Method for preparing glass microporous structure by combining wet etching with femtosecond laser double pulse
By combining wet etching with femtosecond laser dual-pulse method, blind holes are formed and etched on both sides of quartz glass, which solves the problem of low aspect ratio of glass micropores in the prior art. It realizes the preparation of micropores with high aspect ratio and low taper, which is suitable for CPO systems and other fields.
Patent Information
- Application Number
- CN202511560060.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-29
- Publication Date
- 2026-03-13
AI Technical Summary
Existing technologies for preparing glass micropores are cumbersome and complex, and the micropore depth-to-diameter ratio is generally low, which cannot meet the application requirements of highly integrated CPO systems.
A method combining wet etching with femtosecond laser dual-pulse etching is used to form through holes with high aspect ratio by creating blind holes on both sides of quartz glass and then performing wet etching. The specific steps include dual-pulse femtosecond laser processing and hydrofluoric acid etching.
It achieves high-precision, low-taper glass micropore fabrication with a depth-to-diameter ratio greater than 10 and a taper of less than 0.01°, making it suitable for micropore applications in CPO systems and other fields. It simplifies the process flow and reduces production costs and quality control difficulties.
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Figure CN121651699A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of laser processing, and particularly relates to the preparation of glass micropores. Background Technology
[0002] In today's rapidly developing digital economy, fields such as cloud computing, artificial intelligence, and supercomputing centers are placing unprecedentedly stringent demands on data transmission rates, bandwidth, and energy efficiency. Traditional electrical interconnect technologies, due to inherent limitations such as bandwidth bottlenecks, transmission latency, and high-frequency losses, are no longer adequate for the needs of next-generation high-performance computing systems. Optical interconnects, with their outstanding advantages of high bandwidth, low latency, and resistance to electromagnetic interference, have become a core solution for overcoming data transmission bottlenecks.
[0003] Co-packaged optics (CPO) technology, as a key implementation path for novel optical interconnects, integrates photonic devices and application-specific integrated circuits (ASICs) onto the same interposer layer using 2.5D or 3D packaging processes. This significantly shortens the physical distance of the photoelectric conversion link, effectively improving data transmission efficiency and system integration, and is widely considered a core technology direction for meeting the high bandwidth requirements of big data centers. The interposer layer, as a key supporting structure of the CPO system, directly determines the RF performance, reliability, and manufacturing cost of the entire system through its material properties.
[0004] While traditional silicon interposers offer mature compatibility with microfabrication processes, their high dielectric constant (εr≈11.7) and loss tangent (tanδ≈0.001) in high-frequency applications lead to severe signal attenuation, significantly limiting the transmission quality of high-frequency signals. In contrast, glass, with its superior overall performance, has become an ideal candidate material for next-generation interposers: First, glass has extremely low dielectric constant (εr≈4-6) and loss tangent (tanδ≈10-4-10-5), which can significantly reduce transmission loss of high-frequency signals and significantly improve the RF performance of the interposer; Second, glass is relatively inexpensive and easier to mass-produce, making it more economical than other high-performance substrate materials such as ceramics and diamond; Third, the coefficient of thermal expansion of glass can be precisely matched through composition control (e.g., close to the coefficient of thermal expansion of silicon ≈3ppm / ℃), effectively alleviating stress caused by thermal mismatch during packaging and improving the long-term stability of the system; In addition, the optical transparency of glass facilitates visual alignment during processing, reducing the integration difficulty between the interposer and the device layer.
[0005] In CPO systems, a large number of high-precision micropore structures need to be fabricated in the glass interposer to realize functions such as optical coupling between fiber arrays and photonic devices, electrical interconnection channels between chips, and heat dissipation pathways. Therefore, the fabrication quality of the micropores (such as aperture accuracy, taper control, hole wall smoothness, and aspect ratio) directly affects the performance of the entire system. Ultrashort pulse laser (femtosecond laser, picosecond laser) processing technology, with its extremely short pulse width (femtosecond level up to 10-15s) and extremely high peak power, can achieve precise micromachining of glass materials through nonlinear absorption effects, and has a very small heat-affected zone, making it one of the mainstream technologies for glass micropore fabrication.
[0006] In recent years, researchers have explored the fabrication of glass micropores using ultrashort pulse lasers: Kim et al. achieved preliminary fabrication of glass micropores using a dual-pulse picosecond laser combined with selective etching; Franz et al. successfully fabricated a micropore structure with a diameter of 125 μm, a cone angle of 7.3 ± 0.1°, and no cracks on a 200 μm thick glass substrate. However, existing technologies still have significant limitations: on the one hand, some process steps are cumbersome and complex, involving multiple parameter calibrations or special pretreatments, making it difficult to meet the needs of large-scale mass production; on the other hand, the aspect ratio of the fabricated micropores is generally low (usually less than 5:1), which cannot adapt to the application requirements of high-integration CPO systems for micropores with large aspect ratios. Therefore, developing a simple, efficient, and reliable method for fabricating glass micropores that meets practical application requirements (high precision, large aspect ratio, and low defects) has become one of the key technological bottlenecks for promoting the industrialization of CPO technology. Summary of the Invention
[0007] To address the technical challenges of small depth-to-diameter and large taper in micropore fabrication, this invention proposes a method for fabricating glass micropore structures using wet etching combined with femtosecond laser dual-pulse etching. This method is simple, and the micropore structure has a high depth-to-diameter ratio and extremely small taper.
[0008] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A method for fabricating glass micropore structures using wet etching combined with femtosecond laser dual-pulse etching, characterized by comprising the following steps: (1) Suspend and fix the quartz glass, so that the double-pulse femtosecond laser passes through the quartz glass and is focused on the outer side of the back of the quartz glass; (2) Move the focus so that the dual-pulse femtosecond laser processes the quartz glass from the back up, forming two blind holes on the upper and lower surfaces of the quartz glass, and forming a modified area between the two blind holes. (3) Wet etching is performed on the quartz glass containing blind holes to etch away the modified areas in the quartz glass, and the upper and lower blind holes are connected to form a through hole.
[0009] The dual-pulse femtosecond laser has a wavelength of 1035 nm, a repetition frequency of 20 kHz-30 kHz, a pulse width of 370 fs, a total laser power of 0.30 W-0.39 W, a dual-pulse interval of 20-30 ns, an energy ratio of 10:7-9, and the energy of the first pulse is greater than that of the second pulse. The exposure time is 900 µs-1100 µs.
[0010] Preferably, during the processing of quartz glass, the scanning speed of the dual-pulse femtosecond laser is 1-2 mm / s, and the moving distance is 1-10 μm.
[0011] The method of suspending and fixing the quartz glass (e.g., by using edge clamps to prevent the laser path from being blocked) ensures that the dual-pulse femtosecond laser penetrates the glass without obstruction and is focused in the back direction.
[0012] The objective lens has a numerical aperture of 0.4-0.8 and a magnification of 20-40 times, and can focus the laser into a spot.
[0013] In step (1), the distance between the focal point of the objective lens and the surface of the quartz glass is 10-30 μm (the focal point can be first positioned on the upper surface of the quartz glass, and the laser can be used to process the quartz glass from bottom to top by setting the initial point to be located outside the lower surface of the quartz glass, and this distance can be automatically adjusted by the system). The lower surface of the quartz glass is etched clean to avoid the formation of a closed hole on the lower surface and ensure the formation of a blind hole.
[0014] The back-side processing of quartz glass, starting from the back and working upwards, allows debris to fall off automatically due to gravity, reducing its impact on the next layer. It also prevents the edge of the upper layer's pore structure from affecting the light spot quality due to scattering, thereby reducing the taper of the micropore structure. Furthermore, during back-side processing, the blind holes on the lower surface are deeper than those on the upper surface, resulting in a very small taper. The presence of these blind holes makes it easier for HF acid liquid to enter the pores, thus accelerating the corrosion of the modified area.
[0015] The aforementioned blind holes are formed on both the top and bottom surfaces of the quartz glass, not through holes, and the area between the two blind holes is etched and modified by a dual-pulse femtosecond laser.
[0016] The etching solution used in the wet etching process is hydrofluoric acid, and the etching time is 60-100 minutes.
[0017] The concentration of hydrofluoric acid is 5-10 wt%. Hydrofluoric acid exhibits strong selectivity for laser-modified areas (which are more susceptible to corrosion due to structural defects), precisely removing the modified layer between the upper and lower blind holes, while causing minimal corrosion to the unmodified glass body. The pre-set blind holes provide a rapid penetration channel for hydrofluoric acid, solving the problem of "the etchant being unable to penetrate deep into the layer when there are no blind holes." This accelerates etching efficiency while ensuring uniform corrosion of the hole walls, ultimately forming smooth, low-tapered through holes. Selecting the appropriate concentration and time can thoroughly open up the middle area while avoiding uncontrolled hole diameter due to over-corrosion.
[0018] The thickness of the quartz glass is 200-500 μm.
[0019] The depth-to-diameter ratio of the through hole is 3-15.
[0020] In step (1), the quartz glass needs to be cleaned beforehand. Pre-cleaning of the quartz glass (such as removing surface oil and dust) can reduce scattering interference during laser focusing, ensure the quality of the laser spot, and at the same time avoid impurities from contaminating the modified area, thereby improving the uniformity of subsequent etching. In step (3), the quartz glass after wet etching needs to be cleaned.
[0021] Preferably, ultrasonic cleaning with acetone, alcohol, and deionized water in sequence can thoroughly remove residual hydrofluoric acid (to avoid continuous corrosion), etching products (such as fluorosilicate impurities), and organic contaminants, ensuring the cleanliness of the through-hole walls and providing reliable surface quality for subsequent CPO system applications such as optical coupling and electrical interconnection.
[0022] The beneficial effects of this invention are: (1) The dual-pulse femtosecond laser processing mode is adopted. By synergistic superposition of pulse energy, the absorption efficiency of glass to laser energy is enhanced, avoiding local stress mutation caused by single pulse energy concentration, reducing the generation of cracks during glass micro-hole processing, ensuring the integrity of micro-hole structure and surrounding area, and improving product yield.
[0023] (2) The bottom-up back-focusing processing method effectively avoids the distortion of the focused spot caused by scattering at the edge of the hole structure when the laser passes through the upper surface of the glass, compared with the traditional forward processing method, thus ensuring the uniform distribution of laser energy along the processing path. Most importantly, the inventors discovered that the bottom-up back-focusing processing does not directly form a through hole, but rather forms two blind holes, one above the other. Finally, by adjusting the laser parameters, the range of nonlinear interaction between the laser and the glass can be precisely controlled, ensuring the stable formation of blind hole structures with uniform size and high coaxiality on both the upper and lower surfaces of the glass, laying a good foundation for subsequent etching processes.
[0024] (3) The upper and lower blind hole structure allows the etchant to quickly penetrate into the laser-modified area inside the glass, avoiding the problems of poor penetration and insufficient etching in the modified area that occur without blind holes. This significantly accelerates the etching process and shortens the overall process cycle. At the same time, the etchant can fully contact the hole wall and the intermediate modified area through the blind hole channel, achieving all-round selective etching of the modified area. This not only completely removes the residual modified layer between the upper and lower blind holes, but also further optimizes the smoothness of the hole wall, avoiding local over-etching or incomplete etching, and ensuring the dimensional accuracy and structural consistency of the final through hole.
[0025] (4) The entire preparation process of this invention only includes two core steps: laser processing and wet etching. It requires no complex pretreatment or post-treatment procedures, and all process parameters (laser power, frequency, etching time, etc.) are easily and precisely controlled, adapting to the needs of large-scale mass production and reducing the operational difficulty and quality control costs during production. The high-precision, low-tapered glass micropores prepared by this method have a depth-to-diameter ratio greater than 10 and a taper less than 0.01°. They can perfectly match the needs of multiple scenarios in CPO systems, such as optical coupling, electrical interconnection, and heat dissipation. They are also suitable for micropore preparation in other fields such as microfluidic chips and optical components, and have broad application prospects. Attached Figure Description
[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1 This is a schematic diagram of the blind hole processing of the present invention. The blue arrow indicates the direction of laser movement.
[0028] Figure 2 The images are electron microscope images of the upper and lower blind holes processed in Example 1, (a) lower blind hole; (b) upper blind hole.
[0029] Figure 3 The images are electron microscope images of the through-hole after wet etching in Example 1: (a) lower end of the through-hole; (b) upper end of the through-hole.
[0030] Figure 4 The images are electron microscope images of the through-hole after wet etching in Example 2: (a) lower end of the through-hole; (b) upper end of the through-hole.
[0031] Figure 5 The images are electron microscope images of the through-hole after wet etching in Example 3: (a) lower end of the through-hole; (b) upper end of the through-hole.
[0032] Figure 6The images are electron microscope images of the through-hole after wet etching in Example 4: (a) lower end of the through-hole; (b) upper end of the through-hole.
[0033] Figure 7 The images are electron microscope images of the through-hole after wet etching in Example 5: (a) lower end of the through-hole; (b) upper end of the through-hole.
[0034] Figure 8 The images shown are electron microscope images of the through-hole after wet etching in Example 6: (a) lower end of the through-hole; (b) upper end of the through-hole.
[0035] Figure 9 The images are electron microscope images of the through-hole after wet etching in Example 7: (a) lower end of the through-hole; (b) upper end of the through-hole. Detailed Implementation
[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0037] Example 1 A method for fabricating glass microporous structures using wet etching combined with femtosecond laser dual-pulse etching includes the following steps: (1) Glass surface treatment: Use alcohol and deionized water to ultrasonically clean the quartz glass substrate with a thickness of 200µm for 15 minutes, and dry it in an oven and cool it to 25°C.
[0038] (2) Fabrication of glass micropore structures: A dual-pulse femtosecond laser with a wavelength of 1030 nm, a repetition frequency of 25 kHz, and a pulse width of 390 fs was used. The pulse interval between the two pulses was 25 ns. The energy of the first pulse was greater than that of the second pulse, with an energy ratio of 10:8. The laser power was 0.39 W, the exposure time was 1000 µs, the scanning speed was 1.5 mm / s, and the scanning acceleration was 0.75 mm / s. 2 The movement distance is 5µm. An objective lens with a numerical aperture of 0.4 (20×) is selected. First, the CCD is focused onto the upper surface of the quartz sample. Then, by adjusting the settings, the femtosecond laser processes the glass from bottom to top, starting from the back. Figure 1 As shown, the laser focus moves from bottom to top to complete the fabrication of blind hole structures on both the top and bottom surfaces of the sample. Figure 2 The diameters are the upper and lower blind holes, with the lower blind hole measuring 33.99 µm and the upper blind hole measuring 34.62 µm.
[0039] (3) Wet etching of the glass-modified area: After the blind hole structure is fabricated, the sample is etched with 5% HF acid for 100 minutes to remove the modified area between the upper and lower blind holes, forming a through hole with excellent taper, such as Figure 3 As shown, the hole diameter is 36.22 µm, the depth-to-diameter ratio is 5.52, and the taper is 0.193°.
[0040] (4) Re-treatment of glass surface: After laser processing, ultrasonic cleaning with acetone, alcohol and deionized water for 15 minutes respectively, and then drying in an oven and cooling to 25°C.
[0041] Example 2 A method for fabricating glass microporous structures using wet etching combined with femtosecond laser dual-pulse etching includes the following steps: (1) Glass surface treatment: Use alcohol and deionized water to ultrasonically clean a quartz glass substrate with a thickness of 500µm for 15 minutes, and then dry it in an oven and cool it to 25°C.
[0042] (2) Fabrication of glass micropore structures: A dual-pulse femtosecond laser with a wavelength of 1030 nm, a repetition frequency of 25 kHz, and a pulse width of 390 fs was used. The pulse interval between the two pulses was 25 ns. The energy of the first pulse was greater than that of the second pulse, with an energy ratio of 10:8. The laser power was 0.36 W, the exposure time was 1000 µs, the scanning speed was 1.5 mm / s, and the scanning acceleration was 0.75 mm / s. 2 The moving distance is 5µm. An objective lens with a numerical aperture of 0.4 (20×) is selected. First, the CCD is focused on the surface of the quartz sample. Then, by setting the parameters, the femtosecond laser is used to process the glass from the back to the top, completing the preparation of the blind hole structure on the upper and lower surfaces of the sample.
[0043] (3) Wet etching of the glass-modified area: After the blind hole structure is fabricated, the sample is etched with 5% HF acid for 90 minutes to remove the modified area between the upper and lower blind holes, forming a through hole with excellent taper, such as Figure 4 As shown, the hole diameter is 48.43 µm, the depth-to-diameter ratio is 10.32, and the taper is 0.0028°.
[0044] (4) Re-treatment of glass surface: After laser processing, ultrasonic cleaning with acetone, alcohol and deionized water for 15 minutes respectively, and then drying in an oven and cooling to 25°C.
[0045] Example 3 A method for fabricating glass microporous structures using wet etching combined with femtosecond laser dual-pulse etching includes the following steps: (1) Glass surface treatment: Use alcohol and deionized water to ultrasonically clean a quartz glass substrate with a thickness of 200 µm for 15 minutes, and then dry it in an oven and cool it to 25°C.
[0046] (2) Fabrication of glass micropore structures: A dual-pulse femtosecond laser with a wavelength of 1030 nm, a repetition frequency of 25 kHz, and a pulse width of 390 fs was used. The pulse interval between the two pulses was 25 ns. The energy of the first pulse was greater than that of the second pulse, with an energy ratio of 10:8. The laser power was 0.30 W, the exposure time was 1000 µs, the scanning speed was 1.5 mm / s, and the scanning acceleration was 0.75 mm / s. 2 The moving distance is 5µm. An objective lens with a numerical aperture of 0.4 (20×) is selected. First, the CCD is focused on the surface of the quartz sample. Then, by setting the parameters, the femtosecond laser is used to process the glass from the back to the top, completing the preparation of the blind hole structure on the upper and lower surfaces of the sample.
[0047] (3) Wet etching of the glass-modified area: After the blind hole structure is fabricated, the sample is etched with 5% HF acid for 90 minutes to remove the modified area between the upper and lower blind holes, forming a through hole with excellent taper, such as Figure 5 As shown, the hole diameter is 32.90 µm, the depth-to-diameter ratio is 6.08, and the taper is 0.0214°.
[0048] (4) Re-treatment of glass surface: After laser processing, ultrasonic cleaning with acetone, alcohol and deionized water for 15 minutes respectively, and then drying in an oven and cooling to 25°C.
[0049] Example 4 A method for fabricating glass microporous structures using wet etching combined with femtosecond laser dual-pulse etching includes the following steps: (1) Glass surface treatment: Use alcohol and deionized water to ultrasonically clean the quartz glass substrate with a thickness of 200µm for 15 minutes, and dry it in an oven and cool it to 25°C.
[0050] (2) Fabrication of glass micropore structures: A dual-pulse femtosecond laser with a wavelength of 1030 nm, a repetition frequency of 25 kHz, and a pulse width of 390 fs was used. The pulse interval between the two pulses was 25 ns. The energy of the first pulse was greater than that of the second pulse, with an energy ratio of 10:8. The laser power was 0.39 W, the exposure time was 1000 µs, the scanning speed was 1.5 mm / s, and the scanning acceleration was 0.75 mm / s. 2 The moving distance is 5µm. An objective lens with a numerical aperture of 0.4 (20×) is selected. First, the CCD is focused on the surface of the quartz sample. Then, by setting the parameters, the femtosecond laser is used to process the glass from the back to the top, completing the preparation of the blind hole structure on the upper and lower surfaces of the sample.
[0051] (3) Wet etching of the glass-modified area: After the blind hole structure is fabricated, the sample is etched with 5% HF acid for 90 minutes to remove the modified area between the upper and lower blind holes, forming a through hole with excellent taper, such as Figure 6 As shown, the hole diameter is 36.22 µm, the depth-to-diameter ratio is 5.52, and the taper is 0.193°.
[0052] (4) Re-treatment of glass surface: After laser processing, ultrasonic cleaning with acetone, alcohol and deionized water for 15 minutes respectively, and then drying in an oven and cooling to 25°C.
[0053] Example 5 A method for fabricating glass microporous structures using wet etching combined with femtosecond laser dual-pulse etching includes the following steps: (1) Glass surface treatment: Use alcohol and deionized water to ultrasonically clean a quartz glass substrate with a thickness of 500 µm for 15 minutes, and then dry it in an oven and cool it to 25°C.
[0054] (2) Fabrication of glass micropore structures: A dual-pulse femtosecond laser with a wavelength of 1030 nm, a repetition frequency of 25 kHz, and a pulse width of 390 fs was used. The pulse interval between the two pulses was 25 ns. The energy of the first pulse was greater than that of the second pulse, with an energy ratio of 10:8. The laser power was 0.36 W, the exposure time was 1000 µs, the scanning speed was 1.5 mm / s, and the scanning acceleration was 0.75 mm / s. 2 The moving distance is 5µm. An objective lens with a numerical aperture of 0.4 (20×) is selected. First, the CCD is focused on the surface of the quartz sample. Then, by setting the parameters, the femtosecond laser is used to process the glass from the back to the top, completing the preparation of the blind hole structure on the upper and lower surfaces of the sample.
[0055] (3) Wet etching of the glass-modified area: After the blind hole structure is fabricated, the sample is etched with 5% HF acid for 90 minutes to remove the modified area between the upper and lower blind holes, forming a through hole with excellent taper, such as Figure 7 As shown, the hole diameter is 44.65 µm, the depth-to-diameter ratio is 11.19, and the taper is 0.042°.
[0056] (4) Re-treatment of glass surface: After laser processing, ultrasonic cleaning with acetone, alcohol and deionized water for 15 minutes respectively, and then drying in an oven and cooling to 25°C.
[0057] Example 6 A method for fabricating glass microporous structures using wet etching combined with femtosecond laser dual-pulse etching includes the following steps: (1) Glass surface treatment: Use alcohol and deionized water to ultrasonically clean the quartz glass substrate with a thickness of 200µm for 15 minutes, and dry it in an oven and cool it to 25°C.
[0058] (2) Fabrication of glass micropore structures: A dual-pulse femtosecond laser with a wavelength of 1030 nm, a repetition frequency of 20 kHz, and a pulse width of 390 fs was used. The pulse interval between the two pulses was 30 ns. The energy of the first pulse was greater than that of the second pulse, with an energy ratio of 10:7. The laser power was 0.35 W, the exposure time was 900 µs, the scanning speed was 1.5 mm / s, and the scanning acceleration was 0.75 mm / s. 2 The moving distance is 5µm. An objective lens with a numerical aperture of 0.4 (20×) is selected. First, the CCD is focused on the surface of the quartz sample. Then, by setting the parameters, the femtosecond laser is used to process the glass from the back to the top, completing the preparation of the blind hole structure on the upper and lower surfaces of the sample.
[0059] (3) Wet etching of the glass-modified area: After the blind hole structure is fabricated, the sample is etched with 5% HF acid for 90 minutes to remove the modified area between the upper and lower blind holes, forming a through hole with excellent taper, such as Figure 8 As shown, the hole diameter is 48.43 µm, the depth-to-diameter ratio is 10.32, and the taper is 0.0029°.
[0060] (4) Re-treatment of glass surface: After laser processing, ultrasonic cleaning with acetone, alcohol and deionized water for 15 minutes respectively, and then drying in an oven and cooling to 25°C.
[0061] Example 7 A method for fabricating glass microporous structures using wet etching combined with femtosecond laser dual-pulse etching includes the following steps: (1) Glass surface treatment: Use alcohol and deionized water to ultrasonically clean a quartz glass substrate with a thickness of 500µm for 15 minutes, and then dry it in an oven and cool it to 25°C.
[0062] (2) Fabrication of glass micropore structures: A dual-pulse femtosecond laser with a wavelength of 1030 nm, a repetition frequency of 30 kHz, and a pulse width of 410 fs was used. The pulse interval between the two pulses was 20 ns. The energy of the first pulse was greater than that of the second pulse, with an energy ratio of 10:9. The laser power was 0.39 W, the exposure time was 1100 µs, the scanning speed was 1.5 mm / s, and the scanning acceleration was 0.75 mm / s. 2 The moving distance is 5µm. An objective lens with a numerical aperture of 0.4 (20×) is selected. First, the CCD is focused on the surface of the quartz sample. Then, by setting the parameters, the femtosecond laser is used to process the glass from the back to the top, completing the preparation of the blind hole structure on the upper and lower surfaces of the sample.
[0063] (3) Wet etching of the glass-modified area: After the blind hole structure is fabricated, the sample is etched with 10% HF acid for 90 minutes to remove the modified area between the upper and lower blind holes, forming a through hole with excellent taper, such as Figure 9 As shown, the hole diameter is 43.30 µm, the depth-to-diameter ratio is 11.54, and the taper is 0.101°.
[0064] (4) Re-treatment of glass surface: After laser processing, ultrasonic cleaning with acetone, alcohol and deionized water for 15 minutes respectively, and then drying in an oven and cooling to 25°C.
[0065] 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for fabricating glass micropore structures using wet etching combined with femtosecond laser dual-pulse etching, characterized in that, Includes the following steps: (1) Suspend and fix the quartz glass, so that the double-pulse femtosecond laser passes through the quartz glass and is focused on the outer side of the back of the quartz glass; (2) Move the focus so that the dual-pulse femtosecond laser processes the quartz glass from the back up, forming two blind holes on the upper and lower surfaces of the quartz glass, and forming a modified area between the two blind holes. (3) Wet etching is performed on the quartz glass containing blind holes to etch away the modified areas in the quartz glass, and the upper and lower blind holes are connected to form a through hole.
2. The method for fabricating glass micropore structures by wet etching combined with femtosecond laser dual-pulse etching according to claim 1, characterized in that, The dual-pulse femtosecond laser has a wavelength of 1025 nm - 1035 nm, a repetition frequency of 20 kHz - 30 kHz, a pulse width of 370 fs - 410 fs, a total laser power of 0.30 W - 0.39 W, a dual-pulse interval of 20 - 30 ns, an energy ratio of 10:7 - 9, and the energy of the first pulse is greater than that of the second pulse. The exposure time is 900 µs - 1100 µs.
3. The method for fabricating glass micropore structures by wet etching combined with femtosecond laser dual-pulse etching according to claim 2, characterized in that, The objective lens has a numerical aperture of 0.4-0.8 and a magnification of 10-40 times.
4. The method for fabricating glass micropore structures by wet etching combined with femtosecond laser dual-pulse etching according to claim 3, characterized in that, In step (1), the distance between the focal point of the objective lens and the surface of the quartz glass is 10-30 μm.
5. The method for fabricating glass micropore structures by wet etching combined with femtosecond laser dual-pulse etching according to claim 4, characterized in that, The etching solution used in the wet etching process is hydrofluoric acid, and the etching time is 60-100 minutes.
6. The method for fabricating glass micropore structures by wet etching combined with femtosecond laser dual-pulse as described in claim 5, characterized in that, The concentration of the hydrofluoric acid is 5wt%-10wt%.
7. The method for fabricating a glass micropore structure by wet etching combined with femtosecond laser dual-pulse as described in claim 6, characterized in that, The thickness of the quartz glass is 200-500 μm.
8. The method for fabricating glass micropore structures by wet etching combined with femtosecond laser dual-pulse etching according to claim 7, characterized in that, The depth-to-diameter ratio of the through hole is 3-15.
9. The method for fabricating a glass micropore structure by wet etching combined with femtosecond laser dual-pulse etching according to any one of claims 1-8, characterized in that, In step (1), the quartz glass needs to be cleaned beforehand.
10. The method for fabricating a glass micropore structure by wet etching combined with femtosecond laser dual-pulse etching according to claim 9, characterized in that, In step (3), the quartz glass after wet etching needs to be cleaned.