U.S. patent application number 14/933470 was filed with the patent office on 2017-05-11 for thin-film piezoelectric material element, head gimbal assembly and hard disk drive.
The applicant listed for this patent is SAE Magnetics (H.K.) Ltd.. Invention is credited to Atsushi IIJIMA, Wei XIONG.
Application Number | 20170133045 14/933470 |
Document ID | / |
Family ID | 58644137 |
Filed Date | 2017-05-11 |
United States Patent
Application |
20170133045 |
Kind Code |
A1 |
XIONG; Wei ; et al. |
May 11, 2017 |
THIN-FILM PIEZOELECTRIC MATERIAL ELEMENT, HEAD GIMBAL ASSEMBLY AND
HARD DISK DRIVE
Abstract
A thin-film piezoelectric material element includes a laminated
structure part having a lower electrode film, a piezoelectric
material film laminated on the lower electrode film and an upper
electrode film laminated on the piezoelectric material film. The
thin-film piezoelectric material element includes a surface layer
insulating film disposed on side surfaces of the laminated
structure part and a top surface of the upper electrode film, and
has a through hole formed on a top disposed part disposed on the
top surface. The surface layer insulating film has a long-side
disposed part disposed outside than the top disposed part, the
long-side disposed part has a long-side width, along with the
long-side direction, formed shorter than the through hole.
Inventors: |
XIONG; Wei; (Hong Kong,
CN) ; IIJIMA; Atsushi; (Hong Kong, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAE Magnetics (H.K.) Ltd. |
Hong Kong |
|
CN |
|
|
Family ID: |
58644137 |
Appl. No.: |
14/933470 |
Filed: |
November 5, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 41/0986 20130101;
G11B 5/483 20150901; H01L 41/0475 20130101 |
International
Class: |
G11B 5/48 20060101
G11B005/48; H01L 41/047 20060101 H01L041/047 |
Claims
1. A thin-film piezoelectric material element comprising: a
laminated structure part comprising a lower electrode film, a
piezoelectric material film laminated on the lower electrode film
and an upper electrode film laminated on the piezoelectric material
film; a surface layer insulating film disposed on side surfaces of
the laminated structure part and a top surface of the upper
electrode film, and has a through hole formed on a top disposed
part disposed on the top surface; and an upper electrode pad being
in directly contact with an inside exposed surface, exposed inside
the through hole, of the upper electrode film; wherein the upper
electrode pad arranged entirely inside an outer edge part of the
top disposed part, and formed without contact with a side disposed
part, formed along with side surfaces of the laminated structure
part, of the surface layer insulating film.
2. The thin-film piezoelectric material element according to claim
1, wherein the upper electrode pad has a long pad-length along with
a long-side direction of the thin-film piezoelectric material
element and a short pad-length along with a short-side direction of
the thin-film piezoelectric material element, wherein the long
pad-length is shorter than the short pad-length.
3. The thin-film piezoelectric material element according to claim
1, wherein the upper electrode pad has an outer end surface formed
outside than the top disposed part, wherein the outer end surface
is formed entirely flat, and disposed inside than the outer edge
part of the top disposed part.
4. The thin-film piezoelectric material element according to claim
1, wherein the surface layer insulating film has a long-side
disposed part disposed outside than the top disposed part along
with a long-side direction of the thin-film piezoelectric material
element, wherein the long-side disposed part has a long-side width,
along with the long-side direction, formed shorter than the through
hole.
5. The thin-film piezoelectric material element according to claim
4, wherein the inside exposed surface has a non pad-contact
surface, formed partially, being out of contact with the upper
electrode pad.
6. The thin-film piezoelectric material element according to claim
5, wherein the upper electrode pad is formed smaller than the
inside exposed surface, wherein the non pad-contact surface is
formed so as to surround the upper electrode pad.
7. The thin-film piezoelectric material element according to claim
3, wherein the outer end surface is disposed entirely inside the
through hole.
8. The thin-film piezoelectric material element according to claim
3, wherein the outer end surface has an extended part disposed
outside than the through hole, wherein the extended part is
disposed inside than the outer edge part of the top disposed
part.
9. (canceled)
10. A head gimbal assembly comprising a head slider having a
thin-film magnetic head; a suspension for supporting the head
slider; and a thin-film piezoelectric material element for
displacing the head slider relatively to the suspension; wherein
the thin-film piezoelectric material element comprising: a
laminated structure part comprising a lower electrode film, a
piezoelectric material film laminated on the lower electrode film
and an upper electrode film laminated on the piezoelectric material
film; a surface layer insulating film disposed on side surfaces of
the laminated structure part and a top surface of the upper
electrode film, and has a through hole formed on a top disposed
part disposed on the top surface; and an upper electrode pad being
in directly contact with an inside exposed surface, exposed inside
the through hole, of the upper electrode film; wherein the upper
electrode pad arranged entirely inside an outer edge part of the
top disposed part, and formed without contact with a side disposed
part, formed along with side surfaces of the laminated structure
part, of the surface layer insulating film.
11. The head gimbal assembly according to claim 10, wherein the
upper electrode pad has an outer end surface formed outside than
the upper disposed part, wherein the outer end surface is formed
entirely flat, and disposed inside than the outer edge part of the
top disposed part, wherein the head gimbal assembly further
comprising: a suspension pad formed on the suspension; and a
connecting electrode which connects the outer end surface with the
suspension pad.
12.-13. (canceled)
14. A hard disk drive comprising a head gimbal assembly including a
head slider having a thin-film magnetic head, a suspension for
supporting the head slider, a thin-film piezoelectric material
element for displacing the head slider relatively to the
suspension; and a recording medium; wherein the thin-film
piezoelectric material element comprising: a laminated structure
part comprising a lower electrode film, a piezoelectric material
film laminated on the lower electrode film and an upper electrode
film laminated on the piezoelectric material film; a surface layer
insulating film disposed on side surfaces of the laminated
structure part and a top surface of the upper electrode film, and
has a through hole formed on a top disposed part disposed on the
top surface; and an upper electrode pad being in directly contact
with an inside exposed surface, exposed inside the through hole, of
the upper electrode film; wherein the upper electrode pad arranged
entirely inside an outer edge part of the top disposed part, and
formed without contact with a side disposed part, formed along with
side surfaces of the laminated structure part, of the surface layer
insulating film.
15.-16. (canceled)
Description
BACKGROUND
[0001] Field of the Invention
[0002] The present invention relates to a thin-film piezoelectric
material element which has a piezoelectric material and electrodes
having thin-film like shape, head gimbal assembly and hard disk
drive having the thin-film piezoelectric material element.
[0003] Related Background Art
[0004] A hard disk drive has a large recording capacity and is used
as the heart of a storage device. The hard disk drive records and
reproduces data to/from a hard disk (recording medium) by a
thin-film magnetic head. A part, which the thin-film magnetic head
is formed, is called as a head slider, and a part, which the head
slider is mounted on the edge part, is a head gimbal assembly (will
also be referred to as HGA).
[0005] Further, recording and reproducing of data to/from the
recording medium is performed by flying the head slider from a
surface of the recording medium while rotating the recording
medium, in the hard disk drive.
[0006] On the other hand, it has become difficult to control a
position of the thin-film magnetic head accurately by control with
only a voice coil motor (VCM), because heightening a recording
density of the recording medium has developed in company with
increase of a capacity of the hard disk drive. Therefore formerly,
a technology, which an actuator having supplementary function (a
supplementary actuator) is mounted on the HGA in addition to a main
actuator with the VCM, and the supplementary actuator controls a
minute position that is not able to be controlled by the VCM, is
known.
[0007] A technology, which the main actuator and the supplementary
actuator control the position of the thin-film magnetic head, is
also called two stage actuator system (dual-stage system).
[0008] In the two stage actuator system, the main actuator makes
drive arms rotate to decide a position of the head slider on a
specific track of the recording medium. Further, the supplementary
actuator adjusts the position of the head slider minutely so that
the position of the thin-film magnetic head may become an optimum
position.
[0009] A micro actuator using a thin-film piezoelectric material
element is known formerly as the supplementary actuator. The
thin-film piezoelectric material element has a piezoelectric
material and a pair of electrodes formed to sandwich the
piezoelectric material, and each of them is formed to be a
thin-film shape.
[0010] Further, a technology, which displacement stroke of the
element is increased to increase the displacement control amount of
the magnetic head, is conventionally known (for example, see U.S.
Pat. No. 8,885,294 (referred also to as Patent Document 1)). The
HGA having a following structure is disclosed in the patent
document 1. The HGA has the structure which the piezoelectric
material element is fixed to the bottom of concave part formed on a
gimbal part. It is possible to prevent the stroke of expansion or
shrinking of the thin-film piezoelectric material element from
escaping in a curved direction, thereby the displacement stroke of
thin-film piezoelectric material element increase.
[0011] On the other hand, to avoid electrical shorting between the
upper electrode film and the lower electrode film, the
piezoelectric material element, which the insulating layer made of
oxide or poly-imide are formed to wrap on the top surface and side
surfaces of four direction of piezoelectric material, is known (for
example, see U.S. Pat. No. 6,931,700 (referred to also as Patent
Document 2), U.S. Pat. No. 7,006,334 (referred to also as Patent
Document 3)). An opening of the insulating layer is formed on the
top surface of the piezoelectric material so that the top surface
of the piezoelectric material is exposed, in these thin-film
piezoelectric material elements. Further, the HGA, having a flexure
including a structure with the piezoelectric element, is disclosed
in JP 2014-106985 (referred to also as Patent Document 4). The
thin-film piezoelectric material element is fixed to the flexure,
in the HGA.
SUMMARY OF THE INVENTION
[0012] As mentioned in the above-described Patent Documents 2-3,
thin-film piezoelectric material elements having a structure, which
the opening (or via hole) is formed in the insulating layer for
securing electrical conduction with piezoelectric material, and an
electrode layer is formed on the opening (referred to also as
"opening and electrode structure"), is known. The electrode layer
is extended from the opening to the outside of the thin-film
piezoelectric material element along with the surface of the
insulating layer, for securing electrical connection with the
outside and electrical supply from the outside, in thin-film
piezoelectric material elements disclosed in these documents.
[0013] By the way, if an area for mounting the thin-film
piezoelectric material element is secured widely in the HGA, an
area for mounting the opening and electrode (referred to also as
"opening and electrode area") is able to be secured even which side
of an area along with the width direction of piezoelectric material
(referred to also as "width direction area") and an area along with
the length direction of piezoelectric material (referred to also as
"length direction area").
[0014] In this case, because the piezoelectric material expands and
shrinks along with the length direction, if the opening and
electrode area is secured in the width direction area, it does not
affect length of the piezoelectric material, and it does not affect
expanding and shrinking motion of the piezoelectric material.
Therefore, it is preferable that the opening and electrode area is
secured in the width direction area.
[0015] However, a space for accommodating the opening and electrode
layer is not able to be secured in the width direction area of the
HGA. Therefore, the opening and electrode area needs to be secured
in the length direction area.
[0016] If the electrode layer is extended along with length
direction of the piezoelectric material, it needs shortening of
length of the piezoelectric material. In this case, extension of
the electrode layer affects expanding and shrinking motion of the
piezoelectric material.
[0017] On the other hand, concerning a pair of the thin-film
piezoelectric material elements, from reliability point of view, it
is necessary to keep opening and electrode layer not moving while
the other thin-film piezoelectric material element expands and
shrinks under the driving voltages. This can be done by make the
piezoelectric material elements inactive by overlapping with parts
having strong mechanical strength such as stainless substrate.
[0018] Further, in case of the thin-film piezoelectric material
element overlapped on the stainless substrate, a stroke for
expanding and shrinking motion of the thin-film piezoelectric
material element is proportional to the length of thin-film
piezoelectric material element without overlapping with the
stainless substrate, defined as "active length". Extension of the
active length causes increase of the stroke. Accordingly, it is
always the goal to design active thin-film piezoelectric material
element with active length as longer as possible.
[0019] However, the opening and electrode area is secured in the
length direction area, in case of the conventional thin-film
piezoelectric material element having the opening and electrode
structure. Therefore, the active length is limited by the length of
total thin-film piezoelectric material element minus length of the
opening and electrode area. Further, in accordance with increasing
size of the opening and needed electrode layer length, it brings
more difficulty about extending of the active length of the
thin-film piezoelectric material element.
[0020] The present invention is made to solve the above problem,
and it is an object to extend the active length, and increase the
stroke while having the opening and electrode structure positioned
in a long-side direction, in the thin-film piezoelectric material
element, head gimbal assembly and hard disk drive.
[0021] To solve the above problem, the present invention is a
thin-film piezoelectric material element including: a laminated
structure part including a lower electrode film, a piezoelectric
material film laminated on the lower electrode film and an upper
electrode film laminated on the piezoelectric material film; a
surface layer insulating film disposed on side surfaces of the
laminated structure part and a top surface of the upper electrode
film, and has a through hole formed on a top disposed part disposed
on the top surface; and an upper electrode pad being in directly
contact with an inside exposed surface, exposed inside the through
hole, of the upper electrode film; the upper electrode pad arranged
entirely inside an outer edge part of the top disposed part, and
formed without contact with a side disposed part, formed along with
side surfaces of the laminated structure part, of the surface layer
insulating film.
[0022] In case of the above-described thin-film piezoelectric
material element, because the upper electrode pad is arranged
entirely inside the outer edge part of the top disposed part, and
formed without contact with the side disposed part, larger space
than the conventional one is secured in the long-side direction of
the thin-film piezoelectric material element.
[0023] Further, in case of the above-described thin-film
piezoelectric material element, it is preferable that the upper
electrode pad has a long pad-length along with a long-side
direction of the thin-film piezoelectric material element and a
short pad-length along with a short-side direction of the thin-film
piezoelectric material element, the long pad-length is shorter than
the short pad-length.
[0024] Further, the upper electrode pad has an outer end surface
formed outside than the top disposed part, the outer end surface is
formed entirely flat, and disposed inside than the outer edge part
of the top disposed part.
[0025] It is preferable that the surface layer insulating film has
a long-side disposed part disposed outside than the top disposed
part along with a long-side direction of the thin-film
piezoelectric material element, the long-side disposed part has a
long-side width, along with the long-side direction, formed shorter
than the through hole.
[0026] Furthermore, the inside exposed surface has a non
pad-contact surface, formed partially, being out of contact with
the upper electrode pad.
[0027] It is possible that the upper electrode pad is formed
smaller than the inside exposed surface, the non pad-contact
surface is formed so as to surround the upper electrode pad.
[0028] Further, it is possible that the outer end surface is
disposed entirely inside the through hole.
[0029] It is preferable that the outer end surface has an extended
part disposed outside than the through hole, the extended part is
disposed inside than the outer edge part of the top disposed
part.
[0030] Further, the present invention provides a thin-film
piezoelectric material element including: a laminated structure
part including a lower electrode film, a piezoelectric material
film laminated on the lower electrode film and an upper electrode
film laminated on the piezoelectric material film; and a surface
layer insulating film disposed on side surfaces of the laminated
structure part and a top surface of the upper electrode film, and
has a through hole formed on a top disposed part disposed on the
top surface; the surface layer insulating film has a long-side
disposed part disposed outside than the top disposed part along
with a long-side direction of the thin-film piezoelectric material
element, the long-side disposed part has a long-side width, along
with the long-side direction, formed shorter than the through
hole.
[0031] Further, the present invention provides a head gimbal
assembly including a head slider having a thin-film magnetic head;
a suspension for supporting the head slider; and a thin-film
piezoelectric material element for displacing the head slider
relatively to the suspension; the thin-film piezoelectric material
element including: a laminated structure part including a lower
electrode film, a piezoelectric material film laminated on the
lower electrode film and an upper electrode film laminated on the
piezoelectric material film; a surface layer insulating film
disposed on side surfaces of the laminated structure part and a top
surface of the upper electrode film, and has a through hole formed
on a top disposed part disposed on the top surface; and an upper
electrode pad being in directly contact with an inside exposed
surface, exposed inside the through hole, of the upper electrode
film; the upper electrode pad arranged entirely inside an outer
edge part of the top disposed part, and formed without contact with
a side disposed part, formed along with side surfaces of the
laminated structure part, of the surface layer insulating film.
[0032] In case of the above-described head gimbal assembly, it is
preferable that the upper electrode pad has an outer end surface
formed outside than the upper disposed part, the outer end surface
is formed entirely flat, and disposed inside than the outer edge
part of the top disposed part, the head gimbal assembly further
including: a suspension pad formed on the suspension; and a
connecting electrode which connects the outer end surface with the
suspension pad.
[0033] Further, the present invention provides a head gimbal
assembly including a head slider having a thin-film magnetic head;
a suspension for supporting the head slider; and a thin-film
piezoelectric material element for displacing the head slider
relatively to the suspension; the thin-film piezoelectric material
element including: a laminated structure part including a lower
electrode film, a piezoelectric material film laminated on the
lower electrode film and an upper electrode film laminated on the
piezoelectric material film; and a surface layer insulating film
disposed on side surfaces of the laminated structure part and a top
surface of the upper electrode film, and has a through hole formed
on a top disposed part disposed on the top surface; the surface
layer insulating film has, a long-side disposed part disposed
outside than the top disposed part along with a long-side direction
of the thin-film piezoelectric material element, the long-side
disposed part has a long-side width, along with the long-side
direction, formed shorter than the through hole.
[0034] In the above-described head gimbal assembly, it is
preferable that the head gimbal assembly, further including: a
suspension pad formed on the suspension; and a connecting electrode
which connects an inside exposed surface, exposed inside the
through hole of the upper electrode film, with the suspension
pad.
[0035] Further, the present invention provides a hard disk drive
including a head gimbal assembly including a head slider having a
thin-film magnetic head, a suspension for supporting the head
slider, a thin-film piezoelectric material element for displacing
the head slider relatively to the suspension; and a recording
medium; the thin-film piezoelectric material element including: a
laminated structure part including a lower electrode film, a
piezoelectric material film laminated on the lower electrode film
and an upper electrode film laminated on the piezoelectric material
film; surface layer insulating film disposed on side surfaces of
the laminated structure part and a top surface of the upper
electrode film, and has a through hole formed on a top disposed
part disposed on the top surface; and an upper electrode pad being
in directly contact with an inside exposed surface, exposed inside
the through hole, of the upper electrode film; the upper electrode
pad arranged entirely inside an outer edge part of the top disposed
part, and formed without contact with a side disposed part, formed
along with side surfaces of the laminated structure part, of the
surface layer insulating film.
[0036] Further, the present invention provides a hard disk drive
including a head gimbal assembly including a head slider having a
thin-film magnetic head, a suspension for supporting the head
slider, a thin-film piezoelectric material element for displacing
the head slider relatively to the suspension; and a recording
medium; the thin-film piezoelectric material element including: a
laminated structure part including a lower electrode film, a
piezoelectric material film laminated on the lower electrode film
and an upper electrode film laminated on the piezoelectric material
film; and a surface layer insulating film disposed on side surfaces
of the laminated structure part and a top surface of the upper
electrode film, and has a through hole formed on a top disposed
part disposed on the top surface; the surface layer insulating film
has a long-side disposed part disposed outside than the top
disposed part along with a long-side direction of the thin-film
piezoelectric material element, the long-side disposed part has a
long-side width, along with the long-side direction, formed shorter
than the through hole.
[0037] In case of the above-described hard disk drive, it is
preferable that the hard disk drive further including: a suspension
pad formed on the suspension; and a connecting electrode which
connects an inside exposed surface, exposed inside the through hole
of the upper electrode film, with the suspension pad.
[0038] The present invention will be more fully understood from the
detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus are
not to be considered as limiting the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] FIG. 1 is a perspective view showing a whole of the HGA,
from front side, according to an embodiment of the present
invention;
[0040] FIG. 2 is a perspective view showing, from front side, a
principal part of the HGA in FIG. 1;
[0041] FIG. 3 is a perspective view showing a principal part of a
suspension constituting the HGA in FIG. 1 from front side;
[0042] FIG. 4 is a perspective view showing a part, which a
thin-film piezoelectric material element is fixed, of flexure with
enlargement;
[0043] FIG. 5 is a plan view showing the thin-film piezoelectric
material element and the peripheral part of the HGA in FIG. 1;
[0044] FIG. 6 is a sectional view taken along the line 6-6 in FIG.
5;
[0045] FIG. 7 is a sectional view taken along the line 7-7 in FIG.
5;
[0046] FIG. 8 is a sectional view, similar with FIG. 6, showing the
thin-film piezoelectric material element connected to a suspension
pad by a connecting electrode;
[0047] FIG. 9 is a plan view, similar with FIG. 5, showing the
thin-film piezoelectric material element and the peripheral part
according to modified example;
[0048] FIG. 10 is a sectional view taken along the line 10-10 in
FIG. 9;
[0049] FIG. 11 is a sectional view taken along the line 11-11 in
FIG. 9;
[0050] FIG. 12 is a sectional view, similar with FIG. 6, showing
the thin-film piezoelectric material element, according to the
modified example, connected to the suspension pad by the connecting
electrode;
[0051] FIG. 13 is a plan view, similar with FIG. 5, showing the
thin-film piezoelectric material element and the peripheral part
according to another modified example;
[0052] FIG. 14 is a sectional view taken along the line 14-14 in
FIG. 13;
[0053] FIG. 15 is a sectional view taken along the line 15-15 in
FIG. 13;
[0054] FIG. 16 is a sectional view, similar with FIG. 14, showing
the thin-film piezoelectric material element, according to another
modified example, connected to the suspension pad by the connecting
electrode;
[0055] FIG. 17 is a plan view, similar with FIG. 5, showing the
thin-film piezoelectric material element and the peripheral part
according to still another modified example;
[0056] FIG. 18 is a sectional view taken along the line 18-18 in
FIG. 17;
[0057] FIG. 19 is a sectional view taken along the line 19-19 in
FIG. 17;
[0058] FIG. 20 is a sectional view, similar with FIG. 19, showing
the thin-film piezoelectric material element, according to still
another modified example, connected to the suspension pad by the
connecting electrode;
[0059] FIG. 21 (a) is a sectional view showing a principal part of
the conventional thin-film piezoelectric material element, FIG. 21
(b) is a sectional view showing a principal part of another
conventional thin-film piezoelectric material element;
[0060] FIG. 22 (a) is a view schematically showing stroke of the
thin-film piezoelectric material element in FIG. 21 (a), FIG. 22
(b) is a view schematically showing stroke of the thin-film
piezoelectric material element in FIG. 21 (b);
[0061] FIG. 23 (a) is a plan view showing the thin-film
piezoelectric material elements according to the embodiment of the
present embodiment, FIG. 23 (b) is a plan view showing the
conventional thin-film piezoelectric material element;
[0062] FIG. 24 is a plan view showing the thin-film piezoelectric
material element and the peripheral part in the conventional
HGA;
[0063] FIG. 25 is a sectional view taken along the line 25-25 in
FIG. 24;
[0064] FIG. 26 is a sectional view, similar with FIG. 25, showing
the thin-film piezoelectric material element in FIG. 24 connected
to the suspension pad by the connecting electrode; and
[0065] FIG. 27 is a perspective view showing a hard disk drive
equipped with the HGA according to the embodiment of the present
invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0066] In the following, embodiments of the present invention will
be described with reference to the drawings. Note that the same
components will be referred to with the same numerals or letters,
while omitting their overlapping descriptions.
[0067] (Structure of HGA)
[0068] To begin with, a structure of the HGA according to the
embodiment of the present invention will be explained with
reference to FIG. 1 to FIG. 4. Here, FIG. 1 is a perspective view
showing a whole of the HGA 1, from front side, according to an
embodiment of the present invention. FIG. 2 is a perspective view
showing a principal part of the HGA 1 from front side. FIG. 3 is a
perspective view showing a principal part of the suspension 50
constituting the HGA 1 from front side. Further, FIG. 4 is a
perspective view showing a part, which a thin-film piezoelectric
material element 12b is fixed, of a flexure 6 with enlargement.
[0069] As illustrated in FIG. 1, the HGA 1 has the suspension 50
and a head slider 60. The suspension 50 has a base plate 2, a load
beam 3, the flexure 6 and a dumper not illustrated, and it has a
structure which these parts are joined to be united one body by a
weld and so on.
[0070] The base plate 2 is a part which is used to fix the
suspension 50 to a drive arms 209 of a later-described hard disk
drive 201, and it is formed with a metal such as stainless steel or
the like.
[0071] The load beam 3 is fixed on the base plate 2. The load beam
3 has a shape in which the width gradually decreases as it is
distanced more from the base plate 2. The load beam 3 has a load
bending part which generates a power for pressing the head slider
60 against the later-described hard disk 202 of the hard disk drive
201.
[0072] Further, as illustrated in FIG. 1 to FIG. 4, the flexure 6
has a flexure substrate 4, a base insulating layer 5, a connecting
wiring 11 and thin-film piezoelectric material elements 12a, 12b.
The flexure 6 has a structure which the base insulating layer 5 is
formed on the flexure substrate 4, the connecting wiring 11 and
thin-film piezoelectric material elements 12a, 12b are adhered on
the base insulating layer 5. Further, the not illustrated
protective insulating layer is formed so as to cover the connecting
wiring 11 and thin-film piezoelectric material elements 12a,
12b.
[0073] The flexure 6 has a piezoelectric elements attached
structure which thin-film piezoelectric material elements 12a, 12b
are fixed on the surface of the base insulating layer 5 in addition
to the connecting wiring 11 to become a structure with
piezoelectric element.
[0074] Further, the flexure 6 has a gimbal part 10 on the tip side
(load beam 3 side). A tongue part 19, which the head slider 60 is
mounted, is secured on the gimbal part 10, and a plurality of
connecting pads 20 are formed near an edge side than the tongue
part 19. Connecting pads 20 are electrically connected to
not-illustrated electrode pads of the head slider 60.
[0075] This flexure 6 expands or shrinks thin-film piezoelectric
material elements 12a, 12b and expands or shrinks stainless part
(referred to out trigger part) jut out outside of the tongue part
19. That makes a position of the head slider 60 move very slightly
around not-illustrated dimple, and a position of the head slider 60
is controlled minutely.
[0076] The flexure substrate 4 is a substrate for supporting a
whole of the flexure 6, and it is formed with stainless. Rear side
of the flexure substrate 4 is fixed to the base plate 2 and the
load beam 3 by weld. As illustrated in FIG. 1, the flexure
substrate 4 has a center part 4a fixed to surfaces of the load beam
3 and the base plate 2, and a wiring part 4b extending to outside
from the base plate 2.
[0077] The base insulating layer 5 covers s surface of the flexure
substrate 4. The base insulating layer 5 is formed with for example
polyimide, and it has a thickness of about 5 .mu.m to 10 .mu.m.
Further, as illustrated in detail in FIG. 3, a part of the base
insulating layer 5, disposed on the load beam 3, is divided two
parts. One part of them is a first wiring part 5a, the other part
of them is second wiring part 5b. The thin-film piezoelectric
material element 12a and thin-film piezoelectric material element
12b are adhered on surfaces of each wiring part.
[0078] A plurality of connecting wirings 11 are formed on surfaces
of each of the first wiring part 5a and the second wiring part 5b.
Each connecting wiring 11 is formed with conductor such as copper
or the like. One end parts of each connecting wiring 11 are
connected to the thin-film piezoelectric material elements 12a, 12b
or each connecting pad 20.
[0079] The not-illustrated protective insulating layer is formed
with for example polyimide. The protective insulating layer has a
thickness of about 1 .mu.m to 2 .mu.m, for example.
[0080] Further, a not illustrated thin-film magnetic head, which re
records and reproduces data, is formed on the head slider 60.
Furthermore, a plurality of not illustrated electrode pads are
formed on the head slider 60, and each electrode pad is connected
to the connecting pad 20.
[0081] (Structure of Thin-Film Piezoelectric Material Element)
[0082] Subsequently, the structure of thin-film piezoelectric
material element 12b will be explained with reference to FIG. 5 to
FIG. 8. Here, FIG. 5 is a plan view showing the thin-film
piezoelectric material element 12b and the peripheral part of the
HGA 1. FIG. 6 is a sectional view taken along the line 6-6 in FIG.
5, FIG. 7 is a sectional view taken along the line 7-7 in FIG. 5.
FIG. 8 is a sectional view, similar with FIG. 6, showing the
thin-film piezoelectric material element 12b connected to a
suspension pad 26 by a connecting electrode 18b. Note that the
connecting electrode 18b is omitted in FIGS. 5-7 for convenience of
illustration.
[0083] The thin-film piezoelectric material element 12b (similar to
thin-film piezoelectric material element 12a), as illustrated in
FIG. 5-FIG. 8, has a laminated structure part 21, a surface layer
insulating film 22, an upper electrode pad 24A and a lower
electrode pad 24B.
[0084] The thin-film piezoelectric material elements 12b, 12a are
adhered to the surface of the base insulating layer 5 with epoxy
resin. A resin layer 28 made of the epoxy resin is formed between
the laminated structure part 21 and the base insulating layer
5.
[0085] The thin-film piezoelectric material elements 12b is formed
with a rectangular shape in a plan view, as illustrated in detail
in FIG. 5. A pad region 25 is secured at one side along with a
long-side direction of the thin-film piezoelectric material
elements 12b. The pad region 25 is a region from a boundary line
22e of a later-described top disposed part 22a and a side disposed
part 22b to an upper electrode pad 24A and a lower electrode pad
24B. The upper through hole 23A, lower through hole 23B, the upper
electrode pad 24A and lower electrode pad 24B are formed in the pad
region 25.
[0086] Note that "upper" and "lower" in the present invention do
not show necessarily upper side, lower side in a condition which
the thin-film piezoelectric material element is adhered on the base
insulating layer 5. These words are terms for reasons of
convenience so as to distinguish two upper, lower electrode films
21b, 21c and so on opposing each other sandwiching the
piezoelectric material film 21a their between. In the actual
products, the upper electrode film 21b is sometimes disposed lower
side, and the lower electrode film 21c is sometimes disposed upper
side.
[0087] The laminated structure part 21 has the piezoelectric
material film 21a, the lower electrode film 21c and the upper
electrode film 21b. The piezoelectric material film 21a is
laminated on the lower electrode film 21c, the upper electrode film
21b is laminated on the piezoelectric material film 21a. The
laminated structure part 21 has laminated structure formed of the
piezoelectric material film 21a, the lower electrode film 21c and
the upper electrode film 21b.
[0088] The piezoelectric material film 21a is formed to be a
thin-film shape using a piezoelectric material such as lead
zirconate titanate ((Pb (Zr,Ti) O.sub.3) which will also be
referred to as "PZT" in the following) or the like. The
piezoelectric material film 21a is formed by epitaxial growth and
it has a thickness of about 2 .mu.m to 5 .mu.m. A piezoelectric
ceramics (much of them are ferroelectric substance) such as barium
titanate, lead titanate or the like, non-lead system piezoelectric
ceramics not including titanium or lead are able to be used for the
piezoelectric material film 21a instead of using PZT.
[0089] The lower electrode film 21c is a thin-film (thickness about
100 nm) made of metal element which has Pt (it may include Au, Ag,
Pd, Ir, Ru, Cu, in addition to Pt) as main ingredient, it is formed
on the base insulating layer 5. A crystal structure of the lower
electrode film 21 is a face-centered cubic structure.
[0090] Note that a lower adhesive film is preferably formed between
the lower electrode film 21c and the piezoelectric material film
21a, not illustrated though. The lower adhesive film is a thin-film
(thickness about 20 nm) made of conductive material formed by
epitaxial growth such as SrRuO.sub.3 (referred to also as SRO) or
the like, it is able to be formed on top surface, of the lower
electrode film 21c, of the piezoelectric material film 21a side.
The piezoelectric material film 21a is able to be formed on the
lower adhesive film.
[0091] The upper electrode film 21b is a polycrystal thin-film
(thickness about 50 nm) with metal element which has Pt (it may
include Au, Ag, Pd, Ir, Rh, Ni, Pb, Ru, Cu, in addition to Pt) as
main ingredient, it is formed on the piezoelectric material film
21a. The upper electrode film 21b has a figure which the part under
the lower through hole 23B and the peripheral part are lacked
(hereinafter, referred also to as "partial lacked figure), so as
not to be in touch with later-described lower electrode pad
24B.
[0092] Further, not illustrated though, an upper adhesive film is
preferably formed between the piezoelectric material film 21a and
the upper electrode film 21b. The upper adhesive film is a
thin-film (thickness about 35 nm) made of amorphous conductive
material such as SrRuO.sub.3 or the like, and it is formed on the
piezoelectric material film 21a.
[0093] The surface layer insulating film 22 is disposed on the top
surface and side surfaces of four direction of the laminated
structure part 21, and it is formed so as to cover the top surface
and side surfaces of four direction of the laminated structure part
21. The surface layer insulating film 22 is formed with insulating
material such as polyimide or the like. The surface layer
insulating film 22 has a top disposed part 22a, a side disposed
part 22b, and a long-side disposed part 22c.
[0094] The top disposed part 22a is a part disposed on the top
surface of laminated structure part 21. The top disposed part 22a
is formed directly on the top surface 21ba of the upper electrode
film 21b. One end side of the long-side direction of the top
disposed part 22a is assigned to the pad region 25.
[0095] The side disposed part 22b is a part disposed on a long-side
side surfaces of the laminated structure part 21. The long-side
side surfaces are a pair of side surfaces along the long-side
direction of the thin-film piezoelectric material element 12b among
four side surfaces. The side disposed parts 22b are formed directly
on the long-side side surfaces of the laminated structure part 21.
The long-side disposed parts 22c are connected to the lower end
part of the side disposed parts 22b.
[0096] The long-side disposed parts 22c is a part projected outside
from the side disposed parts 22b along the long-side direction. The
long-side disposed parts 22c is formed directly on the base
insulating layer 5. A length of the long-side disposed parts 22c
along the long-side direction (hereinafter, referred also to as
"long-side length") L22c is shorter than later-described long-side
length L23 (L22c<L23). Therefore, in the thin-film piezoelectric
material element 12b, the side disposed parts 22b are brought near
to later-described suspension pad 26 though, even so the long-side
disposed parts 22c is not in contact with the suspension pad
26.
[0097] The upper through hole 23A is formed in the pad region 25 of
the top disposed part 22a. The upper through hole 23A penetrates
the top disposed part 22a, as illustrated in FIG. 6. The top
surface of the upper electrode film 21b is exposed, inside the
upper through hole 23A, as an inside exposed surface 21bb having
rectangular shape in a plan view.
[0098] The lower through hole 23B is also formed in the pad region
25 of the top disposed part 22a. The lower through hole 23B
penetrates the top disposed part 22a similar with the upper through
hole 23A, as illustrated in FIG. 7. Because the upper electrode
film 21b is formed with above-described partial lacked figure,
surface of the piezoelectric material film 21a is exposed, inside
the lower through hole 23B, as an inside exposed surface 21aa
having rectangular shape in a plan view.
[0099] The upper electrode pad 24A is formed inside the upper
through hole 23A. The upper electrode pad 24A is formed in a
rectangular parallelepiped shape. The upper electrode pad 24A is in
directly contact with the inside exposed surface 21bb which is a
surface of the upper electrode film 21b. The upper electrode pad
24A is entirely disposed inside an outer edge part 22d (outermost
peripheral part of the top disposed part 22a). Further, the upper
electrode pad 24A is formed without contact with the side disposed
parts 22b.
[0100] Then, the upper electrode pad 24A has a long-pad length L24
and a short-pad length W24. The long-pad length L24 is a length of
the upper electrode pad 24A along with long-side direction of the
thin-film piezoelectric material element 12b. The short-pad length
W24 is a length of the upper electrode pad 24A along with
short-side direction of the thin-film piezoelectric material
element 12b. Further, the long-pad length L24 is shorter than the
short-pad length W24 (L24<W24).
[0101] Further, the upper electrode pad 24A has an outer end
surface 24AS having rectangular shape in a plan view. A fine mesh
pattern is drawn in the outer end surface 24AS, as illustrated in
FIG. 5. The outer end surface 24AS is formed outside the top
disposed part 22a, as illustrated in FIG. 6. The outer end surface
24AS is entirely flat. The outer end surface 24AS is disposed
inside the outer edge part 22d, and disposed inside the upper
through hole 23A. Note that rough mesh pattern is drawn in the
suspension pad 26, in FIG. 5.
[0102] Furthermore, the upper electrode pad 24A is formed in a size
smaller than the inside exposed surface 21bb. A gap is secured
between the upper electrode pad 24A and inside side surface of the
upper through hole 23A. And, a part of the inside exposed surface
21bb is a non pad-contact surface being out of contact with the
upper electrode pad 24A. The non pad-contact surface is formed in a
circular shape which surrounds periphery of the upper electrode pad
24A.
[0103] The lower electrode pad 24B has an upper pad part 24Ba and a
lower pad part 24Bb, as illustrated in FIG. 7. The upper pad part
24Ba is connected with the top surface of the lower pad part 24Bb.
The upper pad part 24Ba and the lower pad part 24Bb are formed in
the rectangular parallelepiped shape respectively.
[0104] The upper pad part 24Ba is formed inside the lower through
hole 23B. The upper pad part 24Ba is entirely disposed inside the
outer edge part 22d similar with the upper electrode pad 24A.
Further, the upper pad part 24Ba is formed without contact with the
side disposed parts 22b.
[0105] The upper pad part 24Ba has the same long-pad length L24 and
short-pad length W24 as the upper electrode pad 24A. Further, the
upper pad part 24Ba has the same outer end surface 24BS having
rectangular shape in a plan view as the upper electrode pad 24A. As
illustrated in FIG. 5, the same fine mesh pattern is also drawn in
the outer end surface 24BS as the outer end surface 24AS. The outer
end surface 24BS is entirely flat. The outer end surface 24BS is
disposed entirely inside the outer edge part 22d, and disposed
inside the upper through hole 23A.
[0106] Furthermore, the upper pad part 24Ba is formed in a size
smaller than the inside exposed surface 21aa similar with the upper
electrode pad 24A, and the gap is also secured between the upper
pad part 24Ba and inside side surface of the lower through hole
23B. And, a part of the inside exposed surface 21aa is formed the
non pad-contact surface being out of contact with the upper pad
part 24Ba. The non pad-contact surface is formed in a circular
shape which surrounds periphery of the upper pad part 24Ba.
[0107] The lower pad part 24Bb penetrates the piezoelectric
material film 21a. The lower pad part 24Bb is embedded in a hole
part of the piezoelectric material film 21a. The top surface of the
lower pad part 24Bb is exposed in the top surface of the
piezoelectric material film 21a, the upper pad part 24Ba is
connected to the top surface of the lower pad part 24Bb. The lower
pad part 24Bb is directly contact with the top surface of the lower
electrode film 21c.
[0108] The thin-film piezoelectric material elements 12b, having
the above-described structure, is connected to suspension pads 26,
26 with connecting electrode 18b (referred to also connecting pad,
can be formed with solder, for example). In this case, connecting
electrodes 18b, 18b connect outer end surfaces 24AS, 24BS of the
upper, lower electrode pad 24A, 24B to suspension pads 26, 26,
respectively.
[0109] Note that connecting wiring 11 and thin-film piezoelectric
material elements 12b, 12a are shown in FIG. 2 to FIG. 4, for
illustration of convenience, they are not exposed in the surface of
the flexure 6, because they are cover with not-illustrated
protective insulating layer.
[0110] (Operation and Effect of Thin-Film Piezoelectric Material
Element)
[0111] Subsequently, operation and effect of the thin-film
piezoelectric material element 12b having the above-described
structure will be explained with comparing the thin-film
piezoelectric material element 12b according to the embodiment of
the present invention with a conventional thin-film piezoelectric
material element 112b.
[0112] First of all, the conventional thin-film piezoelectric
material element 112b will be explained as follows. The
conventional thin-film piezoelectric material element 112b is shown
in FIG. 24, FIG. 25, FIG. 26. Here, FIG. 24 is a plan view showing
the thin-film piezoelectric material element 112b and the
peripheral part in the conventional HGA. FIG. 25 is a sectional
view taken along the line 25-25 in FIG. 24. FIG. 26 is a sectional
view, similar with FIG. 25, showing the thin-film piezoelectric
material element 112b connected to the suspension pad 26 by the
connecting electrode 118b.
[0113] The conventional thin-film piezoelectric material element
112b has a laminated structure part 121, a surface layer insulating
film 122, an upper electrode pad 124A and a lower electrode pad
124B. The thin-film piezoelectric material elements 112b is adhered
to the surface of the base insulating layer 5 with epoxy resin
similar with the thin-film piezoelectric material element 12b.
Therefore, a resin layer 28 made of the epoxy resin is formed
between the laminated structure part 121 and the base insulating
layer 5.
[0114] The thin-film piezoelectric material elements 112b is formed
with the same rectangular shape with the thin-film piezoelectric
material elements 12b, a pad region 125 is secured in one side
along with a long-side direction of the thin-film piezoelectric
material elements 112b. The pad region 125 is a region from a
boundary line 122e of a later-described top disposed part 122a and
a side disposed part 122b of the surface layer insulating film 122
to upper, lower electrode pads 124A, 124B.
[0115] The laminated structure part 121 has the upper electrode
film 121b, the piezoelectric material film 121a and the lower
electrode film 121c. The laminated structure part 121 has the same
three-layers structure with the laminated structure part 21.
However, the active length ALX is shorter than the active length AL
of the thin-film piezoelectric material elements 12b.
[0116] The surface layer insulating film 122 is different in that
it has a top disposed part 122a, a side disposed part 122b, and a
long-side disposed part 122c as compared with the surface layer
insulating film 22. The top disposed part 122a is a part disposed
on the top surface of laminated structure part 121, the side
disposed part 122b is a part disposed on long-side side surfaces of
the laminated structure part 121, and the long-side disposed parts
122c is a part projected outside from the side disposed parts 122b
along the long-side direction. The long-side length L122c is longer
than later-described long-side length L123 (L122c>L123). The
surface layer insulating film 122 differs from the surface layer
insulating film 22 in this point greatly.
[0117] The upper, lower through holes 123A, 123B are different in
that parts of upper, lower electrode pads 124A, 124B are formed
inside them respectively without gap, as compared with the upper,
lower through holes 23A, 23B. Further, the upper, lower through
holes 123A, 123B are different in that the upper, lower through
holes 123A, 123B are smaller than later-described outer end
surfaces 124AS, 124BS of the upper, lower electrode pad 124A, 124B,
as compared with the upper, lower through holes 23A, 23B.
[0118] The upper, lower electrode pads 124A, 124B are directly in
contact with surfaces of the upper, lower electrode films 121b,
121c respectively as the upper, lower electrode pads 24A, 24B are
directly in contact with surfaces of the upper, lower electrode
films 21b, 21c respectively. However, the upper, lower electrode
pads 124A, 124B and the upper, lower electrode pads 24A, 24B are
different in the following A) to F).
[0119] A) Parts of the upper, lower electrode pads 124A, 124B are
disposed outside an outer edge part 122d of the top disposed part
122a. However, the upper, lower electrode pad 24A, 24B are entirely
disposed inside the outer edge part 22d.
[0120] B) The upper, lower electrode pads 124A, 124B have parts
being in contact with the side disposed parts 122b respectively.
However, the upper, lower electrode pad 24A, 24B are formed without
being contact with the side disposed parts 22b, and they do not
have parts being in contact with the side disposed parts 22b.
[0121] C) Long-pad length L124 of the upper, lower electrode pads
124A, 124B is longer than the short-pad length W124 of the upper,
lower electrode pads 124A, 124B. However, long-pad length L24 of
the upper, lower electrode pads 24A, 24B is shorter than the
short-pad length W24 of the upper, lower electrode pads 24A, 24B
(L24<W24).
[0122] D) Outer end surfaces 124AS, 124BS have parts formed outside
the outer edge part 122d, and they have parts formed outside than
the upper, lower through holes 123A, 123B. However, outer end
surfaces 24AS, 24BS are entirely disposed inside the outer edge
part 22d, and they are disposed inside the upper, lower through
holes 23A, 23B.
[0123] E) The upper, lower electrode pads 124A, 124B are formed in
size larger than the upper, lower through holes 123A, 123B.
However, the upper, lower electrode pad 24A, 24B are formed in size
smaller than the upper, lower through holes 23A, 23B.
[0124] F) The upper, lower electrode pads 124A, 124B are in contact
with the exposed surface of the upper, lower electrode film 121b,
121c inside the through holes 123A, 123B. However, the upper, lower
electrode pad 24A, 24B are in contact with only a part of the
inside exposed surface 21bb, 21aa.
[0125] As described above, the thin-film piezoelectric material
elements 12b is different in structures of the upper, lower through
holes 23A, 23B, the upper, lower electrode pad 24A, 24B and the
surface layer insulating film 22 respectively.
[0126] By the way, the active length AL is decided by the length of
long-side direction of the part which existing part in the pad
region 25 and OVL in FIG. 6 are removed from the laminated
structure part 121. The OVL is corresponding to the part which the
flexure substrate 4, the laminated structure part 21 and top
disposed part 22a of the surface layer insulating film 22 are
overlaid. There is no great difference between the laminated
structure part 21 and the laminated structure part 121 about length
of part existing in the pad region 25,125 and length of OVL.
However, respective active length AL and ALX are different as
follows.
[0127] In the conventional thin-film piezoelectric material
elements 112b, the upper, lower electrode pad 124A, 124B are
extended from the through holes 123A, 123B to upper side of the
long-side disposed parts 122c through the side disposed parts 122b.
And as illustrated in FIG. 26, part, of the upper, lower electrode
pad 124A, 124B, on the long-side disposed parts 122c (projected
part 124AX, 124BX) are connected to the suspension pad 26.
[0128] On the other hand, in the thin-film piezoelectric material
elements 12b, the upper, lower through holes 23A, 23B, the upper,
lower electrode pads 24A, 24B and the surface layer insulating film
22 are provided, parts connected with the suspension pad 26 are the
upper, lower electrode pads 24A, 24B.
[0129] Then, the upper, lower electrode pads 24A, 24B are disposed
inside the outer edge part 22d, and they are out of contact with
the side disposed parts 22b, they are entirely disposed inside the
top disposed part 22a. Further, as illustrated in FIG. 23 (a), FIG.
23 (b), the length 25X, of the pad region 25 and long-side disposed
parts 22c along the long-side direction of the thin-film
piezoelectric material elements 12b, are greatly shortened as
compared with the length 125X of the pad region 125 and long-side
disposed parts 122c, and lengths along the long-side direction of
the upper, lower electrode pads 24A, 24B are also greatly shortened
as compared with conventional one.
[0130] Therefore, a space along the long-side direction of the
thin-film piezoelectric material elements 12b is larger than a
space along the long-side direction of the thin-film piezoelectric
material elements 112b, thereby the length of the laminated
structure part 21 along the long-side direction can be made longer
than the length of the laminated structure part 121 along the
long-side direction.
[0131] Accordingly, in the thin-film piezoelectric material
elements 12b, the active length is extended than the conventional
thin-film piezoelectric material elements 112b, the active length
AL can be made longer than the active length ALX. Therefore, the
stroke of the thin-film piezoelectric material elements 12b is
increased than the stroke of the thin-film piezoelectric material
elements 112b.
[0132] Further, concerning the upper, lower electrode pad 24A, 24B,
the long-pad lengths L24 of them are shorter than the short-pad
lengths W24. Because this is effective for shortening the space of
the thin-film piezoelectric material elements 12b along the
long-side direction, the space of the thin-film piezoelectric
material elements 12b along the long-side direction is further
extended, thereby the active length is further extended.
[0133] Further, the outer end surfaces 24AS, 24BS of the upper,
lower electrode pads 24A, 24B are entirely flat, and they do not
have bending parts like the upper, lower electrode pads 124A, 124B.
If the bending parts exist like the upper, lower electrode pads
124A, 124B, existence of the parts on the side disposed part 122b
bring difficulty about approach of the thin-film piezoelectric
material elements 112b to the suspension pad 26, thereby space
extension of the thin-film piezoelectric material elements 112b
along the long-side direction is difficult.
[0134] However, in case of the thin-film piezoelectric material
elements 12b, the outer end surfaces 24AS, 24BS are entirely flat,
and upper, lower electrode pads 24A, 24B do not have bending parts.
Therefore, the thin-film piezoelectric material elements 12b is
able to be approached, space extension of the thin-film
piezoelectric material elements 12b along the long-side direction
is able to be executed.
[0135] Further, in case of the thin-film piezoelectric material
elements 12b, long-side length L22c of the long-side disposed parts
22c is shorter than the long-side length L23 of the upper through
hole 23A. Therefore, the thin-film piezoelectric material elements
12b is able to be more approached, the length of the thin-film
piezoelectric material elements 12b is able to be extended. This
brings further space extension of the thin-film piezoelectric
material elements 12b along the long-side direction.
[0136] On the other hand, as illustrated in FIG. 21(a), the
conventional thin-film piezoelectric material elements 190, having
a piezoelectric material film 141, flat flexure substrate 144 and a
base insulating layer 145 has a problem in which the stroke escape
in a bending direction. Therefore, as illustrated in FIG. 21(b),
the thin-film piezoelectric material elements 191, having the base
insulating layer 155 instead of the base insulating layer 145, is
conventionally known. A cavity 156 is formed in the base insulating
layer 155.
[0137] Then, as illustrated in FIG. 22(a), the stroke of the
thin-film piezoelectric material elements 190 is the size that
subtract reduced amount with bending of the piezoelectric material
film 141 from 2.DELTA. (two times of .DELTA.) when the
piezoelectric material film 141 is flat. Further, as illustrated in
FIG. 22(a), the stroke of the thin-film piezoelectric material
elements 191 is the size that subtract reduced amount with bending
of the piezoelectric material film 141 from 2.DELTA.+2h Sin
.theta., when the piezoelectric material film 141 is flat.
[0138] The thin-film piezoelectric material elements 191 has an
effect by improvement of escaping stroke in bending direction, but
length of the piezoelectric material film 141 is the same with the
thin-film piezoelectric material elements 191, so there is no
difference about active length.
[0139] On the other hand, in case of the thin-film piezoelectric
material elements 12b according to the present invention, the
long-side length of the laminated structure part 21 is longer than
the conventional one, so active length become longer than the
conventional one. Accordingly, active length is extended than the
conventional one, the stroke is also increased than the
conventional one.
Modified Example 1
[0140] Subsequently, the thin-film piezoelectric material element
42b according to the modified example 1 will be explained with
reference to FIG. 9 to FIG. 12. Here, FIG. 9 is a plan view,
similar with FIG. 5, showing the thin-film piezoelectric material
element 42b and the peripheral part according to the modified
example 1. FIG. 10 is a sectional view taken along the line 10-10
in FIG. 9, FIG. 11 is a sectional view taken along the line 11-11
in FIG. 9. FIG. 12 is a sectional view, similar with FIG. 10,
showing the thin-film piezoelectric material element 42b, connected
to the suspension pad 26 by the connecting electrode 18b. Note that
the connecting electrode 18b is omitted in FIGS. 9-11 for
convenience of illustration.
[0141] The thin-film piezoelectric material element 42b are
different in that it has upper, lower electrode pads 34A, 34B
instead of upper, lower electrode pads 24A, 24B, as compared with
the thin-film piezoelectric material element 12b.
[0142] The upper electrode pad 34A have an inside pad part 34Aa and
outside pad part 34Ab. The inside pad part 34Aa and outside pad
part 34Ab are unified.
[0143] The inside pad part 34Aa is formed inside the upper through
hole 23A, but a part of the inside pad part 34Aa is in contact with
the upper through hole 23A. The inside pad part 34Aa is formed in
the rectangular parallelepiped shape. The inside pad part 34Aa is
directly in contact with the inside exposed surface 21bb, and
disposed entirely inside the outer edge part 22d. Further, the
inside pad part 34Aa is formed without contact with the side
disposed parts 22b.
[0144] The outside pad part 34Ab is a part which extends outside
than the upper through hole 23A (referred to also extended part).
The outside pad part 34Ab is disposed in the closer position than
the inside pad part 34Aa to the suspension pads 26. The outside pad
part 34Ab is formed on the surface layer insulating film 22. The
outside pad part 34Ab is disposed entirely inside the outer edge
part 22d. The outside pad part 34Ab is formed without contact with
the side disposed parts 22b.
[0145] The upper electrode pad 34A has a long-pad length L34 and
the short-pad length W24, it is preferable that the long-pad length
L34 is less than the short-pad length W24 (L34 W24).
[0146] Further, the upper electrode pad 34A has an outer end
surface 34AS having rectangular shape in a plan view. As
illustrated in FIG. 9, the fine mesh pattern is drawn in the outer
end surface 34AS. As illustrated in FIG. 10, the outer end surface
34AS is a part formed outside the top disposed part 22a. The outer
end surface 34AS is entirely flat. A part of the outer end surface
34AS is disposed outside the upper through hole 23A, but the outer
end surface 34AS is entirely inside the outer edge part 22d.
[0147] As illustrated in FIG. 11, the lower electrode pad 34B have
an upper pad part 34Ba and lower pad part 34Bb. The upper pad part
34Ba is connected to the top surface of the lower pad part
34Bb.
[0148] The upper pad part 34Ba have an inside pad part and outside
pad part, similar with the upper electrode pad 34A, the inside pad
part and outside pad part are unified. The upper pad part 34Ba is
disposed entirely inside the outer edge part 22d, similar with the
upper electrode pad 34A. Further, the upper pad part 34Ba is formed
without contact with the side disposed parts 22b.
[0149] The lower pad part 34Bb penetrates the piezoelectric
material film 21a. The lower pad part 34Bb is in directly contact
with the top surface of the lower electrode film 21c.
[0150] As illustrated in FIG. 12, the thin-film piezoelectric
material elements 42b, having the above-described structure, is
connected to suspension pads 26, 26 with connecting electrode 18b.
In this case, connecting electrodes 18b, 18b connect outer end
surfaces 34AS, 34BS of the upper, lower electrode pads 34A, 34B to
suspension pads 26, 26, respectively.
[0151] The above-described thin-film piezoelectric material
elements 42b has the same the upper, lower through holes 23A, 23B
with the thin-film piezoelectric material elements 12b and further
it has the upper, lower electrode pads 34A, 34B, and the surface
layer insulating film 22.
[0152] Parts of the upper, lower electrode pads 34A, 34B are
extended outside the upper, lower through holes 23A, 23B unlike the
upper, lower electrode pads 24A, 24B, but the upper, lower
electrode pads 34A, 34B are entirely not in contact with the side
disposed parts 22, and the upper, lower electrode pads 34A, 34B are
disposed entirely inside the outer edge part 22d. Therefore, in
case of the thin-film piezoelectric material elements 42b, a space
is also able to be secured along the long-side direction, similar
with the thin-film piezoelectric material elements 12b, length of
the laminated structure part 21 along the long-side direction can
be made longer than a length of the laminated structure part 121
along the long-side direction.
[0153] Therefore, the active length of the thin-film piezoelectric
material elements 42b is also extended than the active length of
the thin-film piezoelectric material elements 112b, the active
length AL is able to be extended than the conventional active
length ALX. Accordingly, the stroke of the thin-film piezoelectric
material elements 42b is increased than the stroke of the thin-film
piezoelectric material elements 112b.
[0154] Further, when the long-pad length L34 of the upper, lower
electrode pads 34A, 34B is shorter than the short-pad length W24,
the space of the thin-film piezoelectric material elements 42b
along the long-side direction is further extended, thereby the
active length is further extended.
[0155] Further, the outer end surfaces 34AS, 34BS of the upper,
lower electrode pads 34A, 34B are flat, and they do not have
bending parts. Therefore, the thin-film piezoelectric material
elements 42b is able to be approached to the suspension pad 26,
further space extension of the thin-film piezoelectric material
elements 42b along the long-side direction is able to be
executed.
Modified Example 2
[0156] Subsequently, the thin-film piezoelectric material element
52b according to the modified example 2 will be explained with
reference to FIG. 13 to FIG. 16. Here, FIG. 13 is a plan view,
similar with FIG. 5, showing the thin-film piezoelectric material
element 52b and the peripheral part according to the modified
example 2. FIG. 14 is a sectional view taken along the line 14-14
in FIG. 13, FIG. 15 is a sectional view taken along the line 15-15
in FIG. 13. FIG. 16 is a sectional view, similar with FIG. 14,
showing the thin-film piezoelectric material element 52b, connected
to the suspension pad 26 by the connecting electrode 18b. Note that
the connecting electrode 18b is omitted in FIGS. 13-15 for
convenience of illustration.
[0157] The thin-film piezoelectric material element 52b are
different in that it does not have upper, lower electrode pads 24A,
24B, as compared with the thin-film piezoelectric material element
12b.
[0158] However, the connecting electrode 18b, 18b are formed
directly on the upper, lower electrode film 21b, 21c. Thereby, as
illustrated in FIG. 16, the thin-film piezoelectric material
element 52b is connected to the suspension pad 26.
[0159] The thin-film piezoelectric material element 52b has the
same surface layer insulating film 22 as the thin-film
piezoelectric material element 12b. Because, the surface layer
insulating film 22 has the long-side disposed parts 22c, the
long-side length L22c is shorter than the long-side length L23, the
thin-film piezoelectric material elements 52b is able to be
approached so as not to be in touch with the suspension pad 26.
[0160] Therefore, the length of the thin-film piezoelectric
material element 52b is able to be extended, the space along the
long-side direction of the thin-film piezoelectric material element
52b is able to be extended, the active length is extended.
Modified Example 3
[0161] Subsequently, the thin-film piezoelectric material element
62b according to the modified example 3 will be explained with
reference to FIG. 17 to FIG. 20. Here, FIG. 17 is a plan view,
similar with FIG. 5, showing the thin-film piezoelectric material
element 62b and the peripheral part according to the modified
example 3. FIG. 18 is a sectional view taken along the line 18-18
in FIG. 17, FIG. 19 is a sectional view taken along the line 19-19
in FIG. 17. FIG. 20 is a sectional view, similar with FIG. 19,
showing the thin-film piezoelectric material element 62b, connected
to the suspension pad 26 by the connecting electrode 18b. Note that
the connecting electrode 18b is omitted in FIGS. 17-19 for
convenience of illustration.
[0162] The thin-film piezoelectric material element 62b are
different in that it has upper, lower electrode pads 44A, 44B
instead of upper, lower electrode pads 24A, 24B, as compared with
the thin-film piezoelectric material element 12b.
[0163] The upper electrode pad 44A have an inside pad part 44Aa and
outside pad part 44Ab. The inside pad part 44Aa and outside pad
part 44Ab are unified.
[0164] The inside pad part 44Aa is formed inside the upper through
hole 23A, further it is in contact with the upper through hole 23A.
The inside pad part 44Aa is formed in the rectangular
parallelepiped shape. The inside pad part 44Aa is directly in
contact with the inside exposed surface 21bb, and disposed entirely
inside the outer edge part 22d. Further, the inside pad part 44Aa
is formed without contact with the side disposed parts 22b.
[0165] The outside pad part 44Ab is a part, like flange, which
extends outside the upper through hole 23A. The outside pad part
44Ab is formed on the surface layer insulating film 22. However,
the outside pad part 44Ab is disposed entirely inside the outer
edge part 22d. The outside pad part 44Ab is formed without contact
with the side disposed parts 22b.
[0166] The upper electrode pad 44A has a long-pad length L44 and a
short-pad length W44, it is preferable that the long-pad length L44
is less than the short-pad length W44 (L44 W44).
[0167] Further, the upper electrode pad 44A has an outer end
surface 44AS having rectangular shape in a plan view. As
illustrated in FIG. 17, the fine mesh pattern is drawn in the outer
end surface 44AS. As illustrated in FIG. 18, the outer end surface
44AS is a part formed outside the top disposed part 22a. The outer
end surface 44AS is entirely flat. A part of the outer end surface
44AS is disposed outside the upper through hole 23A, but the outer
end surface 44AS is entirely inside the outer edge part 22d.
[0168] As illustrated in FIG. 19, the lower electrode pad 44B have
an upper pad part 44Ba and lower pad part 44Bb. The upper pad part
44Ba is connected to the top surface of the lower pad part
44Bb.
[0169] The upper pad part 44Ba have an inside pad part and outside
pad part, similar with the upper electrode pad 44A, the inside pad
part and outside pad part are unified. The upper pad part 44Ba is
disposed entirely inside the outer edge part 22d, similar with the
upper electrode pad 44A. Further, the upper pad part 44Ba is formed
without contact with the side disposed parts 22b.
[0170] The lower pad part 44Bb penetrates the piezoelectric
material film 21a. The lower pad part 44Bb is in directly contact
with the top surface of the lower electrode film 21c.
[0171] As illustrated in FIG. 20, the thin-film piezoelectric
material elements 62b, having the above-described structure, is
connected to suspension pads 26, 26 with connecting electrode 18b.
In this case, connecting electrodes 18b, 18b connect outer end
surfaces 44AS, 44BS of the upper, lower electrode pads 44A, 44B to
suspension pads 26, 26, respectively.
[0172] The above-described thin-film piezoelectric material
elements 62b has the upper, lower through holes 23A, 23B, the
upper, lower electrode pads 44A, 44B, and the surface layer
insulating film 22.
[0173] Parts of the upper, lower electrode pads 44A, 44B are
extended outside the upper, lower through holes 23A, 23B unlike the
upper, lower electrode pads 24A, 24B, but the upper, lower
electrode pads 44A, 44B are entirely not in contact with the side
disposed parts 22, and the upper, lower electrode pads 44A, 44B are
disposed entirely inside the outer edge part 22d. Therefore, in
case of the thin-film piezoelectric material elements 62b, a space
is also able to be secured along the long-side direction, similar
with the thin-film piezoelectric material elements 12b, length of
the laminated structure part 21 along the long-side direction can
be made longer than a length of the laminated structure part 121
along the long-side direction.
[0174] Therefore, the active length of the thin-film piezoelectric
material elements 62b is also extended than the active length of
the thin-film piezoelectric material elements 112b, the active
length AL is able to be extended than the conventional active
length ALX. Accordingly, the stroke of the thin-film piezoelectric
material elements 62b is increased than the stroke of the thin-film
piezoelectric material elements 12b.
[0175] Further, when the long-pad length L44 of the upper, lower
electrode pads 44A, 44B is shorter than the short-pad length W44,
the space of the thin-film piezoelectric material elements 62b
along the long-side direction is further extended, thereby the
active length is further extended.
[0176] Further, the outer end surfaces 44AS, 44BS of the upper,
lower electrode pads 44A, 44B are flat, and they do not have
bending parts. Therefore, the thin-film piezoelectric material
elements 62b is able to be approached, further space extension of
the thin-film piezoelectric material elements 62b along the
long-side direction is able to be executed.
[0177] (Embodiments of Hard Disk Drive)
[0178] Next, embodiments of the hard disk drive will now be
explained with reference to FIG. 27.
[0179] FIG. 27 is a perspective view illustrating a hard disk drive
201 equipped with the above-mentioned HGA 1. The hard disk drive
201 includes a hard disk (magnetic recording medium) 202 rotating
at a high speed and the HGA 1. The hard disk drive 201 is an
apparatus which actuates the HGA 1, so as to record/reproduce data
onto/from recording surfaces of the hard disk 202. The hard disk
202 has a plurality of (4 in the drawing) platters. Each platter
has a recording surface opposing its corresponding the head slider
60.
[0180] The hard disk drive 201 positions the head slider 60 on a
track by an assembly carriage device 203. A thin-film magnetic
head, not illustrated, is formed on this head slider 60. Further,
the hard disk drive 201 has a plurality of drive arms 209. The
drive arms 209 pivot about a pivot bearing shaft 206 by means of a
voice coil motor (VCM) 205, and are stacked in a direction along
the pivot bearing shaft 206. Further, the HGA 1 is attached to the
tip of each drive arm 209.
[0181] Further, the hard disk drive 201 has a control circuit 204
controlling recording/reproducing.
[0182] In the hard disk drive 201, when the HGA 1 is rotated, the
head slider 60 moves in a radial direction of the hard disk 202,
i.e., a direction traversing track lines.
[0183] In case such hard disk drive 201 are formed with the
above-described thin-film piezoelectric material elements 12a, 12b,
because the extension of the active length brings the increase of
the stroke, minute adjustment for position of the thin-film
magnetic head is able to be executed accurately.
[0184] This invention is not limited to the foregoing embodiments
but various changes and modifications of its components may be made
without departing from the scope of the present invention. Besides,
it is clear that various embodiments and modified examples of the
present invention can be carried out on the basis of the foregoing
explanation. Therefore, the present invention can be carried out in
modes other than the above-mentioned best modes within the scope
equivalent to the following claims.
* * * * *