Conformable megasonics launch head for semiconductor cleaning

Abstract

The utility model provides a kind of for semiconductor cleaning's attached megasonic emission head, including shell, shell has accommodating cavity, the opening side of accommodating cavity is assembled with the resonant plate that can block opening, the inside of resonant plate is attached with piezoelectric ceramic piece, PCB adapter plate is further equipped in accommodating cavity, anode spring needle and cathode spring needle are equipped on PCB adapter plate, the anode terminal of cable is fixed on PCB adapter plate and is electrically connected with anode spring needle, the cathode terminal of cable is fixed on PCB adapter plate and is electrically connected with cathode spring needle, anode spring needle and the anode face of piezoelectric ceramic piece are in contact, cathode spring needle and the cathode face of piezoelectric ceramic piece are in contact.The utility model can prevent the electrical connection failure phenomenon caused by solder fatigue fracture or conductive glue aging peeling, improve the use reliability and service life of emission nozzle.

Description

Technical Field

[0001] This utility model relates to the field of megasonic cleaning device design technology, specifically to a bonding megasonic emitting head for semiconductor cleaning. Background Technology

[0002] As process nodes advance to below 28nm (e.g., 7nm / 5nm), nanoparticles smaller than 0.1μm on wafer surfaces (such as CMP polishing residues and etching byproducts) are difficult to remove using traditional ultrasonic cleaning (due to large low-frequency cavitation bubbles) and RCA chemical cleaning due to their strong van der Waals adsorption. Megasonic cleaning generates micron-sized cavitation bubbles (1–10μm in diameter) at high frequencies. Upon rupture, these bubbles release high-density microjets that directly ablate nanoparticles. The surface standing wave effect drives the particles to detach from the surface, stably removing contaminants ≥0.2μm. The lower energy of cavitation bubble rupture and the gentler impact of the generated microjets significantly reduce the risk of physical damage to fragile device structures and precision surfaces, improving yield. Megasonic cleaning enhances cleaning efficiency through high-frequency physical forces while reducing reliance on strong chemical reagents and mechanical impact, making it one of the best options for cleaning submicron contaminants.

[0003] Existing megasonic cleaning technologies are mainly divided into three categories: tank-type, spray-type, and bonding-type. Among them, tank-type and spray-type megasonic cleaning methods suffer from disadvantages such as low sound field uniformity, high consumption of cleaning materials, and susceptibility to cross-contamination due to the relatively large distance between the cleaning nozzle and the object being cleaned. These disadvantages are significant in high-end semiconductor production lines below 28nm and in increasingly advanced semiconductor cleaning processes going forward.

[0004] Before the maturation of bonded megasonic cleaning technology, the semiconductor industry mainly relied on two types of technologies: tank-type megasonic cleaning and spray-type megasonic cleaning. The structure of tank-type megasonic cleaning is as follows: an array of piezoelectric ceramic transducers is installed at the bottom or side wall of a cuboid cleaning tank. The cleaning tank contains cleaning fluid (such as deionized water + chemical additives), and the object to be cleaned (such as a wafer) is immersed in the tank to receive megasonic energy from outside the tank for cleaning. The structure of spray-type megasonic cleaning is as follows: the cleaning nozzle has a high-pressure pump system to maintain a stable water flow, the piezoelectric transducer is embedded in the nozzle, and the water flows through the high-frequency vibrating piezoelectric ceramic sheet, carrying acoustic energy and being ejected to achieve scanning cleaning of the wafer surface.

[0005] The connection between the piezoelectric ceramic electrode surface and the coaxial cable of the existing adhesive nozzle is usually achieved by welding or bonding with conductive adhesive. However, these connection methods are prone to breakage or poor contact under long-term high-frequency vibration, temperature changes or mechanical stress, resulting in circuit breakage. This causes the adhesive megasonic transmitter to malfunction, which in turn causes the cleaning system to fail to work properly. Utility Model Content

[0006] The bonding megasonic wave transmitter designed in this invention for semiconductor cleaning can at least partially solve the above problems.

[0007] The purpose of this utility model is to provide a bonding-type megasonic wave transmitter for semiconductor cleaning, including a housing, the housing having a receiving cavity, a resonant plate capable of sealing the opening of the receiving cavity being assembled on one side of the opening, a piezoelectric ceramic sheet being bonded to the inner side of the resonant plate, and a PCB adapter board being provided inside the receiving cavity, the PCB adapter board having an anode spring pin and a cathode spring pin, the positive terminal of a cable being fixed to the PCB adapter board and electrically connected to the anode spring pin, the negative terminal of the cable being fixed to the PCB adapter board and electrically connected to the cathode spring pin, the anode spring pin abutting against the anode surface of the piezoelectric ceramic sheet, and the cathode spring pin abutting against the cathode surface of the piezoelectric ceramic sheet.

[0008] In some embodiments, the cathode surface of the piezoelectric ceramic sheet is attached to the inner wall surface of the resonant plate, the anode surface of the piezoelectric ceramic sheet is its end surface away from the resonant plate, the cathode surface has a folded area that is folded towards the anode surface and formed on the anode surface, and the free end of the cathode spring pin abuts against the folded area.

[0009] In some embodiments, the piezoelectric ceramic sheet is bonded to the resonant plate using an adhesive layer, the thickness of which is 5 micrometers to 150 micrometers.

[0010] In some embodiments, the housing includes a frame and a cover plate, the resonant plate and the cover plate are respectively connected to opposite end faces of the frame, and the PCB adapter board is connected to the inner wall surface of the cover plate.

[0011] In some embodiments, the cover plate is connected to an air inlet connector and an air outlet connector, both of which are in communication with the accommodating space.

[0012] In some embodiments, a sealing gasket is sandwiched between the mating surfaces of the frame and the cover plate.

[0013] In some embodiments, the outer end face of the cover plate is provided with mounting screw holes for connection with external support components.

[0014] In some embodiments, the cover plate is detachably connected to the frame by a plurality of screws.

[0015] In some embodiments, the outer peripheral edge of the resonant plate is formed with a flange facing the frame side, and the resonant plate is embedded and bonded to the frame via the flange.

[0016] In some embodiments, when the fitted megasonic transmitter is in use, its projection onto the plane of the wafer is fan-shaped.

[0017] This invention relates to a bonding-type megasonic wave transmitter head for semiconductor cleaning:

[0018] The aforementioned anode spring pin and cathode spring pin achieve an elastic electrical connection between the PCB adapter board and the piezoelectric ceramic sheet. This also achieves a mechanical connection between the cathode and anode of the PCB adapter board and the cathode and anode surfaces of the piezoelectric ceramic sheet, eliminating the need for traditional welding or conductive adhesive connections. This prevents electrical connection failures caused by solder joint fatigue or conductive adhesive aging and detachment, thereby improving the reliability and service life of the emission nozzle. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural schematic diagram (partial cross-section) of a bonding megasonic wave transmitter head for semiconductor cleaning according to an embodiment of the present invention;

[0020] Figure 2 yes Figure 1 A side view of a bonding megasonic transmitter head used for semiconductor cleaning;

[0021] Figure 3 yes Figure 1 A structurally exploded diagram of a bonded megasonic transmitter head used for semiconductor cleaning.

[0022] Figure 4 yes Figure 3 A schematic diagram showing the piezoelectric ceramic sheet in contact with the anode spring pin and the cathode spring pin.

[0023] Figure 5 This is a schematic diagram of the bonding megasonic wave transmitter head for semiconductor cleaning of this utility model in use.

[0024] In the picture:

[0025] 11. Frame; 12. Cover plate; 121. Mounting screw hole; 122. Screw; 2. Resonant plate; 3. Piezoelectric ceramic sheet; 31. Anode surface; 32. Folding area; 4. PCB adapter board; 41. Anode spring pin; 42. Cathode spring pin; 51. Air inlet connector; 52. Air outlet connector; 6. Sealing gasket; 100. Wafer. Detailed Implementation

[0026] 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.

[0027] 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.

[0028] The following example describes a bonding-type megasonic transmitter head 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.

[0029] Please refer to the reference. Figures 1 to 5 According to an embodiment of the present invention, a bonding-type megasonic wave transmitter head for semiconductor cleaning is provided, comprising a housing (not labeled in the figure), the housing having a receiving cavity (not labeled in the figure), and the opening side of the receiving cavity (i.e., Figure 1A resonant plate 2 capable of sealing the opening is assembled on the lower side shown. A piezoelectric ceramic sheet 3 is attached to the inner side of the resonant plate 2. A PCB adapter plate 4 is also provided in the accommodating cavity. An anode spring pin 41 and a cathode spring pin 42 are provided on the PCB adapter plate 4. The anode spring pin 41 and the cathode spring pin 42 can be welded to the PCB adapter plate 4. The positive terminal of the cable (a coaxial cable in a specific embodiment) is fixed (e.g., welded or bolted) to the PCB adapter plate 4 and electrically connected to the anode spring pin 41. The negative terminal of the cable is fixed (e.g., welded or bolted) to the PCB adapter plate 4 and electrically connected to the cathode spring pin 42. The anode spring pin 41 abuts against the anode surface of the piezoelectric ceramic sheet 3 to achieve an elastic electrical connection between the two. The cathode spring pin 42 abuts against the cathode surface of the piezoelectric ceramic sheet 3 to achieve an elastic electrical connection between the two. The aforementioned anode spring pin 41 and cathode spring pin 42 can specifically use commercially available spring pins to reduce design and manufacturing costs.

[0030] In this technical solution, the PCB adapter board 4 and the piezoelectric ceramic sheet 3 are elastically electrically connected through the aforementioned anode spring pin 41 and cathode spring pin 42. This achieves mechanical connection between the cathode and anode of the PCB adapter board and the cathode and anode surfaces 31 of the piezoelectric ceramic sheet 3, eliminating the need for traditional welding or conductive adhesive connections. This prevents electrical connection failures caused by solder joint fatigue fracture or conductive adhesive aging and detachment, thereby improving the reliability and service life of the emission nozzle.

[0031] In some embodiments, the cathode surface of the piezoelectric ceramic sheet 3 is attached to the inner wall surface of the resonant plate 2, the anode surface 31 of the piezoelectric ceramic sheet 3 is its end face away from the resonant plate 2, the cathode surface has a folded area 32 that is folded towards the anode surface 31 and formed on the anode surface, and the free end of the cathode spring pin 42 abuts against the folded area 32. It is understood that necessary insulation treatment should be performed between the aforementioned anode surface and the folded area 32 to prevent short circuit between the two.

[0032] In this technical solution, the cathode surface that is attached to the resonant plate 2 is formed on the anode surface 31 by folding, which simplifies the structural design of the aforementioned anode spring pin 41 and cathode spring pin 42. The two can be arranged in parallel and respectively contact and connect with the anode surface 31 and the folded area 32, thus simplifying the structural design.

[0033] The piezoelectric ceramic sheet 3 and the resonant plate 2 are bonded together with an adhesive layer. The thickness of this adhesive layer is crucial to the bonding-type megasonic wave transmitter. Excessive adhesive can lead to severe acoustic energy loss, phase distortion, and abnormal frequency response, while insufficient adhesive can cause interface delamination during prolonged operation. Therefore, this invention uses precision fixtures to control the adhesive thickness, i.e., the aforementioned adhesive layer thickness, between 5 micrometers and 150 micrometers. This ensures efficient acoustic energy transmission, stable impedance, excellent sound field consistency, strong bonding strength, uniform stress distribution, and long-term operational reliability.

[0034] In some embodiments, the housing includes a frame 11 and a cover plate 12. The resonant plate 2 and the cover plate 12 are respectively connected to opposite end faces of the frame 11, and the PCB adapter plate 4 is connected to the inner wall of the cover plate 12. Specifically, the cover plate 12 and the frame 11 are detachably connected by a plurality of screws 122. In a preferred embodiment, the aforementioned cover plate 12, frame 11 and screws 122 are all made of corrosion-resistant plastic material.

[0035] In this technical solution, the aforementioned frame 11 serves as the main frame of the transmitter head, and a cover plate 12 is detachably installed on one side end face, which facilitates the assembly, disassembly and maintenance of each component in the accommodating cavity. The aforementioned PCB adapter plate 4 is fixedly connected to the inner wall of the cover plate 12. When the cover plate 12 is assembled on the frame 11, the anode spring pin 41 and the cathode spring pin 42 of the PCB adapter plate 4 will be electrically connected to the piezoelectric ceramic sheet 3 respectively, thus simplifying the assembly process.

[0036] In some embodiments, the cover plate 12 is connected to an air inlet connector 51 and an air outlet connector 52, both of which are in communication with the accommodating space. This allows for a circulating cooling airflow with an external air-cooling system, introducing external cooling air into the accommodating cavity to achieve efficient heat exchange and cooling of the heat source components within the cavity, ensuring reliable operation of the equipment. In one specific embodiment, the cooling airflow may be, for example, nitrogen.

[0037] In one specific embodiment, the air inlet connector 51 introduces a 2m long BNC coaxial cable and a temperature cable. The temperature cable and the coaxial cable are encapsulated in a soft, fine-tipped corrugated hose for waterproofing and serve as the air outlet of the air-cooling system. The air outlet connector 52 is connected to an external air-cooling device through an air guide tube and serves as the air inlet of the air-cooling system (i.e., the air outlet of the transmitter).

[0038] In some embodiments, a sealing gasket 6 is sandwiched between the mating surfaces of the frame 11 and the cover plate 12 to ensure the sealing of the aforementioned accommodating cavity. The sealing gasket 6 may be, for example, a waterproof silicone gasket.

[0039] In some embodiments, the outer end face of the cover plate 12 is provided with mounting screw holes 121 for connecting with an external support component (not shown in the figure). In specific use, a corresponding threaded component can be threaded into the mounting screw hole 121 to connect the transmitter head and the external support component as one unit. There may be multiple mounting screw holes 121.

[0040] In some embodiments, the outer peripheral edge of the resonant plate 2 is formed with a flange (not indicated in the figure) facing the side of the frame 11. The resonant plate 2 is embedded and bonded to the frame 11 through the flange, which can achieve a reliable connection between the resonant plate 2 and the frame 11, and also ensure the sealing of the mating position of the two.

[0041] In some embodiments, when the bonding megasonic transmitter is in use, its projection on the plane of the wafer 100 is fan-shaped, so as to support the rapid switching of cleaning of wafers 100 with different radius sizes such as 8 / 12 inches, and to adapt to multiple processes such as CMP, wet etching, and resist removal. The bottom wafer can be rotated to achieve cleaning of the entire circular surface.

[0042] In one specific embodiment, the aforementioned resonant plate 2 is made of materials such as silicon carbide, alumina, quartz, or stainless steel, and uses the optimal matching thickness corresponding to the mega-sonic operating frequency. For example, alumina single crystal can be used as an ideal resonator material: it can provide an atomically smooth surface (Ra<0.1nm), with a flatness of less than 20um; its high rigidity can effectively suppress the thermal deformation of the nozzle during long-term operation (thermal expansion coefficient 5.3×10- 6 / K); It has excellent compatibility with all chemical environments, such as not releasing any ions in environments with highly corrosive cleaning solutions like hydrogen fluoride, thus meeting high cleanliness requirements. In this invention, experiments have determined that at a mega-sound frequency of 0.8–1 MHz, the ideal cleaning effect is achieved when the thickness of the resonant plate 2 is half the wavelength, at a distance of 1–5 mm from the nozzle.

[0043] The aforementioned piezoelectric ceramic sheet 3 can be, for example, lead zirconate titanate piezoelectric ceramic.

[0044] In practical applications, a cleaning chemical liquid is sprayed onto the object to be cleaned (such as wafer 100). An AC current signal is input through the spring pins (i.e., the aforementioned anode spring pin 41 and cathode spring pin 42). The piezoelectric ceramic sheet 3 generates mechanical vibration under the alternating voltage, emitting megasonic wave energy, which is transmitted through the resonant plate 2 below. This megasonic wave energy is then transferred to the cleaning liquid, where it cleans impurities on wafer 100 using microacoustic flow energy, which are subsequently carried away by the liquid flow. The transmitting head is connected and fixed to an external mounting carrier via the aforementioned mounting screw hole 121, forming a circumferential or radial relative motion with the wafer 100 to be cleaned below.

[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 bonding-type megasonic wave transmitter for semiconductor cleaning, characterized in that, The device includes a housing with a cavity. A resonant plate (2) capable of sealing the opening is assembled on one side of the cavity. A piezoelectric ceramic sheet (3) is attached to the inner side of the resonant plate (2). A PCB adapter plate (4) is also provided inside the cavity. An anode spring pin (41) and a cathode spring pin (42) are provided on the PCB adapter plate (4). The positive terminal of the cable is fixed on the PCB adapter plate (4) and electrically connected to the anode spring pin (41). The negative terminal of the cable is fixed on the PCB adapter plate (4) and electrically connected to the cathode spring pin (42). The anode spring pin (41) abuts against the anode surface of the piezoelectric ceramic sheet (3), and the cathode spring pin (42) abuts against the cathode surface of the piezoelectric ceramic sheet (3).

2. The fitted megasonic transmitter head according to claim 1, characterized in that, The cathode surface of the piezoelectric ceramic sheet (3) is attached to the inner wall surface of the resonant plate (2), the anode surface (31) of the piezoelectric ceramic sheet (3) is its end face away from the resonant plate (2), the cathode surface has a folded area (32) that is folded toward the anode surface (31) and formed on the anode surface, and the free end of the cathode spring pin (42) abuts against the folded area (32).

3. The fitted megasonic transmitter according to claim 2, characterized in that, The piezoelectric ceramic sheet (3) and the resonant plate (2) are bonded together by an adhesive layer, the thickness of which is 5 micrometers to 150 micrometers.

4. The fitted megasonic transmitter according to claim 1, characterized in that, The outer casing includes a frame (11) and a cover plate (12). The resonant plate (2) and the cover plate (12) are respectively connected to the opposite two end faces of the frame (11), and the PCB adapter plate (4) is connected to the inner wall surface of the cover plate (12).

5. The fitted megasonic transmitter according to claim 4, characterized in that, The cover plate (12) is connected to an air inlet connector (51) and an air outlet connector (52), both of which are connected to the accommodating space.

6. The fitted megaacoustic transmitter according to claim 4, characterized in that, A sealing gasket (6) is held between the mating surfaces of the frame (11) and the cover plate (12).

7. The fitted megaacoustic transmitter according to claim 4, characterized in that, The outer end face of the cover plate (12) is provided with mounting screw holes (121) for connecting with external support components.

8. The fitting megaacoustic transmitter according to claim 4, characterized in that, The cover plate (12) and the frame (11) are detachably connected by a plurality of screws (122).

9. The fitted megaacoustic transmitter according to claim 4, characterized in that, The outer peripheral edge of the resonant plate (2) is formed with a flange facing the side of the frame (11), and the resonant plate (2) is embedded and bonded to the frame (11) via the flange.

10. The fitted megasonic transmitter according to claim 1, characterized in that, When the attached megasonic transmitter is in use, its projection on the plane of the wafer (100) is fan-shaped.

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