JP3545074B2 - Magnetic detecting element and magnetic detecting module integrated on semiconductor substrate - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a magnetic detection element and a magnetic detection module using a soft magnetic core integrated on a semiconductor substrate.
[0002]
[Prior art]
A magnetic sensor using a soft magnetic material and a coil has been used as an extremely sensitive magnetic sensor for a long time. Such a magnetic sensor is manufactured by manually winding a coil around a relatively large rod-shaped core or a core obtained by winding a soft magnetic ribbon (thin ribbon) in a ring shape. In addition, an electronic circuit is required to obtain a voltage proportional to the measurement magnetic field.
[0003]
A method of realizing such a magnetic sensor element of a magnetic sensor with a thin film soft magnetic core and a planar thin film coil has also been devised.
[0004]
On the other hand, magnetic sensors using semiconductors are widely used because they are small and easy to mass-produce. Further, there has been proposed a method of forming an air-core coil on the same substrate as a semiconductor magnetic sensor and performing negative feedback by magnetic flux.
[0005]
[Problems to be solved by the invention]
The conventional magnetic sensor, in which a manually wound coil is wound around a large rod-shaped core or a ring-shaped core made of a soft magnetic ribbon, and the electronic circuit is composed of individual components, the magnetic detection unit and the entire device become large, and the production cost is high. Become.
[0006]
Further, in a conventional magnetic detecting element using a thin-film soft magnetic core and a planar thin-film coil, a large induced waveform due to a change in magnetic flux generated by the exciting coil appears in the detecting coil regardless of the presence or absence of the measurement magnetic field. This makes it difficult to amplify the waveform or extract a component proportional to the measured magnetic field from the change in the waveform. For example, high-sensitivity detection is difficult due to problems such as saturation of the waveform and a large offset.
[0007]
In a conventional magnetic sensor (without using a semiconductor substrate), there is a method for canceling an induced waveform when there is no measurement magnetic field.
[0008]
The conventional semiconductor magnetic sensor has low sensitivity and low resolution, and its use is limited. Further, even when the semiconductor magnetic sensor and the air-core coil are formed on the same substrate and negative feedback is performed, no remarkable improvement in sensitivity or resolution is found.
[0009]
The present invention eliminates the above-mentioned problems, and provides a magnetic detection element and a magnetic detection module integrated on a semiconductor substrate capable of performing high-sensitivity, accurate magnetic detection and miniaturization. The purpose is to.
[0010]
[Means for Solving the Problems]
The present invention, in order to achieve the above object,
(1) In a magnetic sensing element integrated on a semiconductor substrate, a soft magnetic film core formed on the semiconductor substrate, an exciting coil formed of a metal film for exciting the soft magnetic film core in an alternating current; And a magnetic flux change detection coil formed by a metal film.And two soft magnetic film cores are arranged side by side, and the soft magnetic film core is provided with an excitation coil n-turn (n is a positive integer) and a magnetic flux change detection coil m-turn (m is a positive integer) alternately. It has a repeatedly wound structure and cancels the induced waveform by the exciting coil when the detected magnetic field is zero.It is like that.
[0011]
(2A) a magnetic sensing element integrated on a semiconductor substrate, a soft magnetic film core formed on the semiconductor substrate, an exciting coil formed by a metal film for exciting the soft magnetic film core in an alternating current; And a magnetic flux change detection coil formed byAnd the excitation coil and the magnetic flux change detection coil are stacked as two planar coils, and the soft magnetic film core is stacked thereon.It is like that.
[0012]
(3A) a magnetic detection module using a magnetic material integrated on a semiconductor substrate, wherein the soft magnetic layer is formed on the semiconductor substrate;filmCore and this soft magnetismfilmIt has an excitation coil formed of a metal film for exciting the core in an alternating current and a magnetic flux change detection coil formed of the metal film.And two soft magnetic film cores are arranged side by side, and the soft magnetic film core alternately has an excitation coil n-turn (n is a positive integer) and a magnetic flux change detection coil m-turn (m is a positive integer). Has a structure wound repeatedly to cancel the induced waveform by the excitation coil when the detected magnetic field is zero.Things.
[0013]
(4) In a magnetic detection module using a magnetic material integrated on a semiconductor substrate, a soft magnetic layer formed on the semiconductor substratefilmCore and this soft magnetismfilmIt has an excitation coil formed of a metal film for exciting the core in an alternating current and a magnetic flux change detection coil formed of the metal film.And the excitation coil and the magnetic flux change detection coil are stacked as two plane coils, and the soft magnetic film core is stacked thereon.A magnetic detection element, an excitation coil driving integrated circuit connected to the excitation coil and integrated on the semiconductor substrate, and a magnetic detection signal connected to the magnetic flux change detection coil and integrated on the semiconductor substrate And a processing integrated circuit.
[0014]
(5) Above(3) or(4) In the magnetic detection module described in (4), the excitation coil driving integrated circuit includes a pulse oscillator, a frequency dividing circuit, and a driving circuit.
[0015]
(6) Above(3) or(4) The magnetic detection module according to (4), wherein the integrated circuit for processing magnetic detection signals includes a control signal generation circuit, a high-frequency amplifier, a cross-coupling switch, and a low-pass filter.
[0016]
(7) In a magnetic detection module using a magnetic material integrated on a semiconductor substrate, a semiconductor magnetic detection element formed on the semiconductor substrate, and a pair of soft magnetic cores arranged so as to sandwich the semiconductor magnetic detection element are provided. And an excitation coil formed of a metal film wound around the soft magnetic core.
[0017]
(8) In the magnetic detection module according to (7), the semiconductor magnetic detection element is a Hall element.
[0018]
(9) In the magnetic detection module according to (7), the semiconductor magnetic detection element is a split drain type magnetic transistor.
[0019]
(10) In a magnetic detection module using a magnetic material integrated on a semiconductor substrate, a divided drain type magnetic transistor formed at the center of the semiconductor substrate, and formed at the bottom of the groove and connected to the magnetic transistor A wiring layer, a lower wiring of a coil formed below the groove, a soft magnetic core formed above the lower wiring of the coil, and a lower wiring of the coil disposed above the soft magnetic core. An upper layer wiring of a coil to be connected is provided.
[0020]
[Action]
According to the present invention, as described above,
(1) In a magnetic sensing element integrated on a semiconductor substrate, a soft magnetic film core formed on the semiconductor substrate, an exciting coil formed of a metal film for exciting the soft magnetic film core in an alternating current; Since the magnetic flux change detection coil formed by the metal film is formed, the sensitivity is high, the weak magnetism can be detected accurately, and the magnetism integrated on the ultra-small semiconductor substrate. A detection element can be obtained.
[0021]
(2) In particular, it is possible to provide a magnetic sensor capable of laminating a soft magnetic film core, an exciting coil, and a magnetic flux change detecting coil on a monolithic semiconductor substrate by using a thin film technique.
[0022]
(3) Since the excitation coil and the detection coil are alternately wound one turn at a time on the semiconductor substrate, and two soft magnetic film cores are used to cancel the induced waveform when there is no external magnetic field, the winding structure is used. It is possible to obtain a magnetic detecting element which is ultra-small, has high sensitivity, and can detect a very weak magnetic field.
[0023]
(4) In a magnetic detection module using a magnetic material integrated on a semiconductor substrate, the magnetic detection element and an electronic circuit necessary for the magnetic detection element are integrated as an integrated circuit, so that the entire magnetic detection module is extremely small. Thus, it is possible to obtain a magnetic detection module that is ultra-small, highly sensitive, inexpensive, and excellent in mass production.
[0024]
(5) In particular, using a thin film technology on a monolithic semiconductor substrate, a soft magnetic film core, an exciting coil, a magnetic flux change detecting coil, and an electronic circuit required for the magnetic detecting element can be integrated as an integrated circuit as a magnetic. A detection module can be provided.
[0025]
【Example】
An embodiment of the present invention will be described with reference to the drawings.
[0026]
FIG. 1 is a schematic configuration diagram of a magnetic sensing element according to a first embodiment of the present invention, FIG. 2 is a timing chart showing the operation of the magnetic sensing element, and FIG. 2A is a waveform of a magnetic field in a soft magnetic film core 2a. FIG. 2B is a waveform diagram of a magnetic field in the soft magnetic film core 2b, FIG. 2C is a waveform diagram of a magnetic flux density in the soft magnetic film core 2a, and FIG. 2D is a magnetic flux in the soft magnetic film core 2b. FIG. 2E shows a voltage waveform induced in the detection coil 3a.₁, V_TwoFIG. 2F shows the voltage V induced in the detection coil 3a.₁+ V_TwoFIG.
[0027]
As shown in these figures, a structure in which two coils, that is, a detection coil (AA ′) 3a and an excitation coil (BB ′) 3b are wound around two soft magnetic film cores 2a and 2b. , On the semiconductor substrate 1. In the case where only a magnetic detection element is realized without integrating an integrated circuit, a glass substrate or the like can be used. When the exciting coil 3b is wound as shown in the figure, the magnetic field in the cores caused by the exciting AC current is reversed between the two cores. On the other hand, the detection coil 3a is wound over two cores. In this case, the induced voltage in the detection coil 3a generated due to electromagnetic induction due to the exciting AC current is such that the magnetic fields in the two cores are opposite. So they are canceled. External magnetic field H from core axis direction_mIs applied to the two cores in the same direction, the excitation magnetic field is changed to H_eThen, the magnetic fields in the two cores are H_m+ H_e, H_m-H_eIt becomes. At this time, as shown in FIG. 2, a voltage is induced in the detection coil 3a. By obtaining the magnitude, the external magnetic field H_mYou can know the size of the.
[0028]
In particular, in a magnetic detecting element using the semiconductor (silicon) substrate 1, it is important that the exciting coil 3b and the detecting coil 3a are alternately wound around the two soft magnetic film cores 2a and 2b by one turn.
[0029]
As described above, on the semiconductor substrate 1, the exciting coil 3b and the detecting coil 3a are alternately wound by one turn, and the external magnetic field H is formed by using the two soft magnetic film cores 2a and 2b._mWhen there is no winding structure, the winding structure cancels the induced waveform.
[0030]
Also, unlike the above configuration, detection can be performed by winding the excitation coil and the detection coil around one core, but in this case, a large induced voltage waveform is generated in the detection coil even without an external magnetic field. As a result, signal processing for the output of the detection coil such as amplification and filtering becomes complicated.
[0031]
Next, FIGS. 3 and 4 show an example in which the magnetic sensing element shown in FIG. 1 is formed on a semiconductor substrate.
[0032]
FIG. 3 is a schematic plan view of a magnetic sensor according to a first embodiment of the present invention, and FIG. 4 is a sectional view taken along line CC 'of FIG.
[0033]
As shown in these figures, an insulating film (silicon oxide film) 12 such as a silicon oxide film is formed on a semiconductor substrate (silicon substrate) 11, and two layers of metal wiring, ie, a lower layer of the coil, are formed thereon. By connecting the wiring 13 and the upper wiring 18 of the coil via the through hole 17, the exciting coil (BB ') 3b and the detecting coil (AA') having the same winding structure as shown in FIG. 3a is realized. The soft magnetic film core 15 is interposed between the upper wiring 18 of the coil and the lower wiring 13 of the coil via insulating films (polyimide, etc.) 14 and 16.
[0034]
Even in a conventional magnetic detecting element (without using a semiconductor substrate), an exciting coil and a detecting coil are wound around two cores to cancel the waveform induced by electromagnetic induction when there is no external magnetic field. ing. When a semiconductor substrate is used, it is important that the excitation coil and the detection coil are alternately wound by one turn. Otherwise, the soft magnetic film core has a large leakage magnetic flux, and the detection coil cannot sufficiently pick up a change in magnetic flux due to the exciting coil. One feature of the invention is a winding structure in which an exciting coil and a detecting coil are alternately wound on a semiconductor substrate by one turn, and two cores are used to cancel an induced magnetic field and an induced waveform when there is no external magnetic field. .
[0035]
Hereinafter, a method of manufacturing the magnetic sensing element according to the first embodiment will be described with reference to FIG.
[0036]
FIG. 5 is a sectional view showing the manufacturing process of the magnetic sensing element according to the first embodiment of the present invention. Here, a case where a semiconductor silicon substrate is used will be described.
[0037]
(1) First, as shown in FIG. 5A, an insulating film (silicon oxide film) 12 is formed on a silicon substrate 11 by thermal oxidation for insulation from the substrate.
[0038]
(2) Next, as shown in FIG. 5B, a metal material to be the lower wiring 13 of the coil is deposited and patterned by photolithography and etching in an IC process. Al or Cu is used as the metal material. There are various deposition methods such as sputtering and vapor deposition. When depositing Cu thickly, electroplating and electroless plating are effective.
[0039]
(3) Next, as shown in FIG. 5C, an insulating film (polyimide or the like) 14 for insulating is deposited. For this, a silicon oxide film formed by sputtering or CVD (Chemical Vapor Deposition), a hard-cured photoresist, polyimide, or the like can be used. At this time, flattening is performed so that the wiring pattern does not have irregularities on the underlayer of the magnetic film.
[0040]
(4) Next, as shown in FIG. 5D, a soft magnetic material is deposited and patterned to form a soft magnetic film core 15. As the deposition method, an electroplating method, a sputtering method, an evaporation method, or the like can be used. As the soft magnetic material, permalloy (an alloy of Ni and Fe), various amorphous magnetic alloys, and a multilayer soft magnetic film in which these and a nonmagnetic material are alternately stacked can be used.
[0041]
(5) Next, as shown in FIG. 5E, an insulating film (polyimide or the like) 16 for insulating is deposited.
[0042]
(6) Next, as shown in FIG. 5F, through holes 17 are formed by photolithography and etching.
[0043]
(7) Next, as shown in FIG. 5G, a metal material to be the upper wiring 18 of the coil is deposited and patterned. At this time, a large step is generated due to the magnetic film. Therefore, in photolithography, a thick film resist is used or a multilayer resist process is applied.
[0044]
Next, a second embodiment of the present invention will be described.
[0045]
FIG. 6 is a schematic configuration diagram of a magnetic sensor according to a second embodiment of the present invention.
[0046]
As shown in this figure, on a semiconductor substrate, detection coils 21a and 21b composed of two planar coils formed on the same plane, an excitation coil 22 composed of one planar coil disposed above the detection coils 21a and 21b, In this case, two soft magnetic film cores 23a and 23b formed on the same plane are arranged. That is, when the exciting coil 22 and the two soft magnetic film cores 23a and 23b are overlapped and excited as shown in FIG. 6, the two soft magnetic film cores 23a and 23b are excited in opposite directions. When the detection coils 21a and 21b are superposed on the detection coils 21a and 21b, voltage waveforms having opposite polarities are induced in the detection coils 21a and 21b below the soft magnetic film cores 23a and 23b by the AC exciting current. Therefore, if the detection coils 21a and 21b are wound as shown in FIG. 6, the induced voltage due to the exciting magnetic flux in the two soft magnetic film cores 23a and 23b is canceled, and the same operation and effect as in the first embodiment are expected. .
[0047]
FIG. 7 is a schematic plan view of a magnetic sensor according to a second embodiment of the present invention, and FIG. 8 is a sectional view taken along line DD 'of FIG.
[0048]
7 and 8, an insulating film 32 such as a silicon oxide film is formed on a semiconductor substrate 31, and a detection coil (lower wiring of the coil) 33 composed of two planar coils is formed thereon. An excitation coil (upper layer wiring of the coil) 35 is formed thereon via a (for example, polyimide) 34, and two soft magnetic film cores 37 formed on the same plane via an insulating film (for example, polyimide) 36. Is molded. 38 is a contact.
[0049]
Hereinafter, a method of manufacturing the magnetic sensor according to the second embodiment will be described with reference to FIG.
[0050]
FIG. 9 is a sectional view showing the manufacturing process of the magnetic sensing element according to the second embodiment of the present invention. Here, a case where a semiconductor silicon substrate is used will be described.
[0051]
(1) First, as shown in FIG. 9A, an insulating film (silicon oxide film) 32 is formed on a silicon substrate 31 by thermal oxidation for insulation from the substrate.
[0052]
(2) Next, as shown in FIG. 9B, a metal material to be the lower wiring 33 of the coil is deposited and patterned by photolithography and etching in an IC process. Al or Cu is used as the metal material. There are various deposition methods such as sputtering and vapor deposition. When depositing Cu thickly, electroplating and electroless plating are effective.
[0053]
(3) Next, as shown in FIG. 9C, an insulating film (polyimide or the like) 34 for insulating is deposited. For this, a silicon oxide film formed by sputtering or CVD (Chemical Vapor Deposition), a hard-cured photoresist, polyimide, or the like can be used. At this time, flattening is performed so that the wiring pattern does not have irregularities on the underlayer of the magnetic film.
[0054]
(4) Next, as shown in FIG. 9D, a metal material to be the upper wiring 35 of the coil is deposited, and is patterned by photolithography and etching in an IC process. Al or Cu is used as the metal material. There are various deposition methods such as sputtering and vapor deposition. When depositing Cu thickly, electroplating and electroless plating are effective.
[0055]
(5) Next, as shown in FIG. 9E, an insulating film (polyimide or the like) 36 for insulating is deposited. For this, a silicon oxide film formed by sputtering or CVD (Chemical Vapor Deposition), a hard-cured photoresist, polyimide, or the like can be used.
[0056]
(6) Next, as shown in FIG. 9 (f), a soft magnetic material is deposited and patterned to form a soft magnetic film core 37. As the deposition method, an electroplating method, a sputtering method, an evaporation method, or the like can be used. As the soft magnetic material, permalloy (an alloy of Ni and Fe), various amorphous magnetic alloys, and a multilayer soft magnetic film in which these and a nonmagnetic material are alternately stacked can be used.
[0057]
With this configuration, the manufacturing process is simpler than in the first embodiment, and the number of through holes is very small, so that the yield is improved.
[0058]
Further, when forming the upper layer wiring, since there is no large step, a normal photolithography process can be applied.
[0059]
In addition, since the soft magnetic film core can be formed last, no thermal stress is generated in the process of manufacturing the element in the soft magnetic film core, and the characteristics of the soft magnetic film core can be improved.
[0060]
Next, a third embodiment of the present invention will be described.
[0061]
FIG. 10 is a schematic configuration diagram of a magnetic detection module according to a third embodiment of the present invention.
[0062]
As shown in this figure, an excitation coil driving integrated circuit 42, a magnetic detection element 43 and a magnetic detection signal processing integrated circuit 44 are combined on a semiconductor (silicon) substrate 41 to constitute a magnetic detection module.
[0063]
Here, as the magnetic detecting element 43, the detecting element described in the first and second embodiments is used, and the magnetic detecting element and necessary electronic circuits are integrated on the same semiconductor substrate 41.
[0064]
FIG. 11 is a block diagram of an integrated circuit incorporated as a magnetic detection module according to a third embodiment of the present invention, and FIG. 12 is a timing chart showing circuit operation of the magnetic detection module.
[0065]
In FIG. 11, this magnetic detection module is roughly divided into an excitation coil driving integrated circuit 51, a magnetic detection element 55, and a magnetic detection signal processing integrated circuit 56.
[0066]
The excitation coil driving integrated circuit 51 includes a pulse oscillator 52, a frequency dividing circuit 53, and a driving circuit 54.
[0067]
The magnetic detection element 55 includes a core 55c, an excitation coil 55a, and a detection coil 55b.
[0068]
Further, the magnetic detection signal processing integrated circuit 56 includes a high-frequency amplifier 57, a cross-coupling switch circuit 58, a low-pass filter 59, and a phase adjustment and control signal generator 60.
[0069]
First, the voltage pulse P₁(4f₀), And this voltage pulse P₁(4f₀) Is first passed through a frequency dividing circuit (first stage) 53 to generate a pulse P having a frequency of 1/2 and a duty ratio of 50%._Two(2f₀). The frequency of this pulse (2f₀) Is a high frequency of about 1 MHz or more to obtain a sufficiently high sensitivity. Further, the frequency dividing circuit (second stage) 53 generates a pulse P having a frequency of 1/2_Three(F₀). In the drive circuit 54, the pulse P_Three(F₀) Is converted to a triangular wave, and the exciting coil 55a of the magnetic detection element 55 is turned into a triangular wave current P._FourDrive with At this time, if there is no external magnetic field, no voltage appears in the detection coil 55b of the magnetic detection element 55, and when an external magnetic field is applied, a waveform as shown in FIG. Here, when the direction of the magnetic field is the forward direction, if the waveform is as shown by the solid line, the waveform as shown by the broken line is obtained with respect to the magnetic field in the reverse direction. After this waveform is amplified by the high-frequency amplifier 57, it is passed through the cross-coupling switch circuit 58. Here, the polarity of the voltage is switched using two pulses as shown in FIG. 12A and FIG. ).
[0070]
FIG. 13 is an explanatory diagram of the operation of the cross-coupling switch circuit, showing the principle of switching the polarity of the voltage.
[0071]
In this figure, when the control signal φ is “1”, the switches are controlled so that they are connected straight, and the polarities of the input and output voltages are the same, but when φ is “0”, the connections are crossed. The switch is controlled, and the polarity of the voltage is inverted. Therefore, if control is performed at the timing as shown in FIG. 12, a waveform as shown in FIG. 12 (f) can be obtained. Thereafter, when this is passed through a low-pass filter 59, a DC component having the waveform shown in FIG. 12 (g) is obtained, but its magnitude is proportional to the magnitude of the external DC magnetic field. it can. In the case of the magnetic field of the reverse method, the waveform of FIG. 12 (g) is as shown by the broken line, and after passing through the low-pass filter, a voltage of the opposite polarity is obtained. That is, it is possible to perform directional detection.
[0072]
If the above cross-coupling switch circuit is realized by a MOS transistor circuit, a circuit as shown in FIG. 14 is obtained.
[0073]
Next, a fourth embodiment of the present invention will be described.
[0074]
FIG. 15 is a schematic configuration diagram of a magnetic detection module according to a fourth embodiment of the present invention.
[0075]
In this embodiment, a semiconductor magnetic sensor is used in place of the detection coil. More specifically, in FIG. 15 (a), a semiconductor magnetic detecting element 61 using a Hall element is arranged at the center, and this is configured by combining soft magnetic cores 62, 63 and exciting coils 64, 65. It is a detection module.
[0076]
Further, in FIG. 15B, a semiconductor magnetic detecting element 71 using a split drain type magnetic transistor is disposed at the center, and the magnetic detecting element 71 is configured by combining soft magnetic cores 72, 73 and exciting coils 74, 75. Module.
[0077]
It can be considered that these converge the magnetic flux by the soft magnetic core and increase the sensitivity of the semiconductor magnetic detection element. In order to obtain a sufficient effect, first, a sufficiently long core is used in consideration of the influence of the demagnetizing field. A semiconductor magnetic sensing element is arranged in the gap between the two cores, and the gap is made as narrow as possible. In addition, a coil is wound around the core, and the core is excited with an AC signal having a sufficiently large amplitude to saturate the magnetization of the core. The semiconductor magnetic detecting element detects a change in the magnetic flux density waveform of the core caused by the sum of the magnetic field due to the AC exciting current and the external magnetic field. The magnetic flux density waveform changes due to the external magnetic field, and by performing appropriate signal processing, a voltage proportional to the external magnetic field can be obtained.
[0078]
If such AC excitation is not used, the core is magnetized, the sensitivity is reduced, and the detection characteristics have hysteresis.
[0079]
FIG. 16 is a schematic plan view when a magnetic detection module according to a fourth embodiment of the present invention is realized on a semiconductor substrate, and FIG. 17 is a sectional view taken along line AA 'of FIG.
[0080]
Here, two split-drain magnetic transistors are used as the semiconductor magnetic detecting elements. In this method, a trapezoidal groove with a crystal axis anisotropic etching is formed using a single crystal silicon substrate, and two magnetic transistors are formed on the slope of the groove. Utilizing the slope of the groove, a lower metal wiring is formed, and a magnetic material is embedded in the groove. A coil is formed by forming an upper layer wiring thereon and spirally connecting the lower layer wiring via a through hole. In this way, a structure similar to that of FIG. 15B can be realized.
[0081]
16 and 17, reference numeral 81 denotes a p-type single crystal silicon substrate; 84, an n-type impurity layer serving as a channel formed in a deep portion; 85, a p-type impurity layer serving as an upper gate formed in a shallow portion; Represents the drain (n) of a split drain type magnetic transistor using an n-channel junction type field effect transistor.⁺) Diffusion layer 88 is a source (n) of a split drain type magnetic transistor using an n-channel junction type field effect transistor.⁺) A diffusion layer, 89 is a silicon oxide film, 90 is a lower wiring of the coil, 91 is an insulating film (polyimide or the like), 92 is a soft magnetic core made of a soft magnetic material embedded in a groove, and 93 is an insulating film (polyimide or the like). , 94 are contact holes, 95 is an upper layer wiring of the coil, 96 is a contact, and 97 is a metal electrode.
[0082]
FIG. 18 is a view showing the operation principle of the semiconductor magnetic sensor unit according to the fourth embodiment of the present invention. The operation principle of the semiconductor magnetic sensor unit will be described with reference to FIG. When a magnetic field is applied perpendicular to the surface of the surface, the electrons that are carriers are bent by the Lorentz force due to the magnetic field, causing a current difference between the two drains. The difference is proportional to the magnitude of the magnetic field. It is to take advantage of that.
[0083]
If these two magnetic transistors are arranged and connected at an angle as shown in FIG. 18, the magnetic field in the direction shown in FIG._a1, I_b1Increases, and conversely, I_a2, I_b2Decreases. Therefore, by simply connecting the two magnetic transistors as shown in FIG. 18, the sum of the current changes of the two magnetic transistors can be obtained. Also, each magnetic transistor has a maximum sensitivity in a direction perpendicular to the plane, but they are inclined with respect to the axis of the core. However, by calculating the sum of the two, the combined output has the maximum sensitivity in the axial direction of the core.
[0084]
FIG. 19 is a sectional view showing the manufacturing process of the magnetic detection module according to the fourth embodiment of the present invention. Here, a case where a semiconductor silicon substrate is used will be described.
[0085]
(1) First, as shown in FIG. 19A, a silicon oxide film is grown on a p-type single crystal silicon substrate 81 having a plane orientation of 100, and a silicon oxide film 82 is formed by photolithography.
[0086]
(2) Next, using the silicon oxide film 82 as a mask, trapezoidal grooves are formed by crystal axis anisotropic etching as shown in FIG. This is based on the fact that the etching rate in the 111 direction becomes extremely slower than that in the 100 direction when a special alkali-based etchant is used. As a result, an accurate trapezoidal three-dimensional structure in which the plane corresponding to the 111 plane is a slope is obtained. A split drain type magnetic transistor based on an n-channel junction field effect transistor is formed on the slope of the groove. First, using the patterned photoresist 83 as a mask, an n-type impurity is deeply introduced by ion implantation to form an n-type impurity layer 84 serving as a channel. Next, a p-type impurity is introduced shallowly to form a p-type impurity layer 85 serving as an upper gate.
[0087]
(3) Next, as shown in FIG. 19C, a silicon oxide film 86 is grown by thermal oxidation also serving as a heat treatment.
[0088]
(4) Next, as shown in FIG. 19D, a high concentration n-type impurity is introduced to remove the oxide film at the source and drain portions and to take an electrode at these portions. The drain (n) of a split drain type magnetic transistor using a field effect transistor⁺) The source (n) of the split drain type magnetic transistor using the diffusion layer 87 and the n-channel junction type field effect transistor⁺) A diffusion layer 88 is formed. This can be done by either thermal diffusion or ion implantation.
[0089]
(5) Next, as shown in FIG. 19 (e), after the silicon oxide film 89 is entirely grown again, a metal material to be the lower wiring 90 of the coil is deposited and patterned.
[0090]
(6) Next, as shown in FIG. 19 (f), after depositing an insulating film (polyimide or the like) 91 made of an insulating material, depositing a soft magnetic material in a form buried in the groove, and then patterning. Thus, a soft magnetic core 92 is formed.
[0091]
(7) Next, an insulating film (polyimide or the like) 93 is deposited again, a contact hole 94 is formed, and then an upper wiring 95 of the coil is deposited and patterned, and the upper wiring 95 of the coil and the lower wiring 90 of the coil are formed. Are connected by a contact 96 to complete the coil structure, and a metal electrode 97 to the source and drain of the magnetic transistor is formed.
[0092]
FIG. 20 shows the configuration of the magnetic detection module shown in FIG. The operation will be described with reference to the timing chart of FIG.
[0093]
A reference clock a output from the pulse oscillator 101 and shown in FIG. 21A is passed through a frequency dividing circuit 102 to generate a pulse b having a frequency of 1/2 and a duty ratio of 50% as shown in FIG. 21B. The coil driving circuit 103 converts the waveform into a triangular waveform c shown in FIG. 21C and drives the core with a large amplitude enough to sufficiently saturate the magnetization of the core. At this time, the magnetic flux density waveform in the core saturates when the amplitude of the magnetic field increases, and when this is detected by the magnetic transistor sandwiched between the gaps between the two cores, the magnetic transistor shows the magnetic flux density waveform in the core as the magnetic flux density waveform. A similar voltage waveform d shown in FIG. 21D is generated. When there is no external magnetic field, the waveform is symmetric. However, when an external DC magnetic field is superimposed, the waveform changes as shown by a broken line. When the output of the magnetic transistor is amplified by an AC (AC) amplifier 108 and the DC component is cut, the result is as shown in FIG. 21 (e). , As indicated by the broken line. Therefore, the difference between the heights of the trapezoids can be obtained by sampling the positive and negative peak values of the trapezoidal waveform, and calculating the sum of these. This value is proportional to the external magnetic field. Such an operation can be performed by the switched capacitor type subtractor 110 and the S / H (sample / hold) circuit 120. First, a pulse as shown in FIG. 21 (f) is generated, thereby sampling a negative peak value.₁Charge. Next, when the positive peak value is sampled by the pulse shown in FIG.₁Is charged, and a charge proportional to the difference between the positive and negative peak values is charged by the capacitor C._TwoIs forwarded to The resulting voltage (h) shown in FIG. 21 (h) is sampled and held by the S / H circuit 120, thereby obtaining a DC voltage as shown in FIG. 21 (i). Its magnitude is proportional to the external magnetic field.
[0094]
In FIG. 20, 105 is a DC power supply, 106 and 107 are resistors, and 109 is a control.signalGenerating circuit, 111, 112, 116 and 121 are switches,C ₁ , C _Two ,C_ThreeIs a capacitor113, 115, 122It is. In addition, 104 is a detection coil, 114,123Is a MOS type operational amplifier.
[0095]
Such an electronic circuit can be manufactured and integrated on the same silicon substrate together with the detection element as in the case of the third embodiment.
[0096]
It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.
[0097]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
[0098]
(1) In a magnetic sensing element integrated on a semiconductor substrate, a soft magnetic film core formed on the semiconductor substrate, an exciting coil formed by a metal film for exciting the soft magnetic film core in an alternating current; Since a magnetic flux change detection coil formed of a metal film is formed, a highly sensitive and accurate magnetic detection can be performed, and the magnetic detection element is integrated on a very small semiconductor substrate. Can be obtained.
[0099]
(2) In particular, it is possible to provide a magnetic sensor capable of laminating a soft magnetic film core, an exciting coil, and a magnetic flux change detecting coil on a monolithic semiconductor substrate by using a thin film technique.
[0100]
(3) Since the excitation coil and the detection coil are alternately wound one turn at a time on the semiconductor substrate, and two soft magnetic film cores are used to cancel the induced waveform when there is no external magnetic field, the winding structure is used. Thus, it is possible to obtain a magnetic detecting element which is ultra-small, has high sensitivity, and can detect an extremely weak magnetic field.
[0101]
(4) In a magnetic detection module using a magnetic substance integrated on a semiconductor substrate, the magnetic detection element and an electronic circuit necessary for the magnetic detection element are integrated as an integrated circuit, so that the entire magnetic detection module is ultra-small. Thus, it is possible to obtain a magnetic detection module that is ultra-compact, has high sensitivity, is inexpensive, and can be easily mass-produced.
[0102]
(5) In particular, using a thin film technology on a monolithic semiconductor substrate, a soft magnetic film core, an exciting coil, a magnetic flux change detecting coil, and an electronic circuit required for the magnetic detecting element can be integrated as an integrated circuit as a magnetic. A detection module can be provided.
[0103]
The magnetic detection element and the magnetic detection module obtained in this way are, for example, a navigation system based on geomagnetic detection, a geomagnetic fluctuation monitor (earthquake prediction), some biomagnetic measurements, metal material defect detection, indirect applications, It can be widely used as a magnetic encoder, a contactless potentiometer, a current sensor, a torque sensor, a displacement sensor, and the like.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a magnetic sensing element according to a first embodiment of the present invention.
FIG. 2 is a timing chart showing the operation of the magnetic sensor according to the first embodiment of the present invention.
FIG. 3 is a schematic plan view of a magnetic sensor according to a first embodiment of the present invention.
FIG. 4 is a sectional view taken along line CC ′ of FIG. 3;
FIG. 5 is a sectional view showing the manufacturing process of the magnetic sensing element according to the first embodiment of the present invention.
FIG. 6 is a schematic configuration diagram of a magnetic sensor according to a second embodiment of the present invention.
FIG. 7 is a schematic plan view of a magnetic sensor according to a second embodiment of the present invention.
FIG. 8 is a sectional view taken along line DD ′ of FIG. 7;
FIG. 9 is a cross-sectional view illustrating a manufacturing process of the magnetic sensing element according to the second embodiment of the present invention.
FIG. 10 is a schematic configuration diagram of a magnetic detection module according to a third embodiment of the present invention.
FIG. 11 is a block diagram of an integrated circuit incorporated as a magnetic detection module according to a third embodiment of the present invention.
FIG. 12 is a timing chart illustrating a circuit operation of the magnetic detection module according to the third embodiment of the present invention.
FIG. 13 is an explanatory diagram of an operation of the cross-coupling switch circuit of the magnetic detection module according to the third embodiment of the present invention.
FIG. 14 is a circuit diagram in which a cross-coupling switch circuit of a magnetic detection module according to a third embodiment of the present invention is realized by a MOS transistor circuit.
FIG. 15 is a schematic configuration diagram of a magnetic detection module showing a fourth embodiment of the present invention.
FIG. 16 is a schematic plan view when a magnetic detection module according to a fourth embodiment of the present invention is realized on a semiconductor substrate.
FIG. 17 is a sectional view taken along line AA ′ of FIG. 16;
FIG. 18 is a diagram illustrating the operation principle of a semiconductor magnetic sensor unit according to a fourth embodiment of the present invention.
FIG. 19 is a sectional view showing the manufacturing process of the magnetic sensor according to the fourth embodiment of the present invention.
FIG. 20 is a configuration diagram of a magnetic detection module showing a fourth embodiment of the present invention.
FIG. 21 is a timing chart of a magnetic detection module according to a fourth embodiment of the present invention.
[Explanation of symbols]
1,11,31,41 Semiconductor substrate (silicon substrate)
2a, 2b, 15, 23a, 23b, 37 Soft magnetic film core
3a, 21a, 21b, 55b, 104    Detection coil
3b, 22, 55a, 64, 65, 74, 75 Excitation coil
12,32 insulating film (silicon oxide film)
13,33,90 Lower layer wiring of coil
14, 16, 34, 36, 91, 93 Insulating film (polyimide etc.)
17 Through hole
18,35,95 Upper layer wiring of coil
38 contacts
42,51 Integrated circuit for driving excitation coil
43,55 Magnetic sensing element
44,56 Magnetic detection signal processing integrated circuit
52,101 pulse oscillator
53,102 frequency divider circuit
54,103 drive circuit
55c core
57 High frequency amplifier
58 Cross-coupled switch circuit
59 Low-pass filter
60 Phase adjustment and control signal generator
61,71 semiconductor magnetic sensing element
62, 63, 72, 73, 92 Soft magnetic core
81 p-type single crystal silicon substrate
82,86,89 Silicon oxide film
83 Photoresist
84 channel n-type impurity layer
85 P-type impurity layer serving as upper gate
87 The drain (n) of the split-drain magnetic transistor⁺) Diffusion layer
88 Source (n⁺) Diffusion layer
94 Contact hole
96 contacts
97 metal electrode
105 DC power supply
106,107 resistance
108 AC (AC) Amplifier
109 Control pulse generation circuit
110 Subtractor
111,112,116, 121 switch
113, 115, 122    Capacitor
114,124    MOS operational amplifier
120 S / H (sample / hold) circuit

Claims (10)

In the magnetic detecting element are integrated on a semiconductor substrate, a soft magnetic film core formed on a semi-conductor substrate, and the excitation coil formed by a metal film for AC-excited the soft magnetic film core, the metal film And two soft magnetic film cores are juxtaposed, and the soft magnetic film core has an exciting coil n-turn (n is a positive integer) and a magnetic flux change detecting coil. A magnetic detecting element having a structure in which m turns of a coil (m is a positive integer) are alternately and repeatedly wound, and a waveform induced by an exciting coil is canceled when a magnetic field to be detected is zero . In a magnetic sensing element integrated on a semiconductor substrate, a soft magnetic film core formed on the semiconductor substrate, an exciting coil formed of a metal film for exciting the soft magnetic film core in an alternating current, and a metal film A magnetic detection element having a structure in which a magnetic flux change detection coil to be formed is formed, and wherein the excitation coil and the magnetic flux change detection coil are stacked as two planar coils, and the soft magnetic film core is stacked thereon . In a magnetic detection module using a magnetic material integrated on a semiconductor substrate,
(A) said a soft magnetic film core formed on a semiconductor substrate, an excitation coil formed of a metal film for AC-excited soft magnetic film core, magnetic flux change detection formed by the metal film It has a coil, and the soft magnetic film core was 2 Konami設exciting coil n turns in the magnetically soft film core (n is a positive integer) and the magnetic flux change detecting coil m turn (m is a positive A magnetic sensing element having a structure in which an integer is alternately and repeatedly wound, and when the detected magnetic field is zero, the induced waveform by the exciting coil is canceled .
(B) an excitation coil driving integrated circuit connected to the excitation coil and integrated on the semiconductor substrate;
(C) a magnetic detection module comprising: a magnetic detection signal processing integrated circuit connected to the magnetic flux change detection coil and integrated on the semiconductor substrate. In a magnetic detection module using a magnetic material integrated on a semiconductor substrate,
(A) said a soft magnetic film core formed on a semiconductor substrate, an excitation coil formed of a metal film for AC-excited soft magnetic film core, magnetic flux change detection formed by the metal film a magnetic sensing element have a coil, and overlaid the excitation coil and the magnetic flux change detecting coil as two planar coils, to have a structure of repeating the soft magnetic film core thereon,
(B) an excitation coil driving integrated circuit connected to the excitation coil and integrated on the semiconductor substrate;
(C) a magnetic detection module comprising: a magnetic detection signal processing integrated circuit connected to the magnetic flux change detection coil and integrated on the semiconductor substrate. 5. The magnetic detection module according to claim 3 , wherein the excitation coil driving integrated circuit includes a pulse oscillator, a frequency dividing circuit, and a driving circuit. The magnetic detection module according to claim 3 , wherein the integrated circuit for processing a magnetic detection signal includes a control signal generation circuit, a high-frequency amplifier, a cross-coupled switch, and a low-pass filter. In a magnetic detection module using a magnetic material integrated on a semiconductor substrate,
(A) a semiconductor magnetic sensing element formed on a semiconductor substrate;
(B) a pair of soft magnetic cores arranged so as to sandwich the semiconductor magnetic sensing element;
(C) an excitation coil formed of a metal film wound around the soft magnetic core. The magnetic detection module according to claim 7, wherein the semiconductor magnetic detection element is a Hall element. The magnetic detection module according to claim 7, wherein the semiconductor magnetic detection element is a split drain type magnetic transistor. In a magnetic detection module using a magnetic material integrated on a semiconductor substrate,
(A) a split-drain magnetic transistor formed at the center of a semiconductor substrate;
(B) grooves formed on both sides of the magnetic transistor;
(C) a wiring layer formed at the bottom of the groove and connected to the magnetic transistor;
(D) lower-layer wiring of a coil formed below the groove;
(E) a soft magnetic core formed above the lower wiring of the coil;
(F) A magnetic detection module which is disposed above the soft magnetic core and includes an upper wiring of the coil connected to a lower wiring of the coil.

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