A method for manufacturing a flexible circuit board with high-precision line patterns

Abstract

The application discloses a high-precision line pattern flexible circuit board manufacturing method, which comprises the following steps: taking a double-sided copper-clad plate, manufacturing a gold finger pattern on the front side of the double-sided copper-clad plate, manufacturing a target pattern on the back side of the double-sided copper-clad plate, and forming a pattern plate; performing electroplating gold processing, using the target pattern for alignment, and punching and forming a positioning hole to form a positioning plate; using the target pattern for alignment, manufacturing a line pattern, and forming a line pattern plate; using the formed positioning hole for positioning, punching an outline, and forming a high-precision line pattern flexible circuit board; the gold finger pattern and the target pattern are simultaneously manufactured, the problem that the plate material expands and shrinks due to multiple times of pattern manufacturing is avoided, the problem that the subsequent manufacturing line pattern precision is affected is solved, the problem that the prior art method of manufacturing a gold finger first and then manufacturing a target pattern leads to complex processing is solved; the positioning hole pattern and the target pattern are exposed and aligned, then punched, and then a line pattern is manufactured, the uniformity of the front and back line patterns is effectively ensured, and the line pattern precision is improved.

Description

Technical Field

[0001] This invention relates to the field of flexible circuit board manufacturing, and more particularly to a method for manufacturing a flexible circuit board with high-precision circuit patterns. Background Technology

[0002] In fields such as medical and communications, a common type of flexible circuit board features gold fingers on all four sides in the center of its surface. This type of high-precision flexible circuit board requires a high degree of uniformity in the alignment of the circuit patterns on both the front and back sides to ensure that the signals are transmitted synchronously when the components on the back are soldered and applied.

[0003] Therefore, to meet the high-precision processing requirements of the gold fingers with "four-sided gold coating" on such circuit boards, the common practice is to first design the gold-plated leads reasonably, then design targets on the front and back sides, perform uniform exposure, improve equipment parameters, and then slowly etch to create the circuit pattern.

[0004] However, the above method requires multiple pattern making processes, which can easily lead to board expansion and contraction, resulting in low accuracy when making subsequent circuit patterns. In addition, it has strict requirements for processing technology and has limitations in achieving the desired effect. It cannot fully guarantee high-precision processing results, resulting in a low pass rate for finished circuit boards.

[0005] Therefore, in order to solve the problems mentioned in the background art, there is a need to provide a method for manufacturing flexible circuit boards with high-precision circuit patterns. Summary of the Invention

[0006] This invention aims to address the challenges of high-fidelity signal transmission and ease of processing in existing flexible circuit boards. It proposes a method for manufacturing flexible circuit boards with high-precision circuit patterns, comprising the following steps:

[0007] S10: Take a double-sided copper-clad board, make a gold finger pattern on the front side and a target pattern on the back side to form a graphic board;

[0008] S20: Perform gold finger electroplating on the graphic plate, align it with the target graphic, punch out positioning holes, and form a positioning plate;

[0009] S30: Using the target pattern for alignment, a circuit pattern is created on the positioning plate to form a circuit pattern plate;

[0010] S40: Position the circuit board using the forming positioning hole, and perform forming and punching according to the outline of the circuit pattern board to form the flexible circuit board.

[0011] Furthermore, the process of creating the target pattern on the back side includes etching the area on the front side corresponding to the target pattern.

[0012] Furthermore, the target pattern alignment involves simultaneously aligning the pattern plate from both the front and back sides using the target pattern; aligning the back side using the target pattern; illuminating the target pattern from the back side to form a shadow pattern on the front side, and aligning the front side using the shadow pattern.

[0013] Furthermore, a buffer pattern is provided on the side of the forming positioning hole near the circuit pattern, and the buffer pattern is a circular ring pattern.

[0014] Furthermore, a buffer pattern is provided on the side of the forming positioning hole near the circuit pattern. The buffer pattern is a semi-circular hole ring, and the arc-shaped edge of the semi-circular hole ring is adjacent to the circuit pattern.

[0015] Furthermore, a buffer pattern is provided on the side of the forming positioning hole near the circuit pattern. The buffer pattern is a plurality of concentric ring patterns or a plurality of semi-circular concentric ring patterns arranged outward from the forming positioning hole as the center.

[0016] Furthermore, the gold finger electroplating process includes: applying an anti-electroplating dry film to both sides of the pattern plate to create an anti-electroplating dry film pattern, wherein the anti-electroplating dry film pattern includes an electroplating clamping pattern disposed in the edge region.

[0017] Furthermore, the electroplating leads used to create the gold finger pattern are the copper layer on the front side of the pattern board.

[0018] Furthermore, the center of the target pattern is the etching center, and a first copper ring pattern, a first etched pattern, a second copper ring pattern, and a second etched pattern are arranged in a ring outward from the etching center; the first etched pattern has a number of copper layer connection patterns evenly distributed.

[0019] Furthermore, the straight-line distance between the shaped positioning hole and the circuit pattern is 50 micrometers to 200 micrometers.

[0020] This invention's technical solution simultaneously fabricates the gold finger pattern and the target pattern, avoiding multiple pattern fabrications that could lead to board expansion and contraction affecting the accuracy of subsequent circuit pattern fabrication. Furthermore, the remaining copper on the unpatterned board surface serves as the electroplating leads for the gold fingers, eliminating the need for separate lead fabrication and reducing processing steps. This solves the problem of existing technologies that require electroplating the gold fingers before fabricating the target pattern, resulting in complex processing and poor circuit pattern accuracy. By aligning the positioning hole pattern with the target pattern through exposure before punching, and then fabricating the circuit pattern, the consistency of the front and back circuit patterns is effectively guaranteed, improving the accuracy of the circuit pattern. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the process flow of an embodiment of the present invention;

[0023] Figure 2 This is a front view of the graphic plate according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the back of the graphic plate according to an embodiment of the present invention;

[0025] Figure 4 As an embodiment of the present invention Figure 3 Enlarged planar schematic diagram of the BB region in the diagram;

[0026] Figure 5 This is an embodiment of the present invention. Figure 2 Schematic diagram of the AA section structure;

[0027] Figure 6 This is a plan view of the back of the positioning plate according to an embodiment of the present invention;

[0028] Figure 7 This is a schematic diagram of the back of the circuit pattern board according to an embodiment of the present invention;

[0029] Figure 8 This is an embodiment of the present invention. Figure 7 A schematic diagram of the CC section structure;

[0030] Figure 9 This is a plan view of a circuit board with a hole ring as the buffer pattern according to an embodiment of the present invention;

[0031] Figure 10 This is an embodiment of the present invention. Figure 7 Enlarged planar schematic diagram of the HC region in the diagram;

[0032] Figure 11 This is a planar schematic diagram of a flexible circuit board according to an embodiment of the present invention.

[0033] Explanation of icon numbers:

[0034]

[0035] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that all directional indications (such as up, down, left, right, front, back, inside, outside, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0038] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0039] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0040] Please see Figure 1 , Figure 1 This is a schematic diagram of the process flow according to an embodiment of the present invention.

[0041] The manufacturing process of this invention includes using Figure 1 The implementation of each step in the process will be described below. Figure 1 The process of each step will be explained step by step.

[0042] Please see Figure 2 and Figure 3 , Figure 2 This is a front view of the graphic plate according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the back of the graphic plate according to an embodiment of the present invention.

[0043] Step S10:

[0044] Take a double-sided copper-clad board, and make a gold finger pattern 110 on its front side and a target pattern 120 on its back side to form a pattern board 10. In this embodiment, by using a double-sided copper-clad board and making the gold finger pattern 110 and the target pattern 120 at the same time, the problem of board expansion and contraction caused by making the patterns in stages is avoided, which in turn affects the accuracy of subsequent circuit fabrication.

[0045] Please see Figure 4 and Figure 5 , Figure 4 As an embodiment of the present invention Figure 3 Enlarged planar schematic diagram of the BB region in the diagram; Figure 5 This is an embodiment of the present invention. Figure 3 A schematic diagram of the AA section structure.

[0046] In this embodiment, the target pattern area BB is the area where the target pattern 120 is located. The center of the target pattern 120 is the etching center 1210. The first copper ring pattern 1220, the first etched pattern 1230, the second copper ring pattern 1240 and the second etched pattern 1250 are arranged in a ring shape outward from the etching center 1210. The first etched pattern 1230 has a plurality of copper layer connection patterns 1231 evenly distributed.

[0047] The back-side fabrication of the target pattern 120 in this embodiment also includes etching the area on the front corresponding to the target pattern 120 to form a blank pattern 1260. That is, the blank pattern 1260 formed by etching reduces the thickness of the substrate, providing a substrate base for the target pattern 120 to be able to transmit light when illuminated from the back and form a shadow pattern on the front.

[0048] In this embodiment, the target pattern 120 is aligned simultaneously with the pattern plate 10 from both the front and back sides using the target pattern 120: that is, exposure alignment, the centering function of the alignment lens is used to place the target pattern 120 in the center position, and then the movement of the alignment platform is used to align the upper and lower films with the center of the plate. The target pattern 120 is used for alignment on the back side of the pattern plate 10; then the target pattern 120 is illuminated from the back side, so that a shadow pattern is formed on the front side of the pattern plate, and the shadow pattern is used for alignment on the front side. By identifying the target pattern 120, the alignment accuracy is ensured, providing a manufacturing foundation for the precise processing of subsequent processes using the target pattern 120.

[0049] It is worth noting that, such as Figure 3The target graphic area BB shown above, with the target graphic 120 set on the edge area of ​​the graphic board 10, can clearly and effectively define the processing tool graphic of the circuit board, thereby avoiding problems such as graphic redundancy and disorder that may occur during processing. At the same time, it also helps to improve the accuracy and efficiency of circuit board processing, ensuring the accuracy and consistency of circuit board processing, making the circuit board processing process more efficient and accurate, improving the overall quality and reliability of the circuit board. In addition, the target graphic 120 plays a positioning auxiliary role. Set in the edge area of ​​the board, it is convenient to remove it together when the circuit board is punched and formed later, without affecting the circuit in the middle.

[0050] Please see Figure 6 , Figure 6 This is a schematic diagram of the front planar structure of the positioning plate according to an embodiment of the present invention.

[0051] Step S20:

[0052] The graphic board 10 is electroplated with gold finger pattern 110 to form gold finger 210. The target pattern 120 is used for alignment, and positioning holes 220 are punched to form positioning plate 20. The gold finger 210 requires a four-sided gold-plating process, and the gold finger 210 is located inside the board surface. The electroplating of the gold finger 210 requires electroplating leads for electrical conduction. Therefore, in this embodiment, the electroplating leads used to make the gold finger pattern 120 are the copper layer on the front side of the graphic board 10. That is, by using the other unpatterned front copper layer areas of the double-sided copper-clad board as "electroplating leads", the process of designing electroplating leads separately can be reduced, and the processing accuracy and efficiency of the gold finger 210 can be improved.

[0053] The electroplating process of the gold finger pattern 110 in this embodiment includes: applying an anti-electro ...

[0054] It is worth noting that the anti-electroplating dry film pattern 130 includes an electroplating clamping pattern 1310 disposed in the edge area. Since both sides of the double-sided copper clad laminate are copper layers, there is no need to make a clamping pattern for the electroplating line. The anti-electroplating dry film pattern 130 can directly expose the electroplating clamping pattern 1310, so that the electroplating clamping pattern 1310 forms a connection with the other unpatterned front copper layer areas of the double-sided copper clad laminate, providing a conductive path for the electroplating of the gold finger 210.

[0055] Please see Figure 7 and Figure 8 , Figure 7 This is a schematic diagram of the back structure of the circuit pattern board according to an embodiment of the present invention; Figure 8 This is an embodiment of the present invention. Figure 7 A schematic diagram of the CC section structure.

[0056] Step S30:

[0057] Using the target pattern 120 for alignment, the circuit pattern 310 is made on the positioning plate 20 to form the circuit pattern plate 30. It is worth noting that in the prior art, the circuit pattern 310 is generally made first and then the positioning hole 220 is formed. However, when the positioning hole 220 is formed by punching in the subsequent process, the impact force will pull on the circuit pattern 310 formed earlier, which can easily affect the accuracy of the circuit pattern 310.

[0058] Therefore, this embodiment adopts the method of first making the positioning hole 220 and then making the circuit pattern 310.

[0059] Since the circuit board is a high-precision circuit board, the forming positioning hole 220 needs to be close to the circuit pattern 310. When punching the forming positioning hole 220, there is also a possibility that the nearby circuit pattern 310 may be pulled, causing the adjacent circuit pattern 310 to be bent or deformed. Therefore, the method of making the forming positioning hole 220 first and then making the circuit pattern 310 is adopted. Since the board surface is still a whole copper layer when punching the forming positioning hole 220 and the circuit is not formed, the problem of bending or deforming the circuit pattern can be effectively avoided.

[0060] However, since the positioning holes 220 are made before the circuit pattern 310 is made, during etching, because the positioning holes 220 are already present and are close to the circuit pattern 310, the etching solution sprayed from the front and back can be excessively exchanged through the positioning holes 220, which can easily lead to over-etching of the circuit pattern 310 near the positioning holes 220. Therefore, in this embodiment, a buffer pattern 320 is provided on the side of the positioning hole 220 near the circuit pattern 310. The buffer pattern 320 is a circular pattern. The etching solution is exchanged through the positioning holes 220. The buffer pattern 320 is provided to buffer or block the excessive exchange of etching solution onto the adjacent circuit pattern 310, which could lead to over-etching of the adjacent circuit pattern 310.

[0061] Please see Figure 9 , Figure 9 This is a schematic planar structure diagram of a circuit pattern board with a hole ring as the buffer pattern according to an embodiment of the present invention.

[0062] In one embodiment, the buffer pattern 320 is a pattern of a hole ring 3210. That is, a hole ring 3210 is provided in the forming positioning hole 220. The hole ring 3210 serves to isolate the etching solution. When the etching solution overflows, it will first cover the hole ring 3210, which can reduce the etching solution from contacting the adjacent circuit pattern 310 and avoid etching damage to the circuit pattern 310, which could lead to short circuits in subsequent applications.

[0063] Please continue reading. Figure 7 , Figure 7 This is a schematic diagram of the back structure of the circuit pattern board according to an embodiment of the present invention.

[0064] In one embodiment, a buffer pattern 320 is provided on the side of the forming positioning hole 220 near the circuit pattern 310. The buffer pattern 320 is a semi-circular hole ring (i.e., Figure 7 Although the forming positioning hole 220 is close to the circuit pattern 310, since the circuit pattern 310 is only distributed on one side of the forming positioning hole 220, only half of the hole ring 3210 actually plays a buffering and isolation role. That is, the semi-circular hole ring is located between the forming positioning hole 220 and the circuit pattern 310 in order to isolate the etching solution from the circuit pattern 310. Therefore, a semi-circular hole ring structure with half of the hole ring 3210 can be selected. The arc edge of the semi-circular hole ring faces the circuit pattern 310. Furthermore, the semi-circular hole ring can better release the internal stress of the circuit board and prevent excessive expansion and contraction of the insulating dielectric layer during cleaning and drying processes, which is beneficial to improving the accuracy of circuit processing.

[0065] Please see Figure 10 , Figure 10 This is an embodiment of the present invention. Figure 7 A magnified planar schematic diagram of the HC region. Figure 10 This is a schematic diagram of a planar structure in which the buffer pattern of an embodiment of the present invention is a semi-circular concentric ring.

[0066] In one embodiment, the buffer pattern area HC is a pattern area in which the buffer pattern is a semi-circular concentric ring. A buffer pattern 320 is set on the side of the forming positioning hole 220 near the circuit pattern 310. The buffer pattern 320 is a plurality of concentric ring patterns or a plurality of semi-circular concentric ring patterns 3220 arranged outward from the forming positioning hole 220 as the center. That is, the height difference formed between the plurality of rings forms a "dam" to separate the etching solution in the exchange process layer by layer, so as to prevent the etching solution from contacting the adjacent circuit pattern 310 and causing the circuit pattern 310 to be etched.

[0067] Please see Figure 11 , Figure 11 This is a schematic diagram of the planar structure of a high-precision circuit pattern flexible circuit board according to an embodiment of the present invention.

[0068] Step S40:

[0069] Positioning is achieved using the forming positioning hole 220, and forming and punching are performed according to the outline 330 of the circuit pattern board to form a flexible circuit board 40.

[0070] It is worth noting that, due to the high precision requirements of the circuit board in this embodiment, the design of the molding positioning hole 220 must be close to the circuit pattern 310. However, if the distance is too close, it will also lead to the design space of the buffer pattern 320 being too narrow, which will not play a good role in isolating the etching solution. Therefore, the straight-line distance between the molding positioning hole 220 and the circuit pattern 310 is 50 micrometers to 200 micrometers to meet the manufacturing space of the buffer pattern 320.

[0071] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for manufacturing a flexible circuit board with high-precision circuit patterns, characterized in that, The manufacturing method includes the following steps: S10: Take a double-sided copper-clad board and simultaneously create a gold finger pattern and a target pattern. Create the gold finger pattern on the front side and the target pattern on the back side to form a pattern board. The process of creating the target pattern on the back side includes etching the area on the front side corresponding to the target pattern to form a blank pattern. S20: Perform gold finger electroplating on the graphic plate, align it with the target graphic, punch out positioning holes, and form a positioning plate; The target pattern alignment involves simultaneously aligning the target pattern to the pattern plate from both the front and back sides; aligning the target pattern on the back side; illuminating the target pattern from the back side to create a shadow pattern on the front side, and then aligning the front side using the shadow pattern. S30: Using the target pattern for alignment, a circuit pattern is created on the positioning plate to form a circuit pattern plate; S40: Position the circuit board using the forming positioning hole, and perform forming and punching according to the outline of the circuit pattern board to form the flexible circuit board.

2. The method for manufacturing a flexible circuit board with high-precision circuit patterns as described in claim 1, characterized in that, A buffer pattern, which is a circular ring, is provided on the side of the forming positioning hole near the circuit pattern.

3. The method for manufacturing a flexible circuit board with high-precision circuit patterns as described in claim 1, characterized in that, A buffer pattern is provided on the side of the forming positioning hole close to the circuit pattern. The buffer pattern is a semi-circular hole ring, and the arc edge of the semi-circular hole ring faces the circuit pattern.

4. The method for manufacturing a flexible circuit board with high-precision circuit patterns as described in claim 1, characterized in that, A buffer pattern is provided on the side of the forming positioning hole near the circuit pattern. The buffer pattern is a plurality of concentric ring patterns or a plurality of semi-circular concentric ring patterns arranged outward from the forming positioning hole as the center.

5. The method for manufacturing a flexible circuit board with high-precision circuit patterns as described in claim 1, characterized in that, The gold finger electroplating process includes: applying an anti-electroplating dry film to both sides of the pattern plate to create an anti-electroplating dry film pattern, wherein the anti-electroplating dry film pattern includes an electroplating clamping pattern disposed in the edge region.

6. The method for manufacturing a flexible circuit board with high-precision circuit patterns as described in claim 1, characterized in that, The electroplating leads used to create the gold finger pattern are the copper layer on the front side of the pattern board.

7. The method for manufacturing a flexible circuit board with high-precision circuit patterns as described in claim 1, characterized in that, The target pattern is etched at its center, and a first copper ring pattern, a first etched pattern, a second copper ring pattern, and a second etched pattern are arranged outward from the etched center in a ring shape. The first etched pattern has several copper layer connection patterns evenly distributed.

8. The method for manufacturing a flexible circuit board with high-precision circuit patterns as described in claim 1, characterized in that, The straight-line distance between the shaped positioning hole and the circuit pattern is 50 micrometers to 200 micrometers.

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