KR20220011277A - Flexible printed circuit board and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a flexible printed circuit board (PCB) and a manufacturing method thereof. The flexible PCB of the present invention comprises: a base film layer; a conductive pattern layer formed on the top of the base film layer; an upper film layer formed on the top of the conductive pattern layer; and a protective layer formed on the bottom of the base film layer, wherein at least one end portion of the flexible PCB has a protrusion portion formed by bending the base film layer and the conductive pattern layer. In addition, the upper film layer is removed from at least a part of the protrusion portion and a first metal layer is formed on the top of the bent conductive pattern layer. Moreover, an inner groove is formed on the bottom of the protrusion portion and a reinforcing member for reinforcing the strength of the protrusion portion is disposed in the inner groove. According to the present invention, the protrusion portion enhances contact performance between the same and a contact pad of the device to be tested.

Description

Flexible printed circuit board and manufacturing method thereof

The present invention relates to a flexible printed circuit board and a method of manufacturing the same, and more particularly, to a flexible printed circuit board that improves the contact performance between the protrusion and the contact pad of the device under test by protruding a part of the flexible printed circuit board as a whole to form the protrusion. It relates to a printed circuit board and a method for manufacturing the same.

A liquid crystal display panel (hereinafter referred to as an LCD panel), a plasma display panel (hereinafter referred to as a PDP panel), an active matrix organic A plurality of contact pads for applying an electrical signal may be provided at an edge portion of an image display panel such as a light emitting diode display panel (hereinafter referred to as an AMOLED panel).

An object to be inspected, such as an image display panel, may be inspected using a probe unit having a plurality of probes provided to be in contact with contact pads.

A general probe unit may include a base block and a plurality of probes connected to a circuit board disposed on a lower surface of the base block and configured to be in contact with contact pads.

Also, a separate mounting block for mounting the probes to the base block may be used. However, it is a very difficult task to precisely arrange and fix the probes to correspond to the contact pads, and it is also very difficult to replace the damaged probes when the probes are damaged during the inspection process.

In order to solve this problem, an inspection apparatus using a flexible printed circuit board has recently been developed.

The flexible printed circuit board is provided with a plate-shaped contact part on one side of the circuit board main body, and a test signal is generated by contact between the plate-shaped contact part and the contact pad.

At this time, the conductive pattern layer formed of copper (Cu) constituting the contact portion is exposed to the outside for contact with the contact pad, and in order to prevent corrosion of the conductive pattern layer exposed to the outside, it is plated with gold (Au). A plating layer was formed. However, since the thickness of the plating layer formed of gold is thin, the plating layer is peeled off during a number of tests, and there is a problem in that corrosion occurs or foreign substances are deposited on the conductive pattern layer.

In addition, as the contact part of the flexible printed circuit board and the contact pad of the device under test come into contact with each other, there is a problem that the contact is not made well. of bumps were formed. Although the contact portion having this structure could maintain contact stability while making contact with the contact pad, there was a problem in that the bump was detached from the contact portion when a lot of testing was performed, causing damage to the contact pad.

Domestic Patent Publication No. 10-2012-0032078 (published on April 5, 2012)

The present invention has been devised to solve the problems described above, and an object of the present invention is to form a protrusion by protruding a part of a flexible printed circuit board as a whole, thereby improving the contact performance between the protrusion and the contact pad of the device under test. An object of the present invention is to provide a flexible printed circuit board and a method for manufacturing the same.

In order to achieve the above object, the flexible printed circuit board according to the present invention includes a base film layer; a conductive pattern layer formed above the base film layer; an upper film layer formed above the conductive pattern layer; and a protective layer formed under the base film layer, wherein at least one end of the flexible circuit board has a protrusion formed by bending the base film layer and the conductive pattern layer; At least a portion of the protrusion, the upper film layer is removed, a first metal layer is formed on the upper side of the curved conductive pattern layer, an inner groove is formed on the lower side of the protrusion, and the rigidity of the protrusion is reinforced in the inner groove It is characterized in that the reinforcing member is provided.

In addition, the method for manufacturing a flexible printed circuit board according to the present invention includes a base film layer, a conductive pattern layer formed on an upper side of the base film layer, an upper film layer formed on an upper side of the conductive pattern layer, and a protection formed below the base film layer In the method of manufacturing a flexible circuit board including a layer, a portion of the upper film layer formed on the upper side of the conductive pattern layer is removed, and a first metal layer is formed on the upper side of the conductive pattern layer from which the upper film layer is removed. forming a first metal layer; a protrusion forming step of forming a protrusion by bending the base layer, the conductive pattern layer, and the first metal layer positioned at a portion where the upper film layer is removed; and a reinforcing member forming step of forming a reinforcing member in the inner groove formed on the lower side of the protrusion.

The flexible printed circuit board and the method for manufacturing the same according to the present invention have the effect of improving the contact performance between the protrusion and the contact pad of the device under test by protruding a part of the flexible printed circuit board as a whole to form the protrusion.

In addition, by providing the first metal layer and the second metal layer on the protrusion to increase the rigidity of the protrusion, there is an effect that can extend the life of the protrusion.

In addition, according to the present invention, since the reinforcing member having elastic restoring force is provided in the inner groove of the protrusion, there is an effect of increasing the rigidity of the protrusion and maximally preventing the deformation of the protrusion.

In addition, according to the present invention, there is an effect that can prevent the reinforcing member from being separated from the inner groove of the protrusion by the protective layer.

1 is a diagram schematically showing the structure of a flexible printed circuit board according to an embodiment of the present invention.
2 is a diagram schematically illustrating a state in which a flexible printed circuit board and a device under test are in contact according to an embodiment of the present invention.
FIG. 3 is an enlarged view of part A of FIG. 2 .
4 is a perspective view schematically illustrating a part of a protrusion according to an embodiment of the present invention.
5 is a view illustrating a state in which the protrusion and the contact pad are in contact according to an embodiment of the present invention.
6 is a view showing a process of forming a protrusion according to an embodiment of the present invention.
7 is a view schematically illustrating a manufacturing process of a flexible printed circuit board according to an embodiment of the present invention.
8 is a view schematically showing a modified example of the protrusion according to an embodiment of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. At this time, it should be noted that in the accompanying drawings, the same components are denoted by the same reference numerals as much as possible. In addition, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted.

Hereinafter, a flexible printed circuit board according to an embodiment of the present invention will be described with reference to the accompanying drawings 1 to 6 .

1 is a diagram schematically showing the structure of a flexible printed circuit board according to an embodiment of the present invention, and FIG. 2 is a schematic view showing a state in which the flexible printed circuit board according to an embodiment of the present invention and a device under test are in contact 3 is an enlarged view of part A of FIG. 2 .

4 is a perspective view schematically showing a part of the protrusion according to an embodiment of the present invention, and FIG. 5 is a view showing a state in which the protrusion and the contact pad are in contact according to an embodiment of the present invention.

1 to 5 , the flexible printed circuit board 100 according to an embodiment of the present invention includes a base film layer 111 and a conductive pattern layer 112 formed on the upper side of the base film layer 111 . , an upper film layer 113 formed on an upper side of the conductive pattern layer 112 and a protective layer 125 formed on a lower side of the base film layer 111 , and at least one end of the flexible circuit board has a base film The protrusion 120 formed by bending the layer 111 and the conductive pattern layer 112 is formed, and at least a portion of the protrusion 120 has the upper film layer 113 removed and the curved conductive pattern layer 112 . A first metal layer 121 is formed thereon, an inner groove 120a is formed on the lower side of the protrusion 120 , and a reinforcing member 124 for reinforcing the rigidity of the protrusion 120 is provided in the inner groove 120a. can be

Referring again to FIGS. 1 to 5 , a flexible printed circuit board according to an embodiment of the present invention will be described in detail.

The base film layer 111 according to an embodiment of the present invention may be made of, for example, a flexible insulating material such as polyimide.

A conductive pattern layer 112 may be formed on an upper side of the base film layer 111 , and the conductive pattern layer 112 may be made of a conductive material such as copper (Cu).

A plurality of signal wires 112a electrically connected to the contact pad 11 of the device under test 10 may be provided on the conductive pattern layer 112 .

The upper film layer 113 may be formed on the upper side of the conductive pattern layer 112 , and may be made of a flexible insulating material such as polyimide, like the base film layer 111 .

Meanwhile, a pad contact area PA (refer to FIG. 7 ) from which the upper film layer 113 is removed may be provided at one end of the flexible printed circuit board 100 .

In more detail, the upper film layer 113 partially covers the conductive pattern layer 112 , but on the upper side of the remaining conductive pattern layer 112 to expose the conductive pattern layer 112 on the pad contact area PA side. can be formed in Here, the pad contact area PA may be an area in which a protrusion to be described later is formed.

4 and 5 , the protrusion 120 according to an embodiment of the present invention may be formed by bending the base film layer 111 and the conductive pattern layer 112 positioned in the pad contact area PA. It may come into contact with the contact pad 11 of the device under test 10 and serve as a conventional contact unit to generate a test signal.

For example, the contact portion of the conventional flexible printed circuit board is formed to have a plate structure, and as it comes into contact with the plate structure contact pad face-to-face, there is a problem in that the contact is not made well, A spherical bump was formed on the upper surface using the MEMS method. Although the contact portion having such a structure could maintain contact stability while making contact with the contact pad, there was a problem in that the bump was detached from the contact portion when a lot of testing was performed, causing damage to the contact panel.

The protrusion 120 according to an embodiment of the present invention is formed by bending the first metal layer 121 and the second metal layer 122, the base film layer 111, and the conductive pattern layer 112 to be described later. As the contact pad 11 of the device under test 10 is brought into contact with the protrusion 120 , it replaces the conventional bump role and maintains contact stability while solving the problem of damaging the contact panel from which the conventional bump is detached. can be

According to an embodiment of the present invention, the first metal layer 121 may be formed on the curved conductive pattern layer 112 on at least a portion of the protrusion 120 .

The first metal layer 121 according to an embodiment of the present invention may be formed of an alloy plate having a predetermined thickness, and serves to reinforce the rigidity of the protrusion 120 .

In this embodiment, it is suggested that the first metal layer 121 is formed of a BNT alloy plate having high rigidity and thermal conductivity among various materials.

The BNT alloy plate is an alloy plate formed by melting beryllium, nickel, and titanium materials, and is commonly referred to as NiBe2-Alloy 360.

According to an embodiment of the present invention, by attaching the first metal layer 121 formed of a BNT alloy plate with high rigidity to the upper side of the conductive pattern layer 112 located in the pad contact area PA of the printed circuit board, the protrusion The rigidity of (120) is increased. Accordingly, even when the protrusion 120 and the contact pad 11 come into contact with each other a plurality of times, deformation of the protrusion 120 is prevented, and thus the lifespan of the protrusion 120 can be extended.

More specifically, when the conductive pattern layer 112 of the protrusion 120 comes into contact with the contact pad 11 during the test process, the conductive pattern layer 112 undergoes stretching deformation due to heat and pressure applied to the conductive pattern layer 112 . can be received

In this case, the first metal layer 121 is attached to the pad contact area PA of the conductive pattern layer 112 that is subjected to such stretching deformation, and serves to prevent stretching deformation.

For example, when the first metal layer 121 is made of a BNT alloy plate, since the first metal layer 121 has high rigidity and thermal conductivity, the conductive pattern layer 112 has a relatively small strain with respect to heat and pressure. Therefore, the conductive pattern layer 112 can physically prevent stretching deformation and maintain its shape. In addition, since the first metal layer 121 has high thermal conductivity, heat may be evenly distributed throughout the first metal layer 121 . Therefore, even when high heat is partially applied to a specific location, partial deformation can be prevented by dispersing it throughout.

It should be noted that although the first metal layer 121 according to an embodiment of the present invention may be attached to the pad contact area PA of the conductive pattern layer 112 by ACF bonding, this is not suggested.

For example, ACF bonding uses an anisotropic conductive film to enable electrical conduction up and down (the conductive pattern layer 112 and the first metal layer 121) and to insulate the left and right sides. it will be a way Of course, since the first metal layer 121 may be attached to the pad contact area PA of the conductive pattern layer 112 by a method using a metal adhesive, the method of attaching the first metal layer 121 is not necessarily limited. .

According to an embodiment of the present invention, the second metal layer 122 may be formed below the bent base film layer 111 while forming the protrusion 120 .

The second metal layer 122 may be formed of a BNT alloy plate having high rigidity and thermal conductivity, which is the same material as the first metal layer 121 , and may be attached to the lower surface of the base film layer 111 by ACF bonding.

The second metal layer 122 serves to prevent deformation of the protrusion 120 by increasing the rigidity of the protrusion 120 together with the first metal layer 121 .

Meanwhile, the first metal layer 121 prevents stretching deformation of the conductive pattern layer 112 , while the second metal layer 122 prevents stretching deformation of the base film layer 111 . Since the action of the second metal layer 122 is the same as that of the first metal layer 121 , a detailed description thereof will be omitted.

Meanwhile, the protrusion 120 according to an embodiment of the present invention may be formed through a press mold method.

6 is a view showing a process of forming a protrusion according to an embodiment of the present invention. Here, (a) of FIG. 6 is a view showing a state before the protrusion is formed in the pad contact area of the flexible printed circuit board, and FIG. 6 (b) is the protrusion in the pad contact area PA of the flexible printed circuit board. It is a diagram showing the formed state.

Referring to FIG. 6 , the protrusion 120 may be formed in the pad contact area PA through a press device, and as an example, a shape corresponding to the protrusion 120 as shown in FIG. 6( a ). After positioning the pad contact area PA of the printed circuit board in the press block 210 having the groove 211 of As shown in FIG. 6B , the protrusion 120 is formed in the pad contact area PA of the flexible printed circuit board.

Although the method of forming the protrusion 120 according to an embodiment of the present invention is exemplified as using a press mold, it should be noted that the protrusion 120 may be formed by various methods.

On the other hand, an inner groove is formed in the lower portion of the protrusion 120 according to an embodiment of the present invention, and when the contact pad 11 and the protrusion 120 are in contact, the rigidity of the protrusion 120 is reinforced by elastic restoring force. A reinforcing member 124 may be provided.

It should be noted that although it is suggested that liquid epoxy is used as the material of the reinforcing member 124 according to an embodiment of the present invention, the present invention is not limited thereto.

The reinforcing member 124 may be formed by applying liquid epoxy to the inner groove 120a using an application device such as a syringe pump, and then curing it.

On the other hand, depending on the structure of the protrusion 120 and the type of the device to be tested, the reinforcing member 124 may be used by disposing a member such as a spring in the inner groove.

As a result, as the reinforcing member 124 is provided in the inner groove 120a of the protrusion 120, when the protrusion 120 and the contact pad 11 come into contact, the rigidity of the protrusion 120 can be secured as much as possible. , it is possible to prevent the protrusion 120 from being deformed as much as possible in the case of multiple tests.

In addition, the protective layer 125 according to an embodiment of the present invention is attached to the lower side of the second metal layer 122 to prevent the reinforcing member 124 from being separated from the inner groove 120a to the outside.

The protective layer 125 may be made of an insulating material, and although it is suggested that the protective layer 125 is formed of a coverlay film in this embodiment, it should be noted that the present invention is not limited thereto.

For example, when the protrusion 120 and the contact pad 11 are in contact, the reinforcing member 124 provided in the inner groove 120a of the protrusion 120 is separated from the wall surface of the inner groove 120a by impact. It can be separated from the inner groove (120a).

At this time, the protective layer 125 blocks the open portion of the inner groove 120a, so that even if the reinforcing member 124 is separated from the wall surface of the inner groove 120a, it is separated from the inner groove 120a and is separated from the outside. make it possible to prevent

7 is a diagram schematically illustrating a manufacturing process of a flexible printed circuit board according to an embodiment of the present invention.

A method of manufacturing the flexible printed circuit board 100 according to an embodiment of the present invention will be described with reference to FIG. 7 .

The method of manufacturing a flexible printed circuit board according to an embodiment of the present invention may include forming a first metal layer, forming a second metal layer, forming a protrusion, forming a reinforcing member, and forming a protective cover.

First, referring to FIGS. 7A and 7B , in the step of forming the first metal layer, the process of forming the first metal layer 121 on the pad contact area PA formed on the conductive pattern layer 112 is performed. is carried out

In this case, the first metal layer 121 is attached to the upper side of the conductive pattern layer 112 of the pad contact area PA using the ACF bonding method.

Next, referring to FIG. 7C , in the step of forming the second metal layer, a process of forming the second metal layer 122 under the base film layer 111 is performed.

In this case, in the second metal layer 122 forming step, the second metal layer 122 is formed on the lower side of the base film layer 111 using the ACF bonding method in the same manner as in the first metal layer 121 forming step. A metal layer 122 is attached.

In this case, a BNT alloy plate formed by melting beryllium, nickel, and titanium materials is used for the first metal layer 121 and the second metal layer 122 , respectively.

Next, referring to FIG. 7D , in the step of forming the protrusion, the protrusion 120 is formed by bending the second metal layer, the base layer, the conductive pattern layer, and the first gold leaf layer positioned on the pad contact area PA. process is carried out.

In this case, the step of forming the protrusion may be performed by a press mold method.

To explain this process, the pad contact area PA of the flexible printed circuit board is positioned on the press block 210 having the groove 211 having a shape corresponding to the protrusion 120 , and then the pad is pressed with the press member 220 . The lower portion of the contact area PA is compressed to be inserted into the groove 211 . In this process, the protrusion 120 is formed to fit into the groove 211 while the pad contact area PA is in close contact with the inner surface of the groove 211 by compression of the press member 220 .

Next, referring to FIG. 7E , in the forming step of the reinforcing member, a process of forming the reinforcing member 124 in the inner groove 120a formed on the lower side of the protrusion 120 is performed.

At this time, the material of the reinforcing member 124 may be liquid epoxy, and the reinforcing member 124 may be formed by applying liquid epoxy to the inner groove 120a using a syringe pump (not shown). .

Next, referring to FIG. 7F , in the step of attaching the protective layer 125 , a process of attaching the protective layer 125 to the lower side of the second metal layer 122 is performed.

In this case, the protective layer 125 is attached to extend to the lower surface of the base film layer 111 of the main body 110 .

Through the above-described process, the flexible printed circuit board according to an embodiment of the present invention can be manufactured.

8 is a view schematically showing a modified example of the protrusion according to an embodiment of the present invention, and it is suggested that the upper film layer 113 is formed on the upper side of the conductive pattern layer 112 except for the first metal layer 121 . do.

In this case, in the process of forming the first metal layer 121 on the upper side of the curved conductive pattern layer 112 , it is necessary to cut the upper film layer 113 as much as the area where the first metal layer 121 is formed.

The action of the protrusion of the modified example according to the embodiment of the present invention is the same as the action of the protrusion according to the embodiment of the present invention described above, and thus a detailed description thereof will be omitted.

Meanwhile, in the present invention, the structure of the protrusion 120 has been described as an example applied to a flexible printed circuit board. It can also be applied to the same product.

As described above, in the flexible printed circuit board and the manufacturing method thereof according to the present invention, the contact performance between the protrusion and the contact pad of the device under test can be improved by forming the protrusion by protruding a part of the flexible printed circuit board as a whole. have.

In addition, by providing the first metal layer and the second metal layer to the protrusion to increase the rigidity of the protrusion, the lifespan of the protrusion may be extended.

In addition, according to the present invention, since the reinforcing member having elastic restoring force is provided in the inner groove of the protrusion, it is possible to increase the rigidity of the protrusion to prevent deformation of the protrusion as much as possible.

In addition, according to the present invention, it is possible to prevent the reinforcing member from being separated from the inner groove of the protrusion by the protective layer.

Although the present invention has been described with reference to embodiments, it is not necessarily limited thereto, and modifications and variations are possible within the scope of the technical spirit of the present invention.

10: device under test 11: contact pad
100: flexible circuit board for inspection 111: base film layer
112: conductive pattern layer 112a: signal wiring
113: upper film layer 120: protrusion
121: first metal layer 122: second metal layer
120a: inner groove 124: reinforcing member
125: protective layer

Claims (12)

base film layer;
a conductive pattern layer formed above the base film layer;
an upper film layer formed above the conductive pattern layer; and
In the flexible circuit board comprising a; a protective layer formed below the base film layer,
A protrusion formed by bending the base film layer and the conductive pattern layer is formed on at least one end of the flexible circuit board,
At least a portion of the protrusion, the upper film layer is removed and a first metal layer is formed on the curved conductive pattern layer,
An inner groove is formed on a lower side of the protrusion, and a reinforcing member for reinforcing the rigidity of the protrusion is provided in the inner groove. According to claim 1,
A flexible printed circuit board having a second metal layer formed below the bent base film layer. 3. The method of claim 2,
Each of the first and second metal layers is a flexible printed circuit board, characterized in that it is formed of a BNT alloy plate formed by melting beryllium, nickel, and titanium material. 3. The method of claim 2,
The first metal layer is attached to the upper side of the conductive pattern layer by ACF (Anisotropic Conductive Film) bonding, and the second metal layer is attached to the lower side of the base film layer by the ACF (Anisotropic Conductive Film) bonding. circuit board. According to claim 1,
Liquid epoxy is used as the material of the reinforcing member,
The reinforcing member is a flexible printed circuit board formed by applying the liquid epoxy to the inner groove through a syringe pump. According to claim 1,
The reinforcing member is a flexible printed circuit board that is prevented from being separated from the inner groove by the protective layer. In the manufacturing method of a flexible circuit board comprising a base film layer, a conductive pattern layer formed above the base film layer, an upper film layer formed above the conductive pattern layer, and a protective layer formed below the base film layer,
a first metal layer forming step of removing a portion of the upper film layer formed on the upper side of the conductive pattern layer, and forming a first metal layer on the upper side of the conductive pattern layer from which the upper film layer is removed;
a protrusion forming step of forming a protrusion by bending the base layer, the conductive pattern layer, and the first metal layer positioned at a portion where the upper film layer is removed;
and a reinforcing member forming step of forming a reinforcing member in the inner groove formed on the lower side of the protrusion. 8. The method of claim 7,
After the first metal layer forming step,
The method of manufacturing a flexible printed circuit board further comprising a second metal layer forming step of forming a second metal layer under the base film layer. 8. The method of claim 7,
Each of the first and second metal layers is a method of manufacturing a flexible printed circuit board formed of a BNT alloy plate formed by melting beryllium, nickel, and titanium material. 9. The method of claim 8,
The first metal layer is attached to the upper side of the conductive pattern layer by ACF (Anisotropic Conductive Film) bonding, and the second metal layer is attached to the lower side of the base film layer by the ACF (Anisotropic Conductive Film) bonding. A method for manufacturing a circuit board. 8. The method of claim 7,
In the forming of the reinforcing member, a method of manufacturing a flexible printed circuit board by applying a liquid epoxy to the inner space using a syringe pump to form the reinforcing member. 8. The method of claim 7,
After the reinforcing member forming step,
The method of manufacturing a flexible printed circuit board further comprising a protective layer attaching step of attaching a protective layer to the lower side of the second metal layer in order to prevent the reinforcing member from being separated from the inner groove.

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