与磁性被钉扎层304的磁化方向305平行，如箭头307所示，且铁磁性自由层302被磁化到饱和，A端和B端之间的电阻最小，记为Rmin，此时的外加磁场记为Hsat-；当铁磁性自由层302的磁化方向与磁性被钉扎层304的磁化方向305反平行，如箭头306所示，且铁磁性自由层302被磁化到饱和，A端和B端之间的电阻最大，记为Rmax，此时的外加磁场记为Hsat+，如图3（b）所示。MTJ的阻值随着外加磁场在Rmin和Rmax之间线性变化。因此，可以通过MTJ阻值的变化实现对外加磁场的测量。
图4（a）和4（b）分别是单磁阻TMR磁场传感器芯片101的应用原理图以及输出电压与外加磁场之间的关系曲线。单磁阻TMR磁场传感器芯片101的两个接线端为图4（a）中所示的C端和D端，电流源402与单磁阻TMR磁场传感器芯片101构成一个回路。当外加磁场达到如图4（b）中所示的Hsat+时，单磁阻TMR磁场传感器芯片101的电阻最大，此时TMR磁场传感器芯片的C端和D端的电势差最大，记为Vmax；当外加磁场达到如图4（b）中所示的的Hsat-时，TMR磁场传感器芯片101的电阻最小，此时TMR磁场传感器芯片的C端和D端的电势差最小，记为Vmin。
图5（a）和5（b）分别是是单磁阻TMR磁场传感器芯片101的另一个应用原理图以及输出电压与外加磁场之间的关系曲线。单磁阻TMR磁场传感器芯片101的两个接线端为图5（a）中所示的E端和F端，电压源503、常规电阻502和单磁阻TMR磁场传感器芯片101构成一个串联回路。当外加磁场达到如图5（b）中所示的Hsat+时，单磁阻TMR磁场传感器芯片101的电阻最大，此时单磁阻TMR磁场传感器芯片的E端和F端的电势差最大，记为Vmax1；当外加磁场达到如图5（b）中所示的Hsat-时，单磁阻TMR磁场传感器芯片101的电阻最小，此时单磁阻TMR磁场传感器芯片的E端和F端的电势差最小，记为Vmin1。
本发明中的磁偏置结构具有多种形式。
参见图6，在第一种形式中，磁偏置结构由相邻两个MTJ串之间的集成在芯片上的永磁体构成。十二个MTJ601构成一个MTJ串602，MTJ601沿着磁场传感器芯片101的感应方向排列，其中相邻的两个MTJ601之间的中心距为1-20微米，本实施例中为6微米。七个MTJ串602串联构成一个MTJ单元109，MTJ串602沿着垂直于磁场传感器芯片101的感应方向的方向排列，其中相邻的两个MTJ串之间的中心距605为20~100微米，本实施例中为54微米。五个MTJ单元109并联构成一个磁电阻元件108，相邻的两个MTJ单元109之间的中心距为200-800微米，本实施例中为429微米。MTJ单元109沿着垂直于单磁阻TMR磁场传感器芯片101的感应方向的方向排列。在相邻两个MTJ串602之间，具有集成在芯片上的永磁体603；由导电材料构成的电连接导体604实现相邻的两个MTJ串602之间的电连接。
图7展示了第一种形式中的永磁体603和MTJ601的位置关系。永磁体603的磁化方向703垂直于磁场传感器芯片的感应方向，平行于MTJ601的长轴方向即易磁化轴方向，这样可以减小MTJ601的磁滞。沿着永磁体603的磁化方向703上，在MTJ601的两侧均放置有永磁体603。MTJ601为椭圆形状，长轴和短轴的长度之比大于3。长轴701即为MTJ601的易磁化轴，短轴702即为MTJ601的难磁化轴。为了使永磁体603不被磁激励元件磁化而导致失效，磁激励元件在永磁体603处产生的磁场应小于永磁体603的矫顽力的一半，并且要小于0.1T。
图8是图7中的MTJ601的结构示意图，MTJ601由磁性自由层801、隧道势垒层802、被钉扎层803和反铁磁层804构成。MTJ601的长轴805 和短轴806的尺寸分别为10微米和1.5微米。隧道势垒层802通常由MgO或Al2O3构成，并构成了MTJ601的绝大多数电阻。反铁磁层804和被钉扎层803的交换耦合作用决定了被钉扎层803的磁化方向。本实施例中，被钉扎层803的磁化方向平行于短轴806的方向。磁性自由层801的磁化方向受外界磁场的影响，在没有外加磁场时，磁性自由层801的磁化方向平行于永磁体603的磁化方向703。当有纸币靠近芯片时，在纸币以及验钞磁头中的背磁体的作用下，磁性自由层801的磁化方向将发生变化，根据隧穿效应，MTJ601的电阻也随之变化，再经过信号转化，即可实现纸币的检测。
参见图9，在第二种形式中，磁偏置结构由沉积在MTJ上的磁性薄膜构成，十二个MTJ901串联构成一个MTJ串902，MTJ901沿着磁场传感器芯片的感应方向排列，其中相邻的两个MTJ901之间的中心距为1~20微米，本实施例中为6微米。七个MTJ串902串联构成一个MTJ单元109，MTJ串902沿着垂直于磁场传感器芯片的感应方向的方向排列，其中相邻的两个MTJ串902之间的中心距904为20-100微米，本实施例中为54微米。五个MTJ单元109并联构成一个磁电阻元件108，MTJ单元109沿着垂直于磁场传感器芯片的感应方向的方向排列。由导电材料构成的电连接导体903实现相邻的两个MTJ串902之间的电连接。
图10是图9中的MTJ901的结构示意图，MTJ901由构成磁偏置结构的磁性薄膜1001、磁性自由层1002、隧道势垒层1003、被钉扎层1004和反铁磁层1005构成。MTJ901的长轴和短轴的长度之比大于3，尺寸分别为30微米和1.5微米。磁性薄膜1001的磁化方向垂直于单磁阻TMR磁场传感器芯片的感应方向、平行于MTJ901的长轴方向，用于减小其磁滞。根据形状各向异性，MTJ901的长轴方向即其易磁化轴方向。隧道势垒层1003通常由MgO或Al2O3构成，并构成了MTJ901的绝大多数电阻。反铁磁层1005和被钉扎层1004的交换耦合作用决定了被钉扎层1004的磁化方向。为了使磁性薄膜1001不被磁激励元件磁化而导致失效，磁激励元件在磁性薄膜1001处产生的磁场应小于磁性薄膜1001的矫顽力的一半，并且要小于0.1T。
本实施例中，被钉扎层1004的磁化方向平行于短轴1008的方向。磁性自由层1002的磁化方向受外界磁场的影响，在没有外加磁场时，磁性自由层1002的磁化方向平行于磁性薄膜1001的磁化方向1006；当有纸币靠近芯片时，在纸币以及验钞磁头中的背磁体的作用下，磁性自由层1002的磁化方向将发生变化，根据隧穿效应，MTJ901的电阻也随之变化。再经过信号转化，即可实现纸币的检测。
第三种形式是：图10中的磁性薄膜1001可以用交换作用层代替，由此构成的MTJ如图11所示，由该方法组成的磁电阻单元结构与图9中磁电阻单元109的相同。MTJ1110由交换作用层1100、磁性自由层1103、隧道势垒层1104、被钉扎层1105、反铁磁层1106构成，其中交换作用层1100由反铁磁层1101和与反铁磁层1101弱耦合的铁磁层1102构成，铁磁层1102位于磁性自由层1103和反铁磁层1101中间。MTJ 为椭圆形状，MTJ1110的长轴和短轴的长度之比大于3，本实施例中长轴1107和短轴1108的尺寸分别为30微米和1.5微米。在与反铁磁层1101的交换耦合作用下，铁磁层1102的磁化方向垂直于TMR磁场传感器芯片的感应方向、平行于MTJ1110的长轴方向，以减小磁滞。磁性自由层1103的磁化方向受外界磁场的影响，在没有外加磁场时，磁性自由层1103的磁化方向平行于铁磁层1102的磁化方向1109；当有纸币靠近芯片时，在纸币以及验钞磁头中的背磁体的作用下，磁性自由层1103的磁化方向将发生变化，根据隧穿效应，MTJ1110的电阻也随之变化，再经过信号转化，即可实现纸币的检测。
图12是一个磁电阻串的截面图，展示了MTJ之间的连接方式。下电极1202位于基片1204上方，与MTJ1201的底部电连接，上电极1203与MTJ1201的顶部电连接。上电极和下电极沿着磁场传感器芯片的感应方向的方向交替排列，并由此构成MTJ串中MTJ1201的电气互连，相邻两个MTJ1201之间的中心间距为1205。
本发明还提供了一种应用上述单磁阻TMR磁场传感器芯片制成的验钞机磁头，该磁头具体包括：
信号处理电路、磁激励元件、输出引脚、线路板以及至少一个上述的单磁阻TMR磁场传感器芯片。
磁激励元件安装在单磁阻TMR磁场传感器芯片的下方，用于提供一个激励磁场，使得在被测空间产生一个在芯片感应方向上的外加磁场；单磁阻TMR磁场传感器芯片感应外加磁场，并将其转化成电信号；信号处理电路对电信号进行转换，通过线路板传递到输出引脚。
为增加感应区域的面积，可将多个单磁阻TMR磁场传感器芯片连接起来，组成形成传感器芯片组合。图2是两个及两个以上单磁阻TMR磁场传感器芯片101的连接方法示意图。由于每个输入、输出接线端子都具有两个焊盘，使多个单磁阻TMR磁场传感器芯片101可以用引线键合的方式实现电气互连，图中的201，202，203即为用于引线键合的互连线。
上述传感器芯片组合可应用在验钞磁头中，感应区域的面积大于单一的单磁阻TMR磁场传感器芯片的感应面积，从而增大验钞范围，提高验钞效率。
以上对根据本发明实施的一种单磁阻TMR磁场传感器芯片和基于此芯片制成的验钞机磁头，进行了详细介绍，本文中应用了具体个例对本发明的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本发明的方法及其核心思想；同时，对于本领域的一般技术人员，依据本发明的思想，在具体实施方式及应用范围上均会有改变之处。综上所述，本说明书内容不应理解为对本发明的限制。

Claims (14)

1. 一种单磁阻TMR磁场传感器芯片，安装在磁激励元件上方，该芯片的感应方向与芯片表面平行，磁激励元件在芯片处产生的激励磁场的方向垂直于芯片表面，其特征在于，
所述单磁阻TMR磁场传感器芯片包括:
基片、沉积在基片上的磁偏置结构、磁电阻元件以及输入接线端和输出接线端；
磁电阻元件由至少一个MTJ单元构成；
所述MTJ单元由至少一个MTJ串构成；
所述MTJ串由至少一个MTJ构成；
所述磁电阻元件的感应方向、所述MTJ的感应方向均与所述芯片的感应方向相同；
所述磁偏置结构在所述芯片处产生的偏置磁场的方向垂直于所述芯片的感应方向。
2. 根据权利要求1所述的单磁阻TMR磁场传感器芯片，其特征在于，
所述磁电阻元件由至少两个MTJ单元并联或串联构成,所述MTJ单元沿着垂直或平行于所述单磁阻TMR磁场传感器芯片的感应方向排列，两个相邻MTJ单元之间的中心距为200-800微米；和/或
所述MTJ单元由至少两个MTJ串并联或串联构成,所述MTJ串沿着垂直或平行于所述单磁阻TMR磁场传感器芯片的感应方向排列，两个相邻MTJ串之间的中心距为20-100 微米；和/或
所述MTJ串由至少两个MTJ并联或串联构成,所述MTJ沿着垂直或平行于所述单磁阻TMR磁场传感器芯片的感应方向排列，两个相邻MTJ之间的中心距为1-20微米。
3. 根据权利要求1所述的TMR磁场传感器芯片，其特征在于， 所述MTJ的俯视形状呈椭圆形，其长轴与短轴的长度之比大于3，且所述MTJ的短轴平行于所述芯片的感应方向。
4. 根据权利要求3所述的单磁阻TMR磁场传感器芯片，其特征在于，在没有外加磁场时，所述MTJ中自由层的磁化方向在所述磁偏置结构的作用下，平行于所述MTJ的长轴方向。
5. 根据权利要求1所述的单磁阻TMR磁场传感器芯片，其特征在于，所述磁偏置结构为块状或层状，其材料为由Cr，Co，Pt，Pd，Ni或Fe组成的合金。
6. 根据权利要求1所述的单磁阻TMR磁场传感器芯片，其特征在于，所述磁偏置结构由两个相邻MTJ串之间的永磁体构成；
沿着所述永磁体的磁化方向，在所述MTJ的两侧均放置有所述永磁体；
所述磁激励元件在所述永磁体处产生的磁场小于所述永磁体的矫顽力的一半，并且要小于0.1T。
7. 根据权利要求1所述的单磁阻TMR磁场传感器芯片，其特征在于，所述磁偏置结构由沉积在所述MTJ上的磁性薄膜构成；所述磁激励元件在所述磁性薄膜处产生的磁场小于所述磁性薄膜的矫顽力的一半，并且要小于0.1T。
8. 根据权利要求1所述的单磁阻TMR磁场传感器芯片，其特征在于，所述磁偏置结构由沉积在所述MTJ上的交换作用层构成，所述交换作用层包括反铁磁层和与反铁磁层弱耦合的铁磁层。
9. 根据权利要求1所述的单磁阻TMR磁场传感器芯片，其特征在于，所述输入、输出接线端均至少包括两个引线键合焊盘，各引线键合焊盘位于所述单磁阻TMR磁场传感器芯片的两端。
10. 根据权利要求9所述的单磁阻TMR磁场传感器芯片，其特征在于，多个单磁阻TMR磁场传感器芯片之间通过所述引线键合焊盘电连接，形成传感器芯片组合，所述传感器芯片组合的感应区域面积大于单一所述单磁阻TMR磁场传感器芯片的感应区域面积。
11. 根据权利要求9所述的单磁阻TMR磁场传感器芯片，其特征在于，所述引线键合焊盘的长度为15-2000微米，宽度为15-1000 微米。
12. 根据权利要求1所述的单磁阻TMR磁场传感器芯片，其特征在于，所述基片上设置有电连接导体，用于实现电连接，所述电连接导体的宽度不小于10 微米。
13. 根据权利要求1所述的单磁阻TMR磁场传感器芯片，其特征在于，所述单磁阻TMR磁场传感器芯片的长度为500-3000微米，宽度为20-1500微米。
14. 一种验钞机磁头，其特征在于，所述磁头包括：
至少一个如权利要求1-13中任一项所述的单磁阻TMR磁场传感器芯片、信号处理电路、磁激励元件、输出引脚以及线路板；
所述磁激励元件安装在所述单磁阻TMR磁场传感器芯片的下方，用于提供一个激励磁场，使得在被测空间产生一个在芯片感应方向上的外加磁场；
所述单磁阻TMR磁场传感器芯片感应外加磁场，并将外加磁场转化成电信号；
所述信号处理电路对电信号进行转换，通过所述线路板传递到所述输出引脚。
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