An aerosol jet frequency domain shaping laser plasma resonance sintering system

Abstract

This invention provides a frequency-domain shaping laser-plasma resonance sintering system using aerosol jetting. The localized strong electromagnetic field excited by LSPR can induce electron cloud rearrangement and chemical bond reconstruction at the interface of adjacent nanoparticles, forming an atomic-level interdiffusion transition layer. This invention precisely controls the laser wavelength through frequency-domain shaping technology to match the LSPR characteristic peaks of the nanoparticles, maximizing the local electromagnetic field enhancement effect. This allows for the completion of nanoparticle melting and necking formation at ultra-low laser power, overcoming the energy efficiency limitations of traditional post-processing techniques such as high-temperature furnace heating. Simultaneously, this process is completed within the femtosecond to picosecond timescale, avoiding component segregation caused by high-temperature thermal diffusion and significantly improving the bonding strength of the nanoparticle interface. Furthermore, it achieves nanoscale selective heating, completing particle melting and necking formation at ultra-low laser power, avoiding overall thermal damage.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, and particularly relates to an aerosol jet frequency domain shaping laser plasma resonance sintering system. Background Technology

[0002] Functional microdevices (such as high-frequency radio frequency antennas, micro biosensors, and flexible optoelectronic devices) are precisely manufactured at the micro- and nano-scale to achieve core functions such as electromagnetic wave modulation, biological signal conversion, and photoelectric energy transfer. Their performance is highly dependent on the fabrication precision of the micro- and nano-structures and the quality of nanoparticle connections: ① Taking a 5G packaged antenna as an example, submicron-level high-quality metal interconnects need to be integrated on a thermosensitive polymer substrate to ensure an interfacial conductivity > 10. 6 S / m; ② Taking wearable biosensor chips as an example, it is required that the metal nanoparticle electrodes (30-50 nm) and the polymer sensitive layer achieve atomic-level bonding, while avoiding post-processing temperatures exceeding 80℃.

[0003] However, traditional aerosol jet printing (AJP) technology typically uses thermal annealing (250-400℃) to make nanoparticles conductive, which has the disadvantages of strong high-temperature sintering dependence, low local energy deposition efficiency, and weak nanoparticle interfacial bonding, making it difficult to meet the printing requirements of sensitive substrates. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides an aerosol jet frequency-domain shaping laser plasma resonance sintering system. By precisely controlling the laser wavelength through frequency-domain shaping technology to match the LSPR characteristic peaks of nanoparticles, the system maximizes the excitation of the local electromagnetic field enhancement effect, induces local energy enhancement on the surface of nanoparticles, and achieves high-quality sintering interconnection with low thermal effect, thus overcoming the energy efficiency limitations of traditional post-processing techniques such as high-temperature furnace heating.

[0005] A frequency-domain shaping laser-plasma resonant sintering system for aerosol jetting includes an aerosol generation component, a laser, an OPA optical parametric amplifier, a processing objective lens, and a processing stage. The aerosol generation component is used to generate aerosol metal nanoparticle bundles with a cross-sectional area on the order of micrometers, and to spray the aerosol metal nanoparticle bundles onto the surface of the processing substrate fixed on the processing table. The OPA optical parametric amplifier is used to perform frequency domain shaping on the Gaussian laser emitted from the laser to obtain a frequency domain shaped laser beam; wherein, the wavelength of the frequency domain shaped laser beam is located within a set neighborhood of the peak wavelength corresponding to the characteristic peak formed when aerosol metal nanoparticles generate local surface plasmon resonance effect. The processing objective lens is used to focus the frequency domain shaping laser beam onto the surface of the processing substrate, and the frequency domain shaping laser beam coincides with the aerosol metal nanoparticle beam. The processing stage is used to form printed lines of a set pattern on the surface of the processing substrate by moving itself, under the combined action of a frequency domain shaping laser beam and an aerosol metal nanoparticle beam.

[0006] Furthermore, the method for forming printed lines with a predetermined pattern on the surface of the substrate under the combined action of a frequency-domain shaping laser beam and an aerosol metal nanoparticle beam is as follows: A frequency-domain shaping laser beam is used to irradiate metal nanoparticles deposited on the surface of a processing substrate, thereby exciting the metal nanoparticles to generate a local surface plasmon resonance effect, which in turn induces a strong local electric field. A strong local electric field reduces the diffusion barrier between adjacent metal nanoparticles through near-field coupling, thereby driving the surface atoms of the metal nanoparticles to migrate in a directional manner and diffuse at grain boundaries. Subsequently, metal bonds are formed between adjacent metal nanoparticles first, accompanied by neck growth. Finally, the metal nanoparticles are sintered at a temperature lower than the bulk melting point of the metal nanoparticles, forming printed lines of the set pattern.

[0007] Furthermore, the aerosol generating assembly includes a gas cylinder (6), a gas passage (7), a pressure regulating valve (8), an air inlet (9), an ultrasonic atomization module (10), an air outlet (11), a flow valve (12), and a nozzle (13). Inert gas is discharged from the gas cylinder (6) as a carrier gas flow. The carrier gas flow is transported through the gas path (7) equipped with a pressure regulating valve (8) that can adjust the gas pressure in real time. After pressure adjustment, the carrier gas flow enters the ultrasonic atomization module (10) through the air inlet (9). The ultrasonic atomization module (10) atomizes the metal ink into an aerosol, which is then discharged through the air outlet (11) and enters the nozzle (13) through the flow valve (12). The aerosol is then sprayed and deposited on the upper surface of the processing substrate (14) through the nozzle (13).

[0008] Furthermore, the metallic ink is a silver nanoparticle dispersion solution with a mass fraction of 40%.

[0009] Furthermore, the process for obtaining the printed lines of the set pattern is as follows: Step 1: Collimate and adjust the laser beam path to ensure that the laser beam field at the output port has a Gaussian intensity distribution. Step 2: Based on the material, size, and shape characteristics of the metal nanoparticles, select the corresponding OPA optical parametric amplifier and shape the wavelength; Step 3: Adjust the laser power; Step 4: Adjust the processing platform level and determine the processing position of the laser spot on the processing substrate; Step 5: Place the metallic ink into the ultrasonic atomization module, turn on the ultrasonic atomization module, and use the principle of ultrasonic vibration to fully atomize the metallic ink and form an aerosol in the atomization chamber. Step 6: Open the gas cylinder, adjust the pressure regulating valve, and introduce inert gas as a carrier gas flow. The carrier gas flow carries the aerosol in the ultrasonic atomization module into the gas path, and check whether the nozzle sprays out aerosol nanoparticle bundles. Step 7: Adjust the flow valve to ensure that the aerosol nanoparticle bundles ejected from the nozzle meet the required parameters; Step 8: Adjust the position and angle of the aerosol nozzle to ensure that the aerosol nanoparticle beam is aligned with the processing substrate and coincides with the position of the frequency domain shaping laser beam; Step 9: During the processing, the aerosol nozzle is kept fixed at all times, the aerosol nanoparticle beam coincides with the frequency domain shaping laser beam, and the processing substrate is processed by moving the processing stage; Step 10: After processing is complete, first turn off the mechanical switch of the aerosol nozzle, then turn off the gas cylinder, and finally turn off the laser.

[0010] Furthermore, adjust the pressure regulating valve to make the air pressure 0.3 MPa; adjust the flow valve to make the carrier gas flow rate 10-30 SCCM and the sheath gas flow rate 70% of the carrier gas flow rate; the nozzle distance from the processing substrate is 2-5 mm.

[0011] Furthermore, the cross-sectional area of ​​the frequency-domain shaped laser beam is larger than that of the aerosol metal nanoparticle beam.

[0012] Furthermore, the laser power of the laser is 10-50 mW.

[0013] Beneficial effects: This invention provides a frequency-domain shaping laser-plasma resonance sintering system for aerosol jetting. The localized strong electromagnetic field excited by LSPR can induce electron cloud rearrangement and chemical bond reconstruction at the interface of adjacent nanoparticles, forming an atomic-level interdiffusion transition layer. This invention precisely controls the laser wavelength through frequency-domain shaping technology to match the LSPR characteristic peaks of the nanoparticles, maximizing the excitation of the local electromagnetic field enhancement effect. While the aerosol is jetted and deposited on the substrate surface, the frequency-domain shaping laser is used for synchronous irradiation, inducing local energy enhancement on the nanoparticle surface. This allows for the completion of nanoparticle melting and necking formation at ultra-low laser power, achieving in-situ sintering of nanoparticles during the deposition process. This overcomes the energy efficiency limitations of traditional post-processing techniques such as high-temperature furnace heating. Furthermore, this process is completed within a femtosecond to picosecond timescale, avoiding component segregation caused by high-temperature thermal diffusion and significantly improving the bonding strength of the nanoparticle interface. In addition, it achieves nanoscale selective heating, completing particle melting and necking formation at ultra-low laser power, avoiding overall thermal damage. Attached Figure Description

[0014] Figure 1 A schematic diagram of the structure of an aerosol jet frequency-domain shaping laser plasma resonance sintering system provided by the present invention; Figure 2 A schematic diagram of an aerosol jet frequency domain shaping laser plasma resonance sintering system provided by the present invention; Among them, 1—laser, 2—gauss laser, 3—OPA optical parametric amplifier, 4—frequency domain shaping laser, 5—processing objective lens, 6—gas cylinder, 7—gas path, 8—pressure regulating valve, 9—air inlet path, 10—ultrasonic atomization module, 11—air outlet path, 12—flow meter, 13—nozzle, 14—processing substrate, 15—processing pattern. Detailed Implementation

[0015] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0016] Traditional post-processing techniques, such as high-temperature furnace heating, are characterized by high heating temperatures (above 200°C) and long heating times (above 30 minutes), making them unsuitable for heat-sensitive substrates (such as hydrogels and resins). The LSPR resonance effect can locally focus light energy onto particle contact points, achieving nanoscale selective heating (energy density increased by 10²-10³ times). This allows for particle melting and necking formation at ultra-low laser power, avoiding overall thermal damage. In other words, when a laser irradiates metal nanoparticles, it excites Localized Surface Plasmon Resonance (LSPR). The strong local electric field induced by LSPR reduces the diffusion barrier between adjacent particles through near-field coupling, driving directional migration of surface atoms and grain boundary diffusion. This leads to the initial formation of metallic bonds between adjacent particles, accompanied by necking growth, ultimately achieving efficient sintering of nanoparticles and the construction of a dense conductive network at temperatures far below the bulk melting point.

[0017] Based on this, in order to solve the problems faced by existing aerosol jet printing (AJP) technology in nanoparticle processing, such as strong dependence on high-temperature sintering, low local energy deposition efficiency, and weak interfacial bonding between nanoparticles, this invention provides an aerosol jet frequency domain shaping laser plasma resonance sintering system, including an aerosol generation component, a laser, an OPA optical parametric amplifier, a processing objective lens, and a processing stage. The aerosol generation component is used to generate aerosol metal nanoparticle bundles with a cross-sectional area on the order of micrometers, and to spray the aerosol metal nanoparticle bundles onto the surface of the processing substrate fixed on the processing table. The OPA optical parametric amplifier is used to perform frequency domain shaping on the Gaussian laser emitted from the laser to obtain a frequency domain shaped laser beam; wherein, the wavelength of the frequency domain shaped laser beam is located within a set neighborhood of the peak wavelength corresponding to the characteristic peak formed when aerosol metal nanoparticles generate local surface plasmon resonance effect. The processing objective lens is used to focus the frequency domain shaping laser beam onto the surface of the processing substrate, and the frequency domain shaping laser beam coincides with the aerosol metal nanoparticle beam. The processing stage is used to form printed lines of a predetermined pattern on the surface of the processing substrate through its own movement, under the combined action of a frequency-domain shaping laser beam and an aerosol metal nanoparticle beam, as follows: A frequency-domain shaping laser beam is used to irradiate metal nanoparticles deposited on the surface of a processing substrate, thereby exciting the metal nanoparticles to generate a local surface plasmon resonance effect, which in turn induces a strong local electric field. A strong local electric field reduces the diffusion barrier between adjacent metal nanoparticles through near-field coupling, thereby driving the surface atoms of the metal nanoparticles to migrate in a directional manner and diffuse at grain boundaries. Subsequently, metal bonds are formed between adjacent metal nanoparticles first, accompanied by neck growth. Finally, the metal nanoparticles are sintered at a temperature lower than the bulk melting point of the metal nanoparticles, forming printed lines of the set pattern.

[0018] Furthermore, such as Figure 1 As shown, the aerosol generating assembly includes a gas cylinder (6), a gas path (7), a pressure regulating valve (8), an air inlet (9), an ultrasonic atomization module (10), an air outlet (11), a flow valve (12), and a nozzle (13). Inert gas is discharged from the gas cylinder (6) as a carrier gas flow. The carrier gas flow is transported through the gas path (7) equipped with a pressure regulating valve (8) that can adjust the gas pressure in real time. After pressure adjustment, the carrier gas flow enters the ultrasonic atomization module (10) through the air inlet (9). The ultrasonic atomization module (10) atomizes the metal ink into an aerosol, which is then discharged through the air outlet (11) and enters the nozzle (13) through the flow valve (12). The aerosol is then sprayed and deposited on the upper surface of the processing substrate (14) through the nozzle (13).

[0019] In other words, the frequency-domain shaping laser plasma resonance sintering system for aerosol jetting provided by this invention includes a frequency-domain shaping laser section and an aerosol jetting printing section. Specifically, for the frequency-domain shaping laser section: laser 1 generates a Gaussian laser 2, which is frequency-domain shaped by an OPA optical parametric amplifier 3 to form a frequency-domain shaping laser 4, which is then focused onto the surface of the processing substrate 14 by a processing objective lens 5. For the aerosol jetting printing section: inert gas from a gas cylinder 6 is used as a carrier gas flow, transported by a gas path 7. A pressure regulating valve 8 is installed in the gas path to adjust the gas pressure in real time. After pressure adjustment, the gas flow enters the ultrasonic atomization module 10 through the inlet 9. The ultrasonic atomization module atomizes the ink into aerosol, which then exits through the outlet 11, enters the nozzle 13 via a flow valve 12, and is jetted onto the surface of the processing substrate 14. The aerosol jetting deposition point coincides with the laser focal point, allowing selective processing of patterns 15 using this composite manufacturing method.

[0020] Furthermore, this invention uses a glass sheet as the processing substrate and a 40% (by mass) silver (Ag) nanoparticle dispersion solution as the atomizing ink. The specific sintering steps are as follows: (1) The frequency domain shaping laser-assisted aerosol selective processing system used in this invention is as follows: Figure 1 As shown, the laser optical path is collimated and adjusted to regulate the laser light field at the output port, ensuring that the light field energy has a Gaussian intensity distribution. (2) Based on the nanoparticle material (Ag), size (20-50nm), and shape characteristics (spherical particles), select the corresponding OPA optical parametric amplifier and shape the wavelength to 515nm; (3) Adjust the laser power to 10-50 mW; (4) Adjust the level of the processing platform and determine the processing position of the light spot on the substrate; (5) Place the aerosol ink in the ultrasonic atomization module, turn on the ultrasonic atomization device, and use the ultrasonic vibration principle to fully atomize the ink and form an aerosol in the atomization chamber. (6) Open the gas cylinder, adjust the pressure regulating valve to make the gas pressure 0.3MPa, and introduce inert gas as carrier gas. The carrier gas carries the aerosol ink in the ultrasonic atomization module into the gas path, and check whether the nozzle sprays out aerosol. (7) Adjust the flow valve so that the carrier gas flow rate is 10-30 SCCM and the sheath gas flow rate is 70% of the carrier gas flow rate. Test the aerosol line width sprayed from the nozzle so that the line width is about 10 μm. (8) Adjust the position and angle of the aerosol nozzle so that the nozzle is 2-5 mm away from the substrate, and the carrier gas jet is aligned with the substrate and coincides with the position of the laser spot; (9) During the processing, the aerosol nozzle is kept fixed and the aerosol carrier gas jet coincides with the light spot. The sample is processed by moving the processing table. like Figure 2 The diagram illustrates the principle of the frequency-domain shaped laser LSPR in-situ sintering method. By precisely controlling the laser wavelength (within the neighborhood of the characteristic peak) through frequency-domain shaping technology, it matches the LSPR characteristic peak of Ag nanoparticles (e.g., the LSPR characteristic peak of Ag nanoparticles is in the 400-500 nm band), maximizing the excitation of the local electromagnetic field enhancement effect. Figure 2As shown, under LSPR excitation, the nanoparticles undergo the following three processes: ① Ag nanoparticles are deposited and dispersed on the substrate by aerosol spraying, with the particles connected only by van der Waals forces; ② Under the action of frequency domain shaping laser, the Ag nanoparticles generate a localized surface plasmon resonance (LSPR) effect, which locally focuses the light energy to the particle contact point, increasing the energy density by a hundredfold; ③ The Ag nanoparticles achieve melting and sintering under localized high energy. In-situ printed Ag lines have high conductivity and require no further post-processing steps, allowing them to be directly used in electronic circuit devices.

[0021] (10) After the processing is completed, first turn off the mechanical switch of the aerosol nozzle, then turn off the gas cylinder, and finally turn off the laser.

[0022] In summary, traditional post-processing techniques such as high-temperature furnace heating are characterized by high heating temperatures (above 200°C) and long heating times (above 30 minutes), making them unsuitable for heat-sensitive substrates (hydrogels, resins, etc.). This invention provides an aerosol jetting frequency-domain shaping laser-plasma resonance sintering system. Through the LSPR resonance effect, light energy can be locally focused at the particle contact point, achieving nanoscale selective heating (energy density increased by 10²-10³ times). This allows for particle melting and necking formation at ultra-low laser power, avoiding overall thermal damage. Compared to traditional aerosol jetting technology, this invention also incorporates the LSPR-enhanced light-matter interaction mechanism to regulate the electronic coupling at the material interface, breaking through the limitations of aerodynamically focused nanoparticle jet in-situ high-quality sintering technology. It boasts significant advantages such as high energy utilization efficiency, high nanoparticle interface bonding strength, and avoidance of substrate thermal damage, providing a technological foundation for the performance leap of next-generation functional microdevices.

[0023] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A frequency-domain shaping laser-plasma resonant sintering system for aerosol jetting, characterized in that, This includes an aerosol generation component, a laser, an OPA optical parametric amplifier, a processing objective lens, and a processing stage; The aerosol generation component is used to generate aerosol metal nanoparticle bundles with a cross-sectional area on the order of micrometers, and to spray the aerosol metal nanoparticle bundles onto the surface of the processing substrate fixed on the processing table. The OPA optical parametric amplifier is used to perform frequency domain shaping on the Gaussian laser emitted from the laser to obtain a frequency domain shaped laser beam; wherein, the wavelength of the frequency domain shaped laser beam is located within a set neighborhood of the peak wavelength corresponding to the characteristic peak formed when aerosol metal nanoparticles generate local surface plasmon resonance effect. The processing objective lens is used to focus the frequency domain shaping laser beam onto the surface of the processing substrate, and the frequency domain shaping laser beam coincides with the aerosol metal nanoparticle beam. The processing stage is used to form printed lines of a set pattern on the surface of the processing substrate by moving itself, under the combined action of a frequency domain shaping laser beam and an aerosol metal nanoparticle beam.

2. The frequency-domain shaping laser plasma resonance sintering system for aerosol jetting as described in claim 1, characterized in that, The method for forming printed lines with a predetermined pattern on the surface of a substrate under the combined action of a frequency-domain shaping laser beam and an aerosol metal nanoparticle beam is as follows: A frequency-domain shaping laser beam is used to irradiate metal nanoparticles deposited on the surface of a processing substrate, thereby exciting the metal nanoparticles to generate a local surface plasmon resonance effect, which in turn induces a strong local electric field. A strong local electric field reduces the diffusion barrier between adjacent metal nanoparticles through near-field coupling, thereby driving the surface atoms of the metal nanoparticles to migrate in a directional manner and diffuse at grain boundaries. Subsequently, metal bonds are formed between adjacent metal nanoparticles first, accompanied by neck growth. Finally, the metal nanoparticles are sintered at a temperature lower than the bulk melting point of the metal nanoparticles, forming printed lines of the set pattern.

3. The frequency-domain shaping laser plasma resonance sintering system for aerosol jetting as described in claim 1, characterized in that, The aerosol generating assembly includes a gas cylinder (6), a gas passage (7), a pressure regulating valve (8), an air inlet (9), an ultrasonic atomization module (10), an air outlet (11), a flow valve (12), and a nozzle (13). Inert gas is discharged from the gas cylinder (6) as a carrier gas flow. The carrier gas flow is transported through the gas path (7) equipped with a pressure regulating valve (8) that can adjust the gas pressure in real time. After pressure adjustment, the carrier gas flow enters the ultrasonic atomization module (10) through the air inlet (9). The ultrasonic atomization module (10) atomizes the metal ink into an aerosol, which is then discharged through the air outlet (11) and enters the nozzle (13) through the flow valve (12). The aerosol is then sprayed and deposited on the upper surface of the processing substrate (14) through the nozzle (13).

4. The frequency-domain shaping laser plasma resonance sintering system for aerosol jetting as described in claim 3, characterized in that, The metallic ink is a dispersion solution of silver nanoparticles with a mass fraction of 40%.

5. The frequency-domain shaping laser plasma resonance sintering system for aerosol jetting as described in claim 3, characterized in that, The process for obtaining the print lines of a given pattern is as follows: Step 1: Collimate and adjust the laser beam path to ensure that the laser beam field at the output port has a Gaussian intensity distribution. Step 2: Based on the material, size, and shape characteristics of the metal nanoparticles, select the corresponding OPA optical parametric amplifier and shape the wavelength; Step 3: Adjust the laser power; Step 4: Adjust the processing platform level and determine the processing position of the laser spot on the processing substrate; Step 5: Place the metallic ink into the ultrasonic atomization module, turn on the ultrasonic atomization module, and use the principle of ultrasonic vibration to fully atomize the metallic ink and form an aerosol in the atomization chamber. Step 6: Open the gas cylinder, adjust the pressure regulating valve, and introduce inert gas as a carrier gas flow. The carrier gas flow carries the aerosol in the ultrasonic atomization module into the gas path, and check whether the nozzle sprays out aerosol nanoparticle bundles. Step 7: Adjust the flow valve to ensure that the aerosol nanoparticle bundles ejected from the nozzle meet the required parameters; Step 8: Adjust the position and angle of the aerosol nozzle to ensure that the aerosol nanoparticle beam is aligned with the processing substrate and coincides with the position of the frequency domain shaping laser beam; Step 9: During the processing, the aerosol nozzle is kept fixed at all times, the aerosol nanoparticle beam coincides with the frequency domain shaping laser beam, and the processing substrate is processed by moving the processing stage; Step 10: After processing is complete, first turn off the mechanical switch of the aerosol nozzle, then turn off the gas cylinder, and finally turn off the laser.

6. The frequency-domain shaping laser plasma resonance sintering system for aerosol jetting as described in claim 5, characterized in that, Adjust the pressure regulating valve to make the air pressure 0.3 MPa; adjust the flow valve to make the carrier gas flow rate 10-30 SCCM and the sheath gas flow rate 70% of the carrier gas flow rate; keep the nozzle 2-5 mm away from the processing substrate.

7. The frequency-domain shaping laser plasma resonance sintering system for aerosol jetting as described in claim 1, characterized in that, The cross-sectional area of ​​the frequency-domain shaped laser beam is larger than that of the aerosol metal nanoparticle beam.

8. The frequency-domain shaping laser plasma resonance sintering system for aerosol jetting as described in claim 1, characterized in that, The laser power of the laser is 10-50 mW.

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