JPH03200384A - Magnetic sensor - Google Patents

Abstract

PURPOSE:To flatten a sensor surface, and to use a glass board by forming a recess at least one side surface of the board to form a step on the board, using the higher stepped part of the board as a sensor surface, and connecting an outer lead to a reinforcing electrode on the recessed side of the lower stepped part. CONSTITUTION:A recess is formed at least on one side surface of a glass board 1 by etching to form a step 2 on the board 1, an insulating film 3 is formed on the board formed with the step 2, and a magnetic film sensor pattern 4 for forming a magnetoresistance element is formed on the sensor surface of the upper stepped part of the board 1. A terminal of the magnetic film for forming a conductive part is formed to the lower stepped recess though the step 2, the conductive part is superposed on the lower stepped recess from the terminal of the upper stepped part of the pattern 4 to form a reinforcing electrode 5, and an outer lead terminal 7 is electrically connected to the electrode 5 via a connecting electrode 6. Thus, the sensor surface is flattened, and the glass board can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic sensor using a magnetoresistive element in a detection section.

[Conventional technology]

2. Description of the Related Art Magnetic sensors that use magnetoresistive elements as magneto-sensitive elements are known, and are widely used in rotary encoders, motor rotation detection, and the like.

Conventionally, this type of magnetic sensor has, as shown in FIGS. 3(a) and 3(b), a magnetic resistance element 22 constituting a magnetic detection section, a base 21 to which the magnetic resistance element 22 is fixed, The structure includes a conductive terminal 26 to which a magnetoresistive element 22 is connected, and - for boat fishing, a base 21 made of an insulator such as glass
A magnetoresistive element 22 is provided on one side, a conductive terminal 26 is drawn out from the same side as this, and the conductive terminal 26 and the magnetoresistive element 22 are connected with solder 25, and then the surface is coated with a protective film 23, and then the conductive terminal 26 is pulled out from the same side. The terminal 26 and the magnetoresistive element 22 are soldered together in a structure in which the soldered portion is protected by coating with a terminal paint 24.

By the way, in the magnetic sensor having the structure shown in FIG.

Magnetoresistive element 22 and conductive terminal 26 that constitute a magnetic detection section
are on the same base surface, and the terminal paint portion 24 that protects the terminal portion 26 and the connection portion protrudes beyond the magnetoresistive element 22. For this reason, as shown in FIG. 4, when detecting the magnetism of a magnetic drum (or FG magnet, etc.) 31 whose circumferential surface is alternately magnetized with NS poles,
The protrusions of the terminal portion 26 and the terminal paint portion 24 must be provided at positions offset from the surface of the magnetic drum 31;
The base cannot be made small. ■ When adjusting the detection gap, the protrusion becomes an obstacle, so it takes time and effort, for example, to provide a step on the magnetic drum side. ■ Preventing misalignment of the magnetic drum 31 in the direction of the rotation axis 30. There were problems such as the need to take measures.

Therefore, in order to solve this problem, Fig. 5(a) is used.

As shown in (b), a magnetic detection section 44 is provided on one surface of an alumina base 41 having notches at least at four corners, and a magnetic detection section 44 is provided on one side of the alumina base 41, which has notches at least at four corners. A magnetic sensor has been proposed in which the detection part 44 and the terminal 47 on the back side of the base are electrically connected (Japanese Patent Application Laid-Open No. 63-34986).
.

The base 41 of this magnetic sensor is obtained by dividing a substrate having a large number of through holes.

Now, in the magnetic sensor having the structure shown in FIG. 5, since the terminal 47 is connected to the conductive part 45 on the back side of the base, the front side of the base can be flattened, and the detection gap can be easily adjusted. The magnetic sensor can also be easily miniaturized.

[Problem to be solved by the invention]

By the way, in the magnetic sensor having the structure shown in FIG.
In order to flatten the sensor surface, a notch hole is provided in the base using the through-hole method, but the thickness of the substrate for magnetic sensors is generally 5 mm to prevent substrate damage during processing.
Since a thickness of 00 to 1000 μm is used, it is technically difficult to form through holes. In particular, in the case of commonly used glass substrates that are inexpensive and have good surface roughness, it is extremely difficult to form through holes because they are easily broken and are chemically stable.

For this reason, an alumina ceramic substrate is used as the substrate for through-hole formation, but since the surface roughness of the alumina ceramic substrate is poor, if the magnetoresistive element film is formed directly on the substrate surface, the impedance of the magnetoresistive element will vary. This results in problems of deterioration of device characteristics, such as an increase in magnetoresistance, a decrease in magnetoresistive effect, and an increase in Barkhuisen noise, as well as etching residue. Therefore, when using an alumina ceramic substrate, it is necessary to polish the surface and cover the surface with glass in order to improve the surface roughness and eliminate etching residue on the magnetoresistive element film. Manufacturing costs are high. Further, it is necessary to provide a conductive part by firing a conductive material such as Ag-PD in the notch, which further increases costs.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a magnetic sensor that realizes flattening of the sensor surface and allows the use of a glass substrate.

[Means to solve the problem]

In order to achieve the above object, the magnetic sensor according to the present invention includes:
A step is formed in the substrate surface by recessing at least one surface of the glass substrate, and a magnetoresistive element is formed using the upper side of the substrate surface where the step is formed as a sensor surface, and a terminal of the magnetoresistive element is formed. A conductive part is provided from the part to the concave surface side of the lower stage, and an external lead terminal is provided on the side surface of the board, and the conductive part and the external lead terminal are connected via a connecting electrode on the concave machined surface side of the lower stage. It is characterized by being connected.

Further, the magnetic sensor is characterized in that the step is set by recess machining so that the amount of protrusion of the connection portion between the external lead terminal and the connection electrode is 50 μm or less from the sensor surface.

[For production]

In the magnetic sensor according to the present invention, at least one surface of the glass substrate is recessed to form a step in the substrate surface, and the upper side of the step higher than the substrate surface is used as the sensor surface, and the external lead and the conductive part are connected to each other. By making the connection on the concave surface side at the bottom of the step, the sensor surface can be easily flattened, and since the protruding portion of the connection part protrudes less than 50 μm from the sensor surface, it is suitable for magnetic rotors, etc. The detection gap with respect to the detection object side can be optimally adjusted, and the magnetic sensor can also be easily miniaturized.

〔Example〕

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a side cross-sectional view of a magnetic sensor showing an embodiment of the present invention, in which reference numeral 1 constitutes a glass substrate, numeral 2 constitutes a stepped portion, numeral 3 constitutes an insulating film, and numeral 4 constitutes a magnetoresistive element. In the magnetic film sensor pattern, reference numeral 5 is a reinforcing electrode, reference numeral 6 is a connection electrode, and reference numeral 7 is an external lead terminal.

In FIG. 1, in the present invention, at least one side of the glass substrate 1 is etched to form a recessed surface using a photolithography technique, so that two steps can be formed on the same substrate surface.
form. Then, an insulating film 3 is formed on the substrate surface on which the step 2 is formed.

This insulating film 3 is formed to prevent impedance drift due to ions such as Na'' ions contained in the glass substrate.The insulating film 3 may include a silicon nitride film, an alumina film, or an insulating film thereof. A multilayer film with an insulating film as the uppermost layer is formed by vapor deposition, sputtering, chemical vapor deposition, etc. However, alkali-free glass (aminosilicate glass), which has been used as a glass substrate for the electronic industry in recent years, is used. ), the above insulating film may not be provided.

A magnetic film sensor pattern 4 made of Ni alloy constituting the magnetoresistive element is formed on the sensor surface on the upper side of the substrate surface,
After deposition by vapor deposition or sputtering, a desired sensor pattern is formed by photolithography. The thickness of the magnetic film is - - used by 500 to 2000 people for boat fishing.

Further, in the example shown in FIG. 1, the terminal portion of the magnetic film is formed across the stepped portion 2 to the concave surface side below the step, and constitutes a conductive portion.

A reinforcing electrode 5 is placed over the conductive part from the terminal part on the crotch of the magnetic film sensor pattern 4 to the concave surface side at the bottom of the step.
This reinforcing electrode 5 is formed to prevent wire breakage at the stepped portion 2 since the conductive portion made of the magnetic film is thin. Further, the reinforcing electrode 5 is made of Ni, Cr, Co, M
The electrode structure is formed of a single layer or a multilayer structure of these materials. However, the slope of the stepped portion 2 is gentle, and the magnetic film sensor pattern 3
The reinforcing electrode 5 is not necessarily required if the external lead terminal 7 is electrically connected to the connecting electrode 6 at the etched recessed portion.

Electrical connection between the external lead terminal 7 and the reinforcing electrode 5 (or the conductive portion made of the magnetic film) is made via a connection electrode 6 made of conductive paste, cream solder, or a solder ball. At this time, it is preferable to set the step by recess machining so that the amount of protrusion of the overlapping part (connection part) of the external lead terminal 7 and the connection electrode 6 is 50 μm or less from the sensor surface on which the magnetic film sensor pattern 4 is formed. .

Although not shown in FIG. 1, the surface of the substrate after the magnetic film sensor pattern 4 and electrode 6 are formed is covered with an insulating protective film.

Now, in the magnetic sensor having the above configuration, at least one surface of the glass substrate 1 is recessed to form a step 2 in the substrate surface, and the upper side of the step higher than the substrate surface is used as the sensor surface, and By connecting the external lead 7 and the reinforcing electrode 5 constituting the conductive part on the concave surface side at the bottom of the step,
The sensor surface can be easily flattened, and the protrusion of the connection part is set to be 50 μm or less from the sensor surface, making it possible to optimally adjust the detection gap with the sensing object such as the magnetic rotor. Furthermore, the magnetic sensor can be easily miniaturized.

Next, FIG. 2 is a side sectional view of a magnetic sensor showing another embodiment of the present invention, in which numeral 8 is a glass substrate, numeral 9 is a stepped portion, numeral 10 is an insulating film, and numeral 11 is a magnetic sensor. In the magnetic film sensor pattern constituting the resistance element, reference numeral 12 is a reinforcing electrode, reference numeral 13 is a connection electrode, and reference numeral 14 is an external lead terminal.

In the embodiment shown in FIG. 2, the magnetic film sensor pattern 1
1 is an example in which the sensor is provided only on the sensor surface of the crotch, and the conductive part is composed of only the reinforcing electrode 12.

That is, when the reinforcing electrode 12 is provided, the terminal portion of the magnetic film sensor pattern 11 only needs to be electrically connected to the reinforcing electrode.
This is because there is no need to extend the first terminal portion. It is sufficient that the reinforcing electrode 12 is not disconnected at the stepped portion 9, is electrically connected to the magnetic film sensor pattern 11, and is electrically connected to the external lead 14 via the connecting electrode 13. Further, the material and structure of the reinforcing electrode are the same as those shown in FIG.

Now, in the magnetic sensor having the configuration shown in FIG. 1 or 2, the reason why the glass substrates 1 and 8 are used is that the glass substrates are suitable for forming a magnetoresistive element using a magnetic thin film as a magnetic detection part. This is because it has sufficient surface roughness, is inexpensive, and is an IIA edge substrate.

By the way, when trying to realize a similar configuration using silicon (SL), a semiconductor widely used in ICs, etc., the external lead terminals or connection electrodes come into contact with the side surface of the substrate, so an insulating film must be formed on the side surface of the substrate. There is a need. However, since the insulating film can only be formed on the side surface of the substrate after separating the elements by dicing or the like, mass productivity becomes extremely poor. For this reason, bridge wiring or the like must be used to prevent the external lead terminals or connection electrodes from coming into contact with the side surface of the substrate, which is not a good idea as it becomes an obstacle to miniaturization and causes an increase in cost.

(Effects of the Invention) As described above, according to the present invention, at least one surface of the glass substrate is recessed to form a step within the substrate surface, and the upper side of the step higher than the substrate surface is used as the sensor surface. ,and,
By making the connection between the external lead and the reinforcing electrode that constitutes the conductive part on the concave surface side at the bottom of the step, the sensor surface can be easily flattened, and the protruding part of the connection part is located 5.5 degrees above the sensor surface.
Since it is set to be 0 μm or less, it is possible to mount the sensor by optimally adjusting the detection gap with respect to the sensing object such as the magnetic rotor.

Furthermore, according to the present invention, since the protruding part of the connection part is set to be 50 μm or less from the sensor surface, the size of the magnetic sensor can also be made smaller than the thickness of the magnetic rotor, etc., resulting in miniaturization. It also has the advantage that high-density mounting on a control board in a motor, etc. is easily possible.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a magnetic sensor showing one embodiment of the present invention, FIG. 2 is a side sectional view of a magnetic sensor showing another embodiment of the present invention, and FIGS. It is an explanatory diagram. 1.8...Glass substrate, 2,9...Step part,
3.10... Insulating film, 4.11... Magnetoresistive element film, 5.12... Reinforcement electrode, 6,13... Connection electrode, 7゜14... External lead terminal. IW54 Opening Z Diagram) Dimensions (4) Aki Proceedings Auxiliary Device (Spontaneous) 1゜Indication of the Case 1999 Patent Application No. 341970 2゜Name of the Invention Magnetic Sensor 3゜Relationship with the Case

Claims (1)

[Scope of Claims] 1. A step is formed in the substrate surface by recessing at least one surface of a glass substrate, and a magnetoresistive element is formed using the upper side of the substrate surface where the step is formed as a sensor surface. At the same time, a conductive portion is provided from the terminal portion of the magnetoresistive element to the lower concave surface side, and an external lead terminal is provided on the side surface of the substrate, and the conductive portion and the external lead are provided on the lower concave surface side. A magnetic sensor characterized in that it is connected to a terminal via a connecting electrode. 2. In the magnetic sensor according to claim 1, the amount of protrusion of the connection portion between the external lead terminal and the connection electrode is 5% from the sensor surface.
A magnetic sensor characterized in that a step is set by concave processing to be 0 μm or less.