WO2018034525A1 - Flexible circuit board - Google Patents

Abstract

A flexible circuit board is provided. The flexible circuit board comprises: a base substrate having a test area defined on one side thereof; one or more first connection pads respectively and electrically connected to first wiring patterns formed on the one side of the base substrate; one or more second connection pads disposed on the one side of the base substrate and respectively and electrically connected to second wiring patterns formed on the other side of the base substrate, which is a side opposite to the one side of the base substrate; and test patterns extending onto the test area from the second connection pad(s).

Description

Flexible circuit board

The present invention relates to a flexible circuit board.

Recently, according to the trend of miniaturization in electronic devices, chip on film (COF) packaging technology using a flexible circuit board is being used. Flexible circuit boards and COF package technology using the same are used in flat panel displays (FPDs), such as liquid crystal displays (LCDs), organic light emitting diode (OLED) display devices, and the like. do.

A conductive wiring pattern for transmitting an electrical signal may be formed on the flexible circuit board. In order to determine whether the conductive wiring is open or shorted, a separate test pad or a probe in electrical contact with a via land surrounding a via may be used on the substrate.

However, in the case of forming a separate test pad, there is a side that requires extra space on the substrate, which does not meet the miniaturization requirements of the electronic device, and when the via land is directly inspected by a probe, foreign matters caused by contact and There is a problem that a terminal defect occurs.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a flexible circuit board capable of inspecting whether a short circuit is opened or not, without causing a terminal defect in a via land.

Technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

A flexible circuit board according to an embodiment of the present invention for achieving the above technical problem, is electrically connected to a base substrate, a test area is defined on one surface, a first wiring pattern formed on the one surface of the base substrate, respectively At least one or more first connection pads disposed on the one surface of the base substrate, each of the at least one second connection pads electrically connected to a second wiring pattern formed on the other surface of the base substrate on the other surface And a test pattern extending from the second connection pad onto the test area.

In some embodiments of the present disclosure, the test pattern includes a first test pattern extending from the first connection pad onto the test region and a second test pattern extending from the second connection pad onto the test region. can do.

In some embodiments of the present disclosure, the first test pattern and the second test pattern may be disposed to intersect in the test area.

In some embodiments of the present disclosure, the test region may include a first test region in which a first test pattern is disposed and a second test region in which the second test pattern is disposed.

In some embodiments of the present disclosure, the first test area or the second test area may be disposed between the first connection pad and the second connection pad.

In some embodiments of the present disclosure, the first test area or the second test area may be disposed between an end of the flexible circuit board and the first connection pad or the second connection pad.

In some embodiments of the present invention, the test pattern may be 45 degrees to 135 degrees with respect to the probe scanning progress direction.

In some embodiments of the present disclosure, the second connection pad may be electrically connected to the second wiring pattern and may vertically overlap with a via passing through the base substrate.

According to the flexible circuit board according to the embodiments of the present invention, since a separate test pad is not provided to test whether the wiring pattern is shorted or open, it may have an advantageous effect on the miniaturization of the board.

In addition, during the contact inspection using the probe, while the probe is in contact with the test pattern instead of the via land, it is possible to reduce the occurrence of foreign matter and terminal defects of the via land due to the contact.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a diagram of a flexible circuit board in accordance with one embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. 1.

3 is an enlarged view of a test area of a flexible circuit board according to an exemplary embodiment of the present invention.

4-5 are diagrams of flexible circuit boards in accordance with another embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. The size and relative size of the components shown in the drawings may be exaggerated for clarity of explanation. Like reference numerals refer to like elements throughout the specification, and "and / or" includes each and every combination of one or more of the mentioned items.

When elements or layers are referred to as "on" or "on" of another element or layer, intervening other elements or layers as well as intervening another layer or element in between. It includes everything. On the other hand, when a device is referred to as "directly on" or "directly on" indicates that no device or layer is intervened in the middle.

The spatially relative terms " below ", " beneath ", " lower ", " above ", " upper " It may be used to easily describe the correlation of a device or components with other devices or components. Spatially relative terms are to be understood as including terms in different directions of the device in use or operation in addition to the directions shown in the figures. For example, when flipping a device shown in the figure, a device described as "below" or "beneath" of another device may be placed "above" of another device. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can also be oriented in other directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, "comprises" and / or "comprising" does not exclude the presence or addition of one or more other components in addition to the mentioned components.

Although the first, second, etc. are used to describe various elements or components, these elements or components are of course not limited by these terms. These terms are only used to distinguish one element or component from another element or component. Therefore, the first device or component mentioned below may be a second device or component within the technical idea of the present invention.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. In addition, the terms defined in the commonly used dictionaries are not ideally or excessively interpreted unless they are specifically defined clearly.

1 is a diagram of a flexible circuit board according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. 1.

1 and 2, a flexible circuit board 1 according to an exemplary embodiment of the present invention may include a base substrate 10, a first wiring pattern 15 formed on one surface of the base substrate, and a first connection pad 50. ), A second connection pad 30, a first test pattern 40, a second test pattern 20, and a second wiring pattern 16 formed on the other surface of the base substrate.

The base substrate 10 may be formed of a flexible material and may be included as the substrate in the flexible circuit board 1 to allow the flexible circuit board 1 to be bent or folded. The base substrate 10 may be, for example, a polyimide film. Alternatively, the base substrate 10 may be a PET film, polyethylene naphthalate film, polycarbonate film or insulating metal foil. In the electronic device 1 according to an embodiment of the present invention, the base substrate 10 is described as being a polyimide film.

The first wiring pattern 15 may be formed on one surface of the base substrate 10. For convenience of description, a surface on the base substrate 10 on which the first wiring pattern 15, the first test pattern 40, and the like are disposed is called one surface, and the base substrate on which the second wiring pattern 16 is disposed ( The surface of 10) is described as the other surface. As illustrated in FIG. 1, the first wiring pattern 15 may be a plurality of wiring patterns spaced apart from each other with a predetermined width and interval.

The first wiring pattern 15 may include, for example, a conductive material such as copper, but the present invention is not limited thereto. Specifically, the first wiring pattern 15 may be made of a material having electrical conductivity, such as gold and aluminum.

The first wiring pattern 15 may include at least one subpattern 15_1 and 15_2.

The first wiring patterns 15 may be respectively connected to the first connection pads 50 to transmit electrical signals to the first connection pads 50. In detail, the first sub pattern 15_1 may be connected to the first sub pad 50_1, and the second sub pattern 15_2 may be connected to the second sub pad 50_2.

In addition, the first wiring pattern 15 may be electrically connected to the first test pattern 40 through the first connection pad 50. In detail, the first sub pattern 15_1 may be electrically connected to the first sub test pattern 40_1 through the first sub pad 50_1, and the second sub pattern 15_2 may be the second sub pad 50_2. It may be electrically connected to the second sub test pattern 40_2 through. One end of the first wiring pattern 15 may be connected to the first connection pad 50, and the other end (not shown) may be connected to another pad or connection terminal.

Here, the first connection pad 50 may be, for example, an outer lead for connecting to an external device connected to the flexible circuit board 1, and another pad connected to the other end of the first wiring pattern 15 may be It may be an inner lead on which the driving element is mounted.

In the flexible circuit board 1 according to an embodiment of the present invention, since the short / open test using probe scanning is performed on the test patterns 20 and 40 on the test areas 25 and 35, the first wiring pattern 15 ) May not be exposed and may be covered with a protective layer. For example, at least a portion of the first wiring pattern 15 may be covered with a solder resist.

As illustrated in FIG. 1, the first subpattern 15_1 and the second subpattern 15_2 constituting the first wiring pattern 15 are disposed to extend in the third direction d3, and the first direction ( d1) may be spaced apart from each other, but the present invention is not limited thereto. That is, the arrangement is only one embodiment, and the first subpattern 15_1 and the second subpattern 15_2 extend in the first direction d1 and are spaced apart from each other in the third direction d3, respectively. May be

The first connection pad 50 may be formed on one surface of the base substrate 10. The first connection pad 50 may be connected to the first wiring pattern 15 and may have an extended shape of the first wiring pattern 15.

The first connection pad 50 may include at least one sub pad. As shown in FIG. 1, the first sub pad 50_1 and the second sub pad 50_2 may be included. The first sub pad 50_1 may electrically connect the first sub pattern 15_1 and the first sub test pattern 40_1, and the second sub pad 50_2 may connect the second sub pattern 15_2 and the second sub pattern 15_1. The sub test pattern 40_2 can be electrically connected.

The plurality of first connection pads 50 may be spaced apart from each other at regular intervals to form a first connection pad group 51. For example, the plurality of first connection pads 50 may be arranged side by side in the second direction d2 as illustrated in FIG. 1. Meanwhile, the first connection pads 50 arranged side by side in the second direction d2 may not be overlapped in the first direction d1, but may be disposed to overlap at least a portion in the third direction d3.

This arrangement is to minimize the area required for the arrangement of the first connection pads 50 when the first wiring pattern 15 and the first test pattern 40 are arranged to extend in the third direction d3, respectively. Although it may be an example of the arrangement of the first connection pads 50, the present invention is not limited thereto.

That is, when the first wiring pattern 15 and the first test pattern 40 are arranged to extend in the first direction d1, the first connection pads 50 may be at least partially in the first direction d1. They may be arranged to overlap each other and not overlap each other in the third direction d3.

Like the first wiring pattern 15, the first connection pad 50 may include a material having electrical conductivity such as copper, gold, or an alloy thereof.

The second wiring pattern 16 may be formed on the other surface of the base substrate 10. That is, the second wiring pattern 16 may be formed on opposite surfaces of the first wiring pattern 15 and the base substrate 10. Similar to the first wiring pattern 15, the second wiring pattern 16 may be a plurality of wiring patterns disposed on the other surface of the base substrate 10 and spaced apart from each other at predetermined widths and intervals.

The second wiring pattern 16 may be electrically connected to the second connection pad 30. That is, as shown in FIG. 2, the second wiring pattern 16 may extend on the other surface of the base substrate 10 and be connected to the second connection pad 30. The second wiring pattern 16 may be electrically connected to the second test pattern 20 through the second connection pad 30. Like the first wiring pattern 15, the second wiring pattern 16 may be made of a material having electrical conductivity such as copper, gold, and aluminum.

The second connection pad 30 may include an upper pad 36 and a lower pad 37. The upper pad 36 is connected to the second test pattern 20 formed on one surface of the base substrate 10, and the lower pad 37 is formed on the second wiring pattern formed on the other surface of the base substrate 10. 16).

At least a portion of the upper pad 36 may vertically overlap with the lower pad 37. Meanwhile, the upper pad 36 and the lower pad 37 may be connected through the via 41. The second connection pads 30 may be disposed to vertically overlap the vias 41. For each of the plurality of second connection pads 30 spaced apart from each other in the second direction d2, vias 41 penetrating the base substrate 10 respectively overlap with the plurality of second connection pads 30, respectively. It may be arranged to.

The via 41 may fill the via hole 45 penetrating the base substrate 10 and electrically connect the upper pad 36 and the lower pad 37 to each other. Although the via 41 filling the via hole 45 is illustrated in FIG. 2 as a single layer, the via 41 may be formed in a multilayer structure having two or more layers in which a metal foil layer is formed on the inner wall of the via hole 45. .

The plurality of second connection pads 30 may be spaced apart from each other on one surface of the base substrate 10 at regular intervals to form a second connection pad group 31. The plurality of second connection pads 30 may be arranged side by side in the second direction d2, for example. The plurality of second connection pads 30 may be disposed so as not to overlap each other in the first direction d1 but at least partially overlap the third direction d3.

In this arrangement, when the second test pattern 20 is arranged to extend in the third direction d3, the arrangement of the second connection pads 30 is minimized to minimize the area required for the arrangement of the second connection pads 30. It may be an example of the present invention is not limited.

As described above, when the second test pattern 20 is arranged to extend in the first direction d1, the second connection pads 30 are at least in the first direction d1 to optimize the placement area. Some may overlap and may not be overlapped in the third direction d3.

Like the first connection pad 50, the second connection pad 30 may include an electrically conductive material such as copper, gold, or an alloy thereof.

The second connection pad 30 connects the second wiring pattern 16 on the other surface of the base substrate 10 with the second test pattern 20 on the one surface, and the second wiring pattern on the other surface of the base substrate 10. The circuit element connected to 16 may be electrically connected to the second test pattern 20. Accordingly, the open / short test of the circuit element or the second wiring pattern 16 disposed on the other surface of the base substrate 10 may be performed using the second test pattern 20.

The first test pattern 40 may extend onto the first test area 35 on one surface of the base substrate 10. The first test pattern 40 may extend between the first connection pad 50 and the second connection pad 30.

3 is a diagram illustrating an arrangement of test patterns in a test area of a flexible circuit board according to an exemplary embodiment of the present invention.

In the first test area 35, the first test pattern 40 may extend at a predetermined angle with the extension direction d1 of the first test area 35.

For example, the first test pattern 40 may form an angle of 45 degrees to 135 degrees with respect to the extension direction d1 of the first test region 35. In FIG. 3, the first test area 35 may be divided into a portion 40_1a that forms an extension direction d1 of the first test region 35 at 45 degrees and a portion 40_1b which forms 90 degrees.

That is, in the flexible circuit board 1 according to the embodiment of the present invention, the first test region 35 or the second test region 25 may be probe scanning to perform an open / short test of a circuit element or a wiring pattern. The extension direction d1 of the first test region 35 or the second test region 25 may be a direction in which the probe proceeds in the open / short test. Therefore, when the first or second test patterns 40 and 20 form a predetermined angle with the extending direction d1 of the first or second test areas 35 and 25, the first or second test patterns 40 and 20 may be used. Probe scanning may be performed at an angle with respect to 20).

At this time, when the angle between the extension direction d1 of the first or second test regions 35 and 25 and the first or second test patterns 40 and 20 is smaller than 45 degrees, the probe and the first or second Since the angle at which the two test patterns 40 and 20 intersect is less than 45 degrees, the open / short test may not be performed correctly.

Meanwhile, in some embodiments of the present invention, the width w of the first or second test regions 35 and 25 may be 100 μm or more. That is, the width w of the extending direction of the test area (d1 in FIG. 3) may be 100 μm or more, which means that the probe scanning is 100 μm in the open / short test on the first or second test patterns 40, 20. It means that the above proceeds with a wide margin.

In the flexible circuit board 1 according to an embodiment of the present invention, the first test region 35 may be disposed between the first connection pad 50 and the second connection pad 30, and the second test region 25 may be disposed between an end of the base substrate 10 and the second connection pad 30.

In another embodiment of the present invention, a sprocket hole formed to wind the base substrate 10 in a roll-to-roll process is formed at an end of the base substrate 10, and the second test area 25 is a sprocket hole (not shown). And the second connection pad 30 may be disposed.

The flexible circuit board 1 according to the exemplary embodiment of the present invention does not include a test pad for checking whether the wiring patterns 15 and 16 formed on the base substrate 10 are shorted / open.

Therefore, instead of a separate test pad, test patterns 20 and 40 extending over the test areas 25 and 35 of the base substrate 10 where the probe scanning test is performed are provided, thereby reducing the area of the base substrate 10. It may be advantageous to the flexible circuit board (1).

In addition, probes for the wiring patterns 15 and 16 on both sides of the base substrate 10 are formed by the test patterns 20 and 40 electrically connecting the wiring patterns 15 and 16 on both sides of the base substrate 10. Scanning tests can be performed simultaneously.

4 is a diagram of a flexible circuit board according to another embodiment of the present invention. Hereinafter, a configuration overlapping with the above embodiment will be omitted and the description will be given based on differences.

Referring to FIG. 4, in the flexible circuit board 2 according to another exemplary embodiment, the first test area 35 and the second test area 25 may be adjacent to each other.

The flexible circuit board 1 described above with reference to FIG. 1 has been described in the present embodiment if the second test pattern 20 extends in the direction toward the end of the base substrate 10, that is, in the outward direction of the base substrate 10. The flexible circuit board 2 may include a second test pattern 20 extending in the inward direction of the base substrate 10.

The first test pattern 40 and the second test pattern may extend between the first connection pad 50 and the second connection pad 30. Therefore, the first and second test areas 35 and 25 may also be disposed between the first connection pad 50 and the second connection pad 30 at a predetermined interval and spaced apart from each other.

In another embodiment of the present invention, the first and second test areas 35 and 25 are integrated into one test area, and the first and second test patterns 40 and 20 are included in the integrated test area. The area of the test area may be reduced by intersecting with respect to the probe scanning direction.

5 is a top view of a flexible circuit board according to another embodiment of the present invention.

Referring to FIG. 5, the flexible circuit board 3 according to another embodiment of the present invention may include a first connection pad 50 and a second connection pad 30 disposed adjacent to each other. That is, the first connection pad group 51 configured by arranging the plurality of first connection pads in the second direction d2 and the second connection pad 30 arranged in the second direction d2 are formed of the first connection pad group 51. The two connection pad groups 31 may be disposed adjacent to each other.

As shown in FIG. 5, the first connection pad group 51 including the plurality of first connection pads 50 and the second connection pad group 31 including the plurality of second connection pads 30 may be provided. Although it may be arranged side by side in the second direction (d2), the present invention is not limited thereto. That is, the first connection pad group 51 and the second connection pad group 31 are disposed between the first test region 35 and the second test region 25, and the first and second connection pad groups are ( 51, 31) Embodiments in which the first direction d1 may be arranged side by side may be possible.

As another embodiment of the present invention, the first connection pad 50 may not include the first test pattern 40. In this case, a portion of the first wiring pattern 15 connected to the first test pattern 40 may be selected to be set as the first test region 35 and a probe scanning test may be performed. In this case, the area of the first test pattern 40 can be reduced, thereby reducing the product size.

1, 2, 3: flexible circuit board 10: base substrate

20, 40: test pattern 30, 50: connection pad

25, 35: test area 45: via

150: resist layer 160: protective film

Claims (9)

On one surface, the base substrate in which the test area is defined; At least one first connection pad electrically connected to a first wiring pattern formed on the one surface of the base substrate; At least one second connection pad disposed on the one surface of the base substrate and electrically connected to a second wiring pattern formed on the other surface opposite to the one surface of the base substrate; And And a test pattern extending from the second connection pad onto the test area. The method of claim 1, The test pattern is, A first test pattern extending from the first connection pad onto the test area; And And a second test pattern extending from the second connection pad onto the test area. The method of claim 2, And the first test pattern and the second test pattern are alternately disposed in the test area. The method of claim 2, The test area may include a first test area in which a first test pattern is disposed; And a second test region on which the second test pattern is disposed. The method of claim 4, wherein The first test area or the second test area is disposed between the first connection pad and the second connection pad. The method of claim 4, wherein And the first test region or the second test region is disposed between an end of the flexible circuit board and the first connection pad or the second connection pad. The method of claim 1, And the test area is disposed outside the first connection pad or the second connection pad. The method of claim 1, The test pattern is a flexible circuit board 45 to 135 degrees with respect to the probe scanning progress direction. The method of claim 1, And the second connection pad is electrically connected to the second wiring pattern and vertically overlaps a via penetrating through the base substrate.

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