JP2006308544A - Magnetic sensor and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic sensor, capable of measuring the magnetic field strength of three-axial directions sensing the magnetic field strength in the Z-axis direction by one or more magnetoresistive elements among three or more magnetoresistive elements mounted on one substrate. <P>SOLUTION: The four giant magnetoresistive elements 2, 3, 4 and 5 are mounted on a planar surface of the substrate 1. Among the four giant magnetoresistive elements, two giant magnetoresistive elements 2, 3 are an X axis sensor, remainder being two giant magnetoresistive elements 4, 5 are a Y axis sensor. A projection 6 is formed on the substrate 1, and on the elongated direction of the both side slopes of the projection 6, each of respective giant magnetoresistive elements 7, 8 is mounted. Since these giant magnetoresistive elements 7, 8 have detection axes parallel to the slope, that is, are directed in an upper slanting direction to the substrate 1, the magnetic field strength of three axes can be detected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic sensor in which a magnetoresistive element is mounted on a substrate, and in particular, includes a magnetoresistive element capable of measuring the strength of a magnetic field in a direction perpendicular to the surface of the magnetic sensor, and increases the strength of a magnetic field in a triaxial direction. It can be measured.

Three or more giant magnetoresistive elements, such as giant magnetoresistive elements, are placed on a single substrate, each with a different sensing axis, and the magnetic field strength in the three directions of the X, Y, and Z axes is measured. A magnetic sensor that can be used is proposed in Japanese Patent Application Laid-Open No. 2004-6752.
In this prior invention, two or more giant magnetoresistive elements each having a sensing axis in the X-axis direction and the Y-axis direction are disposed on the flat surface of the substrate, respectively, while a V-shaped groove is formed in the substrate. One or more giant magnetoresistive elements are disposed on the slope of the groove, and the magnitude of the magnetic field in the Z-axis direction is detected by the giant magnetoresistive element disposed on the slope.
JP 2004-6752 A

  The present invention relates to this prior invention, and the problem is that, as in the above-described prior invention, three or more magnetoresistive elements are mounted on one substrate, and one or more of the magnetoresistive elements are included. An object of the present invention is to obtain a magnetic sensor capable of sensing the strength of the magnetic field in the Z-axis direction and measuring the strength of the magnetic field in the three-axis direction.

To solve this problem,
The invention according to claim 1 is a magnetic sensor characterized in that a magnetoresistive element having sensitivity to a magnetic component in a direction perpendicular to the substrate surface is arranged on a slope of a peak portion formed on the substrate.
According to a second aspect of the present invention, a magnetoresistive element having sensitivity to a magnetic component in a direction perpendicular to one or more substrate surfaces is disposed on a slope of a ridge formed on the substrate, and two or more magnetoresistive elements are disposed on a flat surface of the substrate. The magnetic sensor is characterized in that a magnetoresistive element having sensitivity to a magnetic component in a direction parallel to the substrate surface is disposed.

  The invention according to claim 3 forms a convex step forming portion on the substrate, deposits an insulating film on the substrate including the step forming portion, and forms a convex portion corresponding to the step forming portion, Next, a method of manufacturing a magnetic sensor is characterized in that a slope is formed on the convex portion by plasma etching or microwave etching to form a peak, and then a magnetoresistive element is formed on the slope of the peak.

According to the invention of claim 4, a convex portion made of an insulating material is formed on a substrate, and then a slope is formed on the convex portion by plasma etching or microwave etching to form a peak portion. A method of manufacturing a magnetic sensor characterized by forming an element.
The invention according to claim 5 is the method of manufacturing a magnetic sensor according to claim 3 or 4, wherein the magnetoresistive element is formed on the flat surface of the substrate at the same time as the magnetoresistive element is formed on the slope of the peak portion. .

According to the present invention, a magnetoresistive element that can sense the strength of a magnetic field in the Z-axis direction can be provided on a substrate. For this reason, it can be set as a triaxial magnetic sensor by further providing the magnetoresistive element which has a sensing axis in a X-axis direction and a Y-axis direction on the flat surface of a board | substrate.
Moreover, these magnetoresistive elements can be simultaneously formed by the same thin film forming process.

The present invention will be described in detail below. In the following description, a giant magnetoresistive element is described as an example of the magnetoresistive element. However, in the present invention, other anisotropic magnetoresistive elements and magnetic tunnel effect elements can be similarly applied.
1 and 2 schematically show an example of the magnetic sensor of the present invention.
In these drawings, reference numeral 1 denotes a substrate. In this substrate 1, a semiconductor integrated circuit (not shown) to be a magnetic sensor drive circuit, a signal processing circuit, etc. is formed in advance on a semiconductor substrate such as silicon, and the surface thereof is insulated from silicon oxide, silicon nitride or the like. A film (not shown) is coated.

Four giant magnetoresistive elements 2, 3, 4, and 5 are provided on the flat surface of the surface of the substrate 1. Of the four giant magnetoresistive elements, the two giant magnetoresistive elements 2 and 3 have their sensing axes in the X-axis direction of the coordinate axes shown in FIG. Is provided.
Further, the remaining two giant magnetoresistive elements 4 and 5 have their sensing axes oriented in the Y-axis direction, and are provided side by side on the other peripheral portion of the substrate 1.

  Further, a peak portion 6 is formed on the surface of the substrate 1. The peak portion 6 has a trapezoidal cross-sectional shape and a bowl shape as a whole. The angle of the slope of the peak 6 is about 30 to 60 degrees, the width of the slope is about 5 to 7 μm, the width of the bottom of the peak 6 is 5 to 30 μm, and the length of the peak 5 is 50 to 200 μm. It has become.

Further, as shown in FIG. 2, one giant magnetoresistive element 7 and 8 is provided on each of the slopes in the longitudinal direction of the peak portion 6. These giant magnetoresistive elements 7 and 8 both have a sensing axis in a direction parallel to the inclined surface, that is, in a direction facing obliquely upward of the substrate 1. Therefore, these two giant magnetoresistive elements 7 and 8 are sensitive to the strength of the magnetic field in the Z-axis direction, and can measure the strength of the magnetic field in the Z-axis direction.
The arrows shown in FIGS. 1 and 2 indicate the direction of the sensing axis of each giant magnetoresistive element.

Therefore, this magnetic sensor can measure the strength of the magnetic field in the three-axis directions of the X axis, the Y axis, and the X axis.
Further, the surface of the substrate 1 provided with these six giant magnetoresistive elements 2 to 8 is covered with a protective film made of silicon oxide, silicon nitride or the like (not shown). It comes to be protected from.

  The six giant magnetoresistive elements 2 to 8 provided on the substrate 1 have a well-known configuration, and are composed of a plurality of band-shaped element bodies and bias magnets for connecting these element bodies. A pinned layer whose magnetization direction is fixed (pinned) in a predetermined direction and a free layer whose magnetization direction changes according to the direction of the external magnetic field are provided.

  Specifically, the element body is composed of a multilayer metal thin film laminate in which a conductive spacer layer, a pinned layer, and a capping layer are sequentially laminated on a free layer. For example, the free layer includes cobalt-zirconium- Three layers of a niobium amorphous magnetic layer, a nickel-cobalt magnetic layer, and a cobalt-iron magnetic layer are used, the spacer layer is made of copper, and the pinned layer is a cobalt-iron ferromagnetic layer. And a platinum-manganese diamagnetic layer are used, and the capping layer is made of tantalum.

  The giant magnetoresistive element having such a structure can be manufactured by a well-known technique such as sputtering, vapor deposition, ion plating, etc., and photolithography.

3 to 9 show an example of a method for forming the above-described peak portion 6 and a method for forming a giant magnetoresistive element on the slope thereof. In these drawings, reference numeral 11 denotes a substrate. The substrate 11 is the same as that shown in FIG. 1, and a first insulating film 12 is provided on the surface of the substrate 11.
The first insulating film 12 is made of silicon oxide, silicon nitride or the like and has a thickness of about 300 to 1500 nm.

  A convex step forming portion 13 made of a metal such as aluminum or aluminum alloy is provided at a predetermined position on the first insulating film 12. The step forming portion 13 has a rectangular parallelepiped shape, and has dimensions of about 1 to 3 μm in height, 2 to 15 μm in width, and about 50 to 200 μm in length.

  The step forming portion 13 forms a metal thin film made of aluminum, aluminum alloy or the like having a thickness of 1 to 3 μm on the second insulating film 12 by thin film forming means such as vapor deposition and sputtering, and the metal thin film is formed by photolithography. It can be formed by a method of removing unnecessary portions by etching.

  Next, as shown in FIG. 4, the second insulating film 14 is deposited on the first insulating film 12 including the step forming portion 13 to form the convex portion 15. The second insulating film 14 is made of silicon oxide formed by a CVD method such as a plasma CVD method or an ozone CVD method using silane, tetraethoxysilane or the like as a raw material compound, and has a thickness of about 3 to 5 μm. belongs to.

By forming the second insulating film 14, a convex portion 15 having a shape substantially similar to that of the step forming portion 13 is formed at a position corresponding to the step forming portion 13. The height of the projection 15 is about 3 to 5 μm, the width is 3 to 6 μm, and the length is about 50 to 200 μm.
When a plurality of the convex portions 15 are formed side by side on the substrate 1, the interval is preferably at least 5 μm.

  Next, plasma etching or microwave etching was performed on the substrate 11 in this state, and the upper corners of the protrusions 15 were tapered and the inclined surfaces 16 and 16 were provided as shown in FIG. Yamabe 17 is assumed.

  For the plasma etching, a parallel plate type plasma apparatus is used, and etching is performed in an atmosphere of argon, oxygen, or a mixed gas thereof by rotating the substrate 11 while tilting about 30 to 60 degrees with respect to the electrode plate. The processing conditions are, for example, an argon flow rate of 50 to 200 sccm, a pressure of 6.7 to 26.7 Pa, a high frequency output of 750 to 1500 W, and a frequency of 13.56 MHz.

  Microwave etching uses a device that introduces gas into the quartz tube and supplies microwaves from the waveguide into the quartz tube to generate plasma. Etching in an atmosphere of argon, oxygen, or a mixed gas of these. The processing conditions are, for example, an oxygen flow rate of 50 to 200 sccm, a pressure of 6.7 to 13.3 Pa, a microwave of 0.1 to 0.5 mA, a frequency of 2.45 GHz, and an RF power of 100 to 200 W (13.56 MHz). Is done.

  By this etching, the upper corner portion of the convex portion 15 made of the second insulating film 14 is scraped off, and the scraped silicon oxide adheres to the lower portion of the convex portion 15, and the slopes 16, 16 as shown in FIG. Will be formed. The inclination angle of the slope 16 is 30 to 60 degrees, preferably about 45 degrees, and the width of the inclined surface is about 5 to 7 μm.

  Subsequently, as shown in FIG. 6, a giant magnetoresistive element film 18 is formed on the second insulating film 14 including the slopes 16, 16 of the mountain portion 17, and a resist 19 is formed on the giant magnetoresistive element film 18. Apply. The giant magnetoresistive element film 18 is formed by sputtering, vapor deposition, ion plating, or the like, and the film configuration is the same as described above.

Next, as shown in FIG. 7, the resist 19 is exposed and developed, and portions other than the resist 19 on the giant magnetoresistive element film 18 formed on the slopes 16, 16 of the peak 17 are removed, and the peak 17 A part of the giant magnetoresistive element film 18 formed on the slopes 16, 16 is covered with a resist 19.
At this time, the thickness of the resist 19 at the end of the giant magnetoresistive film 18 closer to the summit (upper side of the slope 16), that is, the distance from the apex of the resist 19 to the end of the giant magnetoresistive film 18. However, the thickness of the resist 19 is adjusted so as to be 1.0 to 2.0 μm, preferably 1.5 μm.
Further, a part of the giant magnetoresistive element film 18 formed on the flat surface of the second insulating film 14 on the substrate 11 is similarly covered with the resist 19, and the giant magnetism for X-axis sensing is placed on the flat surface. It is preferable to form the resistance element and the Y-axis sensing giant magnetoresistive element at the same time.

Next, as shown in FIG. 8, after the remaining resist 19 is heated to change its shape, the portion of the giant magnetoresistive element film 18 not covered with the resist 19 is removed by milling or the like, Further, the resist 19 remaining on the giant magnetoresistive element film 18 is dissolved and removed with an organic solvent or the like.
As a result, as shown in FIG. 9, giant magnetoresistive elements 20, 20 are formed on the middle portions of the slopes 16, 16 of the mountain portion 17. In addition, as shown in FIG. 7, if the resist 19 is left on the flat surface of the second insulating film 14, the portions are used as the X-axis sensing giant magnetoresistive element and the Y-axis sensing giant magnetoresistive element. Can do.

FIG. 10 is a perspective view showing the giant magnetoresistive element 20 obtained as described above. The giant magnetoresistive element 20 formed on the middle part of the slope 17 of the mountain portion 17 has a shape in which the end portion in the longitudinal direction is rounded as shown in the figure. ,
Thereafter, a magnetic film is produced by forming a protective film made of silicon oxide, silicon nitride or the like thereon.

11 to 13 show another example of the method for forming the peak portion in the present invention.
First, as shown in FIG. 11, a third insulating film 21 made of silicon oxide is formed on the first insulating film 12 on the substrate 11. The third insulating film 21 is made of silicon oxide formed by a CVD method such as a plasma CVD method or an ozone CVD method using silane, tetraethoxysilane or the like as a raw material compound, and has a thickness of about 3 to 5 μm. belongs to.

  Thereafter, the third insulating film 21 is etched to form a convex portion 22 having the same shape as the convex portion 15 of the previous example, as shown in FIG. The height of the convex portion 22 is about 3 to 5 μm, the width is 3 to 25 μm, and the length is about 50 to 200 μm. When a plurality of the convex portions 22 are formed on the substrate 1, the interval is set to at least 5 μm as in the previous example.

Subsequently, plasma etching or microwave etching is performed on the convex portion 22 in the same manner as in the previous example, and the upper corner portion of the convex portion 22 is taper-etched as shown in FIG. Is processed into a ridge 23.
The method of forming a giant magnetoresistive element on the slope of the peak 23 is the same as the previous example.

  In the method of this example, it is not necessary to form the step forming portion 13 made of a metal such as aluminum or aluminum alloy, and to form the second insulating film 14 thereon, so that the process is shortened. In addition, since the second insulating film 14 does not exist on the flat surface of the substrate 11, there is an advantage that stress on the substrate 11 is reduced.

It is a schematic perspective view which shows an example of the magnetic sensor of this invention. It is a schematic sectional drawing which shows the principal part of an example of the magnetic sensor of this invention. It is a schematic sectional drawing which shows the process of an example of the manufacturing method of the magnetic sensor of this invention. It is a schematic sectional drawing which shows the process of an example of the manufacturing method of the magnetic sensor of this invention. It is a schematic sectional drawing which shows the process of an example of the manufacturing method of the magnetic sensor of this invention. It is a schematic sectional drawing which shows the process of an example of the manufacturing method of the magnetic sensor of this invention. It is a schematic sectional drawing which shows the process of an example of the manufacturing method of the magnetic sensor of this invention. It is a schematic sectional drawing which shows the process of an example of the manufacturing method of the magnetic sensor of this invention. It is a schematic sectional drawing which shows the process of an example of the manufacturing method of the magnetic sensor of this invention. It is the perspective view which looked at a partial cross section which shows the giant magnetoresistive element obtained by this invention. It is a schematic sectional drawing which shows the process of the other example of the manufacturing method of the magnetic sensor of this invention. It is a schematic sectional drawing which shows the process of the other example of the manufacturing method of the magnetic sensor of this invention. It is a schematic sectional drawing which shows the process of the other example of the manufacturing method of the magnetic sensor of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 ... Board | substrate 2, 3, 4, 5, 7, 8, 20 ... Giant magnetoresistive element, 6, 17, 22 ... Mountain part, 13 ... Level difference formation part, 15, 22 ... convex part

Claims (5)

  A magnetic sensor, wherein a magnetoresistive element having sensitivity to a magnetic component in a direction perpendicular to a substrate surface is disposed on a slope of a mountain portion formed on a substrate.   A magnetoresistive element having sensitivity to a magnetic component in a direction perpendicular to one or more substrate surfaces is disposed on a slope of a peak formed on the substrate, and a magnetic component parallel to two or more substrate surfaces is disposed on a flat surface of the substrate. A magnetic sensor having a sensitive magnetoresistive element disposed therein.   A convex step forming portion is formed on the substrate, an insulating film is deposited on the substrate including the step forming portion, and a convex portion corresponding to the step forming portion is formed, and then this etching is performed by plasma etching or microwave etching. A method of manufacturing a magnetic sensor, comprising forming a slope by forming a slope on a convex portion and then forming a magnetoresistive element on the slope of the slope.   A convex portion made of an insulator is formed on a substrate, and then a slope is formed on the convex portion by plasma etching or microwave etching to form a peak, and then a magnetoresistive element is formed on the slope. Manufacturing method of magnetic sensor. 5. The method of manufacturing a magnetic sensor according to claim 3, wherein the magnetoresistive element is formed on the flat surface of the substrate simultaneously with forming the magnetoresistive element on the slope of the mountain portion.

Images