JPS6364614A - Multi-element thin film magnetic head and its driving circuit - Google Patents

Abstract

PURPOSE:To reduce the number of terminals without harming the function of a multi-element thin film magnetic head by connecting single thin film magnetic head element to a pair of terminals selected from each set out of two sets of common terminal groups, product of number of terminals of which becomes the number of thin film magnetic head elements. CONSTITUTION:A lower insulating layer 13 is formed on a ceramic substrate 12, and a film of lower magnetic layer 14 is formed on it, and worked to specified form by ion etching method. Then, a gap layer 15 is formed and the first wiring pattern 9 is formed. Then, a level difference eliminating layer 16 is coated and baked for pattern making. Then, the film of upper magnetic layer 17 is formed and worked. An insulating layer 18 for the pattern 9 is formed and the second wiring pattern 10 is formed. After removing insulating layers 18, 19, a wiring pattern 11 is formed, and a protective film 20 is provided to obtain a thin film magnetic head. In an example shown in the figure, product of number of terminals of common terminals A, B becomes 20, and twenty thin film magnetic elements can be driven independently.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multi-element thin film magnetic head used in fixed magnetic disk drives, flexible magnetic disk drives, and magnetic tape drives.

[Conventional technology]

Thin-film magnetic heads are easier to mass produce than conventional ferrite bulk heads, have low inductance and can operate at high speeds, and are easy to miniaturize and refine shapes such as gap length and track width. For this reason, it has been put into practical use as a head for large-capacity fixed magnetic disk drives aimed at high transfer speeds and high recording densities. In addition, active development is being carried out with the aim of increasing the reproduction sensitivity by increasing the number of coil turns and employing a magnetoresistive element, which can be installed in small magnetic disk drives.

Another feature of thin-film magnetic heads is that multiple elements can be formed on one substrate, and this can be used to create multi-element thin-film magnetic heads in which multiple thin-film magnetic rad sliders are fabricated on one slider. However, consideration is being made. In this multi-element thin film magnetic head, multiple tracks can be accessed on one slider without a seek operation, so high-speed access is possible and the throughput of the storage device is dramatically increased. Furthermore, if all tracks on a magnetic recording medium can be covered by a multi-element thin film magnetic head with one slider or multiple sliders, the magnetic recording system will no longer require a slider seek mechanism, making the system smaller and lighter. It is possible to realize lower prices.

[Problem that the invention seeks to solve]

To drive a multi-element thin film magnetic head, two or three terminals are required for each element. In order to operate each element independently, at least one independent terminal is required for each element, and even if the other terminal is shared, the total number of terminals of a multi-element thin film magnetic head is number + 1) or more. That is, if there are 100 elements, 101 or more terminals are required.

Soldering or thermocompression bonding is typically used to connect the terminals of the thin-film magnetic head to the drive circuit, but as the number of connection points increases, reliability with respect to disconnections or contact failures is greatly reduced. Furthermore, if the number of wires used for connection is large, there will be significant restrictions on the method of attaching the head.

Furthermore, in current magnetic recording systems, the track width for recording information is about 10-10 microns to several tens of microns, and it is quite difficult to keep the width of each thin-film magnetic head element within this range. Therefore, in order to secure the area for the terminals, the area of the entire multi-element thin film magnetic head chip becomes significantly larger than that of each thin film magnetic head element.

In other words, the terminals occupy almost the majority of the area of the substrate on which the multi-element thin film magnetic head is fabricated, which not only increases manufacturing costs but also makes the completed head chip larger than necessary. This poses a major constraint on the method.

As described above, in a multi-element thin film magnetic head, a large number of terminals not only reduces reliability, but also increases manufacturing costs and imposes significant restrictions on handling.

An object of the present invention is to provide a thin film magnetic head with a significantly reduced number of terminals without impairing the functions of the multi-element thin film magnetic head.

[Means for solving problems]

The structure of the multi-element thin film magnetic head of the first invention has two sets of common terminals whose product of the number of terminals is the number of thin film magnetic head elements, one from each of the two sets of common terminals. The present invention is characterized in that a single thin film magnetic head element is connected to a selected pair of terminals.

The configuration of the drive circuit for a multi-element thin film magnetic head according to the second invention has two sets of common terminals whose product of the number of terminals is the number of thin film magnetic head elements, and from each set of the two sets of common terminals. A terminal switching signal for selecting a terminal by switching one terminal from each of the two sets of common terminals of a multi-element thin film magnetic head in which a single thin film magnetic head element is connected to each terminal pair selected one by one. a terminal selection section for switching the two terminals connected to the recording/reproducing channel according to the terminal switching signal; a recording section for recording to the two terminals;
The apparatus is characterized in that it includes a reproducing section that performs reproduction on the terminals, and a recording/reproduction switching section that switches the two terminals to the recording section and the reproducing section.

[Effect]

A multi-element thin film magnetic head used in a fixed magnetic disk device or a flexible magnetic disk device does not necessarily need to drive a plurality of elements at the same time. Generally, in a fixed magnetic disk device or a flexible magnetic disk device, 8-bit parallel data is converted from parallel to serial and continuously recorded on one track. Therefore, when one thin film magnetic head element is recording or reproducing data, there is no need for other elements to operate simultaneously. On the other hand, in magnetic tape devices, 8-bit or 16-bit data is input to the magnetic head in parallel and recorded and played back at the same time, so in the multi-element magnetic head used in magnetic tape devices, all the elements are They are required to operate simultaneously. In such applications, at least one independent terminal is required for each magnetic head element.

On the other hand, in multi-element thin film magnetic heads used in fixed magnetic disk drives and flexible magnetic disk drives, it is not necessary to operate all the elements simultaneously, and therefore independent terminals are not necessarily required for each element.

In consideration of the above points, the present invention makes it possible to obtain a multi-element thin film magnetic head and its drive circuit which have the same functions as the original multi-element magnetic head even if the number of terminals is reduced.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a plan view showing wiring patterns of a multi-element thin film magnetic head according to an embodiment of the first invention, in which 9 is a first layer wiring pattern, 10 is a second layer wiring pattern, and 11 is a third layer wiring pattern. It's a pattern.

FIG. 2 is a cross-sectional view of one element of the multi-element drop magnetic head according to the first invention, in which 12 is a substrate, 13 is a lower insulating layer, 1
4 is a lower magnetic layer, 15 is a gap layer, 16 is a step elimination layer, 17 is an upper magnetic layer, IS is an upper first insulating layer, 1 is an upper second insulating layer, and 20 is a protective layer.

The method for manufacturing the multi-element thin film magnetic head of this embodiment will be briefly explained with reference to FIGS. 1 and 2. First, 2□0. The lower insulating layer 13 of the film was formed to a thickness of 3 μrn by sputtering. Next, a NiFe film lower magnetic layer 14 was formed to a thickness of 3 μm using the wafer etch method, and processed into a predetermined shape using photolithography and ion etching. Next, A! ! The gap layer 15 of the 203 film was formed to a thickness of 0.4 μm by sputtering.
Further, a first layer wiring pattern 9 of a Cu film was formed by frame plating using a resist frame.

In FIG. 1, the first layer wiring pattern 9 near the lower magnetic layer 14 and the upper magnetic layer 17 is shown in a simplified manner, but as shown in FIG. 2, it is a five-turn coil. Next, in order to flatten the step caused by the coil, a step eliminating layer 16 using photoresist was applied, patterned, and fired. Thereafter, a NiFe film upper magnetic layer 17 was formed to a thickness of 3 μm by sputtering and processed using photolithography and ion etching. next,
As the upper first insulating layer 18 for the first layer wiring pattern 9, AJ? □0. A film with a thickness of 1 μm is formed by sputtering, and a Cu film is formed as a second layer wiring pattern 1o by plating using a resist frame, and then a second insulating layer 19 on top of the ^e203 film is formed by sputtering. A film with a thickness of 1 μm was formed.

Further, by using photolithography technology and chemical engineering/sotching technology, the upper first insulating layer 18 and the upper second insulating layer 18 of the connection portion between the first layer wiring pattern 9 and the second layer wiring pattern 10 are
After removing the insulating layer 19, the third wiring pattern 1 of the Cu film is removed.
1 was formed by a frame plating method using a resist frame. On top of that, people! A protective layer 20 of 203 film was formed to a thickness of 30 μm using a sputtering method, and then surface polishing was performed to complete a thin film magnetic head element.

In addition, in the above manufacturing method, ferrite can be used as the substrate 12 in addition to ceramic, and the lower magnetic layer 1
4 and the upper magnetic layer 17, a thin Co-based amorphous soft magnetic film of NiFe or a sendust film can be used. Furthermore, 5102PA can be used in addition to the 147203 film as the lower insulating layer 13, the gap layer 15, the upper first insulating layer 18, the upper second insulating layer 19 and the protective layer 20, and as the wiring patterns 9, 10 and 11. Cu
Other than 1il! A film or an Au film can be used. Further, as a film forming method, in addition to sputtering and plating, ion beam sputtering and vapor deposition can be used.

In this example, an example was shown in which the second wiring pattern 10 and the third wiring pattern 11 were formed after forming the upper magnetic layer 17 as a manufacturing procedure. It is also possible to reverse the procedure. For example, the coil can be made into two layers, the lower layer coil being made using the first wiring pattern 9, the upper layer coil being made using the third wiring pattern 11, and then the upper magnetic layer 17 can be made.

Next, a driving circuit for a multi-element thin film magnetic head according to a second invention will be explained.

FIG. 3 is a wiring diagram showing a method for selecting elements of a multi-element thin film magnetic head according to the second invention, in which 1 is a magnetic core, 2 is a wiring pattern, and A, . . . are terminals of common terminal group A. The number, B1...Bo is the terminal number of the common terminal group B, Sl...
-S is the element number of the thin film magnetic head.

In FIG. 3, the terminals of the multi-element thin film magnetic head are roughly divided into a common terminal group A and a common terminal group B. Each of the common terminal group A and the common terminal group B is a set of a plurality of terminals, and a single thin film magnetic head element is connected to a pair of terminals selected from each common terminal group. For example, set the terminal numbers of common terminal groups A and B to Ak
and Bk (k=1.2, 3.-n), and if the terminal pair is expressed in the form (Ak, Bk), then the terminal pair (A1゜B
+), the thin film magnetic head element S1 is connected to the
A thin film magnetic head element S2 is connected to the terminal pair (AI, B2). Therefore, since a single thin film magnetic head element corresponds to a single terminal pair, by selecting a single terminal pair, a single thin film magnetic head element can be translated into two.

Furthermore, if the number of terminals in common terminal groups A and B is n each, the total number of terminal pairs is 02, so the number of thin film magnetic head elements that is the product of the number of terminals in common terminal groups A and B is driven. be able to.

In the case of FIG. 1, the product of the number of terminals is the number of thin-film magnetic head elements. Common terminal group A (having 5 terminals A, ~A), common terminal group B (having 4 terminals B, ~B4, By selecting one terminal from each common terminal group, a total of 20
Each thin-film magnetic head element can be driven independently. For example, when driving the single-film magnetic head element S1, terminal A1 and terminal B may be selected, and when driving thin-film magnetic head element S20, terminal A5 and terminal B4 may be selected.

That is, in the multi-element thin film magnetic head according to this embodiment, as shown in FIG. 1, 20 thin film magnetic head elements can be driven independently with nine terminals, so the number of terminals obtained by the conventional method is 21. We were able to reduce the number of terminals by more than half compared to the previous version.

Therefore, the chip area of the multi-element thin film magnetic head can be significantly reduced, mass productivity is improved, and the reliability of terminal connections is improved due to the reduction in the number of terminals, and restrictions on mounting methods are eliminated.

Select a single terminal pair from common terminal groups A and B,
In order to operate the thin film magnetic head element independently, the terminals other than the selected terminal pair must be placed in an oven state in terms of the electrical circuit.

FIG. 11 shows a block diagram of a multi-element J-film magnetic head drive circuit for driving a multi-element thin film magnetic head according to the second invention, in which 3 is a terminal selection section, 4 is a reproduction section, 5 is a recording section, 6 is a recording/reproduction switching section, 7 is a terminal switching section A, 8 is a terminal switching section B, 101 is a terminal selection signal, 10.2 is reproduction data, 103 is recording data, 104 is a terminal switching signal, 105
is a reproduction signal, and 106 is a recording signal.

In FIG. 4, recording data 103 to recording signal 106
The recording unit 5 that generates the signal and the reproducing unit 4 that extracts the reproduced data 102 from the reproduced signal 105 are connected to both the terminal switching unit (A) 7 and the terminal switching unit (B) 8 via the recording/reproducing switching unit 6. There is. The terminal selection section 3 sends a terminal switching signal 104 to the terminal switching section (A) 7 and the terminal switching section (B) 8 in accordance with the terminal selection signal 101. The terminal switching unit (A) 7 and the terminal switching unit (B) 8 select one terminal each from the common terminal group (A) 7 and the common terminal group (B) 8 according to the terminal switching signal 104, and perform recording/recording. Connect to the regeneration switching section and electrically open the other terminals. Through the above processing, a single thin film magnetic head element is connected to the reproducing section 4 or the recording section 5.

FIG. 5 is a circuit diagram showing an embodiment of the multi-element thin film magnetic head drive circuit according to the second invention, in which 21 is a flip-flop, 22 is an amplifier, 23 is a comparator, 24 and 25 are current sources, and 26, 27 .28 and 29 are analog switches, 30 and 31 are decoders, 1'07 is a recording/reproduction switching signal, and 108 and 109 are power supplies.

In FIG. 5, during recording, by shorting the analog switch 26 and opening the analog switch 27,
Only the recording section 5 is connected to the terminal switching section 7.

The record data 103 inverts the flip-flop 21, and the transistors TR1 and TR2 are alternately switched, so that the currents of the current sources 24 and 25 are alternately supplied to the terminals.

During reproduction, the analog switch 27 is short-circuited, the analog switch 26 is opened, and only the reproduction section 4 is connected to the terminal switching sections 7 and 8. The reproduced signal 105 is amplified by an amplifier 22, differentiated by a differentiating circuit using a capacitor C and a resistor R, and pulsed by a comparator 23.

In addition, the terminal selection signal 101 is set so that the upper 4 bits and lower 4 bits of the terminal selection signal 101 given from the 8-bit parallel bus are information on the terminals to be selected in the common terminal groups A and B, respectively. The 4 bits and the lower 4 bits are input to decoders 30 and 31. The decoders 30 and 31 send a terminal switching signal to the analog switches 28 and 29 to connect only one terminal to the recording section 5 or the reproducing section 4 and open the other terminals according to the terminal selection signal 101. 104 is output. Analog switches 28 and 29 connect one terminal each from common terminal groups A and B to recording section 5 or reproducing section 4.

By using the multi-element thin film magnetic head drive circuit according to the present invention, the product of the numbers of terminals of common terminal groups A and B can be obtained by combining the data of the upper 4 bits and the lower 4 bits of the terminal selection signal 101, that is, as shown in FIG. In this case, 20 terminal pairs can be selected.

Furthermore, since the terminals other than the selected terminal pair become electrical ovens, there is no leakage or mixing of data between different tracks, and highly reliable recording and reproducing operations can be performed.

FIG. 6 is a circuit diagram showing an embodiment of a multi-element thin film magnetic head drive circuit when a magnetoresistive element is used as the thin film magnetic head element, and 32 is a current source that supplies a sense current to the magnetoresistive element. The transistors composing the rl
, r3 is a current setting resistor, and 110 is a power supply.

The magnetoresistive element connected to the multi-element thin film magnetic head drive circuit shown in FIG. 6 has a three-terminal configuration, and the central terminal is commonly connected to the ground.

Also, a terminal selection signal 10 is selected from among the common terminal groups A and B.
1, current source transistor 32 is turned on by the outputs of decoders 30 and 31, and a sense current is supplied to the terminal pair selected by No. 1. Then, the reproduction section 4 amplifies, differentiates and pulses the reproduced signal voltage 1.5 generated by the magnetoresistive effect in the pair of terminals to which the sense current is supplied.

As described above, the multi-element thin film magnetic head and multi-element thin film magnetic head drive circuit according to the present invention can be applied even when the thin film magnetic head element is a magnetoresistive element or when the number of terminals of the element is three.

〔Effect of the invention〕

As described above, by using the multi-element thin film magnetic head and its drive circuit according to the present invention, each thin film magnetic head element can be driven independently with fewer terminals than the conventional method, reducing the number of terminal connections and head chip area. At the same time, the slider mounting method can be reduced and the flexibility of the slider mounting method improved. Furthermore, the number of terminals that can be reduced by the present invention increases as the number of elements increases, so it is inherently superior in mass productivity and reliability.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the wiring pattern of a multi-element thin film magnetic head according to the present invention, FIG. 2 is a cross-sectional view of one element of a multi-element single-film magnetic head according to the present invention, and FIG. 4 is a block diagram of a multi-element thin-film magnetic head drive circuit according to the present invention; FIG. 5 is a circuit diagram of a multi-element thin-film magnetic head drive circuit according to the present invention; FIG. 6 is a circuit diagram of a multi-element thin film magnetic head drive circuit using magnetoresistive elements. l...Magnetic core, 2...Wiring pattern, 3...Terminal selection section, 4...Reproducing section, 5...Recording section, 6...
Recording/reproduction switching section, 7, 8...terminal switching section, 9.10.
11... Wiring pattern, 12... Board, 13.18
．． 19... Insulating layer, 14.17... Magnetic layer, 15.
. . . Gap layer, 16 . . . Step-difference eliminating layer, 20 . . . Protective layer, 21 .
26.27, 28.29...analog switch, 30.
31... Decoder, 32... Current source transistor,
A1 to A, B, to Bn terminal number, 81 to S,...element number, 101...terminal selection signal, 102...playback data, 103...recording data, 104...terminal switching Signal, 105... Reproduction signal, 106... Recording signal, 107... Recording/reproduction switching signal, 108, 109, 1
10...Power supply. Spear / Mei 2 Mouth 3rd Ward Me 4 Spear 51!4

Claims (1)

[Claims] 1) For a terminal pair having two sets of common terminals whose product of the number of terminals is the number of thin-film magnetic head elements, and one terminal selected from each set of the two sets of common terminals, A multi-element thin film magnetic head characterized in that a single thin film magnetic head element is connected. 2) It has two sets of common terminals where the product of the number of terminals is the number of thin-film magnetic head elements, and a single thin-film magnetic head element is attached to each pair of terminals, one selected from each of the two sets of common terminals. a terminal selection unit that generates a terminal switching signal for selecting a terminal by switching one terminal from each of the two sets of common terminal groups of the multi-element thin film magnetic head to which the multi-element thin film magnetic head is connected; and a recording/reproducing channel according to the terminal switching signal. a terminal switching section for switching two terminals connected to the terminal; a recording section for recording to the two terminals; a reproducing section for reproducing data for the two terminals; 1. A drive circuit for a multi-element thin-film magnetic head, comprising a recording/reproduction switching section for switching.