JPS5955082A - Magneto-resistance effect element - Google Patents

Abstract

PURPOSE:To enable to approach an element to a magnet by forming a thin ferromagnetic film on a film, and covering the film with it to package it, thereby enabling to inexpensively manufacture the element itself and reducing the thickness of the element. CONSTITUTION:A ferromagnetic material 6 such as permalloy is placed as a material for a magneto-resistance element in a vacuum container 5, and when an electron beam 7 is emitted thereto, the material 6 is molten to become ultrafine particles 8, which are flown. This is throttled in a suitable range by a shutter 9, and collided to a resin film 10 which is flexible and has relatively high heat resistant temperature, thereby forming a thin film of several hundreds to serveral thousands Angstrom thick. A detector 23 and rectangular pad 24 of folded pattern by thin ferromagnetic films are formed on the film 10 formed in a reduced thickness, a thin gold film 25 is formed on the pad 24, a film 26 is superposed on the pattern film, rolled by hot rolls, thereby obtaining a magneto-resistance element 31 which is completely packaged.

Description

[Detailed description of the invention] 1. The invention is thin so that it can be placed close to the magnet,
A magnetoresistive element that can be manufactured at low cost.

The purpose is to make suggestions. As shown in Figure 1, Kou's magnetoresistive element (hereinafter referred to as magnetoresistive element) consists of a ferromagnetic material on a glass substrate. Form a certificate! The Sunda magnetoresistive element is mounted on a non-magnetic metal lead frame (2), and electrically connected to the lead frame (2) by wire bonding using a thin gold or aluminum wire (3). After connecting, molding and sealing with a sealing resin such as Nixi, Nri, Fun, etc. to form the badge (4), there is no solder on the battery.

It is then manufactured by cutting, dropping, and dropping individual parts from the lead frame. In this way, just the encapsulation process excluding the lead frame forming process (2) involves die bonding, wire bonding, molding, solder plating, cutting, and removing!・Requires a process 1. ,,The disadvantage was that the mast height was high. , also requires the thickness of the sealing resin, - Magnetoresistive element (1)
Since the distance from the detection part, that is, the thin film part, to the package surface is at least 1 or more, this
All water no. When placing it close to the attached magnet on the evening impeller to rotate the impeller, write, or use it as a sensor...
...The distance between the magnet and the detection part cannot be made small, which has the disadvantage that the detection and output sensitivity as a rotation sensor is reduced.

1. This invention solves the above-mentioned drawbacks and proposes a magnetoresistive element, in which ferromagnetic,
A thin film is formed and processed, and then a film is placed on top of it.

Next, the manufacturing method will be explained based on the drawings.

Figure 2 shows the process of forming a thin film.
, ferromagnetic materials (6), such as permaray, nickel, and cobalt alloys, which are materials for magnetoresistive elements;
Electronic heat (7) k bath heat 7y Tomura N (6) '
,,3. It melts and becomes fine powder (8) and flies off. This is narrowed down to an appropriate range using a gold shutter (9) and applied to FILNO-01, a flexible resin such as polyamide or polypropylene that has relatively high heat and humidity resistance, to form a thin film with a thickness of several hundred to several thousand amps. Film (10 is required for the magnetoresistive element'1.r8-
It has an rlJ of 7m and a positioning sprocket hole on one or both sides, and has an rlJ of 70~/4/min overall. One reel of this film is several tens of meters long (1
1), and then winding the film in the other direction 1.1-, +1/Q' while sequentially forming a thin film all over the film (lower surface in the figure). In order to raise the Wk of film 01 and keep the film temperature constant, apply a thin film on the back side of the film (the second side of the film in the figure) where the thin film is to be completely formed. As shown in FIG.
e After coating to a uniform thickness and pre-baking with hot air or infrared rays 051, exposed to light using a mask 0η and ultraviolet rasive 0 mark, and wound onto the right reel θ1). The rollers and sprockets act as a damper between the coating process, which is a continuous process, and the exposure process, which is an intermittent process, as well as positioning the exposure process.

Figure 3 shows the steps from development to drying 15.

The exposed film (]-o b) is developed in a developing tank (11), post-baked with hot air or infrared rays α9, etched in an etching tank (g), and then transferred to several water tanks C1.
) and cypress (a) containing resist remover.
The film (10c) is removed by a fan and dried with infrared rays aQ to form a film (10c) with a nog turn 'P; as a magnetoresistive element, which is wound onto a reel θ°C on the -· side.

Film with pattern formed (]-oc) f 5th
As shown in the figure. The part where the folded bumps made of the ferromagnetic thin film are formed on the 1- (- side) of the film 01 is a magnetoresistive element that changes resistance! 4-. It is a detection part @,
The rectangular part) ■ is a pad part for electrical connection with the outside. A gold layer of gold or the like is formed on the surface of this pad member so that it can be easily contacted with the outside. The method for forming the gold layer is as follows:
This can be carried out by the same steps as explained based on FIGS. 2 to 3 above.

A thin gold film @ fully formed film on the pad part (l Od
) is shown in Figure 4. Note that if indium half-111 is used in the half-11 coating described later, a thin gold film (
To) iff is unnecessary.

Figure 7 shows the same dimensions as the film (11) and the pad part @
A rectangular hole of the same size @ all pads (c) and a film (to) that was opened in the same position as the film (1 oa)
)k is shown. The film (1 oa) is for covering and sealing the film (1 oa).

Between the film (], Oa) and the film (e), a polyester film with a low heat-resistant temperature for adhesion may be used as an adhesive layer by sandwiching a piece of the same shape as the film (to), or an adhesive such as epoxy adhesive may be used. The agent may be applied to the entire adhesive surface of the film (c).

In the soil-laying process shown in Fig. 5, the film (E) is superimposed on the patterned surface of the film (1, Od), and the film (E) is bonded with heat using a heat roller (C), or it is bonded with other methods such as ultrasonic pressure bonding. Then, a packaged film (l Oe) is obtained.

In No. 9M, the film (loθ) is passed through a half tank (g) and sprayed onto the solder 04, leaving a hole (a) in the film (l Oe) and exposing the thin gold film (c). Half [■
Step 7 of layering the gold layer on the film (10t) which has been fully coated and ready for soldering connection is shown.

The thus obtained film (10f) is cut out to a size slightly larger than the entirety of the magnetic detection part (1) and pad part (c) to form the entire completed magnetoresistive element. Figure 70 (A)
, (B) shows a front view and a cross-sectional view of the magnetoresistive element 01) thus completed.

As an example of dimensions in Figure 1O, the detection part (C) is 5I
The line width of the folded part at the I11 angle is 70 to 20μ
m, the film thickness is 1000 A - 2000 A f, and the resistance value of the bottom part is several 7 OKQ to several hundred KO.

The window hole (a) of the connection pad is l wm ;■If it is, the element portion 9 M X ! ; wm, and around it the crimped edge of the film QO, (1) is /1111~2-
Since it is necessary, the overall size is 7. ! Becomes cod position.
If a film (1G, (1)) with a thickness of about 30-11.0 μm is used, the total thickness will be about 70mm.

Figure 1 shows an example in which the element of this invention is applied to rotation detection.
A magnetoresistive element Oυ is placed close to the top surface of the rotating magnet (A).
A current of 1 is applied from a constant current source. The resistance value of the element changes according to the rotation, and a fluctuating voltage e1 is obtained. A comparator (total) compares it with a voltage e2 that is centered between the voltage e1 output from the reference voltage source (2), and outputs a rectangular waveform voltage esk corresponding to the rotation. In the case of this circuit, if the resistance value change of the magnetoresistive element 6η due to a temperature change is larger than the resistance value change due to a change in the magnetic field, malfunction will occur, so a bridge circuit using 2 or 1 gold magnetoresistive element is usually used.

Figure 72 is an example of a circuit with 0 magnetoresistive elements and 1 magnetoresistive element.
The direction of the folded part indicates the direction with respect to each magnetoresistive element (3°C magnet (2). (b) is the reference voltage source,
(to) is a comparator.

Figure 73 shows a magnetoresistive element (
Figure 3 shows the pattern arrangement of

FIG. 1/1 is an example of a magnetoresistive element (b) having a total of 1 detection parts, 2 in each direction in 2 directions.

Figure 75 shows an example of a water meter that uses magnetic resistance elements.
2) or (b). The magnetoresistive element (7) or (b) is a printed circuit board (
2), the - side is soldered.

FIG. 7 is a cross-sectional view showing the mounting state on the board (toward). The copper element (g) on the board is soldered to <G11) with solder. This soldering is performed using an infrared furnace, ultrasonic waves, or flow soldering.

Because the impeller must be made lightweight due to the water meter's sensitivity requirements, large magnets cannot be used for the magnet. Therefore, the magnetic field required for the magnetoresistive element can only be obtained in a very limited range, and in order for the detection part (c) of the magnetoresistive element to fall within that range, it is better to make the package as thin as possible. Magnetoresistive element using the package of the invention)
or ) fulfills that requirement.

Designed and designed to use magnetoresistive elements in conventional packages
By using the element of the present invention, the water meter that was manufactured can be brought closer to the magnet, so the impeller (
Since the magnet (to) attached to (to) can be made smaller and lighter, it is possible to improve the sensitivity of the water meter and reduce the cost of the impeller. In addition, in a water meter, in order to detect the rotation direction of the impeller, two sets of magnetic resistance elements (to) or @Kumquats are installed with each set offset by about f30, and a comparator (to) is connected to each of them. The direction of rotation is detected using the fact that the output phase is shifted by about 30 degrees. At this time, in the conventional package (Fig. 1), when the elements are stacked, there are two
Since the distance from the magnet (2) varies by approximately m, the range of the magnetic field generated by the magnet (2) needs to be wide, and a large magnet is required. Moreover, even if two sets are arranged in a plane, a large magnetic field range is still required.

According to the device of the present invention, the above drawbacks can be overcome.

Figure 77 shows a magnetoresistive element (b) which has a total of t detection parts, one moss in two directions, and a magnetoresistive element (b) which has two detection parts in each direction, which is shifted by about 30 degrees, for a total of l detection parts. element(
6) is shown.

FIG. 1g shows a cross-sectional view in which the magnetoresistive elements (b) and (6) are mounted.

In this way, the two upper and lower magnetoresistive elements (a) and (6) can be mounted close to each other at a distance of about 70 m to 1 m. The flexibility of the film used in the device of the present invention also contributes to this. Therefore, the rotation direction can be detected without changing the size of the magnet (A).

Further, in the present invention, the film (LOD) and 0, on which the patterns of the magnetoresistive element (B) and (6) shown in FIG. 77 are formed after completing the steps shown in FIGS. 4. □
Wow -□1. B24. □Wa,□: Then, as shown in Figure 1, a magnetoresistive element (goods) in which the l-direction g element is integrated can be obtained.

In this case, the interval between the two upper and lower magnetic resistance detection parts (to) is 30
It can be formed in the order of ~aOμm.

In applications such as water meters, it is required that the power consumption be as low as possible because it is operated by batteries, and the resistance value of the magnetic resistance element? It has to be high. For this purpose, the thickness of the thin film is made as thin as possible, and the line width of the detection part (e) is made as narrow as possible, but there is a certain limit naturally, and the only way to do this is to increase the total line length. It is necessary to increase the total surface area of the resistive element. If the total length of the sides of the element were doubled, in the conventional device using silicon wafers or glass substrates, the amount removed from seven substrates of the same area would be 4.

On the other hand, in the present invention, even if the width of the film θ0 is doubled and produced, the equipment will hardly change, and the length direction will therefore be doubled, so the amount taken from the same equipment will be b,
It is advantageous in terms of cost compared to conventional ones.

As described above, according to the present invention, not only can the magnetoresistive element itself be manufactured at a lower cost, but also the element can be made thinner and the distance from the magnet can be closer than that of gold, making it possible to improve the quality of equipment that uses this element. It also has the effect of contributing to improved performance.

[Brief explanation of the drawing]

Figure 7 is a perspective view of a conventional magnetoresistive element, Figures 2 to 7
The figure is a diagram explaining the method for manufacturing the magnetoresistive element of the present invention.
Figures 70 (A) and (B) show an example of the magnetoresistive element (full-oil front view and cross-sectional view A), and Figure 70 (η/1) shows Shio's electrical circuit applied to detecting the full rotation of the magnetoresistive element. Figure 12 is another applied circuit, Figures 73 and 11 are front views showing examples of different patterns of magnetoresistive elements, Figure 1S is a vertical cross-sectional view of a water meter using magnetoresistive elements, and Figure 1B Figure 77 is an enlarged vertical cross-sectional view illustrating the mounting state of the element on the printed circuit board mTh in Figure 3'; Figure 77 is a front view showing two different examples of magnetoresistive elements for detecting the direction of rotation; Figure 1g' The figure is an enlarged vertical cross-sectional view of a full-oil film in which two elements of the present invention are mounted one on top of the other, and Figure 79 is a cross-sectional view of a further different mounting example. ...Detection part 0◇, (to) formed of ferromagnetic thin film
, CI'6. ■... Magnetoresistive element 08- JP-A-59-55082 (5)

Claims (1)

[Claims] Complete formation and processing of ferromagnetic thin film, 3.
A magnetoresistive element characterized in that it is packaged by covering it with a film.