JPH05298625A - Magneto-resistance effect element and its manufacture - Google Patents

Abstract

PURPOSE:To solve such a problem that a protection film is broken owing to a dieing and water enters from the broken part to cause a pattern to corrode and have an open circuit and such a problem that man-hours as many as dieing processes are required as to the magneto-resistance effect element which uses a glazed alumina substrate as its base and has a pattern of a fine (<=tens of mum) thin film. CONSTITUTION:An electrode 4 is formed on the alumina substrate 1, glass glaze 2 is formed on one surface of the alumina substrate 1 to less than element size in contact with the electrode 4, and a metallic thin film 3 is formed on the glass glaze 2 so that the film is connected to the electrode 4. Consequently, the open circuit due to corrosion can be eleminated and the dieing process can also be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive effect element using a glaze alumina substrate as an underlayer and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in order to improve detection sensitivity and accuracy, magnetoresistive effect elements are required to have a structure (element surface is smooth) which can be placed parallel to and closest to the object to be detected. Has been. In addition, in terms of device characteristics, the smoothness of the surface of the base substrate is required. For this reason, the magnetoresistive element is provided on the alumina substrate with a glaze made of high melting point glass containing silicon oxide, aluminum oxide, barium oxide, calcium oxide, etc. as a main component and having excellent surface smoothness, and at the corners of the substrate. An electrode connecting the front and back sides in contact with, and a detection pattern made of a ferromagnetic material connected to the electrode is provided on the glaze, and an inorganic protective film that covers the detection pattern and an organic protective film that covers the entire surface are provided, The lead wire was taken out from the back electrode. And the manufacturing method was as follows. First, silicon oxide, aluminum oxide, barium oxide, and calcium oxide are the main components on all surfaces except the through holes and lands of the alumina substrate, which has V grooves on the back surface at each chip size interval and through holes at the intersections of the V grooves. The glass paste described below was screen-printed and fired at 1200 ° C. Furthermore, after silver-palladium paste for electrodes is screen-printed on the land and through holes and baked at 850 ° C., a ferromagnetic material such as permalloy is vapor-deposited on the entire glaze side, and resist coating, exposure, development, etching, and resist stripping are performed. After that, a magneto-sensitive pattern having a target shape in contact with the electrode was obtained. Then, for example, after depositing SiO on the pattern,
First, only the glaze is diced so that each through hole is divided into four, then the substrate is bent along the V groove to obtain a rectangular plate-shaped element, and then the lead wire is soldered to the back surface electrode. It was

[0003]

However, in the above structure, since the through hole pitch of the substrate has a large tolerance, the protective film is cut and destroyed in a dicing method after the positioning is performed at a certain point. There was something. The element in which the protective film is cut and destroyed has a problem that the pattern is corroded and broken when water enters through a gap formed between the glaze and the protective film.

In order to solve the above problems, the present invention provides a magnetoresistive effect element having excellent environment resistance and a method for manufacturing the same.

[0005]

In order to achieve the above object, a magnetoresistive effect element of the present invention comprises an electrode formed on an alumina substrate and an element which is smaller than the element size on one side of alumina and is in contact with the electrode. With the formed glass glaze,
The glass glaze is characterized by having a pattern portion formed of a metal thin film having a predetermined shape formed so as to be connected to the electrode.

[0006]

According to this function, since the glaze is formed independently in each element, dicing is not necessary at the time of division. Therefore, since the protective film is not cut and broken, the reliability of the element is improved and the number of steps can be reduced by reducing the dicing process.

[0007]

【Example】

(Embodiment 1) A magnetoresistive effect element according to an embodiment of the present invention and a method for manufacturing the same will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a magnetoresistive effect element according to an embodiment of the present invention, FIG. 2 is a top view of the magnetoresistive effect element according to an embodiment of the present invention, and FIG. Note that FIG. 7 is a top view of a conventional magnetoresistive effect element for comparison with FIG. 6. In FIG. 1, 1 is a quadrangular alumina substrate, 2 is a glass glaze containing lead oxide, boron oxide, and silicon oxide as main components, 3 is a metal thin film, 4
Are electrodes, and 5 and 6 are protective films.

The magnetoresistive element according to one embodiment of the present invention is
There are electrodes 4 having a silver: palladium ratio of 13:87 for connecting the front and back at four corners of the alumina substrate 1, and 50 wt% of lead oxide, 5 wt% of boron oxide and 35 w of silicon oxide.
A glass glaze 2 containing t% and aluminum oxide 5 wt% as main components is in contact with the electrode 4 so as to be adjacent thereto, and covers a part of the alumina substrate 1. A metal thin film 3 having a thickness of 0.1 μm and a width of 10 μm, which is made of permalloy, is formed on the electrode in contact with the electrode, and the permalloy film and the glass glaze 2 serve as a protective film 5. This is a structure in which SiO is covered and the entire surface is covered with an epoxy resin which is also the protective film 6. The surface roughness of the glaze 2 is 0.20 μmRa or less.

With respect to the magnetoresistive effect element of the present invention and the conventional magnetoresistive effect element thus constructed, a reliability test (PCT (121 ° C., 2 atm, 100% humidity) 100
H, constant temperature and humidity (60 ° C, 95% humidity) 2000H,
Constant temperature and humidity load (60 ° C, 95%, 5V applied) 1000
H) was performed. The number of defects in each test is shown in (Table 1). As is apparent from the table, the conventional product had a disconnection defect, but the magnetoresistive element of the present invention did not.

From the above, it can be seen that the magnetoresistive effect element of the present invention is more excellent in environmental resistance reliability than conventional products.

[0011]

[Table 1] (Embodiment 2) Hereinafter, a method of manufacturing a magnetoresistive effect element according to Embodiment 1 of the present invention will be described with reference to the drawings. Figure 3
5 is a process drawing of a magnetoresistive effect element in one embodiment of the present invention, FIG. 4 is a process drawing of a conventional magnetoresistive effect element, FIG.
FIG. 5A is a top view of the alumina white substrate, and FIG. 5B is a back view of the alumina white substrate.

First, in the through hole 8 and the land forming portion of the alumina substrate 1 (see FIG. 5) having V grooves 7 on the back surface of the substrate at element size intervals and having through holes 8 at the intersections of the V grooves 7, for example, After screen-printing a conductor paste having a ratio of palladium to silver of 13:87 and firing at 900 ° C., for example, 50 wt% of lead oxide, 5 wt% of boron oxide, 35 wt% of silicon oxide and 5 wt% of aluminum oxide are contained in the inorganic content. The glass paste as the main component was screen-printed in the range shown in FIG. 6 and fired at 800 ° C.

This substrate was placed in a vacuum vapor deposition machine, evacuated to a predetermined vacuum degree, permalloy was vapor-deposited to a thickness of 0.1 μm, and resist coating, exposure, development, etching,
The resist was stripped off to obtain a magnetic sensing part having a pattern shape in which a stripe having a width of 10 μm was folded back. After that, this substrate was placed in a vacuum vapor deposition machine, and after evacuation to a predetermined degree of vacuum, Si was placed in a range slightly larger than glaze 2 (see FIG. 6).
O was vapor deposited. The substrate was taken out, and an epoxy resin was screen-printed on the surface of the substrate and cured at 150 ° C. afterwards,
The substrate was divided along the V groove to obtain 255 elements as shown in FIGS. 1 and 2, and a lead wire was soldered to the back surface electrode.

As is clear from the comparison with the conventional example (see FIGS. 3 and 4), the dicing process can be eliminated by the method of manufacturing the magnetoresistive effect element according to the present embodiment.

As described above, the manufacturing method of the present invention is effective in reducing the man-hours (simplifying the man-hours).

[0016]

As described above, according to the present invention, the glass glaze containing lead oxide, boron oxide, silicon oxide, and aluminum oxide, which are excellent in surface roughness, as the main components is formed in a range smaller than the element size. It is possible to eliminate the dicing process, eliminate destruction of the protective film, and obtain a magnetoresistive effect element having high environmental resistance reliability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a magnetoresistive effect element according to this embodiment.

FIG. 2 is a top view of the magnetoresistive effect element according to the present embodiment.

FIG. 3 is a manufacturing process diagram of the magnetoresistive effect element according to the present embodiment.

FIG. 4 is a manufacturing process diagram of a conventional magnetoresistive effect element.

5 (a) and 5 (b) are a top view and a back view of an alumina white substrate used for manufacturing the magnetoresistive effect element of the present invention.

FIG. 6 is a top view showing a formation position of a glaze of the magnetoresistive effect element according to the present embodiment.

FIG. 7 is a top view showing a formation position of a glaze of a conventional magnetoresistive effect element.

[Explanation of symbols]

 1 Alumina substrate 2 Glass glaze 3 Metal thin film 4 Electrode

Claims (3)

[Claims] 1. An alumina substrate, an electrode formed on the alumina substrate, a glass glaze which is smaller than the element size and is in contact with the electrode on one surface of alumina, and the electrode on the glass glaze. A magnetoresistive effect element having a pattern portion formed of a metal thin film having a predetermined shape, which is formed so as to be connected. 2. A glass glaze having a surface roughness of 0.20 μm.
The magnetoresistive effect element according to claim 1, wherein the magnetoresistive effect element is Ra or less. 3. A step of screen-printing a conductor paste for forming electrodes including the through holes on an alumina substrate having through holes provided at size intervals corresponding to the elements and then firing, and the element on the surface of the alumina substrate. A step of screen-printing and firing a glass paste so as to be smaller than the element size and in contact with the electrodes, and a pattern part made of a metal thin film of a predetermined shape so as to be connected to the electrodes on the surface of the alumina substrate. A method of manufacturing a magnetoresistive effect element, comprising: a forming step; and a step of dividing the alumina substrate into individual elements.