JPH04367289A - Hall element - Google Patents

Abstract

PURPOSE:To flatten a Hall element as well as to lessen the gap between the Hall element and a magnetic material to be detected. CONSTITUTION:Through holes 11 to penetrate a substrate 10 in the directions of the surface and back of the substrate 10 are for in the substrate 10, conductive through electrodes 12 are respectively provided in these holes 11, a thin film-shaped magnetism-sensing film 13 having a Hall effect is formed on the surface of the substrate 10, electrode patterns 14 to connect this film 13 with the electrodes 12 and a protective film 15 covering these patterns 14 and the film 13 are formed and the electrodes 12 are made to expose to the rear of the substrate 10 and are used as electrode parts 16. As the thin film-shaped film 13, the patterns 14 and the film 15 are formed on the surface of the substrate 10, connections using bonding wires become unnecessary, a small-sized and flat Hall element is obtained and moreover, a gap between the element and a material to be detected can be made small and a large Hall output voltage is obtained. Moreover, the element can be directly mounted on a printed- wiring board or the like by the electrode parts led to the rear of the substrate and a packaging space can be lessened.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Hall element used for detecting magnetism such as the position of a rotor magnetic pole of a brushless motor.

0002

[Prior Art] In order to detect the magnetic pole position of a rotor magnet of a brushless motor, this type of Hall element is arranged in close proximity to each other, and changes in the magnetic pole are outputted from the Hall element as a detection signal. There is. Figures 5 and 6
indicates a conventional Hall element H, which is made of magnetic material such as ferrite,
Alternatively, on the surface of a substrate 1 made of a non-magnetic material such as ceramic, a magnetically sensitive layer 3 made of indium antimony (InSb) or the like is formed in the center via an insulating layer 2 by vapor deposition or the like, and this magnetically sensitive layer 3 and The device electrodes 5 are connected to bonding electrodes 4 for input or output provided at the four corners of the front surface of the substrate 1 . At least on the magnetically sensitive surface 3,
A protective film 6 is coated. Each of the bonding electrodes 4 is connected to one end of a bonding wire 7 made of gold or the like in order to connect to a lead frame (not shown), for example.

0003

[Problems to be Solved by the Invention] When using the above-mentioned conventional Hall element in a brushless motor, in recent years brushless motors have become shorter and shorter in the axial direction and have become flattened, and it has become necessary to flatten the Hall element itself. However, the bonding wire 7 is attached to the bonding electrode 4 formed on the surface of the substrate.
Since one end is connected and connected to an external component such as a lead frame through a detour so as to be separated from the substrate 1, there is a problem that the height dimension becomes large and it is difficult to flatten it. Furthermore, since the bonding wire 7 is located on the same surface as the magnetically sensitive surface 3, the gap with the rotor magnet becomes large, which inevitably causes the problem that the Hall output voltage from the Hall element becomes small.

The present invention was made to solve these problems, and the output of the magnetic sensing section having a Hall effect on the front surface of the substrate is transmitted to the electrode section on the back surface by means of a through electrode provided through the substrate. It is an object of the present invention to provide a Hall element that can flatten the Hall element and reduce the gap with a magnetically detected object by guiding the magnetic field.

[0005]

[Means for Solving the Problems] The present invention forms a through hole that penetrates a substrate in the front and back directions, provides a conductive through electrode in the through hole, and forms a thin film having a Hall effect on the surface of the substrate. A magnetically sensitive film having a shape, an electrode pattern connecting the magnetically sensitive film and the through electrode, and a protective film covering the electrode pattern and the magnetically sensitive film are formed, and the through electrode is formed on the back surface of the substrate. is characterized in that it is exposed to serve as an electrode part.

[0006]

[Operation] The Hall output voltage of the thin magnetically sensitive film having the Hall effect formed on the surface of the substrate is guided to the electrode portion on the back surface of the substrate via the through electrode in the through hole formed in the substrate. Only a thin magnetically sensitive film, an electrode pattern, and a protective film are formed on the surface of the substrate, and there is no need for connection with bonding wires, which makes it possible to flatten the substrate and improve the connection with the object to be detected. The gap can be made smaller and a larger Hall output voltage can be obtained. In addition, it can be mounted directly on a printed wiring board etc. using the electrodes guided to the back side of the board.
The mounting space is smaller.

[0007]

Embodiments Hereinafter, embodiments of the Hall element according to the present invention will be described with reference to FIGS. 1 to 4. In FIG. 1, the substrate 10 is preferably made of crystallized glass,
A through hole 11 penetrating in the front and back direction is provided near the four corners. A conductive through electrode 12 filled with fine copper powder is provided in the through hole 11, and the upper and lower end surfaces of the through electrode 12 are exposed so as to be flush with the front and back surfaces of the substrate 10. A thin magnetically sensitive film 13 made of, for example, indium antimony, indium arsenic, gallium arsenide, or the like having a Hall effect is formed on the surface of the substrate 10, and further connects the magnetically sensitive film 13 and the through electrode 12. An electrode pattern 14 is formed, and these magnetically sensitive films 13 and electrode pattern 1
A protective film 15 covering 4 is formed. On the other hand, an electrode portion 1 is provided on the end surface of the through electrode 12 exposed on the back surface of the substrate 10.
Further, solder bumps 17 are formed on the surface of the electrode portion 16 for connection to a pattern of an external wiring board (not shown) or the like.

Next, an example of a method for manufacturing such a Hall element will be explained. First, through-holes 11 provided near the four corners of the substrate 10 in the front and back directions are filled with finely powdered copper, which is made by crushing copper into minute particles, and then fired at a predetermined temperature at the same time as the substrate 10. Then, a through electrode 12 as shown in FIG. 2 is formed. At this time, when crystallized glass is used as the substrate 10, the firing temperature is almost the same as that of fine powder copper, and furthermore, in order to cause the crystallized glass to shrink, the fired fine powder copper is compressed in the through hole 11 and the substrate 10 is heated. It is possible to improve the adhesion with. Since the through electrode 12 may protrude from the substrate 10 after firing, the substrate 10 should be shaped so that the surface is flat.
Polish the front and back sides.

Next, in order to improve the ohmic contact with the magnetically sensitive film 13 and the electrode pattern 14 that will be formed in the next step, a metal material such as copper or gold is formed by sputtering, and then the four electrodes are A pattern 14 is formed. Furthermore, a magnetically sensitive film 13 made of indium antimony or the like is formed by vapor deposition to a thickness of 0.5 to 2 μm at the center of the electrode pattern 14 and patterned. As a result, as shown in FIG.
Connected via 4. After that, silicon oxide (SiO2) was used to protect the magnetically sensitive film 13 and the electrode pattern 14.
A protective film 15 is formed by vapor deposition or sputtering. Further, in order to improve the reliability of the Hall element, a protective coating section 18 made of a resin such as epoxy resin with a thickness of 10 to 30 .mu.m is provided to improve moisture resistance and mechanical strength at the same time.

On the other hand, as the electrode portion 16 of the through electrode 12 exposed on the back surface of the substrate 10, an electrode pad 16a is formed by screen printing a conductive paste having conductivity.
Furthermore, plating or solder is printed on the surface of the electrode pad 16a, and solder bumps 17 are formed by solder reflow, thereby completing the Hall element according to the present invention.

FIG. 4 shows a modified embodiment of the present invention, in which the substrate 1
0, a through-hole substrate was used in which photosensitive glass or perforated ceramic was used, and a conductive paste 19 was printed in the through-holes 20 on this substrate and then fired at a predetermined temperature. Note that the structure is the same as that of FIG. 1 described above except for the structure of the substrate 10.

The present invention is not limited to the above-mentioned embodiments, and the through electrode 12 is made of conductive paste material such as silver/palladium paste or copper paste in addition to finely powdered copper in the through hole 11. Alternatively, the material may be filled inside the container and fired. Further, the protective film may be formed of only an inorganic film such as silicon oxide without using a resin. In addition, the present invention can be implemented, such as by placing a magnetic amplification chip made of soft ferrite on the protective film located on the magnetically sensitive film 13 to guide the detected magnetic flux to the magnetically sensitive film 13 to increase the sensitivity of the Hall element itself. Various modifications can be made without departing from the spirit of the invention.

[0013]

Effects of the Invention As is clear from the above description, the Hall element of the present invention has a conductive through electrode in a through hole that penetrates a substrate in the front and back directions, and has a Hall effect on the surface of the substrate. A thin magnetically sensitive film and an electrode pattern are formed, and a through electrode is exposed on the back side of the substrate to serve as the electrode part, so there is no need to connect it with a bonding wire.
It has the advantage of being able to obtain a small and flat Hall element, and also being inexpensive because it does not require a lead frame or lead wire. Furthermore, the gap with the magnetically detected object can be reduced, and a large Hall output voltage can be obtained. Furthermore, since the electrode portion is led to the back surface of the substrate, it can be directly mounted on a printed wiring board or the like, which has the advantage of reducing the mounting space.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of a Hall element according to the present invention.

FIG. 2 is a perspective view showing a substrate in the Hall element as described above.

FIG. 3 is a perspective view showing a state in which a magnetically sensitive film and an electrode pattern of the Hall element are formed.

FIG. 4 is a perspective view showing another embodiment according to the present invention.

FIG. 5 is a plan view showing a conventional Hall element.

FIG. 6 is a sectional view showing the Hall element shown above.

[Explanation of symbols]

10　Substrate 11 Through hole 12 Through electrode 13 Magnetically sensitive film 14 Conductive pattern 15 Protective film 16 Electrode part

Claims (1)

[Claims] 1. A through hole passing through the substrate from front to back is formed, a conductive through electrode is provided in the through hole, and a thin magnetically sensitive film having a Hall effect is formed on the surface of the substrate. An electrode pattern connecting the magnetically sensitive film and the through electrode, and a protective film covering the electrode pattern and the magnetically sensitive film are formed, and the through electrode is exposed on the back surface of the substrate to serve as an electrode part. A Hall element characterized by: