[12] patent application publication...[12] patent application publication [21] application no.:...

[19] State Intellectual Property Office of the P.R.C [51] Int. Cl7

GG11B 5/48

G11B 21/16 H05K 1/11

[12] Patent Application Publication

[21] Application No.: 00133926.5

[43] Publication Date: 5.30.2001 [11] Publication No.: CN 1297224 A

[22] Filing Date: 11.17.2000 [21] Application No.:

00133926.5

[30] Priority:

[32] 11.19.1999 [33] JP [31] 330484/1999

[32] 3.30.2000 [33] JP [31] 092662/2000

[71] Applicant: NITTO DENKO CORPORATION

Address: Osaka Prefecture, Japan

[72] Inventors: Tadao Ohkawa (JP); Yasuhito Ohwaki

(JP); Shigenori Morita (JP); Toshihiko Omote (JP)

[74] Agent: Shanghai Patent & Trademark Law Office,

LLC

Attorney: Hong Ling

1 Page of Claims, 18 Pages of Specification, 16 Sheets

of Drawings

[54] Title: SUSPENSION BOARD WITH CIRCUIT

[57] Abstract: The present invention is to provide a suspension board with circuit, which achieves sufficient

strength and a simple structure in its terminal for bonding to other terminals, so as to ensure sufficient bonding

reliability. The suspension board with circuit 11 comprises: a suspension board 12, a base layer 13 formed on

the suspension board 12, a conductive layer 14 formed on the base layer 13, and a cover layer 18 covering the

conductive layer 14, wherein an external connection terminal 17 to be bonded to a terminal 28 of a read/write

board 29 is formed without the formation of the suspension board 12 and/or the base layer 13.

Published by INTELLECTUAL PROPERTY PUBLISHING HOUSE

HUTCHINSON EXHIBIT 1005

1

CLAIMS

1. A suspension board with circuit, characterized in that, it comprises a metal support

layer, an insulating layer formed on the metal support layer, and a conductive layer formed

on the insulating layer; moreover, the suspension board with circuit has a terminal portion

formed for connection to an external circuit, wherein the terminal portion is formed without

the formation of the metal support layer and/or the insulating layer.

2. The suspension board with circuit according to claim 1, characterized in that, the

terminal portion is formed substantially by the insulating layer, the conductive layer formed

on the insulating layer, and a pad portion formed on the conductive layer.


terminal portion is formed substantially by the metal support layer, the conductive layer

formed on the metal support layer, and a pad portion formed on the conductive layer.


terminal portion is formed substantially by the conductive layer and a pad portion formed on

the conductive layer.


1

SPECIFICATION

Suspension board with circuit

The present invention relates to a suspension board with circuit, and more particularly to

a suspension board with circuit used in a hard disk driver. 5 A suspension board with circuit used for a hard disk driver is such a circuit board, in

which the suspension board suspending a magnetic head has a wired circuit integrally formed

therewith for connection between the magnetic head and a read/write board and transmission

of read/write signals to be read/written by the magnetic head to the read/write board. Such a

suspension board with circuit can suspend a magnetic head mounted thereon and maintain its 10 optimal suspended position, so that, a minute gap is maintained between the magnetic head

and the disk, against the airflow generated by the relative movement of the magnetic head

and the disk. For this reason, such a suspension board with circuit is widely used.

As shown in FIG. 21, a suspension board with circuit typically comprises: a metal

support board 1 made from a stainless steel foil, a base layer 2 made of an insulating material 15 and formed on the metal support board, a conductive layer 3 which is in a form of a particular

circuit pattern and formed on the base layer 2, and a cover layer 4 made of an insulating

material and for covering the conductive layer 3. In addition, the suspension board has an

external connection terminal 5 formed for connecting the wired circuit in form of a circuit

pattern to a read/write board 9. 20 The external connection terminal 5 has a pad portion 8, which comprises, for example, a

Ni (nickel) plating layer 6 and an Au (gold) plating layer 7, which are formed by sequentially

plating on the exposed conductive layer 3 that is obtained by making an opening to the cover

layer 4. As shown by the phantomline, a terminal 10 of a read/write board and the pad portion

8 overlap each other, and bond to each other in a stacked state by means of, for example, 25 ultrasonic vibration applied from outside of the metal support board 1 (as shown by the arrow

in FIG. 21).

Such a connection exists between the external connection terminal 5 and the terminal 10

of the read/write board 9, since the ultrasonic vibration applied from outside of the metal

support board 1 is transferred from the metal support board 1, via the base layer 2 and the 30 conductive layer 3, to the pad portion 8, the vibration is attenuated till it reaches the pad

portion 8. As a result, the intensity of the attenuated vibration sometimes is insufficient to

cause the terminals to be bonded together, thus sufficient coupling reliability may not be

obtained.

On the other hand, it can be conceived that, ultrasonic vibration is applied from outside 35 of the read/write board 9 and at the one side of the read/write board 9 formed with the

terminal 10; however, the read/write board 9 generally has a relatively large thickness,

therefore the ultrasonic vibration is not easy to be transferred. Therefore, in this case, the

terminals still cannot be bonded to each other with sufficient strength.

An object of the present invention is to provide a suspension board with circuit, which 40 achieves sufficient strength and a simple structure in its terminal for bonding to other

terminals, so as to ensure sufficient bonding reliability.


2

The suspension board with circuit provided by the present invention comprises a metal

support layer, an insulating layer formed on the metal support layer, and a conductive layer

formed on the insulating layer; moreover, the suspension board has a terminal portion formed

for connection to an external circuit, wherein the formed terminal portion does not form the

metal support layer and/or the insulating layer. 5 The suspension board with circuit according to the present invention, since either one of

or both of the metal support layer and the insulating layer are not formed at the terminal

portion, in the case where the terminal portion is bonded to an external circuit, for example,

when an external force such as ultrasonic vibration or the like is applied from outside of the

metal support layer or the insulating layer, the external force such as ultrasonic vibration is 10 transferred to the bonding portion without passing through either one of or both of the metal

support layer and the insulating layer. Thus, the vibration is transferred to the bonding portion,

with extremely less attenuation of the external force. Thus, the two terminals can be bonded

with each other with relative great strength, resulting in improved bonding reliability between

them. 15 In the suspension board with circuit according to the present invention, preferably, the

terminal portion may be formed substantially by the insulating layer, the conductive layer

formed on the insulating layer, and a pad portion formed on the conductive layer; the terminal

portion may be formed substantially by the metal support layer, the conductive layer formed

on the metal support layer, and a pad portion formed on the conductive layer; or, the terminal 20 portion may be formed substantially by the conductive layer and a pad portion formed on the

conductive layer.

FIG. 1 is a plan view illustrating one embodiment of the suspension board with circuit

according to the present invention;

FIG. 2 is a cross-sectional view of the external connection terminal of the suspension 25 board with circuit, taken along a longitudinal direction of the suspension board with circuit

shown in FIG. 1;

FIG. 3 is a cross-sectional view of the external connection terminal of the suspension

board with circuit, taken along a direction orthogonal to the longitudinal direction of the

suspension board with circuit shown in FIG. 1; 30 FIG. 4 is a rear view of the external connection terminal of the suspension board with

circuit shown in FIG. 1;

FIG. 5 gives cross-sectional views showing the steps for preparing a suspension board

and forming a base layer having a specified pattern on the suspension board;

(a) the step of preparing a suspension board; 35 (b) the step of forming a precursor coating of photosensitive polyimide resin on the

suspension board;

(c) the step of forming a specified pattern by exposing and developing the coating

through a photomask; and

(d) the step of forming a base layer by curing the patterned coating, 40 FIG. 6 gives cross-sectional views showing the steps for forming a conductive layer

having a specified circuit pattern on the base layer:

(a) the step of forming a ground on the base layer and the suspension board;

(b) the step of forming a plating-resist layer having a pattern reversing to a specified

circuit pattern, on the ground; 45


3

(c) the step of forming a conductive layer having the specified circuit pattern, on a

portion of the base layer where the plating-resist layer is not formed;

(d) the step of removing the plating-resist layer; and

(e) the step of removing the ground,

FIG. 7 are cross-sectional views showing the steps for forming a thin metal film to 5 protect the surface of the conductive layer having a circuit pattern, and then forming a cover

layer to cover the surface of the conductive layer;

(a) the step of forming a thin metal film on the surface of the conductive layer;

(b) the step of forming a precursor coating of photosensitive polyimide resin, on the base

layer and the thin metal film; 10 (c) the step of patterning the coating by exposing and developing the coating through a

photomask; and

(d) the step of forming a cover layer by curing the patterned coating,

FIG. 8 gives cross-sectional views showing the steps for forming the external connection

terminal; 15 (a) the step of peeling off the thin metal film that is formed on the exposed conductive

layer and the suspension board;

(b) the step of forming a pad portion consisting of a Ni plating layer and an Au plating

layer on the exposed conductive layer; and

(c) the step of forming an opening at a portion of the suspension board corresponding to 20 the pad portion,


board with circuit, taken along a direction orthogonal to the longitudinal direction of a variant

of the suspension board with circuit shown in FIG. 3;

FIG. 10 is a rear view of the external connection terminal of the suspension board with 25 circuit shown in FIG. 9;


board with circuit, taken along the longitudinal direction of the suspension board with circuit

shown in FIG. 2;

FIG. 12 is a cross-sectional view of the external connection terminal of the suspension 30 board with circuit, taken along a direction orthogonal to the longitudinal direction of the

suspension board with circuit shown in FIG. 11;

FIG. 13 is a rear view of the external connection terminal of the suspension board with

circuit shown in FIG. 11;

FIG. 14 gives cross-sectional views showing the steps for forming the external 35 connection terminal of the suspension board with circuit shown in FIG. 11;

(a) the step of preparing a suspension board;

(b) the step of forming a base layer on the suspension board having a particular pattern

other than a portion for formation of a pad;

(c) the step of forming a conductive layer having a particular circuit pattern, 40 FIG. 15 are cross-sectional views showing the steps for forming the external connection

terminal of the suspension board with circuit shown in FIG. 11 to FIG. 14;


4

(d) the step of forming a cover layer;

(e) the step of forming a pad portion; and

(f) the step of cutting the suspension board to enclose the pad portion,


board with circuit, taken along the longitudinal direction of a variant of the suspension board 5 with circuit shown in FIG. 2 and FIG. 11;


board with circuit, taken along a direction orthogonal to the longitudinal direction of the

suspension board with circuit shown in FIG. 16;

FIG. 18 is a rear view of the external connection terminal of the suspension board with 10 circuit shown in FIG. 16;

FIG. 19 are cross-sectional views showing the steps for forming a pad portion of the

external connection terminal of the suspension board with circuit shown in FIG. 16;

(a) the step of forming an opening at a portion of the suspension board corresponding to

the pad portion; 15 (b) the step of peeling off the thin metal film formed on the exposed conductive layer

and the suspension board;

(c) the step of making an opening to the exposed base layer at the opening of the

suspension board, so as to match with the opening of the suspension board;

(d) the step of peeling off the exposed ground obtained by making an opening to the 20 base layer;

(e) the step of forming a pad portion on the front surface of the exposed conductive layer

by electrolytic plating, and simultaneously forming the same plating layer on the back surface

of the exposed conductive layer,

FIG. 20 is a plan view illustrating a short-tail type of the suspension board with circuit; 25 FIG. 21 is a cross-sectional view of an external connection terminal of a conventional

suspension board with circuit;

FIG. 22(a) is a top view of a to-be-bonded board used for assessment; FIG. 22(b) is a

cross-sectional view taken along the line A-A; and

FIG. 23 is a schematic diagram illustrating a 90-degree peeling test. 30 Referring to FIG. 1, it is a plan view illustrating an embodiment of the suspension board

with circuit according to the present invention. The suspension board with circuit has a

magnetic head mounted thereon; the magnetic head is used for a hard disk driver (not shown)

and is suspended so that a minute gap is maintained between the magnetic head and the disk,

against the airflow generated by the relative movement of the magnetic head and the disk. 35 The suspension board with circuit has a wired circuit in a particular form of circuit pattern

integrally formed therewith, for connection between the magnetic head and a read/write

board formed as an external circuit.

In FIG. 1, in the suspension board with circuit 11, a base layer 13 is formed on a

suspension board acting as a metal support layer and extending longitudinally, and the base 40 layer 13 is formed as an insulating layer of an insulating material. On the base layer 13, a

conductive layer 14 in a particular form of circuit pattern is formed. The circuit pattern is

formed by a plurality of wired circuits 14a, 14b, 14c, 14d arranged in parallel and at a


5

predetermined interval. By cutting the front-end portion 12 of the suspension board 12, a

gimbal 15 for mounting the magnetic head therein is formed in the suspension board 12. At

the front end portion of the suspension board 12, a magnetic-head connection terminal 16 is

formed, for connection between the magnetic head and the wired circuits 14a, 14b, 14c, 14d.

At the rear end portion of the suspension board 12, an external connection terminal 17 is 5 formed as a terminal portion for connection between a terminal 28 of a read/write board 29

and the wired circuits 14a, 14b, 14c, 14d.

Although not shown in FIG. 1, in fact, a cover layer 18 made of an insulating material

covers the conductive layer 14.

For example, as shown in FIGS. 2 to 4, in the suspension board with circuit 11, the 10 external connection terminal 17 is formed substantially by the base layer 13, the conductive

layer 14 formed on the base layer 13, and a pad portion 9 formed on the exposed conductive

layer 14 that is obtained by making an opening to the cover layer 18; besides, the suspension

board 12 has an opening formed at the portion where the external connection terminal 17 is

formed. 15 In FIGS. 2 and 3, in the external connection terminal 17, openings are made to the cover

layer 18, so that the openings generally in a rectangular shape are formed at the end of the

wired circuits 14a, 14b, 14c, 14d and corresponding to the wired circuits 14a, 14b, 14c, 14d;

further, a Ni coating layer 26 and an Au plating layer 27, which act as the pad portions 19, are

formed on the exposed conductive layer 14 in each of the openings. Further, as shown in FIG. 20 4, on the suspension board 12, openings 32 are formed, which are generally in a rectangular

shape and generally in the same size as the pad portions 12 and spaced and corresponding to

the pad portions 19. It should be noted that, in FIGS. 2 to 4, a ground 20 and a thin metal film

22 as described hereinbelow are omitted.

Next, referring to FIGS. 5 to 8, the manufacturing process of the suspension board with 25 circuit will be described in detail. On the right of FIGS. 5 to 8, the cross-sectional views,

taken along the longitudinal direction of the suspension board with circuit 11, show the

portion of the suspension board with circuit on which the external connection terminal 17 is

formed. On the left of FIGS. 5 to 8, the cross-sectional views, taken along a direction

orthogonal to the longitudinal direction of the suspension board with circuit 11, show the 30 longitudinal cross sections of the suspension board with circuit 11.

First, as shown in FIG.5, a suspension board 12 is prepared, and a base layer 13 in a

particular form of pattern is formed on the suspension board 12. Preferably, a metal foil or a

metal sheet is used as the suspension board 12. For example, it is preferable to use stainless

steel, 42-alloy, or the like. The suspension board in use preferably has a thickness of 10-60 μm 35 or more preferably a thickness of 15-30 μm, and has a width of 50-500 mm or more preferably

a width of 125-300 mm.

Any insulating material used for the suspension board with circuit, may be used as an

insulating material for forming the base layer 13, without any particular limitation. For

example, such insulating material includes polyimide resin, acrylic resin, polyether nitrile 40 resin, polyether sulfonic resin, polyethylene terephthalate resin, polyethylene naphthalate

resin, polyvinyl chloride resin and other synthetic resins. For these synthetic resins, it is

preferable to use a photosensitive synthetic resin as the base layer. It is more preferable to use


6

a photosensitive polyimide resin.

Then, for example, in the case where a photosensitive polyimide resin is used to form

the base layer 13 in form of a specified pattern on the suspension board 12, firstly, a liquid

solution of a precursor made of photosensitive polyimide resin (polyamic acid resin (a

photosensitive polyamic acid resin, unless otherwise specified)) as shown in FIG. 5(b) is 5 applied to the entire surface of the suspension board 12 prepared as shown in FIG. 5(a), and

then, by heating to 60-150℃, more preferably to 80-120℃, a coating 13a of the precursor

made of photosensitive polyimide resin is formed.

Then, as shown in FIG. 5(c), the coating 13a is exposed through a photomask 24. If

necessary, the exposure portion is heated to a certain temperature. Thereafter, the coating is 10 developed to cause the coating 13 to form a specified pattern. Preferably, the radiation light

irradiating through the photomask has an exposure wavelength of 300-450 nm or preferably

an exposure wavelength of 350-420 nm. Preferably, the total amount of exposure is 100-1000

mJ/cm2, or more preferably 200-700 mJ/cm

2. Further, for the irradiated exposure portion of the

coating 13a, in the case where it is heated to a temperature, for example, higher than 130℃ 15 and lower than 150℃, it is solubilized (a positive type) in the next processing procedure, on

the other hand, in the case where it is heated to a temperature, for example, higher than 150℃

and lower than 180℃, it is not solubilized (a negative type) in the next processing procedure. A known developer such as an alkaline developer may be used for the developing procedure

by any known method such as a dipping process, a spraying process and the like. Preferably, 20 the manufacturing method uses a negative type to produce a circuit pattern. FIG. 5 shows one

embodiment in which negative-type processing steps are used to form a circuit pattern.

As shown in FIG. 5(d), finally, the thus formed patterned precursor coating 13a of

polyimide resin is heated to 250℃ or higher to be cured (imidized), thereby forming the base

layer 13 of polyimide having a form of a specified pattern. 25 In the case of not using photosensitive resin, for example, resin may be applied in a

specified pattern to the suspension board 12 or may be bonded thereto in a form of a dry film.

Preferably, the thus formed base layer 13 has a thickness of 2-30 μm, for example, or

preferably a thickness of 5-20 μm.

Next, the conductive layer 14 is formed in a form of a specified circuit pattern on the 30 base layer 13. The conductive layer 14 formed in a form of a specified pattern is made of a

conductive material. Any electrically conductive material may be used, without any particular

limitation, as long as it can be used as an electrically conductive material for the suspension

board with circuit. For example, the conductive materials that may be used include Cu

(copper), Ni (nickel), Au (gold), and solder or alloy thereof. Preferably, copper is used as the 35 conductive material. To form the conductive layer 14 having a specified circuit pattern, any

known processes for forming a pattern, such as subtractive processes, additive processes and

semi-additive processes, may be utilized to form the conductive layer 14 having a specified

pattern.

In a subtractive process, firstly, the conductive layer 14 is laminated on the entire 40 surface of the base layer 13 by an adhesive layer as required, then resist is formed on the

conductive layer 14 so as to match with the specified circuit pattern. With the resist as a


7

protective layer, the conductive layer 14 is etched, thereafter the resist is removed from the

conductive layer 14.

In an additive process, firstly, a plating-resist layer having a pattern reverse to a

specified circuit pattern is formed on the base layer 13. Then, by plating the surface of the

base layer 13 on which the plating-resist layer is not formed, the conductive layer 14 having a 5 specified circuit pattern is formed. Thereafter, the plating-resist layer is removed.

In a semi-additive process, firstly, a thin film of a conductive material is formed as a

ground on the base layer 13, then, a plating-resist layer having a pattern reverse to a specified

circuit pattern is formed on the ground. Then, by plating the surface of the ground on which

the plating-resist layer is not formed, the conductive layer 14 having a specified circuit 10 pattern is formed. Thereafter, the plating-resist layer and the ground on which the plating-

resist layer is laminated are removed.

Among these patterning processes, preferably, a semi-additive process as shown in FIG.

6 is used. Specifically, firstly, as shown in FIG. 6(a), a thin film of a conductive material for

formation of a ground 20 is formed on the entire surfaces of the suspension board 12 and the 15 base layer 13. Preferably, the ground 20 is formed by a vacuum deposition process or

preferably by a sputter deposition process. Preferably, Cr (chromium) and Cu (copper) are

used as the conductive materials for forming the ground 20. More specifically, a Cr thin film

and a Cu thin film are sequentially formed on the entire surfaces of the suspension board 12

and the base layer 13, preferably by a sputter deposition process. Preferably, the Cr thin film 20 has a thickness of 100-600Å, and the Cu thin film has a thickness of 500-2000Å.

Next, as shown in FIG. 6(b), a plating-resist layer 21 having a pattern reverse to a

specified circuit pattern is formed on the ground 20. The plating-resist layer 21 having a form

of a specified resist pattern may be formed, for example, through a known process by using a

dry film resist. Then, as shown in FIG. 6(c), by plating the portion of the base layer 13 on 25 which the plating-resist layer 21 is not formed, the conductive layer 14 having a specified

circuit pattern is formed. Although both electrolytic plating and electroless plating can be

used, electrolytic plating is preferred. Among them, electrolytic copper plating is more

preferred. For example, a circuit pattern is formed in the form of the pattern constituted by the

plurality of wired circuits 14a, 14b, 14c, 14d arranged in parallel and at a predetermined 30 interval as shown in FIG. 1. The conductive layer 14 has, for example, a thickness of 2-20 μm,

or preferably a thickness of 5-18 μm. Each of the wired circuits 14a, 14b, 14c, 14d has, for

example, a width of 10-500 μm, or preferably a width of 30-200 μm. The interval between the

wired circuits 14a, 14b, 14c, 14d is, for example, 10-200 μm, or preferably 30-100 μm.

Then, as shown in FIG. 6(d), the plating-resist layer 21 is removed by peeling it off or 35 by a known etching process such as a chemical etching process (wet etching) or the like. Thereafter, as shown in FIG. 6(e), likewise, the portion of the ground 20 on which the

plating-resist layer 21 is formed, is removed by a known etching process such as a chemical

etching process (wet etching) or the like. Through these processing steps, the conductive layer

14 having a form of a specified circuit pattern is formed on the base layer 13. 40


8

Next, after the surface of the conductive layer 14 is protected by a thin metal film 22, as

shown in FIG. 7, the conductive layer 14 is covered by a cover layer 18 formed of an

insulating material. Specifically, as shown in FIG. 7(a), firstly, a thin metal film 22 is formed

on the surface of the conductive layer 14 and the front surface of the suspension board 12. Preferably, the thin metal film 22 is formed in the form a hard and thin Ni film by electroless 5 nickel plating. It is only required for the thin Ni film 22 to have a sufficient thickness to

prevent exposing of the conductive layer 14. For example, the thin Ni film 22 may have a

thickness of about 0.05 to about 0.1 μm.

Next, the cover layer 18 in form of a specified pattern is formed for covering the

conductive layer 14. The same insulating material is used as the insulating material for 10 forming the cover layer 18. Preferably, photosensitive polyimide resin is used.

In the case where photosensitive polyimide resin is used to form the cover layer 18, as

shown in FIG. 7(b), a liquid solution of a precursor made of photosensitive polyimide resin

(polyamic acid resin) is applied to the entire surfaces of the base layer 13 and the thin metal

film 22, and then, by heating to, for example, 60-150℃, more preferably to 80-120℃, a 15 coating 18a of the precursor made of photosensitive polyimide resin is formed. Then, as

shown in FIG. 7(c), the coating 18a is exposed through a photomask 25. If necessary, the

exposure portion is heated to a certain temperature. Thereafter, the coating 18a is developed

to form a pattern, thus the coating 18a may be used to cover the conductive layer 14. As

shown in FIG. 7(c), in the case of using the coating 18a to form a pattern, the portion of the 20 conductive layer 14 that is to be formed as a pad portion 19 is exposed. The coating 18a may

undergo exposing and developing under the same conditions as those used for exposing and

developing of the base layer 13. Preferably, the pattern of the coating is formed by means of a

negative image. FIG. 7 shows an embodiment, in which the pattern of the coating is formed

by means of a negative image. 25 As shown in FIG. 7(d), finally, the thus formed patterned precursor coating 18a of

polyimide resin is heated to 250℃ or higher to be cured (imidized), thereby forming the

cover layer 18 of polyimide on the conductive layer 14. The cover layer 18 has a thickness of

1-30 μm, or preferably a thickness of 2-5 μm.

Subsequently, as shown in FIG. 8, the pad portion 19 is formed. As shown in FIG. 8(a), 30 before the formation of the pad portion 19, firstly, the exposed thin metal film 22 that is

obtained by making an opening to the cover layer 18 at the portion where the pad portion 19

is to be formed, is peeled. Also, the thin metal film 22 formed on the suspension board 12 is

peeled. Then, the pad portion 19 is formed on the surface of the exposed conductive layer 14

by plating. Any metal can be used for plating, without any particular limitation, as long as it 35 can form the terminal of the suspension board with circuit. For example, preferably, Cu, Ni,

Cr and Au are used. For plating, both electrolytic plating and electroless plating can be used,

preferably, electrolytic plating is used. Among them, preferably, chemical plating is used. For

forming the pad portion 19 by electrolytic plating, for example, the suspension board 12 and

the cover layer 18, other than the portion on which the pad portion 19 is to be formed and 40 which subsequently undergoes plating, are completely covered by resist. Thereafter, the resist

is removed. The pad portion 19 may be formed in multi layers. As shown in FIG. 8(b), for

example, preferably, by electrolytic nickel plating and electrolytic gold plating in sequence, a


9

Ni plating layer 26 and an Au plating layer 27 on top of the Ni plating layer 26 are formed. Preferably, the Ni plating layer 26 and the Au plating layer 27 have a thickness of about 1 to

5 μm, respectively.

Then, after removal of the lead wires used in electrolytic nickel plating and electrolytic

gold plating by chemical etching, the suspension board 12 is cut to a predetermined shape as 5 a gimbal 15 by a known process such as chemical etching. At the same time of the cutting

process, generally the suspension board is also cut to a rectangular shape, so that an opening

32 is formed in a portion thereof corresponding to the pad portion 19. Thereafter, after being

washed and dried, the suspension board with circuit 11 as shown in FIG. 1 is obtained.

Although description is not given, the part of the suspension board 12 corresponding to 10 the pad portion 19 has no opening formed, in addition to that, a magnetic-head connection

terminal 16 is formed in the same process of forming the external connection terminal 17.

The thus formed suspension board with circuit 12 has the part of the suspension board

11 that is to be formed as the external connection terminal 17 left to be exposed. As shown in

FIG. 2, for example, in the case where the external connection terminal 17 is bonded to a 15 terminal 28 of a read/write board 29, for example, when ultrasonic vibration or the like

(indicated by the arrow 34 in FIG. 2) is applied from outside of the base layer 13, the

ultrasonic vibration is transferred from the base layer 13 through the conductive layer 14 to

the pad portion 19, without passing through the suspension board 12. Thus, the vibration

transferred to the pad portion 19 has extremely small attenuation. Therefore, the external 20 connection terminal 17 and the terminal 28 of the read/write board 29 can be bonded to each

other with a high strength, resulting in improved bonding reliability between them.

During the above-mentioned process of forming an opening 32 of the suspension board

12 by making openings in the suspension board 12, with the openings being generally in a

rectangular shape and corresponding to each of the pad portions 19 (as shown in FIGS. 3 and 25 4), for example, as shown in FIGS. 9 and 10, the opening 32 can be changed, by forming a

single large rectangular opening which encloses all of the pad portions 19, without the need

of forming openings corresponding to each of the pad portions. In FIG. 10, the opening 32 of

the suspension board 12 is formed in the form of a single rectangular opening which has a

size large enough to contain all the parts corresponding to the respective pad portions 19. It 30 should be note that, in FIGS. 9 and 10, the ground 20 and the thin metal film 22 are omitted.

Considering the strength of the external connection terminal 17, preferably, a plurality of

openings 32 are formed corresponding to each of the pad portions 19 (as shown in FIG. 4),

rather than forming a large rectangular opening 32 as shown in FIG. 10.

As shown in FIGS. 11 to 13, the suspension board with circuit 11 according to the 35 present invention may be modified in such a way that the external connection terminal 17

may be formed substantially by the suspension board 12, the conductive layer 14 formed on

the suspension board 12, and the pad portions 19 formed on the exposed conductive layer 14

that is obtained by making an opening to the cover layer 18. In FIGS. 11 and 12, in such

modification of the external connection terminal 17, no base layer is formed in the portion of 40 the base layer 13 corresponding to the pad portions 19, instead the conductive layer 14 is

formed directly on the suspension board 12. Further, as shown in FIG. 13, the suspension

board 12 is cut by cutting around the portions of the suspension board corresponding to the


10

respective pad portions, and thus a cut portion 33 is formed. It is noted that, in FIGS. 11 to 13,

the ground 20 and the thin metal film 22 are omitted.

For example, in the above-described manufacturing process of the suspension board

with circuit, the external connection terminal 17 may be formed as follows. Firstly, as shown

in FIG. 14(a), in the processes (corresponding to the processes shown in FIGS. 5(a) to 5(d)) 5 of preparing the suspension board 12 and forming the base layer 13 on the suspension board

12, the base layer 13 is formed to define such a pattern that, as shown in FIG. 14(b), no base

layer is formed in the portion of the base layer 13 to be formed as the pad portions 19, in

other words, the pattern is formed with openings generally in a rectangular shape and

corresponding to the respective pad portions 19. Then, in the processes (corresponding to the 10 processes shown in FIGS. 6(a) to 6(d)) of forming the conductive layer 14 having a particular

circuit pattern, as shown in FIG. 14(c), the conductive layer 14 is formed directly in the

portion of the suspension board 12 on which the pad portions 19 are to be formed.

Then, in the processes (corresponding to the processes shown in FIGS. 7(a) to 7(d)) of

forming the cover layer 18, the cover layer 18 is formed to define such a pattern that, as 15 shown in FIG. 15(d), no cover layer is formed in the portion of the cover layer 18 to be

formed as the pad portions 19. Then, in the processes (corresponding to the processes shown

in FIGS. 8(a) to 8(d)) of forming the pad portions 19, the conductive layer 14 exposed

through the cover layer 18 is sequentially subjected to electrolytic nickel plating and

electrolytic gold plating, so that the Ni plating layer 26 and the Au plating layer 27 on top of 20 the Ni plating layer 26 are formed, thereby obtaining the respective pad portions 19. Next, in

the processes (corresponding to the processes shown in FIGS. 8(c)) of cutting the suspension

board 12 into a specified form, as shown in FIG. 15(f), the suspension board 12 is cut by

cutting around the portions of the suspension board corresponding to the respective pad

portions 19, and thus a cut portion 33 is formed. It should be noted that, in FIGS. 14 and 15, 25 the ground 20 and the thin metal film 22 are omitted. The contents that are not given in the

above description are related to the above examples.

In the thus formed suspension board with circuit 11, the portion of the base layer 13 to

be formed as the external connection terminal 17 is exposed. For example, as shown in FIG.

11, in the case where the external connection terminal 17 is bonded to the terminal 28 of the 30 read/write board 29, for example, when ultrasonic vibration or the like (indicated by the

arrow 34 in the Figure) is applied from outside of the suspension board 12, the ultrasonic

vibration is transferred from the suspension board 12 through the conductive layer 14 to the

pad portion 19, without passing through the base layer 13. Thus, the vibration transferred to

the pad portion 19 has extremely small attenuation. Therefore, the external connection 35 terminal 17 and the terminal 28 of the read/write board 29 can be bonded to each other with a

high strength, resulting in improved bonding reliability between them.

As shown in FIGS. 16 to 18, the suspension board with circuit 11 according to the

present invention may be modified in such a way that the external connection terminal 17

may be formed substantially by the conductive layer 14 and the pad portions 19 formed on 40 the exposed conductive layer 14 that is obtained by making an opening to the cover layer 18;

besides, the suspension board 12 and the base layer 13 have an opening formed at the portion

where the external connection terminal 17 is to be formed. Referring to FIGS. 16 and 17, in


11

the external connection terminal 17, an opening is made to the cover layer 18, so that the

cover layer 18 has a single rectangular opening, and the opening is large enough to contain all

the pad portions 19, and further, on the conductive layer 14 exposed through the opening, the

Ni plating layer 26 and the Au plating layer 27 are formed as the pad portion 19, Further, as

shown in FIG. 18, an opening is made to the suspension board 12 and the base layer 13, so 5 that they both have a single rectangular opening 32 which is large enough to contain all of the

pad portions 19; further, on the conductive layer 14 exposed through the opening 32, a

plating layer 35 is formed, which is same as the plating layer of the pad portion 19. It should

be noted that, in FIGS. 16 to 18, the ground 20 and the thin metal film 22 are omitted.

In the above-described manufacturing process of the suspension board with circuit, the 10 external connection terminal 17 may be formed as follows. For example, in the case where

the base layer 13 is formed on the suspension board 12 to define a specified pattern (as shown

in FIG. 5) and then the conductive layer 14 is formed on the base layer 13 to define a

specified circuit pattern (as shown in FIG. 6), as shown in FIG. 7, the conductive layer 14 is

covered by the cover layer 18, and the cover layer 18 is patterned to define a single large 15 rectangular opening which contains all of the pad portions 19, rather than in the processes (as

shown in FIG. 7(c)) of patterning the coating 18a and exposing the conductive layer 14 in the

portion of the coating 18a to be formed as the pad portions 19, that a plurality of individual

openings are formed, which are generally in a rectangular shape and separately formed

corresponding to the respective pad portions 19. 20 Then, in the processes (as shown in FIG. 8) of forming the pad portions 19, the

suspension board 12 is cut to a specified shape as the gimbal 15 by a known process such as

chemical etching. During such cutting, in the meantime, the suspension board is cut to a

single large rectangle, to contain all the pad portions 19 in the portion of the suspension board

corresponding to the respective pad portions 19, so that, as shown in FIG. 19(a), the opening 25 32 is formed. Next, as shown in FIG. 19(b), the thin metal film 22 is peeled off, in which the

exposed thin metal film 22 is obtained by making an opening to the cover layer 18 in the

portion of the cover layer to be formed as the pad portions 19. At the same time of the peeling,

the thin metal film 22 formed on the suspension board is also peeled off. Then, as shown in

FIG. 19(c), according to the opening 32, an opening is made to the base layer 13 exposed 30 through the opening 32 formed by cutting the suspension board 12. (The thus formed opening

of the cover layer 18 also forms the opening 32.) An opening may be made to the base layer

13 by a well-known method such as plasma etching or laser processing or the like. Thereafter,

as shown in FIG. 19(d), by peeling off the ground 20 exposed through the opening made to

the base layer 13, the back surface of the conductive layer 14, which is opposite the front 35 surface of the conductive layer 14 to be formed as the pad portions 19, is exposed. Then, as

shown in FIG. 19(e), the pad portion 19 is formed on the front surface of the exposed

conductive layer 14 by plating, meanwhile, the same plating layer 35 is formed on the both

lateral surfaces and the back surface of the exposed conductive layer 14. It is possible that, in

the same way as above, by electrolytic nickel plating and electrolytic gold plating, the Ni 40 plating layer 26 and the Au plating layer 27 on top of the Ni plating layer 26 are formed,

thereby forming the pad portions 19 and the plating layer 35. Finally, the plating lead wires

used in electrolytic nickel plating and electrolytic gold plating are removed by chemical

etching, thereby obtaining the suspension board with circuit 11. The contents that are not

given in the above description are related to the above examples. 45 In the thus formed suspension board with circuit 11, the portions of the suspension board


12

12 and the base layer 13 to be formed as the external connection terminal 17 are exposed. For

example, as shown in FIG. 16, in the case where the external connection terminal 17 is

bonded to the terminal 28 of the read/write board 29, for example, when ultrasonic vibration

or the like (indicated by the arrow 34 in the FIG. 16) is applied from outside of the plating

board 35, the ultrasonic vibration is transferred from the plating board 35 through the 5 conductive layer 14 to the pad portion 19, without passing through the suspension board 12

and the base layer 13. Thus, the vibration transferred to the pad portions 19 has extremely

small attenuation. Therefore, the external connection terminal 17 and the terminal 28 of the

read/write board 29 can be bonded to each other with a high strength, resulting in improved

bonding reliability between them. Compared with the suspension board with circuit 11 shown 10 in FIGS. 2 to 4 and the suspension board with circuit 11 shown in FIGS. 11 to 13, the

suspension board with circuit 11 shown in FIGS. 16 to 18 has the suspension board 12 and

the base layer 13 exposed, thereby achieving further effective transferring of ultrasonic

vibration, thus producing a further improved bonding strength. In the suspension board with

circuit 11 shown in FIGS. 16 to 18, it is not necessary to particularly distinguish the pad 15 portions 19 and the plating layer 35 from each other. For example, the terminal 28 of the

read/write board 29 may be bonded to the plating layer 35, instead of being bonded to the pad

portions 19.

Although each of the above embodiments of the suspension board with circuit 11 is a so-

called long-tail type (in which the external connection terminal 17 is bonded to the terminal 20 28 of the read/write board 29), the suspension board with circuit according to the present

invention is not necessarily limited thereto. For example, it may be a short-tail type as shown

in FIG. 20. In the short-tail type of suspension board with circuit 11, the suspension board

with circuit 11 is connected via an intermediate board 30 to the read/write board 29, while the

external connection terminal 17 of the suspension board with circuit 11 is connected to the 25 terminal 31 of the intermediate board.

Although in the above embodiments, the pad portions 19 of the external connection

terminal 17 is formed by plating, they may be formed by any other known processes, without

being limited to plating. It is possible that, the pad portion 19, the opening 32 and the cut

portion 33 are formed in a circular or polygonal shape, without being limited to a rectangular 30 shape. Depending on the desired use and the desired application, their shapes may be

appropriately selected.

In the above embodiments, the external connection terminal 17 of the suspension board

with circuit 11 has a flat form, which has advantageous impedance characteristics over the

bump-like external connection terminal of a conventional suspension board with circuit. In 35 the above embodiments, the flat-form external connection terminal 17 of the suspension

board with circuit 11 is bonded in a surface-to-surface relationship to the terminal 28 of the

read /write board 29, resulting in bonding points having smaller changes in their shapes and

their impedance, compared with a bump-like terminal. Thus, signals can be better transmitted

therebetween. For example, impedance characteristics may be estimated by using a time-40 domain reflectometer.

Further, it is possible that, the external connection terminal 17 is bonded to an external

circuit such as the terminal 28 of the read/write board 29 by a known bonding process such as

a hot-press-contact process, without being limited to the process of applying ultrasonic

vibration. 45 Examples

Although hereinafter the present invention will be described in more detail with


13

reference to examples and comparative examples, but the present invention is not limited to

any examples or comparative examples.

Example 1

A liquid solution of polyamic acid resin is applied to a stainless steel foil having a

thickness of 25 μm, then heated at 130℃, thereby forming a coating of polyamic acid resin. 5 Next, the coating is exposed (405 nm, 1500mJ/cm

2) through a photomask. The exposed

portion is heated to 180℃, and then developed by using an alkaline developer, thereby

causing the coating to form a pattern by means of a negative image. Subsequently, the

patterned polyamic acid resin coating is heated at 350℃ to be cured (imidized), thereby

forming a base layer of polyamic acid resin having a specified pattern and a thickness of 15 10 μm.

Then, through a sputter deposition process, a thin Cr film having a thickness of 300Å

and a thin Cu film having a thickness of 700Å are sequentially formed on the entire surfaces

of the base layer and the stainless steel foil. Thereafter, a plating-resist layer having a pattern

reverse to a specified circuit pattern is formed by using a dry film resist, and a conductive 15 layer having a specified circuit pattern is formed by electrolytic copper plating, in the portion

of the base layer where the plating-resist layer is not formed. Thereafter, the plating-resist

layer is removed by chemical etching, and then the thin Cr film and the thin Cu film on which

the plating-resist layer is formed are removed by chemical etching. The conductive layer has

a thickness of 20 μm, and is formed to have a pattern defined by four wired circuits, the wired 20 circuits have a width of 20 μm respectively and are spaced in parallel at an interval of 30 μm.

Next, by electroless nickel plating, a hard and thin Ni film having a thickness of 0.1 μm

is formed on the surface of the conductive layer and on the surface of the stainless steel foil. Thereafter, a liquid solution of polyamic acid resin is applied to the thin Ni film and the base

layer, and then heated at 130℃, thereby forming a coating of polyamic acid resin, and 25 subsequently, the coating is exposed (405 nm, 1500 mJ/cm

2) through a photomask. The

exposed portion is heated to 180℃, and then developed by using an alkaline developer,

thereby causing the coating to form a pattern, so that the coating can be used to cover the

conductive layer. Subsequently, the patterned polyamic acid resin coating is heated at 350℃

to be cured (imidized), thereby forming a cover layer of polyimide having a thickness of 3 30 μm on the conductive layer. During formation of the cover layer, the portion of the

conductive layer to be formed as pad portions of an external connection terminal and a

magnetic-head connection terminal, should be avoided to be covered by the cover layer.

Thereafter, the thin Ni film formed on the stainless steel foil and the thin Ni film formed

in the portion of the conductive layer to be formed as pad portions of an external connection 35 terminal and a magnetic-head connection terminal, are peeled off. Thereafter, the

corresponding portion to be formed as pad portions is sequentially subjected to electrolytic

nickel plating and electrolytic gold plating, thereby forming a Ni coating layer having a

thickness of 2 μm and an Au plating layer having a thickness of 1 μm, so as to generate pad

portions. Then, the lead wires used in electrolytic nickel plating and electrolytic gold plating 40 is removed by chemical etching. Thereafter, the stainless steel foil is cut to a specified shape

by chemical etching. In this cutting process, in the meantime, the stainless steel foil is formed

with a rectangular opening at the separated portion corresponding to the pad portions. Then,

after being washed and dried, a suspension board with circuit is obtained. 45


14

The external connection terminal of the suspension board with circuit of Example 1

corresponds to the embodiment shown in FIGS. 2 to 4.

Example 2

A suspension board with circuit is produced by the same operations in Example 1,

except that, when cutting the stainless steel foil by chemical etching, an opening is made to 5 the stainless steel foil, so that a single large rectangular opening containing all of the pad

portions is formed, instead of separately forming openings in the portion of the stainless steel

foil corresponding to the pad portions.


corresponds to the embodiment shown in FIGS. 9 and 10. 10 Example 3

A liquid solution of polyamic acid resin is applied to a stainless steel foil having a

thickness of 25 μm, then heated at 130℃, thereby forming a coating of polyamic acid resin. Next, the coating is exposed (405 nm, 1500 mJ/cm


portion is heated to 180℃, and then developed by using an alkaline developer, thereby 15 causing the coating to form a pattern by means of a negative image. In the process of forming

the pattern, the coating is not formed at the portion on which pad portions of the external

connection terminal is to be formed. Subsequently, the patterned polyamic acid resin coating

is heated at 350℃ to be cured (imidized), thereby forming a base layer of polyamic acid resin

having a specified pattern and a thickness of 15 μm. 20 Then, through a sputter deposition process, a thin Cr film having a thickness of 300Å


of the base layer and the stainless steel foil. Thereafter, a plating-resist layer having a pattern

reverse to a specified circuit pattern is formed by using a dry film resist. Then, in the portion

of the base layer where the plating-resist layer is not formed, and in the portion of the 25 stainless steel foil exposed through the base layer in form of a specified circuit pattern (or in

the portion where pad portions are to be formed), a conductive layer is formed by electrolytic

copper plating. Thereafter, the plating-resist layer is removed by chemical etching, and then

the thin Cr film and the thin Cu film on which the plating-resist layer is formed are removed

by chemical etching. The conductive layer has a thickness of 20 μm, and is formed to have a 30 pattern defined by four wired circuits, the wired circuits have a width of 20 μm respectively

and are spaced in parallel at an interval of 30 μm.


is formed on the surface of the conductive layer and on the surface of the stainless steel foil. Thereafter, a liquid solution of polyamic acid resin is applied to the thin Ni film and the base 35 layer, and then heated at 130℃, thereby forming a coating of polyamic acid resin. Subsequently, the coating is exposed (405 nm, 1500 mJ/cm2) through a photomask. The


thereby causing the coating to form a pattern, so that the coating can be used to cover the

conductive layer. Subsequently, the patterned polyamic acid resin coating is heated at 350℃ 40 to be cured (imidized), thereby forming a cover layer of polyimide having a thickness of 3

μm on the conductive layer. During formation of the cover layer, the portion of the


magnetic-head connection terminal, should be avoided to be covered by the cover layer. 45


15

Thereafter, the thin Ni film formed on the stainless steel foil and the thin Ni film formed

in the portion of the conductive layer to be formed as pad portions of an external connection

terminal and a magnetic-head connection terminal, are peeled off. Thereafter, said portion to

be formed as pad portions is sequentially subjected to electrolytic nickel plating and

electrolytic gold plating, thereby forming a Ni coating layer having a thickness of 2 μm and 5 an Au plating layer having a thickness of 5 μm, so as to generate pad portions. Then, the lead

wires used in electrolytic nickel plating and electrolytic gold plating is removed by chemical

etching. Thereafter, the stainless steel foil is cut to a specified shape by chemical etching. In

this cutting process, in the meantime, the stainless steel foil is formed with a rectangular

opening at the separated portion corresponding to the pad portions. Then, after being washed 10 and dried, a suspension board with circuit is obtained.


corresponds to the embodiment shown in FIGS. 11 to 13.

Example 4

A liquid solution of polyamic acid resin is applied to a stainless steel foil having a 15 thickness of 25 μm, then heated at 130℃, thereby forming a coating of polyamic acid resin. Next, the coating is exposed (405 nm, 1500mJ/cm


portion is heated to 180℃, and then developed by using an alkaline developer, thereby

causing the coating to form a pattern by means of a negative image. Subsequently, the

patterned polyamic acid resin coating is heated at 350℃ to be cured (imidized), thereby 20 forming a base layer of polyamic acid resin having a specified pattern and a thickness of 10

μm.

Then, through a sputter deposition process, a thin Cr film having a thickness of 300Å


of the base layer and the stainless steel foil. Thereafter, a plating-resist layer having a pattern 25 reverse to a specified circuit pattern is formed by using a dry film resist. Then, a conductive

layer having a specified circuit pattern is formed by electrolytic copper plating, in the portion

of the base layer where the plating-resist layer is not formed. Thereafter, the plating-resist

layer is removed by chemical etching, and then the thin Cr film and the thin Cu film on which

the plating-resist layer is formed are removed by chemical etching. The conductive layer has 30 a thickness of 10 μm, and is formed to have a pattern defined by four wired circuits, the wired

circuits have a width of 100 μm respectively and are spaced in parallel at an interval of 500

μm.


is formed on the surface of the conductive layer and on the surface of the stainless steel foil. 35 Thereafter, a liquid solution of polyamic acid resin is applied to the thin Ni film and the base

layer, and then heated at 130℃, thereby forming a coating of polyamic acid resin. Subsequently, the coating is exposed (405 nm, 1500 mJ/cm

2) through a photomask. The


thereby causing the coating to form a pattern, so that the coating can be used to cover the 40 conductive layer. Subsequently, the patterned polyamic acid resin coating is heated at 350℃

to be cured (imidized), thereby forming a cover layer of polyimide having a thickness of 3

μm on the conductive layer. During formation of the cover layer, the portion of the


16


magnetic-head connection terminal, should be avoided to be covered by the cover layer. The

cover layer is formed to have a single large rectangular opening containing all the pad

portions, particularly in the portion of the cover layer to be formed as pad portions of the

external connection terminal. 5 Next, the stainless steel foil is cut to a specified shape by chemical etching. In this

cutting process, the stainless steel foil is cut at the portions thereof corresponding to the pad

portions into a rectangular shape containing all the pad portions, thereby forming an opening. Thereafter, the thin Ni film formed on the stainless steel foil and the thin Ni film formed in

the portion of the conductive layer to be formed as pad portions of an external connection 10 terminal and a magnetic-head connection terminal, are peeled off. Thereafter, by laser

processing, according to the opening, an opening is made to the base layer exposed through

the opening formed by cutting the stainless steel foil. Thereafter, by chemical etching, the thin

Cr film and the thin Cu film exposed through the opening of the base layer are peeled off,

thereby exposing the back surface of the conductive layer, said back surface is opposite the 15 front surface of the conductive layer on which the pad portions are to be formed. Then, the

front surface of the conductive layer is sequentially subjected to electrolytic nickel plating

and electrolytic gold plating, thereby forming a Ni coating layer having a thickness of 2 μm

and an Au plating layer having a thickness of 1 μm, so as to generate pad portions. Meanwhile, the same plating layer is formed on the both lateral surfaces and the back surface 20 of the exposed conductive layer. Finally, the lead wires used in electrolytic nickel plating and

electrolytic gold plating are removed by chemical etching, thereby obtaining the suspension

board with circuit.


corresponds to the embodiment shown in FIGS. 16 to 18. 25 Comparative Example 1

A suspension board with circuit is produced by the same operations in Example 1,

except that, when cutting the stainless steel foil into a specified form by chemical etching, no

opening is formed at the portion of the stainless steel foil corresponding to the pad portions.

The external connection terminal of the suspension board with circuit of Comparative 30 Example 1 corresponds to the embodiment shown in FIG. 21.

Assessment

1) generating a board to be bonded:

A board to be bonded as shown in FIG. 22 is generated. The board to be bonded as

shown in FIG. 22 may be generated as follows. A base layer 42 formed of polyimide and 35 having a thickness of 10 μm is laminated on a suspension board 41 formed from a stainless

steel foil having a thickness of 25 μm. Then, a conductive layer 43 made of Cu and having a

thickness of 10 μm is formed in form of 4 wired circuits on the base layer 42; moreover, a Ni

plating layer 44 having a thickness of 2 μm and an Au plating layer 45 having a thickness of

5 μm are sequentially formed at the end portion of each of the wired circuits, thereby forming 40 4 connection terminals 46.


17

2) bonding between the suspension board with circuit and the board to be bonded:

For each suspension board with circuit in Examples 1 to 4 and Comparative Example 1,

the Au plating surfaces of the 4 pad portions of the external connecting terminal are aligned

and fixed to 4 connection terminals of the board to be bonded, and then, by using a bonding

tool of a ultrasonic-vibration bonding device, the two boards are bonded to each other, in 5 which said ultrasonic vibration bonding device abuts against the pad portions from the rear

side of the suspension board with circuit. Bonding conditions are as follows.

An ultrasonic-vibration bonding device: A 260-type available from ANZA Corp

Temperature: Room temperature

Ultrasonic vibration output: 3.0 W 10 Load: 200gf (1.96N)

Time: 400 ms.

(3) Peeling Test:

The bonding characteristics between terminals are assessed by a 90-degree peeling test. In the 90-degree peeling test, the board to be bonded is fixed to a horizontal fixing board by 15 an adhesive agent, while the suspension board with circuit is in a state of being bent 90-

degrees upwardly, then the suspension board with circuit is clamped at the end opposite the

bonding side and stretched as shown in FIG. 23. Measuring conditions are as follows. Results

are given in the following Table 1. In Table 1, "Breakage Mode A" represents breakage of a

board, which indicates good bonding characteristics; whereas "Breakage Mode B" represents 20 peel-off of pad portions, which indicates poor bonding characteristics. "Bonding Strength"

represents strength of each terminal.

A tensile-strength testing machine: A 1011 type / 1321DW type available from AIKOH

ENGINEERING,

Peeling rate: 10 mm/min 25

Table 1

Sample No. (N)

Example 1 Example 2 Example 3 Example 4 Comparative Example 1

Bonding

Strength (mN)

Breakage Mode

Bonding

Strength (mN)

Breakage Mode

Bonding

Strength (mN)

Breakage Mode

Bonding

Strength (mN)

Breakage Mode

Bonding

Strength (mN)

Breakage Mode

1 1,176 A 1,196 A 1,136 A 1,270 A 138 B

2 1,098 A 744 B 1,274 A 1,255 A 118 B

3 1,156 A 1,136 A 1,176 A 1,268 A 196 B

4 764 B 1,176 A 1,216 A 1,281 A 176 B

Mean Value

1,048.5 1,063.0 1,200.5 1,268.5 157.0


18

As can be clearly seen from Table 1, compared with the suspension board with circuit of

Comparative Example 1, each suspension board with circuit in Examples 1 to 4 has a high

bonding strength indicating excellent bonding characteristics.

Although illustrative embodiments of the present invention are provided in the above

description, these illustrative embodiments are merely for illustration, not for limiting. A 5 person skilled in the art will understand that, variations and modifications of the present

invention are encompassed by the claims as appended hereto.


1

ACCOMPANYING DRAWINGS


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Translator’s Declaration

I, Yang Huan, hereby declare:

(1) I am a translator fluent in the Chinese and English languages. My qualifications are as follows:

6 years of experience as a translator of patents from Chinese to English

(2) I have translated the following document from Chinese into English:

Chinese Application No. CN 1297224A

Published on May 30, 2001

(3) The attached English translation is, to the best of my knowledge and belief, a true, full, and

accurate translation of Chinese Application No. CN 1297224A.

(4) I understand that willful false statements and the like are punishment by fine or imprisonment,

or both (18 U.S.C. 1001). I declare under penalty of perjury that all statements made herein of my own

knowledge are true and all statements made on information and belief are believed to be true.

Date: ____2017.4.12__________________ __________________________

Yang Huan

TRANSLATOR CERTIFICATION


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