Aluminum-based semiconductor cleaning method and system combining ultrasonic waves and chemical reagents

Abstract

The invention relates to the technical field of semiconductor cleaning, in particular to an aluminum-based semiconductor cleaning method and system combining ultrasonic waves and chemical reagents, and the system comprises a multi-band ultrasonic oscillation cleaning device, a chemical reagent distribution assembly and a dynamic stirring assembly. The frequency of the ultrasonic generator is adjusted through the intelligent controller, a reflecting plate is arranged in the cleaning tank to form turbulent flow, chemical reagents are mixed in proportion to reduce corrosivity and improve the dissolving capacity, and the dynamic stirring assembly enhances fluidity. By optimizing the ultrasonic frequency, the chemical reagent ratio and the stirring mode, the cleaning efficiency of the aluminum-based silicon carbide composite material is remarkably improved, the reagent dosage is reduced, and the purity of the cleaned material can reach 99.9% or above.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor manufacturing and cleaning, and specifically relates to a method and system for cleaning aluminum-based semiconductors by combining ultrasound and chemical reagents. Background Art

[0002] With the continuous development of semiconductor material recycling technology, the recycling process of aluminum-based silicon carbide composite materials has gradually become a research hotspot due to its important role in reducing production costs and promoting semiconductor industrialization. However, the existing aluminum-based silicon carbide composite material recycling process still has significant deficiencies in cleaning efficiency, material purity, and process complexity. These problems directly affect the quality and economic efficiency of the recycled materials. After searching, it was found that the patent with publication number CN118270789B (publication date August 9, 2024) proposed a method of combining acid dissolution with ultrasonic dispersion treatment to achieve effective separation of aluminum and silicon carbide in aluminum-based silicon carbide waste, and by multiple cleaning and vacuum drying of the solid phase silicon carbide, high-purity recycled silicon carbide powder was obtained. However, this technical solution still has many problems that need to be solved: first, the use of acid may cause corrosion to the equipment and increase maintenance costs; second, the waste liquid generated during the acid treatment process requires additional environmental protection measures, further increasing the process complexity and operating costs; in addition, the time and parameters of the ultrasonic dispersion treatment are not clearly optimized, which may lead to insufficient cleaning efficiency or excessive energy consumption. The above problems indicate that the existing aluminum-based silicon carbide composite material recycling process still has much room for improvement in terms of environmental friendliness of the cleaning method, optimization of process parameters, and overall operating cost control. Therefore, the present invention proposes a method and system for cleaning aluminum-based semiconductors that combines ultrasound and chemical reagents. The purpose is to improve cleaning efficiency and material purity by optimizing the formula of chemical reagents and ultrasonic processing parameters, while reducing the corrosiveness to equipment and the impact on the environment, thereby meeting the demand for efficient and low-cost cleaning processes in the semiconductor field. Summary of the Invention

[0003] The object of the present invention is to provide an aluminum-based semiconductor cleaning method and system combining ultrasound and chemical reagents to solve the problems raised in the above background technology.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a method for cleaning aluminum-based semiconductors combining ultrasound and chemical reagents, comprising the following steps: using a multi-band ultrasonic oscillation cleaning device to clean aluminum-based silicon carbide composite materials, the multi-band ultrasonic oscillation cleaning device comprising an ultrasonic generator, a cleaning tank, a chemical reagent distribution component and a dynamic stirring component; the ultrasonic generator comprises multiple groups of frequency-adjustable piezoelectric ceramic sheets, a signal amplifier and an intelligent controller; the inner wall of the cleaning tank is provided with a multi-layer gradient distribution reflector, and a plurality of irregularly arranged circular holes are opened on the reflector, and the diameter of the circular holes gradually changes between 1 mm and 5 mm; the chemical reagent distribution component comprises a liquid storage tank, an infusion tube and a spray head located at the end of the infusion tube, a spiral guide plate is provided inside the spray head, and the pitch of the guide plate gradually changes between 0.5 mm and 2 mm; the dynamic stirring component comprises a rotating disk located at the bottom of the cleaning tank, a stirring blade fixedly mounted on the rotating disk and a stepper motor for driving the rotating disk.

[0005] Preferably, the ultrasonic generator transmits the electrical signal to the piezoelectric ceramic piece through the signal amplifier, and the piezoelectric ceramic piece generates mechanical vibration at a preset frequency, the vibration frequency range is 20 kHz to 120 kHz, and can automatically switch between different frequency bands at a frequency of 3 Hz during the cleaning process.

[0006] Preferably, the liquid storage tank in the chemical reagent distribution assembly stores a cleaning solution composed of a mixture of nitric acid, hydrofluoric acid and corrosion inhibitor in a certain proportion, and the proportion formula is:

[0007] C 清洗液 =0.6C 硝酸 +0.3C 氢氟酸 +0.1C 缓蚀剂 Among them, C 清洗液 Indicates the total concentration of the cleaning solution in moles per liter, C 硝酸 、C 氢氟酸 、C 缓蚀剂 Represent the concentrations of nitric acid, hydrofluoric acid and corrosion inhibitor respectively, in moles per liter.

[0008] Preferably, the stirring blades in the dynamic stirring assembly include a plurality of spirally distributed arc blades, the curvature radius of the blades gradually changes between 5 cm and 15 cm, and the angle between adjacent blades is 120 degrees; the speed range of the stepping motor is 50 rpm to 300 rpm.

[0009] Preferably, the relationship between the liquid flow velocity v in the cleaning tank and the diameter d of the circular hole on the reflector is v=k·d n , where k is the proportional coefficient, ranging from 0.1 to 0.5; n is the exponential factor, ranging from 1.5 to 2.5.

[0010] Preferably, the stepper motor is controlled by a servo driver, which has a built-in PID algorithm and a control formula as follows:

[0011]

[0012] Where u(t) represents the control output, e(t) represents the deviation between the target value and the actual value, K p , K i , K d represent the proportional, integral, and differential coefficients respectively.

[0013] Preferably, the magnetic stirrer comprises a cylindrical magnetic core and a polytetrafluoroethylene coating wrapped around the outside of the magnetic core, the diameter of the magnetic core is 1 cm, the length is 3 cm, and the coating thickness is 0.5 mm; the surface of the coating is specially treated to have superhydrophobic properties.

[0014] Preferably, the liquid storage tank is externally connected to a constant pressure pump, a flow meter and a solenoid valve are provided at the infusion tube, and a pressure sensor is provided at the outlet of the spray head for real-time monitoring of the flow rate and pressure of the cleaning liquid.

[0015] Preferably, a circular groove is provided at the center of the rotating disk, and a magnetic stirring bar is installed in the groove. The magnetic stirring bar generates an eddy current effect under the action of an external magnetic field to enhance the fluidity of the cleaning liquid.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides an efficient and environmentally friendly aluminum-based semiconductor cleaning method and system through the synergistic effect of a multi-band ultrasonic oscillation cleaning device, a chemical reagent distribution component, and a dynamic stirring component. This system can not only significantly improve cleaning efficiency, but also effectively reduce the use of chemical reagents, thereby reducing cleaning costs and environmental pollution. By optimizing the ratio of the cleaning liquid, the operating parameters of the ultrasonic wave, and the operating mode of the stirring component, the present invention achieves efficient cleaning of aluminum-based silicon carbide composite materials, providing important reference value for the development of technology in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the present invention;

[0018] Figure 2 Schematic diagram of the dynamic stirring component.

[0019] In the figure: 1 ultrasonic generator, 2 rotating disk, 3 injection head, 4 liquid storage tank, 5 reflection plate, 6 cleaning tank, 7 stirring blade, 8 magnetic stirring bar. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] The present invention provides a method and system for cleaning aluminum-based semiconductors by combining ultrasound with chemical reagents, and the specific implementation methods are as follows. Figure 1 The figure shows the overall structure of the system of the present invention, which includes the core components of the multi-band ultrasonic oscillation cleaning device: an ultrasonic generator 1, a cleaning tank 6, a chemical reagent distribution component and a dynamic stirring component. These components can significantly improve the cleaning efficiency of aluminum-based silicon carbide composite materials through precise design and synergy. Among them, the ultrasonic generator is composed of multiple sets of frequency-adjustable piezoelectric ceramic plates, a signal amplifier and an intelligent controller, which are used to generate mechanical vibrations in different frequency bands to achieve efficient cleaning. The inner wall of the cleaning tank is provided with a multi-layer gradient distribution reflector 5, and a plurality of irregularly arranged circular holes are opened on the reflector 5. The diameter of the circular holes gradually changes between 1mm and 5mm to form multi-directional turbulence and enhance the cleaning effect. The chemical reagent distribution component includes a liquid storage tank 4, an infusion tube and a spray head 3. A spiral guide plate is provided inside the spray head. The pitch of the guide plate gradually changes between 0.5mm and 2mm to optimize the flow characteristics of the cleaning liquid. The dynamic stirring assembly consists of a rotating disk 2 located at the bottom of the cleaning tank, 7 stirring blades fixedly mounted on the rotating disk, and a stepper motor. The curvature radius of the stirring blades gradually changes between 5cm and 15cm, and the angle between adjacent blades is 120° to ensure uniform distribution of the cleaning liquid.

[0022] During the specific operation, the aluminum-based silicon carbide composite to be cleaned is first placed in a cleaning tank, and then an ultrasonic generator is activated. The ultrasonic generator transmits an electrical signal to a piezoelectric ceramic disc via a signal amplifier, generating mechanical vibrations at a preset frequency ranging from 20kHz to 120kHz. The disc automatically switches between different frequency bands at a rate of 3Hz during the cleaning process. For example, the ultrasonic generator can be set to alternate between 40kHz and 80kHz; 60kHz and 100kHz; or 20kHz and 120kHz. An intelligent controller adjusts the ultrasonic operating parameters in real time based on the temperature of the cleaning tank liquid and the concentration of the chemical reagent to ensure maximum cleaning efficiency. The cleaning tank liquid temperature is controlled at 40°C, 50°C, and 60°C, corresponding to chemical reagent concentrations of 0.5mol / L, 0.8mol / L, and 1.0mol / L, respectively, with cleaning times of 120s, 90s, and 60s, respectively. All three examples significantly improve cleaning efficiency and effectively reduce chemical reagent usage.

[0023] The liquid storage tank in the chemical reagent distribution assembly stores a cleaning solution composed of a mixture of nitric acid, hydrofluoric acid and corrosion inhibitor in proportion. The optimal ratio formula is: C 清洗液 =0.6C 硝酸 +0.3C 氢氟酸 +0.1C 缓蚀剂 Among them, C 清洗液 Indicates the total concentration of the cleaning solution in moles per liter, C 硝酸 、C 氢氟酸 、C 缓蚀剂 "" represents the concentrations of nitric acid, hydrofluoric acid, and corrosion inhibitor, respectively, expressed in moles per liter. This formulation achieves efficient cleaning by reducing the corrosiveness of the acidic reagent while simultaneously improving its ability to dissolve impurities on the surface of aluminum-based silicon carbide. The reservoir is connected to an external constant-pressure pump, and the infusion line is equipped with a flow meter and solenoid valve. A pressure sensor is located at the outlet of the spray head to monitor the flow rate and pressure of the cleaning fluid in real time. After exiting the spray head, the cleaning fluid is formed into a specific fluid pattern by the spiral guide vanes, further optimizing the cleaning effect.

[0024] The stepper motor in the dynamic stirring assembly drives the rotating disk to rotate, with a speed range of 50r / min to 300r / min, and can be automatically adjusted according to the viscosity of the liquid in the cleaning tank. The stirring blades include a plurality of spirally distributed arc blades, the curvature radius of the blades gradually changes between 5cm and 15cm, and the angle between adjacent blades is 120° to ensure the uniform distribution of the cleaning liquid. A circular groove is provided in the center of the rotating disk, and a magnetic stirring bar is installed in the groove. The magnetic stirring bar generates an eddy current effect under the action of an external magnetic field, further enhancing the fluidity of the cleaning liquid. The magnetic stirring bar includes a cylindrical magnetic core and a polytetrafluoroethylene coating wrapped around the outside of the magnetic core. The diameter of the magnetic core is 1cm, the length is 3cm, and the coating thickness is 0.5mm. The surface of the coating has been specially treated to give it super-hydrophobic properties, thereby reducing the adhesion and residue of the cleaning liquid. Such as Figure 2 The figure shows a partial enlarged view of the internal structure of the cleaning tank, the shape and arrangement of the rotating disk and the stirring blades, and the installation position of the magnetic stirring bar 8 in the groove.

[0025] When the liquid flow velocity in the cleaning tank reaches a critical value, the circular holes on the reflector can form a vortex effect, causing the cleaning liquid to form multi-directional turbulence in the tank. At this time, the relationship between the flow velocity v of the cleaning liquid and the diameter d of the circular hole on the reflector is v = k·d n , where k is the proportional coefficient, ranging from 0.1 to 0.5; n is the exponential factor, ranging from 1.5 to 2.5; by optimizing the circular hole diameter and distribution density, the turbulence intensity of the cleaning liquid can be significantly improved, thereby enhancing the cleaning effect. For example, the circular hole diameter is set to 2mm, the proportional coefficient k is 0.3, and the exponential factor n is 2.0; or the circular hole diameter is set to 3mm, the proportional coefficient k is 0.4, and the exponential factor n is 2.2; or the circular hole diameter is set to 4mm, the proportional coefficient k is 0.5, and the exponential factor n is 2.5. All three embodiments achieve a higher turbulence intensity, thereby significantly improving the cleaning effect.

[0026] The stepper motor is controlled by a servo driver, which has a built-in PID algorithm to accurately adjust the motor speed. The control formula of the PID algorithm is:

[0027]

[0028] Where u(t) represents the control output, e(t) represents the deviation between the target value and the actual value, K p , K i , K d Represents the proportional, integral and differential coefficients respectively. By adjusting the PID parameters, the motor speed can be accurately controlled to ensure the operation stability of the stirring blade. For example, the proportional coefficient K p Set to 1.0, the integral coefficient K iSet to 0.5, differential coefficient K d Set to 0.2, or the proportional coefficient K p Set to 1.2, the integral coefficient K i Set to 0.6, differential coefficient K d Set to 0.3, or the proportional coefficient K p Set to 1.5, the integral coefficient K i Set to 0.8, differential coefficient K d Set to 0.4. All three examples achieve precise control of the motor speed, thus ensuring the stable operation of the stirring blade.

[0029] During the cleaning process, ultrasonic vibrations combined with dynamic stirring effectively remove oxides and organic contaminants from the surface of aluminum-based silicon carbide. Ultrasonic vibrations, through high-frequency mechanical oscillations, rapidly burst bubbles in the cleaning fluid, generating a strong impact force that removes stubborn dirt from the material's surface. Dynamic stirring, through the rotational motion of the stirring blades and the eddy current effect of the magnetic stirrer, creates a uniform flow of the cleaning fluid within the tank, further enhancing the cleaning effect. After cleaning, the material purity can reach over 99.9%. Furthermore, the multi-layer gradient reflectors on the inner wall of the cleaning tank and the spiral guide vanes within the spray head work together to optimize the flow path of the cleaning fluid, avoiding blind spots and achieving a comprehensive cleaning effect.

[0030] In summary, the present invention provides an efficient and environmentally friendly aluminum-based semiconductor cleaning method and system through the synergistic effect of a multi-band ultrasonic oscillation cleaning device, a chemical reagent distribution component, and a dynamic stirring component. This system can not only significantly improve cleaning efficiency, but also effectively reduce the amount of chemical reagents used, thereby reducing cleaning costs and environmental pollution. By optimizing the ratio of the cleaning solution, the working parameters of the ultrasonic wave, and the operating mode of the stirring component, the present invention achieves efficient cleaning of aluminum-based silicon carbide composite materials, providing important reference value for the technological development of related fields.

[0031] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for cleaning aluminum-based semiconductors using a combination of ultrasound and chemical reagents, characterized by: The following steps are involved: A multi-band ultrasonic oscillation cleaning device is used to clean aluminum-based silicon carbide composite materials. The multi-band ultrasonic oscillation cleaning device includes an ultrasonic generator, a cleaning tank, a chemical reagent distribution component and a dynamic stirring component; the ultrasonic generator includes multiple groups of frequency-adjustable piezoelectric ceramic plates, a signal amplifier and an intelligent controller; the inner wall of the cleaning tank is provided with a multi-layer gradient distribution reflector, and a plurality of irregularly arranged circular holes are opened on the reflector, and the diameter of the circular holes gradually changes between 1 mm and 5 mm; the chemical reagent distribution component includes a liquid storage tank, an infusion tube and a spray head located at the end of the infusion tube, and a spiral guide plate is provided inside the spray head, and the pitch of the guide plate gradually changes between 0.5 mm and 2 mm; the dynamic stirring component includes a rotating disk located at the bottom of the cleaning tank, a stirring blade fixedly mounted on the rotating disk and a stepper motor for driving the rotating disk.

2. The method for cleaning aluminum-based semiconductors by combining ultrasound with chemical reagents according to claim 1, wherein: The ultrasonic generator transmits the electrical signal to the piezoelectric ceramic piece through the signal amplifier. The piezoelectric ceramic piece generates mechanical vibration at a preset frequency. The vibration frequency range is 20 kHz to 120 kHz, and it can automatically switch between different frequency bands at a frequency of 3 Hz during the cleaning process.

3. The method for cleaning aluminum-based semiconductors by combining ultrasound with chemical reagents according to claim 1, wherein: The liquid storage tank in the chemical reagent distribution assembly stores a cleaning solution composed of a mixture of nitric acid, hydrofluoric acid and corrosion inhibitor in a certain proportion, and the mixing ratio formula is: C 清洗液 =0.6C 硝酸 +0.3C 氢氟酸 +0.1C 缓蚀剂 ; Among them, C 清洗液 Indicates the total concentration of the cleaning solution in moles per liter, C 硝酸 、C 氢氟酸 、C 缓蚀剂 Represent the concentrations of nitric acid, hydrofluoric acid and corrosion inhibitor respectively, in moles per liter.

4. The method for cleaning aluminum-based semiconductors by combining ultrasound with chemical reagents according to claim 1, wherein: The stirring blades in the dynamic stirring assembly include multiple spirally distributed arc blades, the curvature radius of the blades gradually changes between 5 cm and 15 cm, and the angle between adjacent blades is 120 degrees; the speed range of the stepping motor is 50 rpm to 300 rpm.

5. The method for cleaning aluminum-based semiconductors by combining ultrasound with chemical reagents according to claim 1, wherein: The relationship between the liquid flow velocity v in the cleaning tank and the diameter d of the circular hole on the reflector is v=k·d n , where k is the proportional coefficient, ranging from 0.1 to 0.5; n is the exponential factor, ranging from 1.5 to 2.

5.

6. The method for cleaning aluminum-based semiconductors by combining ultrasound with chemical reagents according to claim 1, wherein: The stepper motor is controlled by a servo driver with a built-in PID algorithm. The control formula is: Where u(t) represents the control output, e(t) represents the deviation between the target value and the actual value, K p , K i , K d represent the proportional, integral, and differential coefficients respectively.

7. The method for cleaning aluminum-based semiconductors by combining ultrasound with chemical reagents according to claim 1, wherein: The magnetic stirrer includes a cylindrical magnetic core and a polytetrafluoroethylene coating wrapped around the outside of the magnetic core. The diameter of the magnetic core is 1 cm, the length is 3 cm, and the coating thickness is 0.5 mm. The surface of the coating is specially treated to have superhydrophobic properties.

8. The method for cleaning aluminum-based semiconductors by combining ultrasound with chemical reagents according to claim 1, wherein: The liquid storage tank is externally connected to a constant pressure pump, a flow meter and a solenoid valve are provided at the infusion pipe, and a pressure sensor is provided at the outlet of the spray head for real-time monitoring of the flow rate and pressure of the cleaning liquid.

9. The method for cleaning aluminum-based semiconductors by combining ultrasound with chemical reagents according to claim 1, wherein: A circular groove is provided at the center of the rotating disk, and a magnetic stirring bar is installed in the groove. The magnetic stirring bar generates an eddy current effect under the action of an external magnetic field to enhance the fluidity of the cleaning liquid.

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