Copper-chromium alloy foil, method, circuit board and device based on laser reflectivity

Abstract

This application provides a copper-chromium alloy foil, method, circuit board, and apparatus based on laser reflectivity. Before preparing the roughened layer of the copper foil, this application first etches a textured structure in the copper-chromium alloy thin film using a laser etching method to obtain the copper-chromium alloy foil. The textured structure includes multiple main branches and branch branches connecting each main branch. The exposed ends of the main branches and the exposed ends of the branch branches form recessed receiving junctions. The inner diameter of the recessed receiving junction formed at the head end of the main branch is more than twice the inner diameter of the main branch it is connected to, and the inner diameter of the recessed receiving junction formed at the head end of the branch branch is more than twice the inner diameter of the branch branch it is connected to. This solves the problem that the roughened surface causes the copper foil to be fixed in the printed circuit board under stress, leading to deformation of the printed circuit board after long-term use. Furthermore, the poor bonding strength and the tendency for the copper foil to generate internal stress make it prone to breakage when the circuit board is impacted, affecting product performance.

Description

Technical Field

[0001] This application relates to the field of copper foil preparation, specifically to a copper-chromium alloy foil based on laser reflectivity, a method, a circuit board, and an apparatus. Background Technology

[0002] Copper foil is widely used as a metal material in printed circuit boards. With the trend of miniaturization in electronic devices, the requirements are becoming more specific and demanding. The stable fixation of copper foil in printed circuit boards and how to avoid the stress caused by rough surfaces can lead to deformation of the printed circuit board after long-term use. In addition, poor bonding strength can easily generate internal stress in the copper foil, making it easy for the copper foil to break when the circuit board is hit, thus affecting product performance. Therefore, there are shortcomings. Summary of the Invention

[0003] This application provides a copper-chromium alloy foil based on laser reflectivity, a method, a circuit board, and an apparatus, aiming to solve the problems of stable fixation of copper foil in printed circuit boards and how to avoid the copper foil being fixed in the printed circuit board due to roughened surfaces, which would cause the printed circuit board to deform easily after long-term use, and the copper foil would easily generate internal stress due to poor bonding strength, resulting in the copper foil being easy to break when the circuit board is hit, thus affecting product performance.

[0004] This application provides a copper-chromium alloy foil for use on a circuit board, the circuit board comprising a substrate layer, the copper-chromium alloy foil, and a circuit structure layer.

[0005] The copper-chromium alloy foil is etched with a textured structure, which includes multiple main stems and branch stems connecting each main stem. The exposed ends of the main stems and the exposed ends of the branch stems form recessed receiving knots. The inner diameter of the recessed receiving knot formed at the head end of the main stem is more than twice the inner diameter of the main stem to which it is connected, and the inner diameter of the recessed receiving knot formed at the head end of the branch stem is more than twice the inner diameter of the branch stem to which it is connected.

[0006] In an optional embodiment, the inner diameter of the main stem is greater than 6 μm, and the inner diameter of the branch stem is greater than 3 μm, wherein the inner diameters of the main stem and the branch stem are the same or different.

[0007] In an optional embodiment, the depth of the recessed accommodating knot is less than 4 μm.

[0008] In an optional embodiment, if the area of ​​the copper foil is greater than a set threshold, among the plurality of recessed receiving junctions, a connecting portion is formed between two adjacent recessed receiving junctions by laser etching, and the inner diameter of the connecting portion is the average inner diameter of the main trunk or branch trunk corresponding to the two connected recessed receiving junctions.

[0009] This application embodiment also provides a method for preparing copper-chromium alloy foil as described above, comprising: obtaining a copper-chromium alloy thin film by electrolysis; etching the texture structure in the copper-chromium alloy thin film by laser etching to obtain copper-chromium alloy foil; and roughening the surface of the copper-chromium alloy foil on the side with the etched texture structure.

[0010] This application embodiment provides another circuit board, including a circuit board body and at least one electronic component disposed on the circuit board body. The circuit board body includes a first circuit board layer and a second circuit board layer, and a copper-chromium alloy copper foil as described above is bonded between the first circuit board layer and the second circuit board layer.

[0011] This application embodiment provides another circuit device, including a housing and a circuit board as described above, wherein the circuit board is disposed inside the housing.

[0012] Beneficial effects As can be seen from the above technical solution, this application provides a copper-chromium alloy foil, method, circuit board, and apparatus based on laser reflectivity. Before preparing the copper foil roughening layer, this application first etches a textured structure in the copper-chromium alloy thin film using a laser etching method to obtain the copper-chromium alloy foil. The textured structure includes multiple main branches and branch branches connecting each main branch. The exposed ends of the main branches and the exposed ends of the branch branches form recessed receiving junctions. The inner diameter of the recessed receiving junction formed at the head end of the main branch is more than twice the inner diameter of the main branch it is connected to, and the inner diameter of the recessed receiving junction formed at the head end of the branch branch is more than twice the inner diameter of the branch branch it is connected to. In this way, the main branches, branch branches, and recessed receiving junctions work together to form a special buffer structure. When bonding with the insulating layer of the printed circuit board, the insulating layer is compressed and can disperse into this buffer structure, thus preventing the copper foil from deforming during bonding with the insulating layer. This is achieved through points (recessed receiving junctions) and lines (main branches and branch branches). The buffer combination of the (parts) not only forms a more dispersed buffer, but also the recessed receiving junction has a stable positioning function, so that the copper foil and the insulating layer will not shift during the use of the circuit board. Furthermore, this application can solve the problem that the copper foil is fixed in the printed circuit board due to the roughened surface, which causes the printed circuit board to deform easily after long-term use. At the same time, the poor bonding force makes the copper foil prone to internal stress, which makes the copper foil easy to break when the circuit board is hit, affecting the product performance. Before roughening, a dispersed buffer structure is formed. After roughening, the roughened protrusions combine with the insulating layer to "squeeze" the insulating layer. The squeezed-out insulating layer can then enter the texture structure of this application. The squeezed-out part of the insulating layer will not exert a large force on the main structure of the copper foil. Moreover, the buffer combination with recessed points (recessed receiving junctions) and lines (main body and branch body) can absorb some of the stress. Therefore, it can avoid the problem that the copper foil is prone to internal stress and thus easily breaks when the circuit board is hit. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the preparation method of copper-chromium alloy copper foil in the embodiments of this application.

[0015] Figure 2 This is one of the structural schematic diagrams of the copper-chromium alloy copper foil in the embodiments of this application.

[0016] Figure 3 This is the second schematic diagram of the structure of the copper-chromium alloy copper foil in the embodiments of this application. Detailed Implementation

[0017] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0018] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. It should be noted that the anilox roller, manufacturing method, and tempered glass disclosed in this application can be used in the field of display technology, as well as in any field other than display technology; the application fields of the anilox roller, manufacturing method, and tempered glass disclosed in this application are not limited.

[0019] This application provides a method for preparing copper-chromium alloy copper foil, which is used in a circuit board. The circuit board includes a substrate layer, the copper-chromium alloy copper foil, and a circuit structure layer, such as... Figure 1 As shown, the copper-chromium alloy foil includes: S1: obtaining a copper-chromium alloy thin film by electrolysis; S2: etching a textured structure in the copper-chromium alloy thin film by laser etching to obtain the copper-chromium alloy foil, wherein the textured structure includes multiple main branches and branch branches connecting each main branch, the exposed ends of the main branches and the exposed ends of the branch branches form recessed receiving junctions, the inner diameter of the recessed receiving junction formed at the head end of the main branch is more than twice the inner diameter of the main branch connected to it, and the inner diameter of the recessed receiving junction formed at the head end of the branch branch is more than twice the inner diameter of the branch branch connected to it; S3: roughening the surface of the copper-chromium alloy foil on the side where the textured structure is etched.

[0020] This application provides a method for preparing copper-chromium alloy foil. Before preparing the roughening layer of the copper foil, a textured structure is first etched into the copper-chromium alloy thin film using laser etching to obtain the copper-chromium alloy foil. The textured structure includes multiple main branches and branch branches connecting each main branch. The exposed ends of the main branches and the exposed ends of the branch branches form recessed receiving junctions. The inner diameter of the recessed receiving junction formed at the head end of the main branch is more than twice the inner diameter of the main branch it is connected to, and the inner diameter of the recessed receiving junction formed at the head end of the branch branch is more than twice the inner diameter of the branch branch it is connected to. In this way, the main branches, branch branches, and recessed receiving junctions work together to form a special buffer structure. When bonding with the insulating layer of the printed circuit board, the insulating layer is compressed and can disperse into this buffer structure, thus preventing the copper foil from deforming during bonding with the insulating layer. Through the buffer combination of points (recessed receiving junctions) and lines (main branches and branch branches), not only can... The buffer is formed more dispersedly, and the recessed receiving junction also has a stable positioning function, so that the copper foil and the insulating layer will not shift during the use of the circuit board. Furthermore, this application can solve the problem that the copper foil is fixed in the printed circuit board due to the roughened surface, which causes the printed circuit board to deform easily after long-term use. At the same time, the poor bonding force makes the copper foil prone to internal stress, which makes the copper foil easy to break when the circuit board is hit, affecting the product performance. Before roughening, a dispersed buffer structure is formed. After roughening, the roughened protrusions combine with the insulating layer to "squeeze" the insulating layer. The squeezed-out insulating layer can then enter the texture structure of this application. The squeezed-out part of the insulating layer will not exert a large force on the main structure of the copper foil. Moreover, the buffer combination of the recessed points (recessed receiving junctions) and lines (main trunk and branch trunks) can absorb some of the stress. Therefore, it can avoid the problem that the copper foil is prone to internal stress and thus easily breaks when the circuit board is hit.

[0021] Specifically, in an optional embodiment, obtaining a copper-chromium alloy thin film by electrolysis includes: electrolyzing a solution containing copper sulfate and chromium sulfate in an electrolytic cell, wherein the electrolytic cell uses an insoluble material as the anode and a cathode is a cathode that is constantly rotating with its bottom immersed in the copper sulfate and chromium sulfate electrolyte, and copper and chromium in the solution are deposited onto the surface of the cathode roller to form a copper-chromium alloy thin film.

[0022] Specifically, this embodiment describes the specific parameters and steps for depositing a copper-chromium alloy thin film on an anode and a rotating cathode roller made of insoluble materials by electrolysis in a mixed electrolyte of copper sulfate (CuSO4) and chromium sulfate (SnSO4).

[0023] First, prepare the equipment: Electrolytic cell: made of corrosion-resistant stainless steel with an internal insulating layer to prevent short circuits.

[0024] Anode: A square anode made of an insoluble material (such as platinum or titanium) with an area of ​​120 cm².

[0025] Cathode: A roller made of stainless steel or other corrosion-resistant materials, with a diameter of 10cm and a length of 30cm.

[0026] Next, prepare the electrolyte: Solution ratio: Copper sulfate solution: 0.5M, Chromium sulfate solution: 0.2M.

[0027] After mixing, ensure the pH of the solution is maintained between 2 and 3 to improve the uniformity of deposition.

[0028] Next, set the electrolysis parameters: Current density: set to 5 mA / cm² to ensure uniform coating over a large area. Electrolysis time: 6 hours, which can be adjusted according to the required film thickness.

[0029] Temperature control: Maintain the electrolyte temperature at 25±2°C to stabilize the chemical reaction rate.

[0030] Stirring speed: A pump is used to maintain constant stirring of the electrolyte at 300 rpm to improve ion mobility. Electrolysis process: First, the power is turned off, ensuring there is no short circuit between the anode and cathode. Then, the electrolytic cell is filled with the mixed electrolyte. Next, the cathode roller is turned on and rotated at a constant speed (1 rpm) to form a uniform flow layer on the cathode surface, promoting uniform deposition. Finally, the power is turned on, allowing current to flow through the electrolytic cell to begin the electrolysis reaction.

[0031] It should be noted that after electrolysis is completed, the power is turned off, the roller is removed, and it is gently washed with deionized water to remove residual electrolyte. Then, it is dried using a hot air dryer with the temperature set at 60°C for 30 minutes to obtain the electrolyzed copper foil film.

[0032] It should be noted that the electrolysis process in this application can employ existing electrolysis processes, and this application does not impose any restrictions on this. It should also be noted that, in the specific process, this application has discovered through research that copper-chromium alloys have relatively low laser utilization due to their high laser reflectivity. Simultaneously, copper-chromium alloys possess high thermal stability; therefore, by increasing the laser output power, smaller-scale textured structures can be etched. Thus, by combining the material properties, the combination of the main body, branch bodies, and recessed containment junctions in this application has been developed.

[0033] The copper-chromium alloy foil prepared by the above-described process of this application has a chromium content of 0.5-1.2%, high copper-chromium alloy purity, high thermal conductivity, high mechanical strength and wear resistance, tensile strength of 295 MPa, elongation of not less than 6%, thermal conductivity of 290 W / (m℃), hardness of ≥490 HB (Britner hardness), and mass resistivity of not more than 0.183 Ω·g / ㎡. This application will not elaborate on these aspects.

[0034] This application embodiment further provides a copper-chromium alloy copper foil. Specifically, the copper-chromium alloy copper foil is used in a circuit board. The circuit board includes a substrate layer, a copper-chromium alloy copper foil, and a circuit structure layer. A textured structure is etched in the copper-chromium alloy copper foil. The textured structure includes multiple main branches and branch branches connecting each main branch. The exposed ends of the main branches and the exposed ends of the branch branches form recessed receiving junctions. The inner diameter of the recessed receiving junction formed at the head end of the main branch is greater than twice the inner diameter of the main branch to which it is connected. The inner diameter of the recessed receiving junction formed at the head end of the branch branch is greater than twice the inner diameter of the branch branch to which it is connected.

[0035] The following is combined Figure 2 and Figure 3 The above-mentioned texture structure of this application will be described in detail.

[0036] The texture structure includes a plurality of main stems 11 and branch stems 12 connecting each main stem 11. The exposed head ends of the main stems 11 and the exposed head ends of the branch stems 12 form recessed receiving knots 13. The inner diameter of the recessed receiving knot 13 is greater than twice the inner diameter of the main stem 11 or the branch stem 12 connected to it.

[0037] Specifically, such as Figure 2 As shown, this application includes multiple originating points extending in a main and branch manner, gradually distributing across the entire copper foil. It should also be noted that this application… Figure 2 and Figure 3 The example provided is merely an illustration; in reality, the morphological structure may be more complex in form and structure, which will not be elaborated upon in this application.

[0038] In an optional embodiment, the inner diameter of the main stem 11 is greater than 6 μm, and the inner diameter of the branch stem 12 is greater than 3 μm, wherein the inner diameters of the main stem 11 and the branch stem 12 may be the same or different. This provides a more favorable size range for the inner diameters of the main stem 11 and the branch stem 12, which is beneficial for providing a more suitable replacement space.

[0039] It should be noted that the recessed receiving junction 13 of this application further plays a positioning and fixing role. When it is bonded to the insulating layer, the position of the insulating layer and the layer structure of this application can be further restricted by this structure, making it less likely to form misalignment.

[0040] In an optional embodiment, the depth of the recessed accommodating junction 13 is less than 4 μm. This keeps the recess depth within a reasonable range, thus controlling the depth to within 4 μm and preventing the copper foil from breaking more easily due to excessive depth.

[0041] In an optional embodiment, the number of recessed accommodating knots is the sum of the number of the main stems exposed at their heads and the number of the branch stems.

[0042] In an optional embodiment, if the area of ​​the copper foil is greater than a set threshold, a connecting portion 14 is formed between two adjacent recessed receiving junctions 13 by laser etching. The inner diameter of the connecting portion 14 is the average inner diameter of the main trunk 11 or branch trunk 12 to which the two connected recessed receiving junctions 13 are connected. In this embodiment, when S is greater than the set threshold, it indicates that the copper foil area is large. At this time, the distance between the two recessed receiving junctions 13 may be too far. Therefore, the connecting portion 14 is used to connect the relatively far-distance recessed receiving junctions 13, thereby improving the local dispersion uniformity and avoiding the problem of uneven force due to uneven local dispersion when bonding with the insulating layer later. Furthermore, the inner diameter of the connecting portion 14 is the average inner diameter of the main trunk 11 or branch trunk 12 to which the two connected recessed receiving junctions 13 are connected, thereby avoiding the influence of anisotropic differences caused by adding an extra connecting portion 14.

[0043] In an optional embodiment, if the length of the connecting portion 14 is greater than the average connecting portion length, a secondary recessed receiving knot 13 is formed on the corresponding connecting portion. The inner diameter of the secondary recessed receiving knot 13 may be the same as or different from the inner diameter of the recessed receiving knot 13. In this embodiment, if the length of the connecting portion 14 is greater than the average connecting portion length, the number of secondary recessed receiving knots 13 can be increased to improve local uniformity. This application will not elaborate on this aspect.

[0044] In an optional embodiment, the method further includes: passivating the surface of the copper-chromium alloy foil 1 on which the texture structure is etched after roughening.

[0045] In an optional embodiment, the roughening treatment of the side surface of the copper-chromium alloy foil on which the texture structure is etched includes: forming rough protrusions on the side surface of the texture structure by electrolyzing a diluted copper sulfate solution.

[0046] Furthermore, this application also provides a circuit board, including a circuit board body and at least one electronic component disposed on the circuit board body, the circuit board body including a first circuit board layer and a second circuit board layer, wherein a copper-chromium alloy copper foil as described above is bonded between the first circuit board layer and the second circuit board layer.

[0047] Furthermore, this application also provides a circuit device including a housing and a circuit board as described above, the circuit board being disposed inside the housing.

[0048] The circuit device described in this application can be a terminal device, electronic device, etc., and this application does not limit it.

[0049] It should be noted that the copper-chromium alloy copper foil embodiments and manufacturing method embodiments provided in this invention can be referenced to each other. This application does not limit the embodiments in this regard. Any variations that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. Therefore, they will not be elaborated further. The above descriptions are only optional embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for bonding copper-chromium alloy foil to an insulating layer of a printed circuit board, characterized in that, The bonding method includes: before preparing the copper foil roughening layer, etching a textured structure in the copper-chromium alloy foil using a laser etching method; wherein... The copper-chromium alloy foil is etched with a textured structure, which includes multiple main branches and branch branches connecting each main branch. The exposed ends of the main branches and the exposed ends of the branch branches form recessed receiving knots. The inner diameter of the recessed receiving knot formed at the head end of the main branch is greater than twice the inner diameter of the main branch it is connected to, and the inner diameter of the recessed receiving knot formed at the head end of the branch branch is greater than twice the inner diameter of the branch it is connected to; the depth of the recessed receiving knot is less than 4 μm. The number of recessed knots is the sum of the number of main stems exposed at their heads and the number of branch stems; If the area of ​​the copper foil is greater than a set threshold, among the multiple recessed receiving junctions, a connecting part is formed between two adjacent recessed receiving junctions by laser etching. The inner diameter of the connecting part is the average inner diameter of the main body or branch body corresponding to the two connected recessed receiving junctions. The joining method includes: The copper-chromium alloy foil is bonded to the insulating layer of the printed circuit board.

2. The method for bonding copper-chromium alloy foil to the insulating layer of a printed circuit board according to claim 1, characterized in that, The inner diameter of the main stem is greater than 6 μm, and the inner diameter of the branch stem is greater than 3 μm, wherein the inner diameters of the main stem and the branch stem are the same or different.

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