Megasonic cleaning tank for semiconductor cleaning

Abstract

The utility model provides a megasonic cleaning tank for semiconductor cleaning, including megasonic transducer and tank body, megasonic transducer includes vibration plate, piezoelectric ceramic plate and PCB adapter plate, vibration plate is connected in the bottom side of tank body to form the tank bottom wall of tank body, the side wall surface of vibration plate away from tank body is first wall surface, piezoelectric ceramic plate is pasted on first wall surface, PCB adapter plate has anode spring and cathode spring, PCB adapter plate has with first wall surface fixed connection's working condition, and when PCB adapter plate is in working condition, anode spring and piezoelectric ceramic plate's anode face rely on the elasticity of anode spring and resist to realize electric connection, cathode spring and piezoelectric ceramic plate's cathode face rely on the elasticity of cathode spring and resist to realize electric connection. The utility model avoids the damage of high temperature to piezoelectric crystal when soldering tin, prevents piezoelectric crystal piezoelectric depolarization, protects the polarization state of piezoelectric crystal, eliminates the attenuation of power transmission, improves transducer service life and use efficiency.

Description

Technical Field

[0001] This utility model relates to the field of mega-sonic cleaning device design technology, specifically to a mega-sonic cleaning tank for semiconductor cleaning. Background Technology

[0002] Megasonic cleaning technology (typically referring to high-frequency ultrasonic cleaning with frequencies between 0.5MHz and 5MHz) is a key process in semiconductor manufacturing, precision optics, and biomedicine. Its development stems from the limitations of traditional ultrasonic cleaning at the micro- and nano-scale. Megahertz-level acoustic energy can penetrate liquids and clean submicron particles from objects without damage. Because the frequency range is primarily close to megahertz, this cleaning method is commonly called megasonic cleaning. Objects that can be cleaned using this method are mainly semiconductor wafers, optical devices, precision mechanical parts, and other high-precision workpieces from various stages of semiconductor device manufacturing.

[0003] Megohmonic acoustic energy is typically generated by exciting a piezoelectric crystal with a radio frequency alternating voltage. The acoustic energy generated by the piezoelectric crystal is then transmitted into the cleaning fluid through an energy transmission element, which is often the wall of the container holding the cleaning fluid. The piezoelectric crystal and its associated components are called a megohmonic transducer. For example, U.S. Patent No. 5,355,048 discloses a megohmonic transducer that includes a piezoelectric crystal connected to quartz glass via several connecting layers, and that operates at a frequency of approximately 850 kHz. Similarly, U.S. Patent No. 4,804,007 also discloses a megohmonic transducer in which the energy transmission component includes quartz, corundum, boron nitride, and a stainless steel inner liner bonded to the piezoelectric crystal with epoxy resin. These transducers all use soldered wires to transmit signals to the generator. In these high-power mega-sonic cleaning transducers, due to high-frequency vibration and high power, solder joints often fall off, causing disconnections in the drive circuit, making the transducer unable to work, and resulting in low reliability during long-term operation. Specifically, existing traditional solder joints are prone to fatigue cracking under high-frequency vibration (especially in megahertz-level conditions), which leads to increased resistance and attenuation of energy transmission. During soldering, the high temperature can easily cause piezoelectric depolarization or microcracks, which will reduce the transducer efficiency and shorten its lifespan. Utility Model Content

[0004] The megaacoustic cleaning tank for semiconductor cleaning designed in this invention can at least partially solve the above problems.

[0005] The purpose of this utility model is to provide a megasonic cleaning tank for semiconductor cleaning, including a megasonic transducer and a tank body. The megasonic transducer includes a vibrating plate, a piezoelectric ceramic plate, and a PCB adapter plate. The vibrating plate is connected to the bottom side of the tank body to form the bottom wall of the tank body. The side wall of the vibrating plate away from the tank body is a first wall surface. The piezoelectric ceramic plate is attached to the first wall surface. The PCB adapter plate has an anode spring and a cathode spring. The PCB adapter plate has a working state of being fixedly connected to the first wall surface. When the PCB adapter plate is in the working state, the anode spring and the anode surface of the piezoelectric ceramic plate are electrically connected by the elastic force of the anode spring, and the cathode spring and the cathode surface of the piezoelectric ceramic plate are electrically connected by the elastic force of the cathode spring.

[0006] In some embodiments, the cathode surface of the piezoelectric ceramic plate is attached to the vibrating plate, and the cathode surface has a folded cathode surface that is folded towards the anode surface and is located on the anode surface, with the cathode spring contacting the folded cathode surface.

[0007] In some embodiments, a plurality of connecting bolts are welded to the first wall surface of the vibrating plate, and each connecting bolt is threaded with a nut. The through hole on the PCB adapter plate is fitted onto the connecting bolt so that the PCB adapter plate is fixed to the connecting bolt by the nut.

[0008] In some embodiments, the megasonic cleaning tank further includes a rigid support member located on the side of the PCB adapter board away from the piezoelectric ceramic plate and secured to the connecting bolt by the nut.

[0009] In some embodiments, the rigid support has a connecting beam and a plurality of L-shaped arms located on the side of the connecting beam near the PCB adapter board, the L-shaped arms being spaced apart along the length of the connecting beam, and the bent section of each L-shaped arm abutting against the PCB adapter board.

[0010] In some embodiments, the piezoelectric ceramic plate, PCB adapter board, and rigid support are all multiple and equal in number.

[0011] In some embodiments, the megaacoustic transducer further includes a sealed housing, which is detachably mounted on a first side of the vibrating plate to form an accommodating space together with the vibrating plate, wherein the piezoelectric ceramic plate, the PCB adapter board and the rigid support are all located within the accommodating space.

[0012] In some embodiments, a first sealing ring is provided between the mating surfaces of the sealing housing and the vibrating plate; and / or, a through hole is formed on the sealing housing, and the through hole is sealed.

[0013] In some embodiments, the accommodating space is filled with nitrogen; and / or, silicone feet are provided on the bottom surface of the sealed housing.

[0014] In some embodiments, a second sealing ring is provided between the mating surfaces of the vibrating plate and the groove.

[0015] This invention relates to a megasonic cleaning tank for semiconductor cleaning:

[0016] The aforementioned anode and cathode springs utilize their own elasticity to achieve a reliable electrical connection with the piezoelectric ceramic plate, instead of using the welding method in existing technologies. This enhances reliability under high-power drive, avoids damage to the piezoelectric crystal (i.e., piezoelectric ceramic plate) caused by high temperatures during soldering (such as microcracks or even fatigue cracking), prevents piezoelectric depolarization of the piezoelectric crystal, protects the polarization state of the piezoelectric crystal, eliminates power transmission attenuation, and improves the transducer's service life and efficiency. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural schematic diagram of a megasonic cleaning tank for semiconductor cleaning according to an embodiment of the present invention;

[0018] Figure 2 yes Figure 1 A three-dimensional structural diagram of the megaacoustic transducer in the image;

[0019] Figure 3 yes Figure 2 An exploded view of the structure of the megaacoustic transducer in the image (silicone feet not shown);

[0020] Figure 4 yes Figure 3 An exploded view of the megasonic transducer in China, omitting the sealed housing (from another angle).

[0021] In the picture:

[0022] 1. Megasonic transducer; 11. Vibrating plate; 12. Piezoelectric ceramic plate; 120. Folded cathode surface; 13. PCB adapter board; 131. Anode spring; 132. Cathode spring; 14. Rigid support; 141. Connecting beam; 142. L-shaped support arm; 15. Sealing shell; 151. Through hole; 16. First sealing ring; 17. Silicone foot; 2. Tank; 21. Second sealing ring; 31. Connecting bolt; 32. Nut. Detailed Implementation

[0023] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. In the drawings, for clarity, the thickness of regions and layers is exaggerated. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed descriptions will be omitted.

[0024] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of the present invention. However, those skilled in the art will recognize that the technical solutions of the present invention can be practiced without one or more of the specific details described, or other methods, components, materials, etc., can be employed. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring various aspects of the present invention.

[0025] The following example describes a megasonic cleaning tank for semiconductor cleaning according to the present invention. This example is only a part of the embodiments of the present invention, but the protection scope of the present invention is not limited thereto. All other embodiments obtained by those skilled in the art without inventive effort should be covered within the protection scope of the present invention.

[0026] Please refer to the reference. Figures 1 to 4 According to an embodiment of this utility model, a megasonic cleaning tank for semiconductor cleaning is provided, including a megasonic transducer 1 and a tank body 2. The tank body 2 serves as a structure for accommodating semiconductors or similar objects to be cleaned. The megasonic transducer 1 is used to generate megasonic waves to clean the semiconductors or similar objects within the tank body 2. The megasonic transducer 1 includes a vibrating plate 11, a piezoelectric ceramic plate 12, and a PCB adapter board 13. The vibrating plate 11 is connected to the bottom side of the tank body 2 to form the bottom wall of the tank body 2. The side wall of the vibrating plate 11 closest to the tank body 2 contacts the cleaning area and transmits megasonic wave energy. The side wall of the vibrating plate 11 furthest from the tank body 2 is the first wall (i.e., the...). Figure 2(The bottom surface of the vibrating plate 11 within the range shown), the piezoelectric ceramic plate 12 is attached to the first wall surface to efficiently conduct the mega-sound waves it generates into the tank 2. The PCB adapter plate 13 has an anode spring 131 and a cathode spring 132. The aforementioned anode spring 131 and cathode spring 132 can both be made of beryllium copper. It is understood that the aforementioned PCB adapter plate 13 is electrically connected to the transducer control component shown in the figure. The PCB adapter plate 13 has a working state that is fixedly connected to the first wall surface (that is, the usage state after assembly). When the PCB adapter plate 13 is in the working state, the anode spring 131 and the anode surface of the piezoelectric ceramic plate 12 are electrically connected by the elastic contact of the anode spring 131, and the cathode spring 132 and the cathode surface of the piezoelectric ceramic plate 12 are electrically connected by the elastic contact of the cathode spring 132.

[0027] In this technical solution, the aforementioned anode spring 131 and cathode spring 132 achieve a reliable electrical connection with the piezoelectric ceramic plate 12 by utilizing their own elasticity, instead of using the welding method in the prior art. This enhances the reliability under high-power drive, avoids damage to the piezoelectric crystal (i.e., piezoelectric ceramic plate 12) caused by high temperature during soldering (such as microcracks or even fatigue cracking), prevents piezoelectric depolarization of the piezoelectric crystal, protects the polarization state of the piezoelectric crystal, eliminates the attenuation of power transmission, and improves the service life and efficiency of the transducer.

[0028] The aforementioned vibrating plate 11 can be made of stainless steel, quartz, or sapphire, and the specific material can be selected according to actual process requirements.

[0029] In some embodiments, the cathode surface of the piezoelectric ceramic plate 12 is attached to the vibrating plate 11, and the cathode surface has a folded cathode surface 120 that is folded towards the anode surface and is located on the anode surface, and the cathode spring 132 abuts against the folded cathode surface 120.

[0030] See details Figure 4 As shown, in this technical solution, the cathode surface is folded onto the anode surface of the piezoelectric ceramic plate 12 to form a planar cathode surface 120, which facilitates the convenient contact connection between the cathode spring 132 and the cathode surface of the piezoelectric ceramic plate 12.

[0031] See details Figure 4 As shown, the piezoelectric ceramic plate 12 is a rectangular ceramic sheet, and the aforementioned folded cathode surface 120 is formed by folding up one corner of the rectangle.

[0032] In some embodiments, a plurality of connecting bolts 31 are welded to the first wall surface of the vibrating plate 11, and each connecting bolt 31 is threadedly connected to a nut 32. The through hole on the PCB adapter plate 13 is fitted onto the connecting bolt 31 so that the PCB adapter plate 13 is fixed to the connecting bolt 31 by the nut 32. The aforementioned connecting bolts 31 can be welded to the vibrating plate 11, for example, using a stud-making process.

[0033] In this technical solution, the aforementioned connecting bolt 31 and nut 32 together form a detachable connection to the PCB adapter board 13. On the other hand, the turning torque of nut 32 is used to apply force (pre-tightening force) to the aforementioned anode spring 131 and cathode spring 132 to ensure reliable contact connection between the spring and the piezoelectric ceramic plate 12.

[0034] In some embodiments, the megasonic cleaning tank further includes a rigid support 14 located on the side of the PCB adapter board 13 away from the piezoelectric ceramic plate 12 and secured to the connecting bolt 31 by the nut 32. It is understood that the rigid support 14 should have sufficient rigidity to resist deformation of the PCB adapter board 13 caused by the force applied by the nut 32.

[0035] In this technical solution, by providing the aforementioned rigid support member 14 on the side of the PCB adapter board 13 away from the piezoelectric ceramic plate 12, the PCB adapter board 13 can be supported, thus preventing the PCB adapter board 13 from deforming due to the pre-tightening force applied by the screw nut 32.

[0036] In some embodiments, the rigid support 14 has a connecting beam 141 and a plurality of L-shaped arms 142 located on the side of the connecting beam 141 near the PCB adapter plate 13. Each of the L-shaped arms 142 is spaced apart along the length of the connecting beam 141, and the bent section of each L-shaped arm 142 abuts against the PCB adapter plate 13.

[0037] In this technical solution, the bent sections of the L-shaped support arms 142 arranged at intervals abut against the PCB adapter board 13, which can significantly reduce the contact area between them and the PCB adapter board 13 and reduce the probability of conductivity.

[0038] In some embodiments, there are multiple piezoelectric ceramic plates 12, PCB adapter plates 13 and rigid support members 14, and the number of each is equal. This can reduce the overall size of the piezoelectric ceramic plates 12, reduce the purchase cost and processing difficulty.

[0039] In some embodiments, the megasonic transducer 1 further includes a sealing housing 15, which is detachably mounted on the first side of the vibrating plate 11 to form an accommodating space together with the vibrating plate 11. The piezoelectric ceramic plate 12, the PCB adapter board 13, and the rigid support member 14 are all located within the accommodating space. The aforementioned sealing housing 15 can be made of materials such as stainless steel, PP, or PVDF. Furthermore, a first sealing ring 16 is provided between the mating surfaces of the sealing housing 15 and the vibrating plate 11 to improve the sealing performance.

[0040] In this technical solution, a sealed outer shell 15 is used to form a sealed cover for each related component, which can achieve the purpose of dustproofing and waterproofing each functional component.

[0041] In some embodiments, a through hole 151 is formed on the sealed housing 15, and the through hole 151 is sealed. The through hole 151 can be used, for example, to carry radio frequency cables (one end of which is electrically connected to the aforementioned PCB adapter board 13, and the other end of which is electrically connected to the transducer control component).

[0042] In some embodiments, the accommodating space is filled with nitrogen gas, which is introduced into and led out of the accommodating space through a corresponding gas pipe. The gas pipe also passes through the aforementioned through hole 151, which can be used to cool and dissipate heat from the piezoelectric ceramic plate 12, and at the same time prevent the piezoelectric ceramic plate 12 from oxidizing during operation.

[0043] The bottom surface of the sealed outer shell 15 is provided with silicone feet 17. For example, four silicone feet 17 can be evenly arranged to support and buffer the entire cleaning tank.

[0044] In some embodiments, a second sealing ring 21 is provided between the mating surfaces of the vibrating plate 11 and the tank 2 to prevent leakage of the cleaning medium.

[0045] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0046] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A megasonic cleaning tank for semiconductor cleaning, characterized in that, The device includes a megaacoustic transducer (1) and a tank (2). The megaacoustic transducer (1) includes a vibrating plate (11), a piezoelectric ceramic plate (12), and a PCB adapter plate (13). The vibrating plate (11) is connected to the bottom side of the tank (2) to form the bottom wall of the tank (2). The side wall of the vibrating plate (11) away from the tank (2) is a first wall. The piezoelectric ceramic plate (12) is attached to the first wall. The PCB adapter plate (13) has an anode spring (131). With the cathode spring (132), the PCB adapter board (13) has a working state of being fixedly connected to the first wall surface. When the PCB adapter board (13) is in the working state, the anode spring (131) and the anode surface of the piezoelectric ceramic plate (12) are electrically connected by the elastic contact of the anode spring (131), and the cathode spring (132) and the cathode surface of the piezoelectric ceramic plate (12) are electrically connected by the elastic contact of the cathode spring (132).

2. The mega-sonic cleaning tank according to claim 1, characterized in that, The cathode surface of the piezoelectric ceramic plate (12) is attached to the vibrating plate (11), and the cathode surface has a folded cathode surface (120) that is folded towards the anode surface and is located on the anode surface. The cathode spring (132) abuts against the folded cathode surface (120).

3. The mega-sonic cleaning tank according to claim 1, characterized in that, Multiple connecting bolts (31) are welded to the first wall surface of the vibrating plate (11), and each connecting bolt (31) is threaded with a nut (32). The through hole on the PCB adapter plate (13) is fitted onto the connecting bolt (31) so that the PCB adapter plate (13) is fixed to the connecting bolt (31) by the nut (32).

4. The mega-sonic cleaning tank according to claim 3, characterized in that, It also includes a rigid support (14), which is located on the side of the PCB adapter board (13) away from the piezoelectric ceramic plate (12) and is fixed to the connecting bolt (31) by the nut (32).

5. The mega-sonic cleaning tank according to claim 4, characterized in that, The rigid support (14) has a connecting beam (141) and a plurality of L-shaped arms (142) on the side of the connecting beam (141) near the PCB adapter plate (13). Each L-shaped arm (142) is spaced apart along the length of the connecting beam (141), and the bent section of each L-shaped arm (142) abuts against the PCB adapter plate (13).

6. The mega-sonic cleaning tank according to claim 4, characterized in that, The piezoelectric ceramic plate (12), PCB adapter board (13) and rigid support (14) are all multiple and of equal quantity.

7. The mega-sonic cleaning tank according to claim 4, characterized in that, The megaacoustic transducer (1) also includes a sealed housing (15), which is detachably covered on the first side of the vibrating plate (11) to form an accommodating space together with the vibrating plate (11). The piezoelectric ceramic plate (12), PCB adapter board (13) and rigid support (14) are all located within the accommodating space.

8. The mega-sonic cleaning tank according to claim 7, characterized in that, A first sealing ring (16) is provided between the mating surfaces of the sealing housing (15) and the vibrating plate (11); and / or, a through hole (151) is formed on the sealing housing (15), and the through hole (151) is sealed.

9. The mega-sonic cleaning tank according to claim 8, characterized in that, The accommodating space is filled with nitrogen; and / or, the bottom surface of the sealed housing (15) is provided with silicone feet (17).

10. The mega-sonic cleaning tank according to claim 1, characterized in that, A second sealing ring (21) is provided between the mating surfaces of the vibrating plate (11) and the groove (2).

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