JP2000322716A - Magneto-resistance effect type magnetic head and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent dielectric breakdown by electrically conducting one of the electrode films for guiding an electric current to a reproducing element, to a shield through a fuse to be melted and by releasing a short-circuit in an arbitrary process. SOLUTION: In the manufacturing process of a reproducing element, the electrode films 6a, 6b formed at both ends of a SAL bias type MR element 5 are connected to conductive films 6c, 6d respectively through fuses 5a, 5b. The conductive films 6c, 6d are connected to a bottom shield and a mid shield respectively through contacting terminals 9a, 9b. The electrode films 6a, 6b are provided with terminals 10a, 10b. These terminals 9a, 9b, 10a, 10b are each connected to an electrode pad formed by plating. By a fuse melting device, the fuse 5b is melted by causing an electric current to flow in such route as the terminal 9b/fuse 5b/terminal 10b, while the fuse 5a in such route as the terminal 9a/fuse 5a/terminal 10a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive magnetic head having a recording head and a reproducing head, and more particularly to a magnetoresistive magnetic head provided with a structure for preventing a reproducing element from being damaged by static electricity.

[0002]

2. Description of the Related Art The recording density of hard disk drives has been increasing year by year, and the magnetic heads used have rapidly been replaced by inductive heads with separate recording / reproducing heads. The recording / reproducing separation type head has a reproducing head and an inductive recording head. This reproducing head uses a reproducing element having a magnetoresistance effect. Because of this feature, the read / write separation type head is called a magnetoresistive effect type magnetic head.
Hereinafter, the reproducing element having the magnetoresistive effect is referred to as an MR element, and the magnetoresistive head is referred to as an MR head. FIG. 19 is a sectional view showing an example of a conventional MR head.
FIG. 20 is a perspective view illustrating an example of a conventional MR head.

In FIG. 20, an alumina insulating film 96, a lower shield 94, an insulating film, an MR element 102, and a nonmagnetic substrate 95 made of alumina / titanium carbide or the like are provided.
Intermediate shield 9 having a function as an insulating film and a lower magnetic pole
3. It has an insulating film serving as a recording gap and an upper magnetic pole 104. Although an insulating film for insulating between the lower shield 94, the MR element 102, and the intermediate shield 93 is not shown, it is actually filled between the respective films. An insulating film (recording gap) is provided between the intermediate shield 93 and the upper magnetic pole 104, and functions as a magnetic gap of the inductive recording head. Further, a thin-film coil 100 is arranged between the intermediate shield and the upper magnetic pole via an insulating film. The intermediate shield 93 and the lower shield 94 are thin films used as magnetic shields, and have an MR element 102 and an electrode film 103 therebetween.
And a reproducing gap formed of an insulating film surrounding the bias film 101, and also functions as a magnetic gap of the reproducing head. FIG. 19 is a partial cross-sectional view of the conventional MR head as shown in FIG. 20 when viewed from the medium facing surface. The medium facing surface corresponds to a plane (YZ plane) perpendicular to the arrow x in the figure. Hereinafter, a thin film that functions as a magnetic shield is referred to as a shield.

The MR head described with reference to FIG. 20 is formed by laminating thin films on a substrate called a wafer, and is formed in a number of thousands or more. The wafer is cut into substrates each having one MR head. The slider is formed by processing the air bearing surface of the substrate so as to be flush with the medium facing surface of the MR head. Therefore, the manufacturing process of the MR head can be roughly classified into a wafer process for laminating thin films and a slider process for cutting the wafer to form a floating surface. Further, the slider is supported by a suspension called a gimbal and provided in a hard disk drive. In a hard disk drive, a supported slider flies above a rotating magnetic disk and is used for recording and reproducing magnetic information with an MR head.

In the field of MR heads, the following techniques are known as antistatic techniques. JP-A-9-91623
Japanese Patent Application Laid-Open Publication No. Hei 11 (1995) discloses an MR head provided with a short circuit that short-circuits a pair of electrodes without using an MR element. The drawing of this publication describes a structure in which the deformed convex portion of the shield is directly joined to the electrode film. JP-A-8-167123 discloses a magnetic head in which a plurality of head elements are electrically connected to an electrode film, an upper shield and a lower shield, formed on a substrate, and the formed elements are separated one by one. A manufacturing method is disclosed. JP-A-10-2473
No. 07 discloses a magnetic head having a resistance element for electrically connecting a lead and a shield. The electric resistance value of this resistance element is set to a high value within the range of 100 [kΩ] to several [MΩ].

[0006]

The MR head uses a thin film made of a magnetic material or a metal material. These thin films are easily charged in the manufacturing process. As the thickness of the thin film becomes thinner with the miniaturization of the MR head, electrostatic breakdown easily occurs. In particular, electrostatic breakdown occurs between the read element and the shield, damaging the MR head. Electrostatic breakdown refers to a phenomenon in which when a potential difference between a charged thin film and another thin film increases, an excessive current flows through a thin insulating film disposed between the thin films or the thin film itself, and the thin film is destroyed. Electrostatic breakdown is also called dielectric breakdown. Some conventional MR heads are short-circuited or the like in order to prevent electrostatic breakdown between the reproducing element and the shield. However, effective prevention of electrostatic breakdown has not yet been achieved throughout the manufacturing process of the MR head.

In the prior arts of JP-A-9-91623 and JP-A-8-167123, the electrode of the reproducing element and the shield are short-circuited. However, the short circuit must be cut by machining, and the timing of cutting is limited to the step of cutting the wafer. Further, Japanese Patent Application Laid-Open No. Hei 10-247307 does not mechanically cut a short circuit, but leaves a resistive element having a high electric resistance value. The remaining resistance element becomes a parallel circuit that causes noise to the reproduction element.
SUMMARY OF THE INVENTION It is an object of the present invention to provide an MR head which prevents electrostatic breakdown without depending on the step of cutting a wafer or a slider to open a short circuit.

[0008]

An MR head according to the present invention comprises:
In an MR head in which a reproducing element having a magnetoresistive effect is provided between two shields via an insulating film, at least one of an electrode film for guiding a current to the reproducing element has
It is characterized by being electrically connected to the shield via a fuse to be blown. Here, the current flows to obtain an output from the reproducing element. When manufacturing the magneto-resistance effect type magnetic head, the fuse can be blown by supplying an electric pulse to the fuse. Further, when manufacturing the magneto-resistance effect type magnetic head, the fuse can be blown by irradiating the fuse with the laser.

Another MR head of the present invention has a structure in which a reproducing element having a magnetoresistive effect is provided between two shields via an insulating film, and an electrode film for guiding a current to the reproducing element. At least one of the MR heads has a structure in which the fuse is electrically connected to the shield via a fuse to be blown, wherein the fuse has a residual mark that has been blown. Here, the residue means a fuse that has been blown to disconnect the main part, a fragment of the melted fuse, a groove or a hole or a notch remaining in the insulating film covering the fuse, and a film in the groove. It also includes the adhered fuse material, undissolved fuses attached to the electrode film or shield like burrs, and the like. A state in which most of the fuse is melted but the connection of the fuse remains as a very thin line is also referred to as a residual mark. The residue in this case is a state where the resistance value of the fuse is 1 [MΩ] or more and the current shunted through the fuse can be substantially ignored.

Another MR head according to the present invention has at least four or more electrode pads for externally supplying current to a reproducing element or a recording element, and a current or current is supplied between at least two of the electrode pads. By applying a voltage, a fuse connected to the two electrode pads is blown. The connection between the electrode pad and the fuse may be either a direct connection or an indirect connection via another conductive member.

Another MR head according to the present invention has a total of M electrode pads for energizing a recording element and an electrode pad for energizing a reproducing element, and is used for energizing a fuse or inspecting a fuse. , M is 4 or more, and N is 2 or more. When the fuse is energized or tested, a current is applied between one of the N electrode pads and one of the M electrode pads.

For example, for a spin valve type MR head, M ≧
4 and N ≧ 2, and the tunnel junction type MR head has M ≧
4 and N ≧ 2. The value of M is a measuring element related to measurement of the amount of polishing of the slider, measurement of the distortion of the slider or the MR element, measurement of the temperature of the slider or the MR element, and the like. It may include connected electrode pads.

Another MR head of the present invention has at least four or more electrode pads in order to externally supply current to a reproducing element or a recording element, and a current or current is supplied between at least two of the electrode pads. An MR head capable of blowing a fuse connected to the two electrode pads by applying a voltage, wherein the fuse has a blown residue.

Another MR head of the present invention has at least four or more electrode pads in order to externally supply current to a reproducing element or a recording element, and at least two or more of the four or more electrode pads are used. Connected to the playback element,
A fuse connected to the two electrode pads is blown by applying a current or a voltage between at least two of the electrode pads.

According to the method of manufacturing an MR head of the present invention, at least four or more electrode pads are provided in order to externally supply current to a reproducing element or a recording element, and a current is supplied between at least two of the electrode pads. Alternatively, by applying a voltage, in a method of manufacturing an MR head in which a fuse connected to the two electrode pads is blown, a current pulse or a voltage pulse is used by using a current pulse or a voltage pulse during the process of manufacturing the MR head or after the manufacturing process is completed. The method is characterized in that a fuse is blown, and thereafter, a short circuit or a withstand voltage between the read element and the shield is inspected.

Here, the steps in the course of manufacturing the MR head include, for example, a step of cutting a row bar or a slider from a wafer provided with the MR head, a step of cutting a slider from the row bar, and the like. Of course, the fuse can be blown at any time during the manufacturing process or at any time after the end of the manufacturing process. In these steps, the fuse is blown without changing the outer shape or appearance.

According to another MR head manufacturing method of the present invention, a reproducing element having a magnetoresistive effect has a structure provided between two shields via an insulating film, and a current is led to the reproducing element. Method for manufacturing an MR head having a structure in which at least one of the electrode films is electrically connected to the shield via a fuse that is blown. Alternatively, the fuse is blown using a voltage pulse. Further, it is desirable that a short circuit or a withstand voltage between the read element and the shield be inspected thereafter.

According to another method of manufacturing an MR head of the present invention, at least four or more electrode pads are provided in order to externally supply current to a reproducing element or a recording element, and between at least two of the electrode pads. A fuse connected to the two electrode pads can be blown by applying a current or a voltage to the fuse, and the fuse has a blown residue. Melting the fuse using a current pulse or a voltage pulse during a process of manufacturing the MR head or after completion of the manufacturing process, and thereafter inspecting a short circuit or a dielectric strength between the reproducing element and the shield. I do.

According to the present invention, a fuse formed of a thin film can be formed simultaneously with the MR element. That is, a thin film or a multilayer film serving as a fuse can be formed simply by replacing the reticle without increasing the number of manufacturing steps. The reticle is a photomask used in a process called photolithography used for forming a thin film.

In the present invention, the shield is grounded from the electrode films arranged on both sides of the read element via a conductive member (fuse). Grounding refers to electrical conduction. Since it is necessary to cut the conductive member later, in the present invention, the shape and the electric resistance are designed so that the conductive member functions as a fuse. However, in order to avoid damaging the read element when the fuse is blown, the power consumed by the fuse is consumed by other members (including the read element) when a current is supplied to an electric circuit including the fuse. Make it larger than the power. Therefore, it is desirable that the electric resistance value of the fuse is set to be larger than the electric resistance value of the reproducing element.

In order to make the electric resistance of the conductive member serving as the fuse larger than the electric resistance of the reproducing element, it is desirable to use a fuse narrower than the MR element. Here, the width is a width in a direction perpendicular to the direction in which the current flows. By reducing the width, the electrical resistance of the fuse can be increased as compared with the MR element, even if the fuse has the same film configuration and the same composition as the MR element. Therefore, if the electric resistance of the fuse is made larger than that of the MR element when a current flows through the fuse through the MR element, the fuse is heated first and blows, but the MR element is not overheated and damaged. Not receive. In order to make the electric resistance of the fuse smaller than that of the MR element, a method of shaving the fuse by selective etching to reduce the thickness may be used. In addition,
When a current pulse is supplied to the fuse without passing through the MR element, there is no problem even if the electric resistance of the MR element is larger than the electric resistance of the fuse.

The electrical connection of the read element (MR element) to the shield prevents a potential difference from occurring between the read element and the shield, and causes a current to flow through the read element due to electrostatic breakdown between the read element and the shield. This controls the phenomenon of flowing. This technique is an effective means for preventing electrostatic destruction of the reproducing element in particular, and can eliminate the influence of charging in the middle of the manufacturing process of the MR head.

However, when the MR head is used in the HDD device, if there is continuity between the reproducing element and the shield, a weak current flows between the reproducing element and the shield, causing noise to the reproduced signal. Therefore, it is desirable that the continuity between the reproducing element and the shield is grounded (connected) during the manufacturing process and is insulated after the manufacturing process. In addition, in a state where the reproducing element and the shield are insulated, it is necessary to guarantee a desired withstand voltage in order to prevent electrostatic breakdown which occurs when handling the device. Therefore, it is necessary to insulate the read element from the shield at the final stage of the manufacturing process and measure the withstand voltage. Although the grounding of the reproducing element mentioned here is a known technique, the MR element is grounded during the middle of the manufacturing process until the manufacturing process is completed, and the grounding is released without deforming the appearance and the insulating state is established. Is an unprecedented new technology.

The principle of cutting a fuse is to blow the fuse using heat generated by current flowing through the fuse, similarly to a general electric fuse. However, the difference from the general case is that the current mainly used for cutting is not a steady current but a current pulse. This is because, when a steady current is used, a voltage is applied between the reproducing element and the shield immediately after the fuse is cut, which may cause electrostatic breakdown of the reproducing element and the shield. This results in destroying the read element, contrary to the purpose of the fuse of the present invention. On the other hand, when a current pulse is used, the desired insulation can be maintained without applying a voltage between the reproducing element and the shield immediately after the fuse is blown under an appropriate pulse width condition. Become.

In the present invention, the MR head is a name indicating a magneto-resistance effect type magnetic head, and includes a magnetic head including a reproducing element utilizing a magneto-resistance effect. Therefore, it is also possible to replace the head with an element for recording or reproducing using light in addition to the reproducing element. Further, the term “fuse to be blown” is used simply as a term for a fuse or a term for a fuse that can be blown. The term "electrically conductive" means in electrical contact,
Alternatively, it is used to include the meaning that a current can flow between the two. Further, the shield includes one that simply functions as a shield and one that also has a function other than the shield. Also, energization means flowing a current or applying a voltage. The “reproducing element having a magnetoresistive effect” is used as a term including a reproducing element utilizing the fact that the electric resistance changes when a magnetic field is applied.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An MR head according to the present invention will be described below with reference to the drawings. FIG. 1 is a plan view illustrating an embodiment of a reproducing element of an MR head according to the present invention. FIG. 2 is a cross-sectional view for explaining a manufacturing process of the MR head of FIG. 3 and 4 are schematic diagrams illustrating a circuit for cutting a fuse by the MR head of the present invention. FIG. 5 shows another M according to the present invention.
FIG. 2 is a plan view illustrating an embodiment of a reproducing element of an R head. FIG. 6 is an equivalent circuit diagram of the fuse blowing device. FIG. 7 is a plan view of one embodiment of the reproducing element of the MR head of the present invention. FIGS. 8 and 9 are perspective views of the slider of the MR head according to the present invention, and illustrate electrode pads provided on the slider. FIG. 10 is a sectional view of a spin valve element applicable to the MR head of the present invention. FIG. 11 is a graph illustrating the relationship between the electric resistance value of the fuse and the applied voltage. FIG. 12 is a graph illustrating the relationship between the current pulse width applied to the fuse and the peak current. 13 to 1
8 is Vb, Vb with respect to the fuse width W and the fuse length L.
It is a graph which shows each relation of f and Jbf.

(Embodiment 1) Referring to FIG. 1, the structure of a reproducing element of an MR head will be described. As this MR element, a SAL bias type MR element was used. Although not shown, SAL
The bias type MR element has a soft magnetic bias film (SAL
Film), a non-magnetic metal film, and a soft magnetic film (M
R film) and a permanent magnet bias film provided at both ends of the three-layer film. Electrode films 6a and 6b were provided on both ends of the MR element 5, respectively. Each of the electrode films 6a and 6b was connected to the conductive films 6c and 6d via fuses 5a and 5b. The shield 3 (bottom shield) was connected to the conductive film 6c via the contact terminal 9a. The shield 8 (mid shield) was connected to the conductive film 6d via the contact terminal 9b. A terminal 10 is provided on each of the electrode films 6a and 6b.
a and 10b were provided. The width d of the fuses 5a and 5b is M
The R element was formed to have a dimension smaller than the width d0 in the depth direction. The so-called track width Tw is M in the direction perpendicular to do.
This is the width of the R element. The overall configuration of the MR head including this reproducing element was the same as that shown in FIG.

FIG. 2 shows that the MR having the reproducing element of FIG.
The head manufacturing process will be described. First, an insulating film 2 of alumina was formed on a nonmagnetic substrate 1 made of alumina titanium carbide by sputtering (a). CoT on insulating film 2
An aZr soft magnetic film was formed by sputtering, and the soft magnetic film was patterned by photolithography to obtain a shield 3 (b). An alumina insulating film 4 was formed on the shield 3 by sputtering. Subsequently, a multilayer magnetic film constituting the MR element was formed by sputtering. This magnetic film formed on the insulating film 4 was patterned to form the MR element 5 and each of the fuses 5a and 5b in a stripe shape (c).

Next, a part of the insulating film 4 was etched by ion milling to form a contact hole. Subsequently, a conductive metal film was formed by sputtering, and this was patterned to form electrode films 6a and 6b and conductive films 6c and 6d simultaneously. A part of the conductive film 6d filled in the connection hole was a terminal 9a. Each of the electrode films 6a and 6b conducts with the MR element via the fuses 5a and 5b. The conductive film 6d was electrically connected to the shield 3 (d). Next, a second insulating film 7 was formed, and a contact hole was made in a part thereof. The shield 8 was formed by electroplating so as to pass through the contact hole, and the shield 8 was electrically connected to the conductive film 6c (e).

Next, the structure of the recording head was formed on the second shield. That is, on the second shield, a gap film, a resist insulating film, a thin film coil, a resist insulating film, and an upper magnetic pole film were sequentially formed. The structure of the recording head is the same as the configuration shown in FIGS. Further, the terminals 10a and 10b of the electrode film, the terminals 9a and 9b connecting the shield (lower shield or mid shield) and the fuse, and both ends of the thin film coil are connected to the electrode pad via another conductive member (lead film). It was made electrically conductive. The electrode pads were formed by electroplating. An alumina protective film was coated so as to cover the periphery of the electrode pad and the top of the MR head.

(Embodiment 2) FIG. 3 is a schematic diagram of a circuit for supplying a current pulse to a fuse in the MR head of the present invention. In the present embodiment, a circuit including an MR element was used when a current pulse was applied to a fuse after cutting a slider provided with an MR head. That is, the fuse blower 21 blows a current pulse through a circuit passing through the terminal 9b / fuse 5b / electrode film 6b / MR element 5 / electrode film 6a / fuse 5a / terminal 9a to blow the fuse. Although not shown in FIG. 3, the fuse blowing device 2
Electric current was passed between the terminal 1 and the terminal via a conductive member (lead film) for guiding a current or an electrode pad exposed on the side surface of the slider.

In this method, an electric resistance value of the same circuit was measured after a current pulse for fusing was passed. The electric resistance value measured after fusing was pseudo-infinite, and the measuring device determined that the circuit was open. Therefore, it is also possible to perform the operation with one device that also serves as the fuse blowing device 21 and the inspection device that measures the electric resistance value. Since this circuit passes through the MR element 5, the two fuses 5b and 5a are cut at the same time. However, it is essential that the fuse be cut with a current pulse or a voltage pulse that does not damage the MR element. Since the blow of the fuse that passes first is started before the blow of the fuse that passes next, the blow state of the fuse is slightly different. The current pulse applied here will be described later.

(Embodiment 3) FIG. 4 is a schematic diagram of another circuit for supplying a current pulse to a fuse. In FIG. 4, a current pulse was caused to flow between the terminal 9b / fuse 5b / terminal 10b of the electrode film by the fuse blowing device 22 to blow one of the fuses 5b. Subsequently, a current pulse was also applied between the terminal 9a / fuse 5a / terminal 10a of the electrode film to blow the other fuse 5a. In this method, a current pulse or a voltage pulse is applied to each fuse, so that no current flows through the MR element. Compared to the method of the second embodiment, the blown state of the two fuses can be made uniform. Also, two fuse blowing devices are prepared, and a fuse 5a is provided.
If the fuse 5b is blown at the same time, the process can be shortened.

Embodiment 4 FIG. 5 shows another MR according to the present invention.
FIG. 3 is a plan view illustrating an embodiment of a reproducing element of a head. This MR head includes an MR element 5 having an electrode film 6a and an electrode film 6b connected to both ends, and a shield 3b and a shield 8b.
It has a configuration provided between them. Further, a configuration is added in which the electrode film 6b and the shield 8b are electrically connected, and the shield 8b (mid shield) and the shield 3b (bottom shield) are electrically connected. In FIG. 5, the shield 3b is arranged below the MR element 5 via an insulating film, and the shield 8b is arranged above the MR element 5 via an insulating film. A fuse 5c was provided between the electrode film extension 6f and the connection film 6g. The electrode film extension 6f was provided integrally with the electrode film 6b. The connection film 6g was electrically connected to the shield 8b. The shield 3b and the shield 8b were electrically connected at a connection portion 9n penetrating the insulating film. The shield 8b and the connection film 6g were electrically connected at a connection portion 9m penetrating the insulating film. After the structure including the reproducing element was provided on the wafer, the wafer was cut to obtain a row bar. This row bar was polished to remove the portion above the line AA. Therefore, in the state of the slider, the fuse 5c was removed. In the configuration of the fourth embodiment, the fuse 5c is mechanically removed in the row bar process. However, since the fuse 5c is arranged near the MR element, the electrostatic breakdown of the MR element can be more effectively prevented in the wafer process. Was.

FIG. 6 shows an equivalent circuit diagram of the fuse blowing device according to the present invention. The operation of the fuse blowing device 21 will be described. First, by connecting the switch to the terminal b, the capacitor C is charged to a predetermined amount by the variable power supply Vc. Next, when the switch is switched to the terminal a, the resistance R
, The amount of charge stored in the capacitor C can be released as a current pulse. Output V of fuse blowing device
out changes depending on the ratio of R to the fusing circuit for applying the current pulse. In the embodiment according to the present invention, a fuse blowing device equivalent to the equivalent circuit shown here was used. The value of the condenser C was set to about 1 to 100 [nF]. The value of the resistor R was set to about 150 to 500 [Ω]. The initial resistance value Ro of the fuse is about 100 [Ω] or less,
The resistance value Ra of the fuse measured after the fusing step is 1 *
If it is 10 ⁶ [Ω] or more, it is determined that the fuse has blown.

(Embodiment 5) FIG. 7 shows another embodiment. In the reproducing element of this MR head, the MR element 5 and the electrode film are arranged between the shields 3 and 8 via the insulating film, and most of the fuses are arranged outside from between the shields 3 and 8. . When most of the fuse connecting the electrode film and the terminal is arranged between the shields, heat generated in the fuse by the current pulse is taken by the shield. Unless more energy is supplied to the fuse as a current pulse in anticipation of this heat loss, it is difficult to blow the fuse.

Therefore, by adopting the configuration shown in FIG. 7, it is possible to prevent heat from being taken away by the shields 3 and 8, and to blow the fuse with a current pulse having less energy. The shape of the fuse disposed outside the shield is not limited to a straight line, but may be a combination of a plurality of straight lines, a curved line, a combination of a curve and a straight line, or an L-shape. In the case of the U-shaped fuse, the terminal 9a and the terminal 9b could be constituted by a part of the shield. In the case of a straight fuse, the terminal 9a
And 9b, and a conductive film for connecting the terminal and the shield were provided separately from the shield.

Embodiment 6 FIG. 8 shows an MR head 3 according to the present invention.
7 shows a perspective view of a slider 38 provided with 7. In the figure, the disk on the left is a wafer 30 on which a number of MR elements are formed. The slider 38 cut out from the wafer 30 has six electrode pads. Electrode pads 31 and 32
Was used to supply a recording current to a thin film coil that excites the magnetic pole. The electrode pads 33 and 34 were used to supply a reproduction current to the MR element via the electrode film. The electrode pads 35 and 36 were used for supplying a current pulse or a voltage pulse to a fuse provided between the electrode film and the shield. In this configuration, the MR element is formed on the wafer until the slider is formed.
The element and the shield were prevented from being electrostatically damaged, and the fuse was blown when the slider was manufactured.

It is also possible to provide a gimbal or the like on the slider to produce an HGA (head gimbal assembly) and then blow the fuse. When blowing the fuse, a combination of different electrode pads can be selected. That is, in the method corresponding to FIG. 3, a current pulse is applied between the electrode pad 35 and the electrode pad 36 to blow the fuse at once. In the method corresponding to FIG. 4, the electrode pad 35 and the electrode pad 3
4 and one of the fuses was blown, and then the other of the fuses that was passed between the electrode pad 36 and the electrode pad 33 was blown.

(Embodiment 7) FIG. 9 is a perspective view of another slider according to the present invention. In the figure, the disk on the left has many M's.
This is a wafer 40 on which an R element is formed. This wafer 4
The slider 48a cut out from 0 has six electrode pads. The electrode pads 41 and 42 were used to supply a recording current to a thin-film coil for exciting the magnetic pole. The electrode pads 43 and 44 were used to supply a reproduction current to the MR element via the electrode film. Electrode pads 45 and 46
Was used to supply a current pulse or a voltage pulse to a fuse provided between the electrode film and the shield.

With this configuration, in the step of forming the MR element on the wafer, the electrostatic breakdown of the MR element and the shield can be prevented. In FIG. 9, a dotted line indicates a cutting line separating the slider piece 48b from the slider 48a. Slider 4
An air bearing surface was formed on the lower surface of 8a (not visible in the figure).
The fuse is blown just before cutting from the wafer 40, and the slider piece 48b is cut along the dotted line simultaneously with the cutting of the wafer.
Can also be separated. However, if the fuse is blown before the wafer 40 is cut, there is a possibility that the MR element is electrostatically damaged in the process of processing the slider. Therefore, the slider was cut along the dotted line after finishing the slider processing step.

Next, an experiment in which the fuse according to the present invention was studied will be described with reference to FIG. Fuse pattern element with width d = 1 [μm] (electrical resistance per length is 13 to 15)
[Ω / μm]), a current pulse having a time width of 5 μs was applied, and the voltage at which the fuse pattern element was blown was examined. Here, the fuse pattern element refers to a fuse formed of a multilayer film similar to the MR element. In FIG. 11, the vertical axis represents the fuse resistance [Ω] and the horizontal axis represents the applied voltage [V]. In the figure, the fuse pattern elements according to the samples numbered from 1 to 4 were blown within the applied voltage range of 8 to 12 [V]. Pulse width 5 [μs], voltage 10 [V]
Is about 17 [mA], and 0.85
[ΜWs] of energy was consumed. In the wafer process for manufacturing the reproducing element, the track width of the MR element is formed wider than the final dimension. This is because the width of the reproducing element is reduced in the row bar process or the slider process. When a fuse having the same shape as the MR element is formed in the wafer process, the width of the fuse is about 4 to 5 [μm], which is 4 to 5 times the width of the fuse pattern element shown in FIG. In order to secure the same current density as that of the experiment of FIG. 11 with a wide fuse, a peak current of about 70 [mA] is required, and 3.4 energy is required as the energy required for fusing.
[ΜWs] is consumed. Therefore, when a current pulse is applied at an applied voltage of about 10 [V] at the end of the wafer process,
It was found that the fuse was blown and the read element was not affected.

FIG. 12 shows the results of a cutting experiment performed by using a pulse width and a peak current as parameters for cutting a fuse by a current pulse. The vertical axis of the figure shows the peak current [A] which is the maximum value of the current pulse, and the horizontal axis shows the pulse width [sec] which is the half width of the current pulse. Both the vertical and horizontal scales are indicated by exponents, for example, -7.
Represents 10 ^-7 . The figure shows the fuse pattern width d =
The case where 1 [μm] and d = 4 [μm] are shown. As the pulse width decreased, the magnitude of the peak current required for fusing increased.

When the pattern width is compared, d = 4 [μ]
m] is four times the peak current of d = 1 [μm], and it has been found that the required peak current increases in proportion to the pattern width. This relationship was kept constant when the pulse width was 5 * 10 ^-9 [sec] or more. The range in which the fuse functions and the threshold value of the peak current at which the cutting pulse does not affect the read element can be set in the range shown by the hatched area in FIG.

(Embodiment 8) In the reproducing element of the MR head of the present invention described above, instead of the SAL bias type MR element, a spin valve type MR element, and a tunnel junction type in which an insulating film is sandwiched between two soft magnetic films. An MR element, a GMR element in which a nonmagnetic film and a magnetic film are alternately stacked, or the like can be used. These MR elements have a recording density of 6 [Gb / i
It is necessary to reduce the size and thickness of the recording medium in order to correspond to a recording medium of about n ² ] or more, and the track width Tw is specified to be several [μm] or less. Therefore, when the above fuse was applied, electrostatic breakdown could be more effectively prevented.

The spin valve type MR element has a four-layer structure including a diamagnetic film, a magnetic film, a non-magnetic metal film and a magnetic film. FIG. 10 shows a spin-valve MR element according to an embodiment of the present invention. This spin-valve MR element has a C
A four-layer film in which an antiferromagnetic film 82a of rMnPt, a magnetic film 82b of NiFeCo, a nonmagnetic metal film 82c of Cu, and a magnetic film 82d of NiFe are sequentially laminated, and both ends of the four-layer film are etched. And a bias application permanent magnet film 81 bonded to the inclined surface. An electrode film 83 was provided on each of the permanent magnet films 81. As the spin-valve MR element, an element obtained by improving the configuration in FIG. 10 can be used. Specifically, the magnetic film is a multilayer film made of a metal material or a magnetic material,
A dual spin-valve element in which two spin-valve MR elements are stacked in pairs with the anti-ferromagnetic film 82a or the magnetic film 82d being shared can be used.

(Embodiment 9) For a length L [μm] and a width W [μm] of a stripe-shaped fuse, L / W = 10/1,
Three patterns of 5/1 and 2.5 / 1 were formed. When formed in a stripe shape, the fuse of the multilayer film is Ta (5 nm) / N
iFe (5 nm) / CoFe (1 nm) / Cu (2.5 nm)
/CoFe(2nm)/CrMnPt(22.5nm)/T
a (3 nm) was used. This is the configuration of the fuse in the spin valve type MR head. When a pulse current was applied to these fuses, the fuses could be blown. 13 to 18 show data obtained by examining the electrical characteristics of such a fuse by simulation.

FIG. 13 shows the fuse width dependence of Vb.
FIG. 14 shows the dependence of Vb on the fuse length. Vb is the voltage charged to the capacitor C in the fusing device and is a value required for fusing the fuse. According to FIG. 13, when the fuse width is increased, it is necessary to increase Vb in proportion thereto. FIG. 14 shows that when the fuse length L is larger than about 1 [μm], Vb does not increase so much and can be regarded as substantially constant. When L is smaller than 0.6 [μm], higher Vb is required. 13, 15 and 17 show that L = 0.6 [μm] and L = 1.0 [μm].
m] are simulated.
FIGS. 14, 16 and 18 show that W = 1.0 [μm] and W =
The simulation is performed for two cases of 1.5 [μm].

FIG. 15 shows the dependence of Vbf on the fuse width.
FIG. 16 shows the dependence of Vbf on the fuse length. Vbf is a voltage applied to the fuse when the fuse is blown. FIG. 15 shows that Vbf relating to the fuse itself is substantially constant even when the width W is changed. According to FIG.
Is larger than about 1 [μm], Vbf is also increased. Next, FIG. 17 shows the dependence of Jbf on the fuse width, and FIG. 18 shows the dependence of Jbf on the fuse length. Jbf is the current density of the fuse when the fuse is blown.
According to FIG. 17, it is found that the current density Jbf flowing through the fuse is substantially constant even when the width W is changed. According to FIG.
It can be seen that when the length L is larger than about 1 [μm], Jbf becomes larger.

The following can be said from the above simulation. That is, if L is too small, heat generated by a circuit connecting the fuse and the electrode pad is taken, so that
It is believed that higher Jbf is required. Therefore, L is 1
[Μm] or more is desirable. For example, 15 [μ
m]. On the other hand, since Vb can be controlled by the resistance of the external circuit, W can be freely selected in the range of 0.5 to 2 [μm] by focusing only on the fuse. Further, in consideration of the accuracy in forming the fuse, the length L = about 2 to 3 [μm] and the width W = 1
[Μm] is preferable. According to the simulation, when the current density is increased, the temperature in the fuse is equivalent to 150 to 300 ° C. when L = 5 to 15 μm. However, this temperature is consumed as energy for blowing the fuse, and does not affect other members constituting the MR head.

(Embodiment 10) An embodiment in which a fuse is blown by another means will be described. The MR element shown in FIG.
After forming the head, the fuses 5a and 5b were irradiated with a laser to blow the fuses. This method
In any step after the wafer step or the slider step, the fuse can be blown. In this case, the electrode pad led from the fuse to the surface of the slider is used as an inspection means for electrically confirming the fusing / connection of the fuse. When irradiating a laser to the fuse through an alumina protective film provided on the MR head, it is desirable that the wavelength of the laser does not damage the alumina film and melts the material forming the fuse.

[0052]

As described above, by using the structure of the present invention, it is possible to open a short circuit in an arbitrary step in a manufacturing process of an MR head, and to provide an MR head in which electrostatic breakdown is prevented. I got it.

[Brief description of the drawings]

FIG. 1 is a plan view of a reproducing element of an MR head according to the present invention.

FIG. 2 is a cross-sectional view illustrating a manufacturing process of the MR head of the present invention.

FIG. 3 is a schematic diagram illustrating a circuit for blowing a fuse with the MR head of the present invention.

FIG. 4 is a schematic diagram illustrating a circuit for blowing a fuse in the MR head of the present invention.

FIG. 5 is a plan view illustrating an embodiment of a reproducing element of another MR head according to the present invention.

FIG. 6 is an equivalent circuit diagram of the fuse blowing device according to the present invention.

FIG. 7 is a plan view of an embodiment of the reproducing element of the MR head of the present invention.

FIG. 8 is a perspective view of a slider of the MR head of the present invention.

FIG. 9 is a perspective view of a slider of the MR head of the present invention.

FIG. 10 is a sectional view of a spin valve element applicable to the MR head of the present invention.

FIG. 11 is a graph illustrating a relationship between an electric resistance value of a fuse and an applied voltage.

FIG. 12 is a graph illustrating a relationship between a current pulse width applied to a fuse and a peak current.

FIG. 13 is a graph showing the dependence of Vb on the fuse width W.

FIG. 14 is a graph showing the dependence of Vb on the fuse length L.

FIG. 15 is a graph showing the dependence of Vbf on the fuse width W.

FIG. 16 is a graph showing the dependence of Vbf on the fuse length L.

FIG. 17 is a graph showing the dependence of Jbf on the fuse width W.

FIG. 18 is a graph showing the dependence of Jbf on the fuse length L.

FIG. 19 is a sectional view of a conventional MR head.

FIG. 20 is a perspective view of a conventional MR head.

[Explanation of symbols]

1 non-magnetic substrate, 2 insulating film, 3 3b shield, 4
Insulating film, 5 MR element, 5a 5b 5c fuse, 6a 6b electrode film, 6c 6d conductive film, 6f
Electrode film extension, 6g Connection film, 7 Second insulating film, 8
8b shield, 9a 9b terminal, 9m 9n connection portion, 10a 10b terminal, 21 22 fuse blowing device, 30 40 wafer, 31 32 41 42
Electrode pad, 33 34 43 44 electrode pad,
35 36 45 46 Electrode pad, 37 MR head 38 slider, 48a slider, 48b
Slider piece, 82a antiferromagnetic film, 82b magnetic film, 82c nonmagnetic metal film, 82d magnetic film, 81
Permanent magnet film, 83 electrode film.

Claims (9)

[Claims] In a magnetoresistive head in which a reproducing element having a magnetoresistive effect is provided between two shields via an insulating film, at least one of an electrode film for leading a current to the reproducing element is provided. And a magnetic head electrically connected to the shield via a fuse to be blown. 2. A magnetoresistive head in which a reproducing element having a magnetoresistive effect is provided between two shields via an insulating film, wherein at least one of the electrode films for guiding a current to the reproducing element is provided. A magnetoresistive magnetic head having a structure electrically connected to said shield via a fuse to be blown, wherein said fuse has a residual mark that has been blown. head. 3. The apparatus has at least four or more electrode pads in order to externally supply current to a reproducing element or a recording element.
A magneto-resistive magnetic head, wherein a fuse connected to the two electrode pads is blown by applying a current or a voltage between at least two of the electrode pads. 4. A device having at least four or more electrode pads for supplying a current to a reproducing element or a recording element from the outside,
A magnetoresistive effect type magnetic head capable of blowing a fuse connected to the two electrode pads by applying a current or a voltage between at least two of the electrode pads; Characterized by having a fusing residue. 5. In order to externally supply current to a reproducing element or a recording element, at least four or more electrode pads are provided.
At least two or more of the four or more electrode pads are connected to a reproducing element, and a current or a voltage is applied between at least two of the electrode pads, so that the two electrode pads are A magnetoresistance effect type magnetic head, wherein a connected fuse is blown. 6. It has at least four or more electrode pads in order to externally supply current to a reproducing element or a recording element,
A method of manufacturing a magnetoresistive head in which a fuse connected to the two electrode pads is blown by applying a current or a voltage between at least two of the electrode pads. Blowing the fuse using a current pulse or a voltage pulse after the process of manufacturing the magnetic head or after the manufacturing process is completed,
A method for manufacturing a magnetoresistive magnetic head, further comprising inspecting a short circuit or a dielectric strength between the reproducing element and the shield. 7. A structure in which a reproducing element having a magnetoresistance effect is provided between two shields via an insulating film,
A method for manufacturing a magneto-resistance effect type magnetic head having a structure in which at least one of an electrode film for guiding a current to the read element is electrically connected to the shield via a fuse that blows, The method is characterized in that the fuse is blown using a current pulse or a voltage pulse during the process of manufacturing the effect type magnetic head or after the manufacturing process is completed, and thereafter, a short circuit or a withstand voltage between the reproducing element and the shield is inspected. Of manufacturing a magnetoresistive magnetic head. 8. A device having at least four or more electrode pads for externally supplying current to a reproducing element or a recording element,
By applying a current or voltage between at least two of the electrode pads, it is possible to blow a fuse connected to the two electrode pads,
What is claimed is: 1. A method for manufacturing a magneto-resistance effect type magnetic head, comprising: a step of manufacturing a magneto-resistance effect type magnetic head; And fusing the fuse, and then inspecting for a short circuit or dielectric strength between the read element and the shield. 9. The method for manufacturing a magnetoresistive head according to claim 1, wherein the fuse is blown by irradiating the fuse with a laser. Manufacturing method.