A dust control system for silicon carbide laser processing based on multi-level adsorption synergy

Abstract

A multi-stage adsorption synergistic dust control system for silicon carbide laser processing includes a suction hood, a vibrating grid module, a porous laminar flow adsorption module, a boiling water mist module, a condensation pipe, a mixing condensation module, a drying module, and a fan, arranged sequentially and connected along the airflow direction. The vibrating grid module includes an alloy grid and a vibration device. The porous laminar flow adsorption module includes an adsorption layer disposed in the airflow channel. The boiling water mist module includes an adsorption chamber and a water mist generator to form boiling water mist to capture dust in the airflow. The condensation pipe performs preliminary condensation of the airflow to capture dust. The mixing condensation module includes an inclined condensation channel that utilizes dust in the airflow as condensation nuclei to remove dust. The inner wall of the condensation channel is alternately arranged with superhydrophilic and superhydrophobic regions. This invention can achieve stepwise dust removal from the micron to the nanometer scale, with a capture efficiency of up to 99.9%, low overall energy consumption, and recyclable materials.

Description

Technical Field

[0001] This invention relates to the field of industrial pollution treatment technology, and in particular to a silicon carbide laser processing dust control system based on multi-level adsorption synergy. Background Technology

[0002] High-power laser cutting of silicon carbide ingots requires a cleanroom environment. However, due to the high hardness of SiC wafers (Mohs hardness 9.5), kilowatt-level pulsed lasers are needed. This process generates a large amount of micron-sized (1-10μm) and nano-sized (<1μm) dust, primarily SiC / SiOx mixed dust. Traditional filtration or electrostatic adsorption methods are insufficient to completely remove these ultrafine particles, compromising the cleanliness of the cleanroom. Dust adhering to the wafer surface leads to decreased yield and increases equipment maintenance frequency.

[0003] Existing dust control methods mainly rely on airflow-suction dust collection, which uses airflow circulation (tilted discharge plate + blower + suction pipe) to sweep away dust and reduce the temperature of molten slag. This method is suitable for general metal cutting scenarios. However, this technology relies solely on airflow and filters dust through filter materials. Its capture rate for particles <0.3μm drops drastically to below 85%, making it unable to handle nanoscale dust. Frequent filter replacements compromise cleanliness, and the lack of condensation cooling design means high-temperature molten slag can easily damage the equipment. Some laser cutting processes are equipped with wet dust collection or water cooling systems, such as water-guided laser cutting technology. High-pressure water jets guide the laser, and the water flow serves both cooling and debris flushing functions, reducing thermal damage. However, these systems are complex, require continuous water supply (up to 200 tons per month), and the water circulation is prone to scaling, necessitating frequent replacements. Wastewater containing SiC dust requires additional treatment, resulting in high wastewater treatment costs and environmental pollution. Wet dust collection also introduces water vapor pollution, disrupting the temperature and humidity balance of the workshop and making it difficult to integrate into a closed-loop cleanroom system.

[0004] These processing methods mainly rely on a single processing technology and lack a graded filtration mechanism. They suffer from drawbacks such as low processing efficiency, low nanoscale dust capture rate, high energy consumption, low system integration, easy secondary diffusion of dust, and secondary pollution. A more effective and reliable processing technology is needed to address dust pollution during SiC wafer dicing. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multi-level adsorption synergy-based dust control system for silicon carbide (SiC) laser processing dust generated during high-power laser processing of silicon carbide ingots. This system can quickly and efficiently remove dust and is suitable for the control of micro dust in semiconductor processing and manufacturing environments, especially for ISO Class 1-3 ultra-clean rooms.

[0006] This invention is achieved through the following technical solution: A dust control system for silicon carbide laser processing based on multi-level adsorption synergy includes a suction hood, a vibration grid module, a porous laminar flow adsorption module, a boiling water mist module, a condensation pipe, a mixing condensation module, a drying module, and a fan, which are arranged sequentially along the airflow direction and connected to form an airflow channel. The vibration grid module includes an alloy grid and a vibration device. A plurality of the alloy grids are sequentially intercepted on the airflow channel and connected to the vibration device to collect dust in the airflow under the vibration action of the vibration device. The porous laminar flow adsorption module includes an adsorption layer disposed in the airflow channel for filtering or adsorbing dust in the airflow. The boiling water mist module includes an adsorption chamber and a water mist generator. One end of the adsorption chamber is connected to the outlet of the porous laminar flow adsorption module, and the other end is connected to the condensation pipe for the passage of airflow and water collection. The water mist generator is used to make the water in the adsorption chamber boil to form boiling water mist to capture dust in the airflow. The condensation pipe is located between the boiling water mist module and the mixing condensation module, and is used to perform preliminary condensation on the airflow discharged from the boiling water mist module. The hybrid condensation module includes an inclined condensation channel, which is used to condense the airflow passing from bottom to top, and uses the dust in the airflow as a condensation nucleus to remove dust. The drying module is used to dry the emitted gas, and the fan is connected to the drying module for the flow and discharge of the airflow.

[0007] Furthermore, the inner wall of the condensation channel is provided with alternating superhydrophilic and superhydrophobic regions. The surface of the superhydrophilic region contains a metal oxide layer, and the surface of the superhydrophobic region contains a hydrophobic organic layer.

[0008] Furthermore, the superhydrophilic region and the superhydrophobic region are arranged in alternating stripes, and the area ratio of the superhydrophobic region to the superhydrophilic region is 1:(1-4); the hydrophobic organic layer is an organosilicon layer or an organofluorine layer.

[0009] Furthermore, the inner wall of the condensation channel is made of a stainless steel substrate, and the processing method of the stainless steel substrate is as follows: Nanosecond pulsed fiber laser is used to process the preset superhydrophobic region with energy density J1 to make the surface of the superhydrophobic region rough, which is conducive to subsequent surface modification. Then, it is fumigated in organosiloxane or organofluorine vapor to form the superhydrophobic region. Nanosecond pulsed fiber lasers are used to irradiate a pre-defined superhydrophilic region with an energy density J2, generating a dense metal oxide layer. This layer is then activated by ultraviolet, infrared, or green lasers to form the superhydrophilic region.

[0010] Furthermore, the nanosecond pulsed fiber laser has a wavelength of 1064 nm, a pulse width of 200 ns, a power of 25 W, and an energy density J1 of 0.8 J / cm². 2 The energy density J2 is 0.3 J / cm³. 2 .

[0011] Furthermore, the adsorption layer in the porous laminar flow adsorption module includes a first nonwoven filter layer, a glass fiber filter layer, and a second nonwoven filter layer arranged sequentially along the airflow direction.

[0012] Furthermore, the adsorption chamber includes several interconnected upper and lower curved channels. The bottom of the lower curved channel is filled with water for generating a water curtain, and the upper part of the lower curved channel is connected to the upper curved channel to form a channel that allows airflow.

[0013] Furthermore, the water mist generator includes a heating tube disposed in the adsorption chamber for heating the water therein to form boiling water mist.

[0014] Furthermore, the water in the adsorption chamber contains 0.05%-0.2% by weight of a surfactant, so that the resulting boiling water mist contains a surfactant to wet the dust. The surfactant is preferably a fluorocarbon surfactant with a surface tension of up to 15 mN / m.

[0015] Furthermore, the alloy grid has a mesh size of 5mm×5mm and a vibration frequency of 20-200Hz.

[0016] This invention addresses the low concentration and fine particle size of dust generated during SiC wafer dicing. It establishes a four-stage gradient adsorption and surface energy synergistic control mechanism by incorporating a vibrating grid module, a porous laminar flow adsorption module, a boiling water mist module, a condensation pipe, a mixing condensation module, and a drying module. Adsorption, filtration, and condensation phase transitions remove dust step-by-step, with each stage reducing the load on subsequent stages. This achieves the gradual removal of dust from the micrometer to the nanometer scale, achieving a collection efficiency of 99.9% with low overall energy consumption and recyclable materials. The boiling water mist module innovatively uses a water curtain as the dust adsorbent, and... The condensation channels in the condensation pipes and hybrid condensation modules work together to turn dust into a condenser, reducing the condensation energy barrier and transforming it from a passive to an active process. This transforms dust from the object to be removed into a carrier for removal, greatly improving the removal efficiency. The alternating superhydrophilic and superhydrophobic regions on the condensation channels induce rapid and efficient condensation of droplets, easily capturing difficult-to-handle nanoscale dust particles, further improving the dust removal effect. This solves the core contradiction between dust control and a cleanroom environment in high-quality SiC wafer processing, and promotes the upgrade of third-generation semiconductor manufacturing towards zero pollution and near-zero energy consumption. Attached Figure Description Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the principle of the present invention.

[0018] Figure 3 This is a microscope image of condensed droplets on the surface of the superhydrophilic region in an embodiment of the present invention.

[0019] Figure 4 This is a microscope image of condensed droplets on the surface of the superhydrophobic region in an embodiment of the present invention.

[0020] Reference numerals: 1-Suction hood; 2-Vibration grid module; 3-Porous laminar flow adsorption module; 4-Boiling water mist module; 5-Condensation pipe; 6-Mixed condensation module; 7-Drying module; 8-Fan; 21-Alloy grid; 31-First non-woven filter layer; 32-Glass fiber filter layer; 33-Second non-woven filter layer; 41-Upper curved channel; 42-Lower curved channel; 61-Condensation channel; 62-Inner wall. Detailed Implementation

[0021] A dust control system for silicon carbide laser processing based on multi-level adsorption synergy, such as Figure 1 , Figure 2 As shown, the system includes a suction hood 1, a vibration grid module 2, a porous laminar flow adsorption module 3, a boiling water mist module 4, a condensation pipe 5, a mixing and condensation module 6, a drying module 7, and a fan 8, which are arranged sequentially along the airflow direction and connected by pipes. These modules are connected in sequence to form an airflow channel. The suction hood 1 is located in the silicon carbide laser processing area, generally at the bottom or side of the processing table. When laser processing is started, the dust control system is activated simultaneously.

[0022] The vibrating grid module 2 includes an alloy grid 21 and a vibration device. Several alloy grids 21 are sequentially placed on the airflow channel and connected to the vibration device to collect dust particles in the airflow under the vibration action of the device. The alloy grid 21 can be woven from alloy wires with a diameter of 0.3 mm into a 5×5 mm mesh. The vibration device can use a high-frequency vibration motor, such as a 2-pole or 4-pole motor, and is equipped with a frequency converter to adjust the frequency. The vibration frequency of the alloy grid 21 is controlled between 20-200 Hz. Periodic vibration causes dust particles in the airflow to agglomerate to 50-100 μm and then fall off due to their own weight.

[0023] The porous laminar flow adsorption module 3 includes an adsorption layer disposed in the airflow channel for filtering or adsorbing dust in the airflow.

[0024] The boiling water mist module 4 includes an adsorption chamber and a water mist generator. One end of the adsorption chamber is connected to the outlet of the porous laminar flow adsorption module 3, and the other end is connected to the condensation pipe 5 for airflow passage and water collection. The water mist generator is used to boil the water in the adsorption chamber to form boiling water mist to capture dust in the airflow.

[0025] The condensation pipe 5 is located between the boiling water mist module 4 and the mixing condensation module 6, and is used to perform preliminary condensation of the airflow discharged from the boiling water mist module 4, capturing dust and dispersing the dust in droplets. The condensation pipe 5 can be designed as a curved channel, such as a Z-shaped channel, a spherical channel, or a serpentine channel. The condensation medium can be room temperature water, and the airflow can flow from bottom to top.

[0026] The hybrid condensation module 6 includes an inclined condensation channel 61, which further condenses the airflow passing from bottom to top, utilizing dust particles in the airflow as condensation nuclei to remove dust. The airflow from the condensation pipe 5 may still contain water vapor. When the airflow at a certain temperature encounters the condensation channel 61, it condenses. The dust particles in the airflow can then replace the condensation nuclei, lowering the condensation energy barrier, promoting droplet condensation, and further improving the dust removal efficiency. This phase change dust reduction effect is particularly significant for fine dust (nanoscale dust), meeting the requirements of cleanrooms.

[0027] The drying module 7 is used to dry the emitted gas, remove moisture, and achieve ultra-cleanliness. The drying module can use hot air drying.

[0028] The fan 8 is connected to the drying module 7 and is used for airflow and discharge.

[0029] The adsorption layer's function is to adsorb dust, and it can be any existing adsorption or filter material, such as activated carbon, porous silica, or molecular sieves. In one embodiment, the porous laminar flow adsorption module 3 includes a first nonwoven filter layer 31, a glass fiber filter layer 32, and a second nonwoven filter layer 33 arranged sequentially along the airflow direction. This filters dust from the airflow, further reducing dust content, and is low-cost and easy to replace. In specific applications, the thickness of the glass fiber filter layer 32 can be greater than the thickness of the first nonwoven filter layer 31 and the second nonwoven filter layer 33. The glass fiber filter layer effectively intercepts and adsorbs dust from the airflow. The first and second nonwoven filter layers 31 and 33 serve both as permeable filters and as protectors of the glass fiber filter layer 32. For the hot airflow generated by laser processing, the first and second nonwoven filter layers 31 and 33 can be made of heat-resistant polyester or aramid nonwoven fabrics, while the glass fiber filter layer 32 itself has good high-temperature resistance.

[0030] In this embodiment, the water mist generator for the boiling water mist module 4 includes a heating tube, which is disposed in the adsorption chamber and is used to heat the water therein to form boiling water mist.

[0031] The adsorption chamber includes several interconnected upper curved channels 41 and lower curved channels 42. The bottom of the lower curved channels 42 is filled with water to generate a water curtain. A heating tube is installed at the bottom of each lower curved channel 42. The upper part of the lower curved channel 42 is connected to the upper curved channel 41 to form a channel that allows airflow. After the water in the lower curved channel 42 forms a water curtain, it fills the airflow channel, capturing dust in the airflow. Part of the dust forms droplets and flows into the bottom of the lower curved channel 42, while the other part enters the condensation pipe 5 and the mixing condensation module 6 for further condensation. The condensate flows back into the lower curved channel 42.

[0032] In one embodiment, the water in the adsorption chamber contains 0.05%-0.2% by weight of a surfactant, so that the resulting boiling water mist contains the surfactant to wet the dust and more effectively capture it. The surfactant can be a fluorocarbon surfactant with a surface tension of 15 mN / m and a concentration of 0.1 wt%. Adding the surfactant reduces the dust contact angle, fully wets the dust, and allows micron or nano-sized dust particles to be dispersed in the water, resulting in high capture efficiency.

[0033] For the hybrid condensation module 6, a condensing medium, such as condensate, is provided outside the condensation channel 61, and its condensation temperature should be lower than that of the condensation pipe 5. The inner wall 62 of the condensation channel 61 is alternately provided with superhydrophilic and superhydrophobic regions. The surface of the superhydrophilic region contains a metal oxide layer, and the surface of the superhydrophobic region contains a hydrophobic organic layer. The superhydrophobic region delays liquid film spreading, forming discrete microdroplets, while the superhydrophilic region rapidly adsorbs dust as condensation nuclei. The alternation of superhydrophobic and superhydrophilic regions provides more nucleation sites, resulting in droplet condensation and automatic surface cleaning.

[0034] In one embodiment, the superhydrophilic and superhydrophobic regions are arranged in alternating stripe patterns, with an area ratio of superhydrophobic to superhydrophilic regions of 1:(1-4). The hydrophobic organic layer is an organosilicon oxide layer or an organofluorine layer.

[0035] The inner wall 62 of the condensation channel 61 can be made of stainless steel substrate. In one embodiment, 316L stainless steel is electropolished (Ra<0.05μm), the superhydrophobic region is formed by plasma-enhanced CVD deposition of fluorocarbon nanocones with a height of 1.2μm, and the superhydrophilic region is formed by anodic oxidation to construct a TiO2 nanotube array.

[0036] In one embodiment, the inner wall 62 of the condensation channel 61 is made of a stainless steel substrate and is obtained by selective microtexturing on a 316L stainless steel substrate using a nanosecond pulsed fiber laser with a wavelength of 1064nm, a pulse width of 200ns, and a power of 25W. The specific processing method is as follows: Nanosecond pulsed fiber lasers scan a predetermined superhydrophobic region at an energy density J1, inducing material remelting to form micron-sized protrusions (15-20 μm in height). This roughens the surface of the superhydrophilic region, facilitating subsequent surface modification. The region is then fumigated in organosiloxane or organofluorine vapor for a specific time (e.g., 2 hours) to form the superhydrophobic region. The energy density J1 can be 0.8 J / cm³. 2 For organosiloxanes, long-chain silanes can be selected, and for organofluorines, fluorosilicone waterproofing agents can be selected. Testing showed that the final superhydrophobic surface allows ultrapure water to form a contact angle of 152°.

[0037] Nanosecond pulsed fiber lasers irradiate a predetermined superhydrophilic region with an energy density J², generating a dense metal oxide layer. This layer is then activated by ultraviolet, infrared, or green lasers to form the superhydrophilic region. The energy density J² can be 0.3 J / cm². 2 The resulting superhydrophilic surface can reduce the water contact angle to <5°. The composition of the metal oxide layer depends on the material of the substrate. Taking stainless steel substrate as an example, the treated metal oxide layer may include oxides of Fe, Ni, and Mn.

[0038] Figure 3 and Figure 4 The images show the surfaces of the superhydrophilic and superhydrophobic regions as observed under a microscope, both at 5x magnification. A comparison reveals that the droplet diameter is larger in the superhydrophilic region and smaller in the superhydrophobic region. When airflow passes through condensation channel 61, the superhydrophilic region preferentially adsorbs dust particles as condensation nuclei, while the superhydrophobic region maintains a discrete droplet shape. Due to the 147° contact angle difference between the two regions, efficient droplet condensation can be induced.

[0039] Example Performance Verification Dust source: 200W picosecond laser processing of SiC ingots, dust concentration approximately 22mg / m³ 3 ; Flow rate: 40m 3 / min; The final processing results are shown in Table 1.

[0040] Table 1. Treatment effect of dust with different particle size ranges

[0041] As can be seen from the above, the technical solution of the present invention has a good removal effect on dust particles ranging from micron to nanometer size.

[0042] The above detailed description is a specific description of feasible embodiments of the present invention. These embodiments are not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included in the patent scope of this case.

Claims

1. A dust control system for silicon carbide laser processing based on multi-level adsorption synergy, characterized in that, It includes a suction hood, a vibration grid module, a porous laminar flow adsorption module, a boiling water mist module, a condensation pipe, a mixing condensation module, a drying module, and a fan, which are arranged sequentially and connected along the airflow direction to form an airflow channel; The vibration grid module includes an alloy grid and a vibration device. A plurality of the alloy grids are sequentially intercepted on the airflow channel and connected to the vibration device to collect dust in the airflow under the vibration action of the vibration device. The porous laminar flow adsorption module includes an adsorption layer disposed in the airflow channel for filtering or adsorbing dust in the airflow. The boiling water mist module includes an adsorption chamber and a water mist generator. One end of the adsorption chamber is connected to the outlet of the porous laminar flow adsorption module, and the other end is connected to the condensation pipe for the passage of airflow and water collection. The water mist generator is used to make the water in the adsorption chamber boil to form boiling water mist to capture dust in the airflow. The condensation pipe is located between the boiling water mist module and the mixing condensation module, and is used to perform preliminary condensation on the airflow discharged from the boiling water mist module. The hybrid condensation module includes an inclined condensation channel, which is used to condense the airflow passing from bottom to top, and uses the dust in the airflow as a condensation nucleus to remove dust. The drying module is used to dry the emitted gas, and the fan is connected to the drying module for the flow and discharge of the airflow.

2. The silicon carbide laser processing dust control system based on multi-level adsorption synergy according to claim 1, characterized in that, The inner wall of the condensation channel is provided with alternating superhydrophilic and superhydrophobic regions. The surface of the superhydrophilic region contains a metal oxide layer, and the surface of the superhydrophobic region contains a hydrophobic organic layer.

3. The silicon carbide laser processing dust control system based on multi-level adsorption synergy according to claim 2, characterized in that, The superhydrophilic and superhydrophobic regions are arranged in alternating stripes, with the area ratio of the superhydrophobic to the superhydrophilic regions being 1:(1-4); the hydrophobic organic layer is an organosilicon layer or an organofluorine layer.

4. The silicon carbide laser processing dust control system based on multi-level adsorption synergy according to claim 2, characterized in that, The inner wall of the condensation channel is made of a stainless steel substrate, and the processing method of the stainless steel substrate is as follows: Nanosecond pulsed fiber laser is used to process the preset superhydrophobic region with energy density J1, making the surface of the superhydrophobic region rough. The superhydrophobic region is then formed by fumigation in organosiloxane or organofluorine vapor. Nanosecond pulsed fiber lasers are used to irradiate a pre-defined superhydrophilic region with an energy density J2, generating a dense metal oxide layer. This layer is then activated by ultraviolet, infrared, or green lasers to form the superhydrophilic region.

5. A silicon carbide laser processing dust control system based on multi-level adsorption synergy according to claim 4, characterized in that, The nanosecond pulsed fiber laser has a wavelength of 1064 nm, a pulse width of 200 ns, a power of 25 W, and an energy density J1 of 0.8 J / cm². 2 The energy density J2 is 0.3 J / cm³. 2 .

6. The silicon carbide laser processing dust control system based on multi-level adsorption synergy according to claim 1, characterized in that, The porous laminar flow adsorption module includes an adsorption layer comprising a first nonwoven filter layer, a glass fiber filter layer, and a second nonwoven filter layer arranged sequentially along the airflow direction.

7. A dust control system for silicon carbide laser processing based on multi-level adsorption synergy according to claim 1, characterized in that, The adsorption chamber includes several interconnected upper and lower curved channels. The bottom of the lower curved channel is filled with water for generating a water curtain, and the upper part of the lower curved channel is connected to the upper curved channel to form a channel that allows airflow.

8. A dust control system for silicon carbide laser processing based on multi-level adsorption synergy according to claim 1, characterized in that, The water mist generator includes a heating tube disposed in the adsorption chamber for heating the water therein to form boiling water mist.

9. A dust control system for silicon carbide laser processing based on multi-level adsorption synergy according to claim 1, characterized in that, The water in the adsorption chamber contains 0.05%-0.2% by weight of surfactant, so that the boiling water mist contains surfactant to wet the dust.

10. A dust control system for silicon carbide laser processing based on multi-level adsorption synergy according to claim 1, characterized in that, The alloy grid has a mesh size of 5mm×5mm and a vibration frequency of 20-200Hz.

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