JP2001357640A - Thin film piezoelectric actuator for disk device and method of manufacturing the same - Google Patents

Abstract

(57) [Summary] A head can be efficiently displaced according to an applied voltage, and a resonance frequency characteristic required for a suspension can be secured. A head for reproducing at least data from a rotationally driven disk is supported on a substrate supporter. The head is displaced by deforming the support portion 1A of the substrate by the thin film piezoelectric element 4A provided on the support portion 1A. Thin film piezoelectric element 4
A indicates that the first electrode 12 and the second electrode
It has the electrode 14 and the supporting portion 1
A has a terminal hole 17A that reaches the first electrode 12 bonded to the first electrode 12 with the adhesive 10, and inside the terminal hole 17A,
A lead wire 18A connected to the first electrode 12 is provided,
It is drawn to the second electrode 14 side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head support mechanism used for recording and reproducing information on and from a disk of a disk device in a storage device of a computer, and more particularly, to recording of information on a disk provided in the disk device. The present invention relates to a thin-film piezoelectric actuator used as an optimum head support mechanism for increasing the density of a piezoelectric element.

[0002]

2. Description of the Related Art Data recording density on a disk provided in a disk drive tends to be increased.
The recording density of data on a magnetic disk provided in a magnetic disk device is increasing with each passing day. A magnetic head used for recording and reproducing data on and from a magnetic disk is usually mounted on a slider, and the slider on which the magnetic head is mounted is supported by a head support mechanism provided in the magnetic disk device. .
The head support mechanism has a head actuator arm on which a slider is mounted, and this head actuator arm is connected to a voice coil motor (VCM).
To be rotated. And VCM
, The magnetic head mounted on the slider is positioned facing an arbitrary position on the magnetic disk.

In order to record data on a magnetic disk at a higher density, it is necessary to position the magnetic head with respect to the magnetic disk with higher precision. However, the configuration in which the magnetic head is positioned by rotating the head actuator arm in the VCM has a problem that the magnetic head cannot be positioned with higher accuracy. Various proposals have been made to solve this problem. In particular, in recent years, a thin film piezoelectric actuator that displaces a magnetic head in a minute range by using a piezoelectric material having a property of expanding and contracting by applying a voltage has been proposed. Hereinafter, an example of a suspension equipped with such a thin film piezoelectric actuator will be described.

FIG. 3 is a perspective view showing the overall structure of an example of a suspension on which a thin film piezoelectric actuator is mounted.
FIG. 4 is an exploded perspective view showing the suspension 26 of FIG.

A suspension 26 on which the thin film piezoelectric actuators 5A and 5B are mounted has a slider holding plate 2 for holding a slider (not shown) on which a magnetic head is mounted, and the slider and the slider holding plate 2 are mounted on the tip. A load beam 6 rotatably supported, a thin-film piezoelectric substrate 1 as an operation substrate for supporting a slider on the distal end on the load beam 6 and rotating the slider, and a thin-film piezoelectric substrate 1 , A first wiring pattern 20 provided from the front end to the base end of the thin film piezoelectric substrate 1, and a second wiring provided along the first wiring pattern 20. And a pattern 21.

The load beam 6 has a square base portion 6A, a neck portion 6C extending from the base portion 6A toward the distal end, and a taper shape further extending from the neck portion 6C toward the distal end. The slider holding plate 2 is mounted on a mounting portion 6G provided at the tip of the beam portion 6E.

[0007] A square base plate 7 corresponding to the base end 6A is attached to the lower surface of the base end 6A of the load beam 6 by beam welding or the like. The base plate 7 is pivotally attached to a head actuator (not shown), and a load beam 6 is provided.
Is driven to rotate around the base end 6A by a head actuator such that the front end of the beam portion 6E moves in a substantially radial direction of a magnetic disk (not shown). Therefore, the slider is moved along a substantially radial direction of the magnetic disk by the turning drive of the load beam 6 in this manner.

A circular opening 6B is provided at the center of the base end 6A of the load beam 6, and a triangular opening 6D is provided at the center of the neck 6C. Both sides of the triangular opening 6D in the neck 6C are leaf springs 6I and 6J, respectively. The mounting portion 6G is elastically displaced in a direction perpendicular to the surface of the magnetic disk by the leaf spring portions 6I and 6J, and the mounting portion 6G is elastically displaced by the mounting portion 6G. Slider (not shown) provided on
, A load is applied.

The mounting portion 6G is integrally formed with dimples 6H projecting hemispherically toward the upper surface. The mounting portion 6G is further provided with a pair of regulating portions 6F, 6F extending linearly from the distal end of the mounting portion 6G toward the base end side. Each restricting portion 6F extends toward the base end with an appropriate gap above the upper surface of the mounting portion 6G.

A slider is held on the slider holding plate 2 mounted on the mounting portion 6G via the tip of the thin film piezoelectric substrate 1. In the center of the slider holding plate 2 at the base end side, a protrusion 2A protruding in a semicircular shape toward the base end side.
Is provided.

The protrusion 2A of the slider holding plate 2 is attached to a dimple 6H provided on the mounting portion 6G of the load beam 6.
The slider holding plate 2 is supported by point contact from below, and both ends of the slider holding plate 2 are regulated with a suitable minute interval from each regulating portion 6F provided on the mounting portion 6G. Thus, the slider holding plate 2 is supported so as to be able to rotate in all directions at a small displacement angle together with the slider provided thereon.

The thin-film piezoelectric substrate 1 has a long plate shape extending from the distal end to the proximal end of the load beam 6.
It is arranged along the surface of the magnetic disk. A slider attaching portion 1C disposed on the slider holding plate 2 is provided at the tip of the thin film piezoelectric substrate 1, and a slider is attached on the slider attaching portion 1C. The side edge on the base end side of the slider holding plate 2 is substantially aligned with the side edge on the base end side of the slider attachment portion 1C.

The substrate holding portion 1D of the thin film piezoelectric substrate 1 has a leaf spring portion 6I of the load beam 6 and a base end portion 6A.
The wiring portion 1G disposed on one side of the wiring portion 1G is provided continuously, and the terminal holding portion 1H is provided at the base end of the wiring portion 1G.

FIG. 5 is a plan view of the tip of the thin-film piezoelectric substrate 1 arranged on the load beam 6, and FIG.
FIG. 4 is a schematic cross-sectional view taken along line -A ′.

On the base end side of the slider attaching portion 1C,
A pair of support portions 1A and 1B respectively forming a pair of thin film piezoelectric actuators 5A and 5B that expand and contract in different phases in the horizontal direction with respect to the surface of the magnetic disk.
Respectively, via the elastic hinge portions 1E and 1F,
It is provided integrally. The base ends of the support portions 1A and 1B are respectively continuous with the rectangular substrate holding portion 1D. The substrate holding section 1D is fixed to the upper surface of the beam section 6E of the load beam 6 via the stainless steel plate 3.

The pair of supports 1A and 1B are parallel at a predetermined interval. A pair of elastic hinges 1E
And 1F are formed by reducing the width dimensions of the tip portions of the support portions 1A and 1B, respectively.
The slider attaching portion 1C can be rotated in all directions at a small displacement angle by the elastic hinge portions 1E and 1F. Therefore, the slider and the slider attaching portion disposed on the slider attaching portion 1C are provided. The slider holding plate 2 disposed below the attachment portion 1C can rotate in all directions at a small displacement angle.

Each of the supporting portions 1A and 1B is formed by covering a 3 μm thick copper plate 8 with a polyimide resin 9 as an insulator, and the thin film piezoelectric elements 4A and 4A are provided on the upper surfaces of the supporting portions 1A and 1B. 4B is adhesive 1
0 is attached in a laminated state, and is integrated with each of the support portions 1A and 1B. The supporting portions 1A and 1B of the thin-film piezoelectric substrate 1 are thin-film piezoelectric elements 4A and 4B
Together, they constitute the thin film piezoelectric actuators 5A and 5B, respectively. Note that, instead of the copper plate 8, a metal plate such as stainless steel may be used.

The thin-film piezoelectric substrate 1 is provided with a first wiring pattern 20 for transferring a recording / reproducing signal to a magnetic head (not shown). The first wiring pattern 20 has four wiring lines 20A to 20D. One end of each of the wiring lines 20A to 20D is
Four slider connection terminals 22A, 22B, 22 provided on slider attachment portion 1C of thin film piezoelectric substrate 1
C and 22D. Then, the four slider connection terminals 22A, 22B, 22C, 22D
Is a slider attaching portion 1 on the thin film piezoelectric substrate 1.
Each terminal is connected to each terminal (not shown) provided on the slider on the upper surface of C.

A pair of wiring lines 20A and 20B of the first wiring pattern 20 connected to the slider connection terminals 22A and 22B are formed on the thin film piezoelectric member 1 provided on one support portion 1A of the thin film piezoelectric substrate 1. The body element 4A is drawn to the base end side through the side portion and the substrate holding portion 1D. Slider connection terminals 22C and 2
Another pair of wiring lines 20C respectively connected to 2D
And 20D are the other support portions 1 of the thin film piezoelectric substrate 1.
It passes through the thin film piezoelectric element 4B provided on B and the substrate holding portion 1D, and is drawn out to the base end side.

The four wiring lines 20A to 20D drawn to the base end side of the thin film piezoelectric substrate 1 pass through the wiring portion 1G, and the external connection terminals 24C to 24C provided on the terminal holding portion 1H. 24F, respectively.

The four wiring lines 20A to 20D
Is a polyimide resin 9 for the thin film piezoelectric substrate 1.
Has been fixed by.

The second wiring pattern 21 is used for driving two thin film piezoelectric elements 4A and 4B arranged on the upper surface of the thin film piezoelectric substrate 1. Second wiring pattern 21
Is composed of four wiring lines 21A to 21D. A pair of thin film piezoelectric element connection terminals 23A, 23B, 23C, and 23D are exposed from the polyimide resin 9 on the base end side of the support portions 1A and 1B in the thin film piezoelectric substrate 1, respectively. Is provided. One end of each of the wiring lines 21A to 21D is connected to four thin film piezoelectric element connecting terminals 23A, 23B, 23C, 23D on the base end sides of the pair of support plates 1A and 1B, respectively. .

Wiring line 21 of second wiring pattern 21
A to 21D pass through the substrate holding portion 1D of the thin film piezoelectric substrate 1 and are respectively drawn to the base end side.

The four wiring lines 21A to 21D drawn to the base end side of the thin film piezoelectric substrate 1 pass through the wiring portion 1G and are connected to the external connection terminals 24A to 24A on the terminal holding portion 1H.
24B, 24G to 24H, respectively.

These four wiring lines 20A to 20D
Also, for the thin film piezoelectric substrate 1, a polyimide resin 9
Has been fixed by.

FIG. 7 is a cross-sectional view taken along the line AA 'of FIG. 5, and shows one thin film piezoelectric actuator 5A in detail.

The thin-film piezoelectric element 4A has a lead zirconate titanate (PZT) thin film 13, which is a piezoelectric material, and a voltage is applied between its upper and lower surfaces to correspond to the voltage. The elastic deformation occurs in the longitudinal direction, and the elastic deformation generated in the thin film piezoelectric element 4A causes the thin film piezoelectric actuator 5A to expand and contract in the longitudinal direction. Thereby, the slider attaching portion 1C
Is rotated in all directions at a small displacement angle.

A first electrode 12 and a second electrode 14 made of platinum are provided on the upper and lower surfaces of the lead zirconate titanate (PZT) thin film 13 of the thin film piezoelectric element 4A, respectively. 14, the second electrode 1
A lead wire 18 electrically connected to 4 is drawn out to the side of the thin film piezoelectric element 4A. The other thin film piezoelectric actuator 5B has a similar structure.

The pair of thin film piezoelectric element connecting terminals 23A and 23B are attached to the first electrode 12 and the lead 18 of the thin film piezoelectric element 4A in a conductive state, respectively. Similarly, a pair of thin film piezoelectric element connection terminals 23C
And 23D are attached to the first electrode 12 and the lead wire 18 of the thin film piezoelectric element 4B in a state of being in electrical contact with each other.

The thin film piezoelectric actuators 5A and 5
The operation of B will be described with reference to FIGS.

The thin film piezoelectric elements 4A and 4B correspond to the voltages applied to the first electrodes 12 and the lead wires 18 of the thin film piezoelectric elements 4A and 4B, respectively, in the longitudinal direction of the thin film piezoelectric elements 4A and 4B. It is designed to expand and contract equally. Accordingly, by applying mutually opposite voltages to the thin film piezoelectric elements 4A and 4B attached to the upper surfaces of the support portions 1A and 1B of the thin film piezoelectric substrate 1, the thin film piezoelectric actuators 5A and 5B are applied.
Expands and contracts in directions opposite to each other in the longitudinal directions La and Lb, corresponding to the voltages applied to the thin film piezoelectric elements 4A and 4B.

The thin film piezoelectric actuators 5A and 5A are provided on the slider attaching portion 1C and the slider holding plate 2.
When B expands and contracts in opposite directions to each other, the point of contact between the dimple 6H provided on the load beam 6 and the protrusion 2A protruding from the slider holding plate is set as a rotation center.
A small angular displacement in the R direction is given. The minute angular displacement in the R direction given to the slider attaching portion 1C and the slider holding plate 2 imparts a small angular displacement in the R direction to the slider attached to the upper surface of the slider attaching portion 1C. The magnetic head mounted on the slider is displaced along the surface of the magnetic disk in a minute range in the width direction of each track provided concentrically on the magnetic disk, and moves with high precision. Thus, it is possible to perform the on-track operation for following the track of the magnetic head with high accuracy.

A method of manufacturing a conventional thin film piezoelectric actuator having such a configuration will be described with reference to FIGS. The description will be made only for the thin film piezoelectric actuator 5A.

First, an outline of a conventional method for manufacturing a thin film piezoelectric actuator will be described with reference to FIG.

FIGS. 8A to 8F are schematic sectional views showing respective steps of a conventional method of manufacturing a thin film piezoelectric actuator. First, as shown in FIG. 8A, a thin-film piezoelectric element 4A is formed on a magnesium oxide substrate 11. On the other hand, a thin film piezoelectric substrate 1 is prepared. FIG.
FIG. 2B is a cross-sectional view of one support 1A provided on the thin film piezoelectric substrate 1, and an adhesive 10 is applied on the support 1A of the prepared thin film piezoelectric substrate 1. FIG. Next, as shown in FIG. 8C, the thin-film piezoelectric element 4A supported by the magnesium oxide base 11 is placed on the support 1A.
Adhesion is performed using an adhesive 10. After the adhesive 10 is cured and the thin-film piezoelectric element 4A is fixed on the magnesium oxide substrate 11, as shown in FIG.
Is removed.
Thereafter, as shown in FIG. 8E, the thin film piezoelectric element 4A
Connection terminal (not shown) provided on the support portion 1A
The thin-film piezoelectric element connection terminals (not shown) provided above are connected in a conductive state using the leads 19, respectively. Finally, as shown in FIG. 8F, the two leads 19, the thin film piezoelectric element 4A, and the adhesive 10 are covered with the polyimide resin 9. Thereby, the thin film piezoelectric actuator 5A is obtained.

Next, a method for manufacturing a conventional thin film piezoelectric actuator will be described in more detail with reference to FIG.

FIGS. 9A to 9G are cross-sectional views of respective steps for explaining the method of manufacturing the thin film piezoelectric actuator in further detail.

First, as shown in FIG. 9A, an electrode for supplying power to the thin film piezoelectric element 4A is formed on a magnesium oxide substrate 11 used as a sputtering base for forming the thin film piezoelectric element 4A. First electrode 12,
A thin film piezoelectric member 15 is formed by sequentially forming and stacking a thin film 13 of lead zirconate titanate (PZT), which is a piezoelectric material, and a second electrode 14 as a power supply electrode by sputtering. In this step, the film formation temperature of each thin film is set at 600 ° C.
2 is 200 nm, the PZT thin film 13 is 3 μm, the second electrode 1
4 is set to 200 nm.

Next, as shown in FIG. 9B, a necessary portion of the thin film piezoelectric material 15 is protected by a photoresist or the like by a photolithographic process and a developing process, and thereafter, a chemical etching process of etching an unnecessary portion with a chemical solution. Or, by a reactive ion etching process or the like that etches unnecessary parts with a reactive gas,
Thin film piezoelectric member 15 formed on magnesium oxide substrate 11
Is molded into a predetermined shape.

In such a state, as shown in FIG. 9C, a photosensitive polyimide 16 is applied to the surfaces of the magnesium oxide substrate 11 and the thin film piezoelectric member 15 formed into a predetermined shape, and a photolithographic process and The photosensitive polyimide 16 is thermally cured after the photosensitive polyimide is formed into a predetermined shape by a developing process and an opening 17B for taking out the lead wire 18 is formed.

Thereafter, Ta / Au is sputtered on the surfaces of the magnesium oxide substrate 11, the thermally cured photosensitive polyimide 16 and the second electrode 14 exposed from the opening 17B for taking out the lead wire 18, thereby forming Ta. /
An Au thin film is formed. Then, from this Ta / Au thin film, as shown in FIG. 9D, a lead wire 18 electrically connected to the second electrode 14 is formed by a patterning process,
The thin film piezoelectric element 4A is manufactured.

Next, as shown in FIG. 9E, an adhesive 10 is applied to the upper surface of the support plate 1A provided on the thin film piezoelectric substrate 1, and is then supported by the magnesium oxide substrate 11. The thin film piezoelectric element 4A is attached to the upper surface of the support plate 1A with the second electrode 14 facing downward, and then the adhesive is cured.

When the adhesive is cured, as shown in FIG. 9 (f), the thin film piezoelectric substrate 1 on which the thin film piezoelectric element 4A supported by the magnesium oxide substrate 11 is attached is put into a phosphoric acid solution at 60 ° C. Dipped, magnesium oxide substrate 11
Is removed by chemical etching. After that, the thin-film piezoelectric substrate 1 from which the magnesium oxide substrate 11 has been removed is sufficiently washed with warm water, and then sufficiently dried in a vacuum dryer.

Finally, as shown in FIG. 9 (g), the lead wire 18 pulled out from the thin film piezoelectric element 4A is connected to the thin film provided on the base end side of the supporting portion 1A of the thin film piezoelectric substrate 1. The first electrode 12 is electrically connected to the piezoelectric element connection terminal 23A and the thin film piezoelectric element connection terminal 23B using the lead 19, respectively. And the thin film piezoelectric element 4
A, adhesive 10 and leads 19 are entirely covered with polyimide resin 9. Thereby, the thin film piezoelectric actuator 5A shown in FIG. 7 is obtained.

When manufacturing the thin film piezoelectric actuator 5A, a plurality of thin film piezoelectric substrates 1 are prepared.
Each of the thin film piezoelectric elements 4A and 4B is placed on a single magnesium oxide substrate 11 so that the thin film piezoelectric elements 4A and 4B are attached to the support portions 1A and 1B of the thin film piezoelectric substrate 1, respectively. It is arranged corresponding to the arrangement of the support portions 1A and 1B of the thin film piezoelectric substrate 1. Then, in a state where the thin film piezoelectric elements 4A and 4B are provided on the magnesium oxide substrate 11, the thin film piezoelectric elements 4A and 4B and the corresponding support portions 1A and 1B of the corresponding thin film piezoelectric substrate 1 are formed. Are aligned, and attached on each of the support portions 1A and 1B of the thin film piezoelectric substrate 1 with an adhesive.

The surface of the thin film piezoelectric element 4A to be attached to the support portion 1A is provided with the lead wires 18 and the photosensitive polyimide 16, and has an uneven shape. The attachment surface having such an uneven shape is abutted on each of the support portions 1A and 1B of the thin film piezoelectric substrate 1, and the thin film piezoelectric elements 4A and 4B are set in a predetermined posture with respect to the support portions 1A and 1B. In order to adhere with the adhesive 10, the thin film piezoelectric elements 4A and 4B need to be held in a predetermined posture with respect to the supports 1A and 1B until the adhesive 10 is cured.

Thus, the magnesium oxide substrate 11
Is used as a sputtering base for forming the thin film piezoelectric elements 4A and 4B, and as a jig for holding the thin film piezoelectric elements 4A and 4B on the supporting portions 1A and 1B in a predetermined posture. Is also used. Then, when the adhesive 10 is cured, the magnesium oxide substrate 11 is removed from the thin film piezoelectric elements 4A and 4B adhered to the supports 1A and 1B.

[0048]

However, when the thin film piezoelectric elements 4A and 4B are attached on the supporting portions 1A and 1B, the magnesium oxide substrate 11
As a result, the thin film piezoelectric elements 4A and 4B
Until 0 cures, for each support 1A and 1B,
In order to be held in a predetermined posture, each of the support portions 1A and 1A
In the thin film piezoelectric elements 4A and 4B pasted on B, a compressive stress due to a difference in thermal expansion coefficient between the magnesium oxide substrate 11 and the thin film piezoelectric body 15 generated when the thin film piezoelectric body 15 is formed is applied. There is a problem that it remains as internal stress. When the internal stress remains in the thin film piezoelectric elements 4A and 4B, the thin film piezoelectric elements 4A and 4B
May decrease the effective piezoelectric constant d31.

Further, since the internal stress remains in the thin film piezoelectric elements 4A and 4B, the thin film piezoelectric actuators 5A and 5B may be warped.

In order to perform on-track scanning with high accuracy by using the suspension 26 to cause the magnetic head mounted on the slider to follow a track provided concentrically on the magnetic disk, the slider must have a radius equal to the radius of the magnetic disk. It is necessary to slightly displace in the direction. For this purpose, it is necessary to expand and contract the thin film piezoelectric elements 4A and 4B. Specifically, the thin film piezoelectric elements 4A and 4B
It is necessary to apply a voltage of V and 6V alternately to displace the slider holding plate 2 in the radial direction of the magnetic disk by the thin film piezoelectric elements 4A and 4B, so that the displacement of the slider is about 1 μm.

As shown in FIG. 10, the base end of the thin-film piezoelectric substrate 1 on which the thin-film piezoelectric elements 4A and 4B are provided is placed on a support 27 via a stainless steel plate 3 to form a thin-film piezoelectric element. When the piezoelectric elements 4A and 4B are supported in a cantilever manner from the support 27, the amount of warpage of each of the thin-film piezoelectric actuators 5A and 5B when no voltage is applied needs to be 400 μm or less. .

However, if the effective piezoelectric constant d31 of the thin film piezoelectric elements 4A and 4B is reduced due to the residual internal stress in the thin film piezoelectric elements 4A and 4B, the expansion and contraction performance of the thin film piezoelectric elements 4A and 4B is reduced. And the displacement of the slider holding plate 2 by the thin film piezoelectric actuators 5A and 5B may not be able to be reduced to about 1 μm. The same problem occurs when the internal stress remains in the thin-film piezoelectric elements 4A and 4B, causing a warp larger than 400 μm in the thin-film piezoelectric actuators 5A and 5B. As a result, on-track scanning for causing the magnetic head to follow the track cannot be performed with high accuracy.

Further, it is possible to prevent the slider from colliding with the surface of the magnetically driven magnetic disk, to output information from the magnetic head when reproducing information recorded on the magnetic disk, and to store information on the magnetic disk. In order to control the magnetic intensity at the time of recording within a predetermined range, it is necessary to keep the distance between the magnetic head and the rotationally driven magnetic disk constant. For this purpose, the resonance frequency of the suspension 26 needs to be set to 10 kHz.
The thickness of the copper plate 8 provided on the support portions 1A and 1B is 5 μm.
In the case of m, the length of the thin film piezoelectric elements 4A and 4B provided on the supporting portions 1A and 1B in the expansion and contraction direction must be 5 mm or less.

However, when the length of the thin-film piezoelectric elements 4A and 4B in the direction of expansion and contraction is set to 5 mm or less, it is effective for suppressing the warpage of the thin-film piezoelectric actuators 5A and 5B. There is a possibility that the absolute amount of the expansion and contraction deformation of 5A and 5B may be insufficient, and also in this case, on-track scanning of the magnetic head may not be performed with high accuracy.

An object of the present invention is to solve such a problem, and an object of the present invention is to efficiently displace a slider with respect to an applied voltage and to secure resonance frequency characteristics required for a suspension. An object of the present invention is to provide a thin film piezoelectric actuator and a method of manufacturing the same.

[0056]

According to the present invention, there is provided a thin-film piezoelectric actuator comprising a head supporting mechanism in which at least a head for reproducing data from a rotationally driven disk is supported on a supporting portion of a substrate. A thin film piezoelectric element for a disk drive for displacing the head by deforming a supporting portion of the substrate by using a thin film piezoelectric element provided on the portion, wherein the thin film piezoelectric element has electrodes on both surfaces of the thin film piezoelectric material. And a terminal hole extending from one electrode to the other electrode, and a lead wire connected to the other electrode is provided inside the terminal hole, and is drawn out to the one electrode side. A thin film piezoelectric actuator.

The head is disposed between the tips of supporting portions of the substrate which are disposed in parallel with each other;
A thin-film piezoelectric element is provided on each support.

The thin-film piezoelectric element has a warpage of 400 μm or less when no head is mounted between the support portions of the substrate and no voltage is applied.

Each supporting portion of the substrate is provided with a 5 μm metal plate, and the length of each of the thin film piezoelectric elements provided on each supporting portion is 5 mm or less in the direction of expansion and contraction.

According to the method of manufacturing a thin film piezoelectric actuator of the present invention, in a head support mechanism in which at least a head for reproducing data from a disk driven to rotate is supported on a support portion of a substrate, A method of manufacturing a thin-film piezoelectric actuator for a disk drive, in which a head is displaced by deforming a supporting portion of the substrate by using a provided thin-film piezoelectric element, wherein a thin-film piezoelectric body is formed on a substrate by a sputtering process. Forming a thin film piezoelectric element by forming a lead wire on the formed thin film piezoelectric material by a photolithographic process and an etching process; and removing the formed thin film piezoelectric element from a substrate on a substrate. And adhering to the substrate.

[0061]

Embodiments of the present invention will be described below with reference to the drawings.

The present invention is applied to a pair of thin film piezoelectric actuators 5A and 5B in the head support mechanism shown in FIGS. FIG. 1 is a sectional view of a thin film piezoelectric actuator 5A of the present invention. The other thin film piezoelectric actuator 5B has the same configuration as the thin film piezoelectric actuator 5A.

The thin film piezoelectric actuator 5 shown in FIG.
A has a thin film piezoelectric element 4A bonded to one support portion 1A of the thin film piezoelectric substrate 1 with an adhesive 10.

In the thin film piezoelectric element 4A, a second electrode 14 and a first electrode 12 made of platinum are provided on the upper and lower surfaces of a lead zirconate titanate (PZT) thin film 13, which is a piezoelectric material, respectively. The thin film piezoelectric member 15 is provided. The first electrode 12 of the thin film piezoelectric body 15 is
0 is attached to the support 1A.

When a voltage is applied between the first electrode 12 and the second electrode 14, the thin film piezoelectric element 4A undergoes expansion and contraction in the longitudinal direction of the thin film piezoelectric element 4A in accordance with the voltage. Similarly, the thin-film piezoelectric element 4B of the other thin-film piezoelectric actuator 5B is also configured to be expanded and contracted in the longitudinal direction of the thin-film piezoelectric element 4B in response to the voltage. And 4B expand and contract, the slider attaching portion 1C (see FIG. 4) is rotated in all directions at a small displacement angle.

The thin film piezoelectric element 4A has a terminal hole 17A extending from the second electrode 14 to the first electrode 12. The thin film piezoelectric element 4A is covered with the photosensitive polyimide 16 except for a part of the second electrode 14, and the inner surface of the terminal hole 17A is also covered with the photosensitive polyimide 16. The first electrode 1 is provided in the terminal hole 17A.
A lead wire 18A electrically connected to the second electrode 14 is provided, and the lead wire 18A is drawn out to the second electrode 14 side.

The second electrode located on the upper surface of the thin film piezoelectric element 4A
A part of the electrode 14 is exposed from the opening 17B of the photosensitive polyimide 16, and the second region is formed in the opening 17B.
A lead wire 18B connected to the electrode 14 is provided. The lead wire 18B is drawn out onto the photosensitive polyimide 16 through the opening 17B. Lead wire 18A and lead wire 1 drawn out on thin film piezoelectric element 4A
8B are insulated from each other by a photosensitive polyimide 16, and a pair of thin film piezoelectric elements provided on the support 1A by leads 19 provided to cover each side of the thin film piezoelectric element 4A. The terminals are electrically connected to the connection terminals 23A and 23B, respectively. The other thin film piezoelectric actuator 5B has the same configuration.

FIGS. 2A to 2G are cross-sectional views showing steps of a method of manufacturing a thin film piezoelectric actuator according to the present invention.

First, as shown in FIG. 2A, an electrode for supplying power to the thin film piezoelectric element 4A is formed on a magnesium oxide substrate 11 used as a sputtering base for forming the thin film piezoelectric element 4A. First electrode 12,
A thin film piezoelectric body 15 is formed by laminating a lead zirconate titanate (PZT) thin film 13 as a piezoelectric material and a second electrode 14 as a power supply electrode by sputtering.
In this step, the film forming temperature condition of each thin film is 600 ° C., and the film thickness of each thin film is
0 nm, the PZT thin film 13 is 3 μm, and the second electrode 14 is 20 μm.
It is set to 0 nm.

Next, after a necessary portion of the thin film piezoelectric material 15 is protected by a photoresist or the like by a photolithographic process and a developing process, the unnecessary portion is etched by a chemical solution, or the unnecessary portion is etched by a reactive gas. As shown in FIG. 2B, the thin film piezoelectric body 15 formed on the magnesium oxide substrate 11 is formed into a predetermined shape by a reactive ion etching process or the like. In such a state, the second electrode 14 and the lead zirconate titanate (PZT) thin film 13
Then, a terminal hole 17A reaching the first electrode 12 is formed.

Next, as shown in FIG. 2C, a photosensitive polyimide 16 is applied to the surfaces of the magnesium oxide substrate 11 and the thin film piezoelectric body 15 formed into a predetermined shape, and the photosensitive polyimide 16 is subjected to a photosensitive lithography process and a developing process. A polyimide is formed into a predetermined shape. Thereby, the photosensitive polyimide 16 has an opening 1 where the second electrode 14 is exposed.
7B are formed, and the inner surface of the terminal hole 17A is covered with the photosensitive polyimide 16. Thereafter, the photosensitive polyimide 16 is thermally cured.

In such a state, as shown in FIG. 2D, the magnesium oxide base 11 and the terminal holes 17A are formed.
And Ta that contacts the first electrode 12 and the second electrode 14 by sputtering Ta / Au in the opening 17B provided in the photosensitive polyimide 16 that has been thermally cured.
After forming the / Au thin film, the Ta / Au thin film is patterned into a predetermined shape by a patterning process. As a result, lead wires 18A and 18B that are electrically connected to the first electrode 12 and the second electrode 14 are formed, and the thin film piezoelectric element 4A is manufactured.

Next, as shown in FIG. 2E, the magnesium oxide substrate 11 supporting the thin film piezoelectric element 4A is immersed in a phosphoric acid solution at 60 ° C.
Is removed by chemical etching. After that, the thin film piezoelectric element 4 removed from the magnesium oxide base 11
After thoroughly washing A with warm water, it is sufficiently dried in a vacuum dryer.

Next, as shown in FIG. 2F, after the adhesive 10 is applied to the upper surface of the support plate 1A provided on the thin film piezoelectric substrate 1, the thin film removed from the magnesium oxide base 11 is removed. The piezoelectric element 4A is attached to the upper surface of the support plate 1A with the second electrode 14 facing upward, and the adhesive is cured.

Finally, as shown in FIG. 2 (g), the lead wire 18A pulled out from the first electrode 12 of the thin film piezoelectric element 4A is placed on the base end side of the supporting portion 1A of the thin film piezoelectric substrate 1. The lead 18B drawn out from the second electrode 14 of the thin film piezoelectric element 4A is electrically connected to the thin film piezoelectric element connection terminal 23A by using the lead 19 to the provided thin film piezoelectric element connection terminal 23A. Connect to Then, the entire thin film piezoelectric element 4A including the leads 19 is covered with the epoxy resin 25, and further, the entire thin film piezoelectric element 4A, the adhesive 10 and the epoxy resin 25 are covered with the polyimide resin 9. Thus, the thin film piezoelectric actuator 5A shown in FIG. 1 is obtained.

The thin film piezoelectric actuator 5A manufactured as described above operates according to the same operating principle as the thin film piezoelectric actuator shown in FIG. 7 by applying a voltage to each terminal provided on the terminal holding portion 1H. Works similarly.

The thin film piezoelectric actuator 5A of the present invention
According to the manufacturing method, the thin film piezoelectric element 4A is adhered onto the support portion 1A with the magnesium oxide substrate 11 removed and the thin film piezoelectric element 4A removed from the magnesium oxide substrate 11. Thereby, the thin film piezoelectric element 4A
The internal stress remaining in the thin film piezoelectric element 4A is prevented from lowering, and the thin film piezoelectric actuator 5A is prevented from warping.

Further, the thin film piezoelectric elements 4A and 4B
Is adhered to the supporting portions 1A and 1B while the thin film piezoelectric elements 4A and 4B are detached from the magnesium oxide substrate 11, so that the thin film piezoelectric elements 4A and 4B are formed on the magnesium oxide substrate 11. In this case, it is not necessary to make the absolute positions of the thin film piezoelectric elements 4A and 4B on the magnesium oxide substrate 11 correspond to the shape and arrangement of the thin film piezoelectric substrate 1. Accordingly, a large number of thin film piezoelectric elements 4A and 4B are formed on one magnesium oxide substrate 11.
Can be arranged close to each other, and the thin film piezoelectric elements 4A and 4B can be efficiently manufactured in a small space. As a result, the thin film piezoelectric elements 4A and 4B can be manufactured at low cost.

The thin film piezoelectric actuator 5A of the present invention
The thin-film piezoelectric element 4A of FIG. 1 has a terminal hole 17A extending from the second electrode 14 to the first electrode 12 in the thin-film piezoelectric element 4A.
Is provided, and the lead wire 18A connected to the first electrode 12 is drawn out toward the second electrode 14 inside the terminal hole 17A, so that the bonding surface to the support portion 1A becomes flat. Thus, the thin-film piezoelectric element 4A can be bonded to the support 1A in a predetermined posture without being supported by the magnesium oxide substrate 11.

In the thin film piezoelectric elements 4A and 4B of the present invention, voltages of 0 V and 6 V are alternately applied to displace the slider holding plate 2 in the radial direction of the magnetic disk by the thin film piezoelectric elements 4A and 4B. Thereby, the amount of displacement of the slider can be reduced to about 1 μm.

As shown in FIG. 10, the base end of the thin film piezoelectric substrate 1 provided with the thin film piezoelectric elements 4A and 4B is placed on a support 27 via a stainless steel plate 3, and When the piezoelectric elements 4A and 4B are supported in a cantilevered state from the support 27, the amount of warpage of each of the thin film piezoelectric actuators 5A and 5B when no voltage is applied is 400 μm or less.

Thus, in the thin-film piezoelectric actuator of the present invention, the effective piezoelectric constant d31 of the thin-film piezoelectric elements 4A and 4B hardly decreases, and on-track scanning for causing the magnetic head to follow the track can be performed with high accuracy. Can be implemented.

When the thickness of the copper plate 8 provided on the support portions 1A and 1B is 5 μm, the support portions 1A and 1B
The length of the thin film piezoelectric elements 4A and 4B provided on the upper and lower sides in the expansion and contraction direction can be set to 5 mm or less.
The resonance frequency of the suspension 26 can be set to 10 kHz.

[0084]

As described above, according to the thin film piezoelectric actuator and the method of manufacturing the same of the present invention, the thin film piezoelectric element
After the internal stress is released, the thin film piezoelectric actuator can be effectively stuck on the supporting portion after the internal stress is released. Therefore, the effective piezoelectric constant d31 of the thin-film piezoelectric element does not decrease, and the expansion and contraction of the thin-film piezoelectric actuator is efficiently converted into the rotational displacement of the slider holding plate, so that the magnetic head follows the track. On-track scanning can be performed with high accuracy.

Further, since the thin-film piezoelectric element is adhered to the supporting portion in a state where it is detached from the base, the thin-film piezoelectric element can be freely arranged when the thin-film piezoelectric element is formed on the base. Thus, a large number of thin film piezoelectric elements can be formed close to each other on the substrate. Therefore, the thin-film piezoelectric element can be manufactured efficiently at low cost, and the thin-film piezoelectric actuator can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a thin film piezoelectric actuator according to an embodiment of the present invention.

FIGS. 2A to 2G are cross-sectional views illustrating respective steps of a method for manufacturing the thin-film piezoelectric actuator.

FIG. 3 is a perspective view of an example of a suspension on which a conventional thin film piezoelectric actuator is mounted.

FIG. 4 is an exploded perspective view of an example of a suspension equipped with a conventional thin film piezoelectric actuator.

FIG. 5 is a plan view for explaining the operation of the thin film piezoelectric actuator.

FIG. 6 shows a conventional thin film piezoelectric actuator AA ′.
It is a cross section schematic diagram in a line.

FIG. 7 is a sectional view of a conventional thin film piezoelectric actuator.

FIGS. 8A to 8F are cross-sectional views showing respective steps of a conventional method for manufacturing a thin-film piezoelectric actuator.

FIGS. 9A to 9G are cross-sectional views of respective steps for describing in further detail a conventional method of manufacturing a thin film piezoelectric actuator.

FIG. 10 is a schematic diagram for explaining a warp amount x of the thin film piezoelectric actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thin film piezoelectric substrate 1A, 1B Support part 1C Slider attaching part 1D Substrate holding part 1E, 1F Elastic hinge part 1G Wiring part 1H Terminal holding part 2 Slider holding plate 2A Projection part 3 Stainless steel plate 4A, 4B Thin film piezoelectric element 5A, 5B Thin-film piezoelectric actuator 6 Load beam 6A Base end 6B Circular opening 6C Neck 6D Triangular opening 6E Beam 6F Regulator 6G Mounting 6H Dimple 6I, 6J Plate spring 7 Base plate 8 Copper plate 9 Polyimide resin DESCRIPTION OF SYMBOLS 10 Adhesive 11 Magnesium oxide base material 12 First electrode 13 PZT thin film 14 Second electrode 15 Thin film piezoelectric material 16 Photosensitive polyimide 17A Terminal hole 17B Opening 18A, 18B Lead wire 19 Lead 20 First wiring pattern 20A to D Wiring line 21 2nd wiring pattern 21A D wiring line 22A~D slider connection terminal 23A~D thin-film piezoelectric element connection terminal 24A~H external connection terminal 25 Epoxy resin 26 Suspension

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01L 41/09 H02N 2/00 B 41/18 H01L 41/08 U 41/22 41/18 101Z H02N 2/00 41 / 22 Z (72) Inventor Kaoru Matsuoka 1006 Kazuma, Kadoma, Osaka Pref.F-term (reference) in Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] In a head support mechanism in which a head for reproducing at least data on a rotationally driven disk is supported on a support portion of a substrate, a thin-film piezoelectric element provided on the support portion provides the head support mechanism. A thin-film piezoelectric actuator for a disk device for displacing a head by deforming a supporting portion of a substrate, wherein the thin-film piezoelectric element has electrodes on both surfaces of the thin-film piezoelectric and reaches from one electrode to the other electrode. A thin-film piezoelectric actuator having a terminal hole, a lead wire connected to the other electrode is provided inside the terminal hole, and is drawn out to one electrode side. 2. The device according to claim 1, wherein the head is disposed between the tips of the support portions of the substrate which are arranged in parallel with each other, and the thin film piezoelectric element is provided on each of the support portions. Thin film piezoelectric actuator. 3. The thin-film piezoelectric element has a warpage of 400 μm or less when no head is mounted between the support portions of the substrate and no voltage is applied. 2. The thin film piezoelectric actuator according to item 1. 4. A 5 μm metal plate is provided on each support of the substrate, and each of the thin film piezoelectric elements provided on each support has a length of 5 mm or less in the direction of expansion and contraction. The thin film piezoelectric actuator according to claim 2. 5. A head support mechanism in which a head for performing at least data reproduction on a rotationally driven disk is supported on a support portion of a substrate, wherein the thin film piezoelectric element provided on the support portion provides the head support mechanism. What is claimed is: 1. A method for manufacturing a thin film piezoelectric actuator for a disk device for displacing a head by deforming a supporting portion of a substrate, comprising the steps of: forming a thin film piezoelectric on a substrate by a sputtering process; Forming a lead wire by a photolithographic process and an etching process to form a thin-film piezoelectric element; and bonding the formed thin-film piezoelectric element to a substrate while being removed from a substrate. A method for manufacturing a thin-film piezoelectric actuator, comprising: