Method for removing etching residual copper

Abstract

The invention provides a method for removing etched residual copper. The method comprises the following steps: providing an etched PCB (Printed Circuit Board); the defect identification module is used for comprehensively scanning the PCB and identifying defects on the PCB; performing laser positioning on the defects, and performing laser ablation on the defects; the laser ablation defect is checked through the overhaul camera, and the repair condition of the defect is judged; wherein the PCB after laser ablation is compared with the CMA graph, namely, when the PCB is inconsistent with the CMA graph, the laser camera is switched to carry out laser ablation; when the PCB is consistent with the CMA graph, laser ablation of the defects is completed, the PCB is inspected through the overhaul camera, after laser ablation is conducted on the defects on the PCB, inspection is conducted through the overhaul camera, if no repair defect exists, laser ablation continues to be conducted, and then inspection continues to be conducted through the overhaul camera; therefore, the defects on the PCB can be repaired instead of being overhauled, and the efficiency of processing the defects on the PCB is greatly improved.

Description

Technical Field

[0001] The present application belongs to the technical field of PCB, and in particular to a method for removing etching residual copper. Background Art

[0002] In the prior art, the chemical etching method in traditional FCB manufacturing has problems such as environmental pollution, large edge roughness, and difficulty in meeting the requirements of high-density interconnection (HDI). That is, chemical etching is used to remove unnecessary parts on the copper foil to form a layout of conductive paths and electronic component connections. Ideally, the etching process should completely remove the copper layer that is not protected by the resist, leaving only the circuit pattern required by the design. However, due to various reasons, such as improper etching time control, uneven resist coating, or insufficient etching solution concentration, the copper in some areas may not be completely etched away. The remaining copper is called "etching residual copper".

[0003] Etching residual copper may affect the performance and reliability of PCB, specifically in the following aspects:

[0004] 1. Electrical Shorts: Residual copper traces may cause shorts between parts of a circuit that should not be connected.

[0005] 2. Signal interference: Additional copper may change the electromagnetic characteristics of the circuit, causing signal interference or attenuation.

[0006] 3. Thermal management issues: Excessive copper can affect the thermal conductivity of the PCB.

[0007] 4. Mechanical strength: In some cases, irregular copper residues may weaken the mechanical stability of the PCB.

[0008] If etching residual copper problems are found, the PCB usually needs to be reworked to ensure the quality and function of the product.

[0009] To address the above problems, no effective solution has been proposed yet.

[0010] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0011] The purpose of the present application is to provide a method for removing etching residual copper to solve the problem of various defects occurring after PCB chemical etching.

[0012] The present application provides a method for removing etching residual copper, comprising:

[0013] Provide etched PCB;

[0014] Performing a comprehensive scan on the PCB to identify defects on the PCB;

[0015] performing laser positioning on the defect and laser ablating on the defect;

[0016] Inspecting the defect caused by laser ablation by using a repair camera to determine the repair status of the defect;

[0017] The PCB after laser ablation is compared with the CMA image, that is, when the PCB is inconsistent with the CMA image, the laser camera is switched to perform laser ablation; the PCB and the CMA are compared. Figure 1 When the defect is ablated, laser ablation is completed.

[0018] Preferably, in the step of "comprehensively scanning the PCB", a high-resolution camera is used for scanning.

[0019] Preferably, the defects include short circuit, open circuit and bridge.

[0020] Preferably, in the step of "performing laser positioning on the defect", finely focused laser is used.

[0021] Preferably, the laser power varies with the thickness of the PCB material.

[0022] Preferably, a variable focal length lens is used in the laser positioning and laser ablation steps to automatically adjust the focal position and the spot size.

[0023] Preferably, during the laser positioning and laser ablation steps, a mixture of inert gas and active gas is introduced to accelerate the metal evaporation rate.

[0024] Preferably, after the step of "laser ablating the defects" is completed, the PCB is cleaned by an ultrasonic cleaning and ion wind drying system.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention can repair defects on the PCB by comprehensively scanning, locating and laser ablation repairing the defects on the PCB.

[0027] 2. The present invention uses a maintenance camera to inspect the PCB. After laser ablation of defects on the PCB, the maintenance camera is used for inspection. If the defects are not repaired, laser ablation is continued, and then the maintenance camera is used for inspection. In this way, the defects on the PCB can be turned from inspection to repair, which greatly improves the efficiency of defect processing on the PCB.

[0028] 3. The present invention can introduce a mixture of inert gas and active gas during the steps of laser positioning and laser ablation to accelerate the metal evaporation rate, while reducing the generation of harmful by-products and improving environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0030] Figure 1 It is an overall flow chart of a method for removing etching residual copper provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0032] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "upper", "middle", "lower", "inner", "outer", "front", "back", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. The terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following describes an implementation method of the present invention based on its overall structure.

[0033] Reference Figure 1As shown, an embodiment of the present application provides a method for removing etching residual copper, comprising:

[0034] Provide etched PCB;

[0035] Perform a comprehensive scan of the PCB to identify defects on the PCB;

[0036] Laser positioning of defects and laser ablation of defects;

[0037] The laser ablation defects are inspected by the inspection camera to determine the repair status of the defects;

[0038] Among them, the PCB after laser ablation is compared with the CMA map. That is, when the PCB and CMA maps are inconsistent, the laser camera is switched to perform laser ablation; the PCB and CMA Figure 1 When the laser ablation is completed, the defect is completely ablated.

[0039] In the above process, the PCB is etched, and the defects are repaired after the PCB etching is completed. Specifically, the PCB with defects is firstly fully scanned, so that the defects on the PCB can be accurately observed and analyzed during the full scanning process.

[0040] In the above process, after the defects on the PCB are fully scanned, the defects on the PCB can be further located. In this embodiment, the defects can be located by laser. That is, those skilled in the art can set the laser to guide the position of the defect, so as to accurately locate the defects on the PCB.

[0041] After the defect on the PCB is located by laser, the defect position is laser etched or ablated by laser. It can be understood that this embodiment is to perform laser etching or ablation on the defect by laser, so that the defect position can be repaired.

[0042] After the above laser etching or ablation is completed, technicians in this field can choose to use a maintenance camera to inspect the PCB. Specifically, the PCB after laser ablation is compared with the CMA diagram. That is, when the PCB and CMA diagram are inconsistent, the laser camera is switched to perform laser ablation; the PCB and CMA diagram are Figure 1 When the laser ablation is completed, the defect is completely ablated.

[0043] In summary, through the above process, the defects on the PCB can be fully scanned, located and repaired by laser ablation, so that the defects on the PCB can be repaired.

[0044] It is understandable that in the above process, the technicians in this field use the inspection camera to inspect the PCB. That is, after the defects on the PCB are laser ablated, they are inspected by the inspection camera. If the defects are not repaired, laser ablation is continued, and then the inspection camera is continued. The above process is repeated, so that the defects on the PCB can be inspected and repaired, which greatly improves the efficiency of defect processing on the PCB.

[0045] In an optional implementation, preferably, in the step of "comprehensively scanning the PCB", a high-resolution camera is used for scanning. That is, a high-resolution camera can be used in the process of comprehensively scanning the PCB, so that the PCB can be scanned more accurately. Accurate comprehensive scanning of the PCB can enable defects in the PCB to be accurately identified, thereby improving the efficiency of locating the defects in the next step.

[0046] In the above arrangement, there are defects on the PCB after etching, preferably, the defects include short circuit, open circuit and bridge. That is, during the laser ablation process, the excess conductive material at the short circuit can be ablated or etched, so that the metal bridge causing the short circuit can be removed.

[0047] In the above-mentioned implementation, the skilled person in the art arranges to perform positioning and ablation by laser. Preferably, in the step of "laser positioning the defect", a finely focused laser can be used. In this implementation, the skilled person in the art can use a finely focused laser to significantly improve the accuracy of laser positioning and ablation, thereby improving the yield rate in the PCB production process.

[0048] In an optional embodiment, preferably, the laser power varies with the thickness of the PCB material. That is, in this embodiment, only the thickness of the PCB material can be set. During the laser ablation process, the power of the laser can be changed in real time, so as to adapt to ablation in various situations.

[0049] In the above-mentioned setting, the power of the laser can be adjusted. In this embodiment, preferably, a variable focal length lens can be used in the steps of laser positioning and laser ablation to automatically adjust the focal position and the spot size. That is, in this embodiment, the focal position and the spot size of the laser can be automatically adjusted by the variable focal length lens according to the processing requirements.

[0050] In summary, technicians in this field can set the laser power to change with the thickness of the PCB material and use a variable focal length lens in the laser positioning and laser ablation steps to automatically adjust the focal position and spot size, thereby effectively improving the accuracy of laser repair of defects on PCBs and the efficiency of repairing defects on PCBs.

[0051] It is understandable that harmful gases are generated during the laser ablation process. Preferably, in the laser positioning and laser ablation steps, an inert gas and an active gas mixture can be introduced to accelerate the metal evaporation rate. The aforementioned setting can effectively promote the chemical reaction process, accelerate the metal evaporation rate, and reduce the generation of harmful byproducts, thereby improving environmental friendliness.

[0052] In the above process, after the laser ablation of the PCB is completed, preferably, after the step of "laser ablation of defects" is completed, the PCB is cleaned by an ultrasonic cleaning and ion wind drying system, thereby effectively removing residual metal particles and ensuring the cleanliness and long-term reliability of the circuit board.

[0053] In the above process, after the PCB repair is completed, the PCB is again inspected by AOI (Automated Optical Inspection) to confirm that the short circuit has been successfully repaired and to ensure that no new defects have been introduced during the whole process.

[0054] Although different specific embodiments are mentioned in the content of this application, this application is not limited to the situations described in the industry standards or embodiments, etc. Some industry standards or slightly modified implementation plans based on the implementation of the custom methods or embodiments can also achieve the same, equivalent or similar, or predictable implementation effects after deformation of the above embodiments. The embodiments of data acquisition, processing, output, judgment methods, etc. after these modifications or deformations can still fall within the scope of the optional implementation plans of this application.

[0055] Although the present application has been described through embodiments, those skilled in the art will appreciate that there are many modifications and changes to the present application without departing from the spirit of the present application. It is intended that the attached embodiments include these modifications and changes without departing from the present application.

Claims

1. A method for removing residual copper by etching, characterized in that: include: Provide chemically etched PCBs; Performing a comprehensive scan on the PCB to identify defects on the PCB; performing laser positioning on the defect and laser ablating on the defect; Inspecting the defect caused by laser ablation by using a repair camera to determine the repair status of the defect; The PCB after laser ablation is compared with the CMA image, that is, when the PCB is inconsistent with the CMA image, the laser camera is switched to perform laser ablation; when the PCB is consistent with the CMA image, the defect is completely laser ablated.

2. The method for removing etching residual copper according to claim 1, characterized in that: In the step of "comprehensively scanning the PCB", a high-resolution camera is used for scanning.

3. The method for removing etching residual copper according to claim 1, characterized in that: The defects include short circuits, opens and bridges.

4. The method for removing etching residual copper according to claim 1, characterized in that: In the step of "laser locating the defect", a finely focused laser is used.

5. The method for removing etching residual copper according to claim 4, characterized in that: The laser power varies with the thickness of the PCB material.

6. The method for removing etching residual copper according to claim 1, characterized in that: A variable focal length lens is used in the laser positioning and laser ablation steps to automatically adjust the focus position and the spot size.

7. The method for removing etching residual copper according to claim 1, characterized in that: During the laser positioning and laser ablation steps, an inert gas and an active gas mixture are introduced.

8. The method for removing etching residual copper according to claim 1, characterized in that: After the step of "laser ablating the defect" is completed, the PCB is cleaned by an ultrasonic cleaning and ion air drying system.

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