Method and processing system for improving verticality of micro-grooves processed by femtosecond laser

Abstract

The present invention belongs to the field of laser processing, and specifically relates to a method and processing system for improving the verticality of microgrooves processed by femtosecond laser. This method achieves the goal of processing the surface of semiconductor materials and glass materials by first covering the target surface with a cover plate and a buffer layer material of a specific material and thickness, and then performing femtosecond laser processing, thereby achieving a microgroove array with higher processing quality, narrower microgroove width and higher verticality. The solution also combines a large amount of real experimental data to build a process database, thereby achieving the goal of cutting or surface treatment of any material. The optimal processing parameters can be quickly determined in combination with the working conditions, thereby achieving a simultaneous improvement in processing efficiency and processing quality. The solution of the present invention can effectively overcome the problems of insufficient resolution and low processing quality in traditional femtosecond laser processing technology in certain scenarios.

Description

Technical Field

[0001] The present invention belongs to the field of laser processing, and in particular relates to a method for improving the verticality of micro-grooves processed by femtosecond laser, a laser cutting method and a corresponding femtosecond laser processing system. Background Art

[0002] Femtosecond laser direct writing (Femtosecond laser direct writing) is an extremely high-precision micromachining method that focuses light energy onto a tiny area through optical path design, processing the material surface with femtosecond pulse widths. This technology, with its advantages such as high precision and low heat-affected zone, holds great promise for micromachining applications, including in microelectronics manufacturing, biomedical device processing, and optical component fabrication. Furthermore, Femtosecond laser processing has been extensively validated and is suitable for micro- and nano-machining of a wide range of materials, such as polymer-based animal vascular stents, metal micropore arrays, high-aspect-ratio micropores in glass, and ceramic microstructures.

[0003] Patterned materials and molded structures demonstrate significant value in numerous industrial applications at the micro- and nanoscale, making micro- and nanofabrication technologies a key research area. Advanced technologies, in particular, capable of fabricating structures with resolutions exceeding the optical diffraction limit, not only demonstrate the potential for precision design and technological innovation but also highlight their importance in driving cutting-edge applications. With the rapid development of industries such as consumer electronics, integrated electronics, and photovoltaics, transparent, hard, and brittle materials such as glass have been widely used in the manufacture of mobile phones, laptops, and other electronic devices. During the production of these products, glass substrates often require high-precision cutting according to specific requirements. Therefore, research on high-quality and efficient cutting processes for quartz glass is of great practical significance.

[0004] Traditional cutting methods primarily rely on diamond cutting wheels, but their cutting quality is poor. Non-traditional cutting techniques include water jet and laser processing, with crack control being widely used in glass laser cutting. This method uses a laser beam to create a scratch on the glass surface, then guides the glass along a predetermined cutting path through subsequent mechanical or thermal stress. However, crack control has strict requirements on the process parameters for the scratch depth and the cracking process, resulting in complex processing, low yield, and the need for additional post-cutting processing.

[0005] Because quartz glass has a high ablation threshold, picosecond laser cutting has relatively low peak power and a low material removal rate per scan, requiring multiple repeated scans to complete the cut. This significantly reduces processing efficiency. In contrast, femtosecond lasers are attracting increasing attention due to their high precision, high efficiency, and ease of implementation. Therefore, developing a low-cost, easy-to-use method for cutting quartz glass would be a significant breakthrough in this field. Summary of the Invention

[0006] In order to solve the problem that it is difficult in the prior art to process groove structures that meet the verticality requirements on the surfaces of materials such as glass and semiconductors, the present invention provides a method for improving the verticality of microgrooves processed by femtosecond laser and a corresponding femtosecond laser processing system.

[0007] The technical solution provided by the present invention is:

[0008] A method for improving the verticality of microgrooves processed by femtosecond laser, comprising:

[0009] The material and target depth of the target to be processed are used as working condition requirements. Based on the working condition requirements, a process database is queried to obtain several candidate process combinations that meet the processing requirements. Each process combination consists of a set of values ​​for cover material, cover thickness, laser power, and number of scans.

[0010] A buffer layer of material is applied to the cleaned surface of the target to be processed. A cover plate of the appropriate specifications is then placed over the buffer layer based on the selected process combination. Finally, the cover plate and target assembly are secured, and a femtosecond laser is directed from one side of the cover plate according to preset processing parameters to create microgrooves of the specified structure on the target surface.

[0011] Among them, the process database is established in combination with real experimental data, which is used to characterize the maximum depth of micro-grooves that meet the verticality requirements when the femtosecond laser processing system uses any specified laser power and number of scans to process the target surface to be processed with a specified material covered with a cover plate of any material and thickness.

[0012] As a further improvement of the present invention, the buffer layer material is a substance whose heat resistance temperature, thermal expansion coefficient and light absorption performance meet preset thresholds and can be specifically removed by any chemical or physical means.

[0013] As a further improvement of the present invention, the buffer layer material adopts organic adhesive or polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyimide (PI), polyamide imide (PAI), polytetrafluoroethylene (PTEE) film coated with glue on the surface.

[0014] As a further improvement of the present invention, after the femtosecond laser processing is completed, the buffer layer material between the cover plate and the target to be processed is removed by specified chemical or physical means, and the target to be processed is cleaned and dried to obtain a product with specified microgrooves.

[0015] The method of improving the verticality of micro-grooves processed by femtosecond laser according to the present invention is applicable to the materials of the target to be processed including glass, single crystal silicon, polycrystalline silicon or other semiconductor materials.

[0016] As a further improvement of the present invention, the material of the cover plate includes quartz glass, high-aluminum glass, high-borosilicate glass, sapphire glass, etc.

[0017] As a further improvement of the present invention, for any specified working condition requirement, all process combinations contained in the process database that are consistent with the target material to be processed and can produce a microgroove with a maximum depth greater than the target depth can be used as candidate process parameters for the current working condition requirement.

[0018] As a further improvement of the present invention, the method for constructing a process database includes the following steps:

[0019] S1: Preset several candidate values ​​of the material of the target to be processed and the cover, the thickness of the cover, the laser power and the number of scans as the feasible domain of each parameter.

[0020] S2: Design an experimental plan that can cover all feasible regions of each parameter according to the orthogonal experimental method.

[0021] S3: Execute each experimental case in the experimental plan, cover the buffer layer and the cover plate on the target to be processed, and use the femtosecond laser processing system to process the target to be processed covered with the cover plate according to the preset processing parameters. After the processing is completed, measure and record the maximum depth of the micro-groove formed on the target to be processed that meets the verticality requirements.

[0022] S4: Organize the experimental data, and use the material of the processing target, cover material, cover thickness, laser power, number of scans, and micro-groove depth corresponding to each group of experiments as a piece of process data, and then obtain a process database containing multiple pieces of process data.

[0023] The present invention also includes a laser cutting method, which includes taking the thickness of the workpiece to be cut as the target depth and cutting the workpiece to be cut using the aforementioned method of improving the verticality of the micro-grooves processed by the femtosecond laser.

[0024] The present invention also includes a femtosecond laser processing system, comprising a device body and a host computer. The device body comprises a femtosecond laser, a reflector, an attenuation plate, an optical shutter, a scanning galvanometer, and a three-dimensional motion stage. The three-dimensional motion stage is used to place the target to be processed; the device body is used to complete the processing task according to received control instructions.

[0025] The host computer is electrically connected to the device body; it contains a built-in process database, as described in the aforementioned method for improving the verticality of microgrooves processed by femtosecond laser machining. The host computer is used to obtain the working condition requirements for each machining task and then, in conjunction with the industrial control computer, queries the process database to obtain candidate process combinations. The host computer automatically selects one of the process combinations based on preset rules or selects a user-specified process combination through human-computer interaction. The host computer then issues machining control instructions to the device body based on the parameter values ​​contained in the selected process combination.

[0026] As a further improvement of the present invention, the strategy for the host computer to automatically select the process combination is:

[0027] First, the cover material and cover thickness corresponding to the cover with the largest surplus in the spare parts library are screened out from the candidate process combinations; then, the process combination with the best power consumption among the remaining candidate process combinations is selected based on the laser power and the number of scans.

[0028] The technical solution provided by the present invention has the following beneficial effects:

[0029] The method provided by this invention, which involves first bonding a glass cover plate and a buffer layer material to the target surface before performing femtosecond laser processing, significantly improves femtosecond laser processing resolution and quality at a very low cost. This method not only enables the production of narrower, more linear microgrooves, but also provides a good foundation for subsequent cutting of high-precision glass components with even, straighter edges and greater verticality.

[0030] Because glass components are widely used in optics, electronics, and micromechanics, such as optical lenses, beam splitters, and waveguides, this technology has broad application prospects and enormous commercial potential. With further process optimization and expansion, this method is expected to play an even greater role in high-precision glass processing, providing a reliable solution for the fabrication of complex structures. For example, it could be applied to the fabrication of optical components, microfluidic chips, micro-optical structures, and complex micromechanical assemblies, thereby enhancing the functional performance and reliability of these devices.

[0031] By optimizing the material coverage strategy, the proposed solution can further effectively improve processing quality, laying a technical foundation for the precision manufacturing of complex structures. Furthermore, this improved process solution is highly scalable and applicable to the processing needs of a variety of materials and structures, expanding the application potential of femtosecond lasers in advanced manufacturing.

[0032] Furthermore, the research findings of this paper provide new reference directions for optimizing femtosecond laser processing parameters. By rationally adjusting the number of scans, laser power, processing speed, and the thickness and type of the overlay material, more efficient and high-quality processing solutions can be further explored. This not only provides the possibility of reducing processing costs and improving processing efficiency, but also opens up new possibilities for achieving precise control of complex morphologies and functional structures. Therefore, this result has important scientific value and practical application prospects in the field of micro-nano processing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of a femtosecond laser processing solution for adding a glass cover plate and a buffer layer in Example 1 of the present invention.

[0034] Figure 2 This is a flowchart of the steps of the method for improving the verticality of microgrooves processed by femtosecond laser provided in Example 1 of the present invention.

[0035] Figure 3 This is a flowchart of the steps of the method for constructing a process database in Example 1 of the present invention.

[0036] Figure 4 This is a schematic diagram of the femtosecond laser processing system provided in Example 1 of the present invention.

[0037] Figure 5 To verify the curve of the change of micro-groove width with the number of scans processed by the two schemes in the experiment.

[0038] Figure 6 To verify the curve of the change of micro-groove depth with the number of scans processed by the two schemes in the experiment.

[0039] Figure 7 To verify the change curve of the verticality of the micro-grooves processed by the two schemes in the experiment with the number of scans.

[0040] Figure 8 This is a schematic diagram showing how the present invention can optimize micro-groove quality during machining.

[0041] Figure 9 To verify the microscopic morphology of the glass samples in the four different schemes after multiple repeated scanning. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] Example 1

[0044] Femtosecond laser processing is a common technique for surface topography or cutting of semiconductor and glass materials. However, in some precision machining scenarios, the grooves produced by conventional femtosecond laser processing often have a V-shaped structure, wide at the top and narrow at the bottom. Furthermore, the flying slag phenomenon during femtosecond laser processing and its impact on the thermal stress distribution of the material can also cause structural defects such as contamination and cracks on the target surface after cutting or processing. These phenomena limit the application of femtosecond laser processing in related fields.

[0045] In order to solve the problem that the femtosecond laser processing system is difficult to adapt to such processing scenarios, the technicians of this embodiment found in their research that: Figure 1As shown in the figure, when a high-melting-point glass material is superimposed on the target material to be processed as a cover plate, the femtosecond laser will first melt through the upper cover plate before processing the target material below. The laser modulation effect generated by the melted cover plate enables the femtosecond laser to form a more vertical groove on the surface of the target material, improving the slope of the cutting edge and significantly improving the processing effect. Among them, the cover plate material is generally preferably a material with a high melting point and high light transmittance, such as quartz glass, high-aluminum glass, high-borosilicate glass, sapphire glass, etc.

[0046] Furthermore, during research, researchers working on this embodiment discovered that adding a buffer layer composed of an organic material between the cover plate and the target material effectively fills the gap between them, forming a protective layer covering the upper surface of the target material, thereby preventing contamination of the target material surface by flying slag during machining. Furthermore, the buffer layer absorbs the mutual stress between the target material and the cover plate caused by thermal expansion during machining, thereby reducing stress-induced cracks on the surface and within the target material.

[0047] Based on the above success, the technicians of this embodiment further systematically analyzed several factors that affect the verticality and processing depth of the grooves on the target material, and then designed a new processing technology that can be applied to different processing conditions and can process microgroove arrays with higher processing quality, narrower microgroove widths, and higher verticality on the surfaces of semiconductor materials and glass materials. Specifically, this embodiment first provides a method for improving the verticality of microgrooves processed by femtosecond laser, such as Figure 2 As shown, the method includes:

[0048] 1. Query and determine processing parameters

[0049] The target material α and target depth h are used as working condition requirements. Based on these working condition requirements, a process database is queried to obtain several candidate process combinations that meet the processing requirements. Each process combination consists of a set of values ​​for the cover material β, cover thickness d, laser power W, and number of scans N.

[0050] In the scheme of this embodiment, the processing target is the material that needs to be grooved, cut or surface-topographically processed. The scheme of this embodiment can be applied to improve the femtosecond laser processing effect of processing targets of various high-melting-point materials, such as glass, single-crystal silicon, polycrystalline silicon, gallium nitride and other semiconductor materials, etc. The target depth refers to the depth of the groove that meets the required verticality during the processing. Of course, when used to cut the processing target, the target depth here is actually equal to the thickness of the target material. It should be emphasized that the maximum target depth that can be achieved during the processing of each type of material has an upper limit, and the user should select the process within the range supported by the system processing capabilities.

[0051] This embodiment queries a process database based on working condition requirements to obtain processing parameters that meet these requirements. The process database, established using real-world experimental data, characterizes the maximum microgroove depth that can be achieved by a femtosecond laser processing system, meeting perpendicularity requirements, using any specified laser power and scan count, on a target surface of a specified material covered with a cover plate of any material and thickness.

[0052] Specifically, the process database of this embodiment is a data set composed of a large number of six-element arrays as basic elements. The data format of each six-element array is {α, β, d, W, N, h}. This six-element array is used to represent: when the user covers a processing target made of material α with a cover plate of material β and thickness d, and sets the laser power to W, the depth h of the groove that can be obtained on the processing target to meet the verticality requirements after repeatedly scanning the specified area N times.

[0053] It should be further explained that for any specific working condition where the values ​​of α and h are known, there may be more than one combination of processing parameters of β, d, W, and N that can achieve the corresponding processing effect. Therefore, the query results are usually presented in the form of multiple candidate process combinations, and technicians can select a more appropriate process combination based on the actual situation.

[0054] Furthermore, in a process database with limited data samples, there may not be a candidate process combination (i.e., a sextuple) that is exactly the same as the desired target depth h. In this case, for any specified working condition requirement, all process combinations in the process database that match the target material to be processed and can produce a microgroove with a maximum depth greater than the target depth can be used as candidate process parameters for the current working condition requirement. For example, the target depth to be achieved in a certain actual working condition requirement is 0.03mm, but the process combinations with matching materials in the process data set do not include a data set with d=0.03mm. In this case, if there is any process combination with matching materials and d>0.03mm, this process combination can be used as a candidate process combination. The inherent mechanism of this process selection strategy is that for each process parameter, it reflects the maximum depth of the microgroove that can be produced under the current processing conditions to meet the verticality requirements. When the number of repeated scans N in the process parameter is reduced, the depth of the corresponding microgroove that meets the verticality requirements will also be reduced. Therefore, each process parameter can adapt to working conditions with smaller actual d values.

[0055] 2. Process preparation and implementation

[0056] A buffer layer of material is applied to the cleaned surface of the target to be processed. A cover plate of the appropriate specifications is then placed over the buffer layer based on the selected process combination. Finally, the cover plate and target assembly are secured, and a femtosecond laser is directed from one side of the cover plate according to preset processing parameters to create microgrooves of the specified structure on the target surface.

[0057] In the solution of this embodiment, the buffer layer material plays a role primarily during the femtosecond laser processing process. After the processing is completed, the buffer layer material should be peeled off from the processing target surface. Therefore, based on the above analysis of the role of the buffer material, it can be seen that the buffer layer material is preferably a substance whose heat resistance temperature, thermal expansion coefficient, and light absorption performance meet the preset thresholds and can be specifically removed by any chemical or physical means. Such as organic adhesives or polyphenylene sulfide, polyphenylene ether, polyimide, polyamide imide, or polytetrafluoroethylene film coated with glue.

[0058] In this embodiment, a specific material is selected as the buffer layer primarily to facilitate the use of specific chemical or physical methods to remove the buffer layer material between the cover plate and the target after processing is complete, while also preventing damage to the target. For example, when both the target and the cover plate are made of glass, an organic adhesive can be used as the buffer layer material. In this case, after femtosecond laser processing is complete, the buffer layer material between the target and the cover plate can be dissolved away using an organic solvent. Finally, the target can be cleaned and dried to obtain a product with the specified microgrooves.

[0059] In the method for improving the verticality of microgrooves processed by femtosecond laser provided in this embodiment, the process database is a key tool for achieving accurate selection of process parameters and is also one of the core advantages of the solution of this embodiment. Specifically, Figure 3 As shown, the method for constructing the process database includes the following steps:

[0060] S1: Preset several candidate values ​​of the material of the target to be processed and the cover, the thickness of the cover, the laser power and the number of scans as the feasible domain of each parameter.

[0061] S2: Design an experimental plan that can cover all feasible regions of each parameter according to the orthogonal experimental method.

[0062] S3: Execute each experimental case in the experimental plan, cover the buffer layer and the cover plate on the target to be processed, and use the femtosecond laser processing system to process the target to be processed covered with the cover plate according to the preset processing parameters. After the processing is completed, measure and record the maximum depth of the micro-groove formed on the target to be processed that meets the verticality requirements.

[0063] S4: Organize the experimental data, and use the material of the processing target, cover material, cover thickness, laser power, number of scans, and micro-groove depth corresponding to each group of experiments as a piece of process data, and then obtain a process database containing multiple pieces of process data.

[0064] Finally, in combination with the method for improving the verticality of microgrooves processed by femtosecond laser provided above, this embodiment further provides a laser cutting method, which includes taking the thickness of the workpiece to be cut as the target depth, and using the method for improving the verticality of microgrooves processed by femtosecond laser as mentioned above to cut the workpiece to be cut.

[0065] In summary, the technology provided in this embodiment provides an excellent foundation for the cutting and fine processing of microdevices. After preliminary processing, the edges of the quartz glass are smoother and the surface is smoother, greatly improving the overall quality of the microdevices. This innovative processing method not only reduces processing difficulty but also improves production efficiency and product consistency, providing important technical support for further applications in fields such as high-precision optical devices and microfluidic chips.

[0066] Example 2

[0067] Based on the solution of Example 1, this embodiment further provides a femtosecond laser processing system, which includes a device body and a host computer. Figure 4As shown, the device body consists of a femtosecond laser, a reflector, an attenuation plate, an optical gate, a scanning galvanometer and a three-dimensional moving stage. Among them, the pulsed laser is emitted from the amplifier stage outlet of the femtosecond laser and is decomposed into several laser beams with uniform energy by a laser beam splitter. The split laser is reflected to the attenuation plate by a reflector, and the attenuation plate is used to adjust the energy of the incident light beam. The adjusted laser beam enters the reflector through the optical gate and is finally focused on the surface of the sample to be processed through the scanning galvanometer. The on and off of the entire optical path is controlled by the optical gate, and the user can manually operate the controller to realize the on and off adjustment of the optical path. The three-dimensional moving stage is used to place the target to be processed; in the system of this embodiment, focusing operations and three-dimensional movement of the processing target can be realized through manual and program control. In actual work, the device body of this embodiment is used to complete the processing task according to the received control instructions.

[0068] The host computer is electrically connected to the device body; the host computer has a built-in process database, as described in the aforementioned method for improving the verticality of microgrooves processed by femtosecond lasers. The host computer is used to obtain the working condition requirements of each processing task, and then, in conjunction with the industrial control computer, queries the process database to obtain candidate process combinations; the host computer automatically selects one of its process combinations based on preset rules or selects a user-specified process combination through human-computer interaction, and then issues control instructions for the processing process to the device body based on the parameter values ​​contained in the selected process combination. Specifically, the host computer's strategy for automatically selecting a process combination is as follows:

[0069] First, the cover material and cover thickness corresponding to the cover with the largest surplus in the spare parts library are screened out from the candidate process combinations; then, the process combination with the best power consumption among the remaining candidate process combinations is selected based on the laser power and the number of scans.

[0070] Verification experiment

[0071] In order to further verify the feasibility of the technical solutions provided in the above embodiments and test the processing effect of the femtosecond laser processing system improved by the above solutions, technicians carried out the following test experiments.

[0072] 1. The influence of the cover plate on the structural characteristics of the machined micro-grooves

[0073] This experiment first compares the parameters of the microgrooves produced by the improved solution of attaching the cover plate provided by the present invention with those of the traditional solution of directly processing without attaching the cover plate, in order to verify the influence of the two solutions on the morphology of the microgrooves finally processed by the femtosecond laser processing system.

[0074] The experimental process involved thoroughly cleaning the quartz glass with alcohol to remove surface contaminants. The cleaned quartz glass was then dried in a vacuum drying oven to ensure no residual moisture remained on the surface. After drying, 60μm-thick scotch tape was applied to the quartz glass surface, followed by a 160μm-thick thin glass layer. This layered structure provided a stable substrate for femtosecond laser microgrooving.

[0075] At the same time, the CSmark processing software was opened on the femtosecond laser control computer. A 5mm straight line segment was drawn, and the scanning pitch was set to 0.1mm. This graph provided a reference for the subsequent microgrooving process. The femtosecond laser processing system was then set to a scanning speed of 5mm / s and a scanning power of 200mW. To investigate the effect of the number of scans on the depth and width of the microgrooves, four sets of scan parameters were designed: 150, 200, 250, and 300.

[0076] After completing the parameter settings, click the preview button in the software. A preview straight line segment will appear on the glass surface. By adjusting the three-dimensional moving platform, the laser focus will be accurately positioned on the glass surface. After the focus is aligned, click the "Mark" button to start automatic microgroove processing on the glass. After processing is completed, use a microscope to measure the depth and width of the microgroove and record the measurement data under each set of parameter conditions. And draw the following according to the measurement results. Figure 5 The curves showing the change of micro-groove width processed by the two schemes with the number of scans are shown in FIG. Figure 6 The curves showing the change of micro-groove depth with the number of scans produced by the two schemes are shown in FIG. Figure 7 The curves shown here represent the change of the verticality of the microgrooves processed by the two schemes with the number of scans.

[0077] First, combine Figure 5 and Figure 6 The data shows that the width and depth of the microgrooves on the quartz glass surface increase with increasing femtosecond laser scan times. This phenomenon can be attributed to the cumulative removal effect of repeated laser action on the material. However, when a thin layer of glass is attached to the quartz glass surface, the rate and amount of change in the depth and width of the microgrooves produced at different scan times are significantly reduced; theoretically, this should significantly improve the verticality of the produced microgrooves.

[0078] Further observation Figure 7The data in the study confirms that the verticality of the microgrooves is significantly improved when thin glass is bonded. This demonstrates that the method provided by the present invention can significantly reduce slopes, offsets, jitter, and irregularities that may occur during processing, thereby achieving higher-quality processing results. This improvement is particularly significant for optical components that require extremely high edge precision.

[0079] Based on the above results, we can combine Figure 8 Analyze the inherent principle of the present invention to achieve the above technical effects:

[0080] In this embodiment, after attaching thin glass as a cover plate, the laser's range of action is more concentrated, thereby improving processing resolution. Furthermore, under the influence of this concentration effect, under the same scanning conditions of the femtosecond laser processing system, the system can process narrower microgrooves. Furthermore, the introduction of the cover plate and buffer layer materials in the scheme of the present invention optimizes the transmission and action mode of laser energy. The thin glass may have played a role in stabilizing the laser optical path, reducing scattering, and improving the heat-affected zone, thereby making the edges of the microgrooves more neat and smooth.

[0081] 2. Influence of the buffer layer on the structural characteristics of the machined microgrooves

[0082] This experiment further studies the effect of the use of a buffer layer on the morphology of the microgrooves ultimately processed by the femtosecond laser processing system. Four control groups were set up in this experiment, among which control group 1 did not stick any material on the surface of the glass to be processed, control group 2 coated a layer of 40μm thick organic adhesive on the surface of the glass to be processed; control group 3 pasted a 160μm thick glass cover on the surface of the glass to be processed; control group 4 first coated the surface of the glass to be processed with an organic adhesive, and then covered it with a glass cover, with an overall thickness of 160μm; finally, the samples of the four control groups were scanned repeatedly 200, 300, and 400 times according to the parameters of power 300mW and speed 10mm / s. The final processing effect is as follows Figure 9 shown. Figure 9 The four horizontal columns reflect the processing effects of samples in different control groups, and the three vertical rows in each column reflect the processing effects of the same sample under different scanning times.

[0083] analyze Figure 9The data show that, under the same number of scans, the microgrooved structures formed by femtosecond laser processing can be differentiated by coating the quartz glass surface with different materials. The choice of coating material significantly affects the thermal impact and surface quality of the processed area. Compared with the other three samples, the surface morphology produced by the combination of a glass cover plate and a buffer layer on the quartz glass surface exhibits significant advantages, with significantly less thermal damage and processing residue in the microgrooved area, sharper edges, and higher surface quality. This technical effect is likely due to the following: on the one hand, the combined coating strategy of thin glass and a buffer layer significantly improves the quality of the processed surface by reducing the thermal effects of direct interaction between the laser and the material; on the other hand, compared to the treatment of a directly exposed quartz glass surface or a single coating material, the combined coating of the glass cover plate and the buffer layer provides a more stable processing environment, reducing spatter, heat accumulation, and potential microcracks or debris generated during laser action. Therefore, the improvements proposed in this invention not only significantly improve the quality of the processed surface but also provide a new path for high-precision, low-pollution microstructure processing.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for improving the verticality of microgrooves processed by femtosecond laser, characterized in that: It includes: The material and target depth of the target to be processed are used as working condition requirements. A process database is queried based on the working condition requirements to obtain several candidate process combinations that meet the processing requirements. Each process combination consists of a set of values ​​for cover material, cover thickness, laser power, and number of scans. A buffer layer material is applied to the processing area of ​​the cleaned target surface, and then a cover plate of corresponding specifications is placed on top of the buffer layer according to the selected process combination. Finally, the combination of the cover plate and the target surface is fixed, and a femtosecond laser is incident from one side of the cover plate according to preset processing parameters to achieve micro-grooves of the specified structure on the target surface. The process database is established in combination with real experimental data and is used to characterize the maximum depth of microgrooves that meet verticality requirements when a femtosecond laser processing system uses any specified laser power and number of scans to process a target surface to be processed of a specified material covered with a cover plate of any material and thickness.

2. The method for improving the verticality of microgrooves processed by femtosecond laser according to claim 1, characterized in that: The buffer layer material is a substance whose heat resistance temperature, thermal expansion coefficient and light absorption performance meet preset thresholds and can be specifically removed by any chemical or physical means.

3. The method for improving the verticality of microgrooves processed by femtosecond laser according to claim 2, characterized in that: The buffer layer material is made of organic adhesive or polyphenylene sulfide, polyphenylene ether, polyimide, polyamide imide, or polytetrafluoroethylene film with glue coated on the surface.

4. The method for improving the verticality of microgrooves processed by femtosecond laser according to claim 2, characterized in that: After the femtosecond laser processing is completed, the buffer layer material between the cover plate and the target to be processed is removed by specified chemical or physical means, and the target to be processed is cleaned and dried to obtain a product with specified microgrooves.

5. The method for improving the verticality of microgrooves processed by femtosecond laser according to claim 1, wherein: The materials of the target to be processed include glass, single crystal silicon, polycrystalline silicon or other semiconductor materials; and / or The material of the cover plate includes quartz glass, high aluminum glass, high borosilicate glass, and sapphire glass.

6. The method for improving the verticality of microgrooves processed by femtosecond laser according to claim 1, wherein: For any specified working condition requirement, all process combinations contained in the process database that are consistent with the target material to be processed and can produce microgrooves with a maximum depth greater than the target depth can be used as candidate process parameters for the current working condition requirement.

7. The method for improving the verticality of microgrooves processed by femtosecond laser according to claim 1, wherein: The method for constructing the process database comprises the following steps: S1: Preset several candidate values ​​of the material of the target to be processed and the cover, the thickness of the cover, the laser power and the number of scans as the feasible domain of each parameter; S2: Design an experimental plan that can cover all feasible regions of each parameter according to the orthogonal experimental method; S3: Execute each experimental case in the experimental plan, cover the target with a buffer layer and a cover plate, and process the target covered with the cover plate using a femtosecond laser processing system according to preset processing parameters. After processing, measure and record the maximum depth of the micro-grooves formed on the target that meet the verticality requirements; S4: Organize the experimental data, and use the material of the processing target, cover material, cover thickness, laser power, number of scans, and micro-groove depth corresponding to each group of experiments as a piece of process data, and then obtain a process database containing multiple pieces of process data.

8. A laser cutting method, characterized in that: It includes: The thickness of the workpiece to be cut is used as the target depth, and the workpiece to be cut is cut using the method for improving the verticality of micro-grooves processed by femtosecond laser according to any one of claims 1 to 7.

9. A femtosecond laser processing system, characterized in that: It includes: The device body is composed of a femtosecond laser, a reflector, an attenuation plate, an optical shutter, a scanning galvanometer, and a three-dimensional moving stage; the three-dimensional moving stage is used to place the target to be processed; the device body is used to complete the processing task according to the received control instructions; A host computer is electrically connected to the device body; the host computer has a built-in process database for the method for improving the verticality of microgrooves processed by femtosecond laser according to any one of claims 1 to 7; the host computer is used to obtain the working condition requirements of each processing task, and then query the process database in combination with the industrial computer to obtain a candidate process combination; the host computer automatically selects one of its process combinations according to preset rules or selects a user-specified process combination through human-computer interaction, and then issues control instructions for the processing process to the device body according to the parameter values ​​contained in the selected process combination.

10. The femtosecond laser processing system according to claim 9, wherein: The strategy of the host computer to automatically select the process combination is: First, the cover material and cover thickness corresponding to the cover with the largest surplus in the spare parts library are screened out from the candidate process combinations; then, the process combination with the best power consumption among the remaining candidate process combinations is selected based on the laser power and the number of scans.

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