Curved surface substrate laser confinement cleaning system and method

Abstract

The invention belongs to the technical field of laser processing, and particularly relates to a curved-surface substrate laser confinement cleaning system and method. The system comprises a control system, a three-dimensional motion platform, a laser and a laser focusing unit, wherein a curved-surface substrate of a metal pattern to be cleaned is fixed on the three-dimensional motion platform; the visual auxiliary positioning system is used for recognizing the space posture of the cleaning area and is electrically connected with the control system. And the control system generates a CAD model and a cleaning path based on an identification result, and cooperatively controls the three-dimensional motion platform and the laser, so that the laser incidence direction is kept within the range of + / -5 degrees of the normal of the target point, and confinement cleaning of the curved surface metal pattern is realized. According to the method, an intelligent reverse decision model of'performance deviation-trimming quantity-laser parameters' is further established, deviation of actually measured electromagnetic performance and a design target is used as input, the material removal quantity and the laser parameters are automatically solved, and closed-loop control of performance diagnosis and trimming machining is formed. The method has the advantages of high-precision positioning, normal incidence control, curvature adaptive compensation and performance-oriented intelligent trimming, and is suitable for high-precision and low-damage local metal removal of LTCC substrates and array plane microstrip lines.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of laser beam processing, and particularly relates to a curved substrate laser limited cleaning system and method. BACKGROUND

[0002] With the continuous development of high-frequency communication, radar systems, aerospace and 5G millimeter wave technologies, low-temperature co-fired ceramic (LTCC) substrates and array microstrip structures have been widely used in radio frequency / microwave devices, antenna arrays and high-density modules due to their excellent dielectric properties, thermal stability and three-dimensional packaging integration capabilities. In these devices, the substrate surface is usually designed with metal patterns such as gold, copper or silver, which are used to achieve conductive interconnection, electromagnetic matching and signal transmission functions. However, during the manufacturing, debugging, repair or structural adjustment of the device, the metal pattern in a specific area often needs to be removed in a limited area to meet the needs of functional reconstruction, defect removal or local circuit modification.

[0003] At present, common methods for removing local metal patterns include manual scribing, wet etching and laser cleaning, but these technologies have obvious shortcomings in curved substrate scenarios. First, the manual scribing method relies heavily on the experience of the operator, making it difficult to ensure the consistency of the removal position and boundary, with low positioning accuracy and easy damage to the substrate. Second, the wet etching technique relies on mask making and chemical corrosion, which is difficult to adapt to changes in spatial curvature, and has the problems of complex process, over-etching or incomplete cleaning. Third, traditional laser cleaning often uses nanosecond lasers for large-area planar scanning, which is difficult to achieve dynamic focusing and limited control on complex curved surfaces, and is prone to edge melting, heat diffusion and substrate damage.

[0004] In summary, existing metal pattern removal techniques have been relatively mature in planar structures, but in the case of LTCC substrates and array microstrip structures with three-dimensional spatial curvature, it is still difficult to meet the needs of high positioning accuracy, edge clarity and limited cleaning without thermal damage to the substrate. In addition, existing technologies generally lack intelligent adjustment means based on electrical performance feedback, and the cleaning process is usually disconnected from the target electrical performance, resulting in deviations between the processing results and design indicators, making it difficult to achieve performance-driven precise adjustment and closed-loop optimization. SUMMARY

[0005] To solve the above-mentioned problems existing in the prior art, the purpose of the present application is to provide a curved substrate laser limited cleaning system and method, which has high-precision spatial positioning capability, laser normal incidence control and adaptive curvature compensation capability, and further realizes closed-loop intelligent adjustment based on electrical performance feedback.

[0006] The technical solution adopted by the present application is: The curved substrate laser limited cleaning system comprises a control system and a three-dimensional motion platform electrically connected with the control system, a curved substrate with a metal pattern to be cleaned is fixed on the three-dimensional motion platform, the control system is electrically connected with a laser, and the output end of the laser is provided with a laser focusing unit corresponding to the curved substrate; a visual auxiliary positioning system for identifying the spatial posture of the metal pattern to be cleaned is further provided, and the visual auxiliary positioning system is electrically connected with the control system; the control system is further electrically connected with an intelligent reverse decision module for receiving the deviation of the measured electromagnetic performance of the curved substrate from the design target, automatically generating the corresponding material removal position, removal amount and laser cleaning parameters, and realizing closed-loop control from performance diagnosis to adjustment processing.

[0007] The control system first acquires the spatial posture (surface three-dimensional point cloud data) of the metal pattern to be cleaned through the visual recognition module, converts the spatial posture into a CAD model, and then generates a cleaning path through the CAD model. The control system dynamically adjusts the position of the laser on the curved substrate by controlling the three-dimensional motion platform, thereby realizing accurate removal of the local metal pattern on the surface of the curved substrate, and realizing limited processing on any specified area with high positioning accuracy and controllable cleaning range. The application can dynamically adjust the laser incidence angle and the three-dimensional motion platform angle, so that the laser always maintains a nearly vertical direction with the normal direction of the scanning position of the metal pattern to be cleaned, ensuring the focusing accuracy and energy uniformity.

[0008] The application introduces an intelligent reverse decision model of performance deviation-adjustment amount-laser parameter, directly couples the cleaning process with the target electrical performance, realizes closed-loop optimization of performance feedback and process parameters, and significantly improves the consistency and efficiency of electrical performance adjustment.

[0009] As a preferred scheme of the application, the laser focusing unit comprises a mirror group and a scanning galvanometer system, and the laser emitted from the laser passes through the mirror group and the scanning galvanometer system in sequence before reaching the surface of the curved substrate.

[0010] As a preferred scheme of the application, the laser is a femtosecond laser or a picosecond laser, and the pulse width of the laser is less than 10 ps. The application uses femtosecond / picosecond laser, which can effectively suppress heat diffusion and is significantly superior to nanosecond laser cleaning, with a very small laser heat affected zone and good substrate protection effect.

[0011] As a preferred scheme of the application, the wavelength of the laser emitted by the laser is 780 nm or 1040 nm, the laser pulse energy is 10-30 muJ, the laser repetition frequency is 100 kHz-1 MHz, and the laser average power is 8-10 W. The laser spot is controlled accurately and the energy density is uniform, which is suitable for high-consistency batch process.

[0012] As a preferred scheme of the present application, the metal pattern to be cleaned on the curved substrate is a gold plating layer with a thickness of 0.5-5 μm, or a copper layer, a silver layer or a copper-silver alloy layer with a thickness of 5-20 μm. The present application is suitable for metal patterns of gold, copper, silver and the like, is compatible with different substrates such as LTCC, ceramic and glass, and meets the needs of various high-end electronic packaging scenarios.

[0013] The laser limited cleaning method for a curved substrate comprises the following steps: S1: fixing a curved substrate with a metal pattern to be cleaned on a three-dimensional motion platform; S2: recognizing the spatial pose of a target area through a vision-assisted positioning system, converting the spatial pose into a CAD model, and generating a cleaning path through the CAD model; S3: controlling the laser to start, and controlling the three-dimensional motion platform pose according to the cleaning path so that the laser cleans the metal pattern to be cleaned along the cleaning path; dynamically adjusting the laser incidence angle and the three-dimensional motion platform angle so that the laser incidence direction is controlled within ±5° of the normal direction of the metal pattern target point; S4: after the laser cleaning is completed, removing residues and performing surface treatment on the cleaning area through a gas blowing device and / or a vacuum cleaning device; S5: testing the electromagnetic performance of the cleaned curved substrate, inputting the test result into an intelligent reverse decision module, automatically generating tuning parameters according to the performance deviation, repeating steps S3 and S4 until the electrical performance meets the preset target.

[0014] As a preferred scheme of the present application, the following steps are further included: S6: cleaning the cleaning area through an ultrasonic device for 5-10 min.

[0015] As a preferred scheme of the present application, the following steps are further included: S7: evaluating the processing area through an optical microscope and a laser confocal curved substrate topography.

[0016] As a preferred scheme of the present application, in step S2, the cleaning path is composed of contour-guided scanning and internal filling scanning, and the adjacent scanning line overlap rate is 70%-90%.

[0017] As a preferred scheme of the present application, in step S3, the laser scanning speed is 50-200 mm / s, and the laser spot diameter is 10-30 μm.

[0018] The present application has the following beneficial effects: The control system of the present application first acquires the spatial posture of the metal pattern to be cleaned through the visual recognition module, converts the spatial posture into a CAD model, and then generates a cleaning path through the CAD model. The control system dynamically adjusts the position of the laser on the curved substrate by controlling the three-dimensional motion platform, thereby realizing the accurate removal of the local metal pattern on the surface of the curved substrate, and can realize limited processing of any specified area with high positioning accuracy and controllable cleaning range. The present application can dynamically adjust the laser incidence angle and the three-dimensional motion platform angle, so that the laser always maintains a nearly vertical direction with the normal direction of the scanning position of the metal pattern to be cleaned, ensuring the focusing accuracy and energy uniformity. The present application introduces an intelligent reverse decision model of performance deviation-adjustment amount-laser parameter, so that the cleaning process is directly coupled with the target electrical performance, realizing the closed-loop optimization of performance feedback and process parameters, thereby significantly improving the consistency and efficiency of electrical performance adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural schematic diagram of the present application; Figure 2 is a structural schematic diagram of the curved substrate.

[0020] In the figure: 1-control system; 2-laser; 3-laser; 4-reflection mirror group; 5-scanning galvanometer system; 6-curved substrate; 7-three-dimensional motion platform. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0023] The present application is dedicated to non-contact and non-thermal damage removal of the local metal conductive pattern in the above-mentioned curved substrate, in order to meet the fine structure adjustment or fault repair needs in high-frequency microwave circuits, radio frequency devices and antenna array modules. The present application is specially used for local removal of metal patterns in low-temperature co-fired ceramic (LTCC) and array microstrip structures, and realizes closed-loop adjustment driven by electrical performance in combination with an intelligent reverse decision module.

[0024] As shown in Figure 1 and Figure 2 The curved substrate laser limited cleaning system of the embodiment, as shown in the figure, comprises a control system 1 and a three-dimensional motion platform 7 electrically connected with the control system 1, a curved substrate 6 with a metal pattern to be cleaned is fixed on the three-dimensional motion platform 7, the control system 1 is electrically connected with a laser 2, the output end of the laser 2 is provided with a laser focusing unit, and the laser focusing unit is arranged corresponding to the curved substrate 6; further comprising a visual auxiliary positioning system for identifying the spatial pose of the metal pattern to be cleaned, the visual auxiliary positioning system is electrically connected with the control system 1, and an intelligent reverse decision module electrically connected with the control system 1, the intelligent reverse decision module is used for dynamically outputting adjustment parameters according to the electrical performance deviation.

[0025] The control system 1 of the present application first acquires the spatial pose of the metal pattern to be cleaned through the visual recognition module, converts the spatial pose into a CAD model, and then generates a cleaning path through the CAD model. The control system 1 dynamically adjusts the position of the laser 3 on the curved substrate 6 by controlling the three-dimensional motion platform 7, thereby realizing the accurate removal of the local metal pattern on the surface of the curved substrate 6, and realizing the limited processing of any specified area with high positioning accuracy and controllable cleaning range. After cleaning, the system tests the electromagnetic performance of the curved substrate, the test results are input into the intelligent reverse decision module, the module calculates the required removal amount and laser parameters, and the cleaning is driven again to realize the closed-loop control of performance feedback and process adjustment. The present application can dynamically adjust the incident angle of the laser 3 and the angle of the three-dimensional motion platform 7, so that the laser 3 always maintains a nearly vertical direction with the normal direction of the scanning position of the metal pattern to be cleaned, ensuring the focusing accuracy and energy uniformity.

[0026] The present application is suitable for non-thermal damage peeling of conductive patterns with a thickness of less than 5 μm, and has the ability of self-adaptive focusing and synchronous path fitting for different curvature radius structures, which is one of the key processes to realize the fine manufacturing and maintenance of millimeter wave and high frequency microwave modules.

[0027] Specifically, the laser focusing unit comprises a mirror group 4 and a scanning galvanometer system 5, and the mirror group 4 comprises two mirrors. The laser 3 beam is reflected by the two mirrors in turn to adjust the direction of the light path, and then enters the scanning galvanometer assembly system. The scanning galvanometer system 5 is used for dynamic deflection and precise focusing of the laser 3, so that it accurately acts on the metal pattern area to be cleaned of the curved substrate 6.

[0028] The laser 2 is a femtosecond laser 2 or a picosecond laser 2, and the pulse width of the laser 2 is less than 10 ps. The present application uses femtosecond / picosecond laser 3, which can effectively suppress heat diffusion and is significantly superior to nanosecond laser 3 cleaning, and the thermal influence area of the laser 3 is extremely small, and the substrate protection effect is good.

[0029] The wavelength of the laser 2 emitting the laser 3 is 780 nm or 1040 nm, the pulse energy of the laser 3 is set to 10-30 muJ, the repetition frequency of the laser 3 is 100 kHz-1 MHz, and the average power of the laser 3 is 8-10 W. The laser 3 spot is controlled accurately and the energy density is uniform, which is suitable for high consistency batch process.

[0030] The metal pattern to be cleaned on the curved substrate 6 is a gold plating layer with a thickness of 0.5-5 mu m, or a copper layer, a silver layer or a copper-silver alloy layer with a thickness of 5-20 mu m. The present application is suitable for metal patterns of gold, copper, silver, etc., is compatible with different substrates such as LTCC, ceramic, glass, etc., and meets the needs of various high-end electronic packaging scenarios.

[0031] The curved substrate laser limited cleaning method of the present embodiment comprises the following steps: S1: fixing the curved substrate 6 with a metal pattern to be cleaned on a three-dimensional motion platform 7; S2: recognizing the spatial pose of the target area through a vision-assisted positioning system, converting the spatial pose into a CAD model, and then generating a cleaning path through the CAD model; The cleaning path is composed of contour-guided scanning and internal filling scanning, and the overlapping rate of adjacent scanning lines is 70%-90%; S3: controlling the laser 2 to start by the control system 1, and controlling the three-dimensional motion platform 7 pose by the control system 1 according to the cleaning path, so that the laser 3 cleans the metal pattern to be cleaned along the cleaning path; dynamically adjusting the laser 3 incident angle and the three-dimensional motion platform 7 angle, so that the laser 3 incident direction is controlled within the range of ±5° of the normal direction of the metal pattern target point; The scanning speed of the laser 3 is 50-200 mm / s, and the laser 3 spot diameter is 10-30 mu m; S4: after the laser 3 cleaning is completed, the residue in the cleaning area is removed and the surface is treated through a gas blowing device and / or a vacuum cleaning device; S5: testing the electromagnetic performance of the cleaned curved substrate 6, inputting the test results into an intelligent reverse decision module, generating tuning parameters according to the performance deviation, and repeating steps S3 and S4 until the electrical performance meets the preset target; S6: cleaning the cleaning area by an ultrasonic device for 5-10 min.

[0032] S7: evaluating the processing area by optical microscopy and laser 3 confocal curved substrate 6 topography.

[0033] Embodiment: The projection length of the curved substrate 6 is 200 pm; the thickness of the partial metal pattern formed on the surface of the curved substrate 6 is about 2 pm, and the projection length is 200 pm. First, the complete curved coordinate data (spatial pose) of the metal pattern to be cleaned is obtained by three-dimensional structured light or laser 3 triangulation of the visual auxiliary positioning system, and then the spatial pose is converted into a CAD model, and the cleaning path is generated through the CAD model. The cleaning system adopts a five-axis linkage mode, in which XYZ is a planar compensation, and the rotation angle is realized by the cooperation of the inclination of the three-dimensional motion platform 7 and the scanning deflection of the laser 3, so as to ensure that the focusing direction of the laser 3 is always controlled within ±5° of the normal direction of the target point. After cleaning, the electromagnetic performance of the curved substrate is tested, and if the S parameter or resonance frequency deviates from the target value, the intelligent reverse decision module automatically calculates the material thickness and laser parameters to be removed, and the driving system performs secondary cleaning to realize the iterative adjustment of performance-driven. The sampling frequency is 1 MHz during cleaning, and the unit energy density is controlled at 0.6 J / cm2. Three scanning paths are superimposed to ensure that the removal depth is stable within the metal layer thickness range, and the edge roughness Ra is controlled below 150 nm.

[0034] The laser limited cleaning method of the curved substrate 6 is as follows: First step: install the curved substrate 6 to be cleaned on the three-dimensional motion platform 7, and adjust the three-dimensional motion platform 7 to make the metal pattern target cleaning area basically perpendicular to the incident direction of the laser 3. In order to adapt to the curvature of the curved substrate 6, an automatic focusing control module is introduced to adjust the focal point Z axis position in real time, so as to ensure the effective focusing of the laser 3 on the curved substrate 6.

[0035] Second step: the selected laser 3 source is a femtosecond laser 2 (Yb-based fiber laser 2) with pulse width <300 fs, working wavelength 1040 nm, pulse repetition frequency set to 500 kHz, single pulse energy set to 20 pJ, and average output power not higher than 10 W. The focusing system adopts f-theta field lens, and the output spot diameter is about 20 pm, and the focal depth satisfies the cleaning stability within ±0.5 mm range.

[0036] Third step: generate the cleaning path of the target pattern through the CAD drawing import method, and program the scanning strategy of contour priority + staggered filling in the system. The scanning speed is set to 100 mm / s, the scanning line overlap rate is 80%, and the cleaning process is completed by bidirectional scanning.

[0037] Fourth step: during the cleaning process, open the positive pressure nitrogen nozzle to cool the machining area and blow away the metal particles, and at the same time, start the air exhaust port to remove the molten debris, so as to prevent the re-deposition of the molten debris in the machining area or cause secondary pollution. Ultrasonic cleaning for 5-10 minutes.

[0038] Fifth step: clean the cleaning area by ultrasonic device for 5-10 minutes.

[0039] The sixth step: after cleaning, the processing area is evaluated by optical microscope and laser 3 confocal metal pattern topography, and the adjustment effect is confirmed combined with the electrical performance test result, and the effectiveness of the closed loop optimization is verified. The results show that the metal pattern is completely removed, the edge line is clear, there is no obvious burr or remelting phenomenon, and the substrate surface does not discolor or crack, which verifies the effectiveness and controllability of the process in high-precision and low-damage curved surface processing.

[0040] The present application is not limited to the above-mentioned optional embodiments, and anyone can derive other various forms of products under the inspiration of the present application, but regardless of any changes in shape or structure, any technical solutions falling within the scope defined by the claims of the present application fall within the protection scope of the present application.

Claims

1. A laser confined cleaning system for curved substrates, characterized in that: The system includes a control system (1) and a three-dimensional motion platform (7) electrically connected to the control system (1). A curved substrate (6) with a metal pattern to be cleaned is fixed on the three-dimensional motion platform (7). The control system (1) is electrically connected to a laser (2). A laser focusing unit is provided at the output end of the laser (2). The laser focusing unit is set on the curved substrate (6). The system also includes a visual auxiliary positioning system for recognizing the spatial posture of the metal pattern to be cleaned. The visual auxiliary positioning system is electrically connected to the control system (1). The control system (1) is also electrically connected to an intelligent reverse decision module. The intelligent reverse decision module is used to receive the deviation between the measured electromagnetic performance of the curved substrate (6) and the design target, automatically generate the corresponding material removal position, removal amount and laser cleaning parameters, and output them to the control system (1) for closed-loop adjustment.

2. The laser confined cleaning system for curved substrates according to claim 1, characterized in that: The laser focusing unit includes a mirror group (4) and a scanning galvanometer system (5). The laser (3) emitted from the laser (2) passes through the mirror group (4) and the scanning galvanometer system (5) in sequence before reaching the surface of the curved substrate (6).

3. The curved substrate laser confined cleaning system according to claim 1, characterized in that: The laser (2) is a femtosecond laser (2) or a picosecond laser (2), and the pulse width of the laser (2) is less than 10 ps.

4. The laser confined cleaning system for curved substrates according to claim 1, characterized in that: The laser (2) emits a laser (3) with a wavelength of 780nm or 1040nm, a laser (3) pulse energy of 10 to 30μJ, a laser (3) repetition frequency of 100kHz to 1MHz, and an average laser (3) power of 8 to 10W.

5. The laser confined cleaning system for curved substrates according to claim 1, characterized in that: The metal pattern to be cleaned on the curved substrate (6) is a gold plating layer with a thickness of 0.5 to 5 μm, or a copper layer, silver layer, or copper-silver alloy layer with a thickness of 5 to 20 μm.

6. A laser confined cleaning method for curved substrates, using the laser confined cleaning system for curved substrates according to any one of claims 1 to 5, characterized in that: Includes the following steps: S1: Fix the curved substrate (6) with the metal pattern to be cleaned onto the three-dimensional motion platform (7); S2: Identify the spatial pose of the target area through a vision-assisted positioning system, convert the spatial pose into a CAD model, and then generate a cleaning path through the CAD model; S3: The control system (1) controls the laser (2) to start. The control system (1) controls the posture of the three-dimensional motion platform (7) according to the cleaning path, so that the laser (3) cleans the metal pattern to be cleaned along the cleaning path. The incident angle of the laser (3) and the angle of the three-dimensional motion platform (7) are dynamically adjusted so that the incident direction of the laser (3) is controlled within ±5° of the normal direction of the target point of the metal pattern. S4: After completing the laser (3) cleaning, the cleaning area is cleaned by gas purging device and / or vacuum dust collection device to remove residue and perform surface treatment. S5: Perform electromagnetic performance testing on the cleaned curved substrate (6), input the results into the intelligent reverse decision module, automatically generate adjustment parameters based on performance deviation, and repeat steps S3 and S4 until the electrical performance meets the preset target.

7. The laser confined cleaning method for curved substrates according to claim 6, characterized in that: It also includes the following steps: S6: Clean the cleaning area for 5-10 minutes using an ultrasonic device.

8. The laser confined cleaning method for curved substrates according to claim 7, characterized in that: It also includes the following steps: S7: The processing area is evaluated by using an optical microscope and a laser (3) confocal curved substrate (6) morphology.

9. The laser confined cleaning method for curved substrates according to claim 6, characterized in that: In step S2, the cleaning path consists of contour-guided scanning and internal filling scanning, with an overlap rate of 70% to 90% between adjacent scan lines.

10. The laser confined cleaning method for curved substrates according to claim 6, characterized in that: In step S3, the laser (3) scanning speed is 50-200 mm / s, and the laser (3) spot diameter is 10-30 μm.

Images