JP2017063106A - Hall element and Hall sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the variation of off-set voltage of a Hall element.SOLUTION: A Hall element comprises: a rectangular semiconductor substrate; a magnetosensitive part, formed on one face of the semiconductor substrate, which is a mesa-shaped in cross sectional view and has a slant face on its outer edge; and an electrode parts, arranged diagonally at four corners on one face side of the semiconductor substrate, which are electrically connected to the magnetosensitive part. The magnetosensitive part has a rectangular main magnetosensitive part and is formed such that outer edge sides of the main magnetosensitive part may be parallel to the sides of the semiconductor substrate respectively facing the sides of the main magnetosensitive part in a plan view.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hall element and a hall sensor.

Conventionally, magnetic sensors have been applied to many magnetic sensor products such as current detection devices and position detection devices. As a typical example of a magnetic sensor, there is a Hall element using the Hall effect.
The Hall element generally has a magnetic sensing part, a current electrode pair for passing a current through the magnetic sensing part, and an output electrode pair for detecting Hall electromotive force, and is detected from the output electrode pair. The magnitude and direction of the magnetism applied to the magnetic sensing part are detected from the generated Hall electromotive force.

Patent Document 1 discloses a Hall element including a semi-insulating GaAs substrate, an N-type operation layer, an N + contact layer, an ohmic junction metal film, a bonding metal film, and an insulating film. .
Patent Document 2 discloses a Hall element having a shape in which four inner corner portions of a cross-shaped Hall element are chamfered obliquely rather than at a right angle.
Patent Document 3 discloses a silicon Hall element including a semiconductor substrate, a first N-type diffusion region, a second N-type diffusion region, and an STI region.

JP 60-175471 A JP-A-1-298354 JP 2012-204616 A

However, the conventional Hall element has insufficient measures against fluctuations in the offset voltage of the Hall element.
An object of the present invention is to provide a Hall element and a Hall sensor in which fluctuations in offset voltage are suppressed.

In order to solve the above-described problems, a Hall element of one embodiment of the present invention is formed on a rectangular semiconductor substrate and one surface of the semiconductor substrate, has a mesa shape in cross-sectional view, and has a slope on an outer edge portion. A magnetic sensing part, and electrode parts arranged at diagonally four corners on the one surface side of the semiconductor substrate and electrically connected to the magnetic sensing part, the magnetic sensing part having a rectangular shape And are arranged so that each side of the outer edge of the main magnetosensitive part is parallel to each side of the semiconductor substrate facing the sides of the main magnetosensitive part in plan view. It is characterized by that.
A hall sensor of one embodiment of the present invention includes the above-described hall element.

  According to one embodiment of the present invention, fluctuations in the offset voltage of the Hall element and the Hall sensor can be suppressed.

It is a top view for demonstrating the structure of the Hall element of the 1st Embodiment of this invention. It is sectional drawing for demonstrating the structure of the Hall element of the 1st Embodiment of this invention. It is a figure for demonstrating the structure of the Hall sensor of the 1st Embodiment of this invention. It is a schematic diagram which shows the wire bonding area | region in the Hall sensor of the 1st Embodiment of this invention. It is process sectional drawing for demonstrating the manufacturing process of the Hall element of the 1st Embodiment of this invention. It is a process top view for demonstrating the manufacturing process of the Hall sensor of the 1st Embodiment of this invention. It is process sectional drawing for demonstrating the manufacturing process of the Hall sensor of the 1st Embodiment of this invention. It is a top view for demonstrating the structure of the Hall element of the 2nd Embodiment of this invention. It is sectional drawing for demonstrating the structure of the Hall element of the 2nd Embodiment of this invention. It is a top view for demonstrating the structure of the Hall element of the 3rd Embodiment of this invention. It is sectional drawing for demonstrating the structure of the Hall element of the 3rd Embodiment of this invention. It is a top view for demonstrating the structure of the magnetic sensing part of the Hall element of the 3rd Embodiment of this invention. It is a top view for demonstrating the structure of the Hall element of the 4th Embodiment of this invention. It is sectional drawing for demonstrating the structure of the Hall element of the 4th Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described. Note that dimensions, materials, and other specific numerical values shown in the following embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified.

1. First Embodiment (1-1) Configuration (1-1-1) Configuration of Hall Element FIG. 1 is a plan view for explaining the configuration of a Hall element 100 according to the first embodiment.
2A and 2B are sectional views of the Hall element 100 shown in FIG. 1, and FIG. 2A shows an A1-A′1 section of the Hall element 100 shown in FIG. 2B is a cross-sectional view showing a B1-B′1 cross section of the Hall element 100 shown in FIG.

  As shown in FIGS. 1 and 2, the Hall element 100 of the first embodiment includes a compound semiconductor substrate (hereinafter referred to as a substrate) 10. In addition, the Hall element 100 according to the present embodiment is formed on the one surface (for example, the upper surface) 10a side of the substrate 10 and on the one surface side of the substrate 10 and is electrically connected to the magnetic sensor 20. First to fourth electrode portions 31 to 34 connected to each other. The first electrode portion 31 and the second electrode portion 32 are input electrodes of the Hall element 100, and the third electrode portion 33 and the fourth electrode portion 34 are output electrodes of the Hall element 100.

Hereinafter, each part of the Hall element 100 will be described in detail.
(substrate)
The substrate 10 is, for example, a GaAs substrate. The resistivity of the GaAs substrate is 1.0 × 10 ⁷ Ω · cm or more. The upper limit of the resistivity of the GaAs substrate is not particularly limited, but for example, it is 1.0 × 10 ⁹ Ω · cm or less. The substrate 10 may be formed of a material such as Si or InSb.
The substrate 10 is formed in a rectangular shape in plan view. The shape of the substrate 10 in plan view (hereinafter referred to as a planar shape) is, for example, a quadrangular shape, a rectangular shape, a rounded quadrangular shape, or a rounded rectangular shape. The board | substrate 10 has edge | side S1, S2, S3, S4 in the outer edge in planar view.

(Magnetic part)
The magnetic sensitive part 20 is a layer (layer having high conductivity) having a lower resistance than that of the substrate 10 formed on one surface (for example, the upper surface) side of the substrate 10. In the present embodiment, the magnetic sensing unit 20 functions as a main magnetic sensing unit. The magnetic sensitive part 20 is formed on the upper surface of the substrate 10 and has a mesa shape in a sectional view (hereinafter referred to as a sectional shape). The magnetic sensing unit 20 has a mesa shape in cross section, and thus has an inclined surface 20a (see FIG. 2) at the outer edge of the magnetic sensing unit 20 in plan view.
In the Hall element 100 of the present embodiment, the magnetic sensitive part 20 is formed in a rectangular shape in plan view. The planar shape of the magnetic sensitive unit 20 is, for example, a quadrangular shape, a rectangular shape, a rounded square shape, or a rounded rectangular shape. The magnetic sensitive unit 20 has sides s1, s2, s3, and s4 on the outer edge in plan view. The magnetic sensing part 20 is arranged so that the sides s1, s2, s3, s4 of the outer edge of the magnetic sensing part 20 are parallel to the sides S1, S2, S3, S4 of the substrate 10, respectively. In addition, in this embodiment, the parallel includes an angle shift due to manufacturing variation or the like.

This is due to the following reason.
In the Hall sensor in which the Hall element 100 which is a chip is sealed with a mold resin, the area of the Hall element 100 on the diagonal line of the substrate 10 is relatively strong due to the difference in thermal expansion coefficient between the Hall element 100 and the mold resin. Stress distribution occurs. When the stress distribution is generated in the substrate 10, the offset voltage Vu of the Hall element 100 is changed.
Further, in the Hall element 100 including the magnetic sensing portion 20 processed into the mesa shape on the substrate 10, the slope 20a formed on the side surface (outer edge in the top view) of the magnetic sensing portion 20 has a particularly piezoelectric effect crystallographically. The resistance is large and a strong resistance fluctuation is easily caused by the stress. Since the inclined surface 20a is provided in the diagonal region of the substrate 10, the influence of the fluctuation of the offset voltage Vu is further increased.

  As described above, in the Hall element 100 of the present embodiment, the magnetic sensing unit 20 has the sides S1, S2, s3, and s4 of the outer edge of the magnetic sensing unit 20 as seen in a plan view. They are arranged so as to be parallel to S4. As a result, many portions of the inclined surface 20a of the magnetic sensitive portion 20 are formed in regions that avoid the diagonal region of the substrate 10 where a strong stress distribution occurs. For this reason, the fluctuation | variation of the offset voltage Vu of the Hall element 100 is suppressed.

Moreover, it is preferable that the length of the side s1 of the magnetic sensing unit 20 is not less than ¼ of the side S1 of the substrate 10 that is opposed to the length. Similarly, the lengths of the sides s2, s3, and s4 of the magnetic sensing unit 20 are preferably ¼ or more of the opposite sides S2, S3, and S4 of the substrate 10, respectively. Thereby, element destruction due to electrostatic discharge (ESD) is less likely to occur. Moreover, the noise (N / S ratio) of the output signal of the Hall element 100 is reduced by increasing the area of the magnetic sensing unit 20. More preferably, it is 1/3 or more, and more preferably half or more.
Further, the lengths of the sides s1, s2, s3, and s4 of the magnetic sensing unit 20 are ¼ or more of the sides S1, S2, S3, and S4 of the substrate 10, respectively. Of s1, s2, s3, and s4, the portion provided at a position further away from the diagonal region of the substrate 10 increases. Therefore, fluctuations in the offset voltage Vu of the Hall element 100 are further suppressed.

Areas near the corners c1 to c4 (hereinafter referred to as corners C1 to C4) of the magnetic sensitive part 20 are respectively covered with electrode parts (first to fourth electrode parts 31 to 34). It is preferable. In the present embodiment, the corner c <b> 1 of the magnetic sensing unit 20 is provided below the first electrode unit 31. In addition, the corners c2 to c4 of the magnetic sensing unit 20 are provided below the second to fourth electrode portions 32 to 34, respectively.
Thereby, a partial region of the magnetic sensitive portion 20 is covered with electrodes (first to fourth electrode portions 31 to 34) that are plastically deformed flexibly by stress from the upper surface. Therefore, the magnetic sensitive part 20 is not easily affected by the stress from the upper surface of the Hall element 100, and the fluctuation of the offset voltage Vu of the Hall element 100 is suppressed.
Further, the corner portions C1 to C4 of the magnetic sensitive portion 20 are located in regions on the diagonal line of the substrate 10 where a relatively strong stress distribution is generated. The slope 20a of the magnetic sensitive part 20 that is easily affected by a relatively strong stress distribution is covered with the electrode in the diagonal region of the substrate 10, so that the fluctuation of the offset voltage Vu of the Hall element 100 is more effectively suppressed. The

As shown in FIG. 2, the magnetic sensitive part 20 is formed on the upper surface of the substrate 10. The magnetic sensitive part 20 includes a conductive layer 21 and a surface layer 22 formed on the conductive layer 21. The conductive layer 21 is a layer made of n-type GaAs formed on the substrate 10. The film thickness of the conductive layer 21 is not particularly limited, but is preferably 50 nm or more and 2000 nm or less, and more preferably 100 nm or more and 1000 nm or less from the viewpoint of manufacturability.
As the n-type impurity (that is, donor-type impurity) of n-type GaAs, a known one can be used, and for example, Si, Ge, Se, or the like can be used. The concentration of n-type impurities (effective carrier concentration) is not particularly limited, but the effective carrier concentration is 1.0 × 10 ¹⁵ [cm ⁻³ ] or more and 1.0 × 10 ¹⁷ from the viewpoint of the output and temperature characteristics of the Hall element. [Cm ⁻³ ] or less is preferable, and 1.0 × 10 ¹⁵ [cm ⁻³ ] or more and 1.0 × 10 ¹⁶ [cm ⁻³ ] or less is more preferable, and 1.0 × 10 ¹⁵ [cm ³ ] or less. More preferably, it is not less than cm ⁻³ ] and not more than 5.0 × 10 ¹⁵ [cm ⁻³ ]. If the effective carrier concentration is within the above range, it is preferable because the temperature dependency of the output is suppressed and the absolute value of the output can be easily obtained.

  As a method for forming the conductive layer 21, there is a method in which an impurity is ion-implanted into the substrate 10 to form an n-type GaAs layer near or inside the surface of the substrate 10. As another method for forming the conductive layer 21, GaAs while doping impurity ions on the substrate 10 by MBE (molecular beam epitaxy) method or MOCVD (Metal Organic Chemical Vapor Deposition) method is used. There is a method of epitaxially growing a thin film.

  The surface layer 22 is a layer formed on the conductive layer 21 and made of a high-resistance crystal such as a GaAs layer having lower conductivity than the conductive layer 21 or AlGaAs or AlAs. The film thickness of the surface layer 22 is preferably 150 nm or more, and more preferably 200 nm or more in order to realize the Hall element 100 in which variation in sheet resistance is suppressed. Moreover, the film thickness of the surface layer 22 is preferably 800 nm or less, more preferably 600 nm or less, from the viewpoint of manufacturability. Note that the surface layer may be omitted.

  The method for forming the surface layer 22 is not particularly limited, and can be formed, for example, by ion implantation, or epitaxial growth using MBE or MOCVD. As a method for obtaining GaAs having a conductivity lower than that of the conductive layer 21 like the surface layer 22, a method of setting an impurity concentration lower than that of the conductive layer 21, a method of not intentionally doping impurities, and the like can be mentioned. Further, in order to directly ohmic-connect the conductive layer 21 and the first to fourth electrode portions 31 to 34, a part of the surface layer 22 may be etched to be thinned or removed.

It is preferable that the inclined surface 20 a formed at the outer edge portion of the magnetic sensitive part 20 has a shape that is nearly perpendicular to the substrate 10.
In the inclined surface 20a of the magnetic sensitive part 20 formed in the mesa shape, a carrier trap source due to an oxide or a defect exists at the interface between the conductive layer 21 and the insulating film 40. This carrier trap source causes the electrical conductivity of the Hall element 100 to change randomly in time and cause noise in the output signal of the Hall element 100. When the thickness of the magnetic sensing part 20 is constant, the area of the conductor layer 12b exposed from the slope 20a of the magnetic sensing part 20 becomes smaller as the angle of the slope 20a of the magnetic sensing part 20 becomes closer to the vertical, and noise is generated. The abundance of the carrier trap source as a source is reduced. For this reason, the noise of the output signal of the Hall element 100 is improved as the inclined surface 20a of the magnetically sensitive portion 20 has a shape closer to the perpendicular to the substrate 10.
The magnetic sensitive part 20 is preferably formed of GaAs from the viewpoint of temperature characteristics. However, the present embodiment is not limited to the configuration in which the magnetically sensitive portion 20 is formed using GaAs as a material, and for example, a compound semiconductor such as InSb or InAs can also be used.

(Electrode part)
The first to fourth electrode portions 31 to 34 are arranged at diagonally four corners on one surface (for example, the upper surface) side of the substrate 10 and are electrically connected to the magnetic sensing portion 20. As shown in FIG. 1, the first electrode part 31 and the second electrode part 32 face each other in the first direction D1. Further, the third electrode portion 33 and the fourth electrode portion 34 face each other in a second direction D2 that intersects (for example, is orthogonal to) the first direction D1 in plan view. Each of the first to fourth electrode portions 31 to 34 extends from the corner portion of the magnetic sensitive portion 20 to the central portion of the magnetic sensitive portion 20, and a part of the rectangular shape is removed in plan view. (For example, a pentagonal shape). The 1st-4th electrode parts 31-34 are formed in the shape which exposes the area | region of the center part of a magnetic sensing part. In the present embodiment, the first electrode part 31, the second electrode part 32, the third electrode part 33, and the fourth electrode part 34 cover the corners c1 to c4 of the magnetic sensitive part 20, respectively. Formed in position.

As shown in FIG. 2, the first electrode portion 31 has a stacked structure of a first metal film 311 and a second metal film 312 that are made of different materials. The region where the first metal film 311 and the second metal film 312 are stacked functions as a contact portion in the first electrode portion 31. The second electrode portion 32 has a stacked structure of a first metal film 321 and a second metal film 322 made of different materials. The region where the first metal film 321 and the second metal film 322 are stacked functions as a contact portion in the second electrode portion 32. In FIG. 2, cross sections of the first electrode portion 31 and the second electrode portion 32 are shown, but the third electrode portion 33 and the fourth electrode portion 34 (not shown in FIG. 2) are similarly laminated. It has a structure. In other words, the third electrode portion 32 has a laminated structure of the first metal film 331 and the second metal film 332 made of different materials (see FIG. 1). The region where the first metal film 331 and the second metal film 332 are stacked functions as a contact portion in the third electrode portion 33. The fourth electrode portion 34 has a stacked structure of a first metal film 341 and a second metal film 342 made of different materials. The region where the first metal film 341 and the second metal film 342 are stacked functions as a contact portion in the fourth electrode portion 34.
As the first metal films 311 and 321, for example, a structure in which AuGe / Ni / Au is laminated in order from the magnetic sensing unit 20 side can be used. The second metal films 312 and 322 may have a structure in which, for example, Ti / Au is laminated in order from the magnetic sensitive unit 20 side.
As shown in FIG. 2, an insulating film 40 is formed in a partial region between the first metal film 311 and the second metal film 312 of the first electrode portion 31. Similarly, an insulating film 40 is formed in a partial region between the first metal film 321 and the second metal film 322 of the second electrode portion 32. The insulating film 40 will be described later.

(Insulating film)
The insulating film 40 is formed so as to cover the surface and the side surface (slope 20a) of the magnetic sensing unit 20. The insulating film 40 includes a part of the region between the first metal film 311 and the second metal film 312 of the first electrode part 31 and the first metal film 321 and the second metal film of the second electrode part 32. Are formed in a part of the region between the metal films 322. The insulating film 40 is provided in order to improve the insulation between each electrode part (the 1st-4th electrode parts 31-34). As the insulating film 40, for example, a silicon nitride film (Si ₃ N ₄ film), a silicon oxide film (SiO ₂ film), an inorganic film (Al ₂ O ₃ ), a polyimide film, or a multilayer film in which a plurality of these films are stacked is used. be able to. Note that the insulating film 40 may be formed on the first metal films 311 and 321 as shown in FIG. 2 or may not be formed on the first metal film, but below the first metal film. It may be formed in a part.
In FIG. 1, the insulating film 40 is not shown for easy understanding of the structure of the Hall element 100. Further, a protective layer (not shown) may be formed on the magnetic sensitive part 20.

(Wire bonding area)
3A to 3C are a plan view and a cross-sectional view showing a wire bonding region in the Hall element 100, FIG. 3A is a plan view of the Hall element 100, and FIG. FIG. 3C is a cross-sectional view showing a C3-C′3 cross section of the Hall element 100 shown in FIG. 3A, and FIG. 3C is a cross-sectional view showing a D3-D′3 cross section of FIG.
As shown in FIGS. 3A to 3C, the first electrode portion 31 has a first wire bonding region 141 to which a thin metal wire is bonded on the upper surface side. The first metal film 311 constituting the first electrode portion 31 serves as a contact region where the first electrode portion 31 is in contact with the magnetic sensitive portion 20.

The second electrode portion 32 has a second wire bonding region 142 to which a fine metal wire is bonded on the upper surface side. The first metal film 321 constituting the second electrode portion 32 becomes a contact region where the second electrode portion 32 contacts the magnetic sensitive portion 20.
Further, the third electrode portion 33 has a third wire bonding region 143 to which a fine metal wire is bonded on the upper surface side. The first metal film 331 constituting the third electrode portion 33 becomes a contact region where the third electrode portion 33 is in contact with the magnetic sensitive portion 20.
Further, the fourth electrode portion 34 has a fourth wire bonding region 144 to which a fine metal wire is bonded on the upper surface side. The first metal film 341 constituting the fourth electrode portion 34 becomes a contact region where the fourth electrode portion 34 contacts the magnetic sensitive portion 20.

That is, in the present embodiment, the first to fourth electrode portions 31 to 34 are located outside the center positions of the first to fourth wire bonding regions 141 to 144 as viewed from the center of the magnetic sensing unit 20. Each contact region is located.
As described above, since the first electrode portion 31 and the second electrode portion 32 are input electrodes of the Hall element 100, the contact region between the first electrode portion 31 and the contact region of the second electrode portion 32 is the same. The path between them is a signal input path 145 in the Hall element 100. In addition, since the third electrode portion 33 and the fourth electrode portion 34 are output electrodes of the Hall element 100, a path between the contact region of the third electrode portion 33 and the contact region of the fourth electrode portion 34. Becomes the signal output path 146 in the Hall element 100.

(1-1-2) Configuration of Hall Sensor FIGS. 4A to 4D are diagrams illustrating a configuration example of the Hall sensor 600 according to the first embodiment of the present invention. FIG. 4A is a cross-sectional view showing an E4-E′4 cross section of the Hall sensor 600 shown in FIG. FIG. 4B is a plan view showing the configuration of the Hall sensor 600 according to the first embodiment of the present invention, in which the mold member is omitted to facilitate understanding of the configuration of the Hall sensor 600. ing. FIG. 4C is a bottom view showing the configuration of the Hall sensor 600 according to the first embodiment of the present invention. FIG. 4D is an external view showing the configuration of the Hall sensor 600 according to the first embodiment of the present invention.

4A to 4D, the Hall sensor 600 includes a Hall element 100, a lead terminal 520, first to fourth metal thin wires (conductive connection members) 531 to 534, A protective layer 540, a mold member 550, and an exterior plating layer 560 are provided. Further, the lead terminal 520 has first to fourth terminal portions 521 to 524.
The hall sensor 600 has, for example, an islandless structure and includes a plurality of terminal portions 521 to 524 for obtaining an electrical connection with the outside. As shown in FIG. 4B, the first to fourth terminal portions 521 to 524 are arranged around the Hall element 100.
For example, the first terminal portion 521 and the second terminal portion 522 are disposed so as to face each other with the Hall element 100 interposed therebetween, and the third terminal portion 523 and the fourth terminal portion 524 are formed as holes. They are arranged so as to face each other with the element 100 interposed therebetween. A straight line (virtual line) connecting the first terminal portion 521 and the second terminal portion 522 and a straight line (imaginary line) connecting the third terminal portion 523 and the fourth terminal portion 524 are viewed in plan view. Cross at. The lead terminal 520 (first to fourth terminal portions 521 to 524) is made of a metal such as copper (Cu), for example.

  The first to fourth thin metal wires 531 to 534 electrically connect the first to fourth electrode portions 31 to 34 included in the Hall element 100 and the first to fourth terminal portions 521 to 524, respectively. The conductor is made of, for example, gold (Au). As shown in FIG. 4B, the first thin metal wire 531 connects the first terminal portion 521 and the first electrode portion 31. The second thin metal wire 532 connects the second terminal portion 522 and the second electrode portion 32. The third fine metal wire 533 connects the third terminal portion 523 and the third electrode portion 33. The fourth thin metal wire 534 connects the fourth terminal portion 524 and the fourth electrode portion 34.

The protective layer 540 covers the surface of the substrate 10 opposite to the surface on which the first to fourth electrode portions 31 to 34 are provided. The protective layer 540 is not particularly limited as long as it can protect the substrate 10, and may include at least one of a conductor, an insulator, and a semiconductor. That is, the protective layer 540 may be a film made of any one of a conductor, an insulator, and a semiconductor, or may be a film including two or more of these. As the conductor, for example, a conductive resin such as silver paste can be considered. As the insulator, for example, an insulating paste containing epoxy thermosetting resin and silica (SiO ₂ ) as a filler, silicon nitride, silicon dioxide, and the like are conceivable. As the semiconductor, for example, bonding of a Si substrate or a Ge substrate can be considered. However, from the viewpoint of preventing leakage current, the protective layer 540 is preferably an insulator. The protective layer 540 may have a stacked structure.

  The mold member 550 molds the Hall element 100, the first to fourth terminal portions 521 to 524, and the first to fourth metal thin wires 531 to 534. In other words, the mold member 550 includes the Hall element 100, at least the surface side of the first to fourth terminal portions 521 to 524 (that is, the surface connected to the metal thin wire), and the first to fourth metals. The thin wires 531 to 534 are covered and protected (that is, resin-sealed). The mold member 550 is made of, for example, an epoxy thermosetting resin and can withstand high heat during reflow.

As shown in FIG. 4A and FIG. 4C, the first of the first to fourth terminal portions 521 to 524 is provided on the bottom surface side of the Hall sensor 600 (that is, the side mounted on the magnetic sensitive portion 20). At least a part of the surface (for example, the back surface) and at least a part of the first surface (for example, the back surface) of the GaAs substrate 10 are respectively exposed from the same surface (for example, the back surface) of the mold member 550. Here, the 1st surface of the 1st-4th terminal parts 521-524 is the 1st-4th metal thin wire 531-among the several surfaces which the 1st-4th terminal parts 521-524 have, respectively. This is the surface opposite to the surface connected to 534. The first surface of the GaAs substrate 10 is a surface opposite to the surface on which the first to fourth electrode portions 31 to 34 are provided among the plurality of surfaces of the GaAs substrate 10.
The exterior plating layer 560 is formed on the back surface of the terminal portions 521 to 524 exposed from the mold member 550. The exterior plating layer 560 is made of, for example, tin (Sn).

(1-1-3) Operation In the case of detecting magnetism (magnetic field) using the Hall sensor 600 described above, for example, the first terminal portion 522 is connected to the power supply potential (+) and the second terminal The part 522 is connected to the ground potential (GND), and a current flows from the first terminal part 521 to the second terminal part 522. Then, a potential difference V1−V2 (= Hall output voltage VH) between the third terminal portion 523 and the fourth terminal portion 524 is measured. The magnitude of the magnetic field is detected from the magnitude of the Hall output voltage VH, and the direction of the magnetic field is detected from the positive / negative of the Hall output voltage VH.
That is, the first terminal portion 521 is a power supply terminal portion that supplies a predetermined voltage to the Hall element 100. The second terminal portion 522 is a grounding terminal portion that supplies a ground potential to the Hall element 100. The third terminal portion 523 and the fourth terminal portion 524 are signal extraction terminal portions that extract the Hall electromotive force signal of the Hall element 100.

(1-2) Manufacturing Method (1-2-1) Manufacturing Method of Hall Element FIGS. 5A to 5F are cross-sectional views illustrating the manufacturing method of the Hall element 100 in the order of steps. As shown in FIG. 5A, first, a substrate 10 is prepared. The substrate 10 is, for example, a GaAs substrate 10. Next, donor-type impurities are ion-implanted into a position at a preset depth from the surface of the substrate 10. Examples of the donor-type impurity include Si, Sn, S, Se, Te, Ge, and C. Next, the substrate 10 is heated to activate the impurities. As a result, as shown in FIG. 5B, the conductive layer 21 having a lower resistance than the substrate 10 is formed in the substrate 10, and the surface layer 22 is formed on the conductive layer 21. Since the surface layer 22 has a lower impurity concentration than the conductive layer 21, it becomes a layer having a higher resistance than the conductive layer 21 (that is, a layer having low conductivity).

  In addition, you may perform the process of activating this impurity after the patterning process of the board | substrate 10 shown in FIG.5 (c). Moreover, you may perform by combining with the other heating process after the process shown in FIG.5 (c). The formation of the conductive layer 21 is not limited to ion implantation. For example, the conductive layer 21 may be formed by epitaxially growing GaAs containing impurities at a high concentration on the substrate 10 by MOCVD. In this case, following the formation of the conductive layer 21, GaAs containing impurities at a low concentration (or not containing impurities) is epitaxially grown to form a surface layer having a higher resistance than the conductive layer 21 on the conductive layer 21. 22 can be formed.

Next, as shown in FIG. 5C, the magnetic sensing part 20 having a mesa shape in cross-sectional view is formed. The magnetic sensitive part 20 is formed by patterning the substrate 10 using a photolithography technique and an etching technique.
Subsequently, as shown in FIG. 5D, a first metal film 311 is partially formed on the substrate 10 on which the magnetic sensitive portion 20 is formed. Here, the first metal film 311 is formed by stacking, for example, an AuGe film, a Ni film, and an Au film in this order. The first metal film 311 is formed by, for example, lift-off or mask vapor deposition. Lift-off is a method in which a metal film is deposited on a substrate on which a resist pattern is formed, and then the resist pattern is removed, so that the metal film is left only on a region not covered with the resist pattern on the substrate. Mask vapor deposition is a method of depositing a metal film only on a region immediately below the through hole of the substrate by depositing a metal film on the substrate through a plate in which the through hole is partially formed. After the first metal film 311 is formed, the substrate 10 is heated to alloy the interface between the substrate 10 and the first metal film 311.

  Next, as illustrated in FIG. 5E, the insulating film 40 is formed on the upper surface of the magnetic sensitive part 20 and the surface of the inclined surface 20 a exposed from below the first metal films 311 and 321 of the substrate 10. The insulating film 40 is formed so that a part of the first metal films 311 and 321 is exposed. The insulating film 40 is, for example, a silicon nitride film (SiN film). The insulating film 40 is formed on the entire upper surface of the substrate 10 by, for example, CVD (Chemical Vapor Deposition), and then the insulating film formed on the entire upper surface is patterned using a photolithography technique and an etching technique. Is formed. Note that the first metal films 311 and 321 may be formed after an insulating film is formed on the entire top surface of the substrate 10 and patterned to form the insulating film 40.

Next, as shown in FIG. 5F, second metal films 312 and 322 are partially formed on the substrate 10 on which the insulating film 40 is formed. Here, for example, a Ti film and an Au film are stacked in this order as the second metal films 312 and 322. The second metal films 312 and 322 are formed by, for example, lift-off or mask vapor deposition.
Thereafter, a protective film (not shown) or the like is formed on the substrate 10. Then, the substrate 10 is diced, and the substrate 10 is separated into pieces for each of the plurality of Hall elements 100. Through the above steps, the Hall element 100 shown in FIG. 1 and the like is completed.

(1-2-2) Manufacturing Method of Hall Sensor FIGS. 6A to 6E are process plan views showing a manufacturing method of the Hall sensor 600. FIG. FIG. 7A to FIG. 7D are process cross-sectional views illustrating a method for manufacturing the Hall sensor 600. In FIGS. 6A to 6E, the dicing blade width (ie, the kerf width) is not shown.
As shown in FIG. 6A, first, a lead frame 620 is prepared. The lead frame 620 is a substrate in which a plurality of lead terminals 520 shown in FIG. 6B are connected in the vertical direction and the horizontal direction in plan view.

  Next, as shown in FIG. 6B, for example, one surface of the heat-resistant film 580 is pasted on the back side of the lead frame 620 as a base material. For example, an insulating adhesive layer is applied to one surface of the heat resistant film 580. The adhesive layer is based on, for example, a silicone resin as a component. This adhesive layer makes it easy to attach the lead frame 620 to the heat resistant film 580. By sticking the heat resistant film 580 to the back surface side of the lead frame 620, the penetration region through which the lead frame 620 penetrates is closed with the heat resistant film 580 from the back surface side.

Next, as shown in FIG.6 (c), the hole which has the protective layer 540 in the area | region enclosed by the 1st-4th terminal parts 521-524 among the surfaces which have the adhesion layer of the heat resistant film 580. The element 100 is placed (that is, die bonding is performed). Here, die bonding is performed with the first surface of the substrate 10 opposed to the surface having the adhesive layer of the heat resistant film 580.
Next, as shown in FIG.6 (d), the end of the 1st-4th metal fine wires 531-534 is connected to the 1st-4th terminal parts 521-524, respectively, and the 1st-4th metal The other ends of the thin wires 531 to 534 are connected to the first to fourth electrode portions 31 to 34 of the Hall element 100, respectively (that is, wire bonding is performed). Then, as shown in FIG. 6E, a mold member 550 is formed (that is, resin molding is performed). This resin mold is performed using, for example, a transfer mold technique.

  For example, as shown in FIG. 7A, a mold die 590 including a lower die 591 and an upper die 592 is prepared, and a lead frame 620 after wire bonding is disposed in the cavity of the mold die 590. . Next, the mold member 550 heated and melted is injected into the cavity and the side of the heat-resistant film 580 having the adhesive layer (that is, the surface bonded to the lead frame 620) and filled. Thus, the Hall element 100, the lead frame 620, and the fine metal wires 531 to 534 are molded. That is, the Hall element 100, at least the surface side of the lead frame 620, and the fine metal wires 531 to 534 are covered and protected by the mold member 550. When the mold member 550 is further heated and cured, the mold member 550 is removed from the mold.

Next, as illustrated in FIG. 7B, the heat resistant film 580 is peeled from the mold member 550. As a result, the substrate 10 of the Hall element 100 is exposed from the mold member 550. Then, as shown in FIG. 7C, exterior plating is applied to the surface exposed from the mold member 550 of the lead frame 620 (at least the back surface exposed from the mold member 550 of each terminal portion 522-25). Then, the exterior plating layer 560 is formed.
Next, as shown in FIG. 7D, a dicing tape 593 is affixed to the upper surface of the mold member 550 (ie, the surface opposite to the surface having the exterior plating layer 560 of the Hall sensor 600). Then, for example, along the virtual two-dot chain line shown in FIG. 6E, the blade is moved relative to the lead frame 620 to cut the mold member 550 and the lead frame 620 (that is, dicing is performed). Do.) That is, the mold member 550 and the lead frame 620 are diced for each of the plurality of Hall elements 100 to be singulated. Through the above steps, the Hall sensor 600 shown in FIG. 4 is completed.

<Effect>
(1) In a Hall sensor in which a Hall element is sealed with mold resin, a relatively strong stress distribution is generated in a diagonal region of the Hall element substrate due to the difference in thermal expansion coefficient between the Hall element and the mold resin. As a result, the offset voltage Vu of the Hall element varies. In addition, the slope of the magnetosensitive part machined into a mesa shape has a particularly large piezoelectric effect crystallographically and tends to cause strong resistance fluctuations due to stress. Therefore, the slope of the magnetosensitive part is provided in the diagonal region of the substrate. As a result, the influence of the fluctuation of the offset voltage Vu becomes larger.

  On the other hand, in the first embodiment, the substrates s1, s2, s3, and s4 of the outer edge of the magnetic sensing unit 20 face the sides s1, s2, s3, and s4 of the magnetic sensing unit 20 in plan view. The ten sides S1, S2, S3, and S4 are arranged in parallel to each other. That is, the magnetic sensing unit 20 is arranged so that the side s1 of the magnetic sensing unit 20 is parallel to the side S1 of the substrate 10. Similarly, the magnetic sensing unit 20 is arranged so that the sides s2, s3, and s4 of the magnetic sensing unit 20 are parallel to the sides S2, S3, and S4 of the substrate 10, respectively. For this reason, according to the first embodiment, the slope 20a of the magnetically sensitive portion 20 that is likely to cause a strong resistance variation due to stress is located in a region away from the diagonal region of the substrate 10 and the offset voltage Vu of the Hall element 100. Fluctuations are suppressed.

(2) Moreover, in 1st Embodiment, the corner | angular parts C1-C4 of the four corners of the magnetic sensing part 20 are each covered with the 1st-4th electrode parts 31-34 which carry out plastic deformation flexibly with the stress from an upper surface. ing. For this reason, the magnetic sensing unit 20 is less susceptible to the stress from the upper surface of the Hall element 100, and the fluctuation of the offset voltage Vu of the Hall element 100 is suppressed. Moreover, since the slope 20a of the magnetic sensitive part 20 located in the area | region on the diagonal of the board | substrate 10 with which relatively strong stress distribution generate | occur | produces by this is covered with the 1st-4th electrode parts 31-34, it is more effective. Therefore, the fluctuation of the offset voltage Vu of the Hall element 100 is suppressed.

(3) In the first embodiment, the length of the side s1 of the magnetic sensing unit 20 is not less than 1/4 of the side S1 of the substrate 10, and the length of the sides s2, s3, s4 of the magnetic sensing unit 20 is The lengths are preferably ¼ or more of the sides S2, S3, S4 of the substrate 10, respectively. Thereby, element destruction due to electrostatic discharge (ESD) is less likely to occur. Further, the area of the magnetic sensing unit 20 in plan view is increased, and noise (N / S ratio) of the output signal of the Hall element 100 is reduced.
Moreover, the part provided in the position more distant from the area | region on the diagonal of the board | substrate 10 among edge | side s1, s2, s3, s4 of the magnetic sensing part 20 increases. Therefore, fluctuations in the offset voltage Vu of the Hall element 100 are further suppressed.

2. 2nd Embodiment In 1st Embodiment mentioned above, the case where the corners c1-c4 of the magnetic sensing part 20 were located in the lower part of the 1st-4th electrode parts 31-34 by planar view was demonstrated. However, the present invention is not limited to this.

  FIG. 8 is a plan view showing a configuration example of the Hall element 200 according to the second embodiment of the present invention. FIGS. 9A and 9B are cross-sectional views of the Hall element 200 shown in FIG. 8 taken along lines F8-F′8 and G8-G′8. As shown in FIGS. 8, 9A, and 9B, in the Hall element 200 according to the second embodiment, the corners c1 to c4 of the magnetic sensing unit 20 are first to fourth in plan view. It is located outside the electrode parts 31-34. That is, the outer periphery of each of the first electrode unit 31, the second electrode unit 32, the third electrode unit 33, and the fourth electrode unit 34 is a region surrounded by the outer periphery of the magnetic sensing unit 20 in plan view. Located inside.

Even in such a configuration, in the Hall element 200, the sides s1, s2, s3, and s4 of the outer edge of the magnetic sensing unit 20 are parallel to the sides S1, S2, S3, and S4 of the substrate 10 in plan view. It is arranged to be. Further, in the Hall element 200, the corners C1 to C4 at the four corners of the magnetic sensitive part 20 are respectively covered with first to fourth electrode parts 31 to 34 that are plastically deformed flexibly by stress from the upper surface. Therefore, the second embodiment has the same effects as the effects (1) to (2) of the first embodiment.
In the Hall element 200, when the lengths of the sides s1 to s4 of the magnetic sensing unit 20 are not less than ¼ of the sides S1 to S4 of the substrate 10, the second embodiment There exists an effect similar to the effect (3) of 1st Embodiment.

3. Third Embodiment In the first and second embodiments described above, the case where the planar shape of the magnetic sensitive unit 20 is rectangular has been described. However, the present invention is not limited to this.

  FIG. 10 is a plan view showing a configuration example of the Hall element 300 according to the third embodiment of the present invention. FIG. 11A and FIG. 11B are cross-sectional views of the Hall element 300 shown in FIG. 10 showing the H10-H′10 cross section and the J10-J′10 cross section. FIG. 12 is a plan view illustrating a configuration example of the magnetic sensing unit 20 according to the third embodiment.

  As shown in FIG. 10 to FIG. 12, the magnetic sensing part 20 of the Hall element 300 according to the third embodiment includes a main magnetic sensing part 120 having a rectangular planar shape and outer sides from the four corners of the main magnetic sensing part 120. 1st-4th extension part 121-124 extended to. The first extension part 121 and the second extension part 122 are respectively located on the extension line of the first diagonal line 126 of the substrate 10 in plan view. Further, the third extension portion 123 and the fourth extension portion 124 are respectively located on the extension lines of the second diagonal line 127 of the substrate 10. Corners C1 to C4 of the main magnetic sensing part 120 are covered with first to fourth electrode parts 31 to 34, respectively.

  The extending end portions of the first to fourth extending portions 121 to 124 are covered with first to fourth electrode portions 31 to 34, respectively. As shown in FIG. 10, the first extension portion 121 is electrically connected to the first electrode portion 31. The second extension part 122 is electrically connected to the second electrode part 32. The third extension part 123 is electrically connected to the third electrode part 33. The fourth extension portion 124 is electrically connected to the fourth electrode portion 34. In the extended end part of the 1st-4th extension parts 121-124 of the magnetic sensing part 20, it connects with the 1st-4th electrodes 31-34. In each extended end, the insulating film 40 has an opening, and the extended end and each electrode are connected through the opening.

As shown in FIG. 10, the main magnetic sensing unit 120 has sides s1, s2, s3, and s4 on the outer edge in plan view. Here, the side s <b> 1 of the main magnetic sensing part 120 is sandwiched between the first extension part 121 and the fourth extension part 124 which are two adjacent extension parts extending from the main magnetic sensing part 120. This part shall be indicated. Similarly, the side s2 of the main magnetic sensing portion 120 indicates a portion sandwiched between the adjacent fourth extension portion 124 and second extension portion 122 extending from the main magnetic sensitivity portion 120. To do. The side s3 of the main magnetic sensing portion 120 indicates a portion sandwiched between the adjacent second extending portion 122 and third extending portion 123 extending from the main magnetic sensitive portion 120. The side s4 of the main magnetic sensing portion 120 indicates a portion sandwiched between the adjacent third extending portion 123 and the first extending portion 121 extending from the main magnetic sensitive portion 120.
The length of the side s1 sandwiched between the adjacent first extension portion 121 and the fourth extension portion 124 extending from the main magnetic sensing portion 120 is ¼ or more of the side S1 of the substrate 10. It is preferable. It is preferable that the lengths of the sides s2 to s4 of the main magnetic sensing part 120 are ¼ or more of the sides S2 to S4 of the substrate 10, respectively.

Even in such a configuration, in the Hall element 300, the sides s1, s2, s3, and s4 of the magnetic sensing unit 20 are parallel to the sides S1, S2, S3, and S4 of the substrate 10 in plan view. Is arranged. Further, in the Hall element 300, the corners C1 to C4 at the four corners of the magnetic sensitive part 20 are respectively covered with first to fourth electrode parts 31 to 34 that are plastically deformed flexibly by stress from the upper surface. Therefore, the third embodiment has the same effects as the effects (1) to (2) of the first embodiment.
In the Hall element 200, when the lengths of the sides s1 to s4 of the magnetic sensing unit 20 are not less than 1/4 of the sides S1 to S4 of the substrate 10, the third embodiment There exists an effect similar to the effect (3) of 1st Embodiment.

4). Fourth Embodiment In the third embodiment described above, the first to fourth extending portions 121 to 124 are provided, and the corner portions C1 to C4 of the main magnetic sensitive portion 120 are the first to fourth electrode portions. The case where it was covered with 31-34 was demonstrated. However, the present invention is not limited to this.

FIG. 13 is a plan view showing a configuration example of the Hall element 400 according to the fourth embodiment of the present invention. FIGS. 14A and 14B are cross-sectional views of the Hall element 300 shown in FIG. 13 showing the K13-K′13 cross section and the L13-L′13 cross section.
As shown in FIG. 13, the magnetically sensitive part 20 of the Hall element 400 according to the fourth embodiment has a main magnetically sensitive part 120 having a rectangular planar shape and extends outward from four corners of the main magnetically sensitive part 120. The first to fourth extending portions 121 to 124 are provided. The first extension part 121 and the second extension part 122 are respectively located on the extension line of the first diagonal line 126 of the substrate 10 in plan view. Further, the third extension portion 123 and the fourth extension portion 124 are respectively located on the extension lines of the second diagonal line 127 of the substrate 10. The Hall element 400 according to the fourth embodiment is the same as that of the third embodiment in that corners C1 to C4 of the main magnetic sensing part 120 are not covered with the first to fourth electrode parts 31 to 34, respectively. Different from the Hall element 300.

The length of the side s1 sandwiched between the adjacent first extension portion 121 and the fourth extension portion 124 extending from the main magnetic sensing portion 120 is ¼ or more of the side S1 of the substrate 10. It is preferable. It is preferable that the lengths of the sides s2 to s4 of the main magnetic sensing part 120 are ¼ or more of the sides S2 to S4 of the substrate 10, respectively.
Even in such a configuration, in the Hall element 300, the sides s1, s2, s3, and s4 of the magnetic sensing unit 20 are parallel to the sides S1, S2, S3, and S4 of the substrate 10 in plan view. Is arranged. Therefore, the third embodiment has the same effect as the effect (1) of the first embodiment.
In the Hall element 200, when the lengths of the sides s1 to s4 of the magnetic sensing unit 20 are not less than 1/4 of the sides S1 to S4 of the substrate 10, the third embodiment There exists an effect similar to the effect (3) of 1st Embodiment.

  The scope of the present invention is not limited to the illustrated and described exemplary embodiments, but also includes all embodiments that provide equivalent effects to those intended by the present invention. Further, the scope of the invention is not limited to the combinations of features of the invention defined by the claims, but can be defined by any desired combination of specific features among all the disclosed features.

10 Substrate (compound semiconductor substrate)
10a Top surface 20 Magnetic sensing portion 20a Slope 21 Conductive layer 22 Surface layer 31 First electrode portion 32 Second electrode portion 33 Third electrode portion 34 Fourth electrode portion 40 Insulating film 100, 200, 300, 400 Hall element 120 Main magnetic sensing part 121 First extension part 122 Second extension part 123 Third extension part 124 Fourth extension part 126 First diagonal line 127 Second diagonal line 141 First wire bonding region 142 second wire bonding region 143 third wire bonding region 144 fourth wire bonding region 145 signal input path 146 signal output path 311, 321, 331, 341 first metal layer 312, 322, 332, 342 second Metal layer 520 Lead terminal 521 First terminal portion 522 Second terminal portion 523 Third terminal portion 524 Fourth terminal portion 531 1st metal wire 532 2nd metal wire 533 3rd metal wire 534 4th metal wire 540 Protective layer 550 Mold member 560 Exterior plating layer 580 Heat-resistant film 590 Mold die 591 Lower die 592 Upper die 593 Dicing tape 600 Hall sensor 620 Lead frame

Claims (7)

A rectangular semiconductor substrate;
A magnetic sensitive part formed on one surface of the semiconductor substrate and having a mesa shape in cross-sectional view and having an inclined surface at the outer edge,
Electrode portions disposed at diagonally four corners on the one surface side of the semiconductor substrate and electrically connected to the magnetically sensitive portion;
With
The magnetic sensing part has a rectangular main magnetic sensing part, and each side of the outer edge of the main magnetic sensing part is opposed to each side of the main magnetic sensing part in a plan view. Hall elements arranged so as to be parallel to each other. 2. The Hall element according to claim 1, wherein the magnetically sensitive part includes extended parts respectively extending from four corners of the rectangular main magnetically sensitive part. The length of the outer edge of the main magnetic sensitive part sandwiched between two adjacent extended parts extended from the main magnetic sensitive part is ¼ or more of the side of the semiconductor substrate facing the outer edge, respectively. The Hall element according to claim 2, which has a length of 4. The Hall element according to claim 2, wherein an extended end portion of the extended portion is covered with the electrode portion. In a cross-sectional view, further comprising an insulating film disposed between the magnetic sensing portion and the electrode portion,
The insulating film has an opening;
The Hall element according to claim 4, wherein the extended end portion of the magnetic sensing portion and the electrode portion are in contact with each other at the opening. 6. The Hall element according to claim 1, wherein corner portions of the main magnetically sensitive portion are respectively covered with the electrode portions. The hall element according to any one of claims 1 to 6,
A terminal section;
Fine metal wires connecting the electrode part and the terminal part,
A mold member for sealing at least a part of the Hall element, at least a part of the terminal part, and the fine metal wire;
Hall sensor equipped with.

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