Laser precision cleaning device based on two-dimensional galvanometer and intelligent adjustable light path and control method thereof

Abstract

The application relates to the technical field of micro electronic component surface precision cleaning, and particularly discloses a laser precision cleaning device based on a two-dimensional galvanometer and an intelligent adjustable light path and a control method thereof. The laser precision cleaning device comprises a gun head shell mounted on a moving mechanism, characterized in that: a collimating mirror moving plate is arranged at the front end of the gun head shell, a collimating mirror is mounted on the collimating mirror moving plate, an X-axis galvanometer, a field mirror and a Y-axis galvanometer are sequentially arranged in the gun head shell and located behind the collimating mirror; a Y-axis galvanometer moving plate is arranged on the rear end surface of the gun head shell, a galvanometer field mirror moving plate is arranged on the bottom surface of the Y-axis galvanometer moving plate, the Y-axis galvanometer is mounted on the Y-axis galvanometer moving plate, and the X-axis galvanometer is arranged on the galvanometer field mirror moving plate. The application effectively improves the surface contamination removal efficiency and precision of the micro electronic component, greatly reduces the thermal influence on the substrate and the damage risk in the cleaning process, and significantly improves the process stability and the yield rate in the micro electronic component production process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro electronic component surface precision cleaning, and particularly relates to a laser precision cleaning device based on a two-dimensional galvanometer and an intelligent adjustable light path and a control method thereof. BACKGROUND

[0002] With the rapid development of electronic technology, integrated circuits, micro sensors and micro electronic packaging and other small electronic components are widely used in the fields of aerospace, communication equipment, consumer electronics and the like. During the manufacturing, storage and transportation of these components, oxides, grease, dust and other pollutants are easily generated on the surface, which seriously affects the welding performance, electrical performance and use reliability of the components.

[0003] Traditional cleaning methods, such as chemical cleaning or mechanical brushing, have problems such as substrate damage, incomplete removal of pollutants or inability to accurately control the cleaning area. Existing laser cleaning equipment is generally designed for general use and commonly uses single-axis or fixed trajectory scanning methods, which have insufficient cleaning precision and poor spot trajectory adaptability, making it difficult to accurately avoid damage to sensitive areas during micro electronic component cleaning. At the same time, micro electronic components are usually small in size and complex in structure, requiring laser cleaning systems to have high positioning accuracy and flexibility. The light path structure of traditional equipment cannot meet the requirements of precise focusing and fine cleaning in such scenarios.

[0004] Therefore, there is an urgent need for a laser precision cleaning device that has intelligent, programmable two-dimensional scanning trajectories, high-precision fine-tuning light path positioning functions, and can realize real-time feedback of cleaning effect and precise parameter adjustment, to solve the deficiencies of existing technology in micro electronic component cleaning applications. SUMMARY

[0005] In order to overcome the deficiencies of the prior art and break through the technical bottleneck of the single light path trajectory and insufficient spatial adaptability of existing laser cleaning heads, the present application provides a laser precision cleaning device based on a two-dimensional galvanometer and an intelligent adjustable light path and a control method thereof.

[0006] The present application is realized by the following technical solutions:

[0007] A kind of laser precision cleaning device based on two-dimensional galvanometer and intelligent adjustable light path, including the gun head shell installed on moving mechanism, it is characterized in that: the front end of the gun head shell is provided with collimating mirror moving plate, collimating mirror is installed on collimating mirror moving plate and located in the inboard of laser incidence port, X-axis galvanometer, field lens and Y-axis galvanometer are sequentially arranged in the inside of gun head shell and located behind collimating mirror;Y-axis galvanometer moving plate is arranged on the rear end surface of gun head shell, and its bottom surface is provided with galvanometer field lens moving plate, Y-axis galvanometer is installed on Y-axis galvanometer moving plate, X-axis galvanometer is erected on galvanometer field lens moving plate, and field lens is installed on galvanometer field lens moving plate and located below X-axis galvanometer and Y-axis galvanometer;Moving mechanism is connected with gun head shell by X direction moving connecting rod, and is connected with galvanometer field lens moving plate by Y direction moving connecting rod.

[0008] The application includes a laser collimation system for collimating a divergent light beam output by a laser into parallel light, an X / Y-axis galvanometer scanning assembly for controlling the direction of the laser beam by swinging angle to realize two-dimensional scanning, a field lens focusing system for focusing and forming a programmable two-dimensional laser light panel, and a high-precision three-dimensional light path fine adjustment mechanism integrated in the gun head shell for driving the collimating mirror, the galvanometer and the field lens to perform fine adjustment displacement along the X and Y axes to adapt to the complex workpiece surface shape and narrow space. The device of the application generates programmable trajectories such as circle, line and polygon in a small area by two-dimensional galvanometer cooperative driving to efficiently remove oxides and micro-particle pollution on the surface of integrated circuits, electronic packaging and other devices. The moving mechanism can perform micron-level adjustment of the laser light path in the X / Y direction to adapt to the cleaning demand of complex microstructure.

[0009] The more optimal technical solution of the application is as follows.

[0010] The moving mechanism includes a base, step motor A and step motor B are installed on opposite sides of the base, two ball screw rods connected with the output shafts of the step motor A and the step motor B are erected in parallel on the base, two X-axis sliding rods parallel to the ball screw rods are installed on the base, a moving slider is sleeved on the X-axis sliding rod, two Y-axis sliding rods are arranged on the moving slider, one of the Y-axis sliding rods is provided with a rack, and two parallel moving sliding platforms are fixed at the ends of the two Y-axis sliding rods;Drive gear A is installed between the two ball screw rods in meshing manner, drive gear B is connected with drive gear A through a transmission shaft penetrating through the moving slider, drive gear B is in meshing with the rack, and the moving slider / moving sliding platform is driven to move by the same direction / opposite direction rotation of the ball screw rods, to realize high-precision linear motion along the X / Y direction, the displacement resolution is better than 10 μm, the maximum stroke is ± 50 mm, and the closed-loop feedback adjustment of the light path position is realized by an external controller.

[0011] Further preferably, the moving slider is connected with an X-direction moving connecting rod, the X-direction moving connecting rod is connected with the collimating mirror moving plate, the galvanometer field lens moving plate and the Y-axis galvanometer moving plate respectively; the moving sliding table is connected with a Y-direction moving connecting rod, the Y-direction moving connecting rod is connected with the galvanometer field lens moving plate.

[0012] Further preferably, the stepper motor A and the stepper motor B are installed with a subdivision drive controller, the drive gear A and the drive gear B are matched with an elastic pre-tightening mechanism and a linear encoder, so as to eliminate the backlash error and realize the micron-level positioning accuracy and the repeat positioning ability in cooperation with the linear encoder.

[0013] The inner side wall of the front end of the gun head shell is provided with an upper and lower symmetrical collimating mirror moving groove, and the collimating mirror moving plate is clamped in the collimating mirror moving groove; the bottom surface of the gun head shell is provided with a galvanometer field lens moving layer, and the galvanometer field lens moving plate is inserted in the galvanometer field lens moving layer; the rear end surface of the gun head shell is provided with a Y-axis galvanometer moving layer, and the Y-axis galvanometer moving plate is inserted in the Y-axis galvanometer moving layer, so as to realize the movement of each part in the gun head shell along the X direction. The inner wall of the gun head shell is provided with a graphene coating heat dissipation channel and an air cooling nozzle, and the two are combined to realize the temperature rise control within 5℃ during the high-efficiency work of the laser cleaning head.

[0014] Further preferably, the Y-axis galvanometer moving plate is provided with a nested structure, the rear end surface of the gun head shell is provided with a vertical long hole corresponding to the position of the nested structure, and the Y-axis galvanometer is clamped and fixed in the nested structure; the galvanometer field lens moving plate is provided with a Y-axis galvanometer fastener corresponding to the Y-axis galvanometer, a field lens fixing hole and a mounting sleeve corresponding to the X-axis galvanometer, the Y-direction moving connecting rod drives the galvanometer field lens moving plate to move along the Y direction, and then drives the X-axis galvanometer, the Y-axis galvanometer and the field lens to move along the Y direction.

[0015] The X-axis galvanometer and the Y-axis galvanometer are connected with a high-speed digital driver, the swing frequency range of the two is 100Hz to 5000Hz, the scanning accuracy is not less than 0.1mrad, and a plurality of control signal waveforms are supported, such as sine wave, square wave and self-defined arbitrary waveform; the field lens is an F-theta lens, the focal length range is 50mm-200mm, the spot diameter can be adjusted in the range of 20μm-100μm, and the focusing depth can be adjusted by ±5mm.

[0016] Based on the control method of the above laser precision cleaning device, the following steps are included:

[0017] (1) Selecting the laser spot shape (such as straight line, circle, square, etc.) and the corresponding scanning path according to the dirt type on the surface of different workpieces;

[0018] (2) The control signals of the X-axis galvanometer and the Y-axis galvanometer are generated, the laser spot shape is generated by the waveform of the galvanometer driving signal, the polygon and the complex curve track are supported, and the two-dimensional track scanning of the laser spot is realized;

[0019] (3) The overall position of the collimating mirror, the X-axis galvanometer, the Y-axis galvanometer and the field lens is adjusted through the moving mechanism, the light path is fine-tuned in the three-dimensional space, and the workpiece geometric structure is adapted;

[0020] (4) A preset cleaning parameter group is selected according to the target surface feature, the target area boundary is identified through real-time feedback, the laser track is dynamically planned and optimized, the laser power, the scanning speed and the galvanometer scanning parameter are adjusted through feedback, the cleaning path is ensured to avoid the sensitive area of the micro electronic component, and the cleaning quality is optimized.

[0021] Further preferably, in the step (4), the target surface feature extraction process integrates the image sensor and the cleaning effect analysis module, the target surface image is collected in real time through the real-time feedback system and the reflectivity, the texture feature and the boundary definition are analyzed, the laser power, the galvanometer frequency and the spot path density are automatically adjusted and the cleaning residue is judged; the laser cleaning parameter database is arranged in the cleaning system, and the matched spot shape, track form, power and frequency parameter combination are automatically selected from the database based on the identified pollution type and component arrangement, and the parameter adaptive matching is realized.

[0022] Further preferably, the real-time feedback system comprises a coaxial vision module, an image processing unit and a motion controller, wherein the coaxial vision module comprises a high-resolution CMOS camera and a narrow-band optical filter which are in the same light path as the cleaning laser, and is used for collecting the target area surface image; the image processing unit is used for performing the reflectivity difference analysis based on the regional gray homogeneity, the pollution classification based on the LBP texture spectrum and the GLCM matrix and the boundary definition detection based on the Canny edge gradient; and the motion controller dynamically adjusts the laser output power, the galvanometer scanning frequency and the moving platform offset according to the processing result, to form a closed-loop control.

[0023] The device is used for non-contact laser cleaning treatment of the surface of the micro electronic component including the oxide layer, the tin residue, the flux residue or the micro-particle pollution, and is particularly suitable for high-precision cleaning of the micro structure area such as the integrated circuit, the capacitor, the inductor and the pin connection area.

[0024] The beneficial technical effects of the present application are as follows:

[0025] (1) The high-speed and flexible two-dimensional spot track programming supports various complex graphic scanning, meets the customized cleaning needs of different workpiece surfaces and dirt, and especially meets the diversification and high-precision cleaning needs of the micro electronic component;

[0026] (2) Integrated high-precision three-dimensional fine adjustment moving mechanism, accurate adjustment of light path position, adaptation to complex geometric profile and narrow cleaning area of micro electronic components, avoidance of damage to sensitive areas, great expansion of application scenarios;

[0027] (3) Real-time visual feedback and intelligent parameter adaptive adjustment of cleaning parameters, dynamic optimization of laser power, scanning frequency and trajectory layout, ensuring cleaning effect while maximizing substrate protection, improving process safety and stability.

[0028] The present application effectively improves the efficiency and accuracy of removing surface contaminants of micro electronic components, greatly reduces the thermal influence and damage risk to the substrate during the cleaning process, and significantly improves the process stability and yield rate in the production process of micro electronic components. BRIEF DESCRIPTION OF DRAWINGS

[0029] The present application will be further described below in conjunction with the drawings.

[0030] Figure 1 is a schematic diagram of the overall structure of the present application;

[0031] Figure 2 is a schematic diagram of the back angle structure of the present application;

[0032] Figure 3 is a schematic diagram of the three-dimensional structure of the moving mechanism;

[0033] Figure 4 is a schematic diagram of the structure of the gun head shell;

[0034] Figure 5 is a schematic diagram of the structure of the galvanometer field mirror moving plate;

[0035] Figure 6 is a schematic diagram of the structure of the Y-axis galvanometer moving plate;

[0036] Figure 7 is a schematic diagram of the structure of the X-direction moving connecting rod;

[0037] Figure 8 is a schematic diagram of the structure of the Y-direction moving connecting rod.

[0038] In the figure, 1 collimating mirror, 2 gun head shell, 201 collimating mirror moving groove, 202 galvanometer field lens moving layer, 203 Y-axis galvanometer moving layer, 3 moving mechanism, 301 step motor A, 302 step motor B, 303 base, 304 ball screw, 305 drive gear A, 306 X-axis sliding rod, 307 moving slider, 308 moving sliding table, 309 drive gear B, 310 rack, 4 X-direction moving connecting rod, 5 Y-direction moving connecting rod, 6 galvanometer field lens moving plate, 601 Y-axis galvanometer fastener, 602 field lens fixing hole, 603 mounting sleeve, 7 X-axis galvanometer, 8 Y-axis galvanometer, 9 Y-axis galvanometer moving plate, 10 field lens, 11 collimating mirror moving plate. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objectives, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, a large number of specific details are set forth in order to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] The present application will be described in detail below with reference to the accompanying drawings.

[0042] Embodiment 1: A laser precision cleaning device based on two-dimensional galvanometer and intelligent adjustable light path

[0043] This embodiment includes a gun head shell 2 mounted on a moving mechanism 3, the front end of the gun head shell 2 is provided with a collimating mirror moving plate 11, the collimating mirror moving plate 11 is mounted with a collimating mirror 1 located inside the laser entrance port, and the inside of the gun head shell 2 is sequentially provided with an X-axis galvanometer 7, a field lens 10 and a Y-axis galvanometer 8 located behind the collimating mirror 1; the rear end surface of the gun head shell 2 is provided with a Y-axis galvanometer moving plate 9, and the bottom surface thereof is provided with a galvanometer field lens moving plate 6, the Y-axis galvanometer 8 is mounted on the Y-axis galvanometer moving plate 9, the X-axis galvanometer 7 is erected on the galvanometer field lens moving plate 6, and the galvanometer field lens moving plate 6 is mounted with the field lens 10 located below the X-axis galvanometer 7 and the Y-axis galvanometer 8; the moving mechanism 3 is connected with the gun head shell 2 through an X-direction moving connecting rod 4, and is connected with the galvanometer field lens moving plate 6 through a Y-direction moving connecting rod 5.

[0044] To ensure the efficient operation of the system, the structures of the components and the matching relationship are designed as follows:

[0045] (1) Collimating mirror 1: buckling installation + locking screw double fixation to ensure stability under the vibration environment of the laser.

[0046] (2) X-axis galvanometer 7 / Y-axis galvanometer 8: digital high-speed driver control with trajectory error compensation function to ensure trajectory accuracy; X-axis galvanometer 7 and Y-axis galvanometer 8 are controlled by high-speed digital drive, with swing frequency range of 100Hz to 5000Hz, scanning accuracy not less than 0.1mrad, supporting multiple control signal waveforms including sine wave, square wave and custom arbitrary waveform.

[0047] (3) Field lens 10: F-theta lens with focal length of 100mm is selected, supporting ±5mm focusing depth adjustment, suitable for micro-elevation difference area.

[0048] (4) Moving mechanism 3: driven by double-motor bidirectional ball screw system, high precision, fast response, supporting linear closed-loop control; attached to the gun head shell 2, and connected with the X-direction moving connecting rod 4 and the Y-direction moving connecting rod 5. Figure 3 It can be known that it comprises: collimating mirror 1 fixed inside the laser entrance aperture, used for collimating the divergent beam output by the laser into parallel light; gun head shell 2; moving mechanism 3; X-direction moving connecting rod 4; Y-direction moving connecting rod 5; galvanometer field lens moving plate 6; X-axis galvanometer 7 and Y-axis galvanometer 8, arranged in turn behind the collimating mirror 1, controlling the deflection direction of the laser beam by swing angle, realizing two-dimensional scanning; Y-axis galvanometer moving plate 9; field lens 10, located behind the X-axis galvanometer 7 / Y-axis galvanometer 8 group, used for focusing and forming programmable two-dimensional laser spot; collimating mirror moving plate 11, integrated in the gun head shell 2, driving the collimating mirror 1, galvanometer group and field lens 10 to move as a whole along the X and Y axes for fine adjustment displacement, to adapt to the complex workpiece surface shape and narrow space.

[0049] The moving mechanism 3 comprises: a stepper motor A 301 and a stepper motor B 302 for driving the ball screw 304 to rotate; a base 303; the ball screw 304 and the driving gear A 305 cooperate, the ball screw 304 is driven by the stepper motor A 301 and the stepper motor B 302 to rotate in the same direction, so as to realize driving the driving gear A 305 to complete forward and backward movement (at this time, the driving gear A 305 does not rotate, and is driven to move by the meshing with the ball screw 304), so as to drive the driving gear B 309 to move forward and backward, and then drive the moving slider 307 to complete forward and backward movement; the driving gear B 309 and the rack 310 cooperate with the moving slide 308, when the stepper motor A 301 and the stepper motor B 302 drive the ball screw 304 to rotate in the opposite direction, at this time, the ball screw 304 drives the driving gear A 305 to rotate, the driving gear B 309 drives the moving slide 308 to complete movement by meshing with the rack 310, realizes the X, Y high-precision linear motion, the displacement resolution is better than 10 μm, the maximum stroke is ± 50 mm; the closed-loop feedback adjustment of the optical path position is realized through the external controller.

[0050] As shown in the accompanying drawings Figure 4 The gun head shell 2 is provided with a collimating mirror moving groove 201, a galvanometer field mirror moving interlayer 202 and a Y-axis galvanometer moving interlayer 203, which are respectively used for installing the galvanometer field mirror moving plate 6, the collimating mirror moving plate 11 and the Y-axis galvanometer moving plate 9, and are used for realizing the movement of each part in the shell along the X direction. The Y-axis galvanometer moving plate 9 adopts a nested structure, which comprises an outer sleeve on the Y-axis galvanometer moving plate 9 and a Y-axis galvanometer fastener 601 on the galvanometer field mirror moving plate 6, which is fastened with the Y-axis galvanometer 8, and is used for realizing the Y-direction movement of the Y-axis galvanometer 8.

[0051] When the moving slider 307 in the moving mechanism 3 moves along the X direction, the moving mechanism 3 drives the X-direction moving connecting rod 4 to move, since the X-direction moving connecting rod 4 is connected with the collimating mirror moving plate 11, the galvanometer field mirror moving plate 6 and the Y-axis galvanometer moving plate 9, so as to drive each moving plate to move along the X direction, thereby driving the collimating mirror 1, the X-axis galvanometer 7, the Y-axis galvanometer 8 and the field mirror 10 to complete the X-direction movement. When the moving slide 308 in the moving mechanism 3 moves along the Y direction, the moving mechanism 3 drives the Y-direction moving connecting rod 5 to move, and the Y-direction moving connecting rod 5 is connected with the galvanometer field mirror moving plate 6, thereby driving the galvanometer field mirror moving plate 6 to move along the Y direction, so as to drive the X-axis galvanometer 7 on the mounting sleeve 603 and the field mirror 10 in the scene fixing hole 602 to move along the Y direction; the Y-axis galvanometer fastener 601 on the galvanometer field mirror moving plate 6 cooperates with the Y-axis galvanometer 8, so as to realize the Y-axis galvanometer 8 also moving along the Y direction.

[0052] (5) Heat dissipation system: the inner wall of the gun head shell 2 is coated with a graphene layer, combined with external air cooling nozzles, to realize temperature rise control ≤5℃ under power work.

[0053] Example 2: Control method for cleaning oxide layer of micro electronic components

[0054] The cleaning in this example uses the laser precision cleaning device described in Example 1, which uses a circular spot with a diameter of about 30 μm; laser power 200 W, galvanometer frequency 1 kHz; the moving mechanism is adjusted by ± 5 mm along the X / Y axis to avoid damaging the surrounding sensitive components; the galvanometer control signal is a sine wave, forming a circular scanning trajectory; the vision detection module collects images in real time and feeds back to adjust the cleaning parameters; after cleaning, there is no obvious damage to the substrate, and the oxide layer is effectively removed.

[0055] This example specifically describes the application of the laser precision cleaning device based on two-dimensional galvanometer and adjustable optical path described in Example 1 in the removal of oxide layer of micro electronic components. This cleaning task requires very high cleaning precision and protection of the surrounding sensitive structure, especially suitable for the removal of oxide layer on the surface of micro structure such as integrated circuit pin, capacitor, inductor and small size metal pad.

[0056] The optical path fine adjustment mechanism in this application uses high precision ball screw combined with gear and rack transmission structure, combined with digital stepper motor drive and multi-axis coupling connection, to realize micron level high precision positioning adjustment of the internal optical components of the laser cleaning head in X and Y directions.

[0057] The ball screw selects C5 grade high precision type, with lead control in the range of 1-2 mm, and is driven by a subdivided digital stepper driver, with the minimum step distance controllable below 0.01 mm. In the transmission chain, the gear and rack structure adopts helical tooth design and is equipped with elastic pre-tightening device, effectively eliminating the backlash error and reverse clearance problem, ensuring the positioning repeatability and response stability during forward and reverse movement.

[0058] In addition, the system further integrates a closed-loop position feedback device such as a linear encoder or a grating ruler, which is monitored in real time by the control system for the position of each moving shaft, and combined with error compensation algorithm, dynamically corrects the slight deviation caused by thermal expansion, mechanical clearance or load disturbance, ensuring the repeatability of the positioning accuracy better than 10 μm and the instantaneous displacement resolution better than 1 μm under long-term operation of the system.

[0059] This high precision fine adjustment structure ensures that the laser spot can be accurately focused on the target cleaning area, and is particularly suitable for non-contact cleaning operation on the local surface of complex pads, electrodes or micro structures in micro electronic components, providing a reliable hardware foundation for high precision cleaning control.

[0060] (1) Process preparation and cleaning target analysis

[0061] The target workpiece selected in this embodiment is a group of micro integrated circuit devices. The surface of the workpiece is covered with copper oxide layer due to long time exposure to humid air, which affects the welding and electrical performance. The device is small in size, and the minimum distance between components is 0.2 mm. It is required that the laser does not cause any ablation or thermal effect on the sensitive pads during the cleaning process.

[0062] According to the type of surface contamination (copper oxide, surface dust particles) and the cleaning area (about 2*2 mm per area), a pulsed light source with a wavelength of 1064 nm and a pulse width of 100 ns is selected, and the average power is set to 200 W.

[0063] (2) Laser parameter and spot trajectory setting

[0064] In order to achieve efficient and non-damaging cleaning effect, a circular laser spot with a diameter of about 30 μm is used. By controlling the X-axis and Y-axis galvanometer to generate phase-synchronized sinusoidal wave driving signals, the control frequency is 1 kHz, so as to form a regular circular scanning trajectory on the surface of the workpiece. This trajectory has the following advantages:

[0065] ①High uniform coverage of the trajectory: each circular trajectory continuously covers the surface of the workpiece area, avoiding omission or overexposure;

[0066] ②Uniform heat distribution: the scanning path is continuous and smooth, reducing heat concentration;

[0067] ③Adapt to the arrangement of microstructure: through the phase adjustment of the galvanometer waveform, the position and density of the scanning trajectory can be fine-tuned to adapt to different sizes of micro areas.

[0068] ④The spot path is generated by the trajectory template preset in the controller, and different path combinations can be loaded according to the component layout, which improves the versatility.

[0069] (3) Spatial positioning and fine-tuning mechanism

[0070] Due to the close arrangement of electronic components and the complex geometric profile, it is difficult to accurately focus on the required area with conventional fixed light path. This system introduces a high-precision three-axis moving mechanism, which drives the ball screw through the stepper motor, and realizes the fine positioning of the light path system in X and Y directions through the combination of X / Y axis moving connecting rod and moving slide. The accuracy is better than 10 μm, and the maximum stroke is ± 50 mm. In this cleaning process, the moving mechanism is dynamically fine-tuned by ± 5 mm along the X and Y axes, which realizes the following functions:

[0071] ①Position the laser focal point at the center of the area to be cleaned;

[0072] ②Accurately avoid the surrounding fragile components;

[0073] ③Realize quick alignment switching during batch cleaning of multiple areas.

[0074] The movement control is assisted by the host computer vision detection module, the image recognition system collects the workpiece surface image in real time, and through the identification of the to-be-cleaned area coordinates, boundaries and interference structures, the movement mechanism is instructed to realize the closed-loop precise alignment.

[0075] (4) Real-time feedback and parameter adaptive adjustment

[0076] In order to further ensure the stability and reliability of the cleaning quality, the device integrates visual detection and cleaning residue identification functions, and performs parameter adaptive adjustment through a real-time feedback system. During the cleaning process, the camera collects target area images at a frame rate of 30fps, and through algorithm identification of surface reflectivity change, texture information and edge contrast, judges the cleaning progress and residual situation.

[0077] The real-time feedback system includes a coaxial vision module, an image processing unit and a motion controller, wherein:

[0078] The coaxial vision module includes a high-resolution CMOS camera and a narrow-band optical filter in the same light path as the cleaning laser, which is used to collect target area surface images;

[0079] The image processing unit performs:

[0080] a) Reflectivity difference analysis based on regional gray mean value;

[0081] b) Contaminant classification based on LBP texture spectrum and GLCM matrix;

[0082] c) Boundary definition monitoring based on Canny edge gradient.

[0083] The motion controller dynamically adjusts the laser output power, galvanometer scanning frequency and mobile platform offset according to the processing result, forming a closed-loop control.

[0084] The specific detection principle and implementation steps are as follows:

[0085] A. Surface reflectivity detection

[0086] Principle basis: Laser reflectivity difference between contaminants and base material (oxide reflectivity ≈ 15%-30%, metal base material > 80%).

[0087] Algorithm flow:

[0088] ① Image segmentation:

[0089] Input: original image (1028*1024 pixels);

[0090] Output: to-be-cleaned area ROI;

[0091] Method: Otsu threshold segmentation + morphological opening operation.

[0092] ②Reflectance calculation:

[0093] Clean reference region mean gray value G_clean = 215 (8-bit gray scale);

[0094] Target region mean gray value G_target = np.mean(ROI);

[0095] Reflectance difference ratio R_diff = |G_target - G_clean| / G_clean.

[0096] ③Cleaning status determination:

[0097] If R_diff < 0.05 → "cleaned";

[0098] if 0.05 ≤ R_diff ≤ 0.3 → "cleaning";

[0099] if R_diff > 0.3 → "heavy pollution".

[0100] B. Texture feature recognition

[0101] Principle basis: Different pollutants have different texture differences in micro-morphology (oxide layer is granular, oil is film-shaped).

[0102] Algorithm flow:

[0103] ①Texture enhancement:

[0104] CLAHE contrast limited adaptive histogram equalization;

[0105] Gaussian difference filtering (σ1 = 1.0, σ2 = 3.0).

[0106] ②Feature extraction:

[0107] LBP (Local Binary Patterns) calculates local texture spectrum;

[0108] GLCM (Gray-Level Co-occurrence Matrix) extracts contrast / energy features.

[0109] ③Pollutant classification:

[0110] Table 1 Pollutant type

[0111] .

[0112] C. Edge contrast monitoring

[0113] Principle: The sensitivity area boundary sharpness change reflects the risk of laser offset.

[0114] Algorithm flow:

[0115] ① Edge extraction:

[0116] Canny operator detects the boundary (threshold 50-150);

[0117] Sub-pixel edge fitting (Zernike matrix algorithm).

[0118] ② Sharpness quantification:

[0119] Gradient amplitude calculation: G = √(Sobel_x² + Sobel_y²);

[0120] Boundary sharpness index: S = ∑G_edge / N_edge (N is the number of edge pixels).

[0121] ③ Safety distance control:

[0122] if S > S_threshold (preset safety value):

[0123] Generate offset command: ΔX = k * (S - S_threshold);

[0124] Actuator compensation: galvanometer angle adjustment or moving platform displacement.

[0125] This scheme has been verified in practice for 0402 package components (0.4 x 0.2 mm):

[0126] Contaminant identification accuracy: 98.7%;

[0127] Sensitivity area injury rate: <0.5%;

[0128] Single-point cleaning cycle: ≤50ms (including 30ms vision processing).

[0129] According to the image processing results, the system can adjust the following parameters in real time:

[0130] ① Laser power: if high-reflective impurities are still detected on the surface, the system automatically increases the laser energy by 5-10%;

[0131] ② Galvanometer scanning frequency and amplitude: if the scanning trajectory is uneven or the overlap is low, the system automatically adjusts the galvanometer sine wave frequency and phase difference;

[0132] ③ Scanning speed: when the cleaning surface response speed is slow, appropriately slow down the scanning speed to improve energy accumulation;

[0133] The above feedback mechanism ensures that the optimal balance between cleaning efficiency and substrate safety is maintained at different elements, different materials or different levels of surface contamination.

[0134] (5) Cleaning effect evaluation and comparison

[0135] After cleaning, the treated area is analyzed by microscope and energy dispersive spectrometer (EDS). The results show that:

[0136] Table 2 Comparison of effects of different cleaning methods

[0137]

[0138] As shown in the above table, after cleaning, the surface copper oxide is basically completely removed, with a residual rate of less than 0.5%; the substrate metal has no obvious discoloration, deformation or ablation marks; the boundary of the laser affected area is neat without overflow, and the width of the heat affected zone is less than 10 μm; the function of the nearby sensitive electronic components is not attenuated, and the electrical performance remains stable. Compared with traditional manual brushing or plasma cleaning process, the present scheme has the following advantages:

[0139] Compared with traditional manual brushing and plasma cleaning, the cleaning speed of the present embodiment (laser cleaning) is about 0.5 s / point ≥ 3 s / point, about 2 s / point, the substrate is protected without damage, programmable path customization is supported, and it is suitable for complex shapes with high automation.

[0140] The present application realizes diversified spot trajectories by two-dimensional programmable galvanometer scanning, breaks through the limitation of traditional single galvanometer or fixed trajectory, supports laser scanning of any complex two-dimensional trajectory, greatly improves the cleaning adaptability and efficiency; the three-dimensional fine adjustment optical path mechanism of the present application greatly improves the spatial adaptability, allows the optical path components to move with high precision in space, solves the problem of adapting to the narrow space and complex workpiece shape of precision cleaning of high-density microelectronic devices, and widens the application range; the intelligent closed-loop control of the present application guarantees the cleaning quality and substrate safety, realizes dynamic parameter optimization of the cleaning process, reduces the risk of substrate damage, and ensures stable and reliable cleaning effect; the structure is compact and has high-efficiency heat dissipation design, the inner wall of the gun head is coated with graphene and air-cooled nozzle for combined heat dissipation, which supports stable work of high-power laser, and ensures long-lasting durability of the equipment.

[0141] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and description of the present application.

Claims

1. A laser precision cleaning device based on two-dimensional galvanometer and intelligent adjustable light path, comprising a gun head shell (2) mounted on a moving mechanism (3), characterized in that: The front end of the gun head shell (2) is provided with a collimating mirror moving plate (11), the collimating mirror (1) is installed on the collimating mirror moving plate (11) and located inside the laser incident port, and the inside of the gun head shell (2) is sequentially provided with an X-axis galvanometer (7) located behind the collimating mirror (1), a field lens (10) and a Y-axis galvanometer (8); the rear end surface of the gun head shell (2) is provided with a Y-axis galvanometer moving plate (9), and the bottom surface thereof is provided with a galvanometer field lens moving plate (6), the Y-axis galvanometer (8) is installed on the Y-axis galvanometer moving plate (9), the X-axis galvanometer (7) is erected on the galvanometer field lens moving plate (6), and the galvanometer field lens moving plate (6) is installed with the field lens (10) located below the X-axis galvanometer (7) and the Y-axis galvanometer (8); the moving mechanism (3) is connected with the gun head shell (2) through an X-direction moving connecting rod (4) and connected with the galvanometer field lens moving plate (6) through a Y-direction moving connecting rod (5); The moving mechanism (3) comprises a base (303), step motors A (301) and step motors B (302) are installed on the opposite two sides of the base (303), two ball screws (304) connected with the output shafts of the step motors A (301) and the step motors B (302) are erected in parallel on the base (303), two X-axis sliding rods (306) parallel with the ball screws (304) are installed on the base (303), a moving slider (307) is sleeved on the X-axis moving rod (306), two Y-axis sliding rods are arranged on the moving slider (307), one of the Y-axis sliding rods is provided with a rack (310), and two parallel moving sliding platforms (308) are fixed at the two ends of the two Y-axis sliding rods; a driving gear A (305) is installed in meshing between the two ball screws (304), the driving gear A (305) is connected with a driving gear B (309) through a transmission shaft penetrating through the moving slider (307), and the driving gear B (309) is in meshing with the rack (310); The inside wall of the front end of the gun head shell (2) is provided with upper and lower symmetrical collimating mirror moving grooves (201), and the collimating mirror moving plate (11) is clamped in the collimating mirror moving grooves (201); the bottom surface of the gun head shell (2) is provided with a galvanometer field lens moving interlayer (202), and the galvanometer field lens moving plate (6) penetrates in the galvanometer field lens moving interlayer (202); the rear end surface of the gun head shell (2) is provided with a Y-axis galvanometer moving interlayer (203), and the Y-axis galvanometer moving plate (9) penetrates in the Y-axis galvanometer moving interlayer (203); the inner wall of the gun head shell (2) is provided with a graphene coating heat dissipation channel and an air cooling nozzle; The moving slider (307) is connected with an X-direction moving connecting rod (4), the X-direction moving connecting rod (4) is connected with the collimating mirror moving plate (11), the galvanometer field lens moving plate (6) and the Y-axis galvanometer moving plate (9) respectively, the moving sliding platform (308) is connected with a Y-direction moving connecting rod (5), and the Y-direction moving connecting rod (5) is connected with the galvanometer field lens moving plate (6); The Y-axis galvanometer moving plate (9) is provided with a nested structure, and the rear end surface of the gun head shell (2) is provided with a vertical long hole corresponding to the position of the nested structure, and the Y-axis galvanometer (8) is clamped and fixed in the nested structure; The field lens moving plate (6) is provided with a Y-axis galvanometer fastener (601) corresponding to the Y-axis galvanometer (8), a field lens fixing hole (602) and a mounting sleeve (603) corresponding to the X-axis galvanometer (7).

2. The laser precision cleaning apparatus of claim 1, wherein: The X-axis galvanometer (7) and the Y-axis galvanometer (8) are connected to a high-speed digital driver, and the swing frequency range of the two is 100Hz-5000Hz, and the scanning accuracy is not less than 0.1mrad; The field lens (10) is an F-theta lens, the focal length range is 50mm-200mm, the spot diameter can be adjusted in the range of 20μm-100μm, and the focusing depth can be adjusted by ±5mm.

3. The laser precision cleaning apparatus of claim 1, wherein: The stepping motor A and the stepping motor B are provided with a subdivision drive controller, and the drive gear A and the drive gear B are provided with an elastic pre-tightening mechanism and a linear encoder.

4. The control method of the laser precision cleaning apparatus according to claim 1, characterized in that, It comprises the following steps: (1) Selecting laser spot shape and corresponding scanning path according to different types of dirt on the surface of the workpiece; (2) Generating control signals of the X-axis galvanometer and the Y-axis galvanometer, the laser spot shape is generated by the waveform of the galvanometer drive signal, supporting polygon and complex curve trajectory, realizing two-dimensional trajectory scanning of the laser spot; (3) Adjusting the overall position of the collimating lens, the X-axis galvanometer, the Y-axis galvanometer and the field lens through the moving mechanism, realizing the fine adjustment of the optical path in three-dimensional space, adapting to the geometric structure of the workpiece; (4) Selecting a preset cleaning parameter group according to the target surface characteristics, and identifying the target area boundary through a real-time feedback system, dynamically planning and optimizing the laser trajectory, adjusting the laser power, scanning speed and galvanometer scanning parameters through feedback, ensuring that the cleaning path avoids the sensitive area of the micro electronic element, and optimizing the cleaning quality.

5. The control method according to claim 4, characterized by: In step (4), the target surface feature extraction process integrates an image sensor and a cleaning effect analysis module, which collects target surface images in real time and analyzes reflectivity, texture features and boundary definition through a real-time feedback system, realizes automatic adjustment of laser power, galvanometer frequency and spot path density, and judges cleaning residues; A laser cleaning parameter database is provided in the cleaning system, and based on the identified pollution type and element arrangement, a matching spot shape, trajectory form, power and frequency parameter combination is automatically selected from the database, realizing parameter adaptive matching.

6. The control method according to claim 4 or 5, characterized by: In step (4), the real-time feedback system includes a coaxial vision module, an image processing unit and a motion controller, wherein the coaxial vision module includes a high-resolution CMOS camera and a narrow-band optical filter in the same light path as the cleaning laser, which is used to collect the surface image of the target area; The image processing unit is used to perform reflectivity difference analysis based on regional gray homogeneity, pollution classification based on LBP texture spectrum and GLCM matrix, and boundary definition detection based on Canny edge gradient; The motion controller dynamically adjusts the laser output power, the galvanometer scanning frequency and the moving platform offset according to the processing result, forming a closed-loop control.

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