JP2000113438A - Magnetic disk device and suspension - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk device which can realize high frequency wave recording operation of approximately 150 MHz or more. SOLUTION: In this device, a pair of conductive wirings 112-1, 112-2 for transmitting a recording signal to a magnetic head 12 and/or supplying electric power is provided on a suspension 103 of supporting the magnetic head 12 and this suspension 103 is made in an insulation state for all electric circuits constituting this device. Further, an opening part 115 is provided along the longitudinal direction of the suspension 103, and the pair of the conductive wirings may be positioned holding the opening part 115 between them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive used in an electronic computer, an information processing apparatus, and the like, and a suspension for a magnetic head used in the magnetic disk drive.

[0002]

2. Description of the Related Art A semiconductor memory and a magnetic memory are mainly used as storage devices of information equipment. A semiconductor memory is used for an internal storage device from the viewpoint of access time, and a magnetic memory is used for an external recording device from a viewpoint of large capacity and non-volatility. The mainstream of magnetic memories are magnetic disks and magnetic tapes. Many of the recording media used for these devices have a magnetic thin film formed on a tape made of a substrate or resin such as Al. In order to write magnetic information on these recording media, a functional unit having an electromagnetic conversion function is used. Also, in order to reproduce magnetic information, the magnetoresistance effect,
A functional unit utilizing a phenomenon such as a giant magnetoresistance effect or electromagnetic induction is used. These functional units are provided in an input / output component called a magnetic head.

FIGS. 3A and 3B are a plan view and a cross-sectional view showing the basic structure of a magnetic disk drive. Below the recording medium 11-1 shown in FIG. 3A, there are a plurality of recording media 11-2 to 11-4 as shown in FIG. The magnetic head 12 can move on the surface of the recording medium. Suspension 1
Reference numeral 03 has a function of pressing the magnetic head 12 against a recording medium with a predetermined load. The magnetic head is a suspension 1
03, rotary actuator 1 via arm 101
3 supported. A predetermined electric circuit is required for processing of a reproduction signal and input / output of information.
Attached to. Write signal to the magnetic head,
The wiring 15 for transmitting a read signal from the magnetic head is
It is connected to the read / write IC 14.

[0004] The magnetic head moves on the surface of the recording medium and, after being positioned at an arbitrary position, writes or reads information. An electric circuit for controlling this also exists together with the electric circuit for signal processing.

FIG. 6 is a schematic view of a magnetic head element partially cut away. The writing function unit 21 includes the spiral coil 2
6 and a magnetic pole 27 and a magnetic pole 28 which wrap it up and down and are magnetically coupled. The magnetic pole 27 and the magnetic pole 28 are both formed of a magnetic film pattern.

The reproducing function unit 22 includes a magnetoresistive element 23
And an electrode 29 for supplying a constant current to this element and detecting a resistance change. The magnetic pole 28 between the writing function unit 21 and the reproduction function unit 22 also functions as a shield during reproduction. The magnetic film 25 functions as a shield together with the magnetic pole 28 during reproduction. These functional parts are
It is formed on the magnetic head main body 62 via the underlayer 24.

[0007] The spiral coil 26 and the magnetoresistive element 23 are electrically connected to a read / write IC for executing recording and reproduction. For this connection, a signal line made of a conductor is used. In the conventional magnetic recording apparatus shown in FIG. 3, a copper wiring (also referred to as a twisted wire for its form) 15 having a thickness of about 30 μm was used. A current corresponding to recording information is supplied to the spiral coil from the read / write IC 14, and a change in voltage or current corresponding to the magnetic information is transmitted to the read / write IC 14 from the magnetoresistive element.

In a conventional magnetic recording apparatus, the frequency at the time of recording and reproduction does not exceed 100 MHz. However, in high-density magnetic recording devices that are currently being developed, attempts have been made to increase the data transfer performance. Specifically, devices having a storage density exceeding 5 GB / in ² have a high-speed recording performance of 150 MH or more. Trying to achieve. In the range where the recording frequency does not exceed 100 MHz,
As shown in FIG. 3, a thin twisted wire is used as the wiring 15 between the read / write IC 14 and the magnetic head 12. However, twisted wires have a large amount of inductive components (inductance components), and thus have a problem in that high-frequency signals associated with high-speed recording are difficult to transmit.

In order to solve this problem, for example, a suspension described in Nikkei Electronics, April 6, 1998, page 168, is about to be used. FIG. 2 is a schematic plan view thereof. Wirings 15 for supplying signals and power are formed directly on the suspension 103. Reference numeral 111 denotes a caulking hole used for attachment to the arm 101. This form is also called a wiring integrated suspension. Since the wiring 15 is formed by a photolithography method, the width of the wiring and the interval between the two lines can be reduced to 30 μm or less. Thereby, the inductance of the wiring can be suppressed to 50 nH or less. From this effect, the apparatus using the wiring-integrated suspension achieves a recording operation of 150 MHz.

[0010]

The performance of a storage device is determined by the speed at the time of input / output operation and the storage capacity. To improve product competitiveness, it is essential to shorten the access time and increase the capacity. To satisfy this requirement, a writing operation using a high-frequency recording magnetic field is required. In order to satisfy this demand, as described above, a wiring-integrated suspension in which wiring is formed directly on the suspension is going to be generally used.

However, according to this technique, a capacitance is generated between the suspension and the line because the suspension is made of metal, and therefore, at a high frequency of about 150 MHz or more, the recording signal waveform is deteriorated, and a desired recording operation is realized. There was a problem that you can not.

A first object of the present invention is to provide a suspension for a magnetic head which can realize a high-frequency recording operation of about 150 MHz or more. A second object of the present invention is to provide a magnetic disk drive capable of realizing a high-frequency recording operation of about 150 MHz or higher.

[0013]

In order to achieve the first object, a suspension according to the present invention supports a magnetic head and at least a pair of wirings for transmitting a recording signal and supplying power to the magnetic head. One is provided thereon, and at least a portion connected to the wiring pair and a portion connected to the arm of the magnetic disk drive are made insulative.

In order to provide insulation, an insulating film may be provided on the surface of the suspension at a portion connected to the wiring pair and the arm, or this portion may be formed of an insulating ceramic such as silicon oxide or aluminum oxide. Is also good.

Further, in order to achieve the second object,
The magnetic disk drive of the present invention includes a magnetic head, a suspension for supporting the magnetic head, and at least one of a pair of wirings provided on the suspension for transmitting recording signals to the magnetic head and supplying power. The suspension is insulated from any of the electric circuits constituting the magnetic disk drive.

[0016]

FIG. 1 is a plan view and a sectional view of a suspension according to a first embodiment of the present invention. FIG. 1 (a)
As shown in FIG. 7, the wiring 112 is formed directly on the suspension 103. Although omitted in the figure, the wiring 11
2 exist in two or more, and two each form one pair. FIG. 1B is a cross-sectional view taken along the line AA. Each wiring 114-1, 114-2, 114-3, 1
14-4 has a width of 10 μm and a thickness of 3 μm. An Au film is plated at 1 μm with Cu as a base. Wiring is 10μm thick
Is formed on the metallic suspension 103 via the polyimide resin 116, and is a so-called strip line. Further, an insulating protective film 117 is provided thereon for the purpose of protecting the line.

Then, in order to keep the suspension 103 electrically insulated, an insulating film 118 is provided on the surface that comes into contact with the arm 101 as shown in FIG. 1C. FIG. 4D shows a state in which the suspension 103 has been removed from the arm. An insulating film 118 is formed on a surface in contact with the arm. This insulating film may not be provided on the entire surface, but it is needless to say that the insulating film is required at least in a portion in contact with the arm. Thus, the suspension made of metal can be electrically insulated from the arm 101 maintained at a predetermined potential.

Conventionally, a suspension having a strip line is mounted on an arm directly connected to a rotary actuator. This arm is electrically maintained at zero potential or a predetermined potential. For this reason, the suspension made of metal is also kept at zero potential or a predetermined potential at the same time. On the other hand, in the present invention, since the suspension 103 is electrically insulated from the arm by adopting the above configuration, the suspension 103 is in a so-called floating state.

The effects of the present invention will be described below. When the suspension 103 is electrically connected to the arm 101,
Since the insulating film is relatively thin, the wiring and the suspension, which is a metal, are close to each other, so that they function as a capacitor. According to calculation and measurement, when a wiring having a length of 3 cm and a width of 20 μm passes through a polyimide resin having a thickness of 3 μm, about 20 PF
Is stored.

It is well known that the higher the frequency of an electric signal, the easier it passes through a capacitor. Therefore, if the suspension is connected to the zero potential or any potential of the signal circuit, high-frequency electric signals leak through the suspension before reaching the magnetic head.

By insulating the suspension from the zero potential or any potential of the signal circuit, the high frequency returning to the read / write IC through the suspension can be reduced, so that the electric signal can be efficiently transmitted to the magnetic head. . From this effect, high-frequency recording of about 150 MHz or more can be realized.

Next, a plan view of a suspension according to a second embodiment of the present invention for electrically insulating the suspension is shown in FIG. In this example, the root portion 120 of the suspension 103 is made of an insulating ceramic containing at least silicon oxide or aluminum oxide. The important thing in this case is to insulate the part that contacts the arm,
Therefore, the base of the suspension is made of an insulating material. It is easily understood by those skilled in the art that this embodiment has the same effect as the above embodiment, and this fact was confirmed by experiments.

By taking measures to insulate the suspension from the electric circuit system, high-frequency signals can be transmitted to the magnetic head with high efficiency and low distortion.
However, in order to transmit a further high frequency signal to the magnetic head, it is preferable to reduce the electric capacity acting between the wirings. That is, even when the suspension is insulated from the electric circuit system, if a potential difference occurs between the wirings, a signal leaks via a capacitor existing under the wirings, so that it is preferable to prevent such leakage.

In the third embodiment of the present invention, a plurality of openings 115 are provided along the longitudinal direction of the suspension 103 as shown in FIG. Thus, the conductive wiring pairs 112-1 and 112-2 for transmitting a recording signal or supplying power to the magnetic head are arranged. As a result, the amount of leakage current flowing between the wirings can be reduced.
, And a recording operation at a frequency of 200 MHz or more was realized.

According to the above embodiment, the loss in the wiring portion can be reduced, and from this effect, high-frequency recording and reproducing operations can be realized. A feature of the present invention that derives this effect is to insulate the suspension provided with the wiring from the electric circuit. As a method of providing the wiring on the suspension, a method by a lithography method, a method of forming a wiring on a polyimide resin and then attaching the wiring to the suspension can be used. It is needless to say that the same effect as in the present embodiment can be obtained by insulating the suspension from the electric circuit in any other method. When there are two pairs of conductive wirings, an opening may be provided between each pair of conductive wirings.

FIG. 5 is a plan view of a suspension according to a fourth embodiment of the present invention. The wiring of the embodiment described so far is
Because it is formed directly on the suspension, for example,
It becomes a parallel line as shown in FIG. In this case, noise may occur in the signal line due to the influence of a disturbance magnetic field acting in the parallel line. In order to prevent this, as shown in FIG. 5, the signal line 113-2 paired with the signal line 113-1 is crossed at a plurality of places. Since the influence of the disturbance magnetic field cancels out in the area adjacent to the intersection, the influence of the disturbance magnetic field can be reduced as compared with the parallel line.

In the crossing wiring pattern, after one wiring is formed, an insulating film is laminated, and then a pair of wirings is formed. In this step, the manufacturing cost is increased because one insulating layer is added, but the effect of reducing noise which has an adverse effect on high-frequency driving cannot be realized with conventional parallel wiring.

If the interval between the portions other than the intersection of the pair of signal lines is wide, an opening may be provided there as in the third embodiment. In this case, good signal transmission with very little noise and little loss between signal lines can be realized.

Next, a magnetic disk drive according to an embodiment of the present invention will be described. Basically, the suspension and wiring of the conventional magnetic disk drive shown in FIG. 3 are changed to the suspension with wiring of the above embodiment. A magnetic head is provided corresponding to each surface of the plurality of recording media, and at least one of a wiring pair for transmitting a recording signal to the magnetic head and supplying power is arranged on a suspension supporting the magnetic head. The suspension is insulated from any of the electric circuits constituting the magnetic disk drive. With this magnetic disk drive, 1
After writing at a high frequency of 50 MHz or higher, a reproducing operation could be realized at the same frequency.

[0030]

As described above, by electrically insulating the wiring suspension, the desired 150M
After writing at about Hz or higher, a reproducing operation could be realized at the same frequency. According to the present invention, a suspension and a magnetic disk drive capable of inexpensive high-frequency recording can be realized by the same technology as the conventional one.

[Brief description of the drawings]

FIG. 1 is a plan view and a sectional view of a suspension according to a first embodiment of the present invention.

FIG. 2 is a plan view of a conventional suspension.

FIG. 3 is a plan view and a cross-sectional view illustrating a basic configuration of a magnetic disk device.

FIG. 4 is a plan view of a suspension according to a third embodiment of the present invention.

FIG. 5 is a plan view of a suspension according to a fourth embodiment of the present invention.

FIG. 6 is a partially cutaway schematic view of a magnetic head element.

FIG. 7 is a plan view of a suspension according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Motor 11-1, 11-2, 11-3, 11-4 ... Recording medium 12 ... Magnetic head 13 ... Rotary actuator 14 ... Read / write IC 15, 112, 112-1, 112-2, 113-1,
113-2, 114, 114-1, 114-2, 114
-3, 114-4: Wiring 21: Writing function unit 22: Reproducing function unit 23: Magnetoresistance effect element 24: Underlayer 25: Magnetic film 26: Spiral coil 27, 28: Magnetic pole 29: Electrode 62: Magnetic head body DESCRIPTION OF SYMBOLS 101 ... Arm 102 ... Case 103 ... Suspension 111 ... Caulking hole 115 ... Opening 116 ... Polyimide resin 117 ... Protective film 118 ... Insulating film 120 ... Root

Claims (10)

[Claims] 1. A suspension for supporting a magnetic head, wherein at least one of a wiring pair for transmitting a recording signal and supplying power to the magnetic head is arranged on the suspension. A suspension characterized in that at least a portion between the wiring pair and a portion connected to an arm of the magnetic disk drive is insulative. 2. The suspension according to claim 1, wherein a portion between the wiring pair and a portion connected to the arm has an insulating film on a surface of the suspension. 3. The suspension according to claim 1, wherein at least a portion connected to the lower portion of the wiring pair and the arm is made of insulating ceramic. 4. The suspension according to claim 1, wherein the suspension has an opening along a longitudinal direction of the suspension, and the wiring pair is positioned so as to sandwich the opening. suspension. 5. The suspension according to claim 1, wherein the wiring pairs cross each other in a plurality of regions. 6. A magnetic head, a suspension for supporting the magnetic head, and at least one of a wiring pair disposed on the suspension for transmitting a recording signal to the magnetic head and supplying power. In the magnetic disk drive, the suspension is insulated from any of the electric circuits constituting the magnetic disk drive. 7. The magnetic disk drive according to claim 6, wherein said suspension has an insulating film at least between said wiring pair and a surface connected to said magnetic disk drive. 8. The magnetic disk drive according to claim 6, wherein at least a portion of the suspension connected to the magnetic disk drive and a lower portion of the wiring pair is made of insulating ceramics. 9. The suspension according to claim 6, wherein the suspension has an opening along a longitudinal direction thereof, and the wiring pair is positioned so as to sandwich the opening. Magnetic disk drive. 10. The magnetic disk drive according to claim 6, wherein the wiring pairs cross each other in a plurality of regions.