JPH06349028A - Magneto-resistance effect type head and its production - Google Patents

Abstract

PURPOSE:To provide the magneto-resistance effect type head which has high reliability and with which high output is stably obtainable and the process for production of this head. CONSTITUTION:This magneto-resistance effect type head is formed by laminating magneto-resistance effect element parts 12, a lead layer 14, a lower lead gap layer 11, an upper lead gap layer 15, a lower shielding layer 10, an upper shielding layer 16, etc., on a ceramic substrate 8. This process is for production of such head. The head described above is provided with electron cooling elements near the magneto-resistance effect element parts 12. As a result, the increase in the thermal noise generated by generation of heat in the magneto- resistance effect element parts 12, the unstability of exchange biases and the destruction of the elements by an abnormal resistance increase are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive head having particularly high output and high reliability, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As the performance of magnetic disk devices increases, the thin film magnetic heads used therein are required to have various performances. One of them is the use of a magnetoresistive head. Since the output of the magnetoresistive head does not depend on the peripheral speed, it has a great effect on increasing the capacity of the small-diameter disk device, but it still has many technical problems in practice. In particular, regarding a narrow track head in which the advantages of the magnetoresistive head are greatly exerted, if the height of the magnetoresistive element is reduced or the current supplied thereto is increased in order to increase the output, the electric resistance or There is a problem that the influence of thermal noise becomes remarkable due to the increase in current, and as a worse state, abnormal heat generation causes melting of the element.

The structure of a magnetoresistive head for a hard disk drive manufactured by the conventional technique will be described below with reference to FIGS. 2, 3 and 4. FIG. 2 is a perspective view of the magnetoresistive head viewed from the medium facing surface, and FIG. 3 is an enlarged view of the element portion. Since the magnetoresistive head is a read-only head, it is usually used in an integrated form with the recording inductive head. Therefore, the description will be given below including the recording head.

The magnetoresistive head is used in the state in which elements are formed on a ceramic substrate by using a thin film forming technique and the slider 1 for a magnetic disk device as shown in FIG. 2 is used. When the head is mounted on the apparatus, a gimbal is adhered to the floating rail 2 in parallel with the back surface side and used as a magnetic head assembly state. The levitation rail 2 takes various forms depending on the application, and two or three rails are formed by machining or ion beam etching.

FIG. 2 shows the shape of three rails formed by machining. The magnetoresistive head element is formed on the front side of the slider 1 in the figure, and on the rear end surface in the rotational direction of the medium during operation.
Is an upper magnetic layer, 5 is a terminal, and 6 is a pad for bonding a wire later. Here, there are four terminals 5 and four pads 6, respectively, which means that at least two terminals 5 are required for each of the recording section and the reproducing section. FIG. 3 is an enlarged view of the magnetoresistive head element part shown by A in FIG. Reference numeral 7 is a back gap portion where the upper and lower magnetic layers of the recording head are joined.

FIG. 4 shows a portion B where the magnetoresistive head element portion in FIG. 3 faces the medium. This one is
First, a lower shield layer 10 is formed of permalloy, sendust, or an iron-based alloy material formed by electroplating or sputtering on a ceramic substrate 8 coated with an insulator 9 such as alumina formed by sputtering. A lower read gap layer 11 made of an insulating material such as alumina is formed by sputtering, and a magnetoresistive effect element portion 12 is further laminated thereon. Although the magnetoresistive effect element portion 12 is shown as a single layer in the figure, it has a two- to four-layered structure depending on the bias system used for driving the magnetoresistive effect element. Titanium, SAL (Soft
With Adjacent Layer bias, three layers of permalloy (magnetoresistive effect film) and spacers such as tantalum and SAL film in which a third element such as rhodium is added to iron and nickel are added, and when an exchange bias is applied to the magnetoresistive effect film, it is magnetic. An antiferromagnetic film, which is an alloy of iron and manganese, is laminated and used so as to be in direct contact with the resistance effect film.

Next, a low resistance material such as gold, a lead layer 14 formed by using an adhesion strengthening layer such as chromium or titanium for strengthening adhesion between gold and each layer above and below, and an insulating material such as alumina. The upper read gap layer 15 and the upper shield layer 16 formed of permalloy or iron-based alloy formed by the electroplating method or the sputtering method are sequentially laminated to complete the production of the reproducing head portion.

Next, in forming the recording head portion, first, the lower magnetic layer 17 of the recording portion is formed on the upper shield layer 16 by electroplating or the like. Here, in order to prevent magnetic coupling between the upper shield layer 16 and the lower magnetic layer 17, a separation layer made of an insulating material such as alumina may be inserted between the two layers. Next, after laminating the gap layer 18 of the recording portion, although not shown in the drawing, a lower insulating layer made of a resin such as a novolac resin or a polyimide resin, a lower coil layer formed by an electroplating method, and a lower insulating layer are formed. Similarly, an upper insulating layer is sequentially laminated, an upper magnetic layer 19 is laminated by an electroplating method or the like, and finally a protective layer 20 made of alumina or the like is used as a protective layer to complete the production of the magnetoresistive head.

[0009]

The problems of the prior art will be described below with reference to FIGS. FIG. 5 shows a plan view of the magnetoresistive effect element portion. In the figure, 21 is a magnetoresistive effect element, and 22 is a lead layer. Since the magnetoresistive effect element 21 is a magnetic flux response type reproducing head, a reproduction output independent of the speed of the medium can be obtained. The smaller the height H of the magnetoresistive effect element 21 and the thinner the film thickness t, the output. growing. Normally, the width L and the film thickness T of the lead layer 22 are larger than the height (width) H and the film thickness t of the magnetoresistive effect element 21, L is several tens of μm, and T is 1000 to 2000 angstroms and H is 1 to. 3 μm, t is 500 including bias layer
It is 1000 angstroms. Therefore, it is understood that the region of the magnetoresistive head having the highest electric resistance is the magnetoresistive effect element 21 due to its structure.

As described above, the magnetoresistive effect element 21 is originally used.
However, if the height H of the magnetoresistive effect element 21 is decreased or the film thickness t is decreased in order to improve the reproduction output, the electric resistance of the magnetoresistive effect element 21 increases more and more. I will end up. When driving a magnetoresistive head, a certain amount of direct current ionization is applied to the element part. However, if the electric resistance of the element part increases, its temperature increases in proportion to the product of the square of the resistance value and the current value. As shown in FIG. 6, the element temperature rapidly rises as the element resistance increases. However, as the temperature of the element rises, the influence of thermal noise on the reproduced signal becomes remarkable, and when the exchange bias is used, the antiferromagnetic film is thermally unstable, which causes the bias instability. Barkhausen noise is generated.

When the element temperature further rises, the element is in a state of fusing and breaking, and the function as a magnetic head is not fulfilled. In FIG. W. The dimension shown by is the track width of the magnetoresistive head, but if this dimension is reduced to improve the track density, the electrical resistance of the element part decreases, but the output also decreases, so to improve the output It is necessary to increase the direct current flowing through the element. Also at this time, since the element temperature rises,
Various problems similar to the above-mentioned phenomenon occur.

The conventional magnetoresistive head described above is
When the height H of the magnetoresistive effect element 21 is decreased or the film thickness t is decreased for the purpose of improving the reproduction output, the element resistance increases, so that the element temperature rapidly increases and the thermal noise of the reproduction signal is increased. However, there is a problem in that the increase, instability of the exchange bias, and the fusing of the element due to abnormal heat generation occur. In addition, the track width T. W. There is a similar problem when the current applied to the device is increased in order to reduce the voltage and obtain a high output.

The present invention solves such a problem, and an object of the present invention is to provide a magnetoresistive head capable of obtaining a stable reproduction signal with high output and a method for manufacturing the same.

[0014]

For this reason, the magnetoresistive head of the present invention is provided with an electronic cooling element near the magnetoresistive element.

[0015]

According to the above structure, the heat generated by the increased resistance of the magnetoresistive effect element can be absorbed and cooled by the electronic cooling element. Therefore, it is possible to prevent an increase in thermal noise caused by heat generation of the magnetoresistive effect element, instability of the exchange bias, and further, destruction of the element due to an abnormal increase in resistance.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an enlarged cross-sectional view of the element portion of a magnetoresistive head according to an embodiment of the present invention as seen from the medium facing surface. Since the completed state of the magnetoresistive head is the same as that of the conventional example, description thereof will be omitted.

First, an electronic cooling element is formed on a ceramic substrate 8 covered with an insulator 9 such as alumina formed by a sputtering method. The electronic cooling element is formed by using an N-type semiconductor 23, for example, using a material obtained by adding a small amount of selenium to an alloy of bismuth and tellurium, and then using a P-type semiconductor 24 by using a material obtained by adding a small amount of antimony to an alloy of bismuth and tellurium. To form. Further, a bridge portion 25a and a lead portion 25b for electrically connecting the N-type semiconductor 23 and the P-type semiconductor 24 are formed by using a low resistance material such as copper or gold,
Obtain an electronic cooling element. If the electronic cooling element is operated so that current flows from the N-type semiconductor 23 to the P-type semiconductor 24 through the bridge portion 25a, the bridge portion 25a serves as a cooling contact. The lead part 25b of the electronic cooling element for extracting electrodes from the N-type semiconductor 23 and the P-type semiconductor 24 to the outside and the contact point of each of the N-type semiconductor 23 and the P-type semiconductor 24 serve as a heating contact point. There is no particular problem as long as it is charged and separated to a position where it is not affected by heat.

Next, in order to prevent the electronic cooling element from being electrically connected to the upper layer, the insulating layer 26 is formed by the sputtering method using an insulating material such as alumina. Next, the lower shield layer 1 is made of permalloy, sendust, or an iron-based alloy material formed by electroplating or sputtering.
Form 0. Next, the lower read gap layer 11 made of an insulating material such as alumina formed by the sputtering method is formed, and the magnetoresistive effect element portion 12 is sequentially laminated thereon. Although the magnetoresistive effect element portion 12 is shown as a single layer in the figure, it has a two- to four-layered structure depending on the bias system used for driving the magnetoresistive effect element portion, and the details are as described in the conventional example.

Next, a lead layer 14 formed of a low resistance material such as gold, an upper lead gap layer 15 formed of an insulating material such as alumina, a permalloy or an iron-based alloy formed by electroplating or sputtering is used. The upper shield layer 16 thus formed is sequentially laminated to complete the production of the reproducing head portion. When the exchange bias is used, an alloy of iron and manganese is formed on the magnetoresistive effect film so as to be in direct contact with the magnetoresistive effect film or on the lowermost part of the lead layer 14. Next, the creation of the recording unit will be omitted because it is similar to the conventional example.

In the magnetoresistive effect head formed as described above, the amount of heat generated increases as the current flowing through the magnetoresistive effect element section 12 and the electric resistance of the magnetoresistive effect element section 12 increase during head operation. Since the electronic cooling element is forcibly cooled, the influence of thermal noise on the reproduction signal can be mitigated, the stability of the exchange bias can be increased, and the element can be prevented from being destroyed. To achieve this effect, when increasing the track density, measures such as thinning the magnetoresistive film, lowering the height of the magnetoresistive element, and increasing the current applied to the magnetoresistive element were taken. In this case, it will be particularly effective.

In the above embodiment, the structure in which the electronic cooling element is provided under the lower shield layer 10 is shown. However, in order to obtain the same effect as in the above embodiment, the electron is placed on the upper shield layer 16 through the insulating layer 26. A cooling element may be provided. Further, in order to further enhance the effect of the electronic cooling element, the lower shield layer 1
It is also possible to provide it between 0 and the lower read gap layer 11 or between the upper read gap layer 15 and the upper shield layer 16. Further, in order to simplify the steps and layers, the N-type semiconductor and the P-type semiconductor are directly connected to the lower shield layer 10 or the upper shield layer 16, and the upper shield layer 1
6 or the lower shield layer 10 can also be used as a cooling point. As another method, a layer serving as a cooling point is brought into direct contact with the magnetoresistive effect element section 12, and the N-type semiconductor 23 and the P-type semiconductor 24 are used in a part of the lead layer 14 of the magnetoresistive effect element section 12. A method of forming an electronic cooling element by bringing it into contact with a layer serving as a cooling point and using the layer serving as a cooling point as a shunt bias layer, and a magnetoresistive effect element section 12
On the part of the lead layer 14 that contacts the N-type semiconductor 23 and P
The magnetoresistive effect element portion 12 itself may be used as a cooling point by using the type semiconductor 24. Further, although FIG. 1 shows a state where the electronic cooling element portion is exposed on the surface, it is not always necessary to expose it on the surface as long as the effect of the present invention can be obtained.

[0023]

As described above, according to the present invention, the heat generated by the increase in the resistance of the magnetoresistive effect element can be absorbed and cooled by the electronic cooling element, so that the thermal noise generated by the heat generation of the magnetoresistive effect element and the exchange bias are increased. Instability of
Further, it is possible to prevent the device from being broken due to an abnormal increase in resistance.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of an element portion of a magnetoresistive head according to an embodiment of the present invention viewed from a medium facing surface.

FIG. 2 is a perspective view of a conventional magnetoresistive head when viewed from the medium facing surface.

FIG. 3 is an enlarged view of an element portion of a conventional magnetoresistive head.

FIG. 4 is an enlarged sectional view of an element portion of a conventional magnetoresistive head.

FIG. 5 is a plan view of an element portion of a conventional magnetoresistive head.

FIG. 6 is a relational diagram of element resistance and element temperature of a conventional magnetoresistive head.

[Explanation of symbols]

 8 Ceramic Substrate 9 Insulator 10 Lower Shield Layer 11 Lower Lead Gap Layer 12 Magnetoresistive Element 14 Lead Layer 15 Upper Lead Gap Layer 23 N-type Semiconductor 24 P-type Semiconductor 25a Bridge 25b Lead

Claims (6)

[Claims] 1. A magnetoresistive effect element, a lead layer connected to the magnetoresistive effect element, an upper read gap layer and a lower read gap layer for insulating the magnetoresistive effect element and the lead layer from a surrounding metal film. A magnetoresistive head having an upper shield layer and a lower shield layer in contact with the upper read gap layer and the lower read gap layer, wherein an electronic cooling element is provided in the vicinity of the magnetoresistive element. And a magnetoresistive head. 2. The magnetoresistive head according to claim 1, wherein a part of the upper shield layer or the lower shield layer is used as a cooling point of the electronic cooling element. 3. The magnetic element according to claim 1, wherein the electronic cooling element is provided between the magnetoresistive effect element and the upper shield layer, or between the magnetoresistive effect element and the lower shield layer. Resistance effect type head. 4. The layer in contact with the magnetoresistive effect element is used as a cooling point of the electronic cooling element.
The magnetoresistive head described. 5. The magnetoresistive head according to claim 1, wherein the magnetoresistive effect element is used at a cooling point of the electronic cooling element. 6. A thermoelectric cooler is formed on a substrate covered with an inorganic insulating material, and then a lower shield layer, a lower read gap layer, a magnetoresistive effect element, a lead layer, an upper read gap layer is formed through an insulating layer. A method of manufacturing a magnetoresistive head, comprising forming an upper shield layer in order.