A method for fabricating a circuit board for fiber semiconductor lasers

Abstract

This invention discloses a method for manufacturing a circuit board for fiber optic semiconductor lasers, comprising the following steps: S1. Fabricating a work board: hot-pressing a copper substrate and copper foil together using PP film; S2. Fabricating a circuit pattern using a negative film process; the circuit pattern includes multiple circuit board fabrication areas, each circuit board fabrication area having two spaced-apart copper foil functional blocks; S3. Using laser milling to remove the PP film exposed between the two copper foil functional blocks in each circuit board fabrication area, exposing the copper substrate; S4. Using laser cutting of inner grooves to obtain multiple circuit board semi-finished products, with each row of circuit board semi-finished products retaining uncut portions; S5. Performing an immersion nickel-palladium-gold process on the work board to obtain the finished circuit board; S6. Connecting each row of circuit board semi-finished products into a string using adhesive tape; S7. Using laser cutting of the uncut portions to obtain individual, separate finished circuit boards. This invention enables mass production, improves production efficiency, and reduces costs.

Description

Technical Field

[0001] This invention relates to the field of circuit board manufacturing technology, and in particular to a method for manufacturing a circuit board for fiber semiconductor lasers. Background Technology

[0002] Circuit boards for fiber semiconductor lasers, such as Figure 1 and Figure 2 As shown, the copper block, which is shaped like a concave "U", has conductive parts that connect the live wire, neutral wire, and ground wire respectively (such as...). Figure 1 and Figure 2 (The parts referred to by A, B, and C are respectively). The two conductive functional parts corresponding to the live wire and neutral wire are spaced apart on the upper layer of the copper block, while the conductive functional part corresponding to the ground wire is located on the lower layer of the copper block. An insulating layer (such as...) is provided between the upper and lower layers of the copper block. Figure 1 and Figure 2 (The part referred to by D in the middle). This type of circuit board has a unique structure and small size, with a thickness of more than 3mm. It is difficult to etch and cannot be mass-produced using traditional PCB manufacturing processes, resulting in low production efficiency and high cost. Summary of the Invention

[0003] The purpose of this invention is to provide a method for manufacturing circuit boards for fiber semiconductor lasers, which enables mass production, improves production efficiency, and reduces costs.

[0004] To achieve the above objectives, the present invention provides a method for manufacturing a circuit board for a fiber optic semiconductor laser, comprising the following steps:

[0005] S1. Fabrication of the work board: The copper substrate and copper foil are thermally pressed together using PP adhesive film;

[0006] S2. A circuit pattern is fabricated using a negative film process; wherein, the circuit pattern includes multiple circuit board fabrication areas, the multiple circuit board fabrication areas are arranged in a rectangular array on the work plate, and each circuit board fabrication area has two copper foil functional blocks that are spaced apart.

[0007] S3. Use laser milling to remove the PP film exposed between two copper foil functional blocks in each circuit board fabrication area, exposing the copper substrate;

[0008] S4. According to the required circuit board design shape, use laser cutting to cut the inner groove to obtain multiple connected circuit board semi-finished products. In each row of circuit board semi-finished products, the uncut parts are retained between two adjacent circuit board semi-finished products and between the circuit board semi-finished products and the edge of the working board.

[0009] S5. Perform an electroless nickel-palladium-gold plating process on the workboard after step S4 to obtain multiple interconnected circuit board finished products.

[0010] S6. Use tape to connect each row of semi-finished circuit boards into a string, and stick the tape to the edges of the board on both sides of the work board;

[0011] S7. Using the uncut portion retained in step S4, a single, separate circuit board is obtained;

[0012] S8. Remove the tape to complete the process.

[0013] As a preferred embodiment of the present invention, in step S1, the thickness of the PP film is 0.05 mm, the thickness of the copper foil is 0.5 mm, and the thickness of the copper substrate is 2.5 mm.

[0014] As a preferred embodiment of the present invention, the specific steps of step S2 are as follows:

[0015] S21. Drill tool holes on the edge of the work plate;

[0016] S22. Polish the copper layers on both the top and bottom sides of the work board to remove debris and oxide layers, and smooth the copper surface;

[0017] S23. Apply a photosensitive dry film to both the top and bottom surfaces of the work board;

[0018] S24. After aligning the circuit film with the work board with the dry film, place it in the exposure machine for exposure. Using the principle of "photography", the circuit on the circuit film is transferred to the surface of the copper foil. The unexposed dry film is developed away by the developing solution, thus exposing the copper foil that is not protected by the dry film.

[0019] S25. Use an etching solution to remove the exposed copper foil, exposing the PP adhesive film, and leaving the copper foil protected by the dry film, i.e., the desired circuit pattern;

[0020] S26. Remove the dry film from the non-circuit patterns on the work board to complete the circuit pattern fabrication.

[0021] As a preferred embodiment of the present invention, in the finished circuit board, a PP film with a width of 0.3 mm is retained around the copper foil functional block.

[0022] As a preferred embodiment of the present invention, the step between step S3 and step S4 is further included: engraving laser characters on a copper foil functional block in each of the circuit board fabrication areas, wherein the laser characters in each of the circuit board fabrication areas are unique identification characters.

[0023] As a preferred embodiment of the present invention, the finished circuit board after step S5 has a nickel thickness of 4 μm, a palladium thickness of 0.1 μm, and a gold thickness of not less than 0.2 μm.

[0024] As a preferred embodiment of the present invention, in step S6, the tape is a non-adhesive tape.

[0025] In a preferred embodiment of the present invention, in step S6, the width of the tape is smaller than the width of the finished circuit board.

[0026] The method for fabricating a circuit board for a fiber semiconductor laser provided by this invention has the following advantages compared with the prior art:

[0027] The method for manufacturing circuit boards for fiber semiconductor lasers of the present invention combines a number of key technologies in modern circuit board manufacturing, including hot pressing, negative film processing, laser cutting and chemical gold processing, which enables mass production of circuit boards for fiber semiconductor lasers, improves production efficiency, reduces costs, and ensures the quality and performance of the circuit boards. Attached Figure Description

[0028] Figure 1 This is a front view of a circuit board used in fiber semiconductor lasers;

[0029] Figure 2 It is at Figure 1 A cross-sectional view along the EE direction in the structure shown;

[0030] Figure 3 This is a schematic diagram of the structure after the circuit pattern is fabricated in the method for fabricating a circuit board for a fiber semiconductor laser provided in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram showing the distribution of the laser milling area in the method for manufacturing a circuit board for a fiber semiconductor laser provided in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of laser cutting inner groove and retaining uncut parts in the method of manufacturing circuit board for fiber semiconductor laser provided in the embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the structure in the method for manufacturing a circuit board for a fiber semiconductor laser provided in this embodiment of the invention, in which each row of semi-finished circuit board is connected into a string using tape. Detailed Implementation

[0034] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0035] like Figures 1 to 6 As shown in the figure, an embodiment of the present invention provides a method for manufacturing a circuit board for a fiber semiconductor laser, which includes the following steps:

[0036] S1. Fabrication of the working board: The copper substrate 1 and copper foil 2 are hot-pressed together using a PP adhesive film 3; wherein the thickness of the PP adhesive film 3 is 0.05mm, the thickness of the copper foil 2 is 0.5mm, and the thickness of the copper substrate 1 is 2.5mm. This step involves the PP hot-pressing and hot-melting method, which achieves a high-strength, durable, stable, immersion-resistant, and acid and alkali-resistant bonding effect by heating the adhesive film to achieve this.

[0037] S2. Use negative film processing to create circuit patterns (such as...) Figure 3 (as shown); wherein, the circuit pattern includes multiple circuit board fabrication areas, the multiple circuit board fabrication areas are arranged in a rectangular array on the work board, and each circuit board fabrication area has two copper foil functional blocks 21 that are spaced apart (i.e., two conductive functional parts A and B that are respectively connected to the live wire and the neutral wire in the technical background).

[0038] The specific steps of step S2 are as follows:

[0039] S21. Drill tool holes 4 on the edge of the work plate; these tool holes will be used to position the work plate in subsequent processes.

[0040] S22. Polish the copper layers on both the top and bottom sides of the work board to remove debris and oxide layers, and smooth the copper surface;

[0041] S23. Apply a photosensitive dry film to both the top and bottom surfaces of the work board;

[0042] S24. After aligning the circuit film with the work board with the dry film, place it in the exposure machine for exposure. Using the principle of "photography", the circuit on the circuit film is transferred to the surface of one side of the copper foil 2. The unexposed dry film is developed away by the developing solution, thereby exposing the copper foil 2 that is not protected by the dry film.

[0043] S25. Use an etching solution (usually an acidic solution) to remove the exposed copper foil 2, exposing the PP film 3, and leaving the copper foil 2 protected by the dry film, which is the desired circuit pattern;

[0044] S26. Remove the dry film from the non-circuit patterns on the work board to complete the circuit pattern fabrication.

[0045] S3. Use laser milling to remove the area exposed between two copper foil functional blocks in each circuit board fabrication area (e.g., ...). Figure 4 The PP film 3 (the part indicated by F in the middle) exposes the copper substrate 1 (i.e., the conductive functional part C connected to the ground line in the background of the art);

[0046] The specific steps of step S3 are as follows:

[0047] S31. First, based on the circuit board design drawings, CAD software is needed to design the path where the PP film 3 needs to be milled (e.g., ...). Figure 4 (as shown); then, the designed path is imported into the control system of the laser milling machine and programmed to ensure that the laser milling machine can perform precise milling according to the predetermined path;

[0048] S32. Based on the material properties of PP film 3 and milling requirements, set the parameters of the laser milling machine, including laser power, cutting speed, focal length, etc.

[0049] S33. Start the laser milling machine. The laser beam mills on the work plate according to the preset path. The laser beam removes the material in the designated area by evaporation or melting, thereby exposing the copper substrate 1.

[0050] S4. Based on the required circuit board design shape, use laser cutting to cut the inner groove (e.g., Figure 5 The hollowed-out area (as indicated by G) yields multiple interconnected circuit board semi-finished products. Within each row of circuit board semi-finished products, uncut portions are retained between adjacent circuit board semi-finished products and between the circuit board semi-finished product and the edge of the working board (e.g., ...). Figure 5 (The part indicated by H in the middle);

[0051] The specific steps of step S4 are as follows:

[0052] S41. First, based on the circuit board design drawings, the inner groove cutting path needs to be designed using CAD software; then, the designed path is imported into the control system of the laser cutting machine and programmed to ensure that the laser cutting machine can cut accurately according to the predetermined path.

[0053] S42. Based on the characteristics of the materials (such as copper substrate 1, PP film 3, etc.) and the cutting requirements, set the parameters of the laser cutting machine, including laser power, cutting speed, focal length, etc.

[0054] S43. Start the laser cutting machine. The laser beam cuts on the work plate according to the preset path. The laser beam removes the material in the designated area by evaporation or melting to form an inner groove.

[0055] During the cutting process, it is necessary to preserve the connection points between each row of semi-finished circuit boards, as well as the connection points between the semi-finished circuit boards and the edge of the work board. These uncut parts ensure that the semi-finished circuit boards can remain connected in subsequent processes, such as immersion nickel-palladium gold plating and tape application, facilitating batch processing.

[0056] S5. Perform an electroless nickel-palladium-gold plating process on the workboard after step S4 to obtain multiple interconnected circuit board finished products.

[0057] It should be noted that the immersion nickel-palladium-gold process generally includes degreasing, micro-etching, pickling, pre-immersion, palladium activation, electroless nickel plating (reduction), electroless palladium plating (reduction), and electroless gold plating (displacement). This process ultimately forms a stable nickel-palladium alloy layer on the copper surface. This alloy layer possesses excellent wear resistance, corrosion resistance, and anti-discoloration properties, effectively protecting the metal surface from environmental influences. Furthermore, the surface treated with this process is exceptionally smooth. This smoothness improves electrical conductivity and signal transmission, while reducing surface reflection and scattering, thus contributing to enhanced performance and reliability of electronic products.

[0058] In this embodiment, the finished circuit board after step S5 has a nickel thickness of 4 μm, a palladium thickness of 0.1 μm, and a gold thickness of not less than 0.2 μm.

[0059] S6. Use tape 5 to connect each row of semi-finished circuit boards into a string, and stick tape 5 to the edges of both sides of the work board, such as... Figure 6 As shown; wherein, the tape 5 is preferably a non-adhesive tape to prevent adhesive residue from being left on the semi-finished circuit board when the tape 5 is subsequently removed; the width of the tape 5 is smaller than the width of the finished circuit board to avoid the tape covering the uncut portion retained in step S4.

[0060] S7. Using the uncut portion retained in step S4, a single, separate circuit board is obtained;

[0061] S8. Remove the tape to complete the process.

[0062] For example, in the finished circuit board, a PP film 3 with a width of 0.3 mm is retained around the copper foil functional blocks to ensure the insulation between the two copper foil functional blocks and the copper substrate 1.

[0063] For example, between step S3 and step S4, the following step is also included: engraving laser characters on a copper foil functional block in each of the circuit board manufacturing areas, and the laser characters in each of the circuit board manufacturing areas are unique identification characters to facilitate subsequent identification and traceability.

[0064] In summary, the method for manufacturing a circuit board for fiber semiconductor lasers provided by this invention combines several key technologies in modern circuit board manufacturing, including hot pressing, negative film processing, laser cutting, and electroless gold processing. This method enables mass production of circuit boards for fiber semiconductor lasers, improves production efficiency, reduces costs, and ensures the quality and performance of the circuit boards.

[0065] In this specification, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for fabricating a circuit board for a fiber semiconductor laser, characterized in that, Includes the following steps: S1. Fabrication of the work board: The copper substrate and copper foil are thermally pressed together using PP adhesive film; S2. A circuit pattern is fabricated using a negative film process; wherein, the circuit pattern includes multiple circuit board fabrication areas, the multiple circuit board fabrication areas are arranged in a rectangular array on the work plate, and each circuit board fabrication area has two copper foil functional blocks that are spaced apart. S3. Use laser milling to remove the PP film exposed between two copper foil functional blocks in each circuit board fabrication area, exposing the copper substrate; S4. According to the required circuit board design shape, use laser cutting to cut the inner groove to obtain multiple connected circuit board semi-finished products. In each row of circuit board semi-finished products, the uncut parts are retained between two adjacent circuit board semi-finished products and between the circuit board semi-finished products and the edge of the working board. S5. Perform an electroless nickel-palladium-gold plating process on the workboard after step S4 to obtain multiple interconnected circuit board finished products. S6. Use tape to connect each row of semi-finished circuit boards into a string, and stick the tape to the edges of the board on both sides of the work board; S7. Using the uncut portion retained in step S4, a single, separate circuit board is obtained; S8. Remove the tape to complete the process.

2. The method for fabricating a circuit board for a fiber semiconductor laser according to claim 1, characterized in that, In step S1, the thickness of the PP film is 0.05 mm, the thickness of the copper foil is 0.5 mm, and the thickness of the copper substrate is 2.5 mm.

3. The method for fabricating a circuit board for a fiber semiconductor laser according to claim 1, characterized in that, The specific steps of step S2 are as follows: S21. Drill tool holes on the edge of the work plate; S22. Polish the copper layers on both the top and bottom sides of the work board to remove debris and oxide layers, and smooth the copper surface; S23. Apply a photosensitive dry film to both the top and bottom surfaces of the work board; S24. After aligning the circuit film with the work board with the dry film, place it in the exposure machine for exposure. Using the principle of "photography", the circuit on the circuit film is transferred to the surface of the copper foil. The unexposed dry film is developed away by the developing solution, thus exposing the copper foil that is not protected by the dry film. S25. Use an etching solution to remove the exposed copper foil, exposing the PP adhesive film, and leaving the copper foil protected by the dry film, i.e., the desired circuit pattern; S26. Remove the dry film from the non-circuit patterns on the work board to complete the circuit pattern fabrication.

4. The method for fabricating a circuit board for a fiber semiconductor laser according to claim 1, characterized in that, In the finished circuit board, a PP film with a width of 0.3mm is retained around the copper foil functional block.

5. The method for fabricating a circuit board for a fiber semiconductor laser according to claim 1, characterized in that, Between step S3 and step S4, the following step is also included: engraving laser characters on a copper foil functional block in each of the circuit board fabrication areas, and the laser characters in each of the circuit board fabrication areas are unique identification characters.

6. The method for fabricating a circuit board for a fiber semiconductor laser according to claim 1, characterized in that, The finished circuit board after step S5 has a nickel thickness of 4 μm, a palladium thickness of 0.1 μm, and a gold thickness of not less than 0.2 μm.

7. The method for fabricating a circuit board for a fiber semiconductor laser according to claim 1, characterized in that, In step S6, the tape is a non-adhesive tape.

8. The method for fabricating a circuit board for a fiber semiconductor laser according to claim 1, characterized in that, In step S6, the width of the tape is smaller than the width of the finished circuit board.

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