Circuit board processing method and circuit board

Abstract

The application belongs to the technical field of flexible circuit board manufacturing, and discloses a circuit board processing method and a circuit board. The circuit board processing method comprises the following steps: providing a circuit board; performing copper plating treatment on the circuit board to form a pattern, the pattern comprising a circuit area and a non-circuit area; laser drilling to form a groove between the circuit area and the non-circuit area; printing ink to fill the ink into the groove; black hole treatment to make the circuit area conductive; performing copper plating treatment on the circuit area; performing etching treatment on the circuit area and the non-circuit area to expose the bottom copper of the circuit area and the ink; and removing the ink. The circuit board provided by the application is prepared by using the above circuit board processing method. Compared with the traditional processing method of using an etching-resistant layer and exposure alignment, the circuit board processing method provided by the application avoids the change of the line width of the circuit area caused by the refraction of light by the etching-resistant layer, avoids the point-shaped defects or line shortage caused by poor exposure, and improves the production yield.

Description

Technical Field

[0001] This invention relates to the field of flexible circuit board manufacturing technology, and in particular to a circuit board processing method and a circuit board. Background Technology

[0002] Flexible printed circuit boards (FPCBs), commonly known as "flex boards," are highly reliable and extremely flexible printed circuit boards made with polyimide or polyester film as the substrate. They possess numerous advantages that rigid FPCBs lack, such as high wiring density and light weight. In particular, their ability to be freely bent, rolled, and folded allows for flexible arrangement according to spatial requirements, and they can move and stretch freely in three-dimensional space, enabling integrated component assembly and wire connections. Using FPCBs significantly reduces the size of electronic products, meeting the needs of electronic products moving towards higher density, miniaturization, and higher reliability; therefore, FPCBs have found widespread application.

[0003] Conventional flexible circuit boards typically employ subtractive processing techniques to form their circuitry, including CNC drilling, black hole drilling, copper plating, dry film lamination (photoresist layer), exposure, development, etching, and stripping. The achievable linewidth and spacing are closely related to the resolution of the photoresist layer, which in turn depends on the layer thickness. Furthermore, the unavoidable side etching during etching limits the maximum linewidth achievable by subtractive processing to 40μm. In addition, traditional etching methods often result in positive or negative trapezoidal cross-sections of the etched holes, leading to burrs and irregularities in the circuitry. Summary of the Invention

[0004] The purpose of this invention is to provide a circuit board processing method and a circuit board, which solves the problems of positive or inverted trapezoidal lines on the circuit board caused by etching in traditional processing technology, or point-like copper leakage and line shortage caused by poor exposure, aiming to improve the processing accuracy of the line area.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A circuit board manufacturing method, comprising:

[0007] Provide a circuit board;

[0008] The circuit board is copper-plated to form a pattern, which includes circuit areas and non-circuit areas;

[0009] Laser drilling creates a groove between the circuit area and the non-circuit area;

[0010] Printing ink, filling the groove with the ink to cut off the line area and the non-line area;

[0011] The black hole treatment makes the circuit area conductive;

[0012] The circuit area is copper plated.

[0013] The circuit area and the non-circuit area are etched to expose the base copper and ink of the circuit area;

[0014] Remove the ink.

[0015] Optionally, the groove needs to be cleaned after laser drilling and before printing ink.

[0016] Optionally, the ink needs to be baked after the printing ink and before the black hole treatment.

[0017] Optionally, after the baking process and before the black hole treatment, the ink needs to be ground.

[0018] Optionally, after the grinding process and before the black hole treatment, the ink needs to be exposed.

[0019] Optionally, after removing the ink, the electroplating leads used in the copper plating process can be cut or removed using a laser process.

[0020] Optionally, the longitudinal section of the groove is rectangular or square.

[0021] Optionally, an insulating layer needs to be prepared on the circuit board before copper plating is performed to form patterns.

[0022] Optionally, the insulating layer is made of polyimide.

[0023] A circuit board, said circuit board being manufactured using the circuit board processing method described in any of the above embodiments.

[0024] The beneficial effects of this invention are as follows: The circuit board processing method provided by this invention uses laser technology to prepare grooves between the circuit area and the non-circuit area. The extension lines of the grooves prepared by laser are straight, which can effectively reduce the size of the grooves and increase the processing accuracy of the grooves. Moreover, the laser automatically positions the grooves, eliminating alignment deviations and effectively improving the fineness and perpendicularity of the circuits. Ink is printed inside the grooves, and the ink can effectively separate the circuit area and the non-circuit area. After further copper plating in the circuit area, the circuit area and the non-circuit area are etched to expose the bottom copper and ink in the circuit area. Compared with the traditional processing method of alignment by exposure using a photosensitive resist layer, this method avoids changes in the linewidth of the circuit area caused by the refraction of light by the photosensitive resist layer, and avoids dot-like defects or circuit shortages caused by poor exposure, thereby improving production yield.

[0025] The circuit board provided by this invention is manufactured using the circuit board processing method described above. The circuit board has high processing precision in the circuit area and the entire circuit board has good reliability. Attached Figure Description

[0026] Figure 1 This is a flowchart of the circuit board processing method provided in the embodiments of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure after copper plating on the insulating layer provided in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure after a groove is formed between the line area and the non-line area according to an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure after ink is printed inside the groove according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure after copper plating of the circuit area according to an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the structure after etching the circuit area and non-circuit area to expose the bottom copper and ink of the circuit area, according to an embodiment of the present invention.

[0032] Figure 7 This is a schematic diagram of the structure after ink removal provided in an embodiment of the present invention.

[0033] In the picture:

[0034] 100, Insulating layer; 200, Graphic; 210, Circuit area; 220, Non-circuit area; 300, Groove; 400, Ink. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0036] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0039] In existing technologies, the circuits of conventional flexible circuit boards are usually formed using a subtractive process, which includes CNC drilling, black holes, copper plating, application of photosensitive resist layer, exposure, development, etching, and stripping. The line width and spacing achievable by this forming process are closely related to the resolution of the resist layer, which in turn depends on the thickness of the resist layer. In addition, the inevitable side etching phenomenon during etching limits the line width that the subtractive process can achieve to 40μm. Furthermore, traditional etching easily leads to positive or negative trapezoidal cross-sections of the etched holes, which can easily result in burrs and irregularities in the circuitry.

[0040] This embodiment provides a circuit board processing method to solve the problems of positive or inverted trapezoidal lines on the circuit board caused by etching in traditional processing technology, or point-like copper leakage and line shortage caused by poor exposure, aiming to improve the processing accuracy of the line area.

[0041] like Figures 1-7 As shown, the circuit board processing method includes the following steps:

[0042] S1. Provide a circuit board;

[0043] S2. Copper plating is performed on the circuit board to form a pattern 200, which includes a line area 210 and a non-line area 220.

[0044] S3. Laser drilling to form a groove 300 between the line area 210 and the non-line area 220;

[0045] S4. Printing ink 400: Fill the groove 300 with ink 400 to cut off the line area 210 and the non-line area 220.

[0046] S5, black hole treatment, to make the line area 210 conductive;

[0047] S6. Copper plating is performed on the line area 210.

[0048] S7. Etch the line area 210 and the non-line area 220 to expose the bottom copper and ink 400 of the line area 210.

[0049] S8, Remove Ink 400.

[0050] The circuit board processing method provided in this embodiment uses laser technology to prepare a groove 300 between the circuit area 210 and the non-circuit area 220. The extension line of the groove 300 prepared by laser is straight, which can effectively reduce the size of the groove 300 and increase the processing accuracy of the groove 300. Moreover, the laser automatically positions the groove, and there will be no alignment deviation, which effectively improves the fineness and perpendicularity of the circuit. Ink 400 is printed in the groove 300. The ink 400 can effectively cut the circuit area 210 and the non-circuit area 220. After the circuit area 210 is further copper plated, the circuit area 210 and the non-circuit area 220 are etched to expose the bottom copper and ink 400 of the circuit area 210. Compared with the traditional processing method of alignment by exposure through photosensitive resist layer, this method avoids the linewidth of the circuit area 210 caused by the refraction of light by the photosensitive resist layer, and avoids the problem of dot-like defects or circuit shortages caused by poor exposure, thereby improving the production yield.

[0051] In this embodiment, before copper plating is performed on the circuit board to form pattern 200, an insulating layer 100 needs to be prepared on the circuit board. The insulating layer 100 forms the base layer of the circuit board, which can be used to support the copper layer. In multilayer circuit design, it can play an insulating role between circuit layers.

[0052] Furthermore, the insulating layer 100 is made of polyimide, which has good mechanical properties and corrosion resistance. It can provide sufficient support for the copper layer in the line area 210 and the non-line area 220 to improve the reliability of the copper layer.

[0053] Optionally, after laser drilling and before printing ink 400, the groove 300 needs to be cleaned to remove impurity particles, such as laser toner, generated during the laser drilling process, thereby preventing insufficient adhesion between ink 400 and groove 300 when ink 400 is printed in the groove 300 later.

[0054] Optionally, after printing ink 400 and before black hole treatment, ink 400 needs to be baked to solidify ink 400 from a semi-liquid state to a solid state, so as to prevent ink 400 from flowing in or out of the groove 300 and affecting the subsequent copper plating process.

[0055] Furthermore, after baking and before black hole treatment, the ink 400 needs to be ground to remove the ink 400 from the surface of the circuit area 210 and the non-circuit area 220, so as to avoid affecting the subsequent copper plating process and reducing the conductivity of the circuit area 210.

[0056] Furthermore, after the grinding process and before the black hole treatment, the ink 400 needs to be exposed to make the ink 400 resistant to etching, so as to prevent the subsequent etching process from eroding the ink 400.

[0057] Optionally, after removing the ink 400, the electroplating leads used in the copper plating process are cut or removed using a laser process to avoid the presence of the electroplating leads affecting the subsequent processing and manufacturing of the circuit board.

[0058] Preferably, the longitudinal section of the groove 300 is rectangular or square, and those skilled in the art can set the specific depth and shape of the groove 300 according to actual needs.

[0059] This embodiment also provides a circuit board, which is manufactured using the circuit board processing method described above. The circuit board has high processing precision in the line area 210, and the minimum line width can reach 30μm to 35μm. The entire circuit board has good reliability.

[0060] Multiple batches of products were produced using existing circuit board processing methods and the aforementioned circuit board processing methods. The yield rates of different line widths in each batch were compared. The results showed that the yield rate of circuit boards with a line width of 35μm prepared using existing technology was 87.59%, and the yield rate of circuit boards with a line width of 30μm was 80.33%. In contrast, the yield rate of circuit boards with a line width of 35μm prepared using the aforementioned circuit board processing methods was 95.21%, and the yield rate of circuit boards with a line width of 30μm was 94.52%, representing yield improvements of 7.62% and 14.19%, respectively.

[0061] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A circuit board processing method, characterized in that, include: Provide a circuit board; The circuit board is copper plated to form a pattern (200), the pattern (200) including a line area (210) and a non-line area (220); Laser drilling forms a groove (300) between the line area (210) and the non-line area (220); Printing ink (400) is used to fill the groove (300) to cut off the line area (210) and the non-line area (220); The black hole treatment makes the line area (210) conductive; The line area (210) is copper plated. The circuit area (210) and the non-circuit area (220) are etched to expose the base copper of the circuit area (210) and the ink (400); Remove the ink (400).

2. The circuit board processing method according to claim 1, characterized in that, After the laser drilling and before the printing ink (400), the groove (300) needs to be cleaned.

3. The circuit board processing method according to claim 1, characterized in that, After the printing ink (400) and before the black hole treatment, the ink (400) needs to be baked.

4. The circuit board processing method according to claim 3, characterized in that, After the baking process and before the black hole treatment, the ink (400) needs to be ground.

5. The circuit board processing method according to claim 4, characterized in that, After the grinding process and before the black hole treatment, the ink (400) needs to be exposed.

6. The circuit board processing method according to claim 1, characterized in that, After removing the ink (400), the electroplating leads used in the copper plating process are cut or removed using a laser process.

7. The circuit board processing method according to claim 1, characterized in that, The longitudinal section of the groove (300) is rectangular or square.

8. The circuit board processing method according to claim 1, characterized in that, Before copper plating is performed on the circuit board to form a pattern (200), an insulating layer (100) needs to be prepared on the circuit board.

9. The circuit board processing method according to claim 8, characterized in that, The insulating layer (100) is made of polyimide.

10. A circuit board, characterized in that, The circuit board is manufactured using the circuit board processing method as described in any one of claims 1-9.

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