TWM556992U - Flexible printed circuit board - Google Patents

Abstract

A flexible circuit board includes a flexible base roll and a patterned circuit layer. The flexible base roll is formed by a flexible base rolling up and a length of the flexible base is substantially greater than 500mm. The patterned circuit layer includes a plurality of first circuit portions, a plurality of second circuit portions and a plurality of pad portions respectively connected between the first circuit portions and the second circuit portions, wherein each of the first circuit portions is substantially collinear with the corresponding second circuit portion and connected thereto via the corresponding pad portion.

Description

Flexible circuit board

The novel creation is related to a circuit board, and in particular to a flexible circuit board.

A tape-wound wafer carrier package board (TCP), a chip-on-film flexible board (COF), and a flexible printed circuit board (FPC) are driver integrated circuits of a flat display device such as a liquid crystal display (LCD) and an organic light-emitting display (OLED) ( IC) The most commonly used flexible circuit board for packaging. When these flexible circuit boards are used to bond the display panel and the printed circuit board (PCB), the thermal compression method is usually used, so the reaction temperature needs to be increased to facilitate the electrical pins of the package film and the electrical pins on the display panel. Or the electrical pins on the printed circuit board can be smoothly joined.

However, as the display continues to move toward a larger size, the size of the flexible circuit board increases, but the exposure machine used to make the circuit on the flexible circuit board has a size limitation, thereby making the flexible circuit The size of the board has its limits on the process. Therefore, it is conventional to form a large-sized flexible wiring board by bonding a plurality of flexible wiring boards to each other by a connector. However, the use of connectors to connect lines on multiple flexible boards can affect the transmission speed of the line and can also cause signal loss.

The present invention provides a flexible circuit board that utilizes a multi-stage patterning process to form multi-segment lines connected to each other on a large-sized flexible circuit board.

A method for fabricating a flexible circuit board created by the present invention includes the following steps. Providing a flexible substrate roll which is wound from a soft substrate; a photoresist layer is disposed on the flexible substrate; and a first exposure process is performed on a first portion of the first photoresist layer, Forming a first exposure region on the first segment; performing a second exposure process on a second segment of the photoresist layer to form a second exposure region on the second segment, wherein the first exposure The portion is partially overlapped with the second exposure region; a developing process is performed on the photoresist layer to remove the first exposed region and the second exposed region to form a patterned photoresist layer; and a line process is performed by using the patterned photoresist layer Forming a patterned circuit layer, wherein the patterned circuit layer includes a plurality of first line portions, a plurality of second line portions, and a plurality of pad portions respectively connected between the first line portion and the second line portion; and shifting In addition to the patterned photoresist layer.

In an embodiment of the present invention, a length of the flexible substrate is substantially greater than 500 millimeters (mm).

In an embodiment of the present invention, the first exposure area includes a plurality of first line exposure patterns corresponding to the first line portion and a plurality of pad exposure patterns corresponding to the pad portions, which are respectively connected to the first line exposure. The pattern, the second patterned photoresist layer includes a plurality of second line exposure patterns corresponding to the second line portion.

In an embodiment of the present invention, each of the second line exposure patterns overlaps with each of the pad exposure patterns.

In an embodiment of the present invention, the pad portion is along a soft substrate One length direction is staggered with each other.

In an embodiment of the present invention, each of the pad portions is offset from a side of the flexible substrate by a distance when the first line portions are in a straight line, and each of the first line portions and each of the second portions The line portion is bent and extended to the side to connect the pads.

In an embodiment of the present invention, a width of each of the pad portions is substantially between a line width of each of the second line portions plus 10 micrometers (μm) to 1000 micrometers (μm).

In an embodiment of the present invention, the method for fabricating the flexible circuit board further includes: a first cover film disposed on the flexible substrate; and a second cover film disposed on the flexible substrate, wherein the second cover The film and the first cover film are connected to each other, and a joint surface between the second cover film and the first cover film is located on the pad portion.

A flexible circuit board created by the present invention includes a flexible substrate roll, a first patterned circuit layer, and a second patterned circuit layer. The flexible substrate roll is wound from a flexible substrate and a length of the flexible substrate is substantially greater than 500 mm. The patterned circuit layer includes a plurality of first line portions, a plurality of second line portions, and a plurality of pad portions respectively connected between the first line portion and the second line portion, wherein each of the first line portions and the corresponding first portion respectively The two line portions are substantially collinear and are connected to each other via respective pad portions. .

Based on the above, the embodiment of the present invention can perform a plurality of patterning processes on a flexible substrate having a long length in a plurality of sections to form a plurality of exposure patterns that are connected to each other, and form a patterned circuit layer accordingly, thereby A flexible circuit board having a long length is produced by overcoming the limitations of the process in the case of using a connector. Therefore, in no In the case where a connector is to be used, the linear circuit board of the presently-created embodiment and the manufacturing method thereof can effectively increase the transmission speed of the line, and the loss of the signal can also be reduced.

The above described features and advantages of the present invention will become more apparent and understood from the following description.

100‧‧‧Soft circuit board

110‧‧‧Soft substrate roll, soft substrate

120‧‧‧ patterned circuit layer

122‧‧‧First Line Department

124‧‧‧Pushing Department

126‧‧‧Second Line Department

128‧‧‧Pushing Department

129‧‧‧ Third Line Department

140a‧‧‧ photoresist layer

141‧‧‧ patterned photoresist layer

142‧‧‧First exposure area

142a‧‧‧First line exposure pattern

142b‧‧‧pad exposure pattern

144‧‧‧Second exposure area

144a‧‧‧Second line exposure pattern

146‧‧‧ openings

162‧‧‧First cover film

164‧‧‧second cover film

163‧‧‧ joint surface

D1‧‧‧ length direction

R1‧‧‧ first section

R2‧‧‧ second section

R3‧‧‧ third section

T1‧‧‧ distance

W1‧‧‧Width

W2‧‧‧ line width

1 to FIG. 4 are schematic flow diagrams showing a method of fabricating a flexible circuit board according to an embodiment of the present invention.

4A is a partial top plan view of a flexible circuit board in accordance with another embodiment of the present invention.

FIG. 5 is a partial top plan view of a flexible circuit board in accordance with an embodiment of the present invention.

6 is a partial top plan view of a flexible circuit board in accordance with an embodiment of the present invention.

7 is a partial top plan view of a flexible circuit board in accordance with an embodiment of the present invention.

The above and other technical contents, features and effects of the present invention will be apparent from the following detailed description of the embodiments. Directional terms mentioned in the following examples, such as: "up", "down", "before", "after", "Left", "Right", etc. are only the directions in which the additional drawings are referenced. Therefore, the directional terminology used is for illustrative purposes and is not intended to limit the novel creation. Also, in the following embodiments, the same or similar elements will be given the same or similar reference numerals.

1 to FIG. 4 are schematic flow diagrams showing a method of fabricating a flexible circuit board according to an embodiment of the present invention. The manufacturing method of the flexible circuit board of this embodiment may include the following steps. First, a flexible substrate roll 110 is provided, wherein the flexible substrate roll 110 is formed by winding a flexible substrate integrally formed. It should be noted that FIGS. 1 to 3 of the present embodiment only show a top view of a partial section of the flexible substrate roll 110 after being unfolded. In the present embodiment, the length of the flexible substrate roll 110 is greater than about 500 millimeters (mm), which is the total expanded length of the flexible substrate roll 110. Thus, in the present embodiment, the flexible substrate roll 110 having a long length can be applied to a roll-to-roll process to facilitate mass production, and can be applied to a large-sized electronic device such as a large-sized display device, of course, The embodiments of the novel creation are not limited thereto.

Next, a photoresist layer 140a as shown in FIG. 1 is disposed on the flexible substrate roll 110. Next, a first exposure process is performed on a first segment R1 of the photoresist layer 140a to form a first exposure region 142 on the first segment R1. The first exposure region 142 may include a plurality of first line exposure patterns 142a and a plurality of pad exposure patterns 142b as shown in FIG. 1, which are respectively connected to the first line exposure patterns 142a.

In this embodiment, the photoresist layer 140a may be a positive photoresist, that is, a portion irradiated by the ultraviolet light may cause a chemical reaction to loosen the chemical bond and be easily dissolved by the developer in the subsequent development process. In other words, the portion of the photoresist layer 140a that is exposed (for example, the first exposure region 142) can be removed by the developer solution. Of course, in other embodiments, the photoresist layer 140a may also be a negative photoresist, and the portion irradiated by the ultraviolet light generates a chemical reaction to make the chemical bond strong and is not easily used in the developing process in the subsequent development process. Dissolving, in other words, the portion of the photoresist layer 140a that is not exposed can be removed by dissolution of the developer. In the embodiment in which the photoresist layer 140a is a negative photoresist, the ultraviolet light may be irradiated on a region other than the region enclosed by the first exposure region 142 in FIG. 1 to enclose the region surrounded by the first exposure region 142. It can then be removed by dissolution of the developer.

Next, referring to FIG. 2, a second exposure process is performed on a second segment R2 of the photoresist layer 140a to form a second exposure region 144 on the second segment R2, wherein the first exposure region 142 is The second exposure regions 144 partially overlap. In the present embodiment, the second exposure region 144 may include a plurality of second line exposure patterns 144a. In the present embodiment, the second line exposure pattern 144a in the second exposure region 144 may partially overlap the corresponding pad exposure pattern 142b in the first exposure region 142. In other embodiments, the second exposure region 144 may further include a pad exposure pattern (similar to the pad exposure pattern 142b) for subsequently forming the pad portion 128 as shown in FIG. 4A. In the present embodiment, the first exposure region 142 and the second exposure region 144 on the photoresist layer 140a may be alternately arranged with each other, and the adjacent first exposure region 142 and second exposure region 144 partially overlap each other. With such a configuration, a good connection can be formed between the first exposure region 142 and the second exposure region 144 formed by different exposure processes without causing poor connection due to tolerances, thereby avoiding the pattern formed thereby. The circuit layer 120 generates a gap to cause a disconnection.

Next, referring to FIG. 3, a developing process is performed on the photoresist layer 140a. The patterned photoresist layer 141 as shown in FIG. 3 is formed by removing the first exposure region 142 and the second exposure region 144. In the present embodiment, the developing process may include dissolving the first exposure region 142 and the second exposure region 144 formed in the exposure process by using a developing solution. In the present embodiment, the patterned photoresist layer 141 may include a plurality of openings 146.

Next, referring to FIG. 3 and FIG. 4, a line process is performed by using the patterned photoresist layer 141 to form a patterned circuit layer 120 as shown in FIG. 4 on the flexible substrate roll 110, which includes a plurality of first The line portion 122, the plurality of pad portions 124, and the plurality of second line portions 126, and the pad portion 124 are respectively connected between the first line portion 122 and the second line portion 126, wherein the first line portion 122 corresponds to the first The line exposure pattern 142a, the pad portion 124 corresponds to the pad exposure pattern 142b, and the second line portion 126 corresponds to the second line exposure pattern 144a. In the present embodiment, each of the first line portions 122 is substantially collinear with the corresponding second line portion 126 and connected to each other via a corresponding pad portion 124. In the present embodiment, therefore, the first line portion 122, the pad portion 124, and the second line portion 126 are integrally formed. In the present embodiment, the patterned wiring layer 120 integrally extends to the edge of the flexible substrate roll 110.

For example, in the present embodiment, the patterned wiring layer 120 may be formed by a semi-additive method, that is, the above-described wiring process may include a semi-additive method. In detail, the patterned photoresist layer 141 may include a plurality of openings 146 to plate the mask using the patterned photoresist layer 141 to form the patterned wiring layer 120 as shown in FIG. Therefore, the shape of the opening 146 of the patterned photoresist layer 141 can correspond to (match) the shape of the patterned wiring layer 120 to be formed.

Further. In this embodiment, the photoresist layer 140a is provided in a soft state. Before the substrate roll 110, a sub-layer may be formed on the upper surface of the flexible substrate roll 110 by, for example, a sputtering process, and then the first photoresist layer 140a is disposed on the flexible substrate roll 110, and the first The exposure process, the second exposure process, and the development process form an opening 146 of the patterned photoresist layer 141 to expose the underlying seed layer, and then, a portion of the seed layer exposed by the opening 146 can be used as a conductive path for plating. The patterned circuit layer 120 is formed in the opening 146. Certainly, the embodiment is only used for exemplification. In other embodiments, the patterned circuit layer 120 may also be formed by an additive method or a subtractive method, that is, the above-mentioned line process may further include an additive method or a subtractive method. Cheng Fa. It should be noted that, if the patterned wiring layer 120 is formed by a subtractive method, the patterned photoresist layer 141 is used to cover the region where the patterned wiring layer 120 is to be formed, that is, the patterned photoresist layer. The shape of 141 corresponds (satisfying) to the shape of the patterned wiring layer 120. The embodiment of the present invention does not limit the method of fabricating the patterned wiring layer 120, as long as the patterned wiring layer 120 is formed by using the patterned photoresist layer 141 for the wiring process.

4A is a partial top plan view of a flexible circuit board in accordance with another embodiment of the present invention. It should be noted that the flexible circuit board 100 of the present embodiment is similar to the flexible circuit board of FIG. 4. Therefore, the present embodiment uses the component numbers and parts of the foregoing embodiments, wherein the same reference numerals are used to indicate the same or similar. The components are omitted, and the description of the same technical content is omitted. For the description of the omitted part, reference may be made to the foregoing embodiment, and the description is not repeated herein. The difference between the flexible wiring board 100 of the present embodiment and the flexible wiring board of FIG. 4 will be described below.

Referring to FIG. 4A, in the embodiment, the pattern of the second segment R2 is located. The circuit layer 120 may further include a plurality of pad portions 128 to facilitate engagement with the line portion 129 of the next segment (e.g., the third segment R3). The line portion 129 of the third segment R3 can be formed, for example, in a manner similar to the line portion 122 of the first segment R1 to engage with the pad portion 128 of the second segment R2. That is, in this embodiment, the three-stage exposure process may be respectively performed on the photoresist layer 140a on the first segment R1, the second segment R2, and the third segment R3 to form three exposure regions partially overlapping each other. Thereafter, the developing process and the line process are performed to form the patterned wiring layer 120 in which the three-section line portions 122, 126, and 129 are connected to each other as shown in FIG. 4A. Of course, the exposure pattern of the exposed region of the third segment R3 may be different from the first exposure region 142 of the first segment R1. That is, in the embodiment shown in FIG. 4, the patterned circuit layer 120 may be composed of a first segment R1 and a line portion and a pad portion of the second segment R2 being joined to each other. However, the present embodiment The example does not limit the number of exposure areas and the number of exposure processes. Therefore, the inventive embodiment can be segmented on a flexible substrate 110 having a long length (at least about 500 mm) (for example: first segment R1, second segment R2, third segment R3... And so on) a plurality of exposure processes are performed to form a plurality of exposure regions that are coupled to each other and partially overlap. Thus, the flexible wiring board 100 having a long length (at least about 500 mm) can be produced by overcoming the limitation of the size of the exposure machine without connecting the plurality of flexible substrates using the connector. In one embodiment, the flexible circuit board 100 as shown in FIG. 4 or FIG. 4A produced by the above process can be regarded as a panel, and the plurality of tiles can be connected to each other (for example, through a connector to each other) Connect) to form a flexible circuit board with a longer line length. It should be noted that the pad portions 124 and 128 of the embodiment are used for connecting the first line portion 122, the second line portion 126, and the The dummy pads of the three line portions 129 are not used for component mounting, that is, the pad portions 124, 128 are not connected to other electronic components, and are not connected to the other underneath. Hole connection.

FIG. 5 is a partial top plan view of a flexible circuit board in accordance with an embodiment of the present invention. Referring to FIG. 5, in the embodiment, after the patterned circuit layer 120 is formed, a first coverlay 162 may be selectively formed on the flexible substrate roll 110, wherein the first cover film 162 is covered. The first line portion 122 and at least a portion of the pad portion 124. Next, a second cover film 164 may be formed on the flexible substrate roll 110, wherein the second cover film 164 covers the second line portion 126 and the other portion of the pad portion 124 that is not covered by the first cover film 162. In this embodiment, the second cover film 164 and the first cover film 162 are connected to each other, and a joint surface 163 between the second cover film 164 and the first cover film 162 is located on the pad portion 124, that is, The first cover film 162 and the second cover film 164 are joined to each other on the pad portion 124 and collectively cover the pad portion 124. In this embodiment, the material of the first cover film 162 and the second cover film 164 may include polyimide (PI).

Referring to FIG. 4 and FIG. 5 , in the embodiment, the flexible circuit board 100 formed according to the above manufacturing method may include a flexible substrate roll 110 and a patterned circuit layer 120 . The flexible substrate roll 110 is formed by winding a flexible substrate integrally formed. The patterned circuit layer 120 includes a plurality of first line portions 122, a plurality of second line portions 126, and a plurality of pad portions 124 connected between the first line portion 122 and the second line portion 126, respectively, wherein each of the first lines The line portions 122 are substantially collinear with the respective second line portions 126 and are connected to each other via respective pad portions 124.

In the embodiment, the arrangement in which the second exposure region 144 slightly overlaps with the first exposure region 142 can effectively prevent the second line portion 126 and the pad portion formed according to the tolerance offset in the longitudinal direction D1. A case where a gap is generated in the longitudinal direction D1 to cause a disconnection. Moreover, the width of the pad exposure pattern is designed to be larger than the width of each of the second line exposure patterns 144a, so that the second line formed thereby due to the tolerance offset in the width direction (perpendicular to the length direction D1) can be effectively prevented. The portion 126 and the pad portion 124 have a gap in the width direction to cause a disconnection. Therefore, the width W1 of each of the pad portions 124 formed is larger than the line width W2 of each of the second line portions 126. For example, a width W1 of each pad portion 124 is approximately between a line width W2 and a range of 10 μm to 1000 μm of each of the second line portions 126. That is, the width W1 of each of the pad portions 124 is approximately one line width W2 of each of the second line portions 126 plus 10 μm to 1000 μm. Therefore, the configuration of the embodiment can further improve the tolerance when the first exposure region 142 and the second exposure region 144 are connected to each other, thereby improving the yield of the flexible circuit board 100 of the embodiment.

In addition, the flexible circuit board 100 of the present embodiment further includes a first cover film 162 and a second cover film 164 as shown in FIG. 5. The first cover film 162 is disposed on the flexible substrate roll 110 and covers the first line portion 122 and at least a portion of the pad portion 124. The second cover film 164 is disposed on the flexible substrate roll 110 and covers the second line portion 126 and the other portion of the pad portion 124 that is not covered by the first cover film 162. In this embodiment, the positions of the second cover film 164 and the first cover film 162 on the flexible substrate 110 may be the same or different from the first segment R1 and the second segment R2, respectively.

6 is a partial top plan view of a flexible circuit board in accordance with an embodiment of the present invention. 7 is a partial top plan view of a flexible circuit board in accordance with an embodiment of the present invention. It should be noted that the flexible circuit board 100 of the embodiment of FIG. 6 and FIG. 7 is similar to the flexible circuit board 100 of FIG. 4. Therefore, the present embodiment follows the component numbers and parts of the foregoing embodiments, wherein the same is used. The reference numerals are given to the same or similar elements, and the description of the same technical content is omitted. For the description of the omitted part, reference may be made to the foregoing embodiment, and the description is not repeated herein. Referring to FIG. 1 and FIG. 3, differences between the flexible wiring board 100 of FIGS. 6 and 7 and the flexible wiring board 100 of FIG. 4 will be described below.

As described above, in order to ensure that the first exposed region 142 and the second exposed region 144 which are successively formed in the two segments are not caused to be broken due to the tolerance, the width of the pad portion 124 is broken. Usually it is larger than the line width. With this configuration, in the case of a required fine pitch, the pad portions 124 may be alternately arranged with each other along the longitudinal direction D1 of the flexible substrate roll 110 to further reduce the relationship between the line portions 122, 126. spacing. Referring to FIG. 7 , in other embodiments, each of the pad portions 124 may be offset from a side (eg, an upper side) of the flexible substrate roll 110 by a distance when the first line portions 122 are in a straight line. In T1, each of the first line portions 122 and each of the second line portions 126 is bent and extended to the side to connect the pads 124. Of course, the embodiments of the present invention are merely for exemplification, and the present invention does not limit the layout and arrangement between the first line portion 122, the pad portion 124, and the second line portion 126.

In summary, the embodiment of the novel creation can be a soft base with a long length. The plate is divided into sections to perform a plurality of exposure processes to respectively form a plurality of exposure regions which are spaced apart from each other and are connected to each other, thereby overcoming the limitation of the size of the exposure machine without connecting the plurality of flexible substrates with the connector. A flexible circuit board having a long length and being integrally formed can be produced. In addition, the linear circuit board of the present invention and the manufacturing method thereof can effectively improve the transmission speed of the line and reduce the loss of the signal, without using a connector to connect the plurality of flexible substrates.

In addition, the multi-segment exposure processes may partially overlap, and thus, the plurality of exposure regions formed by the segments may partially overlap each other, thereby avoiding a situation in which disconnection occurs between the plurality of exposure regions due to process tolerances. Therefore, the linear circuit board of the novel creation embodiment and the manufacturing method thereof can effectively improve the process yield thereof.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the novel creation, and any person skilled in the art can make some changes without departing from the spirit and scope of the novel creation. Retouching, the scope of protection of this new creation is subject to the definition of the scope of the patent application attached.

Claims (5)

A flexible circuit board comprising: a flexible substrate roll wound from a flexible substrate formed integrally and having a length substantially greater than 500 mm; a patterned circuit layer disposed thereon The flexible substrate roll includes a plurality of first line portions, a plurality of second line portions, and a plurality of pad portions, wherein the pad portions are respectively connected to the first line portions and the second line portions And each of the first line portions is substantially collinear with the corresponding second line portion and connected to each other via a corresponding pad portion. The flexible circuit board of claim 1, wherein the pad portions are staggered with each other along a length direction of the flexible substrate. The flexible circuit board according to claim 1, wherein each of the pad portions is offset from a side of the flexible substrate by a distance from each of the first line portions. A line portion and each of the second line portions are bent and extended to the side to connect the pads. The flexible circuit board of claim 1, wherein a width of each of the pad portions is substantially between a line width of each of the second line portions plus 10 micrometers (μm) to 1000 micrometers (μm) . The flexible circuit board of claim 1, further comprising: a first cover film disposed on the flexible substrate; and a second cover film disposed on the flexible substrate, wherein the second a cover film and the first cover film are connected to each other, and between the second cover film and the first cover film A joint surface is located on the plurality of pad portions.