JP2007108011A - Magnetic sensor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic sensor which has a magnetic amplification structure for improving sensitivity, is small, has high sensitivity, and has favorable temperature characteristics and its manufacturing method. <P>SOLUTION: A semiconductor thin film 11 having a magnetosensitive section 11a is provided on a substrate 10. Metallic electrodes 12 are provided on both ends of the magnetosensitive section 11a. A first base layer 14 is provided through a protective layer 13 on the front side in the vicinity of the magnetosensitive section 11a. A first magnetic body 17 having a magnetic amplification function is provided on the first base layer 14. A second base layer 15 is provided on the substrate 10 and on the back of the magnetosensitive section 11a. A second magnetic body 18 having a magnetic amplification function, in conjunction with the first magnetic body 17, is provided on the second base layer 15. A simple manufacturing process performing only magnetic body plating can provide the magnetic amplification structure, thereby achieving the magnetic sensor which is small, has high sensitivity, and has favorable temperature characteristics. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic sensor such as a Hall element and a method for manufacturing the same, and more specifically, a small magnetic sensor having a magnetic amplifying structure that improves the sensitivity of a magnetic sensing part, a high-sensitivity magnetic sensor, and a method for manufacturing the same. About.

  Conventional magnetic sensors using the Hall effect are used in a wide range of fields such as azimuth sensors, position detection sensors, and current sensors that detect the direction of magnetic lines of force due to geomagnetism. In particular, recently, there has been a demand for a small and highly sensitive magnetic sensor, and as a magnetic sensor structure therefor, a magnetic sensor having a magnetic amplification structure that improves the sensitivity of the magnetic sensing portion has been proposed.

  FIG. 7 is a configuration diagram showing a Hall element as a conventional magnetic sensor. In this Hall element, a magnetic thin film 22 having a magnetically sensitive portion 22a patterned in a cross shape is provided on a magnetic body 21 made of a magnetic material having a high magnetic permeability such as ferrite, thereby providing a magnetic flux to the magnetically sensitive portion 22a. To improve the sensitivity (see, for example, FIG. 5 of Patent Document 1). Reference numeral 23 denotes a metal electrode.

  FIG. 8 is a block diagram showing another example of a conventional Hall element. By positioning magnetic materials such as ferrite above and below the magnetic sensitive part, the magnetic amplification function of the magnetic sensitive part is enhanced and the sensitivity is greatly improved. It is made to let you. The Hall element is provided with a semiconductor thin film 32 having a magnetic sensing portion 32a patterned in a cross shape on a first magnetic body 31, and further, a second functioning as a magnetic material for magnetic amplification on the magnetic sensing portion 32a. The magnetic body 34 is provided (see, for example, FIG. 6 of Patent Document 1). Reference numeral 33 denotes a metal electrode.

  Further, similarly to the Hall element shown in FIG. 8, a configuration in which the magnetic sensing portion is sandwiched between the first magnetic body and the second magnetic body is disclosed in, for example, Patent Document 2. . In the magnetic sensor described in Patent Document 2, a magnetic sensing part for detecting an external magnetic field is provided on a magnetic substrate, and the magnetic sensing part is sandwiched between a ferrite chip, which is a magnetic material, and a ferrite substrate. The magnetic parts are arranged on the magnetic substrate at a predetermined interval via the ferrite substrate, and are configured so that the magnetism converged on the magnetic substrate can penetrate the magnetic sensitive part. In other words, it has a structure in which a first magnetic body having a main plane and a second magnetic body that is a magnetic converging chip are arranged on the opposite side of the magnetic sensing portion. A method for manufacturing a magnetic sensor is also disclosed.

  Further, for example, Patent Document 3 discloses that a magnetically sensitive portion made of a magnetic thin film constituting a magnetic sensor used as a current sensor is formed of a CoFeN or NiFe plating film.

JP-A-11-261130 JP 2004-61380 A JP 2002-296304 A

  However, if a magnetic material is provided only on the back surface side of the magnetic sensor as shown in FIG. 7, that is, only on one surface, the wire bonding space need not be considered. There is a problem that the sensitivity is not so high and the sensitivity is improved only about 1.3 times at the maximum. In addition, since the sensitivity is extremely lowered when the distance between the magnetic sensitive part and the magnetic body is increased, it is necessary to cut the substrate material having the magnetic sensitive part very thinly. For this purpose, it is necessary to devise a method such as transferring the magnetic sensitive part to ferrite, and there is a problem that the manufacturing process becomes complicated accordingly.

  In addition to the transfer process described above, the conventional Hall element having the structure shown in FIGS. 7 and 8 performs magnetic amplification by directly vapor-depositing a magnetic sensitive part made of an InSb thin film on a ferrite substrate. However, in the case of using such a vapor deposition process, since two different kinds of materials are directly vapor deposited, there is a problem that the crystallinity of the magnetic sensitive portion is poor and it is difficult to maximize the characteristics of the magnetic sensor.

  Further, a substrate-like material such as GaAs or Si used for the magnetically sensitive portion has a problem that it is difficult to reduce the thickness and a magnetic amplification structure cannot be practically realized (the substrate thickness needs to be about 30 μm). In addition, the temperature characteristics of the magnetic sensor are almost determined by the size of the band gap of the material used for the magnetic sensing part, and InSb that is most often used as a Hall element is generally not good. However, those having good temperature characteristics such as GaAs and Si have a problem that the sensitivity as a sensor is low. Furthermore, ferrite has problems (chip missing) such as chipping (when chipped), and there is a limit to downsizing.

In consideration of such conventional problems, the present invention
1) Forming a magnetic amplification structure by a simple manufacturing process by forming a magnetic material by plating,
2) Realization of thinning of GaAs, Si, and the like through processes such as etching and polishing.

Also, instead of 2) above,
3) By heteroepitaxially growing the magnetic sensitive part (for example, growing GaAs on the Si substrate), the substrate part other than the magnetic sensitive part can be selectively etched, and as a result, the magnetic sensitive part can be made thinner. is there.

  On the other hand, those described in Patent Documents 1 and 2 described above perform magnetic amplification by transferring or directly depositing a magnetic sensitive part made of an InSb thin film on a ferrite substrate. There is no disclosure about the point that the magnetic amplification structure is formed by a simple manufacturing process by forming the body by plating.

  Further, although it has been disclosed in Patent Document 3 described above that a magnetic sensitive part made of a magnetic thin film constituting a magnetic sensor is formed of a CoFeNi or NiFe plated film, a magnetic material sandwiching the magnetic sensitive part is plated. Nothing is disclosed about the points formed by the processing, and neither the above-mentioned 2) and 3) are disclosed.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a small magnetic sensor having a magnetic amplification structure that improves the sensitivity of the magnetic sensor, high sensitivity, and good temperature characteristics, and its manufacture. It is to provide a method.

  The present invention has been made in order to achieve such an object, and the invention according to claim 1 has a structure in which both sides of the magnetic sensitive portion are sandwiched between magnetic bodies having a magnetic amplification function. In the magnetic sensor, the semiconductor thin film having the magnetic sensing portion provided on the substrate, the first underlayer provided on the front side of the magnetic sensing portion, and the magnetic provided on the first underlayer. A first magnetic body having an amplifying function; a second underlayer provided on the back side of the magnetic sensing portion on the substrate; and provided on the second underlayer, together with the first magnetic body And a second magnetic body having a magnetic amplification function, wherein the first magnetic body and the second magnetic body are formed by plating, and the magnetic sensitive portion is the first magnetic body. It is characterized by being sandwiched between a body and the second magnetic body.

  According to a second aspect of the present invention, in the first aspect of the present invention, a protective layer is provided between the magnetically sensitive portion and the first underlayer.

  The invention described in claim 3 is the invention described in claim 1 or 2, characterized in that a gap between the first magnetic body and the second magnetic body is 1 μm to 30 μm.

  According to a fourth aspect of the present invention, in the first, second, or third aspect of the invention, the magnetically sensitive portion is made of any one of GaAs, InAs, InSb, Si, and Ge.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the first and second magnetic bodies are made of permalloy or supermalloy (Fe-Ni alloy). It is characterized by.

  The invention according to claim 6 is the invention according to claim 5, wherein the first and second magnetic bodies are obtained by adding cobalt (Co) to permalloy or supermalloy (Fe-Ni alloy). It consists of things.

  The invention according to claim 7 is the invention according to any one of claims 1 to 4, wherein the first and second magnetic bodies are permendur (Fe-Co alloy) or sendust (Fe -Si-Al alloy).

  The invention according to claim 8 is characterized in that, in the invention according to any one of claims 1 to 7, the vicinity of the magnetically sensitive portion on the back side of the substrate is thinned.

  The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the first magnetic body is provided only in the vicinity of the magnetic sensing portion on the substrate surface side, and the second The magnetic material is provided only in the vicinity of the magnetic sensitive part on the back side of the substrate.

  According to a tenth aspect of the present invention, in the method of manufacturing a magnetic sensor having a structure in which both sides of the magnetic sensitive part are sandwiched between magnetic bodies having a magnetic amplification function, the magnetic sensitive part is provided on a substrate. Forming a semiconductor thin film; forming a first underlayer for plating on the front side of the magnetic sensitive portion; and forming a second underlayer for plating on the back side of the magnetic sensitive portion. And forming a first magnetic body having a magnetic amplification function on the first underlayer by plating, and forming a second magnetic body having a magnetic amplification function on the second underlayer by plating. And forming the magnetically sensitive portion between the first magnetic body and the plated layer of the second magnetic body.

  According to an eleventh aspect of the present invention, in the invention according to the tenth aspect, the magnetically sensitive portion sandwiched between the plated layers of the first magnetic body and the second magnetic body is etched or polished. And having a thickness of 1 μm to 30 μm.

  According to a twelfth aspect of the present invention, in the invention according to the tenth or eleventh aspect, a magnetic plating process is simultaneously performed on the first underlayer and the second underlayer. .

  According to a thirteenth aspect of the present invention, in the invention according to the tenth, eleventh or twelfth aspect, the protective layer is formed on the semiconductor thin film having the magnetically sensitive portion before the step of forming the first underlayer. It has the process of forming.

  According to a fourteenth aspect of the present invention, in the invention according to any one of the tenth to thirteenth aspects, after the first underlayer and the second underlayer are formed, the first underlayer is formed. And a step of forming a resist pattern in which at least one of the magnetically sensitive portions on the second underlayer is a gap.

  According to a fifteenth aspect of the present invention, in the invention of the fourteenth aspect, after the first magnetic body and the second magnetic body are formed, the resist pattern and the first magnetic body are formed. A step of removing the first underlayer other than the formed portion and / or the second underlayer other than the portion where the second magnetic body is formed.

  According to a sixteenth aspect of the invention, there is provided the magnetic sensor according to the fourteenth aspect, wherein the first underlayer and / or the second underlayer is removed and then a dicing process is performed. It has the process of separating into chips.

  According to a seventeenth aspect of the invention, there is provided the method according to any one of the tenth to sixteenth aspects, further comprising a step of thinning the vicinity of the magnetically sensitive portion on the back side of the substrate.

  According to an eighteenth aspect of the invention, in the invention according to any of the tenth to seventeenth aspects, the first magnetic body is formed only in the vicinity of the magnetic sensing portion on the substrate surface side, and the first And 2) forming a magnetic body only in the vicinity of the magnetic sensitive part on the back side of the substrate.

  Here, examples of the magnetic sensor include various sensors such as a Hall sensor formed by a semiconductor thin film and a magnetoresistive effect sensor (MR sensor).

  According to the present invention, the first magnetic body and the second magnetic body are plated layers formed by plating, and the magnetic sensitive part is sandwiched between the first magnetic body and the second magnetic body. Therefore, it is possible to obtain a magnetic amplification structure with a simple manufacturing process in which only magnetic material plating is performed, and there is an effect that a miniaturized and highly sensitive magnetic sensor can be realized.

  In addition, even if Si or GaAs with good temperature characteristics is used for the magnetic sensing part, it is possible to adopt a magnetic amplification structure that was not possible before, so a magnetic sensor with a small size, good temperature characteristics and high sensitivity can be obtained. There is an effect that it can be realized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram for explaining an embodiment of a magnetic sensor of the present invention, in which reference numeral 10 is a substrate, 11 is a semiconductor thin film, 11a is a magnetic sensitive part, 12 is a metal electrode, 13 is a protective layer, Reference numeral 14 denotes a first underlayer, 15 denotes a second underlayer, 17 denotes a first magnetic body, and 18 denotes a second magnetic body.

  The magnetic sensor of the present invention is a magnetic sensor having a structure in which both sides of the magnetic sensing part 11a are sandwiched between two magnetic bodies 17 and 18 having a magnetic amplification function. The semiconductor thin film 11 having the magnetic sensing part 11a is provided on the substrate 10, and metal electrodes 12 are provided at both ends of the magnetic sensing part 11a. Further, a first underlayer 14 is provided on the front side in the vicinity of the magnetic sensing portion 11a via a protective layer 13, and a first magnetic body 17 having a magnetic amplification function is provided on the first underlayer 14. Is provided. Furthermore, a second underlayer 15 is provided on the back side of the magnetic sensing part 11a on the substrate 10, and on the second underlayer 15, a second magnetic layer 17 having a magnetic amplification function together with the first magnetic body 17 is provided. A magnetic body 18 is provided.

  The magnetic sensor having such a structure includes a plated layer in which a first magnetic body 17 and a second magnetic body 18 are formed by a magnetic plating process, and the magnetic sensing portion 11a is a first magnetic body. 17 and the second magnetic body 18. For this reason, a magnetic amplification structure can be obtained by a simple manufacturing process in which only the magnetic material plating process is performed, and a small and highly sensitive magnetic sensor can be realized.

  Conventionally, in order to form a magnetic amplification structure that holds the magnetically sensitive portion with a magnetic material as described above, a method of transferring InSb formed on mica to a ferrite substrate, or vapor deposition of InSb on a ferrite substrate. However, in the present invention, since the magnetic material can be produced by performing the plating process regardless of the underlying substrate, Si or GaAs having good temperature characteristics is used for the magnetically sensitive portion. Even in such a case, a magnetic amplification structure can be formed, and a magnetic sensor with excellent temperature characteristics and high sensitivity that has never been achieved can be realized.

  Further, the protective layer 13 provided between the magnetic sensing part 11 a and the first underlayer 14 is formed by patterning polyimide on the semiconductor thin film 11. The gap between the first magnetic body 17 and the second magnetic body 18 is 1 μm to 30 μm.

  Further, the magnetic sensing part 11a is made of GaAs, InAs, InSb, Si, Ge, or a combination of the above compositions, and the first magnetic body 17 and the second magnetic body 18 are made of permalloy or super It is preferable to be made of malloy (Fe—Ni-based alloy), and the addition of cobalt (Co) to it is more preferable because the magnetic hysteresis is reduced. Furthermore, the first magnetic body 17 and the second magnetic body 18 can be formed of permendur (Fe—Co alloy) or sendust (Fe—Si—Al alloy).

  2A to 2D and FIGS. 3E to 3G are process cross-sectional views for explaining the method of manufacturing the magnetic sensor of the present invention.

First, the semiconductor thin film 11 having the magnetic sensitive portion 11a is formed on the substrate 10 made of Si or GaAs. The magnetic sensitive portion 11a is made of GaAs doped with impurities, and metal electrodes 12 are formed at both ends. The magnetic sensing portion 11a may be made of any of InAs, InSb, Si, and Ge in addition to GaAs (FIG. 2 (a); production of a magnetic sensor (Hall element) chip). Normally, a passivation film is formed of SiO ₂ or SiN on the magnetic sensitive part, but it is omitted in FIG. 2A for simplicity.

  Next, by patterning polyimide, a protective layer 13 made of polyimide is formed on the semiconductor thin film 11 having the magnetic sensitive portion 11a except for the metal electrode 12 portion (FIG. 2B; polyimide patterning). The formation of the protective layer 13 can be omitted depending on circumstances.

  Next, as a base layer for the plating process, a first base layer 14 is formed on the protective layer 13 and the metal electrode 12 and on the front side in the vicinity of the magnetic sensitive portion 11a, and on the substrate 10 and the magnetic sensitive portion 11a. A second underlayer 15 is formed on the back side (FIG. 2C; UBM (Under Bump Metal) formation). This underlayer is made of TiW / Cu and can be produced by sputtering or the like.

  Next, a resist 16 is formed on the first underlayer 14 by resist patterning so that the magnetic sensitive portion 11a becomes a void portion 16a except for the magnetic sensitive portion 11a (FIG. 2D); Resist pattern formation).

  Next, the first magnetic body 17 having a magnetic amplification function is formed in the gap 16 a on the first underlayer 14 removed by the resist patterning, and the first magnetic body 17 is magnetically formed on the second underlayer 15. A second magnetic body 18 having an amplification function is formed by plating (FIG. 3E; magnetic body plating).

  This magnetic body is made by plating an Fe—Ni alloy. The plating process of the first magnetic body in the gap portion 16a on the first underlayer 14 and the plating process of the second magnetic body on the second underlayer 15 are performed at the same time. The gap between the body 17 and the second magnetic body 18 is made to be 1 μm to 30 μm. In addition, the first magnetic body 17 and the second magnetic body 18 are preferably made of permalloy or supermalloy (Fe—Ni alloy), and the addition of Co to the first magnetic body 17 and the second magnetic body 18 reduces the magnetic hysteresis. preferable. Furthermore, the first magnetic body 17 and the second magnetic body 18 are preferably made of permendur (Fe—Co alloy) or sendust (Fe—Si—Al alloy).

  Next, the resist pattern 16 and the first underlayer 14 under the resist pattern 16 are removed (FIG. 3F; removal of the resist pattern and UBM). As a result, the first magnetic body 17 and the first underlayer 14 thereunder remain on the protective layer 13.

  Finally, a plurality of magnetic sensor (Hall element) chips are separated into single chips by dicing (FIG. 3G; dicing).

  The magnetic sensor thus manufactured is a plating layer in which the first magnetic body 17 and the second magnetic body 18 are formed by a magnetic plating process, and the magnetic sensitive portion 11a is the first magnetic body 17. And the second magnetic body 18. Therefore, the magnetic amplification structure can be formed by a simple manufacturing process in which only the magnetic plating is performed, and a small and highly sensitive magnetic sensor can be realized.

  In addition, as a technique for thinning a substrate such as GaAs or Si, an etching method or a polishing method can be used. In the magnetic sensor of the present invention, the semiconductor thin film 11 including the magnetic sensitive portion 11a is formed on the substrate 10, but the composition of the substrate 10 and the semiconductor thin film 11 is generally different. Therefore, the material of the substrate 10 can be easily etched, but the wet etching method using a solution that does not easily etch the semiconductor thin film 11 can be used. Further, when using the dry etching method, for example, there is an apparatus for etching while detecting the composition of the etched material, so that etching is stopped at the moment when only the substrate 10 is etched and the semiconductor thin film 11 is etched. It's easy to do. Even when the polishing method is used, it is possible to grind to about 10 μm with a diamond grindstone and further polish to about 5 μm with silicon oxide. In addition to the above, the magnetic sensitive part can be thinned to about 1 μm to 30 μm by using various methods.

  The semiconductor thin film 11 including the substrate 10 and the magnetic sensitive portion 11a is generally described as having a different composition. However, for example, when the GaAs thin film is formed on the Si substrate, the composition of the substrate and the thin film is used. However, by forming the magnetically sensitive portion using a heteroepitaxial growth method that is completely different, the etching selectivity can be further increased, and the magnetically sensitive portion can be made thinner as intended.

  In the above-described embodiment, the second magnetic body 18 is formed on one side on the back side of the substrate 10. However, as with the first magnetic body 17, not on the back side, for example, near the magnetic sensing portion 11 a. Of course, it is possible to form the second magnetic body 18 only on the back side, and the arrangement location of the magnetic body can be variously changed.

  Also, the substrate 10 does not need to be flat, and for example, as shown in FIG. 4, it is naturally possible to selectively reduce the thickness only on the back side in the vicinity of the magnetic sensitive portion 11a. As described above, the arrangement of the magnetic plating layer can be optimized as appropriate depending on the type of the magnetic sensor.

  In the example shown in FIG. 4, an example in which the substrate 10 is selectively thinned only on the back side in the vicinity of the magnetic sensing portion 11 a is shown. However, when the above-described heteroepitaxial growth method is used, as shown in FIG. The substrate 10 on the back side in the vicinity of the magnetic sensing portion 11a can be completely removed, and the gap between the first magnetic body 17 and the second magnetic body 18 can be further reduced.

  As a result of magnetic simulation of an example of the magnetic sensor of the present invention, when the magnetic sensor of the present invention is placed in an external magnetic field of 10 mT, as shown in FIG. It was measured. This means that the magnetic amplification function is 2.65 times. In this example, the calculation was performed assuming that the gap between the first magnetic body and the second magnetic body was 20 μm. When this gap is about 30 μm, the magnetic amplification function is about twice, and it is known that the magnetic amplification function is improved as the gap is reduced.

It is a block diagram for demonstrating one Embodiment of the magnetic sensor of this invention. (A) thru | or (d) are process sectional drawings (the 1) for demonstrating the manufacturing method of the magnetic sensor of this invention. (E) thru | or (g) are process sectional drawings (the 2) for demonstrating the manufacturing method of the magnetic sensor of this invention. It is a block diagram for demonstrating other embodiment of the magnetic sensor of this invention. It is a block diagram for demonstrating other embodiment of the magnetic sensor of this invention. It is a magnetic force line figure which shows the result of carrying out the magnetic simulation of an example of the magnetic sensor of this invention. It is a block diagram which shows the Hall element as a conventional magnetic sensor. It is a block diagram which shows the other example of the conventional Hall element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Substrate 11 Semiconductor thin film 11a Magnetosensitive part 12 Metal electrode 13 Protective layer 14 First underlayer 15 Second underlayer 16 Resist 16a Air gap 17 First magnetic body 18 Second magnetic body 22 Semiconductor thin film 22a Part 23 Metal electrode 31 First magnetic body 32 Semiconductor thin film 32a Magnetic sensing part 33 Metal electrode 34 Second magnetic body

Claims (18)

In the magnetic sensor having a structure in which both sides of the magnetic sensitive part are sandwiched between magnetic bodies having a magnetic amplification function,
A semiconductor thin film provided on a substrate and having the magnetically sensitive portion;
A first underlayer provided on the front side of the magnetic sensitive part;
A first magnetic body having a magnetic amplification function provided on the first underlayer;
A second underlayer provided on the back side of the magnetic sensitive part on the substrate;
A second magnetic body provided on the second underlayer and having a magnetic amplification function together with the first magnetic body;
The first magnetic body and the second magnetic body are plating layers formed by plating, and the magnetic sensitive part is sandwiched between the first magnetic body and the second magnetic body. Magnetic sensor characterized by the above.   The magnetic sensor according to claim 1, wherein a protective layer is provided between the magnetic sensitive part and the first underlayer.   3. The magnetic sensor according to claim 1, wherein a gap between the first magnetic body and the second magnetic body is 1 μm to 30 μm.   The magnetic sensor according to claim 1, wherein the magnetically sensitive portion is made of any one of GaAs, InAs, InSb, Si, and Ge.   The magnetic sensor according to any one of claims 1 to 4, wherein the first and second magnetic bodies are made of permalloy or supermalloy (Fe-Ni alloy).   The magnetic sensor according to claim 5, wherein the first and second magnetic bodies are made of permalloy or supermalloy (Fe—Ni alloy) added with cobalt (Co).   The said 1st and 2nd magnetic body consists of permendur (Fe-Co type alloy) or sendust (Fe-Si-Al type alloy), The Claim 1 thru | or 4 characterized by the above-mentioned. Magnetic sensor.   The magnetic sensor according to claim 1, wherein the vicinity of the magnetic sensing portion on the back side of the substrate is thinned.   The first magnetic body is provided only in the vicinity of the magnetic sensitive part on the front side of the substrate, and the second magnetic body is provided only in the vicinity of the magnetic sensitive part on the back side of the substrate. The magnetic sensor according to any one of 1 to 8. In the method of manufacturing a magnetic sensor having a structure in which both sides of the magnetic sensitive part are sandwiched between magnetic bodies having a magnetic amplification function,
Forming a semiconductor thin film having the magnetically sensitive portion on a substrate;
Forming a first underlayer for plating on the front side of the magnetic sensitive part;
Forming a second underlayer for plating on the back side of the magnetic sensitive part;
A first magnetic body having a magnetic amplification function is formed on the first underlayer by plating, and a second magnetic body having a magnetic amplification function is formed on the second underlayer by plating. A process,
A method of manufacturing a magnetic sensor, wherein the magnetically sensitive portion is sandwiched between plating layers of the first magnetic body and the second magnetic body.   2. The method according to claim 1, further comprising: etching or polishing the magnetically sensitive portion sandwiched between the first magnetic body and the second magnetic body to a thickness of 1 μm to 30 μm. A method for manufacturing the magnetic sensor according to claim 10.   12. The method of manufacturing a magnetic sensor according to claim 10, wherein a magnetic plating process is simultaneously performed on the first underlayer and the second underlayer.   The magnetic sensor according to claim 10, 11 or 12, further comprising a step of forming a protective layer on the semiconductor thin film having the magnetically sensitive portion before the step of forming the first underlayer. Production method.   After forming the first underlayer and the second underlayer, at least one of the resist on the first underlayer and the second underlayer so that the vicinity of the magnetically sensitive portion is a void. The method for manufacturing a magnetic sensor according to claim 10, further comprising a step of forming a pattern.   After forming the first magnetic body and the second magnetic body, the first underlayer and / or the second magnetic layer other than the portion where the resist pattern and the first magnetic body are formed. The method of manufacturing a magnetic sensor according to claim 14, further comprising a step of removing the second base layer other than the portion where the body is formed.   16. The magnetic sensor according to claim 15, further comprising a step of separating the magnetic sensor chips by performing a dicing process after removing the first base layer and / or the second base layer. Manufacturing method.   The method of manufacturing a magnetic sensor according to claim 10, further comprising a step of thinning a vicinity of the magnetically sensitive portion on the back side of the substrate. Forming the first magnetic body only in the vicinity of the magnetic sensing portion on the front side of the substrate, and forming the second magnetic body only in the vicinity of the magnetic sensing portion on the back side of the substrate. A method of manufacturing a magnetic sensor according to claim 10.

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