JP2016003866A - Gmi element for z-axis, and ultrathin three-dimensional gmi sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop an ultrasmall/ultrathin high-performance three-dimensional GMI sensor by solving a trade-off problem between a wire length and a magnetic field detection performance in the GMI sensor.SOLUTION: Solder joint and an assembly method such as a conductive post are combined with a fine coil, a combination unit element of a right-handed coil and a left-handed coil, a GMI element having a size of 0.2 mm and an integrated circuit chip, to thereby achieve simultaneously detectability improvement of a three-dimensional GMI sensor and micro-sizing.

Description

The present invention improves the magnetic field detection performance of a three-dimensional type GMI sensor used such as an orientation sensor by assembling three GMI elements of the X axis, the Y axis, and the Z axis on one integrated substrate, and at the same time, The present invention relates to a technique that makes it possible to reduce the thickness and the size.

The azimuth sensor measures the geomagnetic vector by combining three magnetic sensor elements of the X axis, Y axis and Z axis and an integrated circuit, and calculates the azimuth from the measured value. It is widely used as a real-time three-dimensional azimuth meter in combination with an accelerometer and vibration gyro sensor in smart phones, tablets, remote controls for Internet TV, motion games, motion capture, etc. In recent years, these devices have become more sensitive. In addition, there is a strong demand for downsizing and thinning along with low noise and wide measurement range.

In particular, along with the reduction in the thickness of smart phones, the height of the orientation sensor has been reduced from 40 mm to 40 mm or less, from the conventional 1.0 mm to 0.6 mm or less, and the size has been reduced from 50 mm to 1.5 mm square or less from the conventional 2.0 mm square. The above miniaturization is demanded. Therefore, a thickness of 0.2 mm or less is also required for a three-dimensional magnetic field detection element. Also, in terms of magnetic field detection performance, the noise is required to increase by 4 times from 2 mG or less to 0.5 mG or less in standard deviation, and from 12 G to 48 G for the measurement range.

In the azimuth sensor, a Hall element, an MR element, a GMR element, an MI (abbreviation of magneto-impedance) element, a GMI (giant-magneto-impedance element), or the like is used as a magnetic field detection element. In order to measure the strength of the magnetic field vector components Hx, Hy, and Hz in the X-axis, Y-axis, and Z-axis directions, measurement is performed using three elements, that is, the X-axis element, the Y-axis element, and the Z-axis element.

Hall element type azimuth sensors can meet size requirements, but have the disadvantage that noise is too large for demands of standard deviation of around 10mG and less than 1mG, improving Hall sensor sensitivity and reducing noise This is difficult in principle. In the MI element type azimuth sensor, the height of the Z-axis element is as high as 0.6 mm. Since the element length and the magnetic field detection performance are in a trade-off relationship, it is difficult to reduce the height.

On the other hand, a three-dimensional integrated element in which an MI element and a magnetic material are combined is disclosed in Patent Document 1, but the force that changes the Z-axis direction magnetic field in the plane direction by the permalloy mandrel is extremely weak. Therefore, a long and large permalloy mandrel is required, the thickness of the integral element is 0.5 mm or more, and the sensor thickness cannot be reduced. At present, many developments as described above have been made in order to simultaneously realize the magnetic field detection performance of the three-dimensional azimuth sensor and the downsizing / thinning of the sensor, but it has not yet been realized.

The detection principle of the MI sensor, which is an ultra-sensitive micro magnetic sensor, is a sensor that measures a magnetic field from a change in impedance by applying high-frequency current to an amorphous wire that is a magnetic sensitive body. Alternatively, there are two types of detection methods: a type in which a detection coil is wound around a wire, a pulse current is applied to the wire, a spin wave is generated on the surface of the wire, and a magnetic field is measured with a detection coil voltage generated at that time. Here, the former is called an MI (Magneto-Impedance) sensor, and the latter is called a GMI sensor. In addition, different scientific views on the principle of this sensor and names such as a high-frequency carrier sensor or a vertical FG sensor have been proposed. The present invention is based on the GMI sensor detection method.

Japanese Patent No. 4626728

The present inventor has tried to solve the problem of the trade-off between the magnetic field detection performance of the three-dimensional GMI sensor and the miniaturization and ultrathinning for many years. The issues that have been clarified during this process are described below.
The detection principle of the GMI sensor is that a detection coil is wound around an amorphous wire, which is a magnetic sensitive body, a pulse is applied to the wire, a spin wave is generated on the surface of the wire, and a detection voltage generated at that time is detected by the detection coil. .

Therefore, if the length of the amorphous wire as the magnetic detecting body is shortened, the demagnetizing field acting on the wire becomes stronger and the number of coil turns is reduced, and the detection performance of the sensor is greatly lowered.
In order to improve the magnetic field detection performance of this sensor, it is necessary to increase the number of coil turns significantly by reducing the coil pitch. However, when the number of turns of the coil is increased, the coil resistance, the parasitic capacitance of the coil, and the parasitic voltage due to pulse energization increase, and the detection voltage proportional to the magnetization decreases. As a result, the improvement of the magnetic field detection performance was not seen. .

Next, regarding the miniaturization and ultrathinning, the size of the current three-dimensional GMI sensor (orientation sensor) is 2 × 2 × 1.0 mm. The integrated circuit chip has a size of about 2 square mm or less and a thickness of 0.2 mm. The thickness of the sensor is determined by the circuit board, integrated circuit chip, GMI element thickness, the height of the Z-axis GMI element, the wire bonding height, the resin mold, and the like. In the method of connecting the three components of the GMI element, the integrated circuit chip, and the sensor substrate by wire bonding and finally resin packaging, the sensor thickness and size cannot be sufficiently reduced.

Therefore, first of all, the miniaturization of coil pitch and countermeasures against detection voltage, X-axis, Y-axis and Z-axis ultra-compact GMI elements, especially Z-axis GMI elements with a height of 0,2 mm, were devised. The sensor thickness is determined by devising a method of combining the chip directly to the chip without wire bonding, and combining the connection method of removing the circuit board and directly connecting the integrated circuit chip electrode and the external electronic circuit board. Therefore, it is required to develop a technique capable of reducing the thickness to the total thickness of the integrated circuit chip.

In view of the above technical background, the present invention combines three micro GMI elements of the X axis, Y axis and Z axis and an integrated circuit chip to improve the magnetic field detection performance and reduce the thickness of the sensor to 0. A technique for reducing the size to 5 mm or less is provided.

In order to solve the above-mentioned problems, the present inventor reduced the coil pitch of the GMI element, measures for detecting voltage by miniaturization, GMI element design, electrode position, connection method instead of wire bonding, and GMI element on the integrated circuit surface. As a result of multidimensional examination of the method of connecting the integrated circuit chip with a convex surface and the electronic circuit board by being placed above, the present invention has been achieved.

First, in order to increase the number of coil turns by miniaturizing the coil pitch, a magnetic wire as a magnetic sensitive body and a coil formed by winding it around the electrode wiring board are composed of a concave coil lower part and a convex coil upper part. And a three-layer structure of the joint portion, and the coil and the magnetic wire are shielded by an insulating material. With this three-layer structure, a technique for reducing the coil pitch from 30 μm to 5 μm has been devised, and the number of coil turns can be greatly increased even if the wire length is shortened.

Next, the element that controls the thickness of the sensor has been the height of the Z-axis element which is about 0.6 mm. This is because the magnetic field detection performance depends on the wire length, and if the wire length is shortened, the number of coil turns is also reduced and the magnetic field detection power is extremely reduced. By devising the above-described coil pitch miniaturization technology, the number of coil turns was greatly increased, and a Z-axis GMI with a wire length of 0.2 mm or less and an element height of 0.2 mm or less was devised.

Furthermore, a technique has been devised for canceling the parasitic voltage by combining two coils of a left-handed coil type and a right-handed coil type against a parasitic voltage accompanying an increase in the number of coil turns. In a GMI element that detects a change in magnetization due to a spin wave, which is an ultra-micro phenomenon, it is important to increase the number of turns of the coil. However, the parasitic voltage also increases with this, so there are two types of left-handed and right-handed coils. A unit that combines two coils is the basic unit. Therefore, in the present invention, this basic unit is referred to as a GMI element unit.

For coil resistance and parasitic capacitance of the coil, IR drop (voltage drop) due to coil resistance is not directly input to the sample-and-hold circuit so far but via a pulse-compatible buffer circuit.
Devised to suppress However, in an actual circuit, a small parasitic capacitance exists in a coil, an electrode, a wire bonding wiring, etc., and a current flows through the coil via the parasitic capacitance, thereby causing a voltage drop. The remaining parasitic capacitance was reduced to a level where the voltage drop could be ignored by reducing the electrode size and switching from wire bonding wiring to solder connection.

Specifically, the structure of the Z-axis GMI element is such that one or a plurality of GMI element units each including a right-handed coil and a left-handed coil having a fine coil pitch are wound around two magnetic wires. It consists of electrodes, and the connection between the electrodes and terminals is made by connecting two wire electrodes and wire terminals in series so that the pulse current flows through the wires in the opposite direction, and the two coil electrodes and coil terminals are output to the detection coil. The wiring structure was connected in series so that the voltage had a reverse polarity.

The electrodes of the Z-axis GMI element are arranged on the mounting surface side so that when the element plane is mounted on the surface of the integrated circuit chip, the electrodes of the integrated circuit chip and the GMI element can be joined with solder. It was set as the structure to arrange.

Next, in order to make it possible to install the three GMI elements on the upper surface of the integrated circuit chip (from 1 mm square to 1.5 mm square), the size was set to an ultra-small size of about 0.2 mm square. The typical size is the same for the X-axis and the Y-axis and is 0.2 × 0.2 × 0.2 mm (thickness 0.2 mm). For the Z-axis, it is 0.2 × 0.3 × 0.2 mm (height 0.2 mm).

The X-axis and Y-axis GMI elements have the same structure and the same size as the Z-axis element GMI element unit. The four electrodes are arranged so as to be symmetric with respect to the vertical and horizontal directions of the element, and when the element plane and the integrated circuit chip face each other and the electrodes are joined by soldering, the balance of the fixing and maintaining force is balanced. Secured.

Although the thickness of the sensor was increased by wire bonding, the thickness of the sensor was reduced by directly soldering the electrodes of both the GMI element and the integrated circuit chip.

Further, the connection between the integrated circuit chip and the external circuit board is performed by attaching a conductive material post having the same thickness as the height of the GMI element to the external connection electrode on the integrated circuit chip. Finally, resin molding was performed, and the electrode surface was polished and flattened. Then, solder was attached to the post electrode to form an electrode.
As a result, it has become possible to manufacture a small and thin three-dimensional GMI sensor of 1.2 × 1.2 × 0.4 mm from the conventional size of 2 × 2 × 1 mm.

In terms of performance, the number of coil turns is increased using fine coils, the parasitic voltage created by the pulse current is removed using right-handed and left-handed coils to improve the SN ratio and reduce noise, and the coil on the element side By reducing the parasitic capacitance of the coil by minimizing the electrode size and at the same time omitting wire bonding, and by directly inputting the coil voltage to the pulse-compatible buffer circuit, the IR due to the increased resistance due to the miniaturization of the coil Suppressing the drop (voltage drop) realizes a significant increase in detection power. Specifically, the noise was improved from 2 mG to 0.5 mG in standard deviation, and the measurement range was improved from ± 12 G to ± 48 G.

As described above, the ultra-thin three-dimensional GMI sensor is composed of a pulse-corresponding buffer circuit and the like for miniaturization of the coil pitch, cancellation of the parasitic voltage due to the increase in the number of coil turns, and parasitic capacitance of the coil. It can be realized for the first time by the present invention that combines a thin Z-axis GMI element and an assembly method that does not increase the sensor thickness by utilizing elemental technology.

In a three-dimensional azimuth meter, improvement in both characteristics of magnetic field detection power and ultra-thinness is required, but both are difficult to realize because of a trade-off relationship. The present invention provides a coil pitch miniaturization, a combination of right-handed and left-handed coils, electrode placement that enables soldering, adoption of a post structure attached to a sensor and an external electronic circuit board, and a pulse-compatible buffer circuit. Organically combining new technologies such as signal processing, and succeeded in realizing an ultra-thin three-dimensional azimuth meter without compromising magnetic field detection performance. To ultra-thin mobile terminals such as smart phones and wearable computers It is extremely useful in the industry that makes it possible to mount.

Wiring diagram of GMI element for Z axis according to embodiment 1 Wiring diagram of X-axis and Y-axis GMI elements according to Example 2 Assembly drawing of 3D GMI sensor according to embodiment 2 Circuit diagram of analog signal processing according to embodiment 2 Electronic circuit diagram of sensor according to embodiment 2

The present invention will be described in more detail with reference to embodiments of the invention.
The Z-axis GMI element according to the first embodiment includes one, a plurality, and four GMI element units each including two magnetic wires and a right-handed coil and a left-handed coil each having a fine coil pitch wound on the element plane. As for the connection between the electrode and the terminal, two wire electrodes and four wire terminals are connected in series so that the pulse current flows in the opposite direction to the wire, and the two coil electrodes and the four terminals are connected. It has a wiring structure in which the coil terminals are connected in series so that the detection coil output voltage is inverted, and consists of a GMI element unit with a wire length of 0.2 mm or less, and four electrodes are integrated into this element plane. The electrodes of the integrated circuit chip and the GMI element are arranged in a line on the mounting surface side so that they can be joined together by solder when mounted upright on the circuit chip surface. Height below 0.20 mm, yet is characterized in that the number of coil turns has more than 30 times.

The parasitic voltage induced by the pulse current increases in proportion to the number of coil turns. As a countermeasure, if a pulse current flows in the positive direction through the right-handed coil, a pulse current flows in the negative direction through the left-handed coil, and then the output voltage polarities of the two detection coils are reversed and connected in series, The output voltage proportional to is the same sign, and the output connected in series is doubled. At the same time, the parasitic voltage generated by the circumferential magnetic field generated by pulse energization has a different sign, and the output can be canceled and lost. A parasitic voltage is also generated due to the potential difference between the wire potentials at the two coil terminal extraction positions. However, the coil terminal is installed at a position where the potentials are approximately equal to each other to reduce the parasitic voltage generated during pulse energization.

The measurement range can be adjusted from ± 3 G to ± 200 G by controlling the length of the magnetic wire as short as 0.2 mm or less. The detection power can be improved by reducing the coil pitch in the range of 1 μm to 20 μm and increasing the total number of coil turns by increasing the number of GMI element units even when the wire length is shortened. . At this time, since the resistance of the coil increases from 1Ω of the existing GMI element to 100Ω to 1KΩ, it is necessary to detect the coil voltage with a pulse-compatible buffer circuit. Regarding the parasitic capacitance of the coil, it is desirable to reduce the parasitic capacitance by omitting wire bonding and reducing the electrode size.

The Z-axis GMI element is mounted upright on the surface of the integrated circuit chip and fixed with an adhesive. The four electrodes are arranged in a line on the mounting surface side, and are directly connected to opposing electrodes on the integrated circuit chip surface by solder. By this connection method, the thickness of the sensor can be the sum of the thickness of the integrated circuit chip and the height of the Z-axis GMI element. Since the thickness of the integrated circuit chip is usually 0.20 mm or less, when the height of the Z-axis GMI element of the present invention is 0.20 mm or less, the thickness of the GMI sensor can be 0.40 mm or less. .

The ultra-thin three-dimensional GMI sensor of the second embodiment is a combination of three GMI elements that detect magnetic fields in three directions of the X axis, the Y axis, and the Z axis and an integrated circuit chip as one package. . The Z-axis GMI element uses that of claim 1, the element plane is attached perpendicular to the integrated circuit chip surface, and both electrodes are joined by soldering. A desirable size is 0.20 mm or less × 0, 30 mm or less × 0, 20 mm or less. The X-axis and Y-axis GMI elements have the same wiring structure as the GMI element unit described in the first embodiment, and a desirable size is 0.20 mm or less × 0.30 mm or less × 0.20 mm or less. It is. The four electrodes are arranged so as to be symmetrical with respect to the X-axis and Y-axis of the element. When the element plane and the integrated circuit chip face each other and the electrodes are joined by soldering, the fixing and maintaining force is reduced. A balance can be secured.

Further, a conductive material post having the same thickness as the element is attached to the electrode that connects the integrated circuit chip and the external circuit board, and solder connection with the electrode of the external circuit board is performed. Finally, after molding with resin, the post surface is polished to ensure a smooth surface. As a result, the thickness of the three-dimensional sensor is the sum of the thickness of the integrated circuit chip and the height of the Z-axis GMI element, which is 0.40 mm or less. The element area is the same as the integrated circuit chip area, and is preferably 1.5 mm or less × 1.5 mm or less.

The analog electronic circuit for signal processing includes a pulse oscillator, a GMI element, a pulse-compatible buffer circuit, an electronic switch, a detection timing circuit, a sample hold circuit, and an amplifier. The coil voltage is input directly to the buffer circuit.

The buffer circuit is a circuit in which the input side and the output side have the same potential, the input side has a high impedance, and the output side can operate a low impedance circuit. Usually, the frequency band is 10 MHz or less, and the GMI sensor Does not follow the signals in the order of GHz. However, when a high-impedance sample-and-hold circuit is combined with a buffer circuit with a frequency band of 10 MHz or less and an output-side circuit, the output-side voltage is set to the input-side pulse when the pulsed energized electronic switch is turned on for an instant. It was found that it changes following the potential. This configuration is referred to as a pulse-compatible buffer circuit in the present invention.

The electronic circuit of the three-dimensional GMI sensor is connected to a digital circuit via a changeover switch in three signal processing circuits, and the digital circuit is composed of an AD converter, an arithmetic circuit for calculating a direction, and a communication circuit.
The three-dimensional GMI sensor of the present invention has a thickness of 0.4 mm or less, a cross section of 1,5 mm × 1.5 mm or less, and is ultra-compact and ultra-thin. The measurement range is ± 48G, and excellent performance can be realized.

The present invention will be described in detail based on the following examples with reference to the drawings.
[Example 1]
FIG. 1 shows a wiring structure of the Z-axis GMI sensor element 1 according to the first embodiment.
The structure of the unit magnetic field detection element is as follows. The size of the substrate is 0.3 mm in length, 0.2 mm in width, and 0.2 mm in height. The magnetic sensitive body is an amorphous magnetic wire 11 made of a CoFeSiB alloy and coated with glass with a diameter of 10 μm. A part of the magnetic wire 11 is embedded in a groove 12 formed on the substrate, a lower coil is disposed on the bottom surface of the groove 12, an upper coil is disposed on the upper portion of the wire, and both are fixed with a resin, on the plane of the substrate. It is a structure that is electrically joined. As for the coil, the outer diameter of the coil was 30 μm, the planar connection portion on the side surface of the coil was 5 μm, the convex portion of the coil was 20 μm, the line width was 2 μm, and the coil pitch was 4 μm. The size of the unit magnetic field detection element is as fine as a wire length of 200 μm, a coil length of 160 μm, a groove depth of 6 μm, and a coil convexity height of 7 μm.

In the wiring structure of the element 1, two wires 11 are installed along the groove 12, and a right-handed detection coil 13R is attached to one of them and a left-handed detection coil 13L is attached to the other. The two magnetic wires are connected in series so that the pulse current flowing through them is reversed. The current input from the integrated circuit chip connection input electrode 16 enters the wire connection terminal 14R on the right-handed coil side, flows through the wire, exits from the other wire connection terminal 15R, and then on the left-handed coil side connected in series. The wire connection terminal 15L enters, flows through the wire, exits from the other wire connection terminal 14L, and flows out to the integrated circuit chip connection ground electrode 17.

A pulse current flows in the positive direction through the right-handed coil 13R, and a pulse current flows in the negative direction through the left-handed coil 13L. The outputs of the two detection coils at this time are connected in series so that their output voltage polarities are opposite. That is, the coil output electrode 18 and the positive output terminal 181 of the right-hand coil are connected, the negative output terminal 182 of the right coil is connected to the positive output terminal 183 of the left coil, and finally the negative output terminal 184 of the left coil is connected to the coil ground. Connect to electrode 19.

If the output voltage proportional to the external magnetic field outputs a positive voltage to the right-hand coil, the left-hand coil outputs a negative voltage, but the output voltage has the same sign because the output voltage polarity is reversed and connected in series. Twice as much. On the other hand, the parasitic voltage generated by the circumferential magnetic field generated by pulse energization is a positive voltage when a positive voltage is output to the right-handed coil because both the direction of coil winding and the current direction are opposite to the left-handed coil. Since the polarities are reversed and they are connected in series, both have different signs and the output disappears. In other words, the polarity of the parasitic voltage derived from the right-handed coil and the polarity of the parasitic voltage derived from the left-handed coil are canceled by reverse connection. Eventually, only the component proportional to the magnetic field is output from the combination coil (basic unit element).

Furthermore, the positions of the coil voltage output electrode 18 and the ground electrode 19 must be kept away from the wire input terminal 16 and the ground terminal 17 to reduce the occurrence of parasitic voltage due to the wire voltage during energization. Therefore, the two coil coils are generated at the time of pulse energization by installing both coil terminals at positions in the vicinity of the wire-connecting terminal 25R on the right-handed coil side and the wire-connecting terminal 25L on the left-handed coil side. The parasitic voltage generated by the potential difference between the electrodes was reduced.

As for the arrangement of the four electrodes, the electrodes were arranged in alignment with the end face when standing and fixing on the integrated circuit chip surface. Solder is attached to the electrodes so that the solder can be directly soldered to the electrodes on the surface of the integrated circuit chip.

Although the coil resistance was 200Ω, the output voltage was measured by connecting to the pulse corresponding buffer circuit 4 shown in FIG. 4, and as a result, the output was able to obtain a predetermined output voltage.
For connection between this element and the integrated circuit chip, the four electrodes of the wire and the detection coil and the connection electrode on the integrated circuit chip side were directly connected by solder.

A pulse current having a conversion frequency of 1 GHz is supplied from the pulse oscillator 41 to the GMI element 1, and a coil voltage generated at that time is detected by the pulse corresponding buffer circuit 43. At this time, although the coil resistance is large, since the parasitic capacitance of the coil is extremely suppressed, only a very small current flows through the coil, and the voltage drop is as small as 5% of the coil output voltage. Both the input side circuit and the output side circuit of the buffer circuit have high impedance, and the concept of a normal buffer circuit, that is, the input side circuit is high impedance and the output side circuit is greatly different from low impedance. However, an instantaneous current flows through the coil by the pulse current of the wire, and the pulse corresponding buffer circuit 43 that functions as a buffer circuit only for the moment when the electronic switch 45 is opened and closed, that is, for the time interval of nanoseconds or less when the output side capacitor is charged. Thus, the coil voltage is sampled and held in the capacitor 46 without being attenuated, and is output through the amplifier 47.

Regarding the measurement range, the length of the magnetic wire was 0.2 mm and ± 48 G. Regarding the detection power, the coil pitch was reduced to 4 μm even when the wire length was shortened, the number of coil turns was increased to 80, and the detection capability was improved to 0.2 mG with a noise standard deviation σ. The element size was set to 0.20 mm × 0.30 mm × 0.20 mm by setting the distance between the wires to 40 μm.

[Example 2]
FIG. 2 is a plan view of the X-axis and Y-axis GMI elements according to the second embodiment, FIG. 3 is an assembly diagram of the three-dimensional GMI sensor, FIG. 4 is an analog circuit diagram for signal processing, and three-dimensional A circuit diagram of the GMI sensor is shown in FIG.
The Z-axis GMI element is the same as that of Example 1, and the structure of the GMI element unit, which is the magnetic field detection unit of the X-axis and Y-axis GMI elements, is the same as that for the Z-axis. The four electrodes 21, 25, 26, and 29 are arranged so as to be symmetric with respect to the X axis and the Y axis. The size of the Z-axis GMI element was 0.20 mm × 0.30 mm × 0.20 mm, and the size of the X-axis element and the Y-axis element was 0.20 mm × 0.20 mm × 0.20 mm.

The size of the integrated circuit chip is 1.2 mm × 1.2 mm × 0.20 mm, and there are eight X-axis and Y-axis electrodes 35 and Z-axis electrodes 34 for connecting to the GMI element on the upper surface. A total of 12 were attached. Further, twelve conductive posts 36 were attached symmetrically along the chip end.

After assembling the three GMI elements on the integrated circuit chip and performing resin molding 37, the upper surface of the post was polished to form a smooth surface, and solder was applied to the electrode portion formed by exposing the copper post.
The three-dimensional GMI sensor of Example 2 assembled by the above construction method had a cross section of 1.2 mm × 1.2 mm and a thickness of 0.40 mm.

In the signal processing of Example 2, the coil resistance of each of the three elements was 200Ω. However, as a result of measuring the output voltage by connecting to the pulse corresponding buffer circuit 43 shown in FIG. Voltage could be obtained. For subtle differences in the output characteristics of the X-axis element, the Y-axis element, and the Z-axis element, the gains are adjusted by the respective signal processing circuits 42 to obtain the same output characteristics, and then the X, Y, and Z are changed by the changeover switch 52. While switching in order, the signal is sent to the AD converter 53, the digitally converted data is subjected to a predetermined calculation in the arithmetic circuit 54, converted into an azimuth and angular velocity, and transferred to an external electronic circuit via the communication circuit 55 Decided to do.

The magnetic field detection performance of the sensor is as follows: even if the wire length is shortened, the coil pitch is reduced to 4 μm, the number of coil turns is increased to 80, the detection capability is improved, and the noise is 0.2 mG with a standard deviation σ. And improved. The measurement range was ± 48 G with the length of the magnetic wire being 0.2 mm.

The three-dimensional GMI sensor of Example 2 has a cross-section of 1.2 mm × 1.2 mm and a thickness of 0.40 mm, which is 1/7 by volume compared to the size of a commercially available GMI sensor of 2 × 2 × 1 mm. At the same time as realizing fleshing, the magnetic field detection performance improved from 2 mG to 0.5 mG with a standard deviation, and the measurement range was expanded from ± 12 G to ± 48 G, and the detection performance was greatly improved.

The Z-axis GMI element of the present invention and the three-dimensional GMI sensor assembled using the Z-axis GMI element realize a long and thin real-time three-dimensional azimuth meter using an electronic compass and a magnetic gyro function. The element of the present invention and a three-dimensional GMI sensor using the element meet the required characteristics of wearable computer motion input devices, ultra-miniaturization, ultra-thinness, noise reduction, improvement in azimuth accuracy, and real-time improvement. Therefore, it is expected to be widely used as a motion input device for mobile phones and wearable computers in the future.

1: Z-axis GMI element 11: magnetic wire, 12: substrate groove, 13R: right-handed coil, 13L: left-handed coil 14R: right-handed coil side wire input side terminal, 14L: left-handed coil side wire ground side terminal ,
15R: Right-handed coil side wire connection terminal, 15L: Left-handed coil side wire connection terminal,
16: ASIC connection input electrode, 17: ASIC connection ground electrode, 18: coil output electrode,
181: Positive output terminal of right-handed coil, 182: Negative output terminal of right-handed coil,
183: Positive output terminal of left-handed coil 184: Negative-side output terminal of left-handed coil 19: Coil ground electrode 2: GMI element 21 for X-axis and Y-axis 21: Input electrode for ASIC connection, 22: Right-handed coil Side wire input side terminal, 23: both wire connection terminals,
24: Left-hand coil side wire connection terminal, 25: ASIC connection ground electrode 26: Coil output electrode,
27: Positive output terminal of right-handed coil, 271: Connection portion 28 of both coils: Negative-side output terminal of left-handed coil 29: Coil ground electrode 3: Integrated circuit chip 31: Z-axis element, 32: X-axis element, 33 : Y-axis element, 34: Z-axis element electrode 35: X-axis, Y-axis electrode, 36: Conductive post, 37: Mold resin 4: Electronic circuit 41: Pulse oscillator, 42: Signal processing circuit, 43 : Pulse-compatible buffer circuit,
44: detection timing adjustment circuit, 45: electronic switch, 46: sample hold circuit 47: amplifier 5: electronic circuit of three-dimensional GMI sensor 51: digital circuit, 52: X, Y, Z axis changeover switch, 53: AD converter ,
54: arithmetic circuit, 55: communication circuit, 56: output terminal

Claims (2)

In the low-profile Z-axis GMI element required for an ultra-thin three-dimensional GMI sensor,
One or a plurality of GMI element units each including two magnetic wires having a length of 0.2 mm or less on the element plane and a right-handed coil and a left-handed coil each having a fine coil pitch, and two coil electrodes There are a total of four electrodes of two wire energizing electrodes, and the electrodes and terminals are connected in series so that the pulse current flows in the opposite direction through the two wire electrodes and the four wire terminals. It consists of a GMI element unit having a wiring structure in which two coil electrodes and four coil terminals are connected in series so that the detection coil output voltage is inverted.
Furthermore, the four electrodes are arranged in a line on the mounting surface side so that the electrodes of both the integrated circuit chip and the GMI element can be joined with solder when the element plane is mounted upright on the integrated circuit chip surface. Z-axis GMI element characterized in that the element height in the Z-axis direction is 0.20 mm or less and the number of coil turns is 30 or more. In an ultra-thin 3D GMI sensor that combines three GMI elements that detect magnetic fields in three directions of the X-axis, Y-axis, and Z-axis and an integrated circuit chip as one package,
The X-axis and Y-axis GMI element units have the same configuration as the Z-axis GMI element unit described in claim 1, and the four electrodes are two wire electrodes on one side of the wire on the element plane. However, two coil electrodes are arranged on the other side, the element plane and the integrated circuit chip surface are arranged in parallel, and both electrodes are joined by soldering,
In addition, the Z-axis GMI element according to claim 1 attaches the element plane perpendicular to the integrated circuit chip surface and joins both electrodes with solder.
Further, an ultra-thin 3 is characterized in that a conductive material post having a thickness equal to the thickness of the element is attached to an electrode connecting the integrated circuit chip and the external circuit board to perform solder connection with the electrode of the external circuit board. Dimensional GMI sensor.

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