JP2009216390A - Triaxial magnetic sensing device, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact triaxial magnetic sensing device of high sensitivity and high reliability, allowing highly dense integration, and a manufacturing method therefor. <P>SOLUTION: This triaxial magnetic sensing device includes an X-axial thin-film magnetic sensor formed to have a magnetic sensitive axis along an X axis existing in a flat part on a surface of a substrate, a Y-axial thin-film magnetic sensor formed to have a magnetic sensitive axis along a Y axis with 90° with respect to the X axis, a recess having an inclined face provided to form a prescribed angle to the flat part on an upper face of the substrate, and a Z-axial thin-film magnetic sensor formed to have a magnetic sensitive axis along a Z axis extended perpendicularly to the surface of the substrate, the Z-axial thin-film magnetic sensor includes a magnetic detecting element and a magnetic induction member, the magnetic detecting element is formed in the flat part of the substrate surface, the magnetic induction member is formed in the inclined face, and the magnetic detecting element is coupled magnetically with the magnetic induction member. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a three-axis magnetic sensing device formed by arranging at least three or more thin film magnetic sensors on the same substrate, and in particular, a highly sensitive and highly reliable small size 3 that can be integrated at a high density. The present invention relates to an axial magnetic sensing device and a manufacturing method thereof.

Conventionally, a magnetoresistive effect element is known as a magnetic sensor, and includes an anisotropic magnetoresistive effect element (AMR element), a giant magnetoresistive effect element (GMR element), and a magnetic tunnel effect element (TMR element). ) The AMR element is composed of an MR film, and the resistance value of the MR film changes due to rotation of the magnetization of this film by an external magnetic field. Therefore, the direction of the external magnetic field can be detected from this output.
On the other hand, GMR elements and TMR elements are known to be able to detect magnetic field changes with higher sensitivity, and these magnetoresistive elements are pinned in which the magnetization direction is pinned (fixed) in a predetermined direction. And a free layer whose magnetization direction changes according to an external magnetic field, and shows a resistance value corresponding to the relative relationship between the magnetization direction of the pinned layer and the magnetization direction of the free layer as an output.
One such element is used to detect changes in the magnetic field in two orthogonal directions (herein, “two orthogonal directions” are referred to as “X-axis direction and Y-axis direction”). A technique for detecting the direction of an external magnetic field by arranging them so as to be orthogonal and obtaining the output of each element (change in resistance value) is known.

In recent years, mobile terminals have been improved in functionality and performance, and mobile phones equipped with a so-called navigation function for guiding to a desired position based on map information are rapidly spreading. For such applications, the convenience is dramatically improved by effectively utilizing geomagnetic information. Geomagnetism is a vector quantity, and its strength is generally said to be 0.3 to 0.5 Oe (Oersted) and is very weak.
In order to detect extremely weak geomagnetism with high accuracy in this way, improving the characteristics of the detection element itself is also an important technical problem. At the same time, the so-called three-axis x-axis, y-axis, and z-axis are also used. An important technical element is whether it can cope with detection of geomagnetism.
As is generally known, since the geomagnetism is due to the magnetic field lines generated from both magnetic poles on the earth, when detecting this geomagnetism on the earth that is not a plane, information only on the horizontal plane, that is, two-dimensional information. Needless to say, it is not enough. Therefore, in order to effectively use information relating to geomagnetism, it is necessary to detect geomagnetism information in three dimensions.

Conventionally, in order to solve such problems, a plurality of individually produced magnetic sensors are assembled and modularized so that one magnetic sensor detects the magnetism of one axis as a whole. Is known, that is, a three-axis magnetic sensing device formed by arranging at least three or more thin film magnetic sensors on the same substrate.
Specific examples of the conventional multi-axis magnetic sensing device or method include the following proposed examples.
As a first prior art, among a magnetic sensor in which a pair of thin film yokes are arranged via a gap and a GMR film is provided in the gap, the magnetosensitive axis of the Z-axis detection element is the surface of the substrate. There has been proposed one that detects magnetic information in the Z-axis direction by forming it on an inclined surface so as not to be parallel to (Patent Document 1).
As a second prior art, in a magnetic field detection apparatus that detects magnetic field components in two or three axial directions orthogonal to each other based on outputs of two or three magnetic sensors, the arrangement of two or three magnetic sensors is used. Specifically, the sensitivity direction of at least two of the two or three magnetic sensors is arranged obliquely with respect to the surface of the member on which the magnetic sensor is packaged. In this arrangement, it has been proposed that magnetic sensor components in three axial directions perpendicular to each other can be detected (Patent Document 2).

As a third prior art, the same three magnetoresistive films formed on the substrate are formed so that the magnetization directions intersect each other in a three-dimensional direction. Therefore, one magnetoresistive film is formed. Has been proposed which is formed on an inclined surface processed into a substrate (Patent Document 3).
As a fourth prior art, a high sensitivity is realized by forming a magnetic film in a tapered groove provided so as to coincide with the magnetoelectric conversion element and converging the magnetic flux on the magnetoelectric conversion element. Thus, it has been proposed that the magnetoelectric conversion element is formed in a flat portion and a magnetic film for converging the magnetic flux is formed in a tapered groove, that is, an inclined surface (Patent Document 4).
As a fifth prior art, for the purpose of increasing the sensitivity of the magnetic sensor, the magnetic sensor is formed using a TMR element or a GMR element, and is disposed on one surface of the element so that the coercive force is lower than the coercive force of the magnetic layer. In addition, a magnetic field sensing supplement soft magnetic film whose anisotropy axis is set independently of the anisotropy axis of the magnetic layer has been proposed (Patent Document 5).
JP 2004-354182 A JP-A-2005-249554 JP 2004-6752 A JP 2000-349363 A JP 2002-207071 A

However, in the prior art described in Patent Documents 2, 4, and 5, in order to generally set three axes, sensing is performed in order to assemble magnetic sensor elements corresponding to the x axis, the y axis, and the z axis. There is a limit to downsizing the entire device, especially in the height direction, and moreover, because multiple magnetic sensor elements are connected by wiring members and wires, long-term stability and reliability Had the problem of not being able to respond adequately.
Here, first, a technique generally proposed so far in order to realize a multi-axis magnetic sensor will be briefly described.

FIG. 7 shows that three magnetic sensors 101, 103, and 105 that detect changes in the magnetic field in the x-axis, y-axis, and z-axis directions are mounted on surfaces parallel to the x-axis, y-axis, and z-axis of the sensor support 100, respectively. This is a schematic view showing the state of assembly using technology and assembly so that three magnetic sensors can detect a three-dimensional magnetic field change.
In this way, magnetic information in three axial directions can be obtained, and when it is incorporated in a portable terminal or the like in which the location or posture to be used cannot be specified, very effective information can be obtained.
However, in this case, since three magnetic sensors that detect changes in the magnetic field in the x-axis, y-axis, and z-axis directions are assembled by mounting technology, the same degree can be obtained in any direction of the x-axis, y-axis, and z-axis. The size is required, and no matter how thin the magnetic sensor itself is, there is a problem that it cannot cope with the desired miniaturization at all. In particular, recent portable terminals have been rapidly reduced in size, thickness, and weight, and it is strongly desired that parts and devices that are difficult to be reduced be improved immediately.
As a solution to this problem, there has been proposed a technique for reducing the size by devising how to mount three magnetic sensors that detect magnetic field changes in the x-axis, y-axis, and z-axis directions.
That is Patent Document 2 introduced as the prior art. The contents of the technique will be described with reference to FIG. FIG. 8 is a schematic diagram showing how to mount three magnetic sensors that detect changes in magnetic fields in the x-axis, y-axis, and z-axis directions in the related art.

Here, as shown in FIG. 8, the three Hall elements (magnetic sensors) 201, 203, and 205 that detect changes in the magnetic field in the x-axis, y-axis, and z-axis directions are mounted 90 degrees orthogonal to each other. Instead, it is intended to reduce the size by arranging the substrate 200 at an angle of 90 degrees or less such as θa and θb.
However, since this conventional technology is a technology that realizes the correspondence of three axes by means of mounting that is arranged obliquely after forming individual elements individually, the effect of contributing to miniaturization is small, In addition, it is necessary to use mounting technology that uses wire bonding technology for the wiring connecting each magnetic sensor. In this respect as well, there is a limit to miniaturization, complexity of the process, ensuring temporal reliability, etc. Considering this point, it is a technology that needs improvement.
As a proposal of a technique different from the realization of the three-axis magnetic sensing device by the mounting technique described here, Patent Documents 1 and 3 are cited.
In these two patent documents, it is proposed not to realize three-axis support using mounting technology, but to realize a three-axis compatible magnetic sensing system by forming the magnetic sensor itself on an inclined surface. It is what. According to such a method, there is a possibility that downsizing and high reliability can be realized as compared with the method using the mounting technique.
However, the above-mentioned two prior arts (Patent Documents 1 and 3) are configured to form the magnetic sensor itself on an inclined surface, and thus involve great difficulty in producing the magnetic sensor itself. There are two main items, but these two points will be specifically described below.

The first point is about the surface property of the substrate. When manufacturing a magnetic sensor, particularly a magnetic sensor using a thin film laminated structure such as TMR or GMR, the thickness of each layer of the thin film laminated structure is an ultra-thin film of nanometer order, so that the underlying substrate is flat. Needless to say, sex becomes very important. In other words, if a thin film with a thickness of nanometer order is formed as a laminated structure on the order of micron order or submicron order, it is impossible to realize a thin film laminate structure as designed. Obviously, there arises a problem that the desired performance cannot be realized as a result. Thus, in order to realize a magnetic sensor using a thin film laminate structure having a film thickness of nanometer order, it is essential to achieve surface properties of nanometer order, preferably sub-nanometer order.
However, it is very difficult to process such inclined surfaces with nanometer order, preferably sub-nanometer order surface properties, and there is no realistic processing method that can be applied to mass production technology. Is the reality.

Another problem is related to microfabrication. A magnetic sensor using a thin film laminate structure such as TMR or GMR is characterized in that a general semiconductor formation process can be used. However, the general semiconductor formation process is not limited to a flat portion of a substrate. It has been developed on the premise of forming, and is not a manufacturing process that can be applied as it is to an inclined surface. Of course, as a fine processing technology that can form a three-dimensional structure, there is a technology that can be processed to some extent even if an object to be processed exists on an inclined surface represented by a MEMS technology or a micromachine technology.
However, in the photolithographic technique and the etching technique, which are indispensable techniques for the microfabrication technology on the inclined surface, it is difficult to uniformly coat the photoresist on the inclined surface, and the design value of the resist pattern dimension after the exposure As a result, a problem arises that it is impossible to obtain a magnetic sensor having the shape and dimensions as designed on the inclined surface.
The present invention has been made to solve such problems, and an object of the present invention is to provide a highly sensitive and highly reliable small multi-axis magnetic sensing device that can be integrated at a high density and a method for manufacturing the same. Is to provide.
Another object of the present invention is a high-sensitivity structure that can be integrated at a high density while having a structure in which an inclined surface of the substrate is effectively used when forming a multi-axis compatible magnetic sensor. Therefore, it is to provide a highly reliable small-sized multi-axis magnetic sensing device and a manufacturing method thereof.

  To achieve the above object, the invention described in claim 1 is a three-axis magnetic sensing device formed by disposing at least three or more thin film magnetic sensors on the same substrate, on the surface of the substrate. An X-axis thin film magnetic sensor formed on a flat portion on the surface of the substrate so that the X axis in the flat portion has a magnetosensitive axis; and 90 X relative to the X axis in the flat portion on the surface of the substrate. A Y-axis thin film magnetic sensor formed on a flat portion on the surface of the substrate so as to have a magnetosensitive axis on the Y-axis of °, and an inclination provided on the upper surface of the substrate so as to form a predetermined angle with the flat portion A concave portion having a surface, and a Z-axis thin film magnetic sensor formed on the flat portion on the surface of the substrate and the inclined surface so as to have a magnetosensitive axis in the Z-axis extending in a direction perpendicular to the surface of the substrate. The Z-axis thin film magnetic sensor is magnetic. The magnetic sensing element is formed on a flat portion of the substrate surface, the magnetic guiding member is formed on the inclined surface, and the magnetic sensing element and the magnetic guiding member are magnetized. It is characterized by being connected.

According to a second aspect of the present invention, the X-axis and Y-axis thin film magnetic sensor includes magnetic sensing elements each having a pinned layer and a free layer, and the pinned layer and the free layer of the X-axis and Y-axis thin film magnetic sensor. Each has an anisotropy shape that can define a long side and a short side, the long side directions are formed to be orthogonal to each other, and the directions of magnetization are also orthogonal to each other. The magnetic sensing element of the axial thin film geomagnetic sensor has a pinned layer and a free layer, and the magnetic induction member generates a magnetic field so that the magnetization directions of the pinned layer and the free layer in the Z axis thin film geomagnetic sensor are perpendicular to each other. It has a shape anisotropy to induce.
The invention according to claim 3 is characterized in that the magnetic sensing element is a TMR (Tunneling Magneto Resistance) element.
According to a fourth aspect of the present invention, the magnetic sensing element is a GMR (Giant Magneto Resistance) element.

The invention according to claim 5 is characterized in that the magnetic induction member of the Z-axis thin film magnetic sensor functions as a free layer.
The invention according to claim 6 is characterized in that the inclined surface is a (111) surface formed by anisotropic etching using a Si wafer on the substrate.
The invention according to claim 7 is a method of manufacturing a three-axis magnetic sensing device in which at least three or more thin film magnetic sensors are arranged on the same substrate, and the concave portion having an inclined surface is formed on the substrate. And an X-axis thin film magnetic sensor having a magnetosensitive axis on the X-axis on the flat part on the surface of the substrate, and a Y at 90 ° with respect to the X-axis on the flat part on the surface of the substrate A pinned magnetic film for forming a Y-axis thin film magnetic sensor having a magnetosensitive axis on the axis and a Z-axis thin film magnetic sensor having a magnetosensitive axis on the Z axis extending in a direction perpendicular to the surface of the substrate. Forming each layer, applying a magnetic field to the substrate from a predetermined direction, magnetizing, forming a free layer on each pinned layer, applying a magnetic field from the predetermined direction to the substrate Magnetizing step and the Z-axis thin film magnet Forming a magnetic induction member to magnetically couple with the free layer on the inclined surface at the sensor, and having a.

According to the present invention, since all the thin film magnetic sensors are formed on the flat portion of the substrate surface, the magnetic sensor according to the design dimensions can be formed with good reproducibility using a general semiconductor manufacturing process, and the Z axis Since the thin film magnetic sensor for detection is formed by magnetically coupling the magnetic induction member formed on the inclined surface, the magnetic detection element can detect the magnetism in the Z-axis direction while being flat. it can. Therefore, a small and highly accurate three-axis magnetic sensing device can be realized by a combination with the X-axis and Y-axis thin film magnetic sensors formed on the flat portion.
In addition, according to the present invention, since the shape and magnetization direction of the pinned layer and the free layer of each axis are orthogonal, magnetic detection can be performed with high sensitivity even in a weak magnetic field environment such as geomagnetism. A possible three-axis magnetic sensing device can be realized.
Further, according to the present invention, since the magnetic sensing element is a TMR (Tunneling Magneto Resistance) element, a highly sensitive and highly reliable triaxial geomagnetic sensing device can be realized.
Further, according to the present invention, since the magnetic sensing element is a GMR (Giant Magneto Resistance) element, a highly sensitive and highly reliable triaxial geomagnetic sensing device can be realized.
Further, according to the present invention, since the magnetic induction member of the Z-axis thin film magnetic sensor functions as a free layer, it is possible to simplify the manufacturing process and reduce the cost while maintaining the performance.
Further, according to the present invention, since the inclined surface is a (111) surface formed by anisotropic etching using a Si wafer as a substrate, a constant inclination angle can always be formed with good reproducibility, The magnetic field strength can be calculated based on the tilt angle that can be accurately calculated crystallographically, and magnetic information can be obtained with high accuracy.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, as a gist of the present invention, in a multi-axis magnetic sensing device, the detection part of the magnetic sensor itself is easy to ensure good surface properties, and fine processing as designed using a general semiconductor formation process is easy. Only for magnetic sensors that are formed on the flat part of the substrate and obtain magnetic information in a direction that is not parallel to the substrate, a magnetic induction member is formed on the inclined surface, and the magnetic information in a direction that is not parallel to the substrate. It is arranged to be magnetically coupled to the magnetic sensor for obtaining the sensor.
FIG. 1 is an explanatory view of an embodiment of a three-axis magnetic sensing device according to the present invention, in which an X-axis thin film magnetic sensor, a Y-axis thin film magnetic sensor, and a Z-axis thin film magnetic sensor are formed on a substrate. It is the top view shown.

As shown in FIG. 1, the three-axis magnetic sensing device includes a substrate 1 using a single crystal Si wafer and a substrate 1 having a magnetosensitive axis on the X axis in the flat portion 1a on the surface of the substrate 1. The X-axis thin film magnetic sensor 5 formed on the flat portion 1a on the surface and the flat portion on the flat portion 1a on the surface of the substrate 1 so as to have a magnetosensitive axis on the Y axis at 90 ° with respect to the X axis. A Y-axis thin film magnetic sensor 7 formed on 1 a, a recess 9 having an inclined surface 9 a provided on the upper surface of the substrate 1 so as to form an angle with the flat portion 1 a, and a direction perpendicular to the surface of the substrate 1 A flat portion 1a on the surface of the substrate 1 and a Z-axis thin film magnetic sensor 11 formed on the inclined surface 9a so as to have a magnetosensitive axis in the Z-axis extending in the direction.
The Z-axis thin film magnetic sensor 11 includes a magnetic detection element and a magnetic induction member. The magnetic detection element is formed on the flat portion 1a of the substrate surface, the magnetic induction member is formed on the inclined surface 9a, and the magnetic detection element. And the magnetic induction member are magnetically coupled.
The X-axis thin film magnetic sensor 5 is provided adjacent to the first side 9 a of the recess 9, and the Y-axis thin film magnetic sensor 7 has a positional relationship shifted by 90 degrees with respect to the X-axis thin film magnetic sensor 5. The Z-axis thin film magnetic sensor 11 is provided on the flat portion 1 a and the inclined surface 9 a adjacent to the third side 9 c of the recess 9.

2 is a cross-sectional view of the three-axis magnetic sensing device shown in FIG. 1, wherein (a) is a cross-sectional view taken along line BB ′ of FIG. 1, and (b) is a cross-sectional view taken along line AA of FIG. It is sectional drawing along a line.
As shown in FIGS. 1 and 2 (a) and 2 (b), the X-axis thin film magnetic sensor 5 and the Y-axis thin film magnetic sensor 7 have a TMR pinned layer + lower layers 5a and 7a and free layers 5b and 7b, respectively. It is formed of magnetic sensing elements joined via junction layers 5c and 7c, and each TMR pinned layer + lower layer 5a and 7a and free layers 5b and 7b are anisotropic capable of defining long sides and short sides. As shown in the figure, the long sides are formed so as to be orthogonal to each other. Further, as shown in the figure, the magnetization directions of the TMR pinned layer + lower layers 5a and 7a (shown by hatched arrows) and the magnetization directions of the free layers 5b and 7b (shown by white arrows) are also orthogonal to each other. Is formed.

As can be seen from FIG. 1, the X-axis thin film magnetic sensor 5 and the Y-axis thin film magnetic sensor 7 are formed so as to have a positional relationship shifted by 90 degrees. All components of the sensor 7 are formed on the flat portion 1 a on the substrate 1.
As shown in FIG. 1 and FIG. 2B, the Z-axis thin film magnetic sensor 11 includes a TMR pinned layer + lower layer 11a and a free layer 11b joined via a junction layer 11c. The inclined surface is formed in the flat portion 1a, and the magnetic induction member 11d is formed so as to be magnetically coupled to the magnetic sensing element, and the magnetic induction member 11d forms the recess 9 formed in the substrate. The structure is formed up to 9a. This is a major feature of the present invention. The magnetic induction member 11d also functions as the free layer 11b.
By configuring the Z-axis thin film magnetic sensor 11 in this way, it is possible to detect magnetism in the Z-axis direction even if the magnetic detection element itself is formed on a flat portion.
The TMR pinned layer + lower layer 5a, 7a of the X-axis thin film magnetic sensor 5 and the Y-axis thin film magnetic sensor 7 and the TMR pinned layer + lower layer 11a of the Z-axis thin film magnetic sensor 11 are insulated on the substrate 1. The film 13 is protected.

Next, how the thin film magnetic sensor of the three-axis magnetic sensing device having such a configuration functions will be described in detail below using a TMR element as an example.
FIG. 5 is an explanatory diagram schematically showing how the TMR element functions as a magnetoresistive element.
A TMR element has a basic structure in which a very thin insulating layer (such as an aluminum oxide layer or magnesium oxide) is sandwiched between a pinned layer and a free layer. When a TMR element is used as a magnetic sensor, Ir-Mn alloy-based and Co-Fe alloy-based laminates are often used, and as the free layer, a weakly magnetic Ni-Fe alloy system is often used.
The pinned layer has a fixed magnetization direction, while the free layer changes its magnetization direction following the direction of the external magnetic field. A phenomenon in which the resistance value varies greatly depending on the magnetization directions of the pinned layer and the free layer at this time is the magnetoresistive effect.

This will be described using the parallel state of FIG. 5A and the antiparallel state of FIG. The parallel state of FIG. 5A shows the case where the magnetization directions of the pinned layer and the free layer are parallel. In this case, as shown by the thick arrow A, the current easily flows, and the detected resistance The value is low resistance.
On the other hand, in the anti-parallel state in FIG. 5B, the current hardly flows as indicated by the thin arrow B, and the detected resistance value is high. In this way, the TMR element functions as a magnetic sensor because it can be detected as a large change in resistance value due to the difference in direction of the magnetization direction between the pinned layer and the free layer. As can be seen from this schematic diagram, the magnetization direction that can be detected by the TMR element has the highest sensitivity with respect to the component parallel to the film surface, and almost no magnetic field perpendicular to the film surface can be detected. Become.
In order to configure a magnetic sensing device for having sensitivity in the X-axis, Y-axis, and Z-axis directions to have such characteristics, the Z-axis magnetic sensor is the X-axis, Y-axis magnetic sensor. It is necessary to form on a surface that is not parallel to the surface. In order to realize this, a conventional technique has been proposed in which a Z-axis magnetic sensor is formed on an inclined surface, that is, a surface different from the X-axis and Y-axis magnetic sensors.

However, as described above, it is very difficult to form a magnetic sensor made of an extremely thin film such as a TMR element on an inclined surface.
Therefore, in the present invention, a magnetic sensor that requires good surface properties and high processing accuracy is formed on a flat portion, and a magnetic induction member that is magnetically coupled to the magnetic sensor is formed on an inclined surface, so that A magnetic sensor that functions in correspondence with the Z-axis is formed by guiding the magnetic field in the Z-axis direction to the magnetic sensor formed in the flat portion by utilizing the property that the magnetism is induced.
As described above, in this embodiment, the magnetic induction member 11d that receives the magnetic field in the direction perpendicular to the substrate 1 (Z-axis direction) induces the magnetic field to the free layer 11b constituting the magnetic sensor, and as a result, the magnetic sensor By converting a magnetic field perpendicular to the film surface into a component parallel to the magnetic sensor, a Z-axis magnetic sensor is realized.
In this magnetic sensor, the magnetization direction of the pinned layer and free layer is a very important factor, but the magnetization direction of each of the pinned layer and free layer can be controlled efficiently by using their shape anisotropy. It has the feature that a magnetizing process with excellent properties can be performed. This will be described below.

FIG. 3 is an explanatory view for explaining the magnetization process of the pinned layer. The same components will be described with the same reference numerals as in FIG. As shown in FIG. 3, here, the pinned layer is formed so as to have anisotropy. The anisotropy of the shape here is not limited to the rectangle as shown in FIG. 3 as long as the long side dimension and the short side dimension can be defined. As a specific example other than the rectangle, the effect of the present invention can be realized by an ellipse or a rhombus.
In FIG. 3, a recess 9 having an inclined surface 9 a is provided in the substrate 1, and a TMR pinned layer that becomes a part of the X-axis thin film magnetic sensor 5, the Y-axis thin film magnetic sensor 7, and the Z-axis thin film magnetic sensor 11 is formed around the recess 9. The lower layers 5a, 7a, and 11a are formed in the positional relationship as shown in the figure.
When a magnetic field is applied to the TMR pinned layer and the lower layers 5a, 7a, and 11a formed as described above in the direction indicated by the arrow D, the magnetic material of each TMR pinned layer is shaped. In order to have the characteristic of being magnetized by copying, they are magnetized in the directions indicated by the hatched arrows. That is, the pinned layer for the X-axis thin film magnetic sensor 5 and the pinned layer for the Y-axis thin film magnetic sensor 7 are magnetized in directions orthogonal to each other, and the pinned layer for the Z-axis thin film magnetic sensor 11 is used for the X-axis thin film magnetic sensor 5. It is magnetized in the same direction as the pinned layer.

FIG. 4 schematically shows a step of forming and magnetizing the free layer and the magnetic induction member after the pinned layer is magnetized in this way. The same components will be described with the same reference numerals as in FIG. FIG. 4 is an explanatory view schematically showing a process of forming and magnetizing the free layer and the magnetic induction member after the pinned layer is magnetized.
Here, as with the pinned layer, the free layer is formed so as to have anisotropy that can define the long side dimension and the short side dimension, but the important thing here is the long side of the pinned layer and the free layer. It is formed so that the direction is perpendicular. Since the X-axis thin film magnetic sensor 5 and the Y-axis thin film magnetic sensor 7 are formed on the flat portion 1a, it is not possible to form the pinned layers 5a, 7a and the free layers 5b, 7b so that the long side direction is simply perpendicular. Although there is no problem at all, the major feature of the present invention is that the free layer 11b for the Z-axis thin film magnetic sensor 11 and the magnetic induction member 11d magnetically coupled thereto are devised.
Specifically, the free layer 11b itself for the Z-axis thin film magnetic sensor 11 is formed so as to be substantially perpendicular to the pinned layer, and then magnetically coupled to the inclined surface 9a so as to be magnetically coupled to the free layer 11b. Form.
At this time, the shape of the magnetic induction member 11d formed on the inclined surface 9a is formed so as to have anisotropy, and the long side direction thereof is formed to be orthogonal to the long side direction of the pinned layer. After the free layers 5b, 7b, 11b and the magnetic induction member 11d are formed as shown in FIG. 4, when a magnetic field is applied in the direction indicated by the arrow shown as the magnetic field application direction D, each free layer 5b , 7b, 11b and the magnetic induction member 11d can be magnetized in the direction indicated by the arrows in the figure.
The magnetic induction member 11d magnetically coupled to the free layer 11b for the Z-axis thin film magnetic sensor 11 is also magnetized in the direction of the arrow in the figure due to its shape anisotropy, and the magnetization direction is the free layer 11b. As a result, the magnetization direction of the free layer 11b becomes the direction indicated by the dotted arrow, and is formed in a state of being magnetized in the direction orthogonal to the pinned layer.

Next, the manufacturing process of the triaxial magnetic sensing device will be described with reference to FIG. FIG. 6 is a flowchart of the manufacturing process of the triaxial magnetic sensing device shown in FIG.
Here, the thin film magnetic sensor for X, Y, and Z axes and the method of forming the magnetic induction member include a method using a stencil mask at the time of film formation, or forming a resist pattern in an area where a thin film material is unnecessary in advance. After the thin film material is formed on it, the lift-off method is used to select an appropriate region depending on the type of thin film material, such as a method of removing the thin film material in unnecessary regions together with the resist, a general dry etching method, or an Ar ion milling method. It can be done.
First, in step 101 of FIG. 6, a (100) single crystal Si wafer is used as the substrate 1, and first, in order to form the recess 9 having the inclined surface 9a, silicon nitride is formed in a region other than the portion where the recess 9 is formed. A film is formed, and using this as a mask, the Si wafer is anisotropically etched with KOH having a concentration of 32% and a temperature of 80 ° C. to form a concave portion 9 having an exposed inclined surface 9 a made of (111) plane. (See FIG. 3). Here, the inclined surface 9 a is inclined by about 45 ° with respect to the flat portion 1 a of the substrate 1. This inclination angle can be selected as appropriate.

Next, a thermal oxide film is formed on the entire substrate in order to maintain the insulating properties of the substrate surface on which the thin film magnetic sensor and the magnetic induction member are formed (step 103). Thermal oxidation is performed using a hot wall type thermal oxidation furnace under the conditions of an oxygen flow rate of 1 SLM and a temperature of 1100 degrees for 1.5 hours. Thus, the exposed surface of the substrate is entirely covered with the insulating film.
Next, an X-axis thin film magnetic sensor having a magnetosensitive axis on the X axis in the flat portion on the surface of the substrate 1, and a Y axis thin film magnetic sensor having a magnetosensitive axis on the Y axis at 90 ° to the X axis. In order to form a Z-axis thin film magnetic sensor having a magnetosensitive axis in the Z-axis extending in a direction perpendicular to the surface of the substrate, first, a TMR element is formed on the entire substrate surface by magnetron sputtering. For this purpose, a film made of aluminum is formed, and an aluminum film is formed and then oxidized by exposure to oxygen plasma. After forming a magnetic film other than the free layer, photolithography is performed using a photomask so as to obtain a desired shape, and then the magnetic film is finely processed using a dry etching technique (step 105). . At this time, the shapes of the TMR pinned layer and the lower layer were anisotropy capable of defining long side dimensions and short side dimensions as shown in FIG.
After each TMR pinned layer and lower layer are formed in such a shape, a magnetic field is applied to the substrate 1 from the direction indicated by the arrow D from the left (see FIG. 3), and in a vacuum set at a temperature of 300 ° C. Magnetization is performed (step 107). In this case, since the magnetic material has a characteristic of being magnetized following the shape, the magnetization direction of each TMR pinned layer can be controlled as shown in FIG.

Next, a free layer is formed on the pinned layer by the following method (step 109). As the free layer, Ni80-Fe20 permalloy alloy is used. It is formed by magnetron sputtering using a SUS304 stencil mask designed to obtain a desired shape. The desired shape here is a shape having anisotropy orthogonal to the previously formed TMR pinned layer, such as the free layers 5b, 7b, and 11b shown in FIG. Thereby, junction layers 5c, 7c, and 11c are formed between the free layers 5b, 7b, and 11b and the pinned layers 5a, 7a, and 11a (see FIG. 5).
After the free layer is formed in such a shape, a magnetic field is applied to the substrate 1 from the direction shown as the magnetic field application direction D in FIG. 4 (see FIG. 4), and magnetized in a vacuum set at a temperature of 240 ° C. Perform (step 111). Similar to the magnetization of each TMR pinned layer performed previously, it is magnetized following the shape, so that the magnetization direction of the free layer can be controlled as shown in FIG. By forming the TMR pinned layer and the free layer so that the shape anisotropies thereof are orthogonal to each other, the magnetization direction can be controlled so as to be orthogonal.

Next, the formation of the first interlayer insulating film, the formation of the first contact hole, the wiring and the pad portion are formed with aluminum, and finally, the Z-axis magnetic sensor is formed to form the magnetic induction member. Only the following steps are performed. A second interlayer insulating film is formed, and a magnetic induction member 11d is formed following the formation of the second contact hole (step 113). Here, the magnetic induction member 11d forms a Ni80-Fe20 permalloy alloy using a magnetron sputtering method using a SUS304 stencil mask. At this time, it is important that the magnetic induction member 11d is formed on the inclined surface 9a so as to be magnetically coupled to the free layer 11b of the Z-axis magnetic sensor 11. In the present embodiment, the inclined surface 9a is an inclined surface that is a part of the recess 9. However, the effect of the present invention can also be obtained by using a part of the inclined surface formed by film formation of an insulating material. Can be realized.
In the three-axis magnetic sensing device formed as described above, the signal output from the magnetic sensor for each axis at this time is subjected to arithmetic processing in consideration of the angle information of the Z-axis magnetic sensor 11, and three-dimensional Magnetic information was obtained correctly.

Next, a modification of the three-axis magnetic sensing device according to the present invention will be described.
The first modification is performed using a dry etching method when forming the recess. Similar to the above-described embodiment, a (100) single crystal Si wafer is used as the substrate 1, and in order to form the concave portion 9 (see FIG. 3) having an inclined surface, the film thickness is continuous in the region where the concave portion 9 is formed. The recess 9 having the inclined surface 9a is formed using a dry etching method using CF4 gas and hydrogen gas with the resist pattern formed to change as a mask.
The TMR element forming process and the magnetizing process after the formation of the recesses 9 are performed in the same manner as in the above-described embodiment, thereby forming magnetic sensors for each of the three axes.
Unlike the previous embodiment, the magnetic induction member 11d in the final process is formed by depositing a Ni80-Fe20 permalloy alloy on the entire surface using a magnetron sputtering method, and using a general photolithography or dry etching method. The three-axis sensing device is completed by forming the magnetic induction member 11d.
In the three-axis sensing device formed in this way, the signal output from the magnetic sensor for each axis at this time is subjected to arithmetic processing in consideration of the angle information of the Z-axis magnetic sensor 11, and three-dimensional magnetic I was able to get the information correctly. Next, another modification of the three-axis magnetic sensing device according to the present invention will be described.

This second modification uses a GMR element as a magnetic sensor. First, as in the above-described embodiment, a (100) single crystal Si wafer is used as the substrate 1, and the concave portion 9 having the inclined surface 9a composed of the (111) plane is formed by anisotropic etching using KOH. Thereafter, a silicon oxide film having a thickness of 800 nm is formed on the entire substrate including the concave portion 9 by plasma CVD using monosilane and hydrogen as source gases as an insulating film, and then the whole surface of the substrate is formed by GMR by magnetron sputtering. Magnetic films and nonmagnetic films for forming elements are alternately formed. In this modification, Co was used as the magnetic film and Cu was used as the nonmagnetic film. Each material is not limited to these, and can be appropriately selected from a magnetic material and a non-magnetic material. Further, a Ni80-Fe20 permalloy alloy was formed as a free layer on the outermost layer by magnetron sputtering.
Although a GMR element is used as the magnetic sensor, the shape is anisotropy as shown in FIG. 3 as in the above embodiment.
The magnetic induction member 11d in the final process is formed in the same manner as in the above embodiment. 11 d of magnetic induction members form the permalloy alloy of Ni80-Fe20 using the magnetron sputtering method using the stencil mask made from SUS304. In this way, a three-axis magnetic sensing device was completed. In this three-axis magnetic sensing device, the signal output from the magnetic sensor for each axis at this time is calculated in consideration of the angle information of the Z-axis magnetic sensor 11, and three-dimensional magnetic information is obtained correctly. I was able to.

Next, another modification of the three-axis magnetic sensing device according to the present invention will be described.
In the third modification, a TMR element is used as a magnetic sensor, but unlike the above embodiment, the shape having anisotropy is an ellipse. That is, the ratio of the major axis to the minor axis is 5: 1 for both the TMR pinned layer and the free layer. In this modification, the shape having anisotropy is an ellipse. However, other than this, for example, a polygon that can define a long side and a short side, and a long axis dimension and a short side even if the four sides have the same length. The effect of the present invention can be obtained by using a rhombus whose axial dimension can be defined.
In this modification, a (100) single crystal Si wafer is used as a substrate as in the above embodiment, and the Si wafer is anisotropically etched by KOH, and has an inclined surface 9a composed of an exposed (111) plane. A recess 9 is formed. Next, a thermal oxide film was formed on the entire substrate in order to maintain the insulation of the substrate surface.
Next, a magnetic film for forming a TMR element is formed on the entire substrate surface by magnetron sputtering. As the tunneling layer, an aluminum film formed and then oxidized by exposure to oxygen plasma is used. After forming a magnetic film other than the free layer, photolithography is performed using a photomask so that the above-described shape is obtained, and then fine processing of the magnetic film is performed using a dry etching technique. Form a magnetic sensor. In this way, a TMR element having an elliptical shape was formed.
Unlike the conventional method, the magnetic induction member in the final process is formed using a gas deposition method using Ni80-Fe20 permalloy alloy fine particles as a raw material. The gas deposition method is a technique in which a fine particle raw material is sprayed by a high-speed air flow to form a film on a substrate held in a vacuum, and the blowing nozzle and / or the substrate are moved in the XY direction. Thus, a pattern having a desired shape can be formed without a mask.

Further, in terms of film formation on an inclined surface as described in the present invention, a characteristic peculiar to the gas deposition method can be expected. That is, since the film forming method involves spraying the fine particle material onto the substrate, the desired shape can be obtained faithfully and easily even if the substrate is not flat. In the above embodiment, the permalloy alloy film serving as the magnetic induction member is formed using a stencil mask. In this case, however, the stencil mask and the inclined surface are not strictly in contact with each other, and the pattern resulting from the gap generated there is not formed. There is a possibility of blurring. The design of the pattern size and shape can alleviate the problem of this pattern blur to the extent that there is no problem in actual use. However, if a pattern shape that is more faithful to the design size is required, gas deposition The law is a very effective method.
In this way, a three-axis sensing device was completed. In this three-axis sensing device, the signal output from the magnetic sensor for each axis at this time is calculated in consideration of the angle information of the Z-axis magnetic sensor 11, and the three-dimensional magnetic information is obtained correctly. I was able to.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of an embodiment of a three-axis magnetic sensing device according to the present invention, and is a top view illustrating a state where an X-axis thin film magnetic sensor, a Y-axis thin film magnetic sensor, and a Z-axis thin film magnetic sensor are formed on a substrate. It is. FIG. 2 is a cross-sectional view of the three-axis magnetic sensing device shown in FIG. 1, where (a) is a cross-sectional view taken along line BB ′ in FIG. 1, and (b) is taken along line AA ′ in FIG. FIG. It is explanatory drawing explaining the magnetization process of the pinned layer. (A) (b) It is explanatory drawing which showed typically the process of forming and magnetizing a free layer and a magnetic induction member, after magnetizing a pinned layer. It is explanatory drawing which showed a mode that a TMR element functioned as a magnetoresistive element typically, (a) is a parallel state, (b) is an antiparallel state. It is a flowchart of the manufacturing process of the 3-axis magnetic sensing apparatus shown in FIG. Three magnetic sensors that detect changes in the magnetic field in the x-axis, y-axis, and z-axis directions are arranged on the surface of the sensor support parallel to the x-axis, y-axis, and z-axis, respectively, using mounting technology, and three magnetic sensors It is explanatory drawing which showed typically a mode that it assembled so that the change of a three-dimensional magnetic field could be detected with a sensor. It is a schematic diagram showing how to mount three magnetic sensors for detecting changes in magnetic fields in the x-axis, y-axis, and z-axis directions in the related art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 1a ... Flat part, 5 ... X-axis thin film magnetic sensor, 5a ... Pinned layer, 5a ... Lower layer, 5b ... Free layer, 5c ... Junction layer, 7 ... Y-axis thin film magnetic sensor, 7a ... Pinned layer, 7a ... Lower layer, 7b ... Free layer, 7c ... Junction layer, 9 ... Recess, 9a ... Inclined surface, 9b ... First side, 9c ... Second side, 9d ... Third side, 11 ... For Z-axis Magnetic sensor, 11a ... lower layer, 11b ... free layer, 11b ... rear free layer, 11c ... junction layer, 11d ... magnetic induction member, 13 ... insulating film

Claims (7)

A triaxial magnetic sensing device formed by arranging at least three or more thin film magnetic sensors on the same substrate,
An X-axis thin film magnetic sensor formed on the flat part so as to have a magnetosensitive axis in the X-axis on the flat part on the surface of the substrate;
A Y-axis thin film magnetic sensor formed in the flat part so as to have a magnetosensitive axis in a Y-axis of 90 ° with respect to the X-axis, which is in a flat part on the surface of the substrate;
A concave portion having an inclined surface provided on the upper surface of the substrate so as to form a predetermined angle with the flat portion;
A Z-axis thin film magnetic sensor formed on the flat portion and the inclined surface so as to have a magnetosensitive axis in the Z-axis extending in a direction perpendicular to the surface of the substrate;
The Z-axis thin film magnetic sensor includes a magnetic detection element and a magnetic induction member, the magnetic detection element is formed on the flat portion, the magnetic induction member is formed on the inclined surface, and the magnetic detection element and the A three-axis magnetic sensing device characterized in that a magnetic induction member is magnetically coupled.   The X-axis and Y-axis thin film magnetic sensors are each composed of a magnetic sensing element having a pinned layer and a free layer, and the pinned layer and the free layer of the X-axis and Y-axis thin film magnetic sensors define a long side and a short side, respectively. It has a shape having anisotropy that can be formed, and the long sides thereof are formed to be orthogonal to each other, and the directions of the respective magnetizations are also orthogonal, and the magnetic sensing element of the Z-axis thin film geomagnetic sensor includes: The magnetic induction member has a shape anisotropy that induces a magnetic field so that the magnetization directions of the pinned layer and the free layer in the Z-axis thin film geomagnetic sensor are perpendicular to each other. The three-axis magnetic sensing device according to claim 1.   The three-axis magnetic sensing device according to claim 2, wherein the magnetic sensing element is a TMR (Tunneling Magneto Resistance) element.   The three-axis magnetic sensing device according to claim 2, wherein the magnetic sensing element is a GMR (Giant Magneto Resistance) element.   The three-axis magnetic sensing device according to claim 2, wherein a magnetic induction member of the Z-axis thin film magnetic sensor functions as a free layer.   6. The triaxial magnetic sensing device according to claim 1, wherein the inclined surface is a (111) surface formed by anisotropic etching using a Si wafer on the substrate. A method of manufacturing a three-axis magnetic sensing device formed by arranging at least three or more thin film magnetic sensors on the same substrate,
Forming a recess having an inclined surface on the substrate;
An X-axis thin film magnetic sensor having a magnetosensitive axis on the X axis on a flat portion on the surface of the substrate; and a Y axis having a magnetosensitive axis on the Y axis at 90 ° with respect to the X axis. Forming a pinned layer comprising a magnetic film to form a thin film magnetic sensor and a Z axis thin film magnetic sensor having a magnetosensitive axis in the Z axis extending in a direction perpendicular to the surface of the substrate;
Magnetizing the substrate by applying a magnetic field from a predetermined direction;
Forming a free layer on each pinned layer;
Magnetizing the substrate by applying a magnetic field from a predetermined direction;
Forming a magnetic induction member on the inclined surface so as to be magnetically coupled to the free layer in the Z-axis thin film magnetic sensor.

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