JP2009020092A - Magnetic sensor and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic sensor that has a plurality of axes at the same time and can be produced in a small number of steps, and to provide a method of manufacturing the same. <P>SOLUTION: A pair of detecting sections in a plurality of sensor bridge circuits are arranged on a slope where the normal line directions of the inclination intersect with each other in a three-dimensional manner, and a pair of detecting sections in the same sensor bridge circuit are arranged on the slopes whose normal directions are the same. Accordingly, a pinned layer of the detecting section in the same bridge can be magnetized by once performing heat treatment in the magnetic field while applying a magnetic field of one direction, and the magnetizing direction of the pinned layer in each coordinate system can be magnetized in three magnetizing directions three-dimensionally crossing. Therefore, the number of producing steps can be reduced, and production yield is improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic sensor using a magnetoresistive element and a manufacturing method thereof.

Conventionally, as a sensor using various magnetoresistive elements, a magnetoresistive effect element (MR element), a magnetic impedance element (MI element), a fluxgate sensor, a semiconductor Hall effect sensor, and the like are used.
For example, according to the MI sensor, the use of a magnetoresistive element called an MI element facilitates thinning and miniaturization, and improvements are being actively made. In the case of an MR element, the magnetic field strength can be detected by a change due to the magnetic field of the high frequency impedance when a high frequency current is passed.

As a magnetic sensor element using a magnetoresistive effect element (MR element), a giant magnetoresistive effect element (GMR element), a tunnel magnetoresistive effect element (TMR element) and the like are known. In the GMR element, a plurality of ferromagnetic layers and non-ferromagnetic layers are alternately formed, and the magnetization directions of two adjacent magnetic layers are parallel or antiparallel depending on the strength of the external magnetic field. Magnetic detection is performed by using a resistance that changes in the above.
In addition, a TMR element is formed by forming a plurality of magnetic thin film layers through an insulating layer, and electrons related to conduction are conducted through the insulating layer by a tunnel phenomenon while maintaining spin, depending on the magnetization state at this time. Magnetic field detection is performed using the fact that the tunnel transmission coefficient is different.

  These magnetoresistive elements include a pinned layer (fixed layer) whose magnetization direction is fixed to a predetermined direction, and a free layer (free layer) whose magnetization direction changes according to the direction of the external magnetic field. When detecting an external magnetic field as a magnetic sensor, use the fact that the resistance value changes according to the relative relationship of the magnetization direction of the free layer that changes according to the direction of the external magnetic field with respect to the magnetization direction of the fixed pinned layer. The direction of the magnetic field is detected.

  By the way, in recent years, devices using GPS such as car navigation and mobile phone devices are increasing. Under such circumstances, there is a demand for an ultra-small magnetic sensor for use in confirming the current location in a place where radio waves from GPS are blocked. Therefore, a magnetic sensor made on a silicon wafer that can be integrated with an IC is advantageous. Further, it is required to detect the orientation of the magnetic sensor in a two-dimensional plane or a three-dimensional space.

There is a technique disclosed in Patent Document 1 as a magnetic sensor capable of detecting the orientation of a two-dimensional plane.
Further, Patent Document 2, Patent Document 3, and Patent Document 3 disclose magnetic sensors that can detect the orientation of a three-dimensional space.

  In the invention described in Patent Document 1, the magnetoresistive effect elements are arranged in a plane on the substrate so as to be orthogonal to each other so as to detect magnetic field changes in two orthogonal directions (X-axis direction and Y-axis direction). The Wheatstone bridge is connected by several magnetoresistive elements in each direction.

  The invention described in Patent Document 2 discloses a technique to which a TMR element is applied, and the TMR elements are arranged independently on three axes. The magnetic sensor for detecting the change in the uniaxial magnetic field is an explanatory diagram arranged on three axes orthogonal to each other using a mounting technique.

  In the invention described in Patent Document 3, a biaxial magnetic detection unit and a uniaxial detection unit composed of MR elements are formed on a flexible substrate, and the thin film conductor unit that electrically connects both detection units is flexible. A triaxial azimuth sensor is configured by bending a conductive substrate.

In the invention described in Patent Document 4, the magnetoresistive effect elements are arranged in a plane so as to be orthogonal to each other so as to detect magnetic field changes in two orthogonal directions (X-axis direction and Y-axis direction). Further, a magnetoresistive effect element is arranged on a slope formed on the substrate so as to detect a change in the magnetic field in the Z-axis direction. In addition, Wheatstone bridges are connected by several magnetoresistive elements in each direction.
Japanese Patent No. 3498737 JP 2003008101 A JP 2006-010591 A JP 2006-308573 A

  As a three-axis magnetic sensor, a three-axis magnetic sensor in which a single-axis magnetic sensor chip is mounted in three orthogonal directions as in the invention described in Patent Document 2, or two as in the invention described in Patent Document 3. There has been proposed a configuration in which a three-axis magnetic sensor is formed by forming a magnetic detection unit of a shaft and a detection unit of a single axis on a flexible substrate and bending a flexible base material.

  In the invention described in Patent Document 2, it is difficult to improve the accuracy of the orthogonality of each axis due to the three-dimensional mounting, and the routing of the electrical wiring is also complicated. Inevitably, this is a relatively large three-axis magnetic sensor. In the invention described in Patent Document 3, the relative position relationship of the magnetization direction of the pinned layer (fixed layer) of each axis can be made with high accuracy in the biaxial magnetic detection unit.

  On the other hand, the accuracy of the relative positional relationship in the magnetization direction between the biaxial magnetic detector and the uniaxial detector depends on how the flexible substrate is bent (bent). Therefore, the relative positional relationship in the magnetization direction between the biaxial magnetic detector and the uniaxial detector is less accurate than the positional relationship in the biaxial magnetic detector. Also, since a certain amount of paste is required to bend and fix the flexible base material, the base material for fixing the flexible base material becomes thicker and larger.

Thus, the variation in the relative position accuracy between the three axes leads to a decrease in the position accuracy read from the output of the measured external magnetic field.
Further, when mounting on a device such as a mobile phone, a small and thin sensor is required, but the inventions described in Patent Document 2 and Patent Document 3 have limitations. As a configuration example that solves the problems of the inventions described in Patent Documents 1 to 3, there is an invention described in Patent Document 4.

  As described above, the magnetic sensor using the magnetoresistive effect element (MR element) has a pinned layer (fixed layer) in which the magnetization direction is fixed to a predetermined direction, and the magnetization direction changes according to the direction of the external magnetic field. And a free layer (free layer). When detecting an external magnetic field as a magnetic sensor, use the fact that the resistance value changes according to the relative relationship of the magnetization direction of the free layer that changes according to the direction of the external magnetic field with respect to the magnetization direction of the fixed pinned layer. Therefore, the direction of magnetization of the pinned layer (fixed layer) differs in the optimum direction in a multi-axis sensor. The magnetization direction of the pinned layer is determined by heat treatment in a magnetic field at a predetermined temperature. Therefore, in a sensor having two or more axes on the same substrate, the pinned layer (fixed layer) is magnetized by changing the direction of the magnetic field for each axis (see Patent Document 1 and Patent Document 4).

The present invention has been made in view of such a problem, and the object of the present invention is to arrange a triaxial magnetic sensor on the same substrate so that the relative positional relationship of each axis becomes high accuracy, and the bridge. The reference resistance to be connected (resistance that shows a constant resistance value without being affected by the direction of the external magnetic field) is formed in the same substrate, and the pinned layers (fixed layers) of all axes are magnetized in one direction. It is an object of the present invention to provide a triaxial magnetic sensor that can be simultaneously formed by heat treatment in a magnetic field consisting of
That is, an object of the present invention is to provide a magnetic sensor having a small number of manufacturing steps and simultaneously having a plurality of axes, and a manufacturing method thereof.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a plurality of sensor bridge circuits in which a pair of detection units made of magnetoresistive elements and a pair of fixed resistors are bridge-connected on a substrate are formed, In the magnetic sensor formed so that the magnetization directions of the detectors cross each other in a three-dimensional direction, the substrate has a plurality of inclined surfaces in which the normal directions of the inclination cross three-dimensionally, and each sensor The pair of detection units in the bridge circuit are arranged on the same inclined surface.

  According to a second aspect of the present invention, a pair of detection units made of magnetoresistive elements on a substrate and a pair of fixed resistors having a constant resistance value without being affected by an external magnetic field are bridge-connected. A third sensor bridge circuit is formed, and in the first to third sensor bridge circuits, the magnetization direction of the detection unit is formed so as to intersect each other in a three-dimensional direction, the substrate is inclined Each of the detectors in the first to third sensor bridge circuits is arranged on an inclined surface where the normal direction of the inclination intersects three-dimensionally. And a pair of detection part in the same sensor bridge circuit is arranged on the inclined surface where the normal line direction of the inclined surface is the same.

  According to a third aspect of the present invention, a plurality of sensor bridge circuits in which a pair of detection units made of magnetoresistive elements and a pair of fixed resistors are bridge-connected are formed on a substrate, and the magnetization direction of the detection units is In a magnetic sensor formed so as to intersect with each other in a three-dimensional direction, it is made of a (100) single crystal silicon wafer, and a (111) direction crystal orientation plane that forms an inclination angle of about 55 ° with the substrate surface is an inclined plane. And the normal direction of the slope has an inclined surface that intersects three-dimensionally, and the pair of detection units in each sensor bridge circuit are arranged on the same inclined surface.

  According to a fourth aspect of the present invention, a pair of detection units made of a magnetoresistive effect element and a pair of fixed resistors having a constant resistance value without being affected by an external magnetic field are bridge-connected on the substrate. In a magnetic sensor in which a third sensor bridge circuit is formed and formed so that the magnetization directions of the detectors in the first to third sensor bridge circuits intersect each other in a three-dimensional direction, (100) single crystal A silicon wafer having an inclined surface in which a crystal orientation plane in the (111) direction that forms an inclination angle of about 55 ° with the substrate surface is an inclined surface and the normal direction of the inclined surface intersects three-dimensionally; The detection units in the third sensor bridge circuit are arranged on inclined surfaces where the normal directions of the inclination intersect three-dimensionally, and the pair of detection units in the same sensor bridge circuit have the same normal direction of the inclined surfaces. A slope Characterized in that arranged on.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the fixed resistor is composed of a magnetoresistive effect element composed of the same film type as the detecting portion, and is electrically insulated. It is characterized by being covered with a magnetic shield member through an insulating member from which can be obtained.

  A sixth aspect of the invention is characterized in that, in the invention of any one of the first to fifth aspects, the fixed resistor is arranged on an inclined surface formed on the substrate.

  The invention described in claim 7 is the invention according to any one of claims 1 to 6, wherein the magnetoresistive effect element is a tunnel magnetoresistive effect element.

  The invention according to claim 8 includes a step of preparing a substrate, a step of forming a plurality of inclined surfaces in which the normal directions of the inclination intersect three-dimensionally on the substrate, and a pair of detection units in each sensor bridge circuit Are arranged on the same inclined surface, and the magnetization of the pinned layer of the detection unit made of a magnetoresistive effect element is performed by applying a magnetic field from the vertical direction to the substrate surface while heating the entire substrate. And performing the process.

  According to a ninth aspect of the present invention, in the eighth aspect of the invention, the fixed resistor is a magnetoresistive effect element composed of the same film type as the detecting portion, and magnetically passes through an insulating member capable of obtaining electrical insulation. A step of covering with a shield member is provided.

  The invention described in claim 10 is characterized in that, in the invention described in claim 8 or 9, a tunnel magnetoresistive effect element is used as the magnetoresistive effect element.

  According to the present invention, a pair of detection units in a plurality of sensor bridge circuits are arranged on inclined slopes whose normal directions of inclination intersect three-dimensionally, and the pair of detection units in the same sensor bridge circuit are inclined slopes. The pinned layer of the detection unit in the same bridge is magnetized in the same direction by performing the heat treatment in the magnetic field only once while applying the magnetic field in one direction. In addition, since the magnetization directions of the pinned layers in each coordinate system can be magnetized in three magnetization directions that intersect three-dimensionally, the manufacturing process can be reduced, leading to an improvement in manufacturing yield. Further, since it can be integrally disposed on the same substrate, it can be made small and thin. By making it compact, the number of sensors that can be taken increases, leading to improved productivity.

  In one embodiment of the magnetic sensor according to the present invention, a plurality of sensor bridge circuits in which a pair of detection units made of magnetoresistive elements and a pair of fixed resistors are bridge-connected are formed on a substrate. In the magnetic sensor formed such that the magnetization directions intersect with each other in the three-dimensional direction, the substrate has a plurality of inclined surfaces in which the normal directions of the inclination intersect three-dimensionally, and each of the sensor bridge circuits The pair of detection units are respectively arranged on the same inclined surface.

  According to the above configuration, the substrate has a plurality of inclined surfaces in which the normal directions of the inclination intersect three-dimensionally, and the pair of detection units in each sensor bridge circuit are arranged on the same inclined surface, respectively. Therefore, the pinned layer of the detection unit in the same bridge can be magnetized in the same direction with only one heat treatment in the magnetic field while applying a magnetic field in one direction, and the magnetization direction of the pinned layer in each coordinate system Can be magnetized in three magnetization directions intersecting three-dimensionally, the manufacturing process can be reduced and the manufacturing yield can be improved. Further, since it can be integrally disposed on the same substrate, it can be made small and thin. By making it compact, the number of sensors that can be taken increases, leading to improved productivity.

  In another embodiment of the magnetic sensor according to the present invention, there is a pair of detection units made of magnetoresistive elements on a substrate and a pair of fixed resistors that exhibit a constant resistance value without being affected by an external magnetic field. Magnetic sensors are formed in which first to third sensor bridge circuits connected in a bridge are formed, and the magnetization directions of the detection units in the first to third sensor bridge circuits cross each other in a three-dimensional direction. The substrate has a plurality of inclined surfaces in which the normal direction of the inclination intersects three-dimensionally, and the detection unit in the first to third sensor bridge circuits is inclined so that the normal direction of the inclination intersects three-dimensionally. Each pair of detection units in the same sensor bridge circuit is arranged on the inclined surface having the same normal direction of the inclined surface.

  According to the above configuration, the substrate has a plurality of inclined surfaces in which the normal direction of the inclination intersects three-dimensionally, and the detection unit in the first to third sensor bridge circuits has the three-dimensional normal direction of the inclination. Each pair of detectors in the same sensor bridge circuit is arranged on an inclined surface having the same normal direction of the inclined surface, thereby applying a magnetic field in one direction. The pinned layer in the same bridge detector can be magnetized in the same direction with only one heat treatment in a magnetic field, and magnetized in three magnetization directions that three-dimensionally intersect the magnetization directions of the pinned layers in each coordinate system. Therefore, the manufacturing process can be reduced and the manufacturing yield can be improved. Further, since it can be integrally disposed on the same substrate, it can be made small and thin. By making it compact, the number of sensors that can be taken increases, leading to improved productivity.

  In another embodiment of the magnetic sensor according to the present invention, a plurality of sensor bridge circuits in which a pair of detection units composed of magnetoresistive elements and a pair of fixed resistors are bridge-connected on a substrate are formed. In a magnetic sensor formed such that the directions of magnetization intersect each other in a three-dimensional direction, the crystal orientation plane in the (111) direction is made of a (100) single crystal silicon wafer and forms an inclination angle of about 55 ° with the substrate surface. And the normal direction of the slope intersects three-dimensionally, and the pair of detection units in each sensor bridge circuit are respectively arranged on the same slope. .

  According to the above configuration, the substrate is made of a (100) single crystal silicon wafer, and has an inclined slope formed by a crystal orientation plane in the (111) direction that forms an inclination angle of about 55 ° with the substrate surface. A pair of detectors in the sensor bridge circuit are arranged on inclined slopes where the normal direction of the inclination intersects three-dimensionally, and the pair of detection parts in the same sensor bridge circuit have the same normal direction of the inclined slope. Since it is arranged on a certain slope, the pinned layer of the detection unit in the same bridge can be magnetized in the same direction with only one heat treatment in the magnetic field while applying a magnetic field in one direction, and each coordinate system Since the magnetization direction of the pinned layer can be magnetized in three magnetization directions that cross three-dimensionally, the manufacturing process can be reduced, leading to an improvement in manufacturing yield. Further, since it can be integrally disposed on the same substrate, it can be made small and thin. By making it compact, the number of sensors that can be taken increases, leading to improved productivity. Furthermore, since the slope on which the detector is arranged is defined by the crystal plane, the position accuracy of the detector between each axis is high, and the positional relationship between the three axes is uniquely determined by the crystal plane positional relationship, so there is Less stable production is possible.

  In another embodiment of the magnetic sensor according to the present invention, a pair of detection units made of magnetoresistive elements on a substrate and a pair of fixed resistors showing a constant resistance value without being affected by an external magnetic field are bridged. In the magnetic sensor in which the connected first to third sensor bridge circuits are formed, and the magnetization directions of the detection units in the first to third sensor bridge circuits are crossed in a three-dimensional direction. , (100) made of a single crystal silicon wafer, and has an inclined surface in which the (111) direction crystal orientation plane forming an inclination angle of about 55 ° with the substrate surface is inclined and the normal direction of the inclined surface intersects three-dimensionally. The detection units in the first to third sensor bridge circuits are respectively arranged on the inclined surfaces in which the normal directions of the inclinations intersect three-dimensionally, and the pair of detection units in the same sensor bridge circuit are the methods of the inclined surfaces. line Direction, characterized in that the arranged on the slopes are identical.

  According to the above configuration, the substrate is made of a (100) single crystal silicon wafer, and has an inclined slope formed by a crystal orientation plane in the (111) direction that forms an inclination angle of about 55 ° with the substrate surface. A pair of detectors in the sensor bridge circuit are arranged on inclined slopes where the normal direction of the inclination intersects three-dimensionally, and the pair of detection parts in the same sensor bridge circuit have the same normal direction of the inclined slope. Since it is arranged on a certain slope, the pinned layer of the detection unit in the same bridge can be magnetized in the same direction with only one heat treatment in the magnetic field while applying a magnetic field in one direction, and each coordinate system Since the magnetization direction of the pinned layer can be magnetized in three magnetization directions that cross three-dimensionally, the manufacturing process can be reduced and the manufacturing yield can be improved. Further, since it can be integrally disposed on the same substrate, it can be made small and thin. By making it compact, the number of sensors that can be taken increases, leading to improved productivity. Furthermore, since the slope on which the detector is arranged is defined by the crystal plane, the position accuracy of the detector between each axis is high, and the positional relationship between the three axes is uniquely determined by the crystal plane positional relationship, so there is Less stable production is possible.

  In another embodiment of the magnetic sensor according to the present invention, in addition to the above-described configuration, the fixed resistor is composed of a magnetoresistive effect element composed of the same film type as that of the detection unit, and an insulating member capable of obtaining electrical insulation is provided. It is covered with a magnetic shield member.

  According to the above configuration, since the fixed resistor is covered with the magnetic shield member via the insulating member that can be electrically insulated, even when an element having sensitivity to an external magnetic field such as a magnetoresistive effect element is provided. Since the magnetoresistive element is made of the same film type as that of the detection unit and functions as a fixed resistor without being affected by an external magnetic field, the temperature characteristics of the element can be made the same, and the magnetic sensor characteristics are stabilized.

  Another embodiment of the magnetic sensor according to the present invention is characterized in that, in addition to the above configuration, the fixed resistor is disposed on an inclined surface formed on the substrate.

  According to the above configuration, since the area occupied by the magnetic sensor can be reduced, the number of chips that can be cut out from the silicon wafer is increased, leading to cost reduction.

  Another embodiment of the magnetic sensor according to the present invention is characterized in that, in addition to the above configuration, the magnetoresistive element is a tunnel magnetoresistive element.

  According to the above configuration, since the magnetoresistive effect element is a tunnel magnetoresistive effect element, it is possible to detect the magnetism with less power consumption, and thus the global environmental load can be reduced.

  One embodiment of the method for manufacturing a magnetic sensor according to the present invention includes a step of preparing a substrate, a step of forming a plurality of inclined surfaces in which the normal directions of the inclination intersect three-dimensionally on the substrate, and each sensor bridge A step of arranging a pair of detection units in the circuit on the same inclined surface, and a pin of the detection unit composed of a magnetoresistive effect element by applying a magnetic field from the vertical direction to the substrate surface while heating the entire substrate And a step of magnetizing the layer.

  According to the above configuration, the magnetization of the pinned layer (fixing the magnetization direction) of the detection unit composed of the magnetoresistive effect element is performed by applying a magnetic field from the vertical direction to the substrate surface while heating the entire substrate. The detector can be magnetized in a single magnetizing process.

  In addition to the above-described configuration, another embodiment of the magnetic sensor manufacturing method of the present invention uses a magnetoresistive effect element composed of the same film type as that of the detection unit as a fixed resistor, and provides an insulating member that provides electrical insulation. A step of covering with a magnetic shield member is provided.

  According to the above configuration, the magnetoresistive effect element including the same film type as that of the detection unit is used as the fixed resistance, and the magnetic resistance member is provided with the step of covering with the magnetic shield member via the insulating member capable of obtaining electrical insulation. Even when an element having sensitivity to an external magnetic field such as a resistance effect element is provided, it functions as a fixed resistance without being affected by the external magnetic field, and is a magnetoresistive effect element composed of the same film type as the detection unit. The temperature characteristics of the elements can be made the same, and the magnetic sensor characteristics are stabilized.

  Another embodiment of the method for manufacturing a magnetic sensor of the present invention is characterized in that a tunnel magnetoresistive element is used as the magnetoresistive element in addition to the above configuration.

  According to the above configuration, magnetic detection can be performed with low power consumption, so that the global environmental load can be reduced.

  The above-described embodiment shows an example of a preferred embodiment of the present invention, and the present invention is not limited thereto, and various modifications can be made without departing from the scope of the invention. is there.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
<Example of detectors arranged on the same inclined surface with a certain angle>
Hereinafter, a magnetic sensor using the magnetoresistive effect element of this embodiment will be described with reference to the drawings. In addition, this invention is not limited to what is described in these Examples, It can change suitably in the range which does not deviate from the objective.

  FIG. 1 is an example of a configuration of a magnetic sensor in which the magnetoresistive effect element of the present embodiment is arranged by bridge circuit wiring, and is a diagram schematically showing a schematic plane. FIG. 2 is a schematic cross-sectional view in which a magnetoresistive effect element is arranged on the slope in the cross section taken along line II-II in FIG. 3 is the magnetoresistive effect element structure of FIG. 1, FIG. 3 (a) is the top view, FIG.3 (b) is the IIIb-IIIb sectional view taken on the line of FIG. FIG. 4 is a block diagram showing the bridge connection.

  The magnetic sensor 1 of the present embodiment includes two detection units 2A and 2B and two fixed resistance units 3A and 3B. The detection units 2A and 2B and the fixed resistance units 3A and 3B are TMR elements, and the film configurations of these elements are the same. A magnetic shield film is formed on the fixed resistance portions 3A and 3B so as not to have sensitivity to an external magnetic field. The configuration of the magnetic shield film will be specifically described in the third embodiment, and the description thereof is omitted here.

  The detection units 2A and 2B and the fixed resistance units 3A and 3B are formed on an inclined surface provided on the substrate 4, and the direction of magnetization is formed in the inclined surface, and the direction of sensitivity of magnetization is magnetoresistive. The direction of magnetization is determined so as to be in the direction intersecting the longitudinal direction of the effect elements (detecting portions 2A and 2B and fixed resistance portions 3A and 3B) and in the depth direction of the slope. The substrate 4 of the magnetic sensor 1 of this example was a (100) silicon wafer. The (100) silicon wafer has a silicon nitride film as an etching mask, and two grooves 5A and 5B are formed at a depth of 100 μm with a KOH solution (also applicable to a TMAH solution). The shape of the grooves 5A and 5B is composed of four inclined surfaces having an angle of about 55 ° with respect to the surface of the silicon wafer.

  In this embodiment, the groove bottom surface has a flat portion (a surface substantially parallel to the surface of the substrate 4), but the shape having no flat portion has no influence on the invention. Therefore, although not shown, it can be applied to a substrate having a V-groove structure that does not have a flat portion on the bottom surface of the groove. In the case of a V-groove structure that does not have a flat portion on the groove bottom surface, the area occupied by the magnetic sensor is narrowed by not having a flat portion on the groove bottom surface, so that further downsizing can be aimed at.

  Further, as shown in FIG. 1 of the present embodiment, the magnetoresistive effect element is formed long in the width direction with respect to the inclined surface, and by forming the magnetoresistive effect element only on the inclined surfaces facing each other, V Since the shape can be made close to the groove shape, it is advantageous for miniaturization of the magnetic sensor. The detection units 2A and 2B and the fixed resistance units 3A and 3B are connected to the bonding pads 7A, 7B, 7C, and 7D that are connected by the wiring 6 reflecting the bridge connection block diagram of FIG. A space is formed between the two grooves 5A and 5B so that the wiring 6 can be formed.

  In this embodiment, two grooves 5A and 5B are formed in the substrate 4. However, the etching mask is reversed so that these grooves become protrusions and processed with a KOH solution (also applicable to a TMAH solution). The substrate 4 can also be applied.

  However, since the wiring 6 and the bonding pads 7A to 7D are arranged on the etched plane, flatness of the etched plane is required. In addition to the (100) silicon wafer, a (110) silicon wafer, a semiconductor other than silicon, a glass material, a ceramic material, a nonmagnetic metal, etc. can be applied to the substrate used in the magnetoresistive effect element of this embodiment. is there. In the present embodiment, an inverted trapezoidal shape in which the top of a four-sided pyramid is cut off is applied.

  Among these substrates, the (100) silicon wafer employed in this example is stable in the (111) crystal plane at an inclination angle of about 55 ° with respect to the substrate surface by anisotropic wet etching using a KOH solution or the like. Therefore, the positional relationship between the detectors 2A and 2B is constant, and a highly reproducible manufacturing and a high manufacturing yield are obtained, so that the substrate configuration of the present invention is optimal.

Next, the bridge circuit will be described with reference to the bridge connection block diagram of FIG.
The resistors constituting the bridge circuit of the present embodiment are the detection units 2A and 2B formed on the same inclined surface and the fixed resistance units 3A and 3B formed respectively on two parallel surfaces with different slopes from the detection unit 2. Consists of.
In FIG. 4, R1 corresponds to the detector 2B, R2 corresponds to the fixed resistor 3A, R3 corresponds to the fixed resistor 3B, and R4 corresponds to the detector 2A. As described above, the magnetic sensor of this embodiment is configured as a bridge circuit, so that it is possible to detect a magnetic field with high accuracy by the null method that does not depend on fluctuations in the power supply voltage, input impedance or non-linearity of the detector. .

Next, a TMR element that is a magnetoresistive effect element will be described with reference to FIG.
The detection unit 2 </ b> A includes a free layer 21, a pinned layer 22, an insulating layer 23, a pinned layer side electrode 24, and a cap layer 25. In addition, the front and back surfaces are covered with an insulating thin film 26 and a passivation film 27 that maintain insulation from the substrate. In the passivation film 27, a pinned layer side contact hole 31 and a free layer side contact hole 32 for bonding wiring electrodes to the pinned layer side electrode 24 and the cap layer 25 are opened, and electric wiring is performed through these contact holes. (The wiring for electrical wiring is omitted in the figure). The free layer 21 is a layer in which the direction of magnetization changes according to the direction of the external magnetic field, while the pinned layer 22 is a layer in which the direction of magnetization is fixed regardless of the direction of external magnetization. The insulating layer 23 is sandwiched between the free layer 21 and the pinned layer 22 and serves as a tunnel layer.

As the TMR element, a pinned layer 22 composed of an antiferromagnetic material 22-1 such as Fe—Ni and a magnetic layer such as Co—Fe 22-2 is stacked on the substrate 4. Then, an insulating layer 23 is laminated on the pinned layer 22 and a free layer 21 is further laminated thereon. As the insulating layer 23, an insulating material such as SiO ₂ or a nonmagnetic metal oxide such as Al ₂ O ₃ or MgO is used. As the free layer 21, for example, Co—Fe, Fe—Ni, or the like can be used.
In addition, the magnetoresistive effect element is not limited to the TMR element, and a GMR element can also be used.

  FIG. 5 is a diagram schematically showing a schematic plane in an example of a three-axis magnetic sensor configuration in which three sets of one-axis magnetic sensors are arranged in combination. The three-axis magnetic sensor 1A of the present embodiment includes six detection units 2 (2A, 2B, 2C, 2D, 2E, 2F) and six fixed resistance units 3 (3A, 3B, 3C, 3D, 3E, 3F). A total of twelve bonding pads 7 are provided, and each bonding pad 7 and wiring 6 that electrically connects each detection unit 2 and each fixed resistance unit 3 are provided.

  The detection unit 2 and the fixed resistance unit 3 are TMR elements, and the film configurations of these elements are the same. The detection unit 2 and the fixed resistance unit 3 are formed on a slope provided on the substrate 4 and are formed so that the direction of magnetization is within the slope, and the direction of sensitivity of magnetization is a magnetoresistive element (detection). The direction of magnetization is determined so as to cross the longitudinal direction of the portion 2 and the fixed resistance portion 3) and to be the depth direction of the slope.

  The substrate 4 of the magnetic sensor 1A of this example was a (100) silicon wafer. The (100) silicon wafer has a silicon nitride film as an etching mask, and five grooves 5 (5A, 5B, 5C, 5D, 5E) are formed at a depth of 100 μm with a KOH solution (also applicable to a TMAH solution). . The shape of the groove 5 is composed of four inclined surfaces having an angle of about 55 ° with respect to the surface of the silicon wafer.

In this embodiment, the groove bottom surface has a flat portion (a surface substantially parallel to the surface of the substrate 104), but a shape having no flat portion has no effect on the present invention. Therefore, although not shown, it can be applied to a substrate having a V-groove structure that does not have a flat portion on the bottom surface of the groove. In the case of a V-groove structure that does not have a flat portion on the bottom surface of the groove, the area occupied by the magnetic sensor is narrowed and the size can be further reduced because the flat portion is not formed on the bottom surface of the groove.
Further, as shown in FIG. 1 of the present embodiment, the magnetoresistive effect element is formed long in the width direction with respect to the inclined surface, and by forming the magnetoresistive effect element only on the inclined surfaces facing each other, V Since the shape can be made close to the groove shape, it is advantageous for miniaturization of the magnetic sensor.

The detection units 2A and 2B function as a magnetic sensor in one axial direction, and a sensor bridge circuit combined with the fixed resistance units 3A and 3B is a circuit 1.
The detection units 2C and 2D function as a magnetic sensor in one axial direction, and a sensor bridge circuit combined with the fixed resistance units 3C and 3D is a circuit 2. The detection units 2E and 2F function as a magnetic sensor in one axial direction, and a circuit 3 is a sensor bridge circuit combined with the fixed resistance units 3E and 3F. The magnetization direction of the pinned layer 21 in the detection unit 2 is arranged differently in the magnetic sensors of the circuit 1, the circuit 2, and the circuit 3. The magnetization direction of the pinned layer 21 of the axis X and the axis Z is perpendicular to the axis Y on the paper surface, and the magnetization direction of the pinned layer 21 of the axis X and the axis Y is parallel and opposite on the paper surface. Have a relationship. That is, three-dimensionally, there is a positional relationship indicating the radiation directions in three directions at an angle of about 55 ° from the substrate surface.

<Another example in which detectors are arranged on the same inclined surface with a certain angle>
FIG. 14 is a diagram schematically showing a schematic plane in an example of the configuration of the magnetic sensor in which the magnetoresistive effect element of the present embodiment is arranged by bridge circuit wiring. FIG. 15 is a schematic cross-sectional view in which magnetoresistive elements are arranged on the slope in the cross section taken along the line XV-XV in FIG.
The magnetic sensor 301 of the present embodiment has a configuration in which the fixed resistor portion 303 of the first embodiment is formed on the same surface as the bonding pad 307 formation surface of the substrate 304, and has two detectors 302A and 302B and two fixed resistors. Parts 303A and 303B.

The detection units 302A and 302B and the fixed resistance units 303A and 303B are TMR elements, and the film configurations of these elements are the same. A magnetic shield film is formed on the fixed resistance portion 303 so as not to have sensitivity to an external magnetic field.
The configuration of the magnetic shield film will be specifically described in the fifth embodiment, and the description thereof is omitted here.
The detection units 302A and 302B are formed on a slope provided on the substrate 304, and are formed such that the direction of magnetization is within the slope, and the direction of sensitivity of magnetization is a magnetoresistive effect element (detection unit 302A, 302). 302B) is a direction intersecting with the longitudinal direction, and the magnetization direction is determined so as to be the depth direction of the slope.

The substrate 304 of the magnetic sensor 301 of this embodiment was a (100) silicon wafer. The (100) silicon wafer has a silicon nitride film as an etching mask, and a groove 305A is formed at a depth of 200 μm with a KOH solution (also applicable to a TMAH solution). The shape of the groove 305A is composed of four inclined surfaces having an angle of about 55 ° with respect to the surface of the silicon wafer.
In this embodiment, the bottom surface of the groove 305 has a flat portion (a surface substantially parallel to the surface of the substrate 304), but a V-groove structure having no flat portion (a surface substantially parallel to the surface of the substrate 304) is used. The groove 305 having no influence on the present invention. The detection units 302A and 302B and the fixed resistance units 303A and 303B are connected to the bonding pads 307A, 307B, 307C, and 307D that are connected by the wiring 306 reflecting the bridge connection block diagram of FIG.

In addition to the (100) silicon wafer, a (110) silicon wafer, a semiconductor other than silicon, a glass material, a ceramic material, a nonmagnetic metal, or the like can be applied to the substrate 304 used in the magnetoresistive effect element of this embodiment. .
Among these substrates, the (100) silicon wafer employed in this example is stable in the (111) crystal plane at an inclination angle of about 55 ° with respect to the substrate surface by anisotropic wet etching using a KOH solution or the like. Therefore, the positional relationship between the detectors 302A and 302B arranged on two different parallel slopes is constant, and a highly reproducible manufacturing and a high manufacturing yield can be obtained. It is.

Next, the bridge circuit will be described with reference to the bridge connection block diagram of FIG.
The resistors constituting the bridge circuit of the present embodiment are composed of detection portions 302A and 302B arranged on the same slope and fixed resistance portions 303A and 303B formed on a flat surface of the substrate 304, respectively. R1 corresponds to the detection unit 302B, R2 corresponds to the fixed resistance unit 303A, R3 corresponds to the fixed resistance unit 303B, and R4 corresponds to the detection unit 302A.
As described above, the magnetic sensor of this embodiment is configured as a bridge circuit, so that it is possible to detect a magnetic field with high accuracy by the null method that does not depend on fluctuations in the power supply voltage, input impedance or non-linearity of the detector. .
Although the TMR element is applied as the magnetoresistive effect element that constitutes the detection unit 302 and the fixed resistance unit 303 of the present embodiment, the description of the TMR element is omitted because it can have the same configuration as that of the first embodiment. To do.
Since the three-axis magnetic sensor configuration in which three sets of one-axis magnetic sensors are combined and arranged can be configured in the same manner as in the first embodiment by combining three sets of FIG. 14, description thereof will be omitted.
Also in this embodiment, the magnetoresistive effect element is not limited to the TMR element, and a GMR element can also be used.

(Effect of this embodiment)
Compared with the first embodiment by adopting a configuration in which the detection resistor 402 is arranged in a groove (which may be a protrusion) and the fixed resistor 303 is formed on the same surface as the upper bonding pad 307 formation surface of the substrate 304. Thus, the area occupied by the magnetic sensor 401 can be reduced. Therefore, the number of chips that can be cut out from the silicon wafer increases, leading to cost reduction.

<Example of the detector and the fixed resistor placed on the slope of one groove>
FIG. 16 is an example of a configuration of a magnetic sensor in which the magnetoresistive effect element of the present embodiment is arranged by bridge circuit wiring, and is a diagram schematically showing a schematic plane. FIG. 17 is a schematic cross-sectional view taken along line XVII-XVII in FIG.
The magnetic sensor 401 of the present embodiment has a configuration in which the fixed resistance portion 403 of the first embodiment is formed on the slope of the same groove as the detection portion 402, and has two detection portions 402A and 402B and two fixed resistance portions 403A and 403B. It has.
The detection units 402A and 402B and the fixed resistance units 403A and 403B are TMR elements, and the film configurations of these elements are the same. A magnetic shield film is formed on the fixed resistance portion 403 so as not to have sensitivity to an external magnetic field.

The configuration of the magnetic shield film will be specifically described in the fifth embodiment, and the description thereof is omitted here.
The detection units 402A and 402B are formed on a slope provided on the substrate 404, and are formed so that the direction of magnetization is within the slope, and the sensitivity direction of the magnetization is a magnetoresistive element (the detection unit 402A, 402B) is a direction intersecting the longitudinal direction, and the magnetization direction is determined so as to be the depth direction of the slope.
The substrate 404 of the magnetic sensor 401 of this embodiment is a (100) silicon wafer. In the (100) silicon wafer, a silicon nitride film is used as an etching mask, and a groove 405 is formed at a depth of 200 μm with a KOH solution (also applicable to a TMAH solution). The shape of the groove 405 is composed of four inclined surfaces having an angle of about 55 ° with respect to the surface of the silicon wafer.

In this embodiment, the bottom surface of the groove 405 has a flat portion (a surface substantially parallel to the surface of the substrate 404). However, a V-groove structure having no flat portion (a surface substantially parallel to the surface of the substrate 404) is used. Even the groove 405 has no effect on the present invention. The detection units 402A and 402B and the fixed resistance units 403A and 403B are connected to the bonding pads 407A, 407B, 407C, and 407D respectively connected to the input / output terminals by the wiring 406 reflecting the bridge connection block diagram of FIG.
There is a place where two wirings 406 intersect. Insulation is performed by forming an interlayer insulating film 409 so that the wirings are not in direct contact. A silicon oxide film using a plasma CVD apparatus is particularly suitable as the interlayer insulating film. The manufacturing method is not limited to this as long as it is an insulating interlayer film material other than the silicon oxide film.

In addition to the (100) silicon wafer, a (110) silicon wafer, a semiconductor other than silicon, a glass material, a ceramic material, a nonmagnetic metal, or the like can be applied to the substrate 404 used in the magnetoresistive effect element of this embodiment. .
Among these substrates, the (100) silicon wafer employed in this example is stable in the (111) crystal plane at an inclination angle of about 55 ° with respect to the substrate surface by anisotropic wet etching using a KOH solution or the like. Therefore, the positional relationship between the detectors 402A and 402B arranged on two different parallel slopes is constant, and a highly reproducible manufacturing and a high manufacturing yield can be obtained. It is.

Next, the bridge circuit will be described with reference to the bridge connection block diagram of FIG.
The resistors constituting the bridge circuit of the present embodiment are the fixed resistance portion 403A formed on the slope facing the detection portion 402 of the groove 405 constituting the slope where the detection portions 402A and 402B and the detection portion 402 are arranged on the same slope, respectively. , 403B. R1 corresponds to the detection unit 402B, R2 corresponds to the fixed resistance unit 403A, R3 corresponds to the fixed resistance unit 403B, and R4 corresponds to the detection unit 402A.

As described above, the magnetic sensor of this embodiment is configured as a bridge circuit, so that it is possible to detect a magnetic field with high accuracy by the null method that does not depend on fluctuations in the power supply voltage, input impedance or non-linearity of the detector. .
Although the TMR element is applied as the magnetoresistive effect element that configures the detection unit 402 and the fixed resistance unit 403 of the present embodiment, the TMR element can have the same configuration as that of the first embodiment, and thus the description thereof is omitted. To do.
A three-axis magnetic sensor configuration in which three sets of one-axis magnetic sensors are arranged in combination can take the configuration in which FIG. 16 is arranged in the same manner as in the first embodiment, and will not be described.
Also in this embodiment, the magnetoresistive effect element is not limited to the TMR element, and a GMR element can also be used.

(Effect of this embodiment)
By adopting the configuration of the present embodiment in which the groove (which may be a protrusion) in which the detection unit 402 and the fixed resistance unit 403 are arranged is one, the area occupied by the magnetic sensor 401 is larger than that of the first embodiment. Can be small. Therefore, the number of chips that can be cut out from the silicon wafer increases, leading to cost reduction. In addition, by making the fixed resistance unit 403 on the slope, the element characteristics such as the temperature characteristics of the detection unit 402 and the fixed resistance unit 403 can be made closer to those of the second embodiment. Therefore, magnetic field detection with higher accuracy is possible.

<Example of arranging two detectors on two parallel inclined slopes>
FIG. 6 is an example of a configuration of a magnetic sensor in which the magnetoresistive effect element of the present embodiment is arranged by bridge circuit wiring, and is a diagram schematically showing a schematic plane. FIG. 7 is a schematic cross-sectional view in which magnetoresistive elements are arranged on the slope in the cross section taken along line VII-VII in FIG. FIG. 8 is a block diagram showing the bridge connection.
The magnetic sensor 1 of the present embodiment has a configuration in which the positions of the detection unit 2 and the fixed resistance unit 3 of the first example are interchanged, and includes two detection units 102A and 102B and two fixed resistance units 103A and 103B. Yes.

The detection units 102A and 102B and the fixed resistance units 103A and 103B are TMR elements, and the film configurations of these elements are the same. A magnetic shield film is formed on the fixed resistance portion 103 so as not to have sensitivity to an external magnetic field.
The configuration of the magnetic shield film will be specifically described in the third embodiment, and the description thereof is omitted here.

  The detection units 102A and 102B and the fixed resistance units 103A and 103B are formed on a slope provided on the substrate 104, and the direction of magnetization is formed within the slope, and the direction of sensitivity of magnetization is magnetoresistive. The direction of magnetization is determined so as to be the direction intersecting the longitudinal direction of the effect elements (detecting portions 102A and 102B and fixed resistance portions 103A and 103B) and in the depth direction of the slope.

  The substrate 104 of the magnetic sensor 101 of this embodiment is a (100) silicon wafer. The (100) silicon wafer has a silicon nitride film as an etching mask, and two grooves 105A and 105B are formed at a depth of 200 μm with a KOH solution (also applicable to a TMAH solution). The shape of the grooves 105A and 105B is composed of four inclined surfaces having an angle of about 55 ° with respect to the surface of the silicon wafer.

  In this embodiment, a V-groove structure having no flat portion (a surface substantially parallel to the surface of the substrate 104) on the bottom surface of the groove 105 is used. However, the same flat portion as the first embodiment (substantially the same as the surface of the substrate 104). The groove 105 having a parallel plane) has no effect on the present invention. The detection units 102A and 102B and the fixed resistance units 103A and 103B are connected by the wiring 106 reflecting the bridge connection block diagram of FIG. A space between the two grooves 105A and 105B is formed by the wiring 106.

In addition to the (100) silicon wafer, a (110) silicon wafer, a semiconductor other than silicon, a glass material, a ceramic material, a nonmagnetic metal, or the like can be applied to the substrate 104 used in the magnetoresistive effect element of this embodiment. .
Among these substrates, the (100) silicon wafer employed in this example is stable in the (111) crystal plane at an inclination angle of about 55 ° with respect to the substrate surface by anisotropic wet etching using a KOH solution or the like. Therefore, the positional relationship between the detectors 102A and 102B arranged on two different parallel slopes is constant, and a highly reproducible manufacturing and a high manufacturing yield can be obtained. It is.

Next, the bridge circuit will be described with reference to the bridge connection block diagram of FIG.
The resistors constituting the bridge circuit of the present embodiment are composed of detection units 102A and 102B arranged on two different parallel inclined surfaces, and fixed resistance units 103A and 103B formed on different inclined surfaces of the detection unit 102, respectively. R1 corresponds to the detection unit 102B, R2 corresponds to the fixed resistance unit 103A, R3 corresponds to the fixed resistance unit 103B, and R4 corresponds to the detection unit 102A.

As described above, the magnetic sensor of this embodiment is configured as a bridge circuit, so that it is possible to detect a magnetic field with high accuracy by the null method that does not depend on fluctuations in the power supply voltage, input impedance or non-linearity of the detector. .
Although the TMR element is applied as the magnetoresistive effect element that constitutes the detection unit 102 and the fixed resistance unit 103 of the present embodiment, the TMR element can have the same configuration as that of the first embodiment, and thus the description is omitted. To do.

  Also in this embodiment, the magnetoresistive effect element is not limited to the TMR element, and a GMR element can also be used.

  FIG. 9 is a diagram schematically showing a schematic plane in an example of a three-axis magnetic sensor configuration in which three sets of one-axis magnetic sensors are arranged in combination. The three-axis magnetic sensor 101A of this embodiment includes six detection units 102 (102A, 102B, 102C, 102D, 102E, 102F) and six fixed resistance units 103 (103A, 103B, 103C, 103D, 103E, 103F). And a total of twelve bonding pads 107, and further, each bonding pad 107 and wiring 106 for electrically connecting each detection unit 102 and each fixed resistance unit 103.

  Note that the detection unit 102 and the fixed resistance unit 103 are TMR elements, and the film configurations of these elements are the same. The detection unit 102 and the fixed resistance unit 103 are formed on an inclined surface provided on the substrate 104, and the magnetization direction is formed in the inclined surface, and the sensitivity direction of the magnetization is a magnetoresistive effect element (detection). The direction of magnetization is determined so as to cross the longitudinal direction of the portion 102 and the fixed resistance portion 103) and to be the depth direction of the slope.

The substrate 104 of the magnetic sensor 101A of this embodiment is a (100) silicon wafer.
The (100) silicon wafer has a silicon nitride film as an etching mask, and five grooves 105 (5A, 5B, 5C, 5D, 5E) are formed at a depth of 200 μm with a KOH solution (also applicable to a TMAH solution). . The shape of the groove 5 is composed of four inclined surfaces having an angle of about 55 ° with respect to the surface of the silicon wafer. In this embodiment, a V-groove structure having no flat portion (a surface substantially parallel to the surface of the substrate 104) on the bottom surface of the groove 105 is used. However, the flat portion (substantially parallel to the surface of the substrate 104) as in the first embodiment is used. The groove 105 having a flat surface has no influence on the present invention.

The detection units 102A and 102B function as a magnetic sensor in one axial direction, and a sensor bridge circuit combined with the fixed resistance units 103A and 103B is a circuit 1.
The detection units 102C and 102D function as a magnetic sensor in one axial direction, and a sensor bridge circuit combined with the fixed resistance units 103C and 103D is a circuit 2. The detection units 102E and 102F function as a magnetic sensor in one axial direction, and a sensor bridge circuit combined with the fixed resistance units 103E and 103F is a circuit 3.

  The magnetization directions of the pinned layer 21 (the pinned layer 21 of the TMR element having the same configuration as that of the first embodiment) in the detection unit 102 are arranged differently in the magnetic sensors of the circuit 1, the circuit 2, and the circuit 3. The magnetization direction of the pinned layer 21 of the circuit 1 and the circuit 3 is perpendicular to the paper surface with respect to the circuit 2, and the magnetization direction of the pinned layer 21 of the circuit 1 and the circuit 2 is parallel and opposite to the paper surface. Have a relationship. That is, three-dimensionally, there is a positional relationship indicating the radiation directions in three directions at an angle of about 55 ° from the substrate surface.

  As described above, the first and second embodiments are representatively shown. However, if the magnetization direction of the pinned layer 21 is different in each of the circuit 1, the circuit 2, and the circuit 3, the detection unit (2, 102) and the fixed resistance layer The arrangement of (3, 103) on the slope may not necessarily be the arrangement of the first and second embodiments.

<Example of magnetic shield film configuration>
FIG. 10 is a diagram schematically illustrating a schematic plane of the magnetic sensor according to the present embodiment, and is an explanatory diagram for describing the fixed resistance portion provided with the magnetic shield film according to the first embodiment.
In this embodiment, the first embodiment is taken as an example, but the present invention can be similarly applied to the second embodiment. FIG. 11 is a cross-sectional view taken along the line XI-XI of FIG. 10, and is a cross-sectional view of the fixed resistance portion in which the magnetic shield film is arranged in the first embodiment (FIG. 3B).

  The magnetic sensor 201 of this embodiment includes two detection units 202A and 202B and two fixed resistance units 203A and 203B. The detection units 202A and 202B and the fixed resistance units 203A and 203B are TMR elements, and the film configurations of these elements are the same. The fixed resistance portion 203 is formed with a magnetic shield film through an insulating thin film. The fixed resistor 203 is thus formed with a magnetic shield film so as not to be sensitive to an external magnetic field.

Next, a TMR element that is a magnetoresistive element will be described with reference to FIG.
The fixed resistance portion 203A includes a free layer 221, a pinned layer 222, an insulating layer 223, a pinned layer side electrode 224, a cap layer 225, a wiring electrode 235, a lower magnetic shield film 241, an upper magnetic shield film 242, each magnetic shield film (241 , 242) and the electrodes (224, 235), an insulating thin film (228, 229) that keeps insulation between the electrodes, an insulating thin film 226 that keeps insulation from the substrate, and a passivation film 227.

In the passivation film 227, a pinned layer side contact hole 231 and a free layer side contact hole 232 for bonding the wiring electrode 235 to each of the pinned layer side electrode 224 and the cap layer 225 are opened, and electrical wiring is made through these contact holes. Is done.
The free layer 221 is a layer whose magnetization direction changes according to the direction of the external magnetic field, while the pinned layer 222 is a layer whose magnetization direction is fixed regardless of the direction of external magnetization. The insulating layer 223 is sandwiched between the free layer 221 and the pinned layer 222 and serves as a tunnel layer.
However, since the front and back surfaces of the free layer 221 are covered with the magnetic shield films (241, 242), the sensitivity due to the external magnetic field cannot be obtained.

As the TMR element, a pinned layer 222 composed of an antiferromagnetic material 222-1 such as Fe—Ni and a magnetic layer such as Co—Fe 222-2 is stacked on a substrate 204, for example. Then, an insulating layer 223 is laminated on the pinned layer 222, and a free layer 221 is further laminated thereon. As the insulating layer 223, an insulating material such as SiO ₂ or a nonmagnetic metal oxide such as Al ₂ O 3 or MgO is used. As the free layer 221, for example, Co—Fe, Fe—Ni, or the like can be used.

  In addition, the magnetoresistive effect element is not limited to the TMR element, and a GMR element can also be used. As in this example, the detection part and the fixed resistance part constituting the sensor bridge circuit are made of the same material and layer structure, and only the fixed resistance part is covered with a magnetic shield film through an insulating thin film, thereby detecting Since the temperature characteristics of the part and the fixed resistance part can be made the same, variations in characteristics due to the environmental temperature can be suppressed.

Here, a method for forming a magnetoresistive effect element used in the magnetic sensor 201 of this embodiment will be described.
FIG. 12 is a part of a flowchart showing a method for manufacturing a magnetic sensor according to the present invention, and FIG. 13 is the rest of the flowchart showing a method for manufacturing a magnetic sensor according to the present invention.
In this embodiment, it is assumed that a desired inclined surface is previously formed on the substrate.

First, an insulating thin film (silicon oxide film or the like) is formed on the substrate on which the inclined surface is formed (step S101).
A magnetic shield film such as a Ni—Fe alloy film, a Si—Fe alloy film, or a Fe—Ni—Mn—Cu alloy film is formed (step S102).
The formed magnetic shield film is subjected to photolithography / etching to remove at least the magnetic shield film in the vicinity of the position where the detector is disposed (step S103).
An insulating thin film (silicon oxide film or the like) is formed (step S104).
Each film having a desired layer structure to be a magnetoresistive element is formed (step S105).
Each of the deposited layers is subjected to a photolithographic etching process twice to form a two-stage pattern shape (step S106).

Then, an insulating protective layer is formed on the patterned element (step S107). Contact holes are formed in the protective layer by photolithography / etching (step S108).
A nonmagnetic metal film for wiring and bonding pads is formed on the entire surface of the substrate so as to cover the contact hole (step S109).

A bonding pad metal for connecting between the contact holes and the input / output terminals is formed by a photolithography / etching process (step S110).
An insulating thin film (silicon oxide film or the like) is formed (step S111).
A magnetic shield film such as a Ni-Fe alloy film, a Si-Fe alloy film, or a Fe-Ni-Mn-Cu alloy film is formed on the surface of the insulating thin film on the substrate surface side (surface on which the magnetoresistive effect element is formed). (Step S112).
The magnetic shield film is left so as to cover the fixed resistance portions 3A and 3B, and other regions are removed by photolithography / etching (step S113).
The insulating thin film on the bonding pad metal is removed by photolithography and etching (step S114).

Next, annealing in a magnetic field is performed to determine the direction of the pinned layer (step S115).
At this time, the magnetic field application direction is set to be perpendicular to the substrate surface. When used as a uniaxial sensor as in this embodiment, any direction other than perpendicular to the inclined surface may be used.
After the magnetization direction of the pinned layer is determined, annealing in a magnetic field is performed again at a temperature lower than that in step S115 to determine the direction of the free layer (step S116).

  The magnetic field application direction in this step is applied so as to be parallel to the substrate surface. At this time, since the magnetization direction of the pinned layer is determined in step S115, the direction is not changed. As described above, since the pinned layer of the detection unit composed of the magnetoresistive effect element is magnetized (the magnetization direction is fixed) by applying a magnetic field from the direction perpendicular to the substrate surface while heating the entire substrate, the magnetization is fixed once. Magnetization of the detection part can be performed in the magnetic process.

  As described above, the (100) silicon wafer formed on the substrates (4, 104, 204, 304, 404) of Examples 1 to 5 is used, and the shape of the grooves (5, 105, 205, 305, 405) is the same as that of the silicon wafer. It consists of four slopes with an angle of about 55 ° to the surface. However, the inclination angle may be an arbitrary angle as long as it is an angle other than the horizontal, and a projection other than the groove is also applicable. In addition to the (100) silicon wafer, a (110) silicon wafer, a semiconductor other than silicon, a glass material, a ceramic material, a non-magnetic metal, and the like can also be used as the substrate material (also described in each example). If a (100) silicon substrate is used, its crystal orientation plane of 54.7 ° (about 55 °) is convenient.

[Function and effect]
A pair of detectors in the first to third sensor bridge circuits are respectively arranged on an inclined slope whose normal direction of the inclination intersects three-dimensionally, and the pair of detectors in the same sensor bridge circuit is an inclined slope method. Since it is arranged on the slope with the same linear direction, the pinned layer of the detection unit in the same bridge can be magnetized in the same direction only by performing the heat treatment in the magnetic field once while applying the magnetic field in one direction, In addition, since the magnetization directions of the pinned layers in each coordinate system can be magnetized in three magnetization directions that intersect three-dimensionally, the manufacturing process can be reduced, leading to an improvement in manufacturing yield. Further, since it can be integrally disposed on the same substrate, it can be made small and thin. By making it compact, the number of sensors that can be taken increases, leading to improved productivity.

  The substrate is made of a (100) single crystal silicon wafer, has an inclined slope formed by a crystal orientation plane in the (111) direction that forms an inclination angle of about 55 ° with the substrate surface, and a pair in the first to third sensor bridge circuits. The detectors are placed on the slopes where the normal direction of the slope intersects three-dimensionally, and the pair of detectors in the same sensor bridge circuit are placed on the slope where the normal directions of the slopes are the same. Therefore, the pinned layer in the same bridge detection unit can be magnetized in the same direction and the magnetization direction of the pinned layer in each coordinate system can be magnetized only by performing heat treatment in a magnetic field while applying a magnetic field in one direction. Since it can be magnetized in three magnetization directions that intersect three-dimensionally, the manufacturing process can be reduced, leading to an improvement in manufacturing yield.

  Further, since it can be integrally disposed on the same substrate, it can be made small and thin. By making it compact, the number of sensors that can be taken increases, leading to improved productivity. Furthermore, since the slope on which the detector is arranged is defined by the crystal plane, the position accuracy of the detector between each axis is high, and the positional relationship between the three axes is uniquely determined by the crystal plane positional relationship, so there is Less stable production is possible.

  Since the fixed resistor is covered with a magnetic shield member through an insulating member that can be electrically insulated, even if an element having sensitivity to an external magnetic field such as a magnetoresistive effect element is provided, it is affected by the external magnetic field. Since the magnetoresistive element is composed of the same film type as that of the detection unit, the temperature characteristic of the element can be made the same and the magnetic sensor characteristic is stabilized.

  Since a highly sensitive TMR element is employed as the magnetoresistive effect element, it is possible to detect magnetism with a small amount of power consumption, thereby reducing the global environmental load.

  Magnetizing the pinned layer (fixing the magnetization direction) of the sensing element consisting of a magnetoresistive effect element by applying a magnetic field from the direction perpendicular to the substrate surface while heating the entire substrate, so the magnetization process is performed once. Can magnetize the detector.

  The present invention is mounted on a device using GPS, such as a car navigation system or a mobile phone device, and can be used for applications such as checking the current location in a place where radio waves from the GPS are blocked.

It is an example of the structure of the magnetic sensor which arrange | positioned the magnetoresistive effect element of a present Example by bridge circuit wiring, and is a figure which shows a schematic plane typically. It is the schematic sectional drawing which has arrange | positioned the magnetoresistive effect element on the slope in the II-II line cross section of FIG. 1A is a plan view of the magnetoresistive element structure of FIG. 1, and FIG. 1B is a sectional view taken along line IIIb-IIIb of FIG. It is a block diagram which shows a bridge connection. FIG. 3 is a diagram schematically illustrating a schematic plane in an example of a three-axis magnetic sensor configuration in which three sets of one-axis magnetic sensors are combined and arranged. It is an example of the structure of the magnetic sensor which arrange | positioned the magnetoresistive effect element of a present Example by bridge circuit wiring, and is a figure which shows a schematic plane typically. FIG. 7 is a schematic cross-sectional view in which magnetoresistive elements are arranged on a slope in a cross section taken along line VII-VII in FIG. It is a block diagram which shows a bridge connection. FIG. 3 is a diagram schematically illustrating a schematic plane in an example of a three-axis magnetic sensor configuration in which three sets of one-axis magnetic sensors are combined and arranged. It is a figure which shows typically the schematic plane of the magnetic sensor which shows a present Example, and is explanatory drawing for demonstrating regarding the fixed resistance part which has arrange | positioned the magnetic shielding film of a 1st Example. FIG. 11 is a cross-sectional view taken along the line XI-XI in FIG. 10, and is a cross-sectional view of a fixed resistance portion in which a magnetic shield film is arranged in the first embodiment (FIG. 3B). It is a part of flowchart which shows the manufacturing method of the magnetic sensor which concerns on this invention. It is the remainder of the flowchart which shows the manufacturing method of the magnetic sensor which concerns on this invention. It is an example of the structure of the magnetic sensor which arrange | positioned the magnetoresistive effect element of a present Example by bridge circuit wiring, and is a figure which shows a schematic plane typically. It is the schematic sectional drawing which has arrange | positioned the magnetoresistive effect element on the slope in the XV-XV sectional view of FIG. It is an example of the structure of the magnetic sensor which arrange | positioned the magnetoresistive effect element of a present Example by bridge circuit wiring, and is a figure which shows a schematic plane typically. It is the XVII-XVII line schematic cross section of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic sensor 2A, 2B Detection part 3A, 3B Fixed resistance part 4 Board | substrate 5A, 5B Groove 6 Wiring 7A, 7B, 7C Bonding pad

Claims (10)

A plurality of sensor bridge circuits in which a pair of detection units made of magnetoresistive elements and a pair of fixed resistors are bridge-connected are formed on the substrate, and the magnetization directions of the detection units cross each other in a three-dimensional direction. In the magnetic sensor formed in
The substrate has a plurality of inclined surfaces whose normal directions of inclination intersect three-dimensionally, and the pair of detection units in each sensor bridge circuit are arranged on the same inclined surface, respectively. Magnetic sensor. There are first to third sensor bridge circuits in which a pair of detection units each including a magnetoresistive element on a substrate and a pair of fixed resistors having a constant resistance value without being affected by an external magnetic field are bridge-connected. In the magnetic sensor formed and formed so that the magnetization directions of the detection units in the first to third sensor bridge circuits intersect each other in a three-dimensional direction,
The substrate has a plurality of inclined surfaces in which the normal direction of the inclination intersects three-dimensionally, and the detection unit in the first to third sensor bridge circuits has an inclined surface in which the normal direction of the inclination intersects three-dimensionally. A magnetic sensor characterized in that each of the pair of detection units disposed on the same sensor bridge circuit is disposed on an inclined surface having the same normal direction of the inclined surface. A plurality of sensor bridge circuits in which a pair of detection units made of magnetoresistive elements and a pair of fixed resistors are bridge-connected are formed on the substrate, and the magnetization directions of the detection units cross each other in a three-dimensional direction. In the magnetic sensor formed in
It consists of a (100) single crystal silicon wafer and has an inclined surface in which the (111) direction crystal orientation plane that forms an inclination angle of about 55 ° with the substrate surface is an inclined surface and the normal direction of the inclined surface intersects three-dimensionally. And a pair of detection part in each sensor bridge circuit is each distribute | arranged on the same inclined surface, The magnetic sensor characterized by the above-mentioned. First to third sensor bridge circuits are formed in which a pair of detection units made of magnetoresistive elements and a pair of fixed resistors having a constant resistance value without being affected by an external magnetic field are bridge-connected on a substrate. In the magnetic sensor formed so that the magnetization directions of the detection units in the first to third sensor bridge circuits intersect with each other in a three-dimensional direction,
It consists of a (100) single crystal silicon wafer and has an inclined surface in which the (111) direction crystal orientation plane that forms an inclination angle of about 55 ° with the substrate surface is an inclined surface and the normal direction of the inclined surface intersects three-dimensionally. The detection units in the first to third sensor bridge circuits are respectively arranged on the inclined surfaces in which the normal directions of the inclinations intersect three-dimensionally, and the pair of detection units in the same sensor bridge circuit are the methods of the inclined surfaces. A magnetic sensor characterized by being arranged on a slope having the same line direction.   The fixed resistor is composed of a magnetoresistive effect element composed of the same film type as that of the detection unit, and is covered with a magnetic shield member via an insulating member that can obtain electrical insulation. The magnetic sensor according to any one of 1 to 4.   6. The magnetic sensor according to claim 1, wherein the fixed resistor is disposed on an inclined surface formed on the substrate.   The magnetic sensor according to claim 1, wherein the magnetoresistive effect element is a tunnel magnetoresistive effect element. Preparing a substrate;
Forming a plurality of inclined surfaces in which the normal direction of the inclination intersects the substrate three-dimensionally;
Arranging a pair of detection units in each sensor bridge circuit on the same inclined surface,
And a step of magnetizing a pinned layer of a detection unit made of a magnetoresistive element by applying a magnetic field from a direction perpendicular to the substrate surface while heating the entire substrate. Manufacturing method.   9. The method according to claim 8, further comprising: a step of using the fixed resistor as a magnetoresistive effect element made of the same film type as that of the detection unit, and covering with a magnetic shield member through an insulating member capable of obtaining electrical insulation. The manufacturing method of the magnetic sensor of description.   10. The method of manufacturing a magnetic sensor according to claim 8, wherein a tunnel magnetoresistive effect element is used as the magnetoresistive effect element.

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