Non-contact atomization device based on resonant cavity and photoresist coating method

Abstract

The application provides a kind of non-contact atomization device based on resonant cavity and photoresist coating method, the non-contact atomization device based on resonant cavity includes ultrasonic device, liquid supply system, acoustic chamber, ultrasonic device is arranged at the opening of acoustic chamber, the liquid supply system is arranged in acoustic chamber and ultrasonic device is opposite position, acoustic chamber is provided with resonant cavity, resonant cavity is arranged in the opposite position of ultrasonic device.The application has simple structure, stable and reliable performance, easy processing, low device cost, small power loss;The application can realize the focusing and enhancement of sound wave in local cavity, the energy utilization rate, particle size controllability and particle size scale range are optimized during implementation process;The application has large coating area, high uniformity, is not limited by wafer substrate surface morphology, can realize photoresist conformal coating and other technologies of complex three-dimensional microstructure;Atomization process has anti-pollution resistance and anti-blocking property.

Description

Technical Field

[0001] This invention relates to the fields of photoresist coating and advanced packaging of structured wafers, and particularly to a non-contact atomization device and photoresist coating method based on a resonant cavity. Background Technology

[0002] Photolithography, encompassing resist coating, exposure, and development, is a core process in the fabrication of nanoscale patterns for integrated circuits, significantly impacting chip manufacturing precision and integration density. Wafer resist coating is a crucial step in the photolithography process; the thickness and uniformity of the resist coating directly determine the resolution and fineness of the developed pattern, and have a significant impact on the reliability, yield, and device performance of the integrated circuit.

[0003] Traditional photoresist coating primarily employs spin coating, which involves uniformly coating the photoresist onto the surface of a high-speed rotating wafer substrate using centrifugal force. The thickness and uniformity of spin coating depend on factors such as the viscosity coefficient between the photoresist and the substrate, rotation speed, rotation time, and surface morphology. However, the high rotation speed of spin coating easily leads to rapid evaporation of the photoresist and causes transient and turbulent flow phenomena in the airflow field around the wafer substrate, making it difficult to effectively control the uniformity of the photoresist film. The large centrifugal force of spin coating causes a large amount of photoresist to be thrown off the wafer substrate, with approximately 90% of the photoresist wasted in the spin coating process, resulting in a significant increase in manufacturing costs. For wafer substrates with complex microstructures, the radial flow of photoresist in the spin coating process causes the colloid to accumulate in localized areas of the microstructure, making it difficult to precisely control the thickness and uniformity of the photoresist coating. Therefore, spin coating is only suitable for flat wafer substrates and is difficult to achieve uniform coating of photoresist on trench structures with large topographic undulations and high aspect ratios.

[0004] Conventional ultrasonic photoresist atomization technology is typically a contact atomization method, which mainly utilizes high-frequency vibration to form micro-droplets from photoresist droplets. The driving frequency of this type of atomization technology is usually between 100kHz and 200kHz, and the atomization scale can only reach 18μm, making it difficult to achieve smaller atomized droplets, and the uniformity is ≤70%. For through-silicon via (TST) structures with an aspect ratio ≥5:1, even smaller droplets (<10μm diameter) and higher uniformity are required to achieve good conformal coverage.

[0005] In recent years, 3D-IC packaging and MEMS (Micro-Electro-Mechanical Systems) have further developed towards multi-layer and multi-layer structures. Device sizes are becoming smaller and more complex, and the sensitivity of wafers to impurity content is increasing accordingly. Surface quality directly affects device yield, performance, and reliability. Highly integrated microstructure devices often have non-flat surfaces, such as channels, steps, V-grooves, and deep holes. Furthermore, through-silicon via (TSV) technology, a crucial process in 3D-IC packaging, features high 3D stacking density and on-chip vertical interconnect structures. Current ultrasonic atomization spraying techniques present numerous challenges for uniform and effective coating of these complex microstructures, hindering further development of semiconductor device manufacturing processes. There is an urgent need for new coating processes to achieve conformal photoresist coating on wafers with complex three-dimensional microstructures.

[0006] Current ultrasonic atomization spraying technology faces many difficulties in achieving uniform and effective coating of the aforementioned complex microstructures, such as large particle size, uneven particle size distribution, serious photoresist waste, nozzle clogging, and the inability to conformally coat photoresist on complex three-dimensional microstructures. Summary of the Invention

[0007] To address the shortcomings of the prior art, this invention provides a non-contact atomization device and photoresist coating method based on a resonant cavity, thereby solving the problems mentioned in the background art, such as the difficulty in effectively controlling the uniformity of the photoresist film layer during the traditional photoresist coating process; the waste of approximately 90% of the photoresist in the spin coating process, leading to a significant increase in manufacturing costs; and the difficulty in accurately controlling the thickness and uniformity of the photoresist coating for wafer substrates with complex microstructures.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A non-contact atomizing device based on a resonant cavity includes an ultrasonic device, a liquid supply system, and a sound chamber. The ultrasonic device is located at the opening of the sound chamber, and the liquid supply system is located inside the sound chamber relative to the ultrasonic device. A resonant cavity is provided inside the sound chamber, and the resonant cavity is located relative to the ultrasonic device.

[0010] Furthermore, the ultrasonic device includes an ultrasonic transducer, an amplitude transformer, and a tool head. The ultrasonic transducer and the amplitude transformer are connected by a thread, and the tool head is fixedly connected to the amplitude transformer.

[0011] Furthermore, the liquid supply system is a glass microneedle, which extends into the acoustic chamber through a hole in the top wall of the acoustic chamber, with the tip of the microneedle positioned in the resonant cavity.

[0012] Furthermore, the bottom of the sound chamber is fixed on the lifting platform. The shape of the inside of the sound chamber and the sound chamber outlet can be set as a polygon or a cylinder. The tool head extends into the opening at the top of the sound chamber. The lower end of the tool head should be flush with the upper end of the inner wall of the sound chamber. The distance between the tool head and the lower wall of the sound chamber can be adjusted. The shape of the tool head is consistent with the shape of the opening at the top of the sound chamber, which can be circular or polygonal.

[0013] Furthermore, the length of the amplitude transformer is an integer multiple of half the ultrasonic wavelength.

[0014] Furthermore, the resonant cavity can be a Fabry-Perot resonant cavity, a Helmholtz resonant cavity, a spherical resonant cavity, a cylindrical resonant cavity, or a rectangular resonant cavity.

[0015] Furthermore, multiple liquid supply systems can be installed in the acoustic chamber.

[0016] Furthermore, the liquid supply system is equipped with a device for adjusting the focusing speed of photoresist droplets. The device is located around the outside of the resonant cavity wall in the acoustic chamber. Inside the device, there is a spiral air passage and an air passage inlet. The air passage inlet is located on one of the walls, and an air passage buffer chamber is located adjacent to the air passage inlet. The air passage inlet is connected to an air pump. Gas enters from the air passage inlet, passes through the air passage buffer chamber, and then flows out along the air passage outlet outside the resonant cavity wall.

[0017] A non-contact atomizing photoresist coating method based on a resonant cavity includes the following steps:

[0018] Step 1: Adjust the relative position of the ultrasonic device and the sound chamber;

[0019] Step 2: Place the photoresist material to be atomized into a sealed container;

[0020] Step 3: Turn on the ultrasonic signal generator, input the frequency, voltage and waveform signal that match the ultrasonic transducer, and input the signal into the ultrasonic transducer after passing through the power amplifier;

[0021] Step 4: Fine-tune the distance between the ultrasonic transducer tool head and the lower wall of the sound chamber to create a stable sound field in the sound chamber;

[0022] Step 5: Adjust the flow rate of the photoresist raw material to deliver the photoresist to the standing wave pressure node position in the resonant cavity. Under the excitation of the constantly changing pressure field and velocity field, the photoresist droplets deform, break up, and atomize.

[0023] The advantages of this invention over the prior art are:

[0024] (1) This invention proposes a non-contact atomization device and coating method based on a resonant cavity. It achieves fine atomization of photoresist droplets by utilizing the non-contact characteristics of sound waves, which can overcome the limitations and shortcomings of traditional atomization methods. The size of the acoustic chamber matching the ultrasonic frequency is calculated by using acoustic waveguide theory. The resonant cavity can realize the focusing and enhancement of sound waves in the local cavity. During the implementation process, the energy utilization rate, particle size controllability, and particle size range are optimized.

[0025] Compared to spin coating and conventional ultrasonic atomization, the non-contact ultrasonic atomization coating method atomizes photoresist into micron-sized uniform droplets. The atomized droplets are small in size and uniform in distribution. Guided by airflow, these micron-sized photoresist droplets, with a diameter <10μm, are uniformly dispersed onto the wafer substrate surface, achieving uniform and controllable photoresist coating. Spray coating is a non-contact film formation process with advantages such as large coverage area, high uniformity, no limitation by wafer substrate surface morphology, and the ability to achieve conformal coating of photoresist onto complex three-dimensional microstructures.

[0026] (2) Spin coating is only suitable for wafer substrates with smooth surfaces. Ultrasonic atomization coating produces photoresist droplets with larger diameters (≥18μm), which cannot be used on wafers with high aspect ratios. The atomization coating process of this invention produces photoresist droplets with smaller diameters (≤10μm), more uniform particle size distribution, and higher concentration, enabling uniform photoresist film formation on MEMS wafer surfaces with high aspect ratios (≥5:1). Furthermore, this atomization technology can effectively reduce photoresist waste and significantly lower process costs.

[0027] (3) In the practice of contact ultrasonic atomization, the ultrasonic vibration causes rapid evaporation at the nozzle tip, which has a high probability of causing clogging of the nozzle micropores. Micropore clogging is one of the important defects of the current atomized coating process. Once the micropores are clogged, they are difficult to detect during the process, resulting in uneven coating of the wafer and rework. The non-contact atomization characteristics of the device and method provided by the present invention improve the anti-pollution resistance and anti-clogging properties during the atomization process.

[0028] (4) The non-contact atomizing device based on a resonant cavity of the present invention has good potential for expansion and optimization. For example, the size, velocity, and particle size distribution of the atomized photoresist droplets can be controlled by adjusting the voltage, frequency, distance between the tool head and the lower wall of the acoustic chamber, and adjusting the supply of photoresist. For coating processes with requirements on spray width or spray particle size velocity, an adjustment device for the focusing velocity of photoresist droplets can be added at the nozzle to effectively control the focusing degree and particle size velocity of the spray. For coating requirements of different sizes, configuring a reasonable number of liquid supply system arrays reduces the number of scans and improves the spraying efficiency.

[0029] (5) In addition to being used for photoresist atomization and uniform coating, the non-contact atomization device based on a resonant cavity of the present invention can also be used in wafer cleaning processes. The non-contact atomization device based on a resonant cavity of the present invention has small atomization particle size and uniform atomization particle size distribution. Under the guidance of high-speed airflow, micron-sized pure water droplets are uniformly sprayed onto the surface of the wafer structure, thereby achieving effective cleaning of the complex surface of the wafer structure.

[0030] (6) The non-contact atomizing device based on a resonant cavity of the present invention has a simple structure, stable and reliable performance, is easy to process, has low device cost and low power loss. Attached Figure Description

[0031] Figure 1 A schematic diagram of the structure of a non-contact atomizing device based on a resonant cavity according to Embodiment 1 of the present invention;

[0032] Figure 2 A schematic diagram of the distribution of sound pressure, vibration velocity, and radiation pressure in a standing wave field according to Embodiment 1 of the present invention;

[0033] Figure 3 Schematic diagram of the forces acting on photoresist droplet 5 in a standing wave field in Embodiment 1 of the present invention;

[0034] Figure 4 Embodiment 1 of the present invention: a device for adjusting the focusing speed of photoresist droplets;

[0035] Figure 5 A control principle diagram of a non-contact atomizing device based on a resonant cavity according to Embodiment 1 of the present invention;

[0036] Figure 6 Schematic diagram of the scanning motion of the nozzle on the wafer in Embodiment 1 of the present invention; 6(a) is a schematic diagram of the cleaning path, and 6(b) is a schematic diagram of the pretreatment and photoresist spraying path;

[0037] Figure 7 Schematic diagram of the dual-nozzle spray head structure in Embodiment 2 of the present invention;

[0038] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0039] 1-Ultrasonic transducer; 2-Amplitude transformer; 3-Tool head; 4-Glass microneedle; 5-Photoresist droplet; 6-Resonant cavity; 7-Acoustic chamber; 8-Wafer; 9-Photoresist spraying path; 10-Gas inlet; 11-Gas buffer chamber; 12-Resonant cavity wall. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings.

[0041] Example 1

[0042] like Figure 1 As shown, the present invention provides a non-contact atomization device based on a resonant cavity: including an ultrasonic device, a liquid supply system, and a sound chamber 7, wherein the ultrasonic device includes an ultrasonic transducer 1, an amplitude transformer 2, and a tool head 3. The ultrasonic transducer 1 and the amplitude transformer 2 are connected by threads, and the tool head 3 is fixedly connected to the amplitude transformer 2. The material of the amplitude transformer 2 should be selected to have good acoustic properties, such as titanium alloy or aluminum. Usually, when the length of the amplitude transformer 2 is an integer multiple of half the ultrasonic wavelength, the amplitude of the standing wave formed will reach its peak, which has the most efficient transmission and amplification efficiency.

[0043] The opening of the acoustic chamber 7 is square, and the resonant cavity 6 is cylindrical. Furthermore, the opening and resonant cavity 6 can be configured with different sizes and shapes as needed. An opening is provided at the left end of the top wall of the acoustic chamber 7, and an opening for the glass microneedle 4 to pass through is provided at the right end of the top wall of the acoustic chamber 7. The resonant cavity 6 is located on the bottom wall of the acoustic chamber 7, with the lower part of the resonant cavity 6 serving as the outlet of the acoustic chamber 7. The square opening at the top of the acoustic chamber 7 serves as the excitation surface for sound waves. Sound waves propagate within the acoustic chamber 7, are amplified by the resonant cavity 6, and then propagate out from the lower outlet of the acoustic chamber 7. The cylindrical design, due to its geometry, provides a strong antinode at the outlet of the acoustic chamber 7. In this embodiment, a cylindrical design is used for the outlet of the acoustic chamber 7. The acoustic chamber 7 can be made of metal, quartz, glass, nylon, or resin. To minimize sound wave loss within the acoustic chamber 7, the density of the material used in the acoustic chamber 7 needs to be ≥1 g / cm³. 3 The inner wall of the acoustic chamber 7 needs to be flat and smooth. In this invention, the acoustic chamber 7 is made of acrylic plastic, also known as plexiglass, and is manufactured by a CNC machining center.

[0044] The resonant cavity 6, derived from an optical resonant cavity, is innovatively introduced into the acoustic field in this invention. The resonant cavity 6 is located in the stable antinode region of the standing wave within the acoustic chamber 7, i.e., at the other end of the ultrasonic device. The standing wave energy is concentrated in the antinode region, with the greatest deformation and potential energy at the node. Kinetic and potential energy continuously transform and transfer between the vicinity of the antinode and the vicinity of the node, resulting in a high kinetic energy amplitude in the standing wave. The resonant cavity 6 described in this invention can be a Fabry-Perot resonant cavity, a Helmholtz resonant cavity, a spherical resonant cavity, a cylindrical resonant cavity, or a rectangular resonant cavity. The type of resonant cavity 6 can be selected according to actual needs. The resonant cavity 6 requires a material density ≥1 g / cm³. 3 The resonant cavity 6 needs to be flat and smooth. The ultrasonic waves are focused and enhanced by multiple reflections and interferences between the ultrasonic waves in the smooth cavity.

[0045] This invention uses the multiphysics simulation software COMSOL MULTIPHYSICS to establish an axisymmetric linear acoustic model to simulate the sound pressure distribution within the acoustic chamber 7 and the resonant cavity 6. In this embodiment, the simulation uses a resonant frequency of 20 kHz. The dimensions of the acoustic chamber 7, matching the ultrasonic frequency, are calculated using acoustic waveguide theory. The experiment optimizes the dimensions of the acoustic chamber 7, the diameter and length of the resonant cavity 6, and the distance between the tool head 3 and the lower wall of the acoustic chamber 7. When the ultrasonic transducer 1 continuously generates high-frequency vibrations at the same resonant frequency at the upper port of the acoustic chamber 7, a large number of standing waves are formed in the sound field due to the restriction of ultrasonic propagation by the inner wall of the acoustic chamber 7. Theoretically, the sound pressure at any location in the acoustic chamber 7 is a linear superposition of an infinite number of standing wave sound pressures. The resonant cavity 6 is located in the antinode region of the standing waves in the sound field, such as... Figure 3 As shown, in its vertical direction, upward and downward sound pressures are generated, exhibiting a sinusoidal distribution. The points where the upward and downward sound pressures intersect are sound pressure nodes. The sound pressure and the vibration velocity of the medium particles in the standing wave sound field continuously change along the direction of sound wave propagation. Figure 2 The distribution of sound pressure, particle velocity in the medium, and sound radiation force along the Z-axis in the standing wave sound field is given. The fluid medium in the resonant cavity 6 undergoes periodic reciprocating motion under the excitation of the sound source, generating a continuous forward average pressure on the photoresist droplet 5 in the sound field. This results in sound radiation force on the surface of the photoresist droplet 5, which plays a role in the deformation and movement of the photoresist droplet 5 in the sound field. The photoresist droplet 5 at the tip of the glass microneedle 4 will be subjected to the constantly changing excitation of the surrounding pressure and velocity fields in the resonant cavity 6, causing it to deform, break up, and atomize.

[0046] The formula for calculating the radiative force of photoresist droplet 5 is as follows:

[0047]

[0048] Where: F represents the acoustic radiation force experienced by the photoresist droplet 5; p represents the acoustic pressure intensity (Pa) at the corresponding point; ρ0 represents the density of the air medium (kg / m³). 3 c0 represents the velocity of the sound wave (m / s); v represents the velocity of the fluid medium particles (m / s); r represents the position coordinates; t represents time.

[0049] The liquid supply system is located inside the acoustic chamber 7 and is positioned opposite the ultrasonic device. The liquid supply system consists of glass microneedles 4, which extend into the acoustic chamber 7 through holes in the top wall. The needle tip is positioned within the resonant cavity 6. The finer diameter of the glass microneedles 4 allows for the generation of fine atomized photoresist droplets. The larger the needle tip diameter, the larger the diameter of the outflowing photoresist droplets 5. Without other forces, the surface tension of the photoresist droplets 5 keeps them spherical, requiring more sophisticated atomization equipment and resulting in relatively large atomized particle sizes. The ultrasonic transducer 1 contains a piezoelectric ceramic plate. This piezoelectric ceramic plate generates high-frequency mechanical vibrations at the resonant frequency. The amplitude is further amplified by the amplitude transformer. The amplified end displacement, through the square tool head 3, allows the sound waves to be transmitted more efficiently into the acoustic chamber 7.

[0050] like Figure 1 As shown, the tool head 3 extends into the square opening at the top of the sound chamber 7. The lower end face of the tool head 3 should be flush with the upper end face of the inner wall of the sound chamber 7. The distance between the lower end face of the tool head 3 and the lower wall of the sound chamber 7 can be finely adjusted to achieve the optimal standing wave sound field. The shape of the tool head 3 is not limited to square; it can be circular or polygonal.

[0051] like Figure 4 As shown, for coating processes requiring spray width or spray particle velocity, an adjustment device for the focusing speed of photoresist droplets can be added to the acoustic chamber 7. The adjustment device is located around the resonant cavity wall 12 in the acoustic chamber 7. The adjustment device has a spiral air passage and an air passage inlet 10 inside. The air passage inlet 10 is located on one of the walls. An air passage buffer chamber 11 is located adjacent to the air passage inlet 10. The air passage inlet 10 is connected to an air pump. Gas enters from the air passage inlet 10, passes through the air passage buffer chamber 11, and then flows out along the air passage outlet outside the resonant cavity wall 12. The focusing degree and atomization particle velocity can be adjusted by adjusting the input air pressure of the air pump.

[0052] This invention provides a non-contact atomization device based on a resonant cavity, which can be used not only for non-contact fine atomization and uniform coating of photoresist, but also for wafer 8 cleaning processes. During wafer 8 cleaning, the distance between the outlet of the acoustic chamber 7 and the wafer 8 is adjusted, a flow pump is used to achieve precise control of the pure water flow rate, and a device for adjusting the focusing speed of the photoresist droplets is used. High-speed, high-flow-rate pure water droplets are sprayed at a speed of 10–20 m / s, following a preset cleaning path. Figure 6 As shown in (a), the non-contact atomizing device based on a resonant cavity scans the entire wafer 8, and micron-sized pure water droplets are uniformly sprayed onto the surface of the wafer 8 structure. The rotating stage drives the wafer 8 to rotate at a high speed of 400 to 3000 r / min, thereby removing impurity particles from the surface of the wafer 8.

[0053] The control principle of the non-contact atomizing device based on a resonant cavity is as follows: Figure 5 As shown, the control module of the device includes a motion control module, an adsorption and heating module, an ultrasonic excitation module, an ultrasonic drive module, an acoustic wave transmission module, and a flow control module. The host computer is bidirectionally connected to the main controller, the output of the main controller is connected to the input of the ultrasonic drive module, and the main controller is bidirectionally connected to the flow control module, the adsorption and heating module, and the motion control module. The output of the ultrasonic drive module acts on the wafer 8 through the ultrasonic excitation module, the adsorption and heating module acts directly on the wafer 8, and the motion control module acts directly on the wafer 8.

[0054] The motion control module includes a motion controller, an XYZ three-axis motion platform, and a grating ruler. The three-axis motion platform is positioned above the wafer 8. The input of the three-axis motion platform is connected to the output of the motion controller. The input of the non-contact atomizing device based on a resonant cavity is connected to the output of the three-axis motion platform. The three-axis motion platform receives commands from the motion controller and drives the non-contact atomizing device to perform three-dimensional motion, ensuring precise and uniform coating of atomized droplets onto a designated area of ​​the wafer 8. The X and Y axis motion platforms enable the non-contact atomizing device to scan the entire wafer 8, while the Z-axis motion platform controls the distance between the outlet of the acoustic chamber 7 and the wafer 8. The motion controller is connected to the main controller and is circuitically connected to a servo motor and a grating ruler. It receives and processes the displacement signals from the X and Y axis grating rulers and controls the motion signals applied by the servo motor. Figure 6 This is a schematic diagram of the scanning motion of a non-contact atomizing device based on a resonant cavity on wafer 8 according to the present invention; Figure 6 (a) is a schematic diagram of the cleaning path. Figure 6 (b) is a schematic diagram of the pretreatment and photoresist spraying path.

[0055] The adsorption and heating module is a constant temperature heating stage, which is fixed on the rotating platform at the lower outlet of the acoustic chamber 7. The constant temperature heating stage has a heating effect on the wafer 8. The surface of the constant temperature heating stage has vacuum adsorption holes, and the vacuum adsorption holes are connected to the gas path. The vacuum adsorption holes play a role in adsorbing and fixing the wafer 8.

[0056] The ultrasonic excitation module includes an ultrasonic transducer 1, an amplitude transformer 2, and a tool head 3. The ultrasonic excitation module primarily provides high-frequency ultrasonic waves to the ultrasonic transducer 1 in the aforementioned non-contact atomization device based on a resonant cavity. The ultrasonic transducer 1 can be a piezoelectric ultrasonic transducer or a magnetostrictive transducer. The piezoelectric ceramic plate inside the ultrasonic transducer 1 converts electrical energy into mechanical energy based on the inverse piezoelectric effect. Driven by a power amplifier, the piezoelectric ceramic plate generates high-frequency vibrations. Through the transmission and amplification effect of the amplitude transformer 2 and the tool head 3, these high-frequency vibrations form a stable standing wave sound field within the sound chamber 7. The ultrasonic transducer 1 uses sinusoidal, cosine, or square wave signals, and its driving frequency range is 1kHz-2MHz. The ultrasonic transducer 1 maximizes its vibration efficiency at its resonant frequency, creating a higher intensity sound field at the outlet of the sound chamber 7. In this embodiment, the resonant frequency of the ultrasonic transducer 1 is 20kHz, but ultrasonic transducers with different resonant frequencies can be selected according to actual needs.

[0057] The ultrasonic drive module includes an ultrasonic signal generator and a power amplifier. The output of the ultrasonic signal generator is connected to the ultrasonic transducer via the power amplifier. The ultrasonic drive module provides a drive signal to the ultrasonic transducer 1. The ultrasonic signal generator is a device used to set the waveform, output frequency, phase, period, and output level electrical signal. The sinusoidal signal output by the ultrasonic signal generator is amplified and then impedance-matched to the ultrasonic transducer 1 via a matching circuit to drive the ultrasonic transducer 1. Alternatively, the ultrasonic drive module can directly drive the ultrasonic transducer 1 using an ultrasonic power supply. When the high-frequency AC signal generated by the ultrasonic signal generator matches the resonant frequency of the ultrasonic transducer 1, the ultrasonic transducer 1 can achieve its optimal output efficiency.

[0058] The flow control module includes a flow control pump, glass microneedles 4, and a pipeline for delivering atomized solution. The flow control pump is connected to the inlet of the glass microneedles 4 via the pipeline. The flow control pump delivers the atomized solution into the glass microneedles 4 through the pipeline. The flow control module is mainly used to achieve precise regulation and matching of atomization flow rate and sonication energy. If the liquid supply is too fast, it will cause a mismatch between the atomization of photoresist droplets 5 and the sonication energy, resulting in a large atomization size uneven distribution. The flow pump is used to achieve precise control of the photoresist flow rate, thereby effectively controlling the particle size and distribution of the atomized droplets. The photoresist supply flow rate set in this invention is 0-10 ml / min.

[0059] Example 2

[0060] like Figure 7As shown, when wafer 8 requires large-area coating, the non-contact atomizing device based on a resonant cavity is the same as in embodiment 1, except that two liquid supply systems can be set in the acoustic chamber 7, respectively set at both ends of the acoustic chamber 7, and the ultrasonic device is set in the middle of the acoustic chamber. For different sizes of photoresist coating requirements, configuring a reasonable number of liquid supply system arrays can effectively reduce the number of scans and improve the atomization coating efficiency.

[0061] A non-contact atomization device and photoresist coating method based on a resonant cavity are disclosed. The method includes: adjusting the relative position of the ultrasonic device and the acoustic chamber 7; connecting the ultrasonic transducer 1 and the amplitude transformer 2, and adjusting the relative position of the ultrasonic transducer 1 and the acoustic chamber 7; placing the photoresist material to be atomized into a sealed container, such as an ink cartridge; setting the waveform, output frequency, phase, period, and output level electrical signal through an ultrasonic signal generator; the signal, after passing through a power amplifier, drives the ultrasonic transducer 1; the high-frequency vibration generated by the ultrasonic transducer 1 and the reflecting end within the acoustic chamber 7 form a stable standing wave within the cavity of the acoustic chamber 7. The resonant cavity 6 is positioned at the antinode of the standing wave. The ultrasonic waves are focused and enhanced through multiple reflections and interferences within the resonant cavity 6. The distance between the tool head 3 of the ultrasonic transducer 1 and the lower wall of the acoustic chamber 7 is finely adjusted to form a stable sound field within the acoustic chamber 7. The flow rate of the photoresist material is adjusted: the photoresist solution is transported to the center of the resonant cavity 6 through a pipeline connected to the glass microneedle 4 by adjusting the flow pump. The photoresist droplet 5 located at the glass microneedle 4 is deformed, broken, and atomized due to the constantly changing excitation of the surrounding pressure and velocity fields in the focused and enhanced standing wave field of the resonant cavity 6.

Claims

1. A non-contact atomizing device based on a resonant cavity, comprising an ultrasonic device, a liquid supply system, and a sound chamber (7), wherein an opening is provided at the left end of the top wall of the sound chamber (7), the ultrasonic device is disposed at the opening of the sound chamber (7), and the liquid supply system is disposed inside the sound chamber (7) in a position opposite to the ultrasonic device, characterized in that, A resonant cavity (6) is provided on the bottom wall of the acoustic chamber (7), and the resonant cavity (6) is located at the relative position of the ultrasonic device; the liquid supply system is a glass microneedle (4), which extends into the acoustic chamber (7) through the opening in the top wall of the acoustic chamber (7), and the tip of the needle is located in the resonant cavity (6); The ultrasonic device includes an ultrasonic transducer (1), an amplitude transformer (2), and a tool head (3). The ultrasonic transducer (1) and the amplitude transformer (2) are connected by threads, and the tool head (3) is fixedly connected to the amplitude transformer (2). The liquid supply system is equipped with a photoresist droplet focusing speed adjustment device. The adjustment device is located around the resonant cavity wall (12) in the acoustic chamber (7). The adjustment device has a spiral air path and an air path inlet (10) inside. The air path inlet (10) is located on one of the walls. An air path buffer chamber (11) is provided adjacent to the air path inlet (10). The air path inlet (10) is connected to an air pump. Gas enters from the air path inlet (10), passes through the air path buffer chamber (11), and then flows out along the air path outlet outside the resonant cavity wall (12).

2. The non-contact atomizing device based on a resonant cavity according to claim 1, characterized in that, The lower part of the resonant cavity (6) is the outlet of the sound chamber (7). The shape inside the sound chamber (7) and the shape of the outlet of the sound chamber (7) are set to be cylindrical or polygonal. The tool head (3) extends into the opening at the upper end of the sound chamber (7). The lower end face of the tool head (3) should be flush with the upper end face of the inner wall of the sound chamber (7). The distance between the tool head (3) and the lower wall of the sound chamber (7) can be adjusted. The shape of the tool head (3) is consistent with the shape of the opening at the upper end of the sound chamber (7), which is circular or polygonal.

3. The non-contact atomizing device based on a resonant cavity according to claim 1, characterized in that, The length of the amplitude transformer (2) is an integer multiple of half the ultrasonic wavelength.

4. The non-contact atomizing device based on a resonant cavity according to claim 1, characterized in that, The resonant cavity (6) is a Fabry-Perot resonant cavity, a Helmholtz resonant cavity, a spherical resonant cavity, a cylindrical resonant cavity, or a rectangular resonant cavity.

5. The non-contact atomizing device based on a resonant cavity according to claim 1, characterized in that, Multiple liquid supply systems are installed in the acoustic chamber (7).

6. A non-contact atomization photoresist coating method based on a resonant cavity, implemented using the non-contact atomization device based on a resonant cavity as described in claim 1, characterized in that... Includes the following steps: Step 1: Adjust the relative position of the ultrasonic device and the acoustic chamber (7); Step 2: Place the photoresist material to be atomized into a sealed container; Step 3: Turn on the ultrasonic signal generator, input the frequency, voltage and waveform signal that match the ultrasonic transducer (1), and input the signal into the ultrasonic transducer (1) after passing through the power amplifier; Step 4: Fine-tune the distance between the tool head (3) of the ultrasonic transducer (1) and the lower wall of the sound chamber (7) to form a stable sound field in the sound chamber (7); Step 5: Adjust the flow rate of the photoresist raw material so that the photoresist is delivered to the standing wave pressure node position in the resonant cavity (6). Under the excitation of the constantly changing pressure field and velocity field, the photoresist droplet (5) deforms, breaks, and atomizes.

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