Flexible circuit board, flexible circuit board structure, electronic device including flexible circuit board, and method for manufacturing a flexible circuit board

Abstract

A flexible circuit board, a flexible circuit board structure, an electronic device including a flexible circuit board, and a method for manufacturing a flexible circuit board are disclosed. A flexible circuit board structure according to one aspect of the present invention includes at least one flexible circuit board, a support substrate partially separated from the flexible circuit board by cutting holes that partially surround the side surface of the flexible circuit board, and at least one bridge that partially connects and supports the flexible circuit board with respect to the support substrate, wherein the bridge is formed such that its width narrows from one end to the other in the thickness direction.

Description

TECHNICAL FIELD

[0001] The present invention relates to a flexible circuit board, a flexible circuit board structure, an electronic apparatus including the flexible circuit board, and a method for manufacturing the flexible circuit board.

[0002] Electronic devices such as camera modules, inductors and antennas include coils, and the coils are classified into a winding type using copper wires, a lamination type in which green sheets are laminated, and a thin film type in which coils are formed through a plating process.

[0003] Among these, in the case of a thin-film type coil (hereinafter referred to as a flexible circuit board), a plurality of flexible circuit boards are individually separated from a mother board on which the flexible circuit boards are defined and formed, and then assembled into an electronic device or adopted in a bonding manner. At this time, in order to facilitate individual separation of the flexible circuit boards from the mother board, a conventional method of forming a plurality of bridges on the outer peripheral surface of the flexible circuit board by means of laser processing or the like has been adopted.

[0004] However, the following problems arise when the thickness of the circuit wiring is large, or the flexible circuit board has a large total thickness due to multi-layer lamination.

[0005] i) A deformed burr of the bridge remaining on the outer peripheral surface of the separated flexible circuit board protrudes, which degrades the assemblability with the electronic device.

[0006] ii) When the number of repeated laser processing operations during the bridge forming operation is increased, the operation time and cost increase.

[0007] iii) By performing processing with an increased laser beam intensity during the bridge forming operation, the surface of the flexible circuit board is instead carbonized, or thermal oxidation and the like occur.

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] The present invention aims to solve the aforementioned problems and to provide a flexible circuit board configured to minimize the size of so-called burrs, which are fractured remnants remaining on the side surface of the flexible circuit board due to bridge fracture, a flexible circuit board structure including the same, and a method for manufacturing a flexible circuit board.

[0009] Another object of the present invention is to provide a flexible circuit board manufacturing method configured to reduce time and cost and perform effective bridge formation work. [Means for solving the problem]

[0010] According to one aspect of the present invention, a flexible circuit board structure is provided, comprising at least one flexible circuit board, a support substrate partially separated from the flexible circuit board by cutting holes that partially surround the side surface of the flexible circuit board, and at least one bridge that partially connects and supports the flexible circuit board with respect to the support substrate, wherein the bridge is formed such that its width narrows from one end to the other in the thickness direction.

[0011] In this case, the bridge may be formed as an extension between the sides of the flexible circuit board and the side of the support board, which face each other with respect to the cutting hole.

[0012] In this case, the cross-section perpendicular to the extension direction of the bridge may have a triangular or trapezoidal shape.

[0013] On the other hand, the average extension length of the bridge may be less than 100 μm.

[0014] On the other hand, the width of the shorter end, which has a relatively smaller width, among the ends of the bridge in the thickness direction, may be 0% or more and 50% or less of the width of the longer end, which has a relatively larger width.

[0015] On the other hand, the width of the long end, which has a relatively large width among the ends of the bridge in the thickness direction, may be 60 μm or more and 140 μm or less.

[0016] On the other hand, the longer end of the bridge, which has a relatively large width among the ends in the thickness direction, is in contact with one end in the thickness direction of the side surface of the flexible circuit board facing the cutting hole, and the shorter end of the bridge, which has a relatively small width among the ends in the thickness direction, may or may not be in contact with the other end in the thickness direction of the side surface of the flexible circuit board.

[0017] On the other hand, the thickness of the bridge may be 50% to 100% of the thickness of the side surface of the flexible circuit board facing the cutting hole.

[0018] According to another aspect of the present invention, a method for manufacturing a flexible circuit board is provided, comprising: a base substrate generation step of creating a base substrate by forming one or more flexible circuit boards having a circuit pattern on a base substrate; and a bridge formation step of partially cutting the periphery of the flexible circuit board so that the base substrate is divided into the flexible circuit board and a support substrate, thereby forming a bridge that partially supports the flexible circuit board on the support substrate, wherein the bridge is formed such that its width decreases from one end to the other in the thickness direction.

[0019] At this time, during the master substrate generation stage, a circuit pattern may be formed on at least one flexible circuit board region provided on the base substrate.

[0020] On the other hand, during the bridge formation stage, the periphery of the flexible circuit board formed on the base substrate can be cut via laser drilling.

[0021] In this case, during the bridge formation stage, the laser drilling can be performed by varying the focus of the laser beam according to the processing depth.

[0022] On the other hand, the method for manufacturing a flexible circuit board may further include a flexible circuit board separation step of breaking the bridge to separate the flexible circuit board from the support substrate.

[0023] According to still another aspect of the present invention, there is provided a flexible circuit board separated from a support substrate by breaking a bridge connected to the support substrate, wherein a break residue resulting from breaking of the bridge is formed on a side surface of the flexible circuit board in contact with the bridge, and the bridge is characterized in that the width thereof decreases from one of both end portions in the thickness direction toward the other end portion side.

[0024] According to another aspect of the present invention, an electronic apparatus comprising the flexible circuit board is provided. Advantageous Effects of the Invention

[0025] In the flexible circuit board and the flexible circuit board structure including the same according to one aspect of the present invention, the bridge is formed such that the width thereof decreases from one of both end portions in the thickness direction toward the other end portion side, so that the bridge has better breakability than a conventional bridge having a constant width in the width direction, and the protruding length of the break residue remaining on the side surface of the flexible circuit board after breaking can be shortened. If the length of the break residue is shortened, the ease of assembly with an electronic device when the flexible circuit board is used can be improved.

[0026] In the method for manufacturing a flexible circuit board according to one aspect of the present invention, the bridge connected to the side surface of the flexible circuit board is formed such that the width thereof decreases from one of both end portions in the thickness direction toward the other end portion side, whereby it is possible to provide a flexible circuit board structure and a flexible circuit board which have good breakability of the bridge and a short protruding length of the break residue.

[0027] Furthermore, by performing laser drilling while adjusting the focus of the laser beam according to the processing depth in the bridge formation step, it is possible to provide thermal energy optimized corresponding to the processing depth, thereby enabling effective, efficient and economical cutting.

[0028] The effects of the present invention are not limited to the aforementioned effects, and should be understood to include all effects that can be inferred from the configurations of the invention described in the present specification or the appended claims. [Brief Description of the Drawings]

[0029] Figure 1 is a drawing showing a flexible circuit board structure including a flexible circuit board according to an embodiment of the present invention.

[0030] Figure 2 is a cross-sectional view taken along line I-I of Figure 1.

[0031] Figure 3 is a cross-sectional view taken along line II-II of Figure 2.

[0032] Figure 4 is a diagram showing a modified example of the cross-section of the bridge shown in Figure 3.

[0033] Figure 5 is a diagram showing the fracture test results of a conventional bridge having a constant width in the thickness direction in the prior art.

[0034] Figure 6 is a drawing showing the fracture test results of a bridge whose width narrows in the thickness direction according to an embodiment of the present invention.

[0035] Figure 7 is a sequence diagram of a method for manufacturing a flexible circuit board according to an embodiment of the present invention.

[0036] Figure 8 is a diagram for explaining a part of a method for manufacturing a flexible circuit board according to an embodiment of the present invention.

[0037] Figure 9 is a cross-sectional view taken along line III-III of Figure 8.

[0038] Figure 10 is a diagram illustrating a part of a flexible circuit board manufacturing method according to one embodiment of the present invention.

[0039] Figure 11 is a cross-sectional view taken along line IV-IV of Figure 10.

[0040] Figure 12 shows the process of laser drilling in a flexible circuit board manufacturing method according to one embodiment of the present invention, in which the focus is adjusted according to the processing depth.

[0041] Figure 13 shows the flexible circuit board separated from the support substrate after the bridge was broken in Figure 10. [Modes for carrying out the invention]

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings, in a manner that can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. The present invention can be embodied in a variety of different forms and is not limited to the embodiments described herein. For clarity in illustrating the present invention, parts of the drawings that are not relevant to the description have been omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

[0043] The words and terms used herein and in the claims shall not be interpreted to be limited to their ordinary or dictionary meanings, but rather to be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors can define terms and concepts in order to best describe their invention.

[0044] Therefore, the embodiments and configurations shown in the drawings described herein constitute a preferred embodiment of the present invention and do not represent the entire technical concept of the present invention; there may be various equivalents and modifications of such configurations that can be substituted at the time of filing.

[0045] In this specification, terms such as “comprise” and “have” are intended to describe the presence of features, figures, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preemptively exclude the presence or possibility of adding one or more other features, figures, steps, operations, components, parts, or combinations thereof.

[0046] The position of one component "in front of," "behind," "above," or "below" another component includes, unless otherwise specified, not only cases where the component is directly in contact with the other component and positioned "in front of," "behind," "above," or "below," but also cases where another component is positioned between them. Furthermore, the position of one component "connected" to another component includes, unless otherwise specified, cases where the component is directly connected to each other, but also cases where the component is connected through each other.

[0047] In the following, a flexible circuit board structure according to one embodiment of the present invention will be described with reference to the drawings.

[0048] Figure 1 shows a flexible circuit board structure including a flexible circuit board according to one embodiment of the present invention, Figure 2 is a cross-sectional view II of Figure 1, and Figure 3 is a cross-sectional view taken along line II-II of Figure 2.

[0049] Referring to Figures 1 to 3, a flexible circuit board structure 10 according to one embodiment of the present invention is composed of a flexible circuit board 100, a support substrate 300, and a bridge 500.

[0050] The flexible circuit board 100 includes a base substrate 110, a circuit pattern 130, and an insulating layer 150.

[0051] The base substrate (110) is manufactured using a polymer such as polyimide as the main component. The base substrate (110) is formed into a film type.

[0052] The circuit pattern 130 can be formed on both sides of the base substrate 110, as shown in Figure 2. However, although not shown, the circuit pattern may also be formed on one side of the base substrate 110.

[0053] The circuit pattern 130 may be formed by a photolithography process, but is not limited thereto, and may be formed on one or both sides of the base substrate 110 by a known method.

[0054] The circuit pattern 130 formed on the base substrate 110 can be formed as a single-layer structure as shown in Figure 2, but is not limited to this, and may be formed as a multi-layer structure.

[0055] The insulating layer 150 covers and protects the circuit pattern 130.

[0056] The flexible circuit board structure 10 according to this embodiment includes two flexible circuit boards 100 as shown in Figures 2 and 3, but this is merely an example, and it may be configured to include one or three or more flexible circuit boards.

[0057] The flexible circuit board 100 is partially separated from the support substrate 300 by cutting holes 200 that partially surround its side surface 101.

[0058] The support substrate 300 is configured to support the flexible circuit board 100, which is partially connected and supported by the bridge 500.

[0059] In the manufacturing process of the flexible circuit board described later, the support substrate 300 and the flexible circuit board 100 are completely connected and formed as a single unit without the cutting holes 200. A substrate in this form, where the support substrate 300 and the flexible circuit board 100 are integrated before the cutting holes 200 are formed, is called a master substrate (not shown).

[0060] When cutting holes 200 are partially formed around the flexible circuit board 100 formed on the base substrate, the flexible circuit board 100 and the support substrate 300 are partially separated and divided by the cutting holes 200.

[0061] In other words, when cutting holes 200 are partially formed around the periphery of the flexible circuit board 100 formed on the base substrate, the flexible circuit board 100 is partially connected to the support substrate 300 by the uncut portion around the flexible circuit board 100.

[0062] In this configuration, the portion partially connecting the flexible circuit board 100 and the support substrate 300 becomes a bridge 500. The flexible circuit board 100, separated by the cutting holes 200, can be partially supported by the support substrate 300 by the bridge 500.

[0063] The bridge 500 is broken to completely separate the flexible circuit board 100 from the support board 300.

[0064] In this embodiment, four bridges 500 are formed on one flexible circuit board 100, but this is merely an example, and the number of bridges formed on one flexible circuit board may be one or more.

[0065] The bridge 500 is formed extending between the side surfaces 101 of the flexible circuit board 100 and the side surface 301 of the support board 300, which face each other, with the cutting hole 200 as the center.

[0066] In this embodiment, the bridge 500 is formed such that its width narrows along the thickness direction (Z-axis direction in Figure 3) from one end to the other.

[0067] For example, a cross-section perpendicular to the extension direction (for example, the X-axis direction in Figure 3) of a bridge 500 formed to narrow in the thickness direction can have a trapezoidal shape, as shown in Figure 3.

[0068] Alternatively, as shown in Figure 4, a bridge 500' formed to narrow in the thickness direction may have a triangular cross-section perpendicular to the extension direction. For reference, Figure 4 shows a modified example of the cross-section of the bridge shown in Figure 3.

[0069] If the bridge 500 is formed such that its width narrows from one end towards the other in the thickness direction, compared to a conventional bridge 500 with a constant width in the thickness direction, the bridge 500 becomes more prone to fracture at the narrower portion in the thickness direction. This can shorten the length of the fractured residue, or burr, remaining on the side surface 101 of the flexible circuit board 100 after the bridge 500 has fractured. A shorter fractured residue can improve the ease of assembly with electronic devices when using the flexible circuit board 100.

[0070] In this regard, Figure 5 shows the fracture experiment results of a conventional bridge having a constant width in the thickness direction, and Figure 6 shows the fracture experiment results of a bridge with a narrower width in the thickness direction according to one embodiment of the present invention. For reference, Figure 6 shows the experimental results for a bridge having a triangular cross-section similar to that in Figure 4.

[0071] Referring to Figure 5(a), it can be seen that, in the conventional case, when a bridge is fractured, the fractured residue (K0), also known as a burr, remaining on the flexible circuit board (M0) has a certain width in the thickness direction.

[0072] Referring to Figure 5(b), the fractured remnants (K0) of a conventional bridge are found on a flexible circuit board (M O The extent to which it protrudes from the side of ) can be determined. Figure 6(b) shows the fractured residue (K O The average protrusion length of the ) is 62 μm.

[0073] Referring to Figure 6(a), it can be seen that, as a result of fracturing the bridge according to this embodiment, the fractured remnant (K1) remaining on the flexible circuit board (M1) has a narrower width in the thickness direction and also has a triangular cross-section.

[0074] Referring to Figure 6(b), the extent to which the fractured bridge remnants K1 in this embodiment protrude from the side surface of the flexible circuit board M1 can be seen. In Figure 7(b), the average protrusion length of the fractured remnants K1 is 45 μm.

[0075] Through such experiments, it was found that the bridges 500 and 500' according to this embodiment, which are formed such that the width narrows from one end towards the other in the thickness direction, can shorten the protruding length of the fractured remnants remaining on the side surface 101 of the flexible circuit board 100 after fracture, compared to conventional bridges in which the width in the thickness direction is constant.

[0076] Referring to Figure 3, the width of the relatively smaller short end (B2) at both ends of the bridge 500 in the thickness direction may be between 0% and 50% of the width of the relatively larger long end (B1). In other words, the width of the relatively smaller short end (B2) at both ends of the bridge 500 in the thickness direction may be between 0 and 0.5 times the width of the relatively larger long end (B1).

[0077] For example, if the width of the short end (B2) of the bridge 500 is 50% of the width of the long end (B1), the cross-section of the bridge 500 can have a trapezoidal shape as shown in Figure 3.

[0078] Furthermore, if the width of the short end (B2) of bridge 500 in Figure 3 is 0% of the width of the long end (B1), then bridge 500' can have a triangular cross-section as shown in Figure 4.

[0079] As the width of the short end (B2) of the bridge 500 approaches 0% of the width of the long end (B1), the ease with which the bridge 500 breaks improves, and the size of the fractured residue remaining on the side surface 101 of the flexible circuit board 100 also decreases.

[0080] If the width of the short end (B2) of the bridge 500 exceeds 50% of the width of the long end (B1), the ease of fracture is low, similar to conventional bridges where the width in the thickness direction of the bridge 500 is constant, and the size of the fractured residue remaining on the side surface 101 of the flexible circuit board 100 is also large.

[0081] Referring to Figure 3, the longer end of the bridge 500 in the thickness direction can contact one end of the side surface 101 of the flexible circuit board 100 facing the cutting hole 200 in the thickness direction (Z-axis direction in Figure 3), and the shorter end of the bridge 500 in the thickness direction can contact the other end of the side surface 101 of the flexible circuit board 100 facing the cutting hole 200 in the thickness direction.

[0082] However, although not shown in the diagram, the longer end of the bridge in the thickness direction may be in contact with one end of the side surface of the flexible circuit board facing the cutting hole in the thickness direction, and the shorter end of the bridge in the thickness direction may be in contact with the other end of the side surface of the flexible circuit board facing the cutting hole in the thickness direction, or it may not be in contact with it.

[0083] In this embodiment, the thickness (t1) of the bridge 500 may be 50% or more and 100% or less of the thickness (t0) of the side surface 101 of the flexible circuit board 100 facing the cutting hole 200.

[0084] If the thickness t1 of the bridge 500 is 100% of the thickness t0 of the side surface 101 of the flexible circuit board 100 facing the cutting hole 200, then, as shown in Figure 3, both ends of the bridge 500 in the thickness direction will be in contact with both ends of the side surface 101 of the flexible circuit board 100 in the thickness direction.

[0085] If the thickness t1 of the bridge 500 is less than 50% of the thickness t0 of the side surface 101 of the flexible circuit board 100 facing the cutting hole 200, the support force of the bridge 500 supporting the flexible circuit board 100 against the support substrate 300 may be significantly reduced.

[0086] Referring to Figure 2, the average extension length of the bridge 500 may be 100 μm or less. Preferably, the average extension length of the bridge 500 may be 20 μm or more and 100 μm or less. The extension length of the bridge 500, which extends from the side surface 101 of the flexible circuit board 100 to the side surface 301 of the support board 300 at the center of the cutting hole 200, may have a shape in which one end of the two ends in the thickness direction (Z-axis direction in Figure 2) of the bridge 500 is longer than the other end. In this case, the average extension length of the bridge 500 can be obtained by taking the average of the different extension lengths in the thickness direction of the bridge 500.

[0087] If the average extension length of the bridge 500 is greater than 100 μm, the protruding length of the fractured remnant remaining on the side surface 101 of the flexible circuit board 100 when the bridge 500 breaks increases. This also reduces the integration density of the substrate array, leading to increased costs.

[0088] If the average extension length of Bridge 500 is less than 20 μm, the ease of fracture of Bridge 500 decreases.

[0089] Referring to Figure 3, the width (B1) of the long end of bridge 500 can be between 60 μm and 140 μm.

[0090] If the width (B1) of the long end of Bridge 500 is less than 60 μm, the bearing capacity may decrease.

[0091] If the width (B1) of the long end of the bridge 500 is greater than 140 μm, the protruding length of the fractured residue remaining on the side surface 101 of the flexible circuit board 100 increases.

[0092] The flexible circuit board structure 10 according to this embodiment, as described above, has a structure in which the flexible circuit board 100 is partially supported on the support substrate 300 by a bridge 500. This allows for the handling of multiple flexible circuit boards 100 at once during inspection, movement, or storage, and the flexible circuit boards 100 are protected and stable by the support substrate 300.

[0093] Furthermore, the bridge 500 constituting the flexible circuit board structure 10 is formed such that its width narrows from one end towards the other end of the two ends in the thickness direction. Compared to conventional bridges with a constant width in the width direction, the bridge 500 is easier to break, and the length of the protruding fragments formed on the side surface 101 of the flexible circuit board 100 after breakage can be shortened. A shorter length of fragments improves the ease of assembly of the flexible circuit board 100 with electronic devices during use.

[0094] Figure 7 is a sequence diagram of a method for manufacturing a flexible circuit board according to one embodiment of the present invention, Figure 8 is a diagram illustrating a part of the method for manufacturing a flexible circuit board according to one embodiment of the present invention, Figure 9 is a cross-sectional view taken along line III-III of Figure 8, Figure 10 is a diagram illustrating a part of the method for manufacturing a flexible circuit board according to one embodiment of the present invention, and Figure 11 is a cross-sectional view taken along line IV-IV of Figure 10.

[0095] Referring to Figures 7, 8, and 9, the method for manufacturing a flexible circuit board according to this embodiment can include a master board generation step (S110) and a bridge formation step (S130).

[0096] The master substrate generation step (S110) is a step in which a master substrate 5 is generated by forming one or more flexible circuit boards 100 equipped with circuit patterns 130 on a base substrate 110.

[0097] In the master substrate generation step (S110), a base substrate (110) is provided. The base substrate (110) can be made mainly from a polymer such as polyimide. The base substrate (110) is formed into a film type.

[0098] A circuit pattern 130 is formed on one or both sides of the provided base substrate 110. At this time, the circuit pattern 130 may be formed on the base substrate by a photolithography process, but is not limited to this, and may be formed on the base substrate 110 by various known methods.

[0099] The circuit pattern 130 can be formed in a single-layer or multi-layer structure. The circuit pattern 130 is formed in at least one flexible circuit board region (A) provided on the base substrate (110).

[0100] Once a circuit pattern 130 is formed on the flexible circuit board region (A), an insulating layer 150 may be provided to prevent the circuit pattern 130 from being exposed to the outside. The insulating layer 150 may be applied not only to the flexible circuit board region (A) of the base substrate 110 but also to the remaining portion.

[0101] A base substrate 5 can be produced in which one or more flexible circuit boards 100 equipped with circuit patterns 130 are formed through the process described above. The base substrate 5 has a substrate form in which at least one or more flexible circuit boards 100 are formed integrally with its surroundings without being separated.

[0102] The flexible circuit board 100 that makes up the master board 5 is only not separated from its surroundings; if it were separated from the master board 5, it would be a board that could perform its designed function.

[0103] Referring to Figures 7, 10, and 11, the bridge formation step (S130) is the step of partially cutting the periphery of the flexible circuit board 100 so that the base substrate (5 in Figure 8) is divided into the flexible circuit board 100 and the support substrate 300, thereby forming a bridge 500 that partially supports the flexible circuit board 100 on the support substrate 300.

[0104] During the bridge formation stage (S130), the periphery of the flexible circuit board 100 formed on the base substrate 5 shown in Figure 8 is partially cut. Once the cutting holes 200 are formed on the base substrate 5 shown in Figure 8, the flexible circuit board 100 and the support substrate 300 are partially separated and partitioned.

[0105] At this time, the portion of the flexible circuit board 100 where no cutting holes 200 are formed becomes a bridge 500, and the bridge 500 partially supports the flexible circuit board 100 on the support substrate 300.

[0106] During the bridge formation stage (S130), when cutting the master substrate (Figure 8, 5), a temporary cutting line (CL) is defined around the flexible circuit board 100 formed on the master substrate (Figure 8, 5). The periphery of the flexible circuit board 100 is partially cut along the cutting line (CL).

[0107] During the bridge formation stage (S130), the area around the flexible circuit board 100 on the base substrate shown in Figure 8, part 5, can be cut by laser drilling.

[0108] In this embodiment, laser drilling can be performed by changing the focus of the laser beam according to the processing depth. When the laser beam is irradiated around the flexible circuit board 100 formed on the base substrate (5 in Figure 8), the thickness of the flexible circuit board 100 around the edges gradually decreases, and a cutting hole 200 is formed.

[0109] In other words, when a laser beam is shone around the flexible circuit board 100 formed on the base substrate (5 in Figure 8), the holes formed around the flexible circuit board 100 gradually deepen, and cutting holes 200 are formed.

[0110] When the processing depths of the holes formed around the flexible circuit board 100 formed on the base substrate (Figure 8, 5) differ, the cutting holes 200 can be formed efficiently and effectively by adjusting the focus of the laser beam according to the different processing depths.

[0111] Figure 12 is a diagram showing a laser drilling process in a flexible circuit board manufacturing method according to one embodiment of the present invention, in which the focus is adjusted according to the processing depth.

[0112] Figure 12(a) shows the case with the shallowest machining depth, Figure 12(b) shows the case with an intermediate machining depth, and Figure 12(c) shows the case with the deepest machining depth.

[0113] Laser drilling allows for three adjustments to the laser beam focus, corresponding to the three machining depths shown in Figures 12(a) to 12(c). However, there is no limit to the number of times the laser beam focus can be adjusted.

[0114] By adjusting the laser beam focus according to the processing depth in this way, it is possible to provide optimized thermal energy corresponding to that processing depth, enabling effective, efficient, and economical cutting.

[0115] On the other hand, when laser drilling, if the laser beam focus is fixed to a single point, defocus increases as the machining depth increases, which can reduce cutting efficiency. However, the laser drilling method described in this embodiment, which changes the focus according to the machining depth, is different from this.

[0116] Furthermore, when increasing the intensity of the laser beam during bridge formation, problems such as carbonization or thermal oxidation of the flexible circuit board surface can occur. However, the laser drilling method described in this embodiment, which changes the focus according to the processing depth, is different from this.

[0117] Furthermore, while increasing only the number of passes during laser drilling can lead to increased working time and costs, the laser drilling method in this embodiment, which changes the focus according to the processing depth, does not cause such problems.

[0118] Referring to Figure 12, the processing area that is irradiated with a laser beam and processed into a concave shape by laser drilling can have a cross-sectional shape in which the width narrows as it gets deeper. In this case, the inner surface of the processing area can have an inclined surface.

[0119] When a laser beam is shone around the bridge in this manner, the bridge is formed such that its width narrows from one end towards the other in the thickness direction.

[0120] After the bridge formation step (S130), a flexible circuit board structure 10 can be produced in which the flexible circuit board 100 is partially supported on the support substrate 300 by the bridge 500.

[0121] Referring to Figures 7 and 10, the method for manufacturing a flexible circuit board according to one embodiment of the present invention may further include a flexible circuit board separation step (S150). The flexible circuit board separation step (S150) is a step in which the bridge 500 is broken to separate the flexible circuit board 100 from the support substrate 300.

[0122] Figure 13 shows the flexible circuit board 100 separated from the support substrate 300 after the bridge was broken in Figure 10. Referring to Figures 7, 10, and 13, the flexible circuit board 100 separated from the support substrate 300 can be used as a component in various electronic devices.

[0123] As mentioned above, the bridge 500 that supports the flexible circuit board 100 on the support substrate 300 has a shape in which the width narrows from one end to the other in the thickness direction, so it can be easily broken and the flexible circuit board 100 can be easily separated from the support substrate 300.

[0124] On the side surface 101 of the flexible circuit board 100 separated from the support substrate 300, a fractured residue P is formed due to the fracture of the bridge 500. In at least a portion of the fractured residue P, the width of the fractured residue P may be narrowed from one end to the other in the thickness direction (Z-axis direction in Figure 13).

[0125] The protruding length of the fractured residue P remaining on the side surface 101 of the flexible circuit board 100 is shorter than that of conventional bridge fractured residue, which has a constant width in the thickness direction. Therefore, the ease of assembly of the flexible circuit board 100 with electronic devices during use may be improved.

[0126] Furthermore, if the protruding length of the fractured residue P remaining on the side surface 101 of the flexible circuit board 100 is short, the removal work becomes easier and simpler when it is necessary to remove the fractured residue P.

[0127] The flexible circuit board 100 produced by the flexible circuit board manufacturing method according to this embodiment has a shorter protruding length of the fractured remnants P remaining on the side surface 101 of the flexible circuit board 100 compared to the case where a conventional bridge with the same width in the thickness direction breaks. This improves the ease of assembly with electronic devices when using the flexible circuit board 100 and can reduce the defect rate.

[0128] Such a flexible circuit board 100 constitutes part of an electronic device such as a camera module, inductor, or antenna.

[0129] Although embodiments of the present invention have been described, the technical idea of ​​the present invention is not limited by the embodiments presented herein. A skilled expert who understands the technical idea of ​​the present invention can easily propose other embodiments by adding, changing, deleting, or adding components, etc., within the scope of the same technical idea, and this too falls within the scope of the technical idea of ​​the present invention.

Claims

1. At least one flexible circuit board, A support substrate is partially separated from the flexible circuit board by cutting holes that partially surround the side surface of the flexible circuit board, and The flexible circuit board includes at least one bridge that partially connects and supports the support substrate, The bridge is formed such that its width narrows from one end to the other in the thickness direction. Flexible circuit board structure.

2. The aforementioned bridge, It is characterized by being formed extending between the sides of the flexible circuit board and the side of the support board, which face each other with respect to the cutting hole as the axis. The flexible circuit board structure according to claim 1.

3. The cross-section perpendicular to the extension direction of the bridge is triangular or trapezoidal in shape. The flexible circuit board structure according to claim 2.

4. The average extension length of the bridge is 100 μm or less. The flexible circuit board structure according to claim 2.

5. Of the two ends of the bridge in the thickness direction, the width of the relatively narrower short end is 0% or more and 50% or less of the width of the relatively wider long end. The flexible circuit board structure according to claim 1.

6. Of the two ends of the bridge in the thickness direction, the width of the long end having a relatively large width is 60 μm or more and 140 μm or less. The flexible circuit board structure according to claim 1.

7. Of the two ends of the bridge in the thickness direction, the long end having a relatively large width is in contact with one end of the side surface of the flexible circuit board facing the cutting hole in the thickness direction. Of the two ends of the bridge in the thickness direction, the shorter end having a relatively smaller width may or may not be in contact with the other end of the side surface of the flexible circuit board in the thickness direction. The flexible circuit board structure according to claim 1.

8. The thickness of the bridge is 50% to 100% of the thickness of the side surface of the flexible circuit board facing the cutting hole. The flexible circuit board structure according to claim 1.

9. A base substrate generation step involves forming one or more flexible circuit boards with circuit patterns on a base substrate to generate a base substrate, The process includes a bridge forming step of partially cutting the periphery of the flexible circuit board so that the base substrate is divided into the flexible circuit board and the support substrate, thereby forming a bridge that partially supports the flexible circuit board on the support substrate. The bridge is formed such that its width narrows from one end towards the other in the thickness direction. Method for manufacturing flexible circuit boards.

10. In the aforementioned matrix generation step, A circuit pattern is formed in at least one flexible circuit board region provided on the base substrate. The method for manufacturing a flexible circuit board according to claim 9.

11. In the bridge formation step, The periphery of the flexible circuit board formed on the base substrate by laser drilling is cut. The method for manufacturing a flexible circuit board according to claim 9.

12. In the bridge formation step, The laser drilling process is characterized by changing the focus of the laser beam according to the processing depth. The method for manufacturing a flexible circuit board according to claim 11.

13. The process further includes a flexible circuit board separation step of breaking the bridge to separate the flexible circuit board from the support substrate. The method for manufacturing a flexible circuit board according to claim 9.

14. A flexible circuit board separated from the support substrate by the fracture of a bridge connected to the support substrate, On the side surface of the flexible circuit board in contact with the bridge, the remnants of the bridge's fracture are formed. The bridge is characterized in that its width narrows from one end towards the other end in the thickness direction. Flexible circuit board.

15. Including flexible circuit boards, The electronic device according to claim 14.

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