JP4200358B2 - Current detection device with Hall element - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to a current detection device including a Hall element.
[0002]
[Prior art]
The Hall element generates a voltage that is directly proportional to the magnetic field applied thereto, that is, a Hall voltage. Therefore, when the Hall element is arranged along the current path, a magnetic field generated in proportion to the current flowing through the current path acts on the Hall element, and a voltage proportional to the current can be obtained from the Hall element.
[0003]
By the way, in order to improve the current detection sensitivity, the applicant of the present application is to provide an insulating film on the upper surface of the semiconductor substrate including the Hall element, and to provide a conductor layer as a path for the detected current on the insulating film. Proposed in PCT / JP99 / 05408. Thus, if the conductor layer is used as a path for the current to be detected on the semiconductor substrate, the current path can be brought close to the main operating region of the Hall element, and the detection sensitivity is improved.
However, it is difficult to pass a large current such as 100 A through the conductor layer on the semiconductor substrate.
[0004]
In order to solve this problem, the present applicant divides the detection current path formed of the printed conductor on the printed circuit board into the first and second current paths, and the second current path is formed in the conductor layer of the Hall element. Tried to connect. In this method, if the ratio of the resistance values of the first and second current paths is known in advance, the value of the detected current can be known by detecting the current of the second current path. Further, the change in the detected current can be known by detecting the current in the second current path.
However, in this method, the distance between the first current path and the second current path becomes relatively long, and a temperature difference is likely to occur between the two, so that the current in the first and second current paths is shunted. The ratio fluctuated and the current detection accuracy deteriorated.
[0005]
[Problems to be solved by the invention]
The current detection device using a hall element has a further problem that noise interferes with current detection.
[0006]
Therefore, an object of the present invention is to provide a current detection device using a Hall element that can suppress interference due to noise.
[0007]
[Means for Solving the Problems]
The present invention for solving the above problems and achieving the above object is an apparatus for detecting an electric current of an electric circuit, comprising one main surface and the other main surface opposite to the one main surface. A semiconductor substrate (23) having a hole element constituting semiconductor region (26, 27, 28) disposed on the one main surface side, and the other of the semiconductor substrates (23). A shield layer (17) covering the main surface, and a current path forming conductor (15) arranged on the one main surface side of the semiconductor substrate (23) for flowing a current to be detected. The present invention relates to a current detecting device including a hall element.
[0008]
Note that, as shown in claim 2, the current detection device for detecting the current of electrical circuits, a plate-shaped semiconductor having one main surface and the other main surface opposite to the main surface of the one A semiconductor substrate (23) in which a hole element constituting semiconductor region (26, 27, 28) is arranged on the one main surface side, and an insulating film covering one main surface of the semiconductor substrate (23) (3 2a ), a current path forming conductor (15) for flowing a detected current disposed on the one main surface side of the semiconductor substrate (23), and the current path forming conductor (15), the insulating film is formed by arranged and conductive material between the Cie - it and a shield layer (50) is desirable.
Further, as shown in claim 3, wherein the metal plate said the other main surface side of the semiconductor substrate (23) (2) is not to want to have been arranged.
[0009]
【The invention's effect】
According to the first aspect of the present invention, the external magnetic field acting on the other main surface side of the semiconductor substrate (23) can be shielded by the shield layer (17).
Also, a magnetic field based on the current conductor (15) for collecting passage formed e - can be favorably applied to Le element structure semiconductor regions (26, 27, 28). Further, the magnetic resistance of the path of the magnetic flux generated based on the current of the current path forming conductor (15) can be reduced by the action of the shield layer (17).
According to the invention of claim 2 , the external electric field noise or electromagnetic noise acting on one main surface side of the semiconductor substrate (23) is suppressed by the shield layer (50), and the noise resistance is improved. be able to. Further, since the shield layer (50) is disposed between the current path forming conductor (15) and one main surface of the semiconductor substrate (23), the voltage fluctuation of the current path forming conductor (15). Therefore, it is possible to suppress the voltage from being induced in the hole element .
According to a third aspect of the present invention, the hole element constituting semiconductor region (26, 27, 28) includes a shield layer (50) on one main surface side and a metal plate (50) on the other main surface side. sandwiched between 2), high sheet - Ru can be obtained field effect.
[0010]
[First Embodiment]
Next, a first embodiment of the present invention will be described with reference to FIGS.
The current detection device shown in FIGS. 1 and 2 is roughly divided into a hall element 1, a metal support plate 2, first and second current path terminals 3 and 4, first, second, third, The fourth, fifth and sixth external lead terminals 6, 7, 8, 9, 10, 11 and the first metal wire 12 as the first current path forming conductor, the second current path forming conductor The second and third metal wires 13 and 14 and the conductor layer 15, the insulating plate 16, the shield layer 17, and the resin sealing body 18 as an insulating enclosure are provided.
[0011]
As shown in FIGS. 3 and 8, the Hall element 1 is a quadrangle when viewed in a plane, that is, when viewed from a direction perpendicular to the main surface of the Hall element 1 and the main surface of the support plate 2. Second, third and fourth electrodes 19, 20, 21 and 22 are provided. When the Hall element 1 is used, a known control current supply circuit is connected to the first and second electrodes 19 and 20. A known amplifier is connected to the third and fourth electrodes 21 and 22. The first, second, third and fourth electrodes 19, 20, 21 and 22 are connected to the first, second, third and fourth semiconductor regions 24 and 25 of the semiconductor substrate 23 shown in FIGS. 7 and 8. , 26 and 27, respectively.
[0012]
The semiconductor substrate 23 is made of silicon having a rectangular shape when seen in a plan view. In addition to the n-type first, second, third, and fourth semiconductor regions 24, 25, 26, 27, the fifth, It has sixth, seventh and eighth semiconductor regions 28, 29, 30, 31. The fifth semiconductor region 28 has an n-type conductivity type, is formed in an island shape in the p-type eighth semiconductor region 31 occupying most of the semiconductor substrate 23, and is planarly formed as shown in FIG. It has a cruciform pattern. The first and second semiconductor regions 24 and 25 are n ⁺ type semiconductor regions having an impurity concentration higher than that of the fifth semiconductor region 28, and are separated from each other in the Y-axis direction as shown in FIG. Are formed in an island shape in the fifth semiconductor region 28. The first and second electrodes 19 and 20 are in ohmic contact with the first and second semiconductor regions 24 and 25. When a control current supply circuit is connected to the first and second electrodes 19 and 20, the fifth semiconductor has a direction from the first semiconductor region 24 toward the second semiconductor region 25 or the opposite direction. A known control current Ic flows in the region 28. Therefore, the first and second semiconductor regions 24 and 25 can also be called control current supply semiconductor regions.
[0013]
The third and fourth semiconductor regions 26 and 27 are n ⁺ type semiconductor regions having an impurity concentration higher than the n type impurity concentration of the fifth semiconductor region 28, and are in the Y-axis direction of the fifth semiconductor region 28. It is arranged near both ends of the central part. A part of the third and fourth semiconductor regions 26 and 27 is adjacent to the fifth semiconductor region 28, and the remaining part is adjacent to the sixth and seventh semiconductor regions 29 and 30 made of a p-type semiconductor. The third and fourth electrodes 21 and 22 are in ohmic contact with the third and fourth semiconductor regions 26 and 27 facing each other in the X-axis direction. The third and fourth semiconductor regions 26 and 27 can also be referred to as Hall voltage detecting semiconductor regions. The p-type sixth and seventh semiconductor regions 29, 30 limit the contact area of the n ⁺ -type third and fourth semiconductor regions 26, 27 with the fifth semiconductor region 28.
[0014]
When a control current Ic flows between the first and second semiconductor regions 24 and 25 and a magnetic field is applied so as to be orthogonal to the control current Ic, a well-known between the third and fourth semiconductor regions 26 and 27 is known. Hall voltage is obtained according to the principle of Hall effect. Therefore, the main operation region for generating the Hall voltage of the Hall element 1 is between the first and second semiconductor regions 24 and 25 in the fifth semiconductor region 28 and between the third and fourth semiconductor regions 26, 27 to each other. However, generally, the entire fifth semiconductor region 28 can be called the main operating region of the Hall element.
[0015]
A multilayer insulating film 32 made of, for example, silicon oxide is provided on one main surface of the semiconductor substrate 23, and a metal layer 33 made of, for example, aluminum is provided on the other main surface. However, the metal layer 33 can be omitted. The insulating film 32 is composed of first and second insulating films 32a and 32b. For example, a part of the first, second, third, and fourth electrodes 19, 20, 21, and 22 made of aluminum is disposed between the first and second insulating films 32 a and 32 b, and one of these electrodes is disposed. The end is in contact with the first, second, third, and fourth semiconductor regions 24, 25, 26, and 27 through the opening of the first insulating film 32a. The other ends of the first, second, third, and fourth electrodes 19, 20, 21, and 22 are led upward through the opening of the second insulating film 32b. The second current path forming conductor layer 15 is formed on the second insulating film 32b.
[0016]
As is apparent from FIG. 5, the support plate 2 is formed in a generally rectangular pattern when viewed from a direction perpendicular to the main surface, that is, when viewed in plan, and has a slightly larger area than the Hall element 1. The support plate 2 is a metal plate made of a copper plate or the like having a nickel plating layer on the surface having a thickness of about 0.5 to 1.0 mm, and has a function of mechanically supporting the Hall element 1. It also has a function as a heat sink and also functions as an electrostatic shield. Fifth and sixth external lead terminals 10 and 11 are led out from a pair of opposing edges of the support plate 2. The external lead terminals 10 and 11 are used for connection to the ground. The first and second current path terminals 3, 4 are arranged along one edge of the support plate 2. The first to fourth external lead terminals 6 to 9 for connecting the Hall element to the outside are slightly separated from the support plate 2. The support plate 2, the first and second current path terminals 3 and 4, and the first to sixth external lead terminals 6 to 11 are covered with a resin sealing body 18 indicated by a broken line in FIG. Connected to
[0017]
The support plate 2, the first and second current path terminals 3 and 4, and the first to sixth external lead terminals 6 to 11 for the Hall element are formed based on the lead frame 40 shown in FIG. Are made of metal plates of the same material and the same thickness. The lead frame 40 in FIG. 6 is used for connecting the first terminals 41, 6, 8, 10 on the left side and the terminals 4, 7, 9, 11 on the right side to each other. It has the 2nd strip | belt-shaped connection part 42 and the 3rd strip | belt-shaped connection part 43 for connecting the 1st and 2nd strip | belt-shaped connection parts 41 and 42. As shown in FIG. FIG. 6 shows a lead frame 40 including one hall element terminal 3, 4, 6-11, but in reality, one lead frame 40 has a plurality of terminals for a plurality of hall elements. Is provided. The first and second current path terminals 3 and 4 and the first to sixth external lead terminals 6 to 11 are cut at the position of the chain line in FIG. 6 after the resin sealing body 18 is formed.
[0018]
The insulating plate 16 is a rectangular ceramic plate, for example, whose plane shape is slightly larger than that of the Hall element 1. In addition to the function of insulating the Hall element 1 from the support plate 2, the magnetic layer 17 and the Hall element 1 are mechanically connected. It has a supporting function. The shield layer 17 formed on the upper surface of the insulating plate 16 so as to have a plane pattern substantially the same as that of the Hall element is made of a magnetic material having conductivity such as iron, nickel, cobalt, etc., and functions to shield an external electric field and a magnetic field. Have The shield layer 17 is connected to the external lead terminal 10 by a wire 17a. In addition to the magnetic shield effect, the shield layer 17 also has a function of reducing the magnetic resistance of the path of the magnetic flux generated based on the current of the conductor layer 15, that is, a magnetic flux collecting function. Note that a laminated body of the conductor layer and the magnetic layer can be used as the shield layer 17. The shield layer 17 can also be a nonmagnetic conductor such as Cu. The shield layer 17 can be an insulating magnetic layer such as ferrite.
[0019]
The insulating plate 16 provided with the shield layer 17 is fixed to the main surface of the support plate 2 by an insulating adhesive layer 34 as shown in FIGS. The metal layer 33 on the lower surface of the Hall element 1 is fixed to the shield layer 17 by a conductive bonding material layer 35 such as solder.
[0020]
The first, second, third and fourth electrodes 19, 20, 21 and 22 made of, for example, aluminum of the Hall element 1 are the first, second, third and fourth external leads as shown in FIG. The terminals 6, 7, 8, 9 are connected by metal wires 36, 37, 38, 39.
[0021]
The first metal wire 12 connected between the first and second current path terminals 3 and 4 is an aluminum wire for forming the first current passage, and the detected current Is is the first. And the first current Is1 when the current is divided into the second currents Is1 and Is2.
[0022]
A direction in which the conductor layer 15 made of aluminum, for example, is perpendicular to the main surface of the semiconductor substrate 23 in order to give the Hall element 1 a magnetic flux based on the current Is2 of the second current path connected in parallel to the first current path. The fifth semiconductor region 28 as a main operation region of the Hall element 1 is arranged inside the conductor layer 15. One end of the conductor layer 15 and the first current path terminal 3 are connected by a second metal wire 13 made of aluminum. The other end of the conductor layer 15 and the second current path terminal 4 are connected by a third metal wire 14 made of aluminum. The resistance value from one end to the other end of the first metal wire 12 is R1, and the resistance value from one end to the other end of the series circuit of the second metal wire 13, the conductor layer 15, and the third metal wire 14 is R2. Assuming that the resistances of the first and second current path terminals 3 and 4 are negligibly small, the currents Is1 and Is2 of the first and second current paths have the values shown in the following equations.
Is1 = Is {R2 / (R1 + R2)}
Is2 = Is {R1 / (R1 + R2)}
[0023]
When the current Is shown in FIG. 1 is used to detect or measure the current Is, the first and second current path terminals 3 and 4 are connected in series to the electric circuit, and the first and second external lead terminals 6 are connected. 7, a known control current supply circuit is connected, a control current Ic is passed between the first and second semiconductor regions 24, 25, and a known amplifier is connected to the third and fourth external lead terminals 8, 9. To do. As a result, a current Is1 comprising a part of the detected current Is is shunted to the conductor layer 15, and a magnetic field H having a direction indicated by a broken line in FIG. 8 is generated according to the right-handed ampere law. Since the direction of the magnetic field H is perpendicular to the direction of the control current Ic of the fifth semiconductor region 28, a hole is formed between the third and fourth semiconductor regions 26, 27, that is, between the third and fourth electrodes 8, 9. Voltage is generated. Since the Hall voltage is proportional to the magnetic field H and the magnetic field H is proportional to the detected current Is, the detected current Is can be detected by the Hall voltage.
[0024]
The current detection device of this embodiment has the following advantages.
(1) The detected current Is is divided into first and second currents Is1 and Is2, and one of these currents Is2 is detected. Therefore, the conductor layer 15 on the semiconductor substrate 23 has a relatively large value such as 100A. The current to be detected Is can be detected by flowing a small current of about 10 A, for example, without flowing a current. By setting the ratio of R1 and R2 to 1: 9, Is2 becomes 10A when Is is 100A.
(2) The first metal wire 12 as the first current path forming conductor and the second and third metal wires 13 and 14 and the conductor layer 15 as the second current path forming conductor are the same resin seal. Since the structure is covered with the stop 18, the temperature difference between the two can be reduced, the change in the ratio between the first and second currents Is 1 and Is 2 due to the temperature change is reduced, and highly accurate current detection is possible. It becomes possible.
(3) Since the first, second, and third metal wires 12, 13, and 14 are made of the same material, the resistance change rate due to temperature is also the same, the accuracy of the shunt ratio is increased, and highly accurate current detection can be performed. .
(4) Since the conductor layer 15 as a current path is provided on the insulating film 32 on the surface of the semiconductor substrate 23 on which the Hall element 1 is formed, and this conductor layer 15 is disposed adjacent to the Hall element 1, the current path is The Hall element 1 can be arranged close to the hall element 1, and the detection sensitivity of the current Is can be improved.
(5) Since the conductor layer 15 as a current path is disposed so as to surround about 95% of 3/4 or more of the entire circumference of the Hall element 1, the fifth semiconductor region 28 having a substantially rectangular shape in plan view is formed. Magnetic fields, that is, lines of magnetic force H can be applied to the fifth semiconductor region 28 from all directions of the four sides, and the detection sensitivity of the current Is1 can be improved.
(6) The Hall element 1, the support plate 2, the first and second current path terminals 3 and 4, the external lead terminals 6 to 11 and the wires 12 to 14 and 36 to 39 are covered with the resin sealing body 18. Therefore, these integration and protection can be achieved satisfactorily.
(7) Since the insulating plate 16 is provided, electrical separation between the Hall element 1 and the support plate 2 can be achieved satisfactorily.
(8) Since the shield layer 17 is provided, external noise based on magnetism and electric field can be removed.
(9) Since the support plate 2, the first and second current path terminals 3, 4, and the first to sixth external lead terminals 6-11 can be formed based on the lead frame 40, the current detection device Can be easily manufactured, and this cost can be reduced.
[0025]
[Second Embodiment]
Next, the current detection device of the second embodiment will be described with reference to FIG. However, in FIG. 9, parts that are substantially the same as those in FIG. Moreover, in description of 2nd Embodiment, FIGS. 1-7 is referred for the part which is common in 1st Example.
[0026]
The current detection device of the second embodiment omits the insulating plate 16, the shield layer 17, the metal layer 33, the insulating adhesive layer 34, and the conductive bonding layer 35 from the current detection device of the first embodiment of FIG. The support plate 2 is fixed to the lower surface of the semiconductor substrate 23 made of GaAs by the conductive bonding layer 35a made of Ag paste, and the shield layer 50, the current collector (magnet collector) 51, the third and third layers are formed on the upper surface side of the semiconductor substrate 23. Four insulating films 32c and 32d are added, and the others are configured in the same manner as in the first embodiment.
[0027]
The shield layer 50 made of a conductive material made of a molybdenum (Mo) layer having a thickness of about 0.1 μm is formed on the second insulating film 32b by, for example, vapor deposition, sputtering or plating. The shield layer 50 is disposed so as to cover at least the fifth semiconductor region 28 in a plan view, and is electrically connected to the fourth electrode 22 connected to the ground. The third insulating film 32 c is formed by vapor deposition or sputtering, and is disposed so as to cover the shield layer 50. The conductor layer 15 for forming the second current path is made of a gold (Au) layer having a thickness of about 5 to 13 μm, and is formed on the third insulating film 32c by plating, vapor deposition or sputtering. A magnetic current collector 51 made of a plate-like magnetic body (for example, ferrite, Fe, Ni, etc.) having a higher magnetic permeability than air is disposed on the fourth insulating film 32 d formed on the conductor layer 15. The magnetic current collector 51 is disposed so as to cover at least the fifth semiconductor region 28 in plan view, and is fixed on the conductor layer 15 by a fourth insulating film 32d made of an insulating resin adhesive. Instead of using the magnetic collector 51 as a plate-like magnetic body, a magnetic film may be formed on the fourth insulating film 32d by vapor deposition, coating, or the like, and this may be used as the magnetic collector.
[0028]
The current detection device of the second embodiment has the following advantages in addition to the same advantages as the above (1) to (6) and (9) of the first embodiment.
(1) Since the surface side of the main operating region including the fifth semiconductor region 28 of the Hall element is covered with the shield layer 50, a voltage is induced in the Hall element based on the voltage fluctuation of the conductor layer 15, and the first The phenomenon in which the voltage between the third and fourth electrodes 21 and 22 changes, that is, inductive noise, and external electric field noise or electromagnetic noise can be absorbed or suppressed by the shield layer 50, and the fifth semiconductor region of the Hall element The noise resistance of the main operation region including 28 can be improved.
(2) Since the support plate 2 and the conductive bonding layer 35a act as a shield layer for inductive noise on the lower side of the Hall element, this and the upper shield layer 41 sandwich the main operating region of the Hall element, A high shielding effect can be obtained.
(4) Since the magnetic current collector 51 is provided, the magnetic flux generated based on the current of the conductive layer 15 can be favorably guided to the fifth semiconductor region 28, and the current detection sensitivity can be increased.
[0029]
[Modification]
The present invention is not limited to the above-described embodiments, and for example, the following modifications are possible.
(1) The semiconductor substrate 23 can be formed of another semiconductor such as a group 3-5 compound semiconductor other than silicon or GaAs. In the case of a Group 3-5 compound semiconductor, since it is easily affected by an external magnetic field and induction noise, the value of the shield layers 17 and 50 becomes higher.
(2) Also in the current detection device having the structure of the first embodiment, a magnetic substance, that is, a magnetic current collector, can be disposed on the insulating film 32 of the Hall element 1 to increase detection sensitivity.
(3) An amplifier for amplifying the output voltage (Hall voltage) of the Hall element 1 can be formed in the semiconductor substrate 23.
(4) A plurality of Hall elements can be formed on the semiconductor substrate 23, current can be detected by a combination of the plurality of Hall elements, and this detection sensitivity can be increased.
[Brief description of the drawings]
FIG. 1 is a plan view showing a current detecting device according to a first embodiment of the present invention without a resin sealing body.
2 is a cross-sectional view showing the current detection device of FIG. 1 at a portion corresponding to line AA. FIG.
FIG. 3 is a plan view showing the Hall element of FIG. 1;
4 is a plan view showing an insulating plate having the shield layer of FIG. 1. FIG.
FIG. 5 is a plan view showing the support plate, first and second current path terminals, and first to sixth external lead terminals of FIG. 1;
6 is a plan view showing a part of a lead frame for the current detection device of FIG. 1; FIG.
7 is an enlarged plan view showing a semiconductor substrate of the Hall element shown in FIG. 1. FIG.
8 is an enlarged cross-sectional view showing a part of the Hall element of FIG. 1 along the line BB of FIG. 1;
FIG. 9 is a cross-sectional view showing a current detection device of a second embodiment, similar to FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hall element 2 Support plate 3, 4 1st and 2nd terminal 6 for current paths, 7, 8, 9, 10, 11 External lead terminals 12-14 Wire 15 Conductor layer

Claims (3)

A device for detecting the current of an electric circuit,
It consists of a plate-like semiconductor having one main surface and the other main surface opposite to the one main surface, and the hole element constituting semiconductor regions (26, 27, 28) are arranged on the one main surface side. A semiconductor substrate (23),
A shield layer (17) covering the other main surface of the semiconductor substrate (23);
And a current path forming conductor (15) for flowing a current to be detected arranged on the one main surface side of the semiconductor substrate (23). Detection device. A device for detecting the current of an electric circuit,
It consists of a plate-like semiconductor having one main surface and the other main surface opposite to the one main surface, and the hole element constituting semiconductor regions (26, 27, 28) are arranged on the one main surface side. A semiconductor substrate (23),
An insulating film ( 32a ) covering one main surface of the semiconductor substrate (23);
A current path forming conductor (15) for flowing a current to be detected disposed on the one main surface side of the semiconductor substrate (23) ;
The current path forming conductor (15) and the insulating film are formed by arranged and conductive material between the Cie - field layer (50),
A current detecting device including a hall element. 3. A current detecting device having a hall element according to claim 2 , wherein a metal plate (2) is arranged on the other main surface side of the semiconductor substrate (23).

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