A laser cutting device and method for memory chip repair

Abstract

This application discloses a laser cutting apparatus and method for reworking memory chips. The apparatus includes: a fixture assembly for placing a circuit board and a memory chip to be cut on the circuit board; a laser mechanism disposed above the fixture assembly for non-contact laser cutting of the memory chip pins; the laser mechanism includes a 3D galvanometer for adjusting the laser focus position and controlling the laser cutting trajectory; and a visual positioning mechanism for acquiring images of the memory chip and performing positioning recognition to determine the laser cutting trajectory of the laser mechanism. This invention achieves high-precision, non-contact, automated cutting of chip pins through the efficient collaboration of visual positioning and the 3D galvanometer, effectively overcoming the defects of traditional rework methods that are prone to mechanical and thermal damage, and is beneficial to improving the yield and processing efficiency of memory chip rework.

Description

Technical Field

[0001] This application relates to the field of laser cutting technology, and in particular to a laser cutting apparatus and method for repairing memory chips. Background Technology

[0002] With the increasing integration of electronic products, memory chips are being used more and more widely on various circuit boards. Existing chip mounting methods mainly include surface mount and through-hole mounting, which are completed through traditional soldering methods such as reflow soldering or wave soldering, respectively.

[0003] However, in actual production and after-sales processes, memory chips often require rework due to issues such as poor soldering, solder bridging, damage, and upgrades. Existing rework methods typically rely on manual soldering and lead trimming, which are not only inefficient and have unstable yields, but also easily cause device damage, soldering defects, and contamination of the work surface, making it difficult to meet the batch rework needs of high-density, high-precision chips.

[0004] Therefore, there is an urgent need for a non-contact, high-precision processing method that can replace traditional rework methods to improve rework efficiency and finished product yield, and reduce labor costs and component scrap rate. Summary of the Invention

[0005] This application provides a laser cutting apparatus and method for reworking memory chips, aiming to solve the problem that existing memory chip rework operations cannot meet the rework requirements through manual soldering.

[0006] To achieve the above objectives, this application proposes a laser cutting apparatus for memory chip rework, comprising: A fixture assembly for placing a circuit board and the memory chips to be cut on the circuit board; A laser mechanism, disposed above the fixture assembly, is used for non-contact laser cutting of the pins of the memory chip; the laser mechanism includes a 3D galvanometer for adjusting the laser focus position and controlling the laser cutting trajectory; A visual positioning mechanism is used to acquire images of the memory chip and perform positioning recognition to determine the laser cutting trajectory of the laser mechanism.

[0007] In some embodiments, the fixture assembly includes a hollow fixture box and a vacuum extraction pipeline connected to the fixture box; the upper surface of the fixture box has a plurality of adsorption holes for vacuum adsorption positioning of the circuit board.

[0008] In some embodiments, at least two fixture boxes are provided, and the two fixture boxes are arranged side by side; each fixture box is provided with a Y-axis moving mechanism below it, and the fixture box is fixed to the movable end of the corresponding Y-axis moving mechanism.

[0009] In some embodiments, the laser mechanism includes a laser generator and an optical path guiding assembly for connecting the laser generator and the 3D galvanometer; the optical path guiding assembly is used to transmit the laser generated by the laser generator to the 3D galvanometer. The laser mechanism also includes a vertically arranged first mounting bracket, which is used to fix the 3D galvanometer and the optical path guiding assembly.

[0010] In some embodiments, the laser mechanism further includes a laser rangefinder for real-time detection of its height distance from the memory chip on the circuit board; the laser rangefinder is disposed on one side of the first mounting bracket, and the probe end of the laser rangefinder is positioned toward the fixture assembly.

[0011] In some embodiments, the visual positioning mechanism includes a vertically arranged second mounting bracket, an industrial camera fixed to the second mounting bracket, an optical lens connected to the bottom of the industrial camera, and a ring light source arranged around the bottom of the optical lens; The second mounting bracket is fixed to the first mounting bracket, and the second mounting bracket is disposed on the side of the laser mechanism opposite to the first mounting bracket.

[0012] In some embodiments, a dust removal assembly is further included, the dust removal assembly including a third mounting bracket and an annular suction pipe mounted on the lower end of the third mounting bracket; the third mounting bracket is connected to the first mounting bracket, the annular suction pipe is disposed directly below the 3D galvanometer, and the middle part of the annular suction pipe is hollowed out to avoid the laser cutting optical path.

[0013] In some embodiments, a nitrogen cooling assembly is further included for blowing nitrogen gas onto the memory chip during cutting; the nitrogen cooling assembly includes a bamboo-shaped conduit for delivering nitrogen gas, the bamboo-shaped conduit being disposed corresponding to the fixture assembly.

[0014] In some embodiments, the device further includes a worktable and a frame disposed on the worktable; the worktable is used to mount the Y-axis moving mechanism; the frame is provided with an X-axis moving mechanism, and the movable end of the X-axis moving mechanism is provided with a Z-axis moving mechanism, and the first mounting bracket is disposed at the movable end of the Z-axis moving mechanism.

[0015] Furthermore, this application also proposes a laser cutting method for memory chip rework, employing the laser cutting apparatus for memory chip rework as described above. The method includes the following steps: The circuit board containing the memory chip to be cut is placed on the jig box, and the jig box is used to vacuum adsorb and position it. Start the X-axis moving mechanism, Y-axis moving mechanism and Z-axis moving mechanism, and adjust the position of the fixture box and the laser mechanism so that the laser mechanism is aligned with the cutting position of the pin of the memory chip; The location information of the storage chip is captured by a visual positioning mechanism, the distance is measured by a laser rangefinder, and the data is fed back to the 3D galvanometer for dynamic focusing; the cutting trajectory is preset in the control system. The control system starts the X-axis moving mechanism, Y-axis moving mechanism, Z-axis moving mechanism and laser generator, and cuts the pins of the memory chip according to the preset cutting trajectory using a jump cutting method.

[0016] The beneficial effects of this application are as follows: This application uses a laser mechanism to perform non-contact cutting of the pins of memory chips, completely avoiding the mechanical stress tearing or thermal damage to the circuit board pads and surrounding precision components caused by traditional mechanical cutting methods, thus improving the yield rate of high-value memory chip rework. This application introduces a 3D galvanometer to control the laser focus position and cutting trajectory, which not only achieves high-speed, high-precision trajectory cutting, but also compensates for circuit board warping or chip height tolerances, ensuring consistent cutting. Combined with a vision positioning mechanism, this application can automatically acquire images and accurately identify the pin positions of the chip to be cut, providing precise processing coordinates for the laser mechanism. This eliminates errors from manual alignment, realizes automated closed-loop operation, and improves rework efficiency and batch production stability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the laser cutting apparatus for repairing memory chips according to this application; Figure 2 This is a schematic diagram of the laser mechanism structure of an embodiment of the laser cutting device for memory chip repair in this application; Figure 3 This is a schematic diagram of the visual positioning mechanism of an embodiment of the laser cutting apparatus for repairing memory chips according to this application; Figure 4 This is a schematic diagram of the cutting sequence of a jump-cutting method according to an embodiment of the laser cutting method for repairing memory chips in this application; In the diagram: 1. Fixture assembly; 11. Fixture box; 111. Adsorption hole; 12. Vacuum extraction pipeline; 2. Laser mechanism; 21. 3D galvanometer; 22. Laser generator; 23. Optical path guiding assembly; 24. First mounting bracket; 25. Laser rangefinder; 3. Visual positioning mechanism; 31. Second mounting bracket; 32. Industrial camera; 33. Optical lens; 34. Ring light source; 4. Y-axis moving mechanism; 41. Folding protective cover; 5. Dust removal components; 51. Third mounting bracket; 52. Annular suction duct; 6. Workbench; 7. Frame; 71. X-axis moving mechanism; 72. Z-axis moving mechanism; 8. Circuit board. Detailed Implementation

[0018] The solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments in this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0020] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0021] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0022] This application proposes a laser cutting device for memory chip repair, referring to... Figure 1 In one embodiment, the laser cutting apparatus for repairing the memory chip includes: Fixture assembly 1 is used to place circuit board 8 and the memory chip to be cut on circuit board 8; The laser mechanism 2 is disposed above the fixture assembly 1 and is used for non-contact laser cutting of the pins of the memory chip; the laser mechanism 2 includes a 3D galvanometer 21 for adjusting the laser focus position and controlling the laser cutting trajectory. The visual positioning mechanism 3 is used to acquire images of the storage chip and perform positioning recognition in order to determine the laser cutting trajectory of the laser mechanism 2.

[0023] In the rework or mass production of memory chips, the circuit board 8 may have slight warping, and it is difficult to ensure absolute flatness by manual placement. The fixture assembly 1 can achieve stable and accurate positioning of the circuit board 8 and the memory chip, ensuring that the workpiece to be processed is completely aligned with the laser cutting path, and providing a reliable physical benchmark for precise cutting.

[0024] Compared to the defects such as pin misalignment, thermal damage, electrostatic discharge, and residual metal debris that are easily caused by traditional manual lead trimming or soldering, this embodiment uses non-contact laser cutting, resulting in a minimal heat-affected zone that will not damage the memory chip or circuit board 8. The laser mechanism 2 includes a 3D galvanometer 21 for adjusting the laser focus position and controlling the laser cutting trajectory. The 3D galvanometer 21 can dynamically adjust the focusing lens angle and focal length to compensate for focal length changes in real time during processing, ensuring the laser spot remains in optimal focus. This allows the device to flexibly adapt to components of different heights and is particularly suitable for high-precision and high-consistency cutting of fine-pitch, micro-pins.

[0025] In actual operation, the visual positioning mechanism 3 automatically positions and corrects itself by capturing the edge contour on the circuit board 8 or the memory chip. It can guide the laser mechanism 2 to correct the cutting path in real time, eliminating errors such as cutting crookedly or incorrectly caused by manual positioning.

[0026] Reference Figure 1 In some embodiments, the jig assembly 1 includes a hollow jig box 11 and a vacuum extraction pipe 12 connected to the jig box 11; the upper surface of the jig box 11 is provided with a plurality of adsorption holes 111 for vacuum adsorption positioning of the circuit board 8.

[0027] Specifically, the fixture box 11 has a flat, rectangular hollow cavity structure, with its upper surface serving as the working surface for supporting the circuit board 8. Multiple adsorption holes 111 are evenly distributed in an array on the upper surface of the fixture box 11, and all adsorption holes 111 are connected to the hollow cavity inside the fixture box 11. One end of the vacuum extraction pipe 12 is connected to an external negative pressure generating device (not shown in the figure), and the other end is connected to the side of the fixture box 11, communicating with the internal cavity. When the vacuum extraction pipe 12 creates a vacuum, a negative pressure is formed inside the fixture box 11, which tightly adsorbs the circuit board 8 downwards through the adsorption holes 111, thereby eliminating the physical warpage that occurs during the mounting of the circuit board 8 and the chip.

[0028] Reference Figure 1 In some embodiments, at least two fixture boxes 11 are provided, and the two fixture boxes 11 are arranged side by side; a Y-axis moving mechanism 4 is provided below each fixture box 11, and the fixture box 11 is fixed to the movable end of the corresponding Y-axis moving mechanism 4.

[0029] Specifically, the Y-axis moving mechanism 4 includes a linear guide rail (not shown in the figure) and an accordion-style folding protective cover 41 covering the linear guide rail. Two jig boxes 11 arranged side-by-side are physically independent, with parallel linear guide rails laid on their bottoms, forming two independent movement channels. The bottom of each jig box 11 is fixed to the movable end of the corresponding linear guide rail by fasteners. Each jig box 11 can slide back and forth along its corresponding linear guide rail between the loading / unloading area and the cutting area under independent drive. This dual-station independent movement structure allows the device to simultaneously retract to the outside for manual unloading and reloading while laser cutting the product on one jig box 11, significantly improving efficiency.

[0030] Reference Figure 2 In some embodiments, the laser mechanism 2 includes a laser generator 22 and an optical path guiding component 23 for connecting the laser generator 22 and the 3D galvanometer 21; the optical path guiding component 23 is used to transmit the laser generated by the laser generator 22 to the 3D galvanometer 21. The laser mechanism 2 also includes a vertically arranged first mounting bracket 24, which is used to fix the 3D galvanometer 21 and the optical path guiding assembly 23.

[0031] Specifically, in this embodiment, the laser generator 22 is preferably a femtosecond fiber laser generator 22 that generates a wavelength of 1064nm. The laser generator 22 is hidden inside the device cabinet to ensure stable operation of the core light source and facilitate water cooling. The optical path guiding assembly 23 includes a flexible transmission optical fiber and an optical path adapter shell disposed outside the flexible transmission optical fiber. The optical path adapter shell has an L-shaped integrated structure, with a protective corrugated tube in the longitudinal part to protect the internal communication cables, and a rigid shell in the transverse part. One end of the flexible transmission optical fiber is connected to the laser generator 22, and the other end passes through the optical path adapter shell for dynamic bending protection, and finally connects laterally to the side input port of the 3D galvanometer 21.

[0032] In this embodiment, the first mounting bracket 24 is a high-rigidity metal backplate. The 3D galvanometer 21 is a box structure with a heat dissipation structure. The back of the 3D galvanometer 21 is directly fastened to one side of the first mounting bracket 24 by fasteners. The optical path adapter shell is also fixed to the same side of the first mounting bracket 24, adjacent to the 3D galvanometer 21. This suspended mounting structure allows the laser beam from the flexible transmission fiber to stably enter the galvanometer from the side and be focused downwards by the field lens at the bottom of the 3D galvanometer 21, without optical path jitter during vertical movement.

[0033] Reference Figure 2In some embodiments, the laser mechanism 2 further includes a laser rangefinder 25, which is used to detect the height distance between itself and the memory chip on the circuit board 8 in real time; the laser rangefinder 25 is disposed on one side of the first mounting bracket 24, and the detection end of the laser rangefinder 25 is disposed towards the fixture assembly 1.

[0034] Since the circuit board 8 to be processed often has slight warping, and the mounting height of memory chips from different batches may have tolerances, the laser rangefinder 25 is preferably a non-contact laser displacement sensor with micron-level precision. The laser rangefinder 25 is directly fixedly mounted on the lower end of the optical path adapter housing. This highly integrated structural design cleverly utilizes the optical path guiding component 23 as the mounting carrier for the laser rangefinder 25, ensuring that the laser rangefinder 25 and the 3D galvanometer 21 maintain a compact and parallel spatial linkage during the lifting and lowering process, greatly improving the physical accuracy of height-compensated detection.

[0035] Reference Figure 3 In some embodiments, the visual positioning mechanism 3 includes a vertically arranged second mounting bracket 31, an industrial camera 32 fixed on the second mounting bracket 31, an optical lens 33 connected to the bottom of the industrial camera 32, and an annular light source 34 arranged around the bottom of the optical lens 33. The second mounting bracket 31 is fixed to the first mounting bracket 24, and the second mounting bracket 31 is located on the side of the laser mechanism 2 away from the first mounting bracket 24.

[0036] Specifically, in terms of structural configuration and spatial arrangement, the optical lens 33 is preferably a high-magnification industrial lens to meet the high-definition imaging requirements of the micron-level pins of the memory chip. A ring light source 34 is coaxially mounted below the optical lens 33 to provide uniform, blind-spot-free vertical downward illumination, effectively eliminating image edge recognition errors caused by reflections or shadows. The second mounting bracket 31 is a longitudinally arranged elongated hanging plate. The industrial camera 32, optical lens 33, and ring light source 34 are sequentially mounted on the second mounting bracket 31 from top to bottom. The second mounting bracket 31 is fastened to the front side wall of the first mounting bracket 24 by bolts, i.e., the side of the laser mechanism 2 that protrudes outwards from the first mounting bracket 24. This staggered, side-by-side fixed structure ensures that the vision positioning mechanism 3 and the laser mechanism 2 maintain synchronous linkage in the X and Z axis directions. Furthermore, the industrial camera 32 is adjustablely mounted on the second mounting bracket 31 via a sliding groove, allowing it to slide up and down to fine-tune the physical focal length of the industrial camera 32 without altering the height of the laser mechanism 2.

[0037] Reference Figure 2In some embodiments, a dust removal component 5 is also included, which includes a third mounting bracket 51 and an annular suction pipe 52 mounted on the lower end of the third mounting bracket 51. The third mounting bracket 51 is connected to the first mounting bracket 24, and the annular suction pipe 52 is located directly below the 3D galvanometer 21. The middle part of the annular suction pipe 52 is hollowed out to avoid the laser cutting optical path.

[0038] Because femtosecond lasers generate a large amount of dense smoke and particulate dust instantaneously when vaporizing and cutting metal leads and burning surrounding substrates, failure to remove this dust promptly will severely affect the field mirror at the bottom of the 3D galvanometer 21. The annular dust extraction duct 52 has a U-shaped or closed rectangular hollow frame structure with a completely hollow center, suspended directly above the cutting area. This ensures that the laser beam focused from the 3D galvanometer 21 above can pass through the hollow center without obstruction and reach the chip leads below. The rear side of the annular dust extraction duct 52, facing away from the cutting area, is connected to a smoke exhaust port for connecting an external negative pressure ventilation system.

[0039] In addition, the third mounting bracket 51 is connected to the first mounting bracket 24 via a suspension arm that passes over the 3D galvanometer 21. The length of the suspension arm is adjustable, thereby changing the hanging height of the annular suction pipe 52 to accommodate circuit boards 8 of different specifications. During cutting, the annular suction pipe 52 forms a micro negative pressure suction field around the cutting point, which removes the generated smoke and dust, ensuring that the laser is not scattered by the smoke and maintaining the cleanliness of the equipment.

[0040] Reference Figure 1 In some embodiments, the system further includes a worktable 6 and a frame 7 disposed on the worktable 6; the worktable 6 is used to install the Y-axis moving mechanism 4; the frame 7 is provided with an X-axis moving mechanism 71, and the movable end of the X-axis moving mechanism 71 is provided with a Z-axis moving mechanism 72, and the first mounting bracket 24 is disposed at the movable end of the Z-axis moving mechanism 72.

[0041] In terms of overall structure, the worktable 6 provides a stable base for high-precision machining, and the frame 7 is preferably a gantry structure straddling the worktable 6. Specifically, the laser generator 22 of the laser mechanism 2 is stably mounted on the top beam of the gantry; at the same time, the X-axis moving mechanism 71 is horizontally mounted on the top beam of the gantry, and the Z-axis moving mechanism 72 is vertically mounted on the movable end of the X-axis moving mechanism 71. The first mounting bracket 24, which carries the laser mechanism 2 and the vision positioning mechanism 3, is mounted on the movable end of the Z-axis moving mechanism 72. The design of placing the laser generator 22 directly on the top beam of the gantry not only effectively utilizes the space above the frame 7, but also significantly shortens the routing length of the flexible optical fiber connected to the 3D galvanometer 21, effectively reducing energy loss in optical path transmission and the mechanical risk of optical fiber bending.

[0042] In terms of three-axis coordination and machining linkage, the Y-axis moving mechanism 4, fixed on the worktable 6, is responsible for carrying the fixture assembly 1 and the memory chip to be processed for precise feeding in the front-to-back direction; the X-axis moving mechanism 71, carried by the upper frame 7, is responsible for driving the laser mechanism 2 to move across the left and right directions; and the Z-axis moving mechanism 72 is responsible for the vertical feeding of the laser mechanism 2. Through the upper and lower separation design of the bottom Y-axis and the top X and Z axes, three-axis spatial all-round linkage positioning can be achieved. This structure not only effectively distributes the moving load and reduces mechanical vibration, but also ensures that the 3D galvanometer 21 and the vision positioning mechanism 3 suspended above can quickly and accurately align with the memory chip pins at any position on the fixture box 11, thereby completing fully automated and efficient continuous processing.

[0043] In some embodiments, a nitrogen cooling assembly (not shown) is also included, which is used to blow nitrogen gas to the memory chip during cutting; the nitrogen cooling assembly includes a bamboo-shaped tube for conveying nitrogen gas, which is disposed corresponding to the fixture assembly 1.

[0044] Laser high-temperature cutting requires nitrogen blowing to reduce the thermal effects on materials, such as melting edges and scorching. The core gas guiding component of the nitrogen cooling assembly is a flexible, shape-maintaining plastic or metal tube. To accommodate different component interference situations and space requirements, the nitrogen cooling assembly has different structural installation methods: One is a platform-fixed installation: the fixed air inlet end of the tube is directly fixed to the worktable 6 via a bracket, with the tube extending close to the fixture assembly 1, and the air outlet on the tube precisely aimed laterally at the cutting area above the fixture assembly 1. The second is a suspended, follow-up installation: the tube is suspended on the first mounting bracket 24, or integrated using a suspension component similar to the third mounting bracket 51 in the aforementioned dust removal assembly 5. In this method, the air outlet on the tube is tilted at a certain angle from top to bottom, aimed at the cutting area above the fixture assembly 1. The advantage of the suspended design is that the nitrogen blowing port can always move synchronously with the X / Z axis of the laser mechanism 2, achieving real-time dynamic local gas protection. Regardless of the installation method, the bamboo-joint tube can be easily bent to change the air blowing angle and distance. The inert nitrogen gas sprayed through the bamboo-joint tube can displace the oxygen around the processing point to prevent the lead cross-section from oxidizing and turning black. At the same time, the airflow quickly removes the high temperature and tiny slag generated during cutting, thereby obtaining a smooth and flat cut surface.

[0045] Furthermore, this application also proposes a laser cutting method for memory chip rework, employing the laser cutting apparatus for memory chip rework as described above. In one embodiment, the laser cutting method for memory chip rework includes the following steps: First, the circuit board 8 containing the memory chip to be cut is placed on the jig box 11, and the jig box 11 is used to vacuum adsorb and position it. Next, the X-axis moving mechanism 71, Y-axis moving mechanism 4, and Z-axis moving mechanism 72 are activated to adjust the position of the fixture box 11 and the laser mechanism 2 so that the laser mechanism 2 is aligned with the cutting position of the memory chip pins. The Y-axis moving mechanism 4 can smoothly feed the circuit board 8 on the fixture box 11 from the external loading and unloading area into the internal laser cutting area. The X-axis moving mechanism 71 and Z-axis moving mechanism 72 make the laser mechanism 2 move quickly and initially align with the cutting position of the memory chip pins.

[0046] Then, the position information of the storage chip is captured by the visual positioning mechanism 3, the distance is measured by the laser rangefinder 25 and fed back to the 3D galvanometer 21 for dynamic focusing; the cutting trajectory is preset in the control system. Specifically, the visual positioning mechanism 3 can capture the position information of the MARK point or edge contour of the memory chip and generate positioning correction information to completely eliminate the slight positional error of manual material placement; at the same time, the laser rangefinder 25 detects the actual height distance between the laser lens and the current pin in real time and feeds the height data back to the 3D galvanometer 21 for dynamic focusing and height compensation to ensure that the laser focal plane perfectly fits the pin surface; subsequently, the 3D cutting software of the control system generates and presets a high-precision three-dimensional cutting trajectory based on the positioning correction information and height data.

[0047] Finally, the control system starts the X-axis moving mechanism 71, Y-axis moving mechanism 4, Z-axis moving mechanism 72 and laser generator 22, and cuts the pins of the memory chip according to the preset cutting trajectory using the jump cutting method.

[0048] Specifically, refer to Figure 4 The jump-cutting method breaks away from the traditional method of cutting sequentially along the physical arrangement of pins, such as from top to bottom or from left to right. Instead, it adopts a skip-and-scramble sequence for large-span alternating cuts. For example, the 3D galvanometer 21 first focuses on cutting the pin on the upper left side of the chip (position S1), and after an instant cut, the laser beam immediately jumps to the lower right pin (position S2) which is diagonally opposite or further away, and then jumps to the middle left side (position S3), the middle right side (position S4), and so on, performing a skip-cutting process in a cyclical manner. By adopting this jump-cutting method, concentrated and continuous heat energy accumulation can be effectively avoided, significantly reducing the continuous heat input to local materials and preventing thermal damage such as melting and scorching of surrounding substrates and pins due to heat accumulation. Ultimately, a cut section with consistent dimensions and a smooth surface is obtained.

[0049] In summary, the laser cutting device and method for reworking memory chips provided by this invention have the following significant technical advantages compared to traditional soldering or manual lead trimming rework methods that heavily rely on manual experience: This invention uses a femtosecond fiber laser with a wavelength of 1064nm in conjunction with a 3D galvanometer 21 to achieve non-contact cutting. Combined with the automatic correction of the vision positioning mechanism 3 and the dynamic height compensation of the laser rangefinder 25, it eliminates height fluctuations caused by manual material feeding errors and micro-warping of the board surface, avoiding lead misalignment and physical stress damage, and is suitable for the high-precision processing requirements of fine-pitch, micro-packaged chips such as QFP and BGA. The dual-station Y-axis moving mechanism 4, in conjunction with the vacuum-adsorption fixture box 11, achieves efficient and stable alternating material feeding; simultaneously, the nitrogen cooling component and the fume extraction component 5 provide airflow control, effectively cooling the processing surface and removing processing dust, preventing high-temperature oxidation and blackening of the leads, and protecting the device lens. This invention breaks away from the traditional sequential cutting logic. Under the control of the software system, it adopts a scrambled alternating cutting method to process the pins, which effectively disperses the concentrated heat energy generated by laser cutting and greatly reduces the continuous heat input to local materials. This results in minimal surface spatter during the cutting process and completely eliminates defects such as melting edges and scorching caused by heat accumulation on the surrounding PCB substrate and chip body, ultimately obtaining a highly consistent flat cutting section.

[0050] This invention automates and standardizes the tedious and high-risk traditional rework process, significantly reducing reliance on skilled workers and labor costs, eliminating human error, and providing a highly stable, efficient, and yield-high-quality solution for the rework and mass production of high-density electronic products.

[0051] The above description is only a part or preferred embodiment of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. A laser cutting device for repairing memory chips, characterized in that, include: A fixture assembly for placing a circuit board and the memory chips to be cut on the circuit board; A laser mechanism, disposed above the fixture assembly, is used for non-contact laser cutting of the pins of the memory chip; the laser mechanism includes a 3D galvanometer for adjusting the laser focus position and controlling the laser cutting trajectory; A visual positioning mechanism is used to acquire images of the memory chip and perform positioning recognition to determine the laser cutting trajectory of the laser mechanism.

2. The laser cutting apparatus for reworking memory chips according to claim 1, characterized in that, The fixture assembly includes a hollow fixture box and a vacuum extraction pipeline connected to the fixture box; the upper surface of the fixture box has multiple adsorption holes for vacuum adsorption positioning of the circuit board.

3. The laser cutting apparatus for reworking memory chips according to claim 2, characterized in that, At least two fixture boxes are provided, and the two fixture boxes are arranged side by side; each fixture box is provided with a Y-axis moving mechanism below it, and the fixture box is fixed to the movable end of the corresponding Y-axis moving mechanism.

4. The laser cutting apparatus for reworking memory chips according to claim 3, characterized in that, The laser mechanism includes a laser generator and an optical path guiding assembly for connecting the laser generator and the 3D galvanometer; the optical path guiding assembly is used to transmit the laser generated by the laser generator to the 3D galvanometer. The laser mechanism also includes a vertically arranged first mounting bracket, which is used to fix the 3D galvanometer and the optical path guiding assembly.

5. The laser cutting apparatus for reworking memory chips according to claim 4, characterized in that, The laser mechanism also includes a laser rangefinder, which is used to detect the height distance between itself and the memory chip on the circuit board in real time; the laser rangefinder is disposed on one side of the first mounting bracket, and the detection end of the laser rangefinder is positioned towards the fixture assembly.

6. The laser cutting apparatus for reworking memory chips according to claim 4, characterized in that, The visual positioning mechanism includes a vertically arranged second mounting frame, an industrial camera fixed on the second mounting frame, an optical lens connected to the bottom of the industrial camera, and a ring light source arranged around the bottom of the optical lens; The second mounting bracket is fixed to the first mounting bracket, and the second mounting bracket is disposed on the side of the laser mechanism opposite to the first mounting bracket.

7. The laser cutting apparatus for reworking memory chips according to claim 4, characterized in that, It also includes a dust removal component, which includes a third mounting bracket and an annular suction pipe installed at the lower end of the third mounting bracket; the third mounting bracket is connected to the first mounting bracket, and the annular suction pipe is located directly below the 3D galvanometer, with a hollowed-out middle section to avoid the laser cutting optical path.

8. The laser cutting apparatus for repairing memory chips according to claim 1, characterized in that, It also includes a nitrogen cooling assembly for blowing nitrogen gas onto the memory chip during cutting; the nitrogen cooling assembly includes a bamboo-shaped tube for conveying nitrogen gas, the bamboo-shaped tube being configured corresponding to the fixture assembly.

9. The laser cutting apparatus for reworking memory chips according to claim 4, characterized in that, It also includes a worktable and a frame mounted on the worktable; the worktable is used to mount the Y-axis moving mechanism; the frame is provided with an X-axis moving mechanism, and the movable end of the X-axis moving mechanism is provided with a Z-axis moving mechanism, and the first mounting bracket is provided at the movable end of the Z-axis moving mechanism.

10. A laser cutting method for reworking memory chips, characterized in that, The method using the laser cutting apparatus for memory chip rework as described in any one of claims 1-9 includes the following steps: The circuit board containing the memory chip to be cut is placed on the jig box, and the jig box is used to vacuum adsorb and position it. Start the X-axis moving mechanism, Y-axis moving mechanism and Z-axis moving mechanism, and adjust the position of the fixture box and the laser mechanism so that the laser mechanism is aligned with the cutting position of the pin of the memory chip; The location information of the storage chip is captured by a visual positioning mechanism, the distance is measured by a laser rangefinder, and the data is fed back to the 3D galvanometer for dynamic focusing; the cutting trajectory is preset in the control system. The control system starts the X-axis moving mechanism, Y-axis moving mechanism, Z-axis moving mechanism and laser generator, and cuts the pins of the memory chip according to the preset cutting trajectory using a jump cutting method.

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