Ultrasonic cleaner capable of reducing co-frequency resonance

Abstract

The invention relates to the technical field of silicon wafer cleaning, in particular to an ultrasonic cleaner capable of reducing co-frequency resonance, which comprises a cleaning box, an elastic hoisting structure is assembled between two lifting plates, a transverse connecting rod in the elastic hoisting structure is used for supporting a lifting structure, the lifting structure is used for supporting and lifting a wafer boat, and the elastic hoisting structure is used for supporting and lifting the wafer boat. Rigid bearing of a wafer boat is converted into elastic bearing, a first damping head and a second damping head are arranged in an elastic hoisting structure, the first damping head and the second damping head are made of nitrile rubber materials, and the materials can finely adjust the formant position; through three-in-one cooperation of elastic hoisting, buoyancy rigidity adjustment and frequency sweeping ultrasound, rigid connection between a wafer boat and a cleaning box is changed into an elastic link with continuously changing rigidity, so that the inherent frequency of a system dynamically drifts in the whole cleaning process, the same-frequency resonance residence time is almost eliminated, the damage risk of a silicon wafer is remarkably reduced, and the service life of the silicon wafer is prolonged. And meanwhile, the cleaning uniformity and the impurity stripping efficiency are improved through up-down slow movement of the wafer boat.

Description

Technical Field

[0001] This invention relates to the field of silicon wafer cleaning technology, and more specifically, to an ultrasonic cleaner that reduces resonance at the same frequency. Background Technology

[0002] In the field of semiconductor wet cleaning, ultrasonic cleaning has become the standard process for manufacturing silicon wafers such as silicon wafers, silicon carbide, and sapphire due to its high cavitation stripping efficiency and strong ability to remove fine particles. The typical process involves fixing a crystal boat loaded with dozens to hundreds of silicon wafers in a cleaning tank and using ultrasonic waves with a frequency of 28 kHz-130 kHz to generate cavitation in the cleaning solution to achieve the simultaneous removal of particles, metals, and organic contaminants. A search revealed that CN107068595A discloses an ultrasonic cleaning device for silicon wafers, comprising a frame with a cleaning tank, a base plate rotatably mounted on the frame and located within the cleaning tank, an ultrasonic transducer mounted on the base plate, a first driving device on the frame for driving the base plate to swing, and a frame for placing a wafer insert box within the cleaning tank. In use, the ultrasonic cleaning device for silicon wafers utilizes the first driving device to drive the base plate to swing, allowing the ultrasonic transducer to clean the silicon wafers from multiple angles. In actual use, the aforementioned patents are mostly rigidly connected by PP, PVDF or SUS to the crystal boat, silicon wafer and cleaning box, forming a high Q value elastic system. When the ultrasonic waves work at a single frequency for a long time, their driving frequency is very likely to coincide with a certain bending or torsional mode of the crystal boat and silicon wafer system, inducing resonance at the same frequency. The amplitude can be amplified within a few seconds, causing microcracks at the edge of the silicon wafer and a sharp increase in the fragmentation rate. For flexible silicon wafers, the risk of breakage increases exponentially. Existing technologies generally employ fixed grooves and pressure plates or cantilevered slots to firmly lock the crystal boat to the side wall of the cleaning tank in order to reduce relative motion. Although this simplifies the mechanical structure, it creates a rigid channel for vibration transmission. The amplitude attenuation depends on the damping of the material itself and cannot be adjusted online. The natural frequency is thus fixed, and the ultrasonic frequency can only be passively selected or the power reduced, resulting in a decrease in cleaning efficiency and affecting the cleaning effect. Based on this, the present invention discloses an ultrasonic cleaner that reduces resonance at the same frequency. Summary of the Invention

[0003] To address the issue raised in the background art, when supporting a silicon wafer-carrying boat, the use of fixed grooves and pressure plates or cantilever slots to firmly lock the boat to the side wall of the cleaning tank in order to reduce relative motion, although simplifying the mechanical structure, creates a rigid channel for vibration transmission. The amplitude attenuation depends on the damping of the material itself and cannot be adjusted online. The natural frequency is thus fixed, and the only option is to passively select the ultrasonic frequency or reduce the power, resulting in decreased cleaning efficiency and affecting the cleaning effect.

[0004] The present invention provides an ultrasonic cleaner that reduces resonance at the same frequency, including a cleaning chamber, wherein lifting structures are installed on the outer walls of both sides of the cleaning chamber, and the lifting structures are used to adjust the lifting of the lifting plate. The elastic hoisting structure is assembled between two lifting plates. The transverse connecting rod in the elastic hoisting structure is used to support the lifting structure, and the lifting structure is used to support and lift the crystal boat. A floating lifting structure is installed on the bottom side of the inner wall of the cleaning tank, and the lifting cap in the floating lifting structure acts on the bottom side of the lifting plate in the lifting structure.

[0005] During silicon wafer cleaning, a wafer boat loaded with silicon wafers is placed on a support structure. After the support structure bears the weight, the wafer boat is lifted with the help of an elastic hoisting structure, in which the hoisting springs in the elastic hoisting structure are stretched. After placement, the elastic hoisting structure and the lifted wafer boat are transported downwards by a lifting structure and immersed in the cleaning liquid in the cleaning tank. The cleaning of the silicon wafers in the wafer boat is completed under the action of an ultrasonic generator. The floating push structure provides reverse buoyancy during the liquid level rise, which gradually reduces the elongation of the hoisting springs, thereby changing the stiffness and mass distribution of the system in real time, and thus continuously shifting its natural frequency. This frequency scanning effect significantly reduces the probability of resonance between the cleaning tank and the wafer boat, which can reduce the risk of silicon wafer cracking or microcracks due to resonance.

[0006] As a further improvement to this technical solution, the elastic hoisting structure includes a connecting frame, a hoisting spring, a first connecting seat, a first damping head, a telescopic sleeve, a second connecting seat, and a transverse connecting rod. The two connecting frames are respectively fixed on the opposite surfaces of the two lifting plates. The side of each connecting frame away from the lifting plate is rotatably equipped with a first connecting seat via a connecting pin. The bottom end of the first connecting seat is fixed with a first damping head, the bottom side of the first damping head is fixed with a hoisting spring, the bottom end of the hoisting spring is fixed with a second damping head, the bottom end of the second damping head is fixed with a second connecting seat, and a transverse connecting rod is rotatably installed inside the second connecting seat. The two ends of the transverse connecting rod are respectively rotatably installed between the two second connecting seats on the same side.

[0007] As a further improvement to this technical solution, a telescopic sleeve is fixedly connected between the bottom side of the first damping head and the top sidewall of the second damping head. The telescopic sleeve is used to protect the lifting spring.

[0008] As a further improvement to this technical solution, the lifting structure includes a lifting plate, an inner damping pad, a buckle, and a longitudinal connecting rod; the lifting plate is disposed between the connecting frames and located below the connecting frames, and longitudinal connecting rods are symmetrically fixed on the sides of the lifting plate. A buckle is fixed at the end of the longitudinal connecting rod away from the lifting plate, and an inner damping pad is pasted on the inner wall of the buckle. The buckle is fastened to the transverse connecting rod, so that the inner damping pad is tightly fitted to the outer wall of the transverse connecting rod.

[0009] As a further improvement to this technical solution, the floating lifting structure includes a guide rail, a slider, a floating tube, an air inlet pipe, a lifting cap, a telescopic cover, a second spring, and a limiting ring. The guide rail is vertically fixed to the inner wall of the cleaning tank. The guide rail has a T-shaped groove, in which a slider is slidably mounted. A floating tube is fixed to one side of the slider, and telescopic covers are movably mounted at both ends of the floating tube. The floating tube communicates with the chambers of the two telescopic covers. The two ends of the floating tube are provided with constricted edges. A limiting ring is fixed to the outer surface of the end of the telescopic cover located inside the floating tube. A second spring is fixed between the limiting ring and the constricted edge of the floating tube. The second spring is sleeved on the outer side of the telescopic cover. A sealing ring is provided between the inner wall of the constricted edge of the floating tube and the outer wall of the telescopic cover. A lifting cap is fixed to the outer side of the middle part of the floating tube.

[0010] As a further improvement to this technical solution, an air inlet pipe is connected to the middle of the floating tube, and the air inlet pipe is connected to the air pump through a conduit; the air inlet pipe is a flexible air pipe, which can ensure that the floating tube maintains a reliable connection with the external air circuit during the up and down floating process.

[0011] As a further improvement to this technical solution, an ultrasonic generator is installed at the bottom of the cleaning box, and a frequency tuner is installed on the outer wall of the cleaning box. The frequency tuner is used for frequency tuning of the ultrasonic generator.

[0012] As a further improvement to this technical solution, two diversion pipes are arranged on the inner wall of the top port of the cleaning tank, and nozzles are symmetrically mounted on the diversion pipes. The two diversion pipes are connected to the water inlet pump through the cleaning pipe; a drain pipe is connected to the bottom of the cleaning tank.

[0013] As a further improvement to this technical solution, a protective cover is fixed to the outer wall of the cleaning tank. The protective cover covers the outside of the lifting structure to prevent cleaning fluid and impurities from corroding the transmission components. The lifting structure includes a guide rod, a first fixed plate, a movable lead screw, a second fixed plate, and a servo motor. The first fixed plate and the second fixed plate are installed side by side on the outer wall of the cleaning tank, with the first fixed plate located above the second fixed plate. Two guide rods are vertically fixed on the first fixed plate, and the bottom ends of the guide rods are fixed to the top side of the second fixed plate. A servo motor is installed in the middle of the top side of the second fixed plate, and a movable lead screw is installed at the output end of the servo motor. A limit hole is opened in the middle of the first fixed plate, and the movable lead screw passes vertically through the limit hole. The lifting plate is located above the first fixed plate, and threaded holes and positioning holes are opened on the lifting plate. The movable lead screw is assembled in the threaded hole through a threaded fit, and the top end of the guide rod is inserted into the positioning hole of the lifting plate.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This ultrasonic cleaner, designed to reduce resonance at the same frequency, transforms the rigid load-bearing capacity of the crystal boat into an elastic load-bearing capacity. A first and second damping head, both made of nitrile rubber, are incorporated into the elastic lifting structure. This material itself allows for fine-tuning of the resonance peak position. A lifting spring is installed between the first and second damping heads. During the cleaning process, under the action of the floating lifting structure, the air volume of the cavity increases, and the buoyancy increases accordingly. The upward thrust applied to the support plate by the lifting structure gradually increases. The stretched lifting spring gradually contracts under the action of the reverse thrust, and conversely, the length of the lifting spring gradually extends, thereby changing the system's stiffness and mass distribution in real time, and thus continuously shifting its natural frequency. This frequency scanning effect significantly reduces the probability of resonance between the cleaning chamber and the crystal boat, reducing the risk of silicon wafers cracking or developing microcracks due to resonance. By combining flexible hoisting, buoyancy stiffness adjustment, and frequency sweeping ultrasound, the rigid connection between the crystal boat and the cleaning tank is transformed into an elastic link with continuously changing stiffness. This allows the system's natural frequency to dynamically drift throughout the cleaning process, thereby almost eliminating the dwell time of resonance at the same frequency and significantly reducing the risk of silicon wafer breakage. At the same time, the slow up-and-down movement of the crystal boat improves the uniformity of cleaning and the efficiency of impurity removal. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall main structure of the present invention; Figure 2 This is a three-dimensional structural diagram of the lifting structure and the main body of the present invention; Figure 3 This is a schematic diagram of the combined structure of the elastic hoisting structure and the floating lifting structure of the present invention; Figure 4 This is a schematic diagram of the combined structure of the elastic hoisting structure and the lifting structure of the present invention; Figure 5 This is a cross-sectional schematic diagram of the elastic hoisting structure of the present invention; Figure 6 This is a schematic diagram of the lifting structure of the present invention; Figure 7 This is a schematic diagram of the floating lifting structure of the present invention; Figure 8 This is a cross-sectional schematic diagram of the floating lifting structure of the present invention; The meanings of the labels in the diagram are as follows: 1. Cleaning box; 2. Frequency tuner; 3. Cleaning pipe; 4. Diverter pipe; 5. Nozzle; 6. Drain pipe; 7. Protective cover; 8. Connecting frame; 9. Ultrasonic generator; 11. Lifting plate; 12. Guide rod; 13. First fixed plate; 14. Movable lead screw; 15. Second fixed plate; 16. Servo motor; 17. Lifting spring; 18. Connecting pin; 19. First connecting seat; 20. First damping head; 21. Telescopic sleeve; 22. Second connecting seat; 23. Lateral connecting rod; 24. Lifting plate; 25. Second damping head; 26. Inner damping pad; 27. Buckle; 28. Longitudinal connecting rod; 29. ​​Guide rail; 30. Slider; 31. Floating pipe; 32. Air inlet pipe; 33. Lifting cap; 34. Telescopic cover; 36. Second spring; 37. Limiting ring. Detailed Implementation

[0016] 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.

[0017] Therefore, such as Figure 1-8 As shown, the present invention provides an ultrasonic cleaner that reduces resonance at the same frequency, including a cleaning chamber 1, wherein lifting structures are installed on the outer walls of both sides of the cleaning chamber 1, and the lifting structures are used to adjust the lifting of the lifting plate 11. The elastic hoisting structure is assembled between the two lifting plates 11. The transverse connecting rod 23 in the elastic hoisting structure is used to support the lifting structure, and the lifting structure is used to support and lift the crystal boat. A floating lifting structure is installed on the bottom side of the inner wall of the cleaning tank 1. The lifting cap 33 in the floating lifting structure acts on the bottom side of the lifting plate 24 in the lifting structure.

[0018] During the cleaning of silicon wafers, a crystal boat carrying the silicon wafers is placed on a support structure. After the support structure bears the weight, the crystal boat carrying the silicon wafers is lifted with the help of an elastic hoisting structure, in which the hoisting spring 17 in the elastic hoisting structure is stretched. After placement, the elastic hoisting structure and the lifted crystal boat are transported downwards by a lifting structure and immersed in the cleaning liquid in the cleaning tank 1. The cleaning of the silicon wafers in the crystal boat is completed under the action of the ultrasonic generator 9. The floating push structure provides reverse buoyancy during the liquid level rise, so that the elongation of the hoisting spring 17 gradually decreases, thereby changing the stiffness and mass distribution of the system in real time, and thus continuously shifting its natural frequency. This frequency scanning effect significantly reduces the probability of resonance between the cleaning tank 1 and the crystal boat, which can reduce the risk of silicon wafer cracking or microcracks due to resonance.

[0019] In another embodiment, the elastic hoisting structure includes a connecting frame 8, a hoisting spring 17, a first connecting seat 19, a first damping head 20, a telescopic sleeve 21, a second connecting seat 22, and a transverse connecting rod 23. The two connecting frames 8 are respectively fixed on the opposite surfaces of the two lifting plates 11. The side of each connecting frame 8 away from the lifting plate 11 is rotatably equipped with a first connecting seat 19 via a connecting pin 18. The bottom end of the first connecting seat 19 is fixed with a first damping head 20. The bottom side of the first damping head 20 is fixed with a hoisting spring 17. The bottom end of the hoisting spring 17 is fixed with a second damping head 25. The bottom end of the second damping head 25 is fixed with a second connecting seat 22. A transverse connecting rod 23 is rotatably installed inside the second connecting seat 22. The two ends of the transverse connecting rod 23 are respectively rotatably installed between the two second connecting seats 22 on the same side.

[0020] When hoisting the crystal boat containing silicon wafers, both the first damping head 20 and the second damping head 25 are made of nitrile rubber, which itself can finely adjust the position of the resonance peak. A hoisting spring 17 is installed between the first damping head 20 and the second damping head 25. When the crystal boat is placed on the lifting structure, the transverse connecting rod 23 acts as a direct force-bearing component to bear the weight of the crystal boat and transmits the downward pulling force to the hoisting spring 17 through the second connecting seat 22, causing it to be stretched. During the cleaning process, under the action of the floating lifting structure, the air volume of the cavity increases, and the buoyancy increases accordingly. The upward pushing force applied to the lifting plate 24 by the lifting structure gradually increases. The stretched hoisting spring 17 gradually contracts under the action of the reverse thrust. Since the elongation of the hoisting spring 17 changes in real time, the vibration generated by the cleaning box 1 is not easily transmitted to the crystal boat through the elastic hoisting structure, thereby effectively reducing the probability of resonance between the crystal boat and the cleaning box 1 and ensuring the integrity of the silicon wafers.

[0021] In another embodiment, a telescopic sleeve 21 is fixedly connected between the bottom side of the first damping head 20 and the top sidewall of the second damping head 25. The telescopic sleeve 21 is used to protect the lifting spring 17. To prevent the lifting spring 17 from being corroded by the cleaning fluid, the upper and lower ends of the telescopic sleeve 21 are respectively connected to the first damping head 20 and the second damping head 25. The first damping head 20, the telescopic sleeve 21 and the second damping head 25 together form a protective enclosure for the lifting spring 17, preventing it from being corroded by the cleaning fluid without affecting the deformation of the lifting spring 17.

[0022] In another embodiment, the lifting structure includes a lifting plate 24, an inner damping pad 26, a buckle 27, and a longitudinal connecting rod 28. The lifting plate 24 is disposed between the connecting frames 8 and located below the connecting frames 8. The longitudinal connecting rod 28 is symmetrically fixed to the side of the lifting plate 24. A buckle 27 is fixed to the end of the longitudinal connecting rod 28 away from the lifting plate 24. The inner damping pad 26 is pasted on the inner wall of the buckle 27. The buckle 27 is fastened to the transverse connecting rod 23. The inner damping pad 26 is in close contact with the outer wall of the transverse connecting rod 23.

[0023] To achieve flexible hoisting of the crystal boat, the crystal boat carrying silicon wafers is placed on a support frame composed of a lifting plate 24 and a longitudinal connecting rod 28. The support frame is connected to the transverse connecting rod 23 by a buckle 27. The inner damping pad 26 is a carbon nanofiber rubber composite sheet, which can change the rigid transmission between the transverse connecting rod 23 and the buckle 27. By changing the transmission frequency through the inner damping pad 26, the cleaning box 1 and the crystal boat support frame are prevented from resonating at the same frequency, thus preventing the silicon wafers from being damaged due to resonance.

[0024] In another embodiment, the floating lifting structure includes a guide rail 29, a slider 30, a floating tube 31, an air inlet pipe 32, a lifting cap 33, a telescopic cover 34, a second spring 36, and a limiting ring 37. The guide rail 29 is vertically fixed on the inner wall of the cleaning tank 1. The guide rail 29 has a T-shaped groove, in which the slider 30 is slidably mounted. The floating tube 31 is fixed on one side of the slider 30. The telescopic covers 34 are movably mounted on both ends of the floating tube 31. The floating tube 31 communicates with the chambers of the two telescopic covers 34. The two ends of the floating tube 31 are provided with constricted edges. The telescopic cover 34 is fixed on the outer surface of one end inside the floating tube 31 with a limiting ring 37. The second spring 36 is fixed between the limiting ring 37 and the constricted edge of the floating tube 31. The second spring 36 is sleeved on the outside of the telescopic cover 34. A sealing ring is provided between the inner wall of the constricted edge of the floating tube 31 and the outer wall of the telescopic cover 34. The lifting cap 33 is fixed on the outer side of the middle part of the floating tube 31.

[0025] To change the tension of the lifting spring 17 in the elastic lifting structure, the adjustment of the tension is divided into two stages after the lifting spring 17 is subjected to tension: 1) An external air pump inflates the floating tube 31 through the air inlet pipe 32. The floating tube 31 and the two telescopic covers 34 are inflated synchronously, increasing the volume of the cavity. The two telescopic covers 34 extend outward, and the limiting ring 37 compresses the second spring 36 and accumulates elastic potential energy. The buoyancy generated after the combined cavity becomes larger increases. Under the guidance of the slider 30 along the guide rail 29, the floating tube 31 and the telescopic covers 34 float up as a whole. The lifting cap 33 pushes the lifting plate 24 upward, reducing the force on the lifting spring 17 and causing it to gradually contract. 2) When the cavity inflation reaches the preset value, the gas is released through the vent valve and the gas in the combined cavity is gradually released; the second spring 36 expands and rebounds, causing the two telescopic covers 34 to retract into the floating tube 31, the cavity volume decreases, the buoyancy decreases, the upward thrust obtained by the lifting plate 24 decreases accordingly, and the downward pull on the hoisting spring 17 increases, causing it to gradually stretch.

[0026] By changing the tension of the hoisting spring 17 in real time, its inherent transmission frequency continuously drifts, which can effectively reduce the probability of resonance at the same frequency. This dual-stage frequency scanning can complete continuous frequency shift within one cleaning cycle, effectively avoiding the characteristic frequencies of the crystal boat and silicon wafer. In addition, the up-and-down movement of the float causes the silicon wafer and the cleaning fluid to generate relative velocity, which can increase the boundary layer shear force and improve the removal rate of silicon wafer particles.

[0027] In another embodiment, an air inlet pipe 32 is connected to the middle of the floating pipe 31, and the air inlet pipe 32 is connected to the air pump through a conduit; the air inlet pipe 32 is a flexible air pipe, which can ensure that the floating pipe 31 maintains a reliable connection with the external air path during the up and down floating process.

[0028] In another embodiment, an ultrasonic generator 9 is installed at the bottom of the cleaning tank 1, and a frequency tuner 2 is installed on the outer wall of the cleaning tank 1. The frequency tuner 2 is used for frequency tuning of the ultrasonic generator 9. During cleaning, the ultrasonic generator 9 vibrates in the cleaning fluid to remove dust. The frequency tuner 2 can adjust the vibration frequency of the ultrasonic generator 9 in real time to achieve frequency sweep cleaning, prevent any fixed frequency of the ultrasonic from coinciding with the inherent frequency of the crystal boat and causing resonance, and effectively avoid damage to the silicon wafer.

[0029] The ultrasonic generator 9 is fastened with bottom-mounted bolts, and the radiating surface is treated with hard anodizing to improve cavitation intensity. The frequency modulator 2 performs periodic frequency sweeps in the 28-40kHz frequency band in 1Hz steps, with a sweep bandwidth of ±1kHz. This broadband sweep strategy can keep the crystal boat in a non-resonant steady state and reduce the breakage rate of silicon wafers.

[0030] In another embodiment, two diversion pipes 4 are arranged on the inner wall of the top port of the cleaning tank 1, and nozzles 5 are symmetrically mounted on the diversion pipes 4. The two diversion pipes 4 are connected to the water pump through the cleaning pipe 3; and a drain pipe 6 is connected to the bottom of the cleaning tank 1.

[0031] When cleaning silicon wafers, water is supplied to the distribution pipe 4 through the cleaning pipe 3 before cleaning, and the cleaning liquid is injected into the cleaning tank 1 through the nozzle 5. After cleaning, the waste liquid is discharged through the drain pipe 6. During the rise of the crystal boat, the nozzle 5 can be restarted to rinse the silicon wafer. At different rinsing stages, the cleaning pipe 3 can be switched to different cleaning liquids to meet the cleaning needs of silicon wafers at each stage.

[0032] In another embodiment, a protective cover 7 is fixed to the outer wall of the cleaning tank 1. The protective cover 7 covers the outside of the lifting structure and can prevent cleaning liquid and impurities from corroding the transmission components. The lifting structure includes guide rods 12, a first fixed plate 13, a movable lead screw 14, a second fixed plate 15, and a servo motor 16. The first fixed plate 13 and the second fixed plate 15 are installed side by side on the outer wall of the cleaning tank 1, with the first fixed plate 13 located above the second fixed plate 15. Two guide rods 12 are vertically fixed on the first fixed plate 13. The bottom end of 12 is fixed to the top side of the second fixed plate 15. A servo motor 16 is installed in the middle of the top side of the second fixed plate 15. A movable lead screw 14 is installed at the output end of the servo motor 16. A limit hole is opened in the middle of the first fixed plate 13. The movable lead screw 14 passes vertically through the limit hole. The lifting plate 11 is located above the first fixed plate 13. A threaded hole and a positioning hole are opened on the lifting plate 11 respectively. The movable lead screw 14 is assembled in the threaded hole through the threaded engagement. The top end of the guide rod 12 is set through the positioning hole of the lifting plate 11.

[0033] During silicon wafer cleaning, the wafer boat is first placed on the support structure. After the wafer boat is stabilized, the PLC controls two servo motors 16 to work synchronously, driving the movable lead screw 14 to rotate. Under the guidance of the guide rod 12, the lifting plate 11 descends, gradually immersing the wafer boat into the cleaning solution. After cleaning, the two servo motors 16 reverse synchronously, the movable lead screw 14 rotates in the opposite direction, and the lifting plate 11 rises, gradually lifting the wafer boat out of the cleaning solution.

[0034] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An ultrasonic cleaner that reduces resonance at the same frequency, characterized in that: Includes a cleaning tank (1), and lifting structures are installed on the outer walls of both sides of the cleaning tank (1), the lifting structures being used to adjust the lifting of the lifting plate (11); The elastic hoisting structure is assembled between two lifting plates (11). The transverse connecting rod (23) in the elastic hoisting structure is used to support the lifting structure, and the lifting structure is used to support and lift the crystal boat. A floating lifting structure is installed on the bottom side of the inner wall of the cleaning tank (1), and the lifting cap (33) in the floating lifting structure acts on the bottom side of the lifting plate (24) in the lifting structure.

2. An ultrasonic cleaner for reducing resonance at the same frequency according to claim 1, characterized in that: The elastic hoisting structure includes a connecting frame (8), a hoisting spring (17), a first connecting seat (19), a first damping head (20), a telescopic sleeve (21), a second connecting seat (22), and a transverse connecting rod (23). The two connecting frames (8) are respectively fixed on the opposite surfaces of the two lifting plates (11). The first connecting seat (19) is rotatably mounted on the side of each connecting frame (8) away from the lifting plate (11) via a connecting pin (18). The first damping head (20) is fixed at the bottom end of the first connecting seat (19). The hoisting spring (17) is fixed at the bottom side of the first damping head (20). The second damping head (25) is fixed at the bottom end of the hoisting spring (17). The second connecting seat (22) is fixed at the bottom end of the second damping head (25). The transverse connecting rod (23) is rotatably installed inside the second connecting seat (22). The two ends of the transverse connecting rod (23) are rotatably installed between the two second connecting seats (22) on the same side.

3. An ultrasonic cleaner for reducing resonance at the same frequency according to claim 2, characterized in that: A telescopic sleeve (21) is fixed between the bottom side of the first damping head (20) and the top side wall of the second damping head (25), and the telescopic sleeve (21) is used to protect the lifting spring (17).

4. An ultrasonic cleaner for reducing resonance at the same frequency according to claim 1, characterized in that: The lifting structure includes a lifting plate (24), an inner damping pad (26), a buckle (27), and a longitudinal connecting rod (28). The lifting plate (24) is arranged between the connecting frames (8) and is located below the connecting frames (8). The longitudinal connecting rod (28) is symmetrically fixed on the side of the lifting plate (24). The end of the longitudinal connecting rod (28) away from the lifting plate (24) is fixed with a buckle (27). The inner damping pad (26) is pasted on the inner wall of the buckle (27). The buckle (27) is fastened on the transverse connecting rod (23). The inner damping pad (26) is in close contact with the outer wall of the transverse connecting rod (23).

5. An ultrasonic cleaner for reducing resonance at the same frequency according to claim 1, characterized in that: The floating lifting structure includes a guide rail (29), a slider (30), a floating tube (31), an air inlet pipe (32), a lifting cap (33), a telescopic cover (34), a second spring (36), and a limiting ring (37). The guide rail (29) is vertically fixed on the inner wall of the cleaning tank (1). The guide rail (29) has a T-shaped groove, and a slider (30) is slidably mounted in the groove. A floating tube (31) is fixed on one side of the slider (30), and telescopic covers (34) are movably mounted at both ends of the floating tube (31). The chambers of the floating tube (31) and the two telescopic covers (34) are connected. The two ends of the floating tube (31) are provided with constricted edges. The telescopic cover (34) is fixed with a limit ring (37) on the outer side of one end inside the floating tube (31). A second spring (36) is fixed between the limit ring (37) and the constricted edge of the floating tube (31). The second spring (36) is sleeved on the outside of the telescopic cover (34). A sealing ring is provided between the inner wall of the constricted edge of the floating tube (31) and the outer wall of the telescopic cover (34). A lifting cap (33) is fixed on the outer side of the middle part of the floating tube (31).

6. An ultrasonic cleaner for reducing resonance at the same frequency according to claim 5, characterized in that: The middle part of the floating tube (31) is connected to the air inlet pipe (32), and the air inlet pipe (32) is connected to the air pump through a conduit.

7. An ultrasonic cleaner for reducing resonance at the same frequency according to claim 1, characterized in that: An ultrasonic generator (9) is installed at the bottom of the cleaning box (1), and a frequency tuner (2) is installed on the outer wall of the cleaning box (1). The frequency tuner (2) is used for frequency tuning of the ultrasonic generator (9).

8. An ultrasonic cleaner for reducing resonance at the same frequency according to claim 1, characterized in that: Two diversion pipes (4) are arranged on the inner wall of the top port of the cleaning tank (1). The diversion pipes (4) are symmetrically equipped with nozzles (5). The two diversion pipes (4) are connected to the water pump through the cleaning pipe (3). The bottom of the cleaning tank (1) is connected to the drain pipe (6).

9. An ultrasonic cleaner for reducing resonance at the same frequency according to claim 1, characterized in that: A protective cover (7) is fixed to the outer wall of the cleaning tank (1). The protective cover (7) is used to protect the lifting structure. The lifting structure includes a guide rod (12), a first fixed plate (13), a movable lead screw (14), a second fixed plate (15), and a servo motor (16). The first fixed plate (13) and the second fixed plate (15) are installed side by side on the outer wall of the cleaning tank (1), and the first fixed plate (13) is located above the second fixed plate (15). Two guide rods (12) are vertically fixed on the first fixed plate (13), and the bottom end of the guide rod (12) is fixed to the second fixed plate (15). On the top side, a servo motor (16) is installed in the middle of the top side of the second fixed plate (15). A movable lead screw (14) is installed at the output end of the servo motor (16). A limit hole is opened in the middle of the first fixed plate (13). The movable lead screw (14) passes vertically through the limit hole of the first fixed plate (13). The lifting plate (11) is located above the first fixed plate (13). A threaded hole and a positioning hole are opened on the lifting plate (11). The movable lead screw (14) is assembled in the threaded hole by threaded engagement. The top end of the guide rod (12) is inserted into the positioning hole of the lifting plate (11).

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