U.S. patent application number 14/951790 was filed with the patent office on 2016-03-17 for wired circuit board and producing method thereof.
This patent application is currently assigned to NITTO DENKO CORPORATION. The applicant listed for this patent is NITTO DENKO CORPORATION. Invention is credited to Jun ISHII, Saori KANAZAKI.
Application Number | 20160081185 14/951790 |
Document ID | / |
Family ID | 49668867 |
Filed Date | 2016-03-17 |
United States Patent
Application |
20160081185 |
Kind Code |
A1 |
ISHII; Jun ; et al. |
March 17, 2016 |
WIRED CIRCUIT BOARD AND PRODUCING METHOD THEREOF
Abstract
A wired circuit board includes a wire, and a terminal formed
continuously to the wire to be electrically connected to an
electronic element at one surface thereof in a thickness direction
of the wired circuit board. The terminal includes, at the one
surface thereof in the thickness direction, a projecting portion
projecting toward one side thereof in the thickness direction, and
a covering layer covering one end portion of the projecting portion
in the thickness direction.
Inventors: |
ISHII; Jun; (Osaka, JP)
; KANAZAKI; Saori; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NITTO DENKO CORPORATION |
Osaka |
|
JP |
|
|
Assignee: |
NITTO DENKO CORPORATION
Osaka
JP
|
Family ID: |
49668867 |
Appl. No.: |
14/951790 |
Filed: |
November 25, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13875896 |
May 2, 2013 |
9253879 |
|
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14951790 |
|
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|
61689744 |
Jun 12, 2012 |
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Current U.S.
Class: |
174/255 |
Current CPC
Class: |
H05K 3/321 20130101;
G11B 5/484 20130101; G11B 5/4873 20130101; H05K 1/189 20130101;
H05K 2201/0373 20130101; G11B 5/4853 20130101; G11B 5/486 20130101;
H05K 3/4007 20130101; H05K 3/06 20130101; H05K 2201/09072 20130101;
H05K 2201/053 20130101; H05K 2201/10083 20130101; H05K 1/0296
20130101 |
International
Class: |
H05K 1/02 20060101
H05K001/02; H05K 1/18 20060101 H05K001/18 |
Foreign Application Data
Date |
Code |
Application Number |
May 30, 2012 |
JP |
2012-122685 |
Claims
1. A wired circuit board, comprising: a wire; and a terminal formed
continuously to the wire to be electrically connected to an
electronic element at one surface thereof in a thickness direction
of the wired circuit board, wherein the terminal includes, at the
one surface thereof in the thickness direction, a projecting
portion projecting toward one side thereof in the thickness
direction, and a covering layer covering one end portion of the
projecting portion in the thickness direction, wherein the wire and
the terminal are provided integrally in a conductive pattern, the
wired circuit board further comprising: an insulating base layer
formed on the one side of the conductive pattern in the thickness
direction; and a metal supporting board formed on the one side of
the insulating base layer in the thickness direction, wherein the
insulating base layer is formed with a base opening exposing the
one surface of the terminal in the thickness direction, wherein the
metal supporting board is formed with a support opening exposing
the one surface of the terminal in the thickness direction, and
wherein the covering layer is formed of the same material as that
of the metal supporting board.
2.-14. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims the benefit of U.S.
Provisional Application No. 61/689,744, filed on Jun. 12, 2012, and
also claims priority from Japanese Patent Application No.
2012-122685 filed on May 30, 2012, the contents of which are herein
incorporated by reference into this application.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a wired circuit board, and
particularly to a wired circuit board used preferably for a
suspension board with circuit mounted in a hard disk drive, and a
producing method thereof.
[0004] 2. Description of the Related Art
[0005] A suspension board with circuit includes a metal supporting
board, an insulating base layer formed thereon, and a conductive
layer formed thereon and having head-side terminals to be connected
to a magnetic head. On the suspension board with circuit, the
magnetic head is mounted and connected to the head-side terminals,
and the suspension board with circuit is mounted in a hard disk
drive with the metal supporting board being supported on a load
beam.
[0006] In recent years, it has been examined to connect such a
suspension board with circuit to various electronic elements such
as, e.g., a piezoelectric element (piezo-element) and accurately
and finely adjust the position and angle of a magnetic head, and so
forth. Because of its relatively low heat resistance, such an
electronic element needs to be electrically connected to
electronic-element-side terminals (terminals different from
head-side terminals and formed with a conductive layer) at a
relatively low temperature via a conductive adhesive or the
like.
[0007] The low-temperature connection between the electronic
element having low heat resistance and the electronic-element-side
terminals via the conductive adhesive is lower in the strength of
connection (adhesive force) between the conductive adhesive and the
electronic-element-side terminals than high-temperature connection
therebetween via a molten solder. Accordingly, it is required to
sufficiently improve the connection strength.
[0008] In view of this, it has been proposed that, in the
conductive layer of a wired circuit board, circular lands are
provided with grooves (through grooves) formed along the
circumferential directions of the lands to extend therethrough in
the thickness direction thereof (see, e.g., Japanese Unexamined
Patent Publication No. 2010-251619). In the wired circuit board
described in Japanese Unexamined Patent Publication No.
2010-251619, a conductive paste is in contact with the upper
surfaces of the lands and also filling the grooves. Since the upper
surfaces of the lands and the inner side surfaces of the grooves
are in contact with the conductive paste, the lands increase the
contact area with the conductive paste to improve the adhesive
force.
SUMMARY OF THE INVENTION
[0009] However, in the wired circuit board in Japanese Unexamined
Patent Publication No. 2010-251619, the upper surfaces of the lands
and the inner side surfaces of the grooves are in mere contact with
the conductive paste, which has a limit to an increase in the
contact area between the lands and the conductive paste.
[0010] On the other hand, a method is also attempted which performs
roughening treatment on the surfaces of the electronic-element-side
terminals to improve the adhesive force between the conductive
adhesive and the electronic-element-side terminals based on an
anchor effect. However, in such a method, it is necessary to
provide an extra step of performing the roughening treatment on the
electronic-element-side terminals. This leads to the problems of
extra labor and trouble and increased production cost.
[0011] It is therefore an object of the present invention to
provide a wired circuit board which allows an improvement in the
reliability of the connection between an electronic element and a
terminal and a method of producing the wired circuit board which
allows the wired circuit board to be produced easily at low
cost.
[0012] A wired circuit board of the present invention includes a
wire, and a terminal formed continuously to the wire to be
electrically connected to an electronic element at one surface
thereof in a thickness direction of the wired circuit board. The
terminal includes, at the one surface thereof in the thickness
direction, a projecting portion projecting toward one side thereof
in the thickness direction, and a covering layer covering one end
portion of the projecting portion in the thickness direction.
[0013] In such a configuration, the terminal is formed with the
projecting portion projecting toward the one side thereof in the
thickness direction, and the covering layer covering the one end
portion of the projecting portion in the thickness direction.
[0014] Since the terminal has the projecting portion formed at the
one surface thereof in the thickness direction and the covering
layer formed at the one end portion of the projecting portion in
the thickness direction, compared to the case where the one surface
of the terminal in the thickness direction is formed flat, the area
of the terminal to be connected to the electronic element can be
increased accordingly.
[0015] In particular, on the one surface of the terminal in the
thickness direction, there are formed not only the projecting
portion, but also the covering layer formed at the one end portion
of the projecting portion in the thickness direction. Accordingly,
compared to the case where only the projecting portion is formed,
the area of the terminal to be connected to the electronic element
can be further increased.
[0016] As a result, it is possible to improve the reliability of
the connection between the electronic element and the terminal.
[0017] In the wired circuit board of the present invention, it is
preferable that the terminal is to be used for being connected to
the electronic element via a conductive adhesive.
[0018] In such a configuration, the area of the terminal to be
connected to the electronic element is sufficiently provided.
Accordingly, it is possible to improve the adhesive force between
the conductive adhesive and the terminal.
[0019] Therefore, it is possible to reliably connect the terminal
and the electronic element using the conductive adhesive.
[0020] It is also preferable that, in the wired circuit board of
the present invention, the wire and the terminal are provided
integrally in a conductive pattern, the wired circuit board further
includes an insulating base layer formed on the one side of the
conductive pattern in the thickness direction, and the insulating
base layer is formed with a base opening exposing the one surface
of the terminal in the thickness direction.
[0021] In such a configuration, it is possible to expose the one
surface of the terminal in the thickness direction defined by the
base opening of the insulating base layer.
[0022] This allows the insulating base layer to suppress a short
circuit between the portion of the conductive pattern other than
the terminal and another member, and also allows the terminal
exposed from the base opening to be connected to the electronic
element.
[0023] In the wired circuit board of the present invention, it is
also preferable that the covering layer includes a first covering
layer formed of the same material as that of the insulating base
layer.
[0024] In such a configuration, the insulating base layer and the
first covering layer are formed of the same material.
[0025] Therefore, it is possible to bring the first covering layer
into close contact with the projecting portion using the adhesive
force between the insulating base layer and the conductive
pattern.
[0026] When a conductive adhesive is used, it is also possible to
improve adhesion to the conductive adhesive.
[0027] Moreover, since the insulating base layer and the first
covering layer are formed of the same material, the insulating base
layer and the first covering layer can be formed
simultaneously.
[0028] This allows a reduction in the number of production steps
and a reduction in cost.
[0029] In the wired circuit board of the present invention, it is
also preferable that a total sum of a thickness of the projecting
portion of the terminal and a thickness of the first covering layer
thereof is the same as or larger than a thickness of the insulating
base layer.
[0030] Such a configuration allows a further increase in the area
of the terminal to be connected to the electronic element.
[0031] Therefore, it is possible to further improve the reliability
of the connection between the electronic element and the
terminal.
[0032] It is also preferable that the wired circuit board of the
present invention further includes a metal supporting board formed
on the one side of the insulating base layer in the thickness
direction, and the metal supporting board is formed with a support
opening exposing the one surface of the terminal in the thickness
direction.
[0033] In such a configuration, it is possible to expose the one
surface of the terminal in the thickness direction defined by the
support opening of the metal supporting board.
[0034] Therefore, it is possible to reinforce the terminal from the
one side in the thickness direction with the metal supporting board
to be able to ensure the rigidity of the terminal, and also connect
the terminal exposed from the support opening to the electronic
element.
[0035] In the wired circuit board of the present invention, it is
also preferable that the covering layer includes a second covering
layer formed of the same material as that of the metal supporting
board on one end portion of the first covering layer in the
thickness direction.
[0036] In such a configuration, the first covering layer is formed
on the one end portion of the projecting portion in the thickness
direction, and the second covering layer is further formed on the
one end portion of the first covering layer in the thickness
direction.
[0037] Consequently, on the one surface of the terminal in the
thickness direction, there are formed not only the projecting
portion and the first covering layer formed on the one end portion
of the projecting portion in the thickness direction, but also the
second covering layer formed on the one end portion of the first
covering layer in the thickness direction. This allows a further
increase in the area of the terminal to be connected to the
electronic element.
[0038] As a result, it is possible to further improve the
reliability of the connection between the electronic element and
the terminal.
[0039] In addition, it is possible to bring the second covering
layer into close contact with the first covering layer using the
adhesive force between the metal supporting board and the
insulating base layer.
[0040] Moreover, since the metal supporting board and the second
covering layer are formed of the same material, the metal
supporting board and the second covering layer can be formed
simultaneously.
[0041] This allows a reduction in the number of production steps
and a reduction in cost.
[0042] In the wired circuit board of the present invention, it is
also preferable that the covering layer is formed of the same
material as that of the metal supporting board.
[0043] In such a configuration, the covering layer covering the one
end portion of the projecting portion in the thickness direction is
formed of the same material as that of the metal supporting board.
This allows the covering layer to be electrically connected to the
electronic element.
[0044] As a result, compared to the case where the covering layer
is formed of an insulating material, the area of the terminal to be
connected to the electronic element can be increased.
[0045] It is also preferable that the wired circuit board of the
present invention further includes an insulating cover layer formed
on the other side of the conductive pattern in the thickness
direction, and the insulating cover layer is formed with a cover
opening exposing the other surface of the terminal in the thickness
direction.
[0046] In such a configuration, it is possible to expose the other
surface of the terminal in the thickness direction defined by the
cover opening of the cover insulating layer.
[0047] This allows the insulating cover layer to suppress a short
circuit between the portion of the conductive pattern other than
the terminal and another member, and also allows the other surface
of the terminal in the thickness direction to be exposed from the
cover opening. Therefore, the other surface of the terminal in the
thickness direction can also be used for electrical connection.
[0048] A method of producing a wired circuit board of the present
invention includes preparing a metal supporting board, laminating a
covering layer over the metal supporting board, laminating a
conductive layer over the metal supporting board so as to cover the
covering layer, etching the metal supporting board to form a
support opening so as to expose lower surfaces of the conductive
layer and the covering layer therefrom, and etching the conductive
layer exposed from the support opening using the covering layer as
an etching resist to form a terminal including a projecting portion
projecting downward from the lower surface of the conductive layer,
and the covering layer covering a lower end portion of the
projecting portion.
[0049] According to such a producing method of a wired circuit
board, first, over the metal supporting board, the covering layer
is laminated and, over the metal supporting board, the conductive
layer is laminated so as to cover the covering layer. Then, the
foregoing metal supporting board is etched to expose the lower
surfaces of the conductive layer and the covering layer.
Subsequently, using the covering layer as an etching resist, the
conductive layer is etched. In this manner, it is possible to form
the terminal including the projecting portion projecting downward
from the lower surface thereof, and the covering layer covering the
lower end portion of the projecting portion.
[0050] Thus, the conductive layer can be etched using the covering
layer as the etching resist. Accordingly, the covering layer and
the projecting portion can be formed more efficiently than in the
case of forming the covering layer after forming the projecting
portion.
[0051] As a result, it is possible to easily obtain the wired
circuit board which is excellent in the reliability of the
connection with the electronic element at low cost.
[0052] It is preferable that the method of producing a wired
circuit board of the present invention further includes laminating
the covering layer over the metal supporting board and
simultaneously laminating an insulating base layer formed of the
same material as that of the covering layer so as to form a base
opening surrounding the covering layer.
[0053] According to such a method of producing a wired circuit
board, the insulating base layer and the covering layer which are
formed of the same material can be formed simultaneously.
[0054] This allows the insulating base layer and the covering layer
to be efficiently formed, and allows the production process to be
simplified.
[0055] Alternatively, the method of producing a wired circuit board
of the present invention includes preparing a metal supporting
board, laminating a first covering layer over the metal supporting
board, laminating a conductive layer over the metal supporting
board so as to cover the first covering layer, etching the metal
supporting board to form a support opening and a second covering
layer so as to expose a lower surface of the conductive layer
therefrom, and etching the conductive layer exposed from the
support opening using the second covering layer as an etching
resist to form a terminal including a projecting portion projecting
downward from the lower surface of the conductive layer, the first
covering layer covering a lower end portion of the projecting
portion, and the second covering layer covering a lower end portion
of the first covering layer.
[0056] According to such a producing method of a wired circuit
board, first, over the metal supporting board, the first covering
layer is laminated and, over the metal supporting board, the
conductive layer is laminated so as to cover the first covering
layer. Then, the foregoing metal supporting board is etched to form
the support opening and the second covering layer to expose the
lower surface of the conductive layer. Subsequently, using the
second covering layer as an etching resist, the conductive layer is
etched. In this manner, it is possible to form the terminal
including the projecting portion projecting downward from the lower
surface thereof, the first covering layer covering the lower end
portion of the projecting portion, and the second covering layer
covering the lower end portion of the first covering layer.
[0057] Thus, the conductive layer can be etched using the second
covering layer as the etching resist. Accordingly, the first
covering layer, the second covering layer, and the projecting
portion can be formed more efficiently than in the case of forming
the first covering layer and the second covering layer after
forming the projecting portion.
[0058] Consequently, on the one surface of the terminal in the
thickness direction, there can be formed not only the projecting
portion and the first covering layer formed on the one end portion
of the projecting portion in the thickness direction, but also the
second covering layer formed on the one end portion of the first
covering layer in the thickness direction. This allows a further
increase in the area of the terminal to be connected to the
electronic element.
[0059] Therefore, it is possible to easily obtain the wired circuit
board which is excellent in the reliability of the connection with
the electronic element at low cost.
[0060] Alternatively, the method of producing a wired circuit board
includes preparing a metal supporting board, laminating a
conductive layer over the metal supporting board, etching the metal
supporting board to form a support opening and a covering layer so
as to expose a lower surface of the conductive layer therefrom, and
etching the conductive layer exposed from the support opening using
the covering layer as an etching resist to form a terminal
including a projecting portion projecting downward from the lower
surface of the conductive layer, and the covering layer covering a
lower end portion of the projecting portion.
[0061] According to such a producing method of a wired circuit
board, first, over the metal supporting board, the conductive layer
is laminated. Then, the metal supporting board is etched to form
the support opening and the covering layer to expose the lower
surface of the conductive layer. Subsequently, using the covering
layer as an etching resist, the conductive layer is etched. In this
manner, it is possible to form the terminal including the
projecting portion projecting downward from the lower surface
thereof, and the covering layer covering the lower end portion of
the projecting portion.
[0062] Thus, the conductive layer can be etched using the covering
layer as the etching resist. Accordingly, the covering layer and
the projecting portion can be formed more efficiently than in the
case of forming the covering layer after forming the projecting
portion.
[0063] As a result, the one end portion of the projecting portion
in the thickness direction can be covered with the covering layer
formed of the same material as that of the metal supporting board.
This allows the covering layer to be electrically connected to the
electronic element.
[0064] Therefore, it is possible to easily obtain the wired circuit
board which is excellent in the reliability of the connection with
the electronic element at low cost.
[0065] With the wired circuit board of the present invention and
the producing method thereof, it is possible to sufficiently
improve the reliability of the connection between the electronic
element and the terminal and also easily produce the wired circuit
board at low cost.
BRIEF DESCRIPTION OF THE DRAWINGS
[0066] FIG. 1 shows a plan view of an assembly including a
suspension board with circuit as an embodiment of the wired circuit
board of the present invention;
[0067] FIG. 2 shows a cross-sectional view of the assembly shown in
FIG. 1 along the line A-A;
[0068] FIG. 3 shows a cross-sectional view of the assembly shown in
FIG. 1 along the line B-B,
[0069] FIG. 3(a) showing a state in which a conductive adhesive is
interposed between a piezoelectric-side terminal and a
piezoelectric element, and
[0070] FIG. 3(b) showing a state in which the piezoelectric-side
terminal and the piezoelectric element are electrically connected
and an outer contact portion and a piezoelectric terminal are
connected via the conductive adhesive;
[0071] FIG. 4 shows an enlarged cross-sectional view of the
piezoelectric-side terminal of the assembly shown in FIG. 3;
[0072] FIG. 5 shows a cross-sectional view of the assembly shown in
FIG. 1 along the line C-C;
[0073] FIG. 6 shows an enlarged plan view of the connecting arm of
the assembly shown in FIG. 1;
[0074] FIG. 7 shows an enlarged bottom view of the connecting arm
of the assembly shown in FIG. 1;
[0075] FIG. 8 is a process view illustrating a producing method of
the suspension board with circuit,
[0076] FIG. 8(a) showing the step of preparing a metal supporting
board,
[0077] FIG. 8(b) showing the step of forming an insulating base
layer, and
[0078] FIG. 8(c) showing the step of forming a conductive
layer;
[0079] FIG. 9 is a process view illustrating the producing method
of the suspension board with circuit, subsequently to FIG. 8,
[0080] FIG. 9(d) showing the step of removing the metal supporting
board and forming a support opening,
[0081] FIG. 9(e) showing the step of removing the
piezoelectric-side terminal and forming projecting portions,
and
[0082] FIG. 9(f) showing the step of forming protective thin
films;
[0083] FIG. 10 shows a cross-sectional view of a pad portion of a
suspension board with circuit as another embodiment of the wired
circuit board of the present invention (a form in which support
covering layers are formed under covering base layers); and
[0084] FIG. 11 shows a cross-sectional view of a pad portion of a
suspension board with circuit as still another embodiment of the
wired circuit board of the present invention (a form in which
support covering layers are formed under projecting portions).
DETAILED DESCRIPTION OF THE INVENTION
[0085] FIG. 1 shows a plan view of an assembly including a
suspension board with circuit as an embodiment of the wired circuit
board of the present invention. FIG. 2 shows a cross-sectional view
of the assembly shown in FIG. 1 along the line A-A. FIG. 3 shows a
cross-sectional view of the assembly shown in FIG. 1 along the line
B-B. FIG. 4 shows an enlarged cross-sectional view of the
piezoelectric-side terminal of the assembly shown in FIG. 3. FIG. 5
shows a cross-sectional view of the assembly shown in FIG. 1 along
the line C-C. FIG. 6 shows an enlarged plan view of the connecting
arm of the assembly shown in FIG. 1. FIG. 7 shows an enlarged
bottom view of the connecting arm of the assembly shown in FIG. 1.
FIGS. 8 and 9 are process views each illustrating a producing
method of the suspension board with circuit.
[0086] Note that, in FIG. 1, an insulating base layer 28 and an
insulating cover layer 29 are omitted for clear illustration of
relative positioning of a metal supporting board 18 and a
conductive pattern 19.
[0087] In FIGS. 1 and 2, an assembly 1 is a head-stack assembly
(HSA) to be mounted in a hard disk drive (not shown). In the
assembly 1, a suspension board with circuit 3 as an example of the
wired circuit board on which a slider 22 mounting a magnetic head
(not shown) is mounted is supported on a support plate 2. The
assembly 1 includes the support plate 2, the suspension board with
circuit 3 disposed on the support plate 2 (on the other side
thereof in the thickness direction, which similarly applies to the
following) and supported on the support plate 2, and piezoelectric
elements (piezo-elements) 5 as an example of electronic elements
for accurately and finely adjusting the position and angle of the
suspension board with circuit 3, while being supported on the
support plate 2.
[0088] The support plate 2 is formed so as to extend in a
longitudinal direction (front-rear direction), and includes an
actuator plate portion 6, a base plate portion 7 formed under the
actuator plate portion 6 (on one side thereof in the thickness
direction, which similarly applies to the following), and a load
beam portion 8 formed to be continued to the front side of the
actuator plate portion 6.
[0089] The actuator plate portion 6 integrally includes a rear
plate portion 9, a front plate portion 10 disposed on the front
side of the rear plate portion 9 to be spaced apart therefrom, and
flexible portions 11 formed between the rear plate portion 9 and
the front plate portion 10.
[0090] The rear plate portion 9 is formed in a generally
rectangular shape (generally projecting shape) in plan view in the
rear end portion of the actuator plate portion 6.
[0091] The front plate portion 10 is formed in a generally
rectangular shape in plan view extending in a widthwise direction
(direction perpendicular to the front-rear direction).
[0092] The flexible portions 11 are provided on both widthwise
sides of the actuator plate portion 6. Each of the flexible
portions 11 is formed to extend between the front end portion of
the rear plate portion 9 and the rear end portion of the front
plate portion 10.
[0093] The both flexible portions 11 have respective middle
portions thereof in the front-rear direction which are formed to be
curved outwardly on both widthwise sides and have generally equal
widths throughout the front-rear direction. Specifically, the
middle portions of the flexible portions 11 in the front-rear
direction are formed so as to outwardly protrude into generally
U-shapes (or generally V-shapes) on both widthwise sides.
[0094] Accordingly, the flexible portions 11 can warp in the
front-rear direction and are formed to be able to bring the front
plate portion 10 away from and closer to the rear plate portion 9
due to the extension/contraction of the piezoelectric elements 5,
as described later.
[0095] The actuator plate portion 6 is also formed with a plate
opening 12 defined by the front surface of the rear plate portion
9, the rear surface of the front plate portion 10, and the
widthwise inner surfaces of the flexible portions 11. The plate
opening 12 extends through the actuator plate portion 6 in the
thickness direction thereof.
[0096] In the front end portion of the rear plate portion 9 and the
rear end portion of the front plate portion 10, two pairs of
attachment regions 13 to which the rear end portions and front end
portions of the piezoelectric elements 5 are respectively attached
are defined. The attachment regions 13 are each defined in a
widthwise elongated generally rectangular shape in bottom view in
one widthwise end portion and the other widthwise end portion of
each of the front end portion of the rear plate portion 9 and the
rear end portion of the front plate portion 10 located to face the
front end portion in the front-rear direction.
[0097] The base plate portion 7 is fixed to the middle portion of
the lower surface of the rear plate portion 9 in each of the
widthwise direction and the front-rear direction. The base plate
portion 7 has a front portion thereof formed in a generally
rectangular shape and a rear portion thereof formed in a generally
semi-circular shape when viewed in plan view.
[0098] The support plate 2 is formed with a hole 14 having a
generally circular shape in bottom view and extending through the
middle portion of the rear plate portion 9 and the middle portion
of the base plate portion 7.
[0099] Note that, to the base plate portion 7, a drive coil (not
shown) for causing the front end portion of the assembly 1 to swing
around the hole 14 is attached.
[0100] The load beam portion 8 is integrally formed with the
actuator plate portion 6. Specifically, the load beam portion 8 is
formed to extend from the front end of the front plate portion 10
toward the front side, and formed in a generally trapezoidal shape
which gradually decreases in width with approach to the frontmost
portion when viewed in plan view.
[0101] The support plate 2 is formed of a metal material such as,
e.g., stainless steel, aluminum, iron, or an alloy thereof.
[0102] The size of the support plate 2 is set appropriately. For
example, the thickness of each of the actuator plate portion 6 and
the load beam portion 8 is in a range of, e.g., 30 to 150 .mu.m,
and the thickness of the base plate portion 7 is in a range of,
e.g., 150 to 200 .mu.m.
[0103] Note that the support plate 2 is provided as an integrated
actuator-plate/load-beam plate integrally including the actuator
plate portion 6 and the load beam portion 8.
[0104] The suspension board with circuit 3 is formed in a generally
flat-belt shape in plan view extending in the front-rear
direction.
[0105] As shown in FIG. 1, the suspension board with circuit 3
includes the metal supporting board 18 and the conductive layer 19
supported on the metal supporting board 18.
[0106] The metal supporting board 18 is formed so as to correspond
to the outer shape of the suspension board with circuit 3, and
integrally includes a wiring portion 16, a front portion 15 formed
on the front side of the wiring portion 16, and a rear portion 17
formed on the rear side of the wiring portion 16.
[0107] The wiring portion 16 integrally includes a linear portion
20 formed in the middle portion of the metal supporting board 18 in
the front-rear direction and extending in the front-rear direction,
and a bent portion 21 bent to one side in the widthwise direction
from the rear end portion of the linear portion 20, and then
further bent rearward. Note that the linear portion 20 and the bent
portion 21 are formed to have generally equal widths throughout the
front-rear direction.
[0108] The front portion 15 is formed in a generally rectangular
shape in plan view continued from the front end of the linear
portion 20 and gradually protruding outward on both widthwise sides
from the wiring portion 16. Specifically, the front portion 15
includes a gimbal 23 on which the slider 22 (described later) is
mounted, and a gimbal rear portion 24 connecting the gimbal 23 and
the linear portion 20.
[0109] The gimbal 23 is formed in a generally rectangular shape in
plan view having a width larger than the width of the linear
portion 20. The gimbal 23 supports front-side terminals 26
(described later), and the slider 22 (described later) having the
magnetic head (not shown) electrically connected to the front-side
terminals 26 (described later) is mounted on the gimbal 23.
[0110] The gimbal rear portion 24 is formed in a generally
triangular shape continued to the rear end of the gimbal 23 and
gradually decreasing in width with approach to the rearmost
portion. To the rear end of the gimbal rear portion 24, the front
end of the linear portion 20 is continued.
[0111] The rear portion 17 is formed in a generally rectangular
shape in plan view continued from the rear end of the bent portion
21 and having generally the same width as that of the bent portion
21.
[0112] The conductive pattern 19 integrally includes wires 25
extending along the front-rear direction, the front-side terminals
26 continued to the front end portions of the wires 25, and
rear-side terminals 27 continued to the rear end portions of the
wires 25 at the upper surface of the metal supporting board 18.
[0113] The wires 25 include signal wires 25A each for transmitting
an electric signal between the magnetic head (not shown) and a
read/write board (not shown), and disposed along the rear portion
17, the bent portion 21, the linear portion 20, the gimbal rear
portion 24, and the gimbal 23 throughout the front-rear direction
of the suspension board with circuit 3. The plurality of (four)
signal wires 25A are arranged in widthwise spaced-apart
relation.
[0114] The wires 25 also include a plurality of (two) power-source
wires 25B.
[0115] The power-source wires 25B are electrically connected to
power-source-side terminals 27B described next. The power-source
wires 25B are disposed to be continued to the power-source-side
terminals 27B in the rear portion 17, arranged in parallel and
spaced-apart relation on both sides of the signal wires 25A in the
rear portion 17, the bent portion 21, and the linear portion 20,
and curved outwardly on both widthwise sides in the middle portion
of the linear portion 20 in the front-rear direction to reach frame
conductors 39 (see FIG. 6) described later.
[0116] The front-side terminals 26 are disposed on the front
portion 15. Specifically, the plurality of (four) front-side
terminals 26 are arranged along the front end surface of the slider
22 in widthwise spaced-apart relation on the front side of the
gimbal 23.
[0117] The front-side terminals 26 are head-side terminals 26A
electrically connected to the magnetic head (not shown).
[0118] The rear-side terminals 27 are disposed on the rear end
portion of the rear portion 17. Specifically, the plurality of
(six) rear-side terminals 27 are arranged to be spaced apart from
each other in the front-rear direction. The rear-side terminals 27
include a plurality of (four) external terminals 27A continued to
the signal wires 25A, and connected to the terminals of the
read/write board.
[0119] The rear-side terminals 27 also include the plurality of
(two) power-source-side terminals 27B continued to the power-source
wires 25B and electrically connected to the piezoelectric elements
5. Note that the power-source-side terminals 27B are disposed in
spaced-apart relation on both sides of the external terminals 27A
in the front-rear direction, and electrically connected to a power
source (not shown).
[0120] As shown in FIGS. 3 and 5, the suspension board with circuit
3 includes the metal supporting board 18, an insulating layer 30
formed on the upper surface thereof, and the conductive pattern 19
covered with the insulating layer 30.
[0121] The metal supporting board 18 is formed of a metal material
such as, e.g., stainless steel, a 42-alloy, aluminum, a
copper-beryllium alloy, or phosphor bronze. Preferably, the metal
supporting board 18 is formed of stainless steel. The thickness of
the metal supporting board 18 is in a range of, e.g., 15 to 50
.mu.m, or preferably 15 to 20 .mu.m.
[0122] The insulating layer 30 includes the insulating base layer
28 formed on the upper surface of the metal supporting board 18,
and the insulating cover layer 29 formed over the insulating base
layer 28 so as to cover the wires 25.
[0123] As shown in FIG. 1, the insulating base layer 28 is formed
in a pattern corresponding to the conductive pattern 19 on the
upper surface of the metal supporting board 18 in the front portion
15, the wiring portion 16, and the rear portion 17.
[0124] The insulating base layer 28 is formed of an insulating
material such as a synthetic resin such as, e.g., a polyimide
resin, a polyamide imide resin, an acrylic resin, a polyether
nitrile resin, a polyether sulfone resin, a polyethylene
terephthalate resin, a polyethylene naphthalate resin, or a
polyvinyl chloride resin. Preferably, the insulating base layer 28
is formed of a polyimide resin.
[0125] The thickness (maximum thickness) of the insulating base
layer 28 is in a range of, e.g., 1 to 35 .mu.m, or preferably 8 to
15 .mu.m.
[0126] The insulating cover layer 29 is formed over the wiring
portion 16, the front portion 15, and the rear portion 17 so as to
cover the upper surfaces of the insulating base layer 28 exposed
from the wires 25 and the upper surface and side surfaces of the
wires 25. The insulating cover layer 29 is also formed in a pattern
exposing the front-side terminals 26 in the front portion 15 and
exposing the rear-side terminals 27 in the rear portion 17, though
not shown.
[0127] The insulating cover layer 29 is formed of the same
insulating material as the insulating material of the insulating
base layer 28. The thickness of the insulating cover layer 29 is in
a range of, e.g., 1 to 40 .mu.m, or preferably 1 to 10 .mu.m.
[0128] As shown in FIGS. 1 and 3, the conductive pattern 19 is
formed in the foregoing pattern over the upper surface of the
insulating base layer 28 in the front portion 15, the wiring
portion 16, and the rear portion 17.
[0129] The conductive layer 19 is formed of a conductive material
such as metal such as, e.g., copper, nickel, gold, or a solder or
an alloy thereof. Preferably, the conductive layer 19 is formed of
copper.
[0130] The thickness of the conductive pattern 19 is in a range of,
e.g., 3 to 15 .mu.m, or preferably 5 to 10 .mu.m.
[0131] The width of each of the wires 25 is in a range of, e.g., 5
to 200 .mu.m, or preferably 8 to 100 .mu.m. The spacing between the
individual wires 25 is in a range of, e.g., 5 to 1000 .mu.m, or
preferably 8 to 100 .mu.m.
[0132] The widths and lengths of the front-side terminals 26 and
the rear-side terminals 27 are in a range of, e.g., 20 to 1000
.mu.m, or preferably 30 to 800 .mu.m. The spacing between the
individual front-side terminals 26 and the spacing between the
individual rear-side terminals 27 are in a range of, e.g., 20 to
1000 .mu.m, or preferably 30 to 800 .mu.m.
[0133] In the suspension board with circuit 3, as shown in FIGS. 1
and 2, the lower surface of the metal supporting board 18 is
supported on the support plate 2. Specifically, the lower surfaces
of the wiring portion 16 and the front portion 15 are supported on
the support plate 2, while the lower surface of the rear portion 17
protrudes rearward from the support plate 2 without being supported
on the support plate 2.
[0134] Specifically, in the suspension board with circuit 3, the
bent portion 21 is disposed in a generally L-shape along the one
widthwise end portion of the rear plate portion 9 and the front end
portion thereof, and the linear portion 20 is disposed to extend
from the widthwise middle portion of the front end portion of the
rear plate portion 9, traverse the widthwise middle portion of the
plate opening 12, and then reach the widthwise middle portion of
the front plate portion 10. Also, in the suspension board with
circuit 3, the front portion 15 is disposed to be formed on the
widthwise middle portion of the load beam portion 8 to extend
throughout the front-rear direction of the load beam portion 8.
[0135] The piezoelectric elements 5 are attached to the lower side
of the support plate 2.
[0136] Specifically, the plurality of (two) piezoelectric elements
5 are provided in widthwise spaced-apart relation.
[0137] Each of the piezoelectric elements 5 is an actuator
extendable/contractable in the front-rear direction, and is formed
in a generally rectangular shape in plan view elongated in the
front-rear direction. Each of the piezoelectric elements 5 is
disposed so as to span the plate opening 12 in the front-rear
direction.
[0138] Specifically, the both end portions of each of the
piezoelectric elements 5 in the front-rear direction are bonded to
the respective attachment regions 13 (broken lines of FIG. 1) in
the front end portion of the rear plate portion 9 and in the rear
end portion of the front plate portion 10 via adhesive layers 31,
and fixed thereto.
[0139] As shown in FIG. 3, in the middle portion of the upper
surface of each of the piezoelectric elements 5 in the front-rear
direction, a piezoelectric terminal 48 is provided, and
electrically connected to a piezoelectric-side terminal 40
(described later) of the suspension board with circuit 3 via a
conductive adhesive 46.
[0140] Each of the piezoelectric elements 5 is supplied with
electricity from the piezoelectric-side terminal 40 and the
piezoelectric terminal 48, and the voltage thereof is controlled to
extend/contract the piezoelectric element 5.
[0141] Next, a detailed description is given to the
piezoelectric-side terminal 40 on one widthwise side in the
suspension board with circuit 3. The piezoelectric-side terminal 40
and the wires 25 are integrally included in the conductive pattern
19. Note that the piezoelectric-side terminal 40 on the other
widthwise side is formed to be symmetrical with the
piezoelectric-side terminal 40 on the one widthwise side with
respect to the linear portion 20, and a description thereof is
omitted.
[0142] In the suspension board with circuit 3, as shown in FIG. 6,
connecting arms 32 each including the piezoelectric-side terminal
40 are provided.
[0143] Each of the connecting arms 32 is provided so as to protrude
widthwise outward in an arm-like shape from the middle portion of
the linear portion 20 in the front-rear direction thereof.
[0144] The connecting arm 32 includes a pad portion 33 disposed on
one widthwise side of the linear portion 20 to be spaced apart
therefrom, and a joint portion 41 coupling the pad portion 33 to
the linear portion 20.
[0145] As shown in FIG. 4, each of the pad portions 33 includes the
insulating base layer 28, the conductive pattern 19 formed on the
upper surface of the insulating base layer 28, and the insulating
cover layer 29 formed on the upper surface of the insulating base
layer 28 and around the conductive pattern 19.
[0146] In the pad portion 33, as shown in FIGS. 6 and 7, the metal
supporting board 18 is formed as a support pad 34 having a
generally annular (ring) shape in plan view. That is, as shown in
FIG. 3, the middle portion of the support pad 34 is formed with a
support opening 35 having a generally circular shape in plan view
and extending therethrough in the thickness direction.
[0147] In the pad portion 33, as shown in FIGS. 4 and 6, the
insulating base layer 28 is formed in a generally annular (ring)
shape in plan view slightly smaller than the support pad 34. The
middle portion of the insulating base layer 28 is formed with a
base opening 37 having a generally circular shape in plan view and
extending therethrough in the thickness direction. The insulating
base layer 28 is formed such that the diameter of the base opening
37 thereof has the same diameter as the inner diameter of the
support pad 34 (diameter of the support opening 35) and the outer
diameter thereof is smaller than the outer diameter of the support
pad 34.
[0148] That is, as shown in FIG. 4, the insulating base layer 28 is
formed to overlap the support pad 34 when projected in the
thickness direction. In other words, the insulating base layer 28
is laminated on the upper surface of the support pad 34.
[0149] As shown in FIGS. 4 and 6, the conductive pattern 19
integrally includes the frame conductor 39 formed on the upper
surface of the insulating base layer 28, and the piezoelectric-side
terminal 40 as an example of a terminal continued to the inside of
the frame conductor 39.
[0150] As shown in FIG. 6, the frame conductor 39 is formed in a
generally annular (ring) shape in plan view smaller than the
insulating base layer 28. Specifically, as shown in FIG. 4, the
frame conductor 39 is formed such that the outer diameter thereof
is smaller than the outer diameter of the insulating base layer 28
and the inner diameter thereof is generally the same as the inner
diameter of the insulating base layer 28 (diameter of the base
opening 37) when projected in the thickness direction. That is, the
frame conductor 39 is laminated on the upper surface of the inner
peripheral portion of the insulating base layer 28.
[0151] As shown in FIG. 6, the piezoelectric-side terminal 40 is
formed in a generally circular shape in plan view continued to the
inner peripheral portion of the frame conductor 39.
[0152] The upper surface of the piezoelectric-side terminal 40 is
formed below the upper surface of the frame conductor 39, and the
lower surface of the piezoelectric-side terminal 40 is formed above
the lower surface of the frame conductor 39. That is, the
piezoelectric-side terminal 40 is formed thinner than the frame
conductor 39.
[0153] On the upper surface of the outer peripheral end portion of
the piezoelectric-side terminal 40, a connecting portion 45 is
formed.
[0154] The connecting portion 45 is inclined to the upper surface
of the frame conductor 39 so as to be gradually thickened with
distance from a radially inner portion toward a radially outer
portion.
[0155] The lower surface of the outer peripheral end portion of the
piezoelectric-side terminal 40 is formed with a stepped portion
42.
[0156] The stepped portion 42 is formed resulting from the height
difference between the lower surface of the piezoelectric-side
terminal 40 and the lower surface of the frame conductor 39 in an
up-down direction.
[0157] As shown in FIGS. 3 and 4, the piezoelectric-side terminal
40 is provided with projecting portions 51 projecting downward from
the lower surface thereof.
[0158] Specifically, as shown in FIGS. 4 and 7, the plurality of
(e.g., four) projecting portions 51 are formed to be spaced apart
from each other in the front-rear direction into a stripe (striped)
pattern in bottom view. Each of the projecting portions 51 is in
the form of a projected rim extending along the widthwise direction
and has the both widthwise end portions thereof in contact with the
peripheral surface of the base opening 37 of the insulating base
layer 28, as shown in FIG. 5.
[0159] As shown in FIG. 4, the lower surface of each of the
projecting portions 51 is formed to be located above the lower
surface of the insulating base layer 28.
[0160] Note that the individual projecting portions 51 have the
side surfaces thereof defined as projecting-portion side surfaces
52 and the lower surfaces thereof defined as projecting-portion
bottom surfaces 53.
[0161] The individual projecting-portion bottom surfaces 53 have
covering base layers 54 which are provided thereon as an example of
the covering layer and the first covering layer so as to cover the
projecting portions 51 from therebelow.
[0162] As shown in FIG. 7, each of the covering base layers 54 is
formed to have the same shape as that of the projecting portion 51
when projected in the up-down direction. Also, as shown in FIG. 5,
the covering base layer 54 is formed such that the upper surface
thereof is bonded to the projecting-portion bottom surface 53 and
the lower surface thereof is at the same height as that of the
lower surface of the insulating base layer 28. The both widthwise
end portions of the covering base layer 54 are continued to the
insulating base layer 28.
[0163] The covering base layers 54 are formed of the same
insulating material as the insulating material of the insulating
base layer 28.
[0164] Note that, as shown in FIG. 4, the covering base layers 54
have the side surfaces thereof defined as covering-base side
surfaces 55 and the lower surfaces thereof defined as covering-base
bottom surfaces 56.
[0165] Note that the upper surface portions of each of the
piezoelectric-side terminals 40 which overlap the projecting
portions 51 when projected in the up-down direction are formed with
protruding portions 43 which are upwardly protruding by the
thicknesses of the covering base layers 54 (described later).
[0166] Also, when projected in the up-down direction, the lower
surface portions of the piezoelectric-side terminal 40 other than
the projecting portions 51 are defined as terminal exposed surfaces
44 each formed of a flat surface. That is, at the lower surface of
the piezoelectric-side terminal 40, the terminal exposed surfaces
44 are exposed from the base opening 37 of the insulating base
layer 28 and the support opening 35 of the support pad 34.
[0167] In the pad portion 33, as shown in FIGS. 4 and 6, the
insulating cover layer 29 includes a cover outer peripheral portion
60 and a cover inner peripheral portion 61.
[0168] As shown in FIG. 6, the cover outer peripheral portion 60 is
formed in a generally annular (ring) shape in plan view which
covers the outer peripheral surface of the frame conductor 39. The
cover outer peripheral portion 60 is formed such that the outer
diameter thereof is slightly smaller than the outer diameter of the
insulating base layer 28.
[0169] As shown in FIG. 4, the cover inner peripheral portion 61 is
formed so as to inwardly project from the inner peripheral surface
of the upper portion of the cover outer peripheral portion 60 and
cover the upper surface of the frame conductor 39. The center
portion of the cover inner peripheral portion 61 is formed with a
cover opening 62 having a generally circular shape in plan view and
extending therethrough in the thickness direction. The cover inner
peripheral portion 61 is formed such that the diameter of the cover
opening 62 thereof is generally the same as the inner diameter of
the insulating base layer 28 (diameter of the base opening 37).
[0170] From the cover opening 62, the upper surface of the
piezoelectric-side terminal 40 is exposed.
[0171] The dimensions of the pad portion 33 are selectively
determined appropriately. As shown in FIG. 7, the outer diameter
(maximum length) of the support pad 34 is in a range of, e.g., 100
to 1000 .mu.m, and the inner diameter of the support pad 34
(diameter of the support opening 35) is in a range of, e.g., 50 to
990 .mu.m.
[0172] As shown in FIG. 6, the outer diameter (maximum length) of
the insulating base layer 28 is in a range of, e.g., 100 to 1000
.mu.m and, as shown in FIG. 7, the inner diameter of the insulating
base layer 28 (diameter of the base opening 37) is the same as the
inner diameter of the support pad 34 (diameter of the support
opening 35).
[0173] Also, as shown in FIG. 6, the outer diameter (maximum
length) of the frame conductor 39 of the conductive pattern 19 is
in a range of, e.g., 90 to 990 .mu.m and, as shown in FIG. 7, the
inner diameter of the frame conductor 39 of the conductive pattern
19 (outer diameter of the piezoelectric-side terminal 40) is
generally the same as the diameter of the base opening 37 and the
diameter of the support opening 35.
[0174] Also, the dimensions of the frame conductor 39 and the
piezoelectric-side terminal 40 in the conductive pattern 19 are
selectively determined appropriately. As shown in FIG. 4, the
thickness of the frame conductor 39 is the same as the thickness of
the conductive pattern 19 (including the wires 25, the front-side
terminals 26, and the rear-side terminals 27), and the thickness of
the piezoelectric-side terminal 40 (height of the
piezoelectric-side terminal 40 in the up-down direction from the
upper surface thereof except for the protruding portions 43 to the
terminal exposed surfaces 44) is in a range of 2 to 10 .mu.m, or
preferably 3 to 7 .mu.m.
[0175] The ratio of the thickness of the piezoelectric-side
terminal 40 to the thickness of the frame conductor 39 is in a
range of, e.g., 8/10 to 2/10, or preferably 6/10 to 3/10.
[0176] The thickness L1 of the projecting portion 51 (height of the
projecting-portion side surface 52 in the up-down direction) is in
a range of 2 to 8 .mu.m, or preferably 3 to 7 .mu.m. The thickness
L2 of the covering base layer 54 (height of the covering-base side
surface 55 in the up-down direction) is in a range of 1 to 5 .mu.m,
or preferably 2 to 4 .mu.m.
[0177] The total sum L3 of the thickness L1 of the projecting
portion 51 and the thickness L2 of the covering base layer 54 is in
a range of 3 to 12 .mu.m, or preferably 5 to 8 .mu.m.
[0178] The ratio (=L2/L1) of the thickness L2 of the covering base
layer 54 to the thickness L1 of the projecting portion 51 is in a
range of, e.g., 1/8 to 5/2, or preferably 2/5 to 4/5.
[0179] Note that, when the total sum L3 is under the range shown
above, it may be impossible to sufficiently increase the adhesive
area between the piezoelectric-side terminal 40 and the conductive
adhesive 46 (see FIG. 3) and sufficiently improve the adhesive
force therebetween.
[0180] The height L4 of the stepped portion 42 in the up-down
direction is in a range of, e.g., 1 to 5 .mu.m, or preferably 2 to
4 .mu.m.
[0181] The length W1 of each of the projecting portions 51 in the
front-rear direction (length of each of the covering base layers 54
in the front-rear direction) is in a range of 5 to 50 .mu.m, or
preferably 10 to 30 .mu.m. The distance W2 between the adjacent
projecting portions 51 is in a range of 5 to 50 .mu.m, or
preferably 10 to 30 .mu.m.
[0182] Note that the total sum W3 of the length W1 of each of the
projecting portions 51 in the front-rear direction and the distance
W2 between the adjacent projecting portions 51 in the front-rear
direction is in a range of 10 to 100 .mu.m, or preferably 20 to 60
.mu.m.
[0183] The ratio (=W2/W1) of the distance W2 between the adjacent
projecting portions 51 to the length W1 of the projecting portion
51 in the front-rear direction is in a range of, e.g., 50/5 to
20/20, or preferably 40/10 to 30/20.
[0184] The ratio (=S2/S1) of the area S2 of the terminal exposed
surface 44 to the area S1 of the projecting-portion bottom surface
53 of the projecting portion 51 is in a range of, e.g., 10/1 to
10/5, or preferably 10/2 to 10/4.
[0185] As shown in FIGS. 6 and 7, the joint portion 41 extends
between one widthwise end portion of the middle portion of the
linear portion 20 in the front-rear direction and the other
widthwise end portion of the pad portion 33.
[0186] The joint portion 41 is formed in a generally rectangular
shape in plan view extending in the widthwise direction and having
a width smaller than the outer diameter (length in the front-rear
direction shorter than that) of the pad portion 33.
[0187] As shown in FIGS. 5 and 6, the joint portion 41 includes the
insulating base layer 28, the power-source wire 25B formed on the
insulating base layer 28, and the insulating cover layer 29 formed
so as to cover the power-source wire 25B.
[0188] In the joint portion 41, as shown in FIG. 6, the insulating
base layer 28 is formed in a shape corresponding to the outer shape
of the joint portion 41. The insulating base layer 28 in the joint
portion 41 is formed to be continued to the insulating base layer
28 in the linear portion 20 and to the insulating base layer 28 in
the pad portion 33.
[0189] The power-source wire 25B in the joint portion 41 is formed
so as to extend along the widthwise direction, and formed to be
continued to the power-source wire 25B in the linear portion 20 and
to the other widthwise end portion of the frame conductor 39 in the
pad portion 33.
[0190] In the joint portion 41, the insulating cover layer 29 is
formed in a pattern covering the upper surface and side surfaces of
the power-source wire 25B and exposing the upper surfaces of the
both end portions of the insulating base layer 28 in the front-rear
direction.
[0191] Note that, in the suspension board with circuit 3, as shown
in FIGS. 3 and 5, protective thin films 47 are formed on the
respective surfaces of the individual terminals, which are
specifically the front-side terminals 26 (see FIG. 1), the
rear-side terminals 27 (see FIG. 1), the piezoelectric-side
terminal 40, and the frame conductor 39.
[0192] In the pad portion 33, the protective thin films 47 are
formed over the upper surface of the piezoelectric-side terminal 40
(including the protruding portions 43 and the connecting portion
45), the projecting-portion side surfaces 52 of the projecting
portions 51, the stepped portion 42, and the terminal exposed
surfaces 44.
[0193] The protective thin films 47 are formed of a metal material
such as, e.g., nickel or gold. Preferably, the protective thin
films 47 are formed of nickel. The thickness of the protective thin
film 47 is in a range of, e.g., 0.05 to 0.1 .mu.m.
[0194] Next, a producing method of the assembly 1 is described.
[0195] To produce the assembly 1, each of the suspension board with
circuit 3, the support plate 2, and the piezoelectric elements 5 is
prepared first.
[0196] Next, a method of preparing (producing) the suspension board
with circuit 3 is described with reference to FIGS. 8 and 9.
[0197] In the method, as shown in FIG. 8(a), the metal supporting
board 18 is prepared first.
[0198] Next, as shown in FIG. 8(b), the insulating base layer 28
and the covering base layers 54 are simultaneously formed on the
upper surface (on one side in the thickness direction in the
production process views of FIGS. 8 and 9, which similarly applies
to the following) of the metal supporting board 18.
[0199] In each of the pad portions 33, the insulating base layer 28
is formed in a pattern corresponding to the piezoelectric-side
terminals 40 and the frame conductors 39 which are subsequently
formed on the upper surface of the metal supporting board 18, while
the covering base layers 54 are formed in a pattern corresponding
to the projecting portions 51 on the upper surface of the metal
supporting board 18.
[0200] The covering base layers 54 are formed thinner than the
insulating base layer. At this time, the thickness of the covering
base layer 54 is in a range of, e.g., 10 to 50% of the thickness of
the insulating base layer 28, specifically in a range of 1 to 5
.mu.m.
[0201] Specifically, to form the insulating base layer 28 and the
covering base layers 54, e.g., a varnish of a photosensitive
insulating material is first applied to the upper surface of the
metal supporting board 18 and dried to form a photosensitive base
coating.
[0202] Next, the photosensitive base coating is subjected to
exposure (gradation exposure) via a gradation exposure photomask
not shown. The gradation exposure photomask includes light
shielding portions, light semi-transmitting portions, and a light
full transmitting portion in a pattern. The light full transmitting
portion is caused to face the portion of the base coating in which
the insulating base layer 28 is formed, the light semi-transmitting
portions are caused to face the portions of the base coating in
which the covering base layers 54 are formed, and the light
shielding portions are caused to face the portions of the base
coating in which neither the insulating base layer 28 nor the
covering base layer 54 is formed.
[0203] Thereafter, the base coating subjected to the gradation
exposure is developed, and cured by heating as necessary to form
the insulating base layer 28 and the covering base layers 54.
[0204] Next, as shown in FIG. 8(c), the conductive layer 19 is
formed over the upper surface of the insulating base layer 28 by an
additive method or a subtractive method. Preferably, the conductive
pattern 19 is formed by the additive method.
[0205] That is, as shown in FIG. 1, the conductive pattern 19 is
formed over the upper surface of the insulating base layer 28 so as
to be provided with the wires 25, and the front-side terminals 26,
the rear-side terminals 27, and the piezoelectric-side terminals 40
which are continued thereto.
[0206] In each of the pad portions 33, as shown in FIG. 8(c), the
conductive pattern 19 is formed by the method described above so as
to cover the inner peripheral portion of the insulating base layer
28, the upper surface of the metal supporting board 18 exposed from
the insulating base layer 28 and the covering base layers 54, and
the upper surfaces of the covering base layers 54.
[0207] Specifically, in the pad portion 33, the conductive pattern
19 is formed to follow the upper surface of the metal supporting
board 18 exposed from the insulating base layer 28 and the covering
base layers 54 and have the same thickness throughout a plane
direction.
[0208] However, at this stage, the upper surface of the
piezoelectric-side terminal 40 of the conductive pattern 19 is
formed with the protruding portions 43 corresponding to the
covering base layers 54, but the lower surface thereof has not been
formed with the projecting portions 51.
[0209] Thus, on the upper surface of the metal supporting board 18,
the conductive pattern 19 is laminated.
[0210] Next, as shown in FIGS. 5 and 6, the insulating cover layer
29 is formed in the foregoing pattern covering the conductive
pattern 19 so as to expose the upper surfaces of the front-side
terminals 26, the rear-side terminals 27, and the
piezoelectric-side terminals 40.
[0211] Specifically, to the entire upper surface of the metal
supporting board 18 including the conductive pattern 19 and the
insulating base layer 28, a varnish of a photosensitive insulating
material is applied, dried, exposed to light, developed, and then
cured by heating.
[0212] Next, as shown in FIG. 9(d), the metal supporting board 18
is trimmed and formed to be provided with the wiring portion 16,
the front portion 15, the rear portion 17, and the support pads 34.
For the trimming, e.g., an etching method such as, e.g., dry
etching (e.g., plasma etching) or wet etching (e.g., chemical
etching), drilling perforation, laser processing, or the like is
used. Preferably, wet etching is used.
[0213] In each of the pad portions 33, the metal supporting board
18 is formed with the support pad 34 and also with the support
opening 35.
[0214] Next, as shown in FIG. 9(e), the piezoelectric-side terminal
40 exposed from the support opening 35 is partly removed.
[0215] The piezoelectric-side terminal 40 is partly removed by,
e.g., etching, or preferably wet etching using the covering base
layers 54 as an etching resist.
[0216] In this manner, the piezoelectric-side terminal 40 is formed
with the projecting portions 51, and the terminal exposed surfaces
44 are exposed from the base opening 37. That is, the
piezoelectric-side terminal 40 is formed in a pattern.
[0217] By also removing the piezoelectric-side terminal 40 between
the adjacent covering base layers 54, the covering-base side
surfaces 55 of the covering base layers 54 are exposed, and the
covering base layers 54 are formed so as to cover the projecting
portions 51 from therebelow.
[0218] Thereafter, as shown in FIG. 9(f), the protective thin films
47 are formed on the surfaces of the front-side terminals 26 (see
FIG. 1), the rear-side terminals 27 (see FIG. 1), and the
piezoelectric-side terminals 40 by, e.g., plating, or preferably by
electroless plating.
[0219] In this manner, the suspension board with circuit 3 is
prepared (produced).
[0220] Next, as shown in FIGS. 1 and 2, the suspension board with
circuit 3, the support plate 2, and the piezoelectric elements 5
are assembled.
[0221] First, the suspension board with circuit 3 is disposed on
the upper surface of the support plate 2. Specifically, as shown in
FIG. 1, the suspension board with circuit 3 is fixed to the support
plate 2 by means of, e.g., welding, an adhesive, or the like such
that the linear portion 20 of the wiring portion 16 traverses the
widthwise middle portion of the plate opening 12, the bent portion
21 of the wiring portion 16 is disposed on the one widthwise end
portion and front end portion of the rear plate portion 9, and the
front portion 15 of the wiring portion 16 is disposed on the
widthwise middle portion of the load beam portion 8 to extend in
the front-rear direction of the load beam portion 8.
[0222] Thereafter, as shown in FIG. 3, each of the piezoelectric
elements 5 is fixed to the support plate 2, while the piezoelectric
terminal 48 of the piezoelectric element 5 is electrically
connected to the piezoelectric-side terminal 40.
[0223] To fix the piezoelectric element 5 to the support plate 2,
the adhesive layers 31 are disposed on the attachment regions 13 of
the actuator plate portion 6 and, via the adhesive layers 31, the
both end portions of the piezoelectric element 5 in the front-rear
direction are attached to the attachment regions 13. As shown in
FIG. 1, the piezoelectric elements 5 are disposed in the plate
opening 12 and on the both widthwise outsides of the linear portion
20 of the suspension board with circuit 3 to be spaced apart
therefrom.
[0224] Then, as shown in FIGS. 3 and 5, the piezoelectric-side
terminal 40 of the suspension board with circuit 3 is electrically
connected to the piezoelectric terminal 48 of the piezoelectric
element 5 via the conductive adhesive 46. Specifically, between the
piezoelectric-side terminal 40 and the piezoelectric terminal 48,
the conductive adhesive 46 is interposed and, by heating the
conductive adhesive 46, the piezoelectric-side terminal 40, and the
piezoelectric terminal 48 to, e.g., a relatively low temperature
(specifically in a range of 100 to 200.degree. C.), the
piezoelectric-side terminal 40 and the piezoelectric terminal 48
are bonded to each other. This provides electrical connection
between the piezoelectric-side terminal 40 and the piezoelectric
terminal 48.
[0225] The conductive adhesive 46 is a connection medium which
exhibits an adhesive effect when heated at a relatively low
temperature (in a range of, e.g., 100 to 200.degree. C.). The
connection medium is made of, e.g., a conductive paste such as a
silver paste, a low-melting-point metal such as an eutectic alloy
(tin-based alloy) such as, e.g., a tin-bismuth alloy or a
tin-indium alloy, or the like. Preferably, the connection medium is
formed of a conductive paste.
[0226] The piezoelectric-side terminal 40 is electrically connected
to the piezoelectric terminal 48 of the piezoelectric element 5 via
the conductive adhesive 46 and is also bonded to the piezoelectric
terminal 48.
[0227] In addition, as shown in FIGS. 1 and 2, the slider 22
mounting the magnetic head (not shown) is mounted on the gimbal 23
to electrically connect the magnetic head (not shown) and the
front-side terminals 26.
[0228] Moreover, the read/write board (not shown) is electrically
connected to the external terminals 27A, and the power source (not
shown) is electrically connected to the power-source-side terminals
27B.
[0229] Furthermore, the drive coil (not shown) is attached to the
base plate portion 7.
[0230] In this manner, the assembly 1 is obtained. The obtained
assembly 1 is mounted in the hard disk drive (not shown).
[0231] In the hard disk drive, the slider 22 of the assembly 1
circumferentially travels relative to a rotating hard disk in the
form of a circular plate, while being floated over the surface of
the hard disk with a minute gap being held therebetween. Meanwhile,
the magnetic head (not shown) of the assembly 1 reads/writes
information, while moving in the radial direction of the hard disk
based on driving by the drive coil.
[0232] In addition, by the extension/contraction of the
piezoelectric elements 5, the position of the magnetic head
relative to the hard disk drive is accurately and finely
adjusted.
[0233] That is, electricity is supplied from the power source (not
shown) to each of the piezoelectric elements 5 via the
power-source-side terminal 27B, the power-source wire 25B, and the
piezoelectric-side terminal 40. The voltage of the electricity
supplied to each of the piezoelectric elements 5 is controlled to
control the extension/contraction of the piezoelectric element 5.
The front end portion of the rear plate portion 9 and the rear end
portion of the front plate portion 10 go farther away from and come
closer to each other, while being flexibly supported on the
flexible portion 11. Therefore, when a voltage for extension is
applied to one of the piezoelectric elements 5 and a voltage for
contraction is applied to the other piezoelectric element 5, the
front plate portion 10 and the load beam portion 8 swing around the
widthwise middle point of the front end portion of the rear plate
portion 9 toward the other widthwise side. At the same time, the
suspension board with circuit 3 and the slider 22 which are fixed
to the load beam portion 8 swing toward the other widthwise
side.
[0234] On the other hand, when the voltage for contraction is
applied to the one piezoelectric element 5 and the voltage for
extension is applied to the other piezoelectric element 5, the
front plate portion 10 and the load beam portion 8 swing in a
direction opposite to the direction described above.
[0235] In the suspension board with circuit 3, as shown in FIG. 3,
each of the piezoelectric-side terminals 40 is formed with the
projecting downward portions 51 and the covering base layers 54
covering the projecting-portion bottom surfaces 53 of the
projecting portions 51.
[0236] As a result, due to the projecting portions 51 formed at the
lower surface of the piezoelectric-side terminal 40 and the
covering base layers 54 formed at the projecting-portion bottom
surfaces 53 of the projecting portions 51 (i.e., by the area of the
projecting-portion side surfaces 52 and the covering-base side
surfaces 55), compared to the case where the entire lower surface
of the piezoelectric-side terminal 40 is the terminal exposed
surface 44, the area of the piezoelectric-side terminal 40 to be
connected to the piezoelectric element 5 can be increased.
[0237] In particular, the lower surface of the piezoelectric-side
terminal 40 is formed not only with the projecting portions 51, but
also with the covering base layers 54 formed on the
projecting-portion bottom surfaces 53 of the projecting portions
51. As a result, compared to the case where only the projecting
portions 51 are formed, the area of the piezoelectric-side terminal
40 to be connected to the piezoelectric element 5 can be increased
accordingly by the thicknesses of the covering base layers 54.
[0238] Consequently, the reliability of the connection between the
piezoelectric element 5 and the piezoelectric-side terminal 40 can
be improved.
[0239] In addition, the piezoelectric-side terminal 40 is connected
to the piezoelectric terminal 48 via the conductive adhesive
46.
[0240] At this time, the piezoelectric-side terminal 40 to be
connected to the piezoelectric element 5 is provided with a
sufficient area. This can improve the adhesive force between the
conductive adhesive 46 and the piezoelectric-side terminal 40.
[0241] Therefore, using the conductive adhesive 46, it is possible
to reliably connect the piezoelectric-side terminal 40 and the
piezoelectric element 5.
[0242] Also, from the base opening 37 of the insulating base layer
28, the lower surface of the piezoelectric-side terminal 40 defined
by the base opening 37 is exposed.
[0243] This allows the insulating base layer 28 to suppress a short
circuit between the portion (such as, e.g., the wires 25) of the
conductive pattern 19 other than the piezoelectric-side terminals
40 and another member, and also allows the terminal exposed
surfaces 44 and the projecting-portion side surfaces 52 of the
piezoelectric-side terminal 40 exposed from the base opening 37 to
be electrically connected to the piezoelectric elements 5.
[0244] In addition, the insulating base layer 28 and the covering
base layers 54 are formed of the same insulating material such as a
synthetic resin.
[0245] Therefore, it is possible to bring the covering base layers
54 into close contact with the projecting portions 51 using the
adhesive force between the insulating base layer 28 and the
conductive pattern 19.
[0246] When the conductive adhesive is used, since the insulating
base layer 28 and the covering base layers 54 are formed of the
insulating material (synthetic resin) or the like, an improvement
in the adhesion to the conductive adhesive can also be
achieved.
[0247] Note that, since the insulating base layer 28 and the
covering base layers 54 can be simultaneously formed, the number of
production steps and cost can be reduced.
[0248] Moreover, since the total sum L3 of the thickness L1 of the
projecting portion 51 of the piezoelectric-side terminal 40 and the
thickness L2 of the covering base layer 54 is the same as or larger
than the thickness of the insulating base layer 28, the area of the
piezoelectric-side terminal 40 to be connected to the piezoelectric
element 5 can be further increased.
[0249] Therefore, it is possible to further improve the reliability
of the connection between the piezoelectric element 5 and the
piezoelectric-side terminal 40.
[0250] Furthermore, from the support openings 35 of the metal
supporting board 18, the lower surfaces of the piezoelectric-side
terminals 40 defined by the support openings 35 can be exposed.
[0251] Therefore, it is possible to reinforce the
piezoelectric-side terminals 40 from therebelow with the metal
supporting board 18, ensure the rigidity of the piezoelectric-side
terminals 40, and also connect the piezoelectric-side terminals 40
exposed from the support openings 35 to the piezoelectric elements
5.
[0252] Also, from the cover openings 62 of the insulating cover
layer 29, the upper surfaces of the piezoelectric-side terminals 40
defined by the cover openings 62 are exposed.
[0253] This allows the insulating cover layer 29 to suppress a
short circuit between the portion (such as, e.g., the wires 25) of
the conductive pattern 19 other than the piezoelectric-side
terminals 40 and another member, and also allows the upper surfaces
of the piezoelectric-side terminals 40 to be exposed from the cover
openings 62. Therefore, the upper surfaces of the
piezoelectric-side terminals 40 can also be used for electrical
connection.
[0254] According to the producing method of the wired circuit board
3 shown in FIGS. 8 and 9, first, on the upper surface of the metal
supporting board 18, the covering base layers 54 are laminated and,
on the upper surface of the metal supporting board 18, the
conductive pattern 19 is laminated so as to cover the covering base
layers 54 and form the piezoelectric-side terminals 40. Then, the
metal supporting board 18 is etched to expose the conductive
pattern 19 and the covering-base bottom surfaces 56 of the covering
base layers 54. Subsequently, using the covering base layers 54 as
an etching resist, the piezoelectric-side terminals 40 are etched.
In this manner, it is possible to form the piezoelectric-side
terminals 40 each including the projecting portions 51 projecting
downward from the terminal exposed surfaces 44, and the covering
base layers 54 covering the projecting-portion bottom surfaces 53
of the projecting portions 51 into a pattern.
[0255] According to such a method, the piezoelectric-side terminals
40 can be etched using the covering base layers 54 as an etching
resist. Accordingly, the covering base layers 54 and the projecting
portions 51 can be formed more efficiently than in the case of
forming the covering base layers 54 after forming the projecting
portions 51.
[0256] As a result, it is possible to obtain the suspension board
with circuit 3 which is excellent in the reliability of the
connection with the piezoelectric elements 5.
[0257] Note that, since the insulating base layer 28 and the
covering base layer 54 can be formed simultaneously, it is possible
to efficiently form the insulating base layer 28 and the covering
base layers 54 and simplify the production steps.
[0258] FIG. 10 shows a cross-sectional view of a pad portion of a
suspension board with circuit as another embodiment of the wired
circuit board of the present invention (a form in which support
covering layers are formed under covering base layers). FIG. 11
shows a cross-sectional view of a pad portion of a suspension board
with circuit as still another embodiment of the wired circuit board
of the present invention (a form in which support covering layers
are formed under projecting portions).
[0259] Note that the members corresponding to the individual
components described above are designated by the same reference
numerals in each of the subsequent drawings, and a detailed
description thereof is omitted.
[0260] In the embodiment of FIG. 4, on the respective
projecting-portion bottom surfaces 53 of the individual projecting
portions 51, the covering base layers 54 are formed each as an
example of the covering layer. However, as shown in FIG. 10, it is
also possible to form support covering layers 57 each as an example
of the covering layer and a second covering layer on the respective
covering-base bottom surfaces 56 of the individual covering base
layers 54.
[0261] The support covering layers 57 are formed of the same metal
material as the metal material of the metal supporting board
18.
[0262] Note that the support covering layers 57 have the side
surfaces thereof defined as support-covering side surfaces 58 and
the lower surfaces thereof defined as support-covering bottom
surfaces 59.
[0263] Each of the support covering layers 57 is formed to have the
same shape as that of each of the projecting portions 51 and the
covering base layers 54 when projected in the up-down direction.
The support covering layer 57 is also formed such that the upper
surface thereof comes in contact with the covering-base bottom
surface 56 of the covering base layer 54 and the lower surface
thereof is at the same height as that of the lower surface of the
support pad 34. The both widthwise end portions of the support
covering layer 57 are continued to the support pad 34.
[0264] The thickness L5 of the support covering layer 57 is in a
range of 15 to 50 .mu.m, or preferably 15 to 20 .mu.m.
[0265] It may also be possible to further etch only the support
covering layers 57. In that case, the thickness L5 of the support
covering layer 57 is in a range of 3 to 20 .mu.m, or preferably 5
to 18 .mu.m.
[0266] The ratio (=L5/L3) of the thickness L5 of the support
covering layer 57 to the total sum L3 of the thickness L1 of the
projecting portion 51 and the thickness L2 of the covering base
layer 54 is in a range of, e.g., 20/8 to 15/5, or preferably 18/8
to 18/5.
[0267] In the producing method of the embodiment of FIG. 4, in each
of the pad portions 33, the metal supporting board 18 is etched to
form the support pad 34 and also form the support opening 35 (see
FIG. 9(d)). By contrast, in the producing method of the embodiment
of FIG. 10, in each of the pad portions 33, the metal supporting
board 18 is etched to form the support pad 34 and the support
opening 35, and also form the support covering layers 57 inside the
support opening 35.
[0268] Then, in the producing method of the embodiment of FIG. 4,
using the covering base layers 54 as an etching resist, the
piezoelectric-side terminal 40 is etched to be formed with the
projecting portions 51 (see FIG. 9(e)). By contrast, in the
producing method of the embodiment of FIG. 10, using the support
covering layers 57 as an etching resist, the piezoelectric-side
terminal 40 is etched to be formed with the projecting portions
51.
[0269] In the embodiment of FIG. 10, the same function/effect as in
the embodiment of FIG. 4 is achieved. In addition, at the lower
surface of the piezoelectric-side terminal 40, not only the
projecting portions 51 and the covering base layers 54 formed on
the projecting-portion bottom surfaces 53 of the projecting
portions 51 are formed, but also the support covering layers 57 are
further formed on the covering-base bottom surfaces 56 of the
covering base layer 54. This can further increase the area of the
piezoelectric-side terminal 40 to be connected to the piezoelectric
element 5.
[0270] As a result, it is possible to further improve the
reliability of the connection between the piezoelectric element 5
and the piezoelectric-side terminal 40.
[0271] In addition, using the adhesive force between the metal
supporting board 18 and the insulating base layer 28, the support
covering layers 57 can be brought into close contact with the
covering base layers 54.
[0272] Furthermore, since the metal supporting board 18 and the
support covering layers 57 are formed of the same material, the
metal supporting board 18 and the support covering layers 57 can be
formed simultaneously.
[0273] Therefore, it is possible to reduce the number of the
production steps and cost.
[0274] According to the producing method of the embodiment shown in
FIG. 10, first, on the upper surface of the metal supporting board
18, the covering base layers 54 are laminated and, on the upper
surface of the metal supporting board 18, the conductive pattern 19
is laminated so as to cover the covering base layers 54 and form
the piezoelectric-side terminals 40. Then, the metal supporting
board 18 is etched to form the support openings 35 and the support
covering layers 57 to expose the lower surfaces of the
piezoelectric-side terminals 40. Subsequently, using the support
covering layers 57 as an etching resist, the piezoelectric-side
terminals 40 are etched. In this manner, it is possible to form the
piezoelectric-side terminals 40 each including the projecting
portions 51 projecting downward from the terminal exposed surfaces
44 of the piezoelectric-side terminal 40, the covering base layers
54 covering the projecting-portion bottom surfaces 53 of the
projecting portions 51, and the support covering layers 57 covering
the lower end portions of the covering base layers 54 into a
pattern.
[0275] According to such a method, the piezoelectric-side terminals
40 can be etched using the support covering layers 57 as an etching
resist. Accordingly, the covering base layers 54, the support
covering layers 57, and the projecting portions 51 can be formed
more efficiently than in the case of forming the covering base
layers 54 and the support covering layers 57 after forming the
projecting portions 51.
[0276] As a result, at the lower surfaces of the piezoelectric-side
terminals 40, not only the projecting portions 51 and the covering
base layers 54 formed on the projecting-portion bottom surfaces 53
of the projecting portions 51 can be formed, but also the support
covering layers 57 can be further formed on the covering-base
bottom surfaces 56 of the covering base layer 54. This can further
increase the area of the piezoelectric-side terminal 40 to be
connected to the piezoelectric element 5 due to the
support-covering side surfaces 58 of the support covering layers
57.
[0277] Accordingly, it is possible to easily obtain the suspension
board with circuit 3 which is excellent in the reliability of
connection with the piezoelectric elements 5 at low cost.
[0278] In the embodiment of FIG. 10, on the projecting-portion
bottom surfaces 53 of the projecting portions 51, the covering base
layers 54 and the support covering layers 57 are formed each as an
example of the covering layer. However, as shown in FIG. 11, it is
also possible to form only the support covering layers 57.
[0279] In this case, each of the projecting-portion bottom surfaces
53 of the projecting portions 51 is formed at the same height as
that of the lower surface of the insulating base layer 28.
[0280] In addition, each of the support covering layers 57 is
formed such that the upper surface thereof comes in contact with
the projecting-portion bottom surface 53 of the projecting portion
51 and the lower surface thereof is at the same height as that of
the lower surface of the support pad 34.
[0281] The thickness L1 of the projecting portion 51 is in a range
of 2 to 8 .mu.m, or preferably 4 to 6 .mu.m.
[0282] The thickness L5 of the support covering layer 57 is the
same as in the embodiment of FIG. 10.
[0283] The ratio (=L5/L1) of the thickness L5 of the support
covering layer 57 to the thickness L1 of the projecting portion 51
is in a range of, e.g., 20/6 to 15/3, or preferably 18/6 to
18/3.
[0284] In the producing method of the embodiment of FIG. 10, in
each of the pad portions 33, the insulating base layer 28 is formed
on the upper surface of the metal supporting board 18 into the
pattern corresponding to the piezoelectric-side terminal 40 and the
frame conductor 39, while the covering base layers 54 are formed on
the upper surface of the metal supporting board 18 into the pattern
corresponding to the projecting portions 51. By contrast, in the
embodiment of FIG. 11, only the insulating base layer 28 is
formed.
[0285] Then, in the same manner as in the producing method of the
embodiment of FIG. 10, the metal supporting board 18 is etched to
form the support pad 34 and the support opening 35, while the
support covering layers 57 are formed inside the support opening
35.
[0286] Also, in the same manner as in the producing method of the
embodiment of FIG. 10, using the support covering layers 57 as an
etching resist, the piezoelectric-side terminal 40 is etched to be
formed with the projecting portions 51.
[0287] In the embodiment of FIG. 11, the same function/effect as in
the embodiment of FIG. 10 is achieved. In addition, since the
support covering layers 57 covering the projecting-portion bottom
surfaces 53 of the projecting portions 51 are formed of the same
material as that of the metal supporting board 18, the support
covering layers 57 can be electrically connected to the
piezoelectric element 5.
[0288] As a result, compared to the case where the support covering
layers 57 are formed of an insulating material, the area of the
piezoelectric-side terminal 40 to be electrically connected to the
piezoelectric element 5 can be increased.
[0289] Additionally, according to the producing method of the
embodiment shown in FIG. 11, first, on the upper surface of the
metal supporting board 18, the conductive pattern 19 is laminated
so as to form the piezoelectric-side terminals 40. Then, the metal
supporting board 18 is etched to form the support openings 35 and
the support covering layers 57 to expose the lower surfaces of the
piezoelectric-side terminals 40. Subsequently, using the support
covering layers 57 as an etching resist, the piezoelectric-side
terminals 40 are etched. In this manner, it is possible to form the
piezoelectric-side terminals 40 each including the projecting
portions 51 projecting downward from the terminal exposed surfaces
44 of the piezoelectric-side terminals 40 and the support covering
layers 57 covering the projecting-portion bottom surfaces 53 of the
projecting portions 51 into a pattern.
[0290] According to such a method, the piezoelectric-side terminals
40 can be etched using the support covering layers 57. Therefore,
the support covering layers 57 and the projecting portions 51 can
be formed more efficiently than in the case of forming the support
covering layers 57 after forming the projecting portions 51.
[0291] As a result, the projecting-portion bottom surfaces 53 of
the projecting portions 51 can be covered with the support covering
layers 57 formed of the same metal material as that of the metal
supporting board 18. This allows the piezoelectric elements 51 to
be electrically connected to the support covering layers 57 and
allows the support covering layers 57 to be electrically connected
to the piezoelectric elements 5.
[0292] Therefore, it is possible to easily obtain the suspension
board with circuit 3 which is excellent in the reliability of
connection with the piezoelectric elements 5 at low cost.
[0293] While the illustrative embodiments of the present invention
are provided in the above description, such is for illustrative
purpose only and it is not to be construed limitative. Modification
and variation of the present invention which will be obvious to
those skilled in the art is to be covered by the following
claims.
* * * * *