JPS6249994B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetoelectric transducer having external leads and a method for manufacturing the same.

The present inventors have developed a magnetic transducer that can significantly reduce the manufacturing cost of a magnetoelectric transducer by significantly shortening the electrode formation process compared to conventional methods, that is, a magnetic transducer made of a compound semiconductor thin film, The present invention was arrived at as a result of intensive research in order to create a structure in which a magnetoelectric transducer having an electrode part whose part is made into a conductor has an external lead without impairing its characteristics.

The present invention has a lead connection electrode made of a compound semiconductor thin film, a part of which is made conductive by energy irradiation, and an external lead connected to the lead connection electrode made of a conductive resin. The present invention relates to a magnetoelectric transducer characterized in that the element is connected to the magnetoelectric transducer, and a method for manufacturing the same.

The compound semiconductor thin film used in the present invention may be any compound semiconductor thin film conventionally used as a magnetoelectric conversion element. In particular, compound semiconductors mainly composed of group and group elements are preferred. For example, InSb, InAs,
InP, InN, GaP, GaAs, GaSb, SaN, AlAs,
AlSb, AlP, AlN, BSb, BAs, BN, InSbGa,
InSbSn, InSb―NiSb, GaAsP, GaAlAs, InGaP
etc. are used.

The thin film referred to in the present invention is a semiconductor thin film normally used in magnetoelectric conversion elements, and generally,
The thickness ranges from about 0.1 to 100μ. Such semiconductor thin films include single crystals, polycrystals, eutectics, etc. made into thin films by methods such as polishing, thin films produced by methods such as vapor deposition, ion plating, and sputtering, liquid phase growth, and vapor phase growth. Any material such as a thin film produced by a method or the like may be used.

The electrode portion is formed by converting a portion of this compound semiconductor film (a portion to be used as an electrode) into a conductor. That is, by irradiating an appropriate amount of energy only to the electrode forming portion of the semiconductor thin film, the semiconductor becomes conductive and becomes an electrode that makes ohmic contact with the unirradiated portion of the semiconductor. Since the required irradiation energy differs depending on the semiconductor, it is best to obtain it by performing trial irradiation with different amounts of energy. Commonly available energy sources include Xe lamp light,
There are laser beams, electron beams, heat rays, etc. Note that specific energy irradiation conditions are shown in Examples, so please refer to them.

In the present invention, in addition to the electrodes for connecting the lead portions, other parts of the compound semiconductor thin film may be similarly electroded to provide a magnetoelectric transducer having short bars in order to increase the magnetic sensitivity.

The external lead used in the present invention may be a lead wire, a film-shaped or plate-shaped conductive lead, and it is sufficient that it is connected to the lead-portion connecting electrode through a conductive resin. In this way, by connecting external leads using conductive resin, it was possible for the first time to successfully provide external leads without impairing the properties of the compound semiconductor thin film whose electrode portion was made from a single piece.

The conductive resin used in the present invention is usually used in the form of a conductive resin paste, and either a commercially available one or a self-made conductive resin paste can be used if necessary. That is,
Fine powder of metals such as Ag, Ni, Pd, etc. are mixed into epoxy,
It is an electrically conductive resin paste that is imparted with electrical conductivity by being mixed with a binder such as polyamide-imide resin or acrylic resin.

The present invention will be explained below using the drawings. FIG. 1 is a cross-sectional view of one example of the magnetoelectric transducer of the present invention, in which a part of the compound semiconductor thin film 1 is made into a conductor and becomes the lead connection electrode 2, and the other part remains as the compound semiconductor thin film. The remaining part forms the magnetically sensitive part of the magnetoelectric transducer. Lead wire 3 of external drawer lead
is connected to the electrode 2 through a conductive resin 4. Generally, it is preferable to provide the compound semiconductor thin film on the substrate 5 because of its thinness. Further, if the surface of the compound semiconductor thin film that does not face the substrate is bare, it is likely to be scratched, so it is preferable to provide a protective layer in the same way as with ordinary semiconductors. FIG. 1A shows a cross-sectional view of a structure entirely molded with epoxy resin 6.
Further, FIG. 1B shows a top view of the same structure.

As the substrate 5, those conventionally used for magnetoelectric conversion elements can be used depending on the purpose of use.

For example, ferromagnetic substrates include pure iron plates, silicon steel plates, permalloy plates, and various ferrite plates. Further, as the non-magnetic substrate, a substrate made of metal, glass, ceramic, sapphire, etc., or a resin substrate can be used.

Further, as shown in FIG. 2, a portion of the compound semiconductor thin film 1 other than the conductive lead portion connection electrode 2 may also be made conductive in the shape of a short bar to have a short bar 7.

Further, as shown in FIG. 3, the conductive lead connection electrode 2 of the compound semiconductor thin film 1 and its substrate 5 are connected to a substrate 9 having film-like conductor leads 8.
The lead 8 and the electrode 2 are connected with the conductive resin 4. The connection portion, the electrode portion, and the compound semiconductor portion are covered with a protective film 10.

Another form is shown in FIG. In this example, the lead connection electrode 2 made into a conductor of the compound semiconductor 1, the lead wire 3 for connection thereto, and the conductive resin 4 have the same structure as in FIG. 1, but the substrate 5 and the semiconductor thin film 1, an insulating layer 11 is provided between the two. In this way, an insulating layer can also be provided between the substrate 5 and the semiconductor thin film 1. Further, it is a preferable form to increase the magnetic sensitivity by focusing the magnetic field on the magnetoelectric transducer, and this structure is also shown in FIG. Compound semiconductor thin film 1 forming a magnetoelectric conversion element
A magnetic convergence chip 12 made of a ferromagnetic material is placed on the surface of the magnetic head with an adhesive 13, for example. A ferromagnetic substrate is used as the substrate 5, and the entire structure is molded with a molding resin 14. Note that a non-magnetic substrate may also be used as the substrate 5 of the structure shown in FIG.

The magnetic convergence chip 12 may be made of a ferromagnetic material, and is particularly preferably made of a material having a high saturation magnetic flux density, such as pure iron or permalloy ferrite. The shape may be any shape, such as a rectangular plate, a disc, a cylinder, or a prismatic shape, depending on the purpose of use. In general, a symmetrical type with linear magnetic field convergence is preferred.

As shown above, it is generally preferable to provide the compound semiconductor thin film 1 on the substrate 5, and any exposed parts of the conductive resin 4, the electrode 2, and the compound semiconductor thin film 1 should be protected. Covering with a layer is a more preferable form because it prevents damage to the semiconductor and further increases the reliability of the connection. Such a protective layer may be provided by molding with a molding resin, a magnetic focusing chip may be used as a protective layer, or simply a third protective layer may be provided.
It may be coated as shown in the figure.

In the case of an inorganic coating layer, the material of the protective layer is glass, SiO ₂ , SiO,
Insulating and water-impermeable oxides such as GeO ₂ and Al ₂ O ₃ are preferable, and in the case of an organic coating layer,
Epoxy resins, phenolic resins, polyimides, polyamideimides, etc. can be preferably used.

Glass is used as an inorganic molding material for molding, but epoxy resin, polyimide resin, polyamide resin, etc. are preferably used as organic molding materials.

Next, the manufacturing method of the present invention will be explained.

The manufacturing method of the present invention is to irradiate a part of the compound semiconductor thin film with energy to make only the energy irradiated part of the compound semiconductor thin film conductive, form an electrode that makes ohmic contact with the compound semiconductor in the unirradiated part, and then This is a method for manufacturing a magnetoelectric transducer, characterized in that the electrode and an external lead are electrically connected using a conductive resin paste.

An example of this manufacturing process will be explained using FIG. 6. Energy is applied to a compound semiconductor thin film 1 formed on a substrate 5 through a mask 15 having a desired electrode shape (or by scanning) to a portion where an electrode portion 2 is to be formed. The portion of the semiconductor irradiated with energy is thus made conductive and forms the electrode 2. Arrows in the figure indicate energy irradiation.

Next, the electrode 2 thus formed and the lead 3 for external extraction are electrically connected using a conductive resin paste. Further, if necessary, the entire structure is molded with a molding resin to form, for example, a magnetoelectric transducer as shown in FIG.

The magnetoelectric transducer of the present invention described above has good ohmic contact between the lead connection electrode 2 and the compound semiconductor 1, and is electrically connected to the external lead without impairing its characteristics. In addition to having high sensitivity and high reliability, the manufacturing process is simpler than that of conventional magnetoelectric conversion elements, and can be mass-produced.

Next, the present invention will be described in detail with examples.
The present invention is not limited to these.

Example 1 An InSb vapor-deposited film with an electron mobility of 15,000 cm ² /v·sec was formed on a square ferrite substrate with a thickness of 0.5 mm and a side of 5 mm in a pattern as shown in Figure 1B (encircled by a thick line frame). did.

Next, a chrome mask made by vapor-depositing chromium was used on the glass plate, and a Xe lamp was used to irradiate flash light with a pulse width of 100 μsec.

Input electrode 2 made by making the semiconductor into a conductor in this way
A Hall element having output electrodes 21a and 21b was fabricated.

The width of the magnetic sensing part 2 was 1.5 mm and the length was 3.0 mm, and the output electrodes were taken out from both ends of the magnetic sensing part at a width of 0.3 mm. The input and output electrodes are large to facilitate attachment of lead wires to the outside.

Next, lead wires were attached to the input and output electrodes using conductive resin paste H-310 manufactured by Epoxy Technology Co., Ltd., and the entire device was molded with epoxy resin.

A Hall element of the present invention as shown in FIG. 1 was manufactured.

The Hall element manufactured in this way has an unbalanced voltage of 1.2 m when the input control current is 5 mA and the magnetic field is 0.
V, and the Hall output voltage was 150 mV when the input control current was 5 mA and the magnetic flux density was 1 KG.

Furthermore, as mentioned above, when we compared the case of the Hall element of the present invention in which the leads were connected using conductive resin paste and the conventional case in which the leads were connected by soldering, we found that there were no defects in the manufacturing process. decreased from 32% to 7%.

Example 2 On a ferrite substrate with a thickness of 0.5 mm, a width of 2 mm, and a length of 5 mm, a length of 4 with an electron mobility of 20000 cm ² /V・sec was placed.
An Insb vapor-deposited film with a width of 0.4 mm and a width of 0.4 mm was formed.

Next, a chromium mask made by vapor-depositing chromium was used on the glass plate, and flash light with a pulse width of 100 μsec was irradiated using a Xe lamp. In this way, shot bar electrodes with a width of 50 μm and an interval of 50 μm and external connection electrodes with a width of 0.4 mm and a depth of 0.5 mm are formed at both ends at the same time, and the magnetoresistive element of the present invention has a configuration as shown in FIG. I made it. A lead wire was attached to this element using conductive resin paste H-31D manufactured by Epoxy Technology Co., Ltd., and the element was molded with epoxy resin to produce an element of the present invention. Furthermore, for comparison, an element was manufactured using the conventional method of attaching lead wires by soldering and molding with epoxy resin, and the failure rate of both methods was compared, and the failure rate of the element of the present invention was 7%. In the comparative example, the defect rate was 35%. In addition, the change in resistance value due to the magnetic field of the magnetoresistive element of the present invention is as follows at a magnetic flux density of 2 K.G.
It was 41%.

Example 3 On a pure iron substrate with a thickness of 0.5 mm, a width of 2 mm, and a length of 5 mm, an electron mobility of 70000 cm ² /V・sec and a length of 4 mm and a width of
A 0.4 mm Insb single crystal thin film was bonded using epoxy resin.

Next, a chrome mask made by vapor-depositing chromium was used on the glass plate, and flash light with a pulse width of 200 μsec was irradiated using a Xe lamp. In this way, short bar electrodes with a width of 50 μm and a spacing of 50 μm and external connection electrodes with a width of 0.4 mm and a depth of 0.5 mm were simultaneously formed at both ends. Next, lead wires were attached to these elements using conductive resin paste H-31D manufactured by Epoxy Technology Co., Ltd., and the elements were molded with epoxy resin to produce the magnetoresistive element of the present invention. On the other hand, as a comparative example, an element with lead wires attached was made by soldering, and the results were compared.The defects in the step of attaching the lead wires were 6% in the present invention, but 42% in the comparative example. . The change in resistance value of the magnetoresistive element of the present invention was 95% at a magnetic flux density of 2K.G.

[Brief explanation of the drawing]

FIG. 1A, FIG. 2, FIG. 3, FIG. 4, and FIG. 5 are sectional views showing different forms of the magnetoelectric transducer of the present invention. FIG. 6 is a sectional view showing the manufacturing process of the magnetoelectric conversion element of the present invention, and FIG. 1B is a top view of the magnetoelectric conversion element of FIG. 1A. 1 is a compound semiconductor thin film, 2 is an electrode for connecting a lead portion, 3 is a lead for external extraction, and 4 is a conductive resin.

Claims (1)

[Scope of Claims] 1. In a magnetoelectric conversion element made of a compound semiconductor thin film, at least the electrode for connecting the lead portion is formed by making a part of the compound semiconductor thin film conductive by irradiating energy, and the electrode for connecting the lead portion has an external conductor. A magnetoelectric transducer characterized in that a drawer lead is connected by a conductive resin. 2. By irradiating a part of the compound semiconductor thin film with energy, only the energy irradiated part of the compound semiconductor thin film is made into a conductor, an electrode is formed that makes ohmic contact with the compound semiconductor in the unirradiated part, and then the electrode and the external lead are connected. 1. A method for manufacturing a magnetoelectric transducer, characterized by electrically connecting the two using a conductive resin paste.