Ultra-short pulse laser processing method and equipment for fitting path along Bezier curve
Through the ultra-short pulse laser processing method along the Bezier curve fitting path, high-precision curve etching is achieved using dynamic focus galvanometer and multi-axis assisted motion, the problem of low accuracy of curve laser etching and thermal damage is solved, and the problem of low curve laser etching is realized. High-efficiency micromachining without thermal effects is achieved, and the processing accuracy and efficiency of microelectronic devices are improved.
Patent Information
- Application Number
- CN202411405248.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-10
- Publication Date
- 2024-12-27
AI Technical Summary
In the prior art, curve laser scribe processing has problems such as low accuracy, edge collapse and thermal damage, especially when dealing with microelectronic devices, it is difficult to avoid material damage.
Using ultra-short pulse laser processing method along the Bezier curve fitting path, the ultra-short pulse laser is projected to the curve surface of the workpiece to be processed through a dynamic focus galvanometer, and high-precision curve fit is achieved using a multi-axis assisted motion and visual positioning system. , avoid the occurrence of thermal effects. The method includes a bearing platform, visual positioning system, control system, dynamic focus galvanometer, atmosphere guarantee system and laser generation system. The real-time vector of path points is generated through Bezier curve fitting to achieve high-precision marking of various morphological curves .
It realizes efficient and high-quality linear etching micromachining without thermal effects, avoids ablation damage caused by continuous wave laser or long pulse laser, and improves the processing accuracy and output efficiency of microelectronic devices.
Smart Images
Figure CN119187847A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of laser processing equipment, and in particular relates to an ultra-short pulse laser processing method and equipment along a Bezier curve fitting path. Background Art
[0002] In recent years, with the continuous growth of the market, the requirements for production capacity and yield of microelectronic device manufacturing industries such as LED wafers, IC chips and graphene devices have become increasingly higher. Laser processing technology has quickly become a common tool in the microelectronics manufacturing industry. At present, laser scribing has become the industrial standard for high-brightness LED wafer processing. Common materials for microelectronic devices such as wafers and chips are gallium nitride, gallium arsenide and single crystal sapphire, which are hard and brittle materials, so it is difficult to cut them into monomer devices. When cutting these materials with traditional mechanical saw blades, it is easy to cause damage such as edge collapse, microcracks, and delamination. Therefore, when using the saw blade cutting method, a wide width must be retained between monomers to avoid cutting and cracking to damage the device, which greatly reduces the output efficiency of microelectronic devices. The laser scribing lines are much narrower than traditional mechanical scribing, so the material utilization rate is significantly improved. In addition, laser processing is a non-contact process. As an alternative to traditional mechanical saw blade cutting, the laser scribing cut size is small, and the wafer surface acted on by the focused laser fine spot quickly removes materials, so that more monomers can be cut on a limited area of the wafer, improving the output efficiency.
[0003] With the development of laser processing technology, laser scribing using ultrashort laser pulses such as picoseconds and femtoseconds has become a new development trend in the field of microelectronic chips. Since the pulse width (i.e., single pulse action time) of ultrashort laser pulses such as picoseconds and femtoseconds is at the same order of magnitude as the heat transfer time between lattices, the thermal effect can be fully avoided during the processing process. The microcracks and thermal damage caused by ultrashort pulse laser scribing are smaller, the output efficiency is high, and the reliability of the finished device is greatly improved. Therefore, ultrashort pulse laser scribing is particularly suitable for the processing of hard and brittle semiconductor wafer materials such as gallium nitride and gallium arsenide, and has the advantages of high efficiency, high precision, low cost, and high reliability.
[0004] Due to the complexity of the microelectronic chip structure, in addition to straight line engraving, there is now a corresponding demand for high-precision curve laser engraving. There are currently two different vector fitting methods for the actual digital control of the curve laser engraving process: (1) discretizing the curve into multiple line segments for fitting; (2) discretizing the curve into multiple line segments and arcs for fitting. Both of these vector fitting methods will produce large fitting errors in high-precision curve engraving. Summary of the invention
[0005] The main purpose of the present invention is to provide an ultrashort pulse laser processing method and equipment along a Bezier curve fitting path to solve the problems of low curve fitting accuracy, edge collapse, thermal damage, etc. in the laser scribing method used in the prior art.
[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided an ultrashort pulse laser processing method along a Bezier curve fitting path, wherein an ultrashort pulse laser is projected onto the surface of a workpiece to be processed by a dynamic focusing galvanometer, the workpiece to be processed is supported by a supporting platform below and subjected to multi-axis auxiliary motion, and the scanning trajectory of the laser spot on the surface of the workpiece to be processed is made to coincide with a predetermined processing path through the dual coordinate system linkage of the focusing galvanometer and the supporting platform, and the predetermined processing path is determined by a starting point, an anchor point and two intermediate control points, and the predetermined processing path is fitted with a Bezier curve to determine the real-time vector of the path point, thereby realizing ultrashort pulse laser engraving of various morphological curves on the surface of the workpiece to be processed.
[0007] Furthermore, the Bezier curve is generated by substituting the selected N-1 control points into the N-order Bezier curve formula and then performing recursive calculation.
[0008] According to another aspect of the present invention, there is provided an ultrashort pulse laser processing equipment along a Bezier curve fitting path, the equipment adopts an ultrashort pulse laser processing method along a Bezier curve fitting path according to any one of the aforementioned first aspects, and the equipment mainly includes a carrying platform, a visual positioning system, a control system, a dynamic focusing galvanometer, a line engraving processing area, an atmosphere guarantee system, an online monitoring system, and a laser generation system.
[0009] Loading platform: mainly composed of servo motor, coupling, guide rail, hinge, axis X1, axis Y1, axis Z1, protective device, power supply A, sensor, work table and tooling. The servo motor moves axis X1, axis Y1 and axis Z1 through the coupling, the hinge moves synchronously, the workpiece is fixed on the work table through the tooling, and the workpiece and tooling move with the work table. The load-bearing platform is equipped with a pressure sensor to monitor the load status of the load-bearing platform, and can automatically adjust the opening time and safety lock of the laser pulse according to the load status.
[0010] Visual positioning system: mainly includes high-speed high-definition camera, image processing system, and servo drive. The camera samples the workpiece on the stage, cooperates with the image processing system and servo drive to establish the processing coordinate system and path control points for processing the workpiece surface, and transmits them to the control system through communication.
[0011] Control system: including human-machine interface and control card, which can display parameters such as drive axis, laser output power, temperature and humidity, and processing spot diameter on the human-machine interface; the control card mainly communicates, processes, and transforms information of servo motor, drive, dynamic focusing galvanometer, laser, power supply, atmosphere purification system, and online monitoring system. According to the geometric features of the digital model of the space surface to be processed, the curve path point vector fitting is automatically performed on the predetermined line engraving path to achieve continuous line engraving micro-machining of curves of different shapes and the automatic call and operation of laser line engraving process parameters.
[0012] Dynamic focusing galvanometer: The dynamic focusing galvanometer consists of an X2-axis swing mirror, a Y2-axis swing mirror, a Z2-axis drive, a sensor, a data transmission system, and a power supply. The X2-axis swing mirror, the Y2-axis swing mirror, the Z2-axis drive, and the sensor work together to achieve the spatial change of the laser focus, and the control system provides a processing coordinate system converted by the visual positioning system for data simulation processing.
[0013] Line engraving processing area: The line engraving processing area is equipped with special tooling to achieve fast replacement of workpieces of different shapes, consistent interfaces, and convenient calculation of coordinate points, ensuring fast conversion of processing programs.
[0014] Atmosphere support system: The atmosphere support system is mainly composed of dust removal system, etc.; the dust removal system collects and filters the vaporized substances and dust particles generated by the laser during the processing.
[0015] Online monitoring system: Install pressure sensors on the load-bearing platform, motion sensors on each axis of the galvanometer, and smoke sensors on the atmosphere purification system to achieve real-time monitoring of the status of subsystems such as the load on the load-bearing platform, the light output of the galvanometer, and the atmosphere purification system, and display the working status parameters on the human-machine interface and issue early warnings.
[0016] Laser generation system: The laser generation system is mainly composed of laser, laser power supply, cooling device, dehumidification device, etc. The laser provides a reliable ultra-short pulse laser light source, which can directly or indirectly (beam expander) provide a light spot that meets the controllable range of the dynamic focusing galvanometer; the laser power supply provides energy, data and other information for the laser, establishes communication with the control card, and meets the surface parameter requirements of the processed workpiece; the cooling device mainly guarantees the working temperature of the high-precision optical components inside the laser generator, so that it can perform tasks within the allowable parameter range; the dehumidification device mainly provides a strong working environment guarantee for the laser generation system, so that the dew point temperature can be controlled and meet the requirements of ultrafast laser pulse line micromachining workpieces.
[0017] Furthermore, the control system can automatically perform curve path point vector fitting on a predetermined line engraving path according to the geometric features of the digital model of the spatial surface to be processed, thereby realizing continuous line engraving micromachining of curves of different shapes.
[0018] Furthermore, the control system can realize the automatic calling and operation of laser engraving process parameters.
[0019] Furthermore, during the wire-etching micromachining process, the atmosphere guarantee system can timely remove the vaporized residues and dust particles generated when the laser removes the material, thereby improving the quality of the wire-etching micromachining.
[0020] Furthermore, the carrying platform is equipped with a pressure sensor, which can monitor the load status of the carrying platform and automatically adjust the opening time and safety lock of the laser pulse according to the load status.
[0021] In summary, the ultrashort pulse laser processing method and equipment along the Bezier curve fitting path provided by the present invention can realize efficient and high-quality line micromachining without thermal effects, and eliminate the ablation damage caused by the thermal effects of continuous wave lasers or long pulse lasers. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a structural diagram of the ultrashort pulse laser processing equipment along the Bezier curve fitting path of the present invention;
[0023] Figure 2 It is a schematic diagram of the carrying platform of the ultrashort pulse laser processing equipment along the Bezier curve fitting path of the present invention;
[0024] Figure 3 It is a schematic diagram of the tooling assembly of the ultrashort pulse laser processing equipment along the Bezier curve fitting path of the present invention;
[0025] Figure 4 It is a schematic diagram of a dynamic focusing galvanometer of an ultrashort pulse laser processing equipment along a Bezier curve fitting path of the present invention;
[0026] Figure 5 It is a schematic diagram of the laser generating system of the ultrashort pulse laser processing equipment along the Bezier curve fitting path of the present invention.
[0027] Reference numerals:
[0028] 100: Carrying platform; 200: Tooling components; 300: Visual positioning system; 400: Dynamic focusing galvanometer
[0029] 500: Laser generation system; 600: Control system; 700: Online monitoring system; 800: Body components
[0030] 1: servo motor 1; 2: coupling 1; 3: X1 axis; 4: guide rail 1; 5: Y1 axis; 6: coupling 2
[0031] 7: servo motor 2; 8: guide rail 2; 9: hinge; 10: table; 10A: pressure sensor; 11: guide rail 3;
[0032] 12: Z1 axis; 13: Coupling 3; 14: Servo motor 3; 15: Workpiece; 16: Tooling; 17: X2 axis swing mirror
[0033] 18: Y2 axis swing mirror; 19: Z2 axis; 20: sensor; 21: galvanometer power supply; 22: transmission system
[0034] 23: beam expansion device; 24: induction device; 25: laser generator; 26: laser power supply; 27: cooling system
[0035] 28: Dehumidification system. DETAILED DESCRIPTION
[0036] The following is a further detailed description of the ultrashort pulse laser processing method and equipment along the Bezier curve fitting path of the present invention in conjunction with the accompanying drawings and specific examples:
[0037] 1. The carrying platform 100, the tooling assembly 200, the visual positioning system 300, the dynamic focusing galvanometer 400, the laser generating system 500, the control system 600 and the online monitoring system 700 are fully installed on the bed assembly 800.
[0038] 2. The workpiece to be processed is placed on the tooling 16 of the tooling assembly 200. The tooling 16 can automatically or manually position and clamp the workpiece 15. The tooling 16 selects materials to protect the material of the workpiece 15 itself.
[0039] 3. The control system 600 communicates with the carrying platform 100. The servo motor 1 drives the X1 axis to move left and right along the guide rail 1 through the coupling 1 2. The servo motor 2 7 drives the Y1 axis 5 to move forward and backward along the guide rail 2 8 through the coupling 2 6. The servo motor 3 14 drives the Z1 axis 12 to move along the guide rail 3 11 through the coupling 3 13. The guide rail 3 11 is equipped with a self-centering hinge 9 above. The hinge 9 is connected to the table 10 above. The table 10 rises and falls through the cooperation of the Z1 axis and the hinge 9. The pressure sensor 10A performs weight detection on the workpiece 15 and the tooling 16 above the table. When abnormal, it communicates with the control system 600 to issue an alarm.
[0040] 4. The workpiece 15 and the tooling 16 are adjusted in position following the table 10, and moved to the working area of the visual positioning system 300 for positioning processing. The workpiece 15 and the tooling 16 are transmitted to the control card and the control system 600 via the image processor, and then transmitted to the carrier platform 300 and the dynamic focusing galvanometer 400 via the control card by the control system 600. The multi-axis inside the carrier platform 100 obeys the instructions of the control system 600 to transfer the workpiece 15 to the focal working area of the dynamic focusing galvanometer 400, and establish a processing coordinate system and path control points for processing the surface of the workpiece 15. The Bezier curve is defined based on the starting point, anchor point and control point. The scoring curve is fitted with high precision by fine-tuning the control point coordinates, thereby determining the scoring path and transmitting it to the control system 600 through communication.
[0041] 5. The dynamic focusing galvanometer 400 is composed of an X2-axis swing mirror 17, a Y2-axis swing mirror 18, a Z2 axis and a sensor 20 that cooperate with each other to achieve the spatial position change of the focus. The galvanometer power supply 21 supplies energy to the dynamic focusing galvanometer, and the transmission system 22 communicates with the control system 600 in real time.
[0042] 6. The laser power supply 26 in the laser generating system 500 communicates with the control system 600 to provide energy and data for the laser generator 25. The cooling system 27 and the dehumidification system 28 control the working environment of the laser generator 25. The beam expander 23 and the sensing device 24 provide a stable light source for the dynamic focusing galvanometer 400.
[0043] 7. The 3D model data is written into the control system 600. The control system 600 communicates with the carrier platform 100 and the visual positioning system to locate the coordinates of the processing starting point of the workpiece 15. After completion, the carrier platform 100 transports the workpiece 15 to the working area of the dynamic focusing galvanometer 400, focuses according to the processing starting point of the workpiece 15, turns on the laser generating system 500, and the control system 600 directs the movement of each part to perform engraving according to the fitting path until the engraving operation is completed.
[0044] 8. The laser vapors generated during the laser scribing process are discharged in real time through the atmosphere purification system.
[0045] The above-described embodiment only expresses one implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several changes, adjustments and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.
Claims
1. An ultrashort pulse laser processing method along a Bezier curve fitting path, characterized in that: An ultrashort pulse laser is projected onto the surface of a workpiece to be processed through a dynamic focusing galvanometer. The workpiece to be processed is supported by a carrying platform below and subjected to multi-axis auxiliary motion. The scanning trajectory of the laser spot on the surface of the workpiece to be processed is made to coincide with a predetermined processing path through the dual coordinate system linkage of the focusing galvanometer and the carrying platform. The predetermined processing path is determined by a starting point, an anchor point and two intermediate control points. By fitting the predetermined processing path with a Bezier curve, the real-time vector of the path point is determined, thereby realizing ultrashort pulse laser scribing of various morphological curves on the surface of the workpiece to be processed.
2. The method for ultrashort pulse laser processing along a Bezier curve fitting path according to claim 1, characterized in that: The Bezier curve is generated by substituting the selected N-1 control points into the N-order Bezier curve formula and then performing recursive calculation.
3. An ultrashort pulse laser processing equipment along a Bezier curve fitting path, the equipment adopts an ultrashort pulse laser processing method along a Bezier curve fitting path according to any one of claims 1 to 2, characterized in that: Including the carrying platform, visual positioning system, control system, dynamic focusing galvanometer, line engraving processing area, atmosphere guarantee system, online monitoring system, laser generation system; The bearing platform is mainly composed of a servo motor, a coupling, a guide rail, a hinge, a servo axis X1, a servo axis Y1, a servo axis Z1, a protective device, a power supply A, a sensor, a work surface and a tooling; the servo motor moves the servo axis X1, the servo axis Y1 and the servo axis Z1 through the coupling, and the hinge moves synchronously; the workpiece is fixed on the work surface by the tooling, and the workpiece and the tooling move with the work surface; The visual positioning system mainly includes a high-speed high-definition camera, an image processing system, and a servo drive. The camera samples the workpiece on the stage, cooperates with the image processing system and the servo drive to achieve the establishment of a processing coordinate system for the workpiece surface, and transmits it to the control system through communication; The control system includes a human-machine interface and a control card, which can display parameters such as the drive shaft, laser output power, temperature and humidity, and processing spot diameter on the human-machine interface; the control card mainly communicates, processes, converts, and operates information of the servo motor, drive, dynamic focusing galvanometer, laser, power supply, atmosphere purification system, and online monitoring system; The dynamic focusing galvanometer is composed of an X2-axis swing mirror, a Y2-axis swing mirror, a Z2-axis drive, a sensor, a data transmission system, and a power supply; the X2-axis swing mirror, the Y2-axis swing mirror, the Z2-axis drive, and the sensor cooperate to realize the spatial change of the laser focus, and the control system provides a processing coordinate system converted by the visual positioning system for data simulation processing; The line engraving processing area is equipped with special tooling to achieve rapid replacement of workpieces of different shapes, consistent interfaces, convenient coordinate point calculation, and ensure rapid conversion of processing programs; The atmosphere guarantee system is mainly composed of a dust removal system, etc. The dust removal system collects and filters the materials vaporized by the laser during the processing, thus realizing a green processing environment. The online monitoring system: a pressure sensor device is installed on the load-bearing platform, motion sensors are installed on each axis of the galvanometer, and a smoke sensor is installed on the atmosphere purification system, so as to realize real-time monitoring of the status of subsystems such as the load of the load-bearing platform, the light output of the galvanometer, and the atmosphere purification system, and display the working status parameters on the human-machine operation interface and give early warning. The laser generation system is mainly composed of a laser, a laser power supply, a cooling device, a dehumidification device, etc. The laser provides a reliable ultrashort pulse laser light source, so that it can directly or indirectly (beam expander) provide a light spot that meets the controllable range of the dynamic focusing galvanometer; the laser power supply provides energy, data and other information to the laser, establishes communication with the control card, and meets the surface parameter requirements of the processed workpiece; the cooling device mainly guarantees the working temperature of the high-precision optical components inside the laser generator, so that it can perform tasks within the allowable parameter range; the dehumidification device mainly provides a strong working environment guarantee for the laser generation system, so that the dew point temperature is controllable and meets the requirements of ultrafast laser pulse line micromachining workpieces.
4. The ultrashort pulse laser processing equipment along the Bezier curve fitting path according to claim 3, characterized in that: The control system can automatically perform curve path point vector fitting on a predetermined line engraving path according to the digital model geometric features of the space curved surface to be processed, thereby realizing continuous line engraving micro-processing of curves of different shapes.
5. The ultrashort pulse laser processing equipment along the Bezier curve fitting path according to claim 3, characterized in that: The control system can realize automatic calling and operation of laser line engraving process parameters.
6. The ultrashort pulse laser processing equipment along the Bezier curve fitting path according to claim 3, characterized in that: During the wire-engraving micromachining process, the atmosphere guarantee system can timely remove the gasification residues and dust particles generated when the laser removes the material, thereby improving the quality of the wire-engraving micromachining.
7. The ultrashort pulse laser processing equipment along the Bezier curve fitting path according to claim 3, characterized in that: The load-bearing platform is equipped with a pressure sensor, which can monitor the load status of the load-bearing platform and automatically adjust the opening time and safety lock of the laser pulse according to the load status.